Sulfonation and Sulfation - Industrial & Engineering Chemistry (ACS

2022

INDUSTRIAL AND ENGINEERING CHEMISTRY

(59)Petroleum Refiner,30,N o . 3,86 (1951). (60)Ibid., p. 95. (61) Zbid., p. 144. (62) Read, D., OiE Gus J.,49, No. 45,68 (1951). (63) Read, D., Petroleum Refiner,30,No. 3,130 (1951). (64) Rice, F. 0.. and Wall, L. A., J. Am. Chem. SOC.,72, 3967 (1950). (65) Roberts, R. M., and Good, G. M., Ibid,, 73, 1320 (1951). (66) Rossini, F. O.,“Reilly Lectures,” Vol. 111, South Bend, Ind., The Univ. of Notre Dame, 1949. (67) Sittig, M., Petroleum Refiner, 29, N o . 6,91 (1950). (68)Ibid., No.8,p. 99. (69)Ibid., No. 10,p. 130. (70)Ibid., No. 11, p. 125. (71) Thornton, D. P.,Jr., Petroleum Processing, 5, 601 (1950). (72)Ibid., p. 941.

Vol. 43, No. 9

(73)Ibid., 6, p. 146 (1951). (74) Uhl, W. C., Petroleum Processing, 5, 950 (1950). (75) Viland, C.K., Oil Gas J.,49, No. 30,74 (1950). (76) Viland, C. K.,Petroleum Processing, 5, 830 (1950). (77) Weber, G., Oil Gus J., 49, No. 1, 53 (1950). (78) Ibid., No.5,p. 54. (79)Ibid., No.7,p. 158. (80)Ibid., No. 13,p. 50. (81)Ibid.. No. 17.D. 54. (82j Ibid.; No. 24;-p. 60. (83) Ibid., p. 78. (84) Wilhelm, R. H.,and Valentine, S.. IND.ENQ.CHEM.,43, 1199 (1951). (85) World Petroleum, 22, No. 2,35 (1951). (86) Wright, J. F.,Petroleum Refiner, 29, No. 9, 163 (1950). RECEIYE~D June 13, 1961.

Sulfona tion and Sulfation I

EVERETT

E. GILBERT and E. PAUL JONES,

GENERAL CHEMICAL

DIVISION. LAUREL HILL RESEARCH LABORATORY, LONG ISLAND CITY, .1. Y. Manufacture of industrial sulfonates has continued to expand sharply, particularly of dodecyl benzene sulfonate detergents and sulfonated fatty oils. A n interesting technical improvement in detergent alkylate sulfonation is the proposed use of liquefied petroleum gas as a solvent. Papers continue to appear on the use of pyridine-sulfur trioxide as a special direct sulfonating agent of fairly broad applicability. A noteworthy advance in the aliphatic field is a study on direct sulfonation of aliphatic ketones. The preparation of various heterocyclic sulfonates b y an indirect procedure (aqueous chlorination of the thiol) was shown to b e more widely useful than previously known approaches. Publication of reports on German sulfonation processesup to the present time a rich source of detailed data-has begun to diminish markedly. The relative usefulness of the various compounds of sulfur trioxide in sulfonation and sulfation i s indicated in a tabulation of their frequency of use in the examples and processes cited.

I

N T H E continuation of previous sulfonation reviews by Lisk (193-226), the present study covers information on this unit process published during 1950,with some reference to earlier

work. As previously d e k e d by Lisk (223), the formation of sulfonic acids (sulfur-to-carbon bond) and sulfamic acids (sulfur-tonitrogen bond) is the subject of primary consideration. In addition, however, the subject of sulfation of olefins and alcohols has also been reviewed, because similar reagents are used, and the properties and uses of the industrially important long-chain organic sulfonates and sulfates are generally similar. A separate section is devoted to treatment of fats and oils, as this operation, referred to by the trade as “Sulfonation,” may be either sulfonation or sulfation depending on the conditions and reagent used. Although sulfonation has traditionally been thought of as involving the reaction of an organic compound with an inorganic sulfonating agent, a number of important sulfonated materials are made by reaction of a sulfonic acid with an organic compound t o yield a new sulfonic acid with markedly different properties. This type of reaction is considered under the subheading Polymerieation and Condensation under both Aliphatic and Aromatic headings. Aromatic sulfone formation, often a side reaction in sulfonation proper, is also considered briefly where it occurs a s the result of a direct sulfonation procedure. The manufacture of sulfonates has increased steadily. Production of dodecyl benzene sulfonate detergents doubled in one year, the estimated total for 1950 being over 1 billion pounds (516). The output of sulfonated fats and oils tripled during 1939 to 1947 (332). Sales in 1949 of all sulfonated and sulfated sur-

face active agents totaled 295,000,-

000 pounds, valued a t $66,000.000

(377). In the face of this increase in the volume of sulfonate manufacture, there has developed a shortage in sulfur and sulfuric acid, freight rates have increased, and governmental regulations on waste acid disposal have become more stringent. The result has been an intensification of interest in the possible use of stronger and more efficient sulfonating agents, and in improved methods of spent acid recovery and recycle. This trend was noted by Groggins (227) several years ago. Two general reviews on sulfonation were noted. One of theie (2@), discussed use of sulfur trioxide in its various forms. The second (129)briefly reviewed the manufacture and uses of industrial sulfonates.

ALIPHATIC SULFONATES This general heading covers formation of sulfonic acids in which the -SOsH group is attached to an aliphatic carbon atom regardless of the structure of the rest of the molecule. In most cases this carbon atom in the final sulfonate is saturated; in a few cases it is olefinic. Petroleum sulfonates, which undoubtedly contain some of the aliphatic type, are considered under a separate heading, as are sulfonated fatty oils. DIRECT TREATMENT WITH COMPOUNDS CONTAINING SULFUR TRIOXIDE

Saturated Parafljns and Cycloparafllns. Reaction of methane with sulfur trioxide under pressure (820 to 1350 pounds per square inch) a t elevated temperatures (230’ to 300’ C.)and using mole ratios of sulfur trioxide to methane varying from 0.59 t o 10 with and without mercury sulfate catalyst has been patented (198,169, 327) as a process for producing methanol and sulfonated derivatives of methane [methanesulfonic acid, methanedisulfuric acid (methionic acid), and their methyl esters]

.

September 1951

INDUSTRIAL AND ENGINEERING CHEMISTRY

Conversion of methane t o total reaction products is from 8 t o 44% in the examples cited. Experimental data are presented for the thermal conversion of pure methanesulfonic acid t o methanol, sulfur dioxide, and methyl methane sulfonate, leading t o the conclusion t h a t the methanol formed by direct reaction of methane and sulfur trioxide may be formed via the sulfonic acid. One mole of isohexane of undisclosed structure (prepared by dehydration and hydrogenation of the Ce alcohol from carbon monoxide and hydrogen) was 50% converted t o capillary active sulfonic acids by treatment with sulfur trioxide (1 mole) dissolved in 300 ml. of liquid sulfur dioxide a t -10' c!. No higher molecular weight reaction by-products were noted. n-Dodecane

P

R

\

*y 7" H-C-

I

O,

R

\

C=CH

/

+

"

C-H

/so, soz-0

SO,

without oxidation and therefore the reaction was concluded not t o proceed via this compound. This work has a practical bearing in connection with the acid treating of petroleum fractions (known t o contain cycloparaffins), since substantial quantities of sulfur dioxide are always formed in such operations. The pyridine-sulfur trioxide complex does not sulfonate paraffins or cycloparaffins even on prolonged heating a t 150" C. according to Terent'ev and Dombrovskii (344). Olefins and Acetylenes. This grouping includes the reaction of sulfur trioxide (as oleum or as a complex with dioxane or pyridine) with olefins t o yield an olefinic sulfonic acid or a substituted carbyl sulfate as follows:

K + \

I

2023

Hzo

R"

C-hH

/I

H OSO,H

(A)

R

I SOsH

-+

\

I

R"

C-CH +HzSO, H/I OH SOsH I

(C)

(D)

R' R

\

R"

/

C-CHSOIH

R

\

Rf

gave no reaction under the same conditions. This work was carried out by I. G. Farbenindustrie a t Frankfort (182). Of contributory interest are two papers citing attack of p a r a f f i hydrocarbons by sulfuric acid, even though sulfonic acids are not specifically mentioned as products. In one case (875)n-butane and isobutane are shown t o be absorbed by acid as dilute as 84% in the range 70 't o 75' C. while these, as well as ethane, propane, and higher hydrocarbons (from light gasoline), react with concentrated acid and oleum by reactions not clearly defined. Methane is not attacked. I n a study of the reaction of four paraffin hydrocarbons a t their boiling points in the presence of 96 and 98% sulfuric acid (.%?la), it was shown t h a t the methyl group was shifted along the chain in the case of paraffins containing a t least one tertiary carbon (2,4-dimethylpentane and 2,2,4-trimethylbutane), but no reaction occurred with n-octane or 2,2dimethylbutane. This conclusion substantiates previous work, and indicates a type of side reaction t o be expected in the sulfonation of pure para& hydrocarbons and of petroleum fractions. The inertness of straight-chain paraffins as discussed above (n-dodecane to sulfur trioxide a t - 10 O C. and n-octane at reflux with 98% acid) is in contrast to the sulfonation of polyethylene, (-CH2CH,-),, as reported in a recent patent (396). Polyethylene (100 parts finely divided, purified by reprecipitation) ia treated for 3 hours at 80" C. with 20% oleum. The washed and dried product contained 2.25% sulfur (sulfonic acid groups), plus carboxylic acid groups produced by oxidation. Reaction of several cycloparaffins (cyclohexane, dicyclohexyl, cyclohexylmethylcyclopentane, and decahydronaphthalene) has been studied a t 10" C. with 20 and 60% oleums (323). Cyclohexane yields over 1 mole of sulfur dioxide per mole reacted, and the final sulfonation-oxidation-polymerization products are similar to those derived directly from cyclohexene; the same holds for the other two cyclohexyl compounds. Decahydronaphthalene is also oxidized, the cis isomer being preferentially attacked, yielding approximately two moles of sulfur dioxide per mole reacted; the final reaction product largely comprises sulfonated and oxidized polymers of unknown composition; very little appears as naphthalenesulfonic acids. Tetrahydronaphthalene, a possible oxidation intermediate, was found to sulfonate cleanly

C=aHSOiH

The substituted carbyl sulfate, -4,may be isolated as its partial or complete hydrolysis products, C and D. Sulfonation of olefins with chlorosulfonic acid will also be considered in this section. Acetylene reacts analogously, yielding compounds of type A . Products of structure E are sometimes obtained, E" being hydrogen in this case. Reaction of olefins with bisulfites t o yield sulfonic acids, or with sulfuric acid t o yield sulfates, is discussed later under. the headings Bisulfite Reactions and Sulfation, respectively. At a reaction temperature of -10" to -15' C., treatment of 1 mole of a heptene (exact structure unspecified, made by catalytic dehydration of the Cr alcohols from carbon monoxide and hydrogen) with 1 mole of sulfur trioxide dissolved in liquid sulfur dioxide yielded a product which upon saponification (part with aqueous alkali and the rest with alcoholic alkali) gave a 95.570 yield of water-soluble sulfonates (186). The chemistry of the reaction was not discussed; presumably the product was an unsaturated sulfonic acid of structure R or E. This work was done at I. G. Farbenindustrie, Frankfort, Germany. Terent'ev (342) and Terent'ev and Dombrovskii (5'43) have studied sulfonation of various diolefins witli pyridine-sulfur trioxide (10 hours a t 100' C.). The following products mere reported: 1,3-butadiene-l-sulfonic acid (from 1,3-butadiene in 50% yield), 1,3-butadiene-3-sulfonicacid (from 1,3-butadiene in 7770 yield), 2-methyl-l,3-butadiene-l-sulfonic acid (from isoacid prene in 58y0 yield), 2,3-dimethyl-1,3-butadiene-l-sulfonic (from diisopropenyl in 5770 yield), a disulfonic acid from diisobutenyl, and what appears to be 1,3-cyclopentadiene-4-sulfonic acid (from cyclopentadiene in 42y0 yield). These compounds are of type E. Treatment of butyl or amyl vinyl ethers a t 60' to 70' C. for 8 hours with pyridine-sulfur trioxide appears to yield primary reaction products of the carbyl sulfate type (348),since hydrolysis yields acetaldehydesulfonic acid (as barium salt), as follows: BuOCH=CHz

--f

BuOCH-CH2

'

+ 2SOaHOH

0

I

soz-0

I

so1

/

-+ BuOH

+ OCHCHzSOJH + HzSOI

I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY

2024

The allyl esters of the higher fatty acids have been treated with 30 to 60% oleum to yield (after hydrolysis and neutralization ) products largely com rising the hydroxysulfonates of structure RCOOCH&HOH8H&0~Na, type D , together with smaller amounts of the corresponding ethionate, type C ( 4 3 ) . The reaction is conducted, for example, at 35" t o 40' C. by simultaneous addition of allyl ester and oleum to the reaction flask. The neutralized final roducts are useful as detergents and wetting agents. In a modif?cation of this process (141), a high molecular weight olefin-for example, 1-hexadecene or tetradecene-1s added after the primary reaction to react with residual d f o n a t i n g agent; the olefins appear in the final neutralized sodium salt probably both as sulfates and as hydroxysulfonatc formed by the carbyl sulfate reaction. Use of ethyl acetate as reaction solvent in this process gives improved results, for it inhibits attack of the ester linkage (in the allyl compound being sulfonated) by the sulfonating agent (44). By using pyridinesulfur trioxide complex as the sulfonating agent (344), camphene was converted to camphenesulfonic acid, styrene to p-styrene-sulfonic acid, and indene to indene-%sulfonic. acid. The reaction was conducted by heating in a sealed tube at 100" to 150" C. for 10 hours, using 3 moles of complex to 1 mole of hydrocarbon. The sulfonic acids were isolated as the barium salts. Under the same conditions cyclohexene and methylene cyclohexane are reported to yield the saturated product (ethionate) rather than the olefinic sulfonic acid. Treatment of p-nitrostyrene and m-nitrostyrene with dioxanesulfur trioxide in ethylene dichloride at 0" C. (Suter procedure) gave 83 to 88% and 69 to 71y0 yields of the expected correspond. ing carby1 sulfate type product with the sulfur on the terminal carbon atom (360). n-Ghlorostyrene, on the other hand, yielded only 7 to 157' of this type of product; the main product (54%) u as 2-( m-chlorophenyl)-2-hydroxyethane-l-sulfon~c acid, and the corres onding ethenesulfonic acid was obtained in a 13% yield. A furtier product (19%) was tentatively identified as 2 , 4 d i - ( m chlorophenyl)-l,4-butanesultone; no sultone was obtained when 2 moles of dioxane-sulfur trioxide were reacted with 1 mole of rhlorostyrene. The sulfonation of cyclohexene has been studied by two investigators using four sulfonating agents, Using dioxane-sulfur trioxide in ethylene dichloride suppension a t 0 " C. (Suter technique), Sperling (352) isolated as the chief reaction product cyclohexene-3-sulfonic acid, as barium salt. Some of the carbyl sulfate compound was also formed. The same author ($34) also studied the reaction of cyclohexene with acetic anhydride-sulfuric acid (acetyl sulfuric acid) Two products were isolated : cyclohexene-1-sulfonic acid and ciscyclohexanol-2-sulfonic acid, both as barium salts. The I caction is thought t o involve the usual addition of acetyl sulfuric acid t o the olefinic double bond, upon hydrolysis the cis adduct forms the alcohol, while the trans adduct yields the olefin:

\

C

/

/

4

\

+ CH,COOSO?H +

+-- $I

cis

I

Cyclohexene upon treatment for 10 hours at 100' C. with pyridine-sulfur trioxide (344),followed by steam distillation with barium carbonate, yielded the barium ethionate salt. Methylene cyclohexane behaved similarly. Treatment of cyclohexene with 20% oleum at temperatures varying from 0" to 90" C. (323) yields a mixture of products (cyclohexyl hydrogen sulfate, polymers, sulfated sulfonic acids, monosulfonic acids, and polysulfonic acids), the proportions varying with the ratio of sulfur trioxide to hydrocarbon and temperature. The only three compounds definitely identified were cyclohexyl hydrogen sulfate (34.4 to 54.1% of the total product prepared under mild conditions), benzenesulforiic acid (4.36% of total product in one case only), and cyclohexene-3sulfonic acid (small amount). The above data on the sulfonation of cyclohexene are summarized in Table I.

Vol. 43, No. 9

Table I. Sulfonation of Cyclohexene Sulfonating Agent Dioxane-SOs P yridine-SO8 Acetyl sulfuric acid 20% oleum

Principal Products Cyclohexene-3-sulfonic acid; Borne carhyl sulfate-type product Ethionate-type product Cyclohexene-1-sulfonic acid: cie-cvclohexanol3-sulfonic acid Cyclohexyl hydrogen sulfate: small amounts of cyclohexene-3-sulfonic acid and henzenesulfonic acid

1-Methylcyclopentene was found by Sperling (322) to yield 1-methylcyclopentene-5-sulfonic acid upon sulfonation with dioxane-sulfur trioxide in ethylene dichloride suspension at 0 C. No hydroxy sulfonates were noted. Use of the olefin-acetyl sulfuric acid reaction t o produce wetting agents has been disclosed in a British patent (250). Long-chain fatty amides of methallylamine (or LZr-monoalkylatedmethyallylamines) are treated with acetic anhydride and 96% sulfuric acid to yield water-soluble products of undisclosed composition. Draves' test data and foaming powers are tabulated for 21 specific compounds of this type prepared. Chemistry of the sulfonation is not discussed. A German patent application describes sulfonation of longchain olefins, in a paraffin-olefin mixture from the reaction of carbon monoxide and hydrogen, with a mixture of acetic anhydride and monohydrate acid at 0 " to 5 " C. (184). The acetic acid is removed by steaming to yield a sulfonate suitable as a household detergent. Direct sulfonation of a C17- 22 butene polymer to yield alkene sulfonic acids has been discussed in a recent patent ( I ) . The sulfonation was conducted in carbon tetrachloride as solvent in the presence of acetic acid and acetic anhydride, both of which are recoverable as acetic acid. An interesting study of the sulfonation of olefins with chlorosulfonic acid was conducted a t Uerdingen by I. G. Farbenindustrie (165). For another Farbenindustrie study of the reaction between propylene and chlorosulfonic acid, see 1950 review by Lisk (reference 61, 226). Using equal weights of diethyl ether and chlorosulfonic acid, ethylene gave no reaction even a t a high pressure, propylene added smoothly under pressure, and all three butylenes reacted smoothly at atmospheric pressure t o yield the corresponding 2-chlorosulfonic acids; isononylene reacted likewise. Hydrogen chloride was liberated from these sulfonic acids with varying degrees of ease t o yield the olefinic sulfonic acids. Significantly, the use of no solvent, or other solvents such as chloroform or carbon tetrachloride, yielded no sulfonic acid, b u t exclusively the chlorosulfonic acid organic ester. The reaction of acetylene with sulfur trioxide dissolved in liquid sulfur dioxide at -20' to -25" C. is stated (120) t o proceed as follows: O

O /-

o=s=o H C S H

+ 4SOa-+-

\\

Hc/

II\

0/0

CH

The formula of this compound, physically a viscous, molasseslike product, is basically of the carbyl sulfate type. This product has been hydrolyzed and condensed with aromatic hydrocarbons (119) to yield surface active sulfonates. Saturated Aldehydes and Ketones. The direct sulfonation of aliphatic aldehydes, a reaction not previously reported, was studied by Truce and Alfieri (359)for isobut,yraldehyde, heptaldehyde, and phenylacetaldehyde using dioxane-sulfur trioxide re-

I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY

September 1951

agent a t room temperature. Fair yields of the alpha monosulfonates [RCH(SOaNa)CHO]were obtained as sodium salts. The same authors used the same general technique for sulfonation of a series of nine ketones of various types, all of which had on the carbon atom next to the carbonyl group, an aliphatic or cycloparaffinic hydrogen which was replaced t o yield alpha monosulfonic acids. The ketones chosen t o illustrate the generality of the reactions, which gave a 70% yield in all cases but one, were as follows : acetophenone, 2-acetothienone, acetomesitylene, @-acetonaphthone, pinacolone, propiophenone, is+ butyrophenone, acetone, and cyclohexanone. Pivalophenone (containing no alpha hydrogen) did not react, as was expected.

x SEPARATOR

COOLING

9

I

1

a

0 IL-

c

SEWER

Figure I. Continuous Photochemical Preparation of Aliphatic Sulfonyl Chlorides

Ring sulfonation was not reported, except possibly to some extent in the unsubstituted ring of 8-acetonaphthone. On the other hand, only ring sulfonation was reported with 2-acetylfuran, 1-acetylpyrrole, and 2-acetylpyrrole using pyridine-sulfur trioxide, as discussed more fully later under Heterocyclic Nitrogen Compounds. The preparation of sulfonated dyes has been reported by the action of chlorosulfonic acid on cyclopentanone (274). The sulfonation of camphor, yielding camphorsulfonic acids of long standing pharmaceutical interest (as salts), continues to be the subject of investigation by Poggi (272, 375) who prepared 8camphorsulfonic acids by treatment of synthetic camphor with chlorosulfonic acid, Several organic amine salts of 8- and 10camphorsulfonic acids were prepared for physiological testing. The sulfonation of fenchone, a terpenic ketone isomeric with cnamphor, has been studied (558). None of the usual methods employed in sulfonating camphor, such as use of concentrated sulfuric acid plus acetic anhydride (acetyl sulfate), treatment xith oleum, or rearrangement of the chlorosulfonic ester were found applicable. Direct treatment with sulfur trioxide vapor, however, gave a 64.87% yield of d-fenchonesulfonic acid; a number of its derivatives were prepared. This observed difficulty of sulfonation is not unexpected, since fenchone contains no hydrogen atoms alpha to the carbonyl group as does camphor. OXIDATIVE PROCEDURES

Sulfochlorination.

Direct sulfochlorination of aliphatic hydro-

railions has continued to receive attention, for production of sulfonates from saturated long-chain hydrocarbons such as those dcsrived from Pennsylvania petroleum (236), hydrogenated Fisc.hcr-Tropsch gas oil (382), or paraffin wax (261). A critical review with 40 references has been published (594)in Russian.

2025

The mechanism of the sulfochlorination reaction was studied in relation to Kogasin (Fischer-Tropsch dist,illate still containing unsaturates and oxygen compounds) as raw material (614). Technical Kogasin could be sulfochlorinated in the dark because of the catalytic action of the olefins and oxygen compounds, whereas the specially purified material (free of olefins and oxygen compounds) required catalytic activation by addition of olefins and peroxides for the dark reaction t o occur. Several materials (pyridine, isoquinoline, aniline, cumarone, magnesium chloride, ferric chloride) were 'found to inhibit the sulfochlorination reaction, while ammonium chloride and camphor were indifferent. Reports on studies by I. G. Farbenindustrie in Germany of this reaction with propane, n-butane (169), isobutane (170), and hexadecane ( 1 8 ) have been published, as has also a study on the constitution of Mepasin (hydrogenated Fischer-Tropsch gas oil) sulfonates (16). Process studies by the same group on factors influencing disulfonyl chloride formation have also been made available (16, 177). Manufacturing directions for sulfochlorination of Mepasin t o give Mersol H have been published (43, 188), as have process details for Immergan, derived from the ClWlIs fraction and used for treating leather ( 4 2 ) . Laboratory studies on continuous sulfochlorination, as carried out by I. G. Farbenindustrie at Hachst, have been published (183). Herold et al. ( 1 4 2 ) have patented treatment of gaseous paraffin hydrocarbons containing 2 to 8 carbon atoms with sulfur dioxide and chlorine in the presence of a solvent stable to these materials; light of 1800 to 5000 A. is used. A recent bibliography of reports on German chemical industry (1,955)cites about twelve items dealing with sulfochlorination through 1948. Most of the information in these reports has already been published elsewhere. An improved continuous process for sulfochlorination with sulfur dioxide and chlorine in the presence of light has becn patented (692). A major advantage of the process, which is conducted under conditions of extreme turbulence, is avoidance of foaming in the reaction zone. An exemplified raw material is the same highly paraffiic hydrocarbon used in the azo-catalyzed process described below. This process is schematized in Figure 1 . Since sulfochlorination is not carried to completion, the product contains unreacted hydrocarbons and chlorides which m u d be separated from the desired sulfonyl chloride or sulfonate. An estimate has been published for constructing a plant in Germany for solvent extraction with liquid sulfur dioxide (88). A4ctivationof sulfochlorination by catalysts other than light has continued t o receive attention in an effort t o minimize the chlorination side reaction. In this connection, a new type of catalyst-acyclic azo compounds such as a,*'-azobidisobutyronitrile)-has bccn patented (95) for sulfochlorination of saturated aliphatic hydrocarbons with sulfur dioxide and chlorine, thus obviating the actinic light employed in the standard process. The same type of azo catalyst may also be used in sulfochlorination with sulfuryl chloride (226). However, a second catalyst, such as stearamide or a nitrogen ring compound, is added for best results. In both processes a suggested raw material is a highly paraffinic hydrocarbon free from unsaturation and boiling from 265" to 305" C. Operation is preferable a t atmospheric pressure and the products are used to make Burface active agents. Organometallic compounds (tetraethyllead or tin, triphenyl bismuth, dimethyl cadmium), triphenyl methyl, benzoyl peroxide, ascaridole, azomethane, and azopropane also are catalysts for dark sulfochlorination (252, 256). An interesting extension of the sulfochlorination reaction to di( tert-alky1)peroxides has been disclosed by Rust and Vaughan (d97), who outline the mechanism of the reaction. Di(tert-butyl)peroxide was converted by sulfur dioxide and chlorine under illumination t o a mono- and a disulfonyl chloride, which were found t o undergo the usual reactions of sulfonyl chlorides ($98). Such peroxide sulfonyl chlorides had not previously been prepared.

2026

INDUSTRIAL AND ENGINEERING CHEMISTRY

The technique of hydrolysis of the sulfonylchlorides to surface active sulfonates has continued to receive attention, as has also the recovery and purification of the sulfonates so obtained. Use of aqueous alkali metal carbonate under pressure above 100' C. for the hydrolysis has been patented (338). Unhydrolyzable material is distilled off with liberated carbon dioxide. Recovery as alkaline earth salts of the sulfonic acids which would normally be discarded in isolation as sodium salts is disclosed in a patent (71). Not only is the yield improved, but the alkaline earth salts are claimed to be good foaming and washing agents. An example is cited in which 2.5% of the total yield is recovered as calcium salt by addition of 15 weight % concentrated calcium chloride solution. Preparation of substantially salt-free sulfonates from sulfochlorination has been disclosed by Dammers ( 7 6 ) ; an organic solvent is used which is insoluble in the aqueous inorganic salt solution and contains a polar group. In an example, cyclohexanol is used with the aqueous solution of the sodium salt from sulfochlorination of a gas-oil fraction. Decolorization of the sulfonates from sulfochlorination has been achieved with hydrogen peroxide (261,264). For volume production of sulfonate detergents, German technologists preferred sulfoxidation t o sulfochlorination. However, the sulfonyl chlorides are uniquely adapted to reaction with a wide variety of the organic compounds to yield potential plasticizers, specialty wetting agents, etc. A number of these secondary products will be reviewed briefly. Sulfonylphenyl eaters (Mesamoll) have been studied as plasticizers for Igelite (polyvinyl chloride) (reference 443, 186). Esters of sulfonyl chlorides with phenolsulfonic acid are wetting agents, as are also the corresponding derivatives of 4-hydroxybenzoic acid and 4-aminobenzoic acid (181). The polyglycol esters (with or without sulfation) are also cited as wetting and emulsifying agents (181,216). Heating with low molecular weight alcohols largely causes hydrolysis to the sulfonic acid, while polyglycols, from eight or more ethylene oxide units, yield esters exclusively upon heating a t 120" C. for 10 to 12 hours in a nitrogen stream (to remove hydrochloric acid) (616). The aliphatic esters, aminoalcohol derivatives, and the anilides were also prepared (162), as were the reaction product with glycine and formaldehyde-bisulfite (172). Treatment of the sulfonyl chlorides with ultraviolet light a t 100" C. and in the absence of metals (which promote side reactions) yields the corresponding alkyl chlorides (17') with liberation of sulfur dioxide as follows: RSOzCl-

RCl

+ SO2

The alkyl chlorides so obtained are not easily prepared by alternative procedures. Pyrolysis of the long-chain sodium sulfonates (at i50° to 400" C.) yields 80 to 90% of the corresponding ole6ns (178);thus, a half-sulfochlorinated Mepasin yielded an olefin with iodine number of 120, 0.5% chlorine, and 0.2% conjugated diolefins. Attempted extension of this reaction to preparation of diolefins (from disulfonyl chlorides), which in turn might be oxidized to dicarboxylic acids useful as raw materials for synthetic fibers, led to small yields of the desired acids and the conclusion that the low yield is explainable by location of the sulfonyl chloride groups on nearby carbon atoms. Sulfoxidation. No basic improvements in this process have been noted since it was reviewed in 1948 (623),when an outline was presented of the preferred modification involving treatment of a long-chain paraffi hydrocarbon (as Mepasin, a predominantly straight-chain Fischer-Tropsch paraffi having an average of 15 carbon atoms) with sulfur dioxide and oxygen in the presence of acetic anhydride. In a second step the peracetate product is hydrolyzed with water under reducing conditions t o the desired surface active sulfonic acid plus acetic and sulfuric acid as follows: RH

+ SO2 + 02 + (CH&0)20

--t

RSOzOOCOCHa

+ CHICOOH

RSOzOOCOCHs

Vol. 43, No. 9

+ SO2 + 2H20 + RSOlOH

+ CHaCOOH + H&Od

Details of the two principal modifications of the process (lightwater and acetic anhydride) have been reported (183),as developed by I. G. Farbenindustrie a t Hochst in 1943. The anhydride process, being of most interest, is presented in some detail. Other reports have been published on process studies made a t Hochst (171, 174, 176). An excellent general review of sulfoxidation up t o late in 1949 has recently been presented by Orthner (262), who participated in development of the process for I. G. Farbenindustrie. Both principal modifications of the reaction are discussed, flow diagrams and technical details being presented. The free radical mechanism of the reaction is discussed and analogies are drawn to those other closely similar reactions of paraffis-namely, sulfochlorination, carbochlorination (with oxalyl chloride), and the reaction with phosphorus trichloride and oxygen. Eighteen references are given, most of which are to German patent applications. Although hydrocarbons are the raw materials of prime interest, the acetic anhydride technique has been extended to alkyl chlorides, ethers, ketones, and carboxylic acids as well as to their esters, chlorides, anhydrides, and nitriles, a sulfonic group being introduced in each case. I n addition t o various chain initiators already disclosed for activation of this reaction--e.g., actinic light, ozone, hydrogen peroxide, peracetic acid, etc.-Bradley discloses in a patent ( 8 7 ) the use of lead tetraacetate and tetrapropionate, diacetyl, and tert-butyl peroxide. A CIS p a r a f f i (200 parts) is treated with sulfur dioxide (186 parts) and oxygen (42 parts) in the presence of lead tetraacetate (4 parts) for 2 hours a t 60' C. to give a 16% conversion to hexadecane sulfonic acid, recovered as sodium salt. The reaction is also run in the presence of acetic anhydride, propane sulfonyl chloride, and hexadecane sulfonyl chloride. Another patent (267)discloses uses of acyclic azo compounds as catalysts, such as a+'-azodiisobutyronitrile; they are preferably used in conjunction with aliphatic acid anhydrides, chlorides, or bromides, or an aliphatic sulfonyl chloride containing 2 to 6 carbon atoms. Miscellaneous. The aqueous chlorination-oxidation procedures for the conversion of mercaptans (thiols), disulfides, isothiourea compounds, Bunte salts (sodium organic thiosulfates, RSSOsNa), and related compounds t o sulfonyl chlorides as developed by Johnson and coworkers (84,196,367),continue to find application. Thus, Sperling (323) obtained a 42% yield of sodium cyclohexane sulfonate by aqueous chlorination of the disulfide to the sulfonyl chloride, followed by hydrolysis with aqueous sodium hydroxide to the desired product. The primary reaction is as follows, R being cyclohexyl:

(RS-)z

+ 5c12 + 4H20

----t

2RSOzC1

+ 8HC1

A study has been made of the aqueous chlorination-oxidation of halogenated disulfides prepared from olefins and sulfur halides (178). Chlorination below 30" C. over a period of several hours in concentrated hydrochloric acid medium gave a quantitative yield of CICHzCH~SOzCl(2 moles) from pure (CICH2CH2S)2; (C ~ S C C H I Swas ) ~ likewise converted to the sulfonyl chlorides. Monosulfides, often obtained as by-products in the olefin-sulfur monochloride reaction, yield only 1mole of sulfonyl chloride, and attempts t o use the second group did not meet with success. Alpha chlorinated sulfides reacted sluggishly and in poor yield. Lieber and Cashman (220) have adapted a similar procedure also originally developed by Johnson and coworkers (38),involving reaction of an organic halide with thiourea followed by aqueoue chlorination to yield the sulfonyl chloride, t o the case of chlorinated para& wax, the reaction being schematized as follows:

INDUSTRIAL AND ENGINEERING CHEMISTRY

September 1951

\Vax.C1

+ IiHzCSNHa +wax - SC(:NH)NH,.HCI

+

\\-as - SC(:S€I)IiH~.HCI C11

+ H1O + wax.S02C1

The sulfonyl chlorides formed were further converted to the sodium sulfonate, the sulfonamide, the sulfonanilide, and the addition compound with pyridine. In a second patent (221), Lieber and Cashman condensed the wax sulfonyl chloride with aromatic hydrocnrhons (as naphthalene) in the presence of aluminum chloride to yield sulfones useful as lubricant pour point depressants. Aqueous chlorination of pseudothiouronium salts, mch as disclosed by Lieber, have in some cases led to explosions, and care should be taken in conducting this reaction (356, page 98). Aqueous chlorination-oxidation of Bunte salts has been used recently by Sprague (326) for preparing the corresponding sulfonyl chlorides from o-chlorobenzyl chloride, ethyl bromide, npropyl bromide, and 1-pentyl bromide. The halides were first reacted with sodium thiosulfate, then chlorinated, in aqueous medium presumably by est,ablished procedure (83). Use of nitric acid as oxidizing agent for conversion of a thioc,J.anate to the sulfonic arid has been demonstrated by Sperling (325) for the case of cyclohexene dithiocyanate. The reaction was run a t 80' C. for 1 hour using dilute nitric acid (specific gravity, 1.28) containing ammonium vanadate catalyst. The disulfonic acid was isolated as the barium salt. Proell, in continuing his studies of the oxidation of mercaptans to sulfonic acids, has patented (279) oxidation with air with a catalytic quantity of an oxide of nitrogen. The catalytic effect is enhanced by the presence of a very small proportion of water in the reaction zone. Examples are cited of the oxidation of n,dodecyl and n-butyl mercaptans in a gas lift-type reactor in the range of 50" to 120" F. The sulfonic acids produced by this general procedure contain impurities, the removal of which has been accomplished by solvent ext,raction with olefins containing between 8 and 30 carbon atoms (IOS),or by treatment with hydrogen sulfide (276); the solid sulfonate salts may be purified by thermal treatment (978). The use of such sulfonic acids (1 t o 5 carbon atoms) for preparation of electroplating baths has been patented (277). Brown has patented (45) an electrolytic oxidation process for t,he preparation of alkyl sulfonic acids (1 to 4 carbon atoms) from the corresponding disulfides, dimethyl and diethyl disulfides being specifically cited in examples. The cells may be constructed of glass or platinum and the solvent may be the sulfonic acid formed plus n-ater. Oxidation of diethyl disulfide with peracetic acid has been ehoLvn by Small and coworkers (313) to yield the thiosulfonate:

+ 2CH3COOOH+CZHk302SCzH5 + 2CI13COOI-I

(CZH,S--)2

An unusual case of oxidative sulfonation has been reported by Sperling (325),involving the preparation of cis-cyclohexanedisulfonic acid (as ammonium salt) by treatment of cyclohexene with aqueous ammonium bisulfite in the presence of catalytic animonium persulfate and of oxygen. Oxygen was absorbed, the reaction being of the following type:

\

/

/

\

C=C

+ 2SH4S03H + 0 --+

-C-

I I

1 CI

+ H20

SO,N€Id SOaXH,

The expected product was the saturated monosulfonate, which would be predicted on the basis of the work of Kharasch anti collaborators (906), and this \vas the major product isolated at pH 5.4. However, no monosulfonate was formed a t p H 3.9 or 2.2, although fair yields of disulfonnte were isolated in both cases. The oxidation of an aliphatic mercapto group to the correFponding sulfonic acid with barium permanganate in aqueous acetone medium at ice temperature has been reported by Hofmann ( 1 4 6 ) . The specific compound oxidized was dl-hexahydro-2-0~0-

2027

l-furo-(3,4)-imidazole-4-(pentanethiol). The heterocyclic portion of the molecule was not attacked under the conditions used. BISULFITE REACTIONS

Addition to Olefinic Compounds. An improved process for the addition of aqueous bisulfite-for example, the ammonium salt-to olefinic hydrocarbons (I-octene, 1-decene, 1-dodecene, 1tetradecene, and 1-hexadecene) has been patented (153). Better yields are obtained by using suitable solvents (alcohols and amines) in conjunction with certain organic peroxides which promote the reaction but do not extensively oxidize the bisulfite t o bisulfate. The addition of ammonium bisulfite to cpclohexene in the presence of catalytic ammonium persulfate and oxygen has been studied by Sperling (325). The expected product, the ammonium salt of t,he saturated monosulfonic acid, was obtained a t p H 5.4. However, a t pH 3.9 or 2.2 none was formed, the major product being the disulfonate. The addition of sodium sulfite to tetrafluoroethylene has been described (64). The reaction was run in aqueous solution a t 120" C. for 9 hours a t 350 pounds per square inch pressure in a silver-lined autoclave to give a good yield of the corresponding sodium sulfonate. This in turn was converted to the sulfonic acid and t,o the sulfonyl chloride. The addition of sulfurous acid to crotonaldehyde to yield butyraldehyde-3-sulfonic acid has been utilized as an intermediate reaction for the manufacture of tanning agents by further condensation with catechol and formaldehyde (376). The reaction which is carried out with cooling and in the absence of air is as follows, the product being isolated as the bisulfite addition compound (hydroxysulfonic acid): CHsCH=CHCHO

+ 2S02 4 2H20 ---+ CHICH(SOjH)CH?CH(0H)SOJH

The addition of sodium bisulfite to several maleate esters to form the corresponding sulfosuccinic esters has been disclosed by Lynch (229). In a typical example, the maleic ester (from maleic anhydride gnd 2-p-tert-butylphenoxyethanol) was refluxed for 17 hours with a solution of 31.5 parts of sodium bisulfite dissolved in a mixture of ethyl alcohol (150 parts) and water (35 parts). The reaction mixture was filtered and evaporated to dryness to obtain the desired product,. .4dditional examples are given using phenoxyethyl esters with varied alkyl groups in the bmzene ring. Gold, in continuation of his study of the preparation of niLrosulfonic acids (123, 194), discloses the addition of bisulfite to nitro-olefins. In specific examples, nitrorthylene, 1- and 2-nitroare repropene, 2-nitro-l-butene, and 2-phen,vl-l-nitroethylene acted with aqucous sulfites and bisulfites at betwecn 15' and 40" C. to give 70 to 88% yields of the desired sulfonate?. The salts were converted to the free acids and other salts by ion exchange, and were reduced to the corresponding aminosulfonic :icids. I n the case of nitroethyiene, the addition reaction is:

SII,HSO~

+ cIi2=cI-rso2--+N ~ r , o J s c ~ m m o 2

Vinylpyridiries (the 2- and 4-isomcrs are cwniplified) have been shown to add sodium bisulfite or sulfurous acid t o yicxld t h e corresponding sulfonic derivatives ( 5 7 ) . The reartion may be conducted in ethyl alcohol-watcxr nicdium by heating ;it 50 O to 60" C. The sulfonic group is on the terminal carbon. Substitution Reactions. The preparation of soilium ethane sulfonate by the reaction of ethyl iodide with sodium P u l f i t r : ha3 been described ( 1 1 7 ) . The sodium sulfonate wits then convc,rtcd to the sulfonyl chloride with phosphorus pentachloride. The preparation of sodium bromoethane su1fonat.e from t,thylene dibromide (4.95 moles) and sodium sulfite (1.5 molrs) has been reported (264); 413 gram3 of crude dry salts were obtained, which with phosphorus pentachloride (1.1 moles) yielded 65y0 of 2-bromoethane sulfonyl chloride.

INDUSTRIAL AND ENGINEERING CHEMISTRY

2028

Ethylene dibromide and sodium sulfite heptahydrate (in 1 t o 2 molar ratio) were refluxed for 3 hours with theminimum quantity of water required t o dissolve the sulfite (299). The reaction mixture was evaporated t o crystals, and tbe solid obtained dried at 120" C. The yield of 1,2-disulfonate was 75'35, 1,4Dibromo-2-butene has been converted t o the corresponding disulfonate (201), presumably by reaction with sodium sulfite, by the following reaction:

Val. 43, No. 9

cases. I n such reactions, sulfomethylation H i usually accompanied by resinification of the phenol-formaldehyde type; mixtures of phenols are often used to modify the properties of the product.

Exam les of the practical use of sulfomethylation of monohydric pgenols in the preparation of tanning agents have been published (376). I n one case, cresol (320 kg., grade uns ecified), 30% aqueous formaldehyde (260 kg.), and crystallieel sodium sulfite (200 kg.) were heated for 8 hours a t 100" C. I n a second example, a mixture of phenol oil SR 1 (375 kg.) and cresol D A B BrCHtCH=CHCHZBr 2NazS03---+ IV (375 kg.) was heated with 30% a ueous formaldehyde (632 N ~ O ~ S C H Z C H = C H C H ~ S O ~ Nkg.) ~ and crystallized sodium sulfite 7640 kg.) for 7 hours at 100" C. I n a third case, a mixture of cresol DAB I V (311 kg.) and @-naphthol(34 kg.) was heated with 30% aqueous formaldehyde Sperling (322) has prepared cyclohexene-3-sulfonic acid (as (282 kg.) and sodium sulfite (215 kg.) for 8 t o 10 hours at 100' C. barium salt) by reaction of 3-hromocyclohexene with aqueous The sulfomethylated reaction products are processed further t o ammonium sulfite by heating 4 days in aqueous solution on the yield the desired tanning agents. steam bath, followed by treatment with barium hydroxide. The Combined sulfomethylation and resinification of phenol by a n im roved procedure (preparation in the presence of no more than yield was low. 4081, water and curing above 100" C.) yields ion exchange resins Cyclohexanesulfonic acid was prepared in 9.4% yield by Sperof su erior roperties (78). ling (383). Bromocyclohexane was refluxed with aqueous SuPfometKylation of alkylated monohydric henols (with one ammonium sulfite. or more side chains-for example, metapentagcyl derived from Several ketone alpha sulfonates were prepared (369)by heating cashew nut oil), followed by conversion of the sodium salt t o the barium, lead, or zinc salt, has been atented (136) as a method the corresponding alpha bromo compounds with aqueous sodium of roducing metal sulfonate-type luiricant additives. sulfite. Sulfonates of the following ketones were thus prepared: &her phenols have also been sulfomethylated to roduce acetophenone, acetothienone, acetomesitylene, pinacolone, protanning agents and ion exchange resins. Thus, 4,4'-dihyd)roxydipiophenone, and isobutyrophenone. These ketone sulfonate8 ghenylpropane (280 kg.), obtained from henol and acetone, has een heated 8 hours at 80" t o 90' C. w i g 30% a ueous formalwere also prepared by direct sulfonation with dioxane-sulfur dehyde (250 kg.), water (910 kg.), and sodium. s&ite (260 kg.) trioxide. as an intermediate step in preparing a tanning agent (376). The same type of reaction has been used recently t o prepare Similarly, Day and D e Hoff (80) prepared ion exehange resins ketone alpha sulfonates soluble in lubricating oils (810,386, 387). from 4,4'-diphenylol dimethyl methane, formaldehyde, and sodium sulfite by combined resinification and sulfomethylation, Examples are given of the reaction of chloromethyl ketones using a referred 5 t o 1 molar ratio of aldehyde t o phenol. Like(made by the Friedel-Crafts reaction of chloroacetyl chloride wise, di$droxydiphenyl sulfone (720 kg.), prepared from phenol with aromatic petroleum fractions) with aqueous alcoholic sodium and sulfuric acid, sodium sulfite (330 kg.), water (1490 kg.), and sulfite at 300 O F. for 15 hours under pressure t o yield 8674 of the 30% aqueous formaldehyde (460 kg.) were heated 30 hours at 150" t o 155" C., the formaldehyde being added in two equal porcompound RCOCH2S03Na. Similar examples are cited for p t i o n s - o n e at the start and the other 12 hours later. By a similar octadecylphenacyl bromide (refluxing for 9 hours at atmospheric rocedure the sulfone from m-cresol was sulfomethylated by pressure), and for a-chloro-p-laurylacetophenone. The sodium feating for 6 hours at 105" C. salts were converted t o other salts, calcium in particular, for use In contrast t o the above sulfomethylated sulfones which are water-soluble, D a y ( 7 9 ) found t h a t use of 5 t o 1 molar ratio of as lubricant additives. formaldehyde t o 4,4'-dihydroxydiphenyl sulfone yields a waterSulfide-sulfonates suitable for use as detergents may be preinsoluble sulfomethylated resin suitable for use in ion exchange. pared (10,9)by reaction of an olefin (a Cwlo olefin made by phosSulfomethylation of amines is also a well-known reaction. I n phoric acid-catalyzed polymerization of a (33-4 o l e k is cited) a recent example (314), dicyandiamide (84 grams) is added over a 10-minute period t o a mixture of formaldehyde (30 grams in 60 with sulfur monochloride, followed by refluxing with aqueous grams of water) and sodium bisulfite (104 grams in 221 grams of sodium sulfites. The reactions involved are in part as follows: water), then heated t o 60" to 70" C. for '/z hour and finally t o 75" hour. The product has the structure NCNHCto 95" C. for PRCH=CHz SzClz [RCHClCHzIzS S ( :NH)NHCHzSOsNa. [RCHClCHZlzS 2Na2S03--+ [RCH(SOsNa)CH2]zS 2NaCI o-Anisidine has been sulfomethylated on a manufacturing scale at Leverkusen (373). The amine is added t o aqueous formaldeWork has continued on the preparation of metallic sulfonates hyde-sodium bisulfite at 70" t o 80" C. t o obtain a 95% yield of the desired product. by nitrosation-sulfitation of olefins (treatment of olefins with Substitution of acetaldehyde for formaldehyde in the sulfonitrosyl chloride or related, materials followed by treatment with methylation reaction has been disclosed in a recent patent sulfite to obtain a mixture of sulfonates). A patent has been (110) for the case of a primary amine. In a n example, sodium issued on preparation of the polyvalent metal salts, such as bisulfite (31.2 grams), acetaldehyde (17.3 ml.), and 2-butoxy-5aminopyridine (50 grams) were mixed and heated to 60' t o aluminum, copper, cadmium, zinc, etc. (1Q.2). The process in75" C. to obtain the following reaction: volves treatment of a solution of the alkali sulfonate with a water-soluble salt of the polyvalent metal. RNHz CH3CH0 N ~ H S O ~ + R N H C H ( C H I ) S O ~ Nf ~ H20 Sulfomethylation. Sulfomethylation, involving replacement of an active hydrogen with the -CH4S03Me group by reaction of Sulfomethylation of long-chain fatty amides, cited in a previous review (reference 309, 223), was studied by I. G. Farbenthe appropriate compound (phenols, ketones, amines, amides) industrie at Hochst in 1938 (162) from the standpoint of ossible with formaldehyde-sodium bisulfite, has been shown by Suter manufacture. Oleic amide was reacted with formalfehydeand coworkers (337) to be widely applicable. The reaction may sodium bisulfite by heating a t 155" C. The product, described be summarized in the cases of phenol and of an amine as follows: as yielding a n excellent foam, has the structure RCONHCH, S03Na. This reaction was originally developed in Japan by Oda. CeHoOH CHZO XaHS0$-+HOCeH4CH2SOaNa, HzO Miscellaneous Rea *tions. A recent patent (800) cites examples RKH, CH,O XaHSOs --+ RITHCH2S03Na H20 of the preparation of the sodium, potassium, and triethanolamine bisulfite addition compounds from chloral. The reactions are Sulfoalkylation, involving introduction of groups higher than conducted in aqueous medium and yields of the expected a-hymethyl-e.g., sulfoethylation-by use of other types of reagents, droxy-p-trichloroethyl sulfonates are quantitative if the temperais discussed later under the heading Condensation Reactions. ture is kept below 50" C. at all stages (preparation, drying, storThis reaction has been used extensively, particularly in Germany, for the manufacture of ion exchange resins (217) and synage). The products are used as herbicides. Sperling (324) has reacted cyclohevene oxide with sulfites t o thetic tanning agents, the R group being phenolic in both of these

+

+

+

*

+

+

+

+ +

+ +

+

+

+

INDUSTRIAL AND ENGINEERING CHEMISTRY

September 1951

yield the expected cis-cyclohexanol-2-sulfonic acid, isolated as barium salt. No experimental details are given except analysis. Propionaldehyde was reacted with ammonium bisulfite to yield the expected 1,l-aminopropanesulfonicacid (239). Petersen (169)has noted a reaction between isocyanates and sodium bisulfite probably as follows:

RSCO

+ P;aHS03 +RNHCOS03Na

Several isocyanates appeared to undergo this reaction, including 6-chloro-n-hexyl, octadecyl, cyclohexyl, carboethoxymethyl, as well as several diisocyanates (including hexamethylene diisocyanate), aromatic isocyanates (including phenyl), and one diisothiocyanate (trimethylene). Further work is required to establish definitely the chemistry involved in formation of these addition compounds. POLYMERIZATION AND CONDENSATION REACTIONS

This category comprises sulfonic acids prepared from other sulfonic acids, either by polymerization of an unsaturated sulfonic acid, or by reaction with other organic compounds. Usually the new sulfonic acid has different physical properties from the starting sulfonic acid. Polymerization. Production of colorless polymeric vinyl sulfonic acids by polymerization of the monomer in the absence of oxygen has been patented (196). I n an example, vinylsulfonic acid, not exposed t o air, is polymerized by ultraviolet light a t 40' C. Peroxide catalysts may be used as long as no oxygen is evolved during polymerization. Copolymerization of vinylsulfonic acid (ethylenesulfonic acid ) and N,N'-methylenediacrylamidehas been disclosed by Dudley (84) in a process for producing improved ion exchange resins. In examples, relative proportions of the two monomers vary from equal weights of each to four weights of vinylsulfonic acid to onc of the amide. Sulfoalkylation. Sulfomethylation (with formaldehyde-bisulfite) was discussed above under the heading Bisulfite Reaction. Beta sulfoethylation is accomplished by reacting a compound containing a reactive hydrogen atom with a salt of isethionic acid as follows, in the case of an alcohol or phenol:

ROH

+ HOCH2CH2S08Na-+ ROCH2CH2S03Na+ H 2 0

Sodium chloroethane sulfonate is sometimes used:

RONa

+ CICHZCH2S03Sa

ROCH2CH2S03Na

+ SaCl

Recent patents (150, 151) disclose use of this reaction with sodium isothionate where ROH is an alcohol or phenol. hlcohols include those derived from coconut oil, n-octyl, octadecyl, the secondary alcohol resulting from the addition of water to dicyclopentadiene, and alcohol ethers from the condensation of phenols with ethylene oxide. Reactions with diisobutylphenol and with two glycols are also cited. Sodium hydroxide is used as catalyst, and the reactiou is carried out by heating several hours a t about 200' C. Hollander has disclosed (149) an analogous process where R H is a mercaptan or thiophenol. Examples are given for several mercaptans [tert-dodecyl, n-octyl, substituted phenoxyethyl, hexadecyl (from kerosene), terl-tetradccyl, and benzylj, and for two thiophenols (mixed a- and @-naphthyl,and p-thiocresyl). Reaction conditions are generally the same as for the oxygen analogs. The products are used as wetting and dispersing agents. I n the case of the mercaptan and thiophenol derivatives, the same products have previously been prepared by an alternative procedure (185, 562) involving first reacting the thiol with acetylene to yield the vinyl thio ether, followed by addition of m e t a l k bisulfite. Sulfoethylation of starch using sodium chloroethane sulfonate to produce a water-soluble product has been disclosed in a 1941 German patent application by Kalle and Co (282). In an euample, starch (280 grams) was treated with methanol (500 ml.),

2029

aqueous sodium hydroxide (260 grams of 50% solution), and water (90 rn].). The mixture was heated 1 hour a t 50" C. and then reartcd with sodium chloroethane sulfonate (190 grams) a t 20" C. The sulfoethylation of several organic amines (isohexyl, isoheptyl, n-octyl, a-ethylhexyl) with sodium chloroethane sulfonate by heating for 24 hours a t 115" to 120" C. was studied by I. G. Farbenindustrie a t Hochst in 1938 (162), toward preparation of ~V-alkyl taurine derivatives. N-butylamine yielded a similar product by heating with. sodium isethionate under pressure at 200" C. Reductive alkylation of taurine was also used successfully to prepare these X-alkylated taurine derivatives. aEthylhexaldehyde gave a 91.370 yield in this reaction. Sulfoalkylation wit,h groups higher than ethyl-i.e., propyl, butyl, amyl, hexyl-has been accomplished by reacting various EUItones with other organic compounds containing reactive hydrogens (139). The renetion is typically as follows with butane sultone and a sodium alcoholate: ROSa

+ CH,CIIZCH&H, +ROCH2CH2CH2CHBSO3Sa

A

I

so2

The reaction was found widely applicable to alcohols, phenols, thiophenols, amines (also ammonia and amides), organic acids, alkali cellulose, and several inorganic compounds (postassium iodide, potassium bromide, potassium fluoride, potassium cyanide, and others). Sultones uscd included, besides butane sultone, the propane, isopentane, isohexane, and tolyl analogs. Of possible practical interest are the oleic acid and cellulose derivatives of butane sultone; the former has excellent detergent properties and t,he latter, while still maintaining its fibrous properties, dissolves in water yielding viscous solutions. The reaction generally involves simple heating of the sultone with an alkali metal salt of the other compound, or, in the case of amines, with an additional mole of the amine to form the sulfonate. Butane sultone, actually a mixture of butane and methyl propane sultones, has been prepared by the same author by direct sulfochlorination of 1chlorobutane, followed by hydrolysis of the sulfonyl chloride to the sulfonic acid, and thcmial removal of hydrochloric acid to yield the desired product (22'dj 225). Miscellaneous Condensation Reactions. The condensation of acetaldehydedisulfonic acid [OCHCH(SOJI),] with alkyl benzenes to yield products with surface activity has been patented ( 1 1 9 ) . In esamples, hydrocarbons used were ethylbenzene, secondary butylbenzene, amylbcnzenes, and isooctylbenzene (from benzene and diisobut'ylene); the acetaldehydedisulfonic acid was used in the form of the monohydrated dipotassium salt or as the acetylene-sulfur trioxide reaction product (180),and sulfuric acid was used as the condensing agent a t 0' to 33" C.

AROMATIC SULFONATES The second supplement of Beilstein's "Handbook of Organic Chemistry" covering the literature on aromatic sulfonic acids from I920 to 1929, inclusive, has been published. Some general references of recent date are also included (88). DIRECT TREATMENT WITH COMPOUNDS CONTAINING SULFUR TRIOXIDE

Monocyclic Compounds. UEKZESE. hIanufacture of benzenesulfonic acid (as a phenol intcrnicdiate) by "a manufacturing process in current use" has been described (loo),toacther with a flow diagram, equations, over-all yield to phenol, raw materid rcquirements, and details for conversion to phenol by fusion. Comparative data are also presented for preparation of phenol by three chlorobenzene hydrolysis procedures and by direct air osidation of benzene. The sulfonation process described is the Tyrer procedure involving azeotropic removal of water a t 150" C. by passage of vaporized benzene into 66' 1315. sulfuric acid; no further details of the sulfonation step are given. In reviewing the comparative merits of the various processes for

2030

INDUSTRIAL AND ENGINEERING CHEMISTRY

producing phenol (100, pages 485-6), it is concluded that the sulfonation process is being gradually replaced even though i t requires the least plant investment. Forty per cent of the total United States production in 1947 was made by the sulfonation process. The only sulfonation processes remaining today are in large plants which have long been amortized, and where the producers also manufacture the raw materials. The Monsanto process for sulfonation of benzene (for production of phenol) with oleum by a continuous 6-unit cascade system has been described (205). Although detailed reaction conditions are not given for the sulfonation step, a comprehensive discussion is presented, largely from the engineering standpoint, of conversion of the sulfonic acid to phenol by fusion. Economic considerations are also discussed, as are competitive manufacturing processes. Information on German phenol production by the sulfonationfusion process continues to appear. Data have been published supplementary to the comprehensive report on various German phenol processes cited in an earlier sulfonation review (294, 391, 392). A recent report details the German sulfonation-fusion process as operated as late as 1946 by I . G. Farbenindustrie a t Leverkusen (1f3). Benzene (1500 kg.) is .dded with cooling t o monohydrate acid (3800 kg., 200% of theory) over a period of 1 hour such t h a t the temperature rises quickly t o 60" C., then to 75" C. as more benzene is added continuously. This latter temperature is not exceeded as the remaining benzene is added. The reaction mixture is heated to 105" C. over a period of 1hour by admitting steam to the kettle jacket, and is maintained a t this temperature for 4 hours. The excess sulfuric acid is removed as gypsum. Further information includes a description of the cast iron sulfonators, neutralization in three stages, sodium bisulfite concentration in two stages, caustic concentration, fusion, quenching, sulfite filtration, acidification, rectification of crude phenol, and raw material requirements. The three benzene sulfonation processes detailed above (two American and one German) all use different strengths of acid and different operating procedures. Japanese work on benzene sulfonation for phenol includes presentation of a process flow sheet (14) and two patents. One patent (207) describes treatment of benzene with oleum to a final sulfuric acid strength of 85%, followed by treatment with vaporized benzene in the range 120' to 180" C. to complete reaction. The second patent (396) discloses neutralization of sulfuric-free sulfonic acid with excess sodium sulfite, followed Ly steaming a t 450" C. t o form phenol; the same process may be applied to production of cresols from toluene. A detailed study of the rate of sulfonation of benzene, cited in the previous sulfonation review (286), and formerly available only as a microfilm, has been published ( 7 2 )in a journal article. The disulfonation of benzene is of increasing industrial interest in the United States as an intermediate step in the manufacture of resorcinol, an important raw material for adhesives, resins, pharmaceuticals, and dyes. German manufacturing practice for this product is therefore of considerable interest (8, 7, 30). Figure 2 shows the flow system beginning with benzene, as operated by I. G. Farbenindustrie a t Hochst. The monosulfonation required 10 hours a t 50" to 100" C.; the disulfonation cycle took 61/* to P / ?hours a t 30' to 85" C. Production of synthetic cresols from toluene by sulTOLUENE. fonation and fusion is stated (9) to be under current consideration by several American companies. Details of German processes for sulfonating toluene a t Hochst in 1944-45 have been published ( 9 ) . One process produces the mixed isomers by a Tyrer-type process, while the other process yields the para isomer substantially ortho-free. To produce the mixed isomers, toluene (1035 kg., 50% excess) is added to monohydrate acid (735 kg., 7.5 moles) a t 40' to 50' C.

Vol. 43, No. 9

The mixture is then heated to 100" t o 110" C. for 3 to 5 hours, after which the azeotropic removal of water is carried out by distilling the toluenewater mixture for 25 to 30 hours with return of the distilled toluene, somewhat less than the theoretical 135 liters of water being removed. The excess toluene is next removed by heating at 120" to 130' C. for 5 t o 7 hours. The reaction mixture is cooled to 80" to 90" C. and 135 liters of water are added to yield the crystalline toluenesulfonic acid monohydrate (1450 kg.) in 93% yield, with a sulfuric acid content in the product under 0.2%. To obtain the para isomer, toluene (736 kg.) is treated with monohydrate acid (1030 kg.) at not over 108" C.; additional monohydrate (570 k ,) is then added rapidly. The reaction mixture is next heateffor 6 hours a t 116' to 118" C., and is then poured into 60" BB. acid (3200 kg.). Water (864 liters) is added at 70" to 75" C., a t which temperature the solution is clear. To separate the ara isomer, which is practically insoluble a t 20" C. in acid of t f i s strength, the mixture is cooled slowly to that temperature. The separated crystals are centrifuged 6 hours to remove most of the mother liquor. The product so obtained comprises the monohydrate as light gray crystals in a yield of 1075 to 1100 kg. (100% basis), 78 to 79% of theory. The crystals still contain 4 t o 5% sulfuric acid.

DETERGENT ALKYLATES. Sulfonation of the so-called dodecyl benzene (benzene monoalkylated with polypropylene or chlorinated kerosene) to produce sulfonate detergents has expanded steadily. Production in 1950 doubled over 1949 (315),the 1950 total being estimated a t over 1 billion pounds. Developments in this field to date have been generally reviewed (2.41). I n Figure 3 is shown a complete pilot plant for the study of detergent alkylate sulfonation. The full cycle is included from weighing-in of raw materials to production of the dried sodium salt by drum drying. Details for sulfonation of one commercial brand of detergent alkylate have been published by Kircher (208) using 20% oleum, Directions are also given for conversion of the sulfonic acid t o final products of 40% and 80 to 85% activity. Process variables are also discussed, the data on the relationship between strength of sulfonating acid and required time and temperature being presented in tabular form. Data are also presented for effect of aging time on the color of an alkylated toluenesulfonic acid. A comprehensive industrial bulletin has been published by the manufacturer of another detergent alkylate (261). Sulfonation process details are given for use of 98 and 100% acid, for 22% oleum, and a 15% solution of stabilized sulfur trioxide dissolved in liquid sulfur dioxide as solvent. Color charts are included and the relationship of process variables (acid strength, temperature, time) to color of product are shown. Other factors discussed and illustrated are: neutralization methods, bleaching and compounding, production of final products of 40 to 98% active ingredient content, equipment costs for sulfonation, neutralization, and drying, and analytical procedures. McCutcheon (230)states that commercial dodecyl benzene may be sulfonated on a laboratory scale with sulfur trioxide vaporized from commercial stabilized liquid sulfur trioxide. While the process has not been developed completely, it appears workable, a high quality product can be made, and there appears to be definite possibilities for continuous operation. Use of inert paraffinic hydrocarbons-e.g., propane, butanea8 combined solvents and refrigerants for sulfonation of detergent alkylates with oleum of a t least 30% strength has been disclosed (301,378,379). Examples are given of the sulfonation a t 0" C. in n-butane solution with 65y0 oleum, of toluene alkylated with propylene tetramer, and of sulfonation by the same procedure of benzene alkylated with hexylbicycloheptane (from cyclopentadiene and I-octene) t o yield a product with "approximately the same washing efficiency as sodium laurate." I n view of the cheapness and increasing availability of liquefied petroleum gases, this process would appear t o be the most promising of the solvent sulfonation procedures proposed to date. Their low boiling points facilitate recovery and provide self-refrigeration during sulfonation; in addition they are noncorrosive

INDUSTRIAL AND ENGINEERING CHEMISTRY

September 1951

EVAPORAR 1

STORAGE T A N K a

SULFONATOR

0

LIME-OUT TANK@

a m

w +

SAND FILTER

0

RECEIVER

a

ACIDUL ATOR

a

STORAGE TANK

DRUM DRIER

0 @

BLOW EGG

v

@'

FILTER

Q

203 1

MANUFACTURE O F L N T O+_

_____ RESORCINOL C O N S U M - E L Benzene Monohydrate Acid Oleum - 6 5 % Sal1 c a k e

Lime S o d a Ash

Caustic soda Muriatic Acid Ether Charcoal

0.9 N . 1 2 N.T 3 I k.?. 1.5 N . ? 34 N T 02 N T 2 2 N T 43 N T

z

0 00 00 5 4 N TT

-0

~ RECOVERY OF _BY-PRODUCTS _ DlSALT S T O R A G a

C-J

Gypsum

~

Sodium S u l f i t e

G I 0MELT K E T T L E

6 . 5 N.T. 1.60 N . T

REACTIONS INVOLVED

@

M o n o s u l f ona tion :

Disulfonotion:

COOLING 8 @ NEUTRALIZING

FILTER

a*

FILTER

RECEIVER

06, @

0-

RESORCINOL TO SALE

@ CRUSHER

MANUFACTURE OF

RESORCINOL

HOCHST WORKS - 1 . ~ . FARBENINDUSTRIE

Figure 2

and substantially odorless. Hazard from fire and explosion are, however, serious problems which most detergent manufacturers are not prepared to meet with present equipment. Sulfonation procedures for various detergent alkylates are cited in examples in pat,ents concerned primarily lvith improved methods for preparing the alkylate or the final neutralized product, Thus, sulfonation of alkylates prepared by improved methods from chlorinated kerosene fractions is cit,ed (101, 304). Sulfonation of a benzene alkylate made from purified FischerTropsch olefins (predominantly 1-olefins with little branching) is disclosed (69). Improved processes for preparing detergents by sulfonation of benzene alkylated with olefins from petroleum cracking are described (267, 268). Sulfonation of toluene alkylated with polypropylene ( Ci?average) is cited in another patent (381), while sulfonation of alkylated benzenes prepared from modified propylene polymers is disclosed in two patents ( 6 0 , b l ) . A German patent application describes sulfonation of an alkylate prepared by the Friedel-Crafts reaction from benzene and chlorinated paraffins (from carbon monoxide and hydrogen), the alkylate being purified by distillation to a definite refractive index (184). Benzene (also naphthalene and phenol) has been alkylated with the straight-chain secondary alcohols (made by ketonization and reduction of butyric, caprylic, or caproic acid5 j and then sulfonated at, 30" to 40" C. with either chlorosulforlic acid or oleum (291). A decy1 Tetralin mixture (130 grams) prepared by alkylation of naphthalene and reduction of the product, has been sulfonated with monohydrate acid (98 grams) a t 25' to 35' C., finally raising the temperature to 50" to 55" C. for 2 hours (282). The sulfonate is probably a mixture of the txvo isomers arising from reduction, on the one hand of the alkylated portion

and on t.he other hand of the unalkylated portion of thc naphthxlene ring system. Production of surface active sulfonates of ininiriiurii sultate content is of continuing intereut. Il(~pe:ittxIextr:iction with concentrated hydrochloric acid of an :ilk?-latcd benzcneaulfonic acid (C,,-IS side chain) or n dibutylnnphlh:il(~nerulfonic~ acid, i'ollo\ved by air blowing of the treated ~ull'onicxCid to rc~novcresidual hydrochloric axid, reduced the sulfuric wid in the first casc i'roni 3.7% to 0.2 to 0.4% (151). Extraction with a polar organic solvent--e.g., octyl alcohol-yields a su1ist:intinlly s:ilt-fi,erl sulfonate, according t o a recent patent (?5). hIIsCELL,4XEOES ALKYL.4TED I3 I.: s JC I I Y DRO C A R BO x b , Thc sulfonation of p-xylene with concentrated sulfuric acid has been recommended as suitable for a student 1:iborntory preparation (588). The sulfonation of cuinene (0.75 mole) with 9570 arid mole) for 3 hours on the st,enm b:ith has been d w c r i b d ( I O the first step in the preparation of p-isoi)rop\,lI)ht,ii~lon a Iiiboixtory scale by the sulfonation-fuiion proccdurc~. The yivlil of purified product was 35% biisctl on cuiiient'

Pseudocumene (1,2,4-trimrthylben ne), 400 k g . , \vas SUIfonated commercially in Germany ($ ) t)y addition at 75" t o 80" C. to 95C'C acid (1300 kg.) prehc~atetito this tempcriiturc,. The reaction mixture v a s stirred for 1 hour a t 80" C . . anti watcr (120 liters) was added a t this tomlx~raturc. Thc, ilrsirc~isulfonic: acid (sulfonic group in the 5 position) c.ryqtallizcd f r o m the 82 sulfuric acid mother liquor upon qtandiiig 12 hours at 20" ( and was filtered. The yield was 900 kg. of 70:; 1)roduc.t (94 of theory). The same crystallizat ioii ttx,hnique \vas u d to isolate p-toluenesulfonic acid. as desc.ril)ed above.

INDUSTRIAL AND ENGINEERING CHEMISTRY

u)32

Preparation of ion exchange resins by sulfonaPOLYSTYRENE. tion of polystyrene continues to be of interest. Manufacture and composition of several leading resins has been reviewed in a Russian article (880). Details of a laboratory preparation of such a resin based on the procedure of D'Alelio (7'4)have been published ( 1 3 1 ) . Styrene was copolymerized at 80' C. for 18 hours with about benzoyl peroxide being employed as catalyst. The copolymer was sulfonated with concentrated sulfuric acid at 100" C. for 8 hours using 1% silver sulfate as catalyst. The maximum capacity of the roduct (5.25 meq. of base er gram of the dry hydrogen form7 was independent of parti3e size and agreed with the value calculated for a monosulfonic acid. The material was hydroscopic and the dry hydrogen form absorbed approximately 80% water at 20" C. On conversion from the wet hydrogen form to the wet sodium form a decrease in volume of 6 to 7% wm observed.

10% divinylbenzene, 1%

The D'Alelio process, while yielding products of good cationabsorptive capacity, is stated ( 3 6 ) to give only with difficulty a high yield of resin in the form of stable granules of sizes and physical form well adapted to the usual ion exchange processes. This difficulty is overcome partly by producing the polystyrene in spheres, and partly by swelling the copolymer with a n organic solvent prior to sulfonation to permit ready penetration of the sulfonating agent. I n an example, tetrachloroethylene is used as the organic swellhg agent and the sulfonation is carried out using 98% acid in the proportion of 5 parts t o I part of copolymer. Production of water-soluble sulfonated polystyrenes is the subject of two patents (81,92). The sulfonations are conducted in ethylene dichloride solution a t -20" to +15' C., using coordination complexes of sulfur trioxide with dioxane in one case and bis(p-chloroethyl) ether in the other. By varying the ratio of sulfur trioxide t o polystyrene and the complexing agent, it was possible to introduce 0.5 t o 1.7 sulfonate groups per styrene unit. The products give clear, viscous, nongelatinous water solutions which may be used as sizing agents, protective colloids, tanning agents, etc. Sulfonation of a styrene-maleic anhydride copolymer to yield a water-soluble tanning agent has been described (128). The copolymer (75 parts) was suspended in ethylene dichloride (600 parts), and a solution of chlorosulfonic acid (33 parts) in ethylene dichloride (62.5 parts) was added over 1 hour without cooling but with vigorous agitation, the temperature being about 34" C. Filtration and drying yielded a solid (125 parts) which was watersoluble and well suited for tanning leather to yield a light colored product. These products are of particular PHENOLIC DERIVATIVES. importance in industrial production of tanning chemicals and ion exchange resins. In a recent patent (96) phenol (100 grams) and 98% sulfuric acid (100 grams) are heated l / z hour a t 95" C. to effect sulfonation, after which the reaction mixture is neutralized and further reacted with phenol and formaldehyde under specified conditions t o yield improved ion exchange resins. The sulfonation of phenol from the standpoint of dihydroxydiphenyl sulfone formation is of considerable industrial interest since the sulfone is an ingredient of several commercial German tanning preparations (376, pages 16, 23, 38). The reactions are as follows: CsH60H

+ HzSOr ---+ HOCBHaSOsH + HzO + CsHsOH * (HOCBH~)ZSOI+ Hz0

HOCe,H4SOaH

Slightly different conditions are used for producing this sulfone depending on the particular tanning agent desired. For synthesis of tanning agent QUE, phenol oil SR1 (11,500 kg.) and 98% sulfuric acid (3700 kg.) are reacted for 1 hour a t 100" C. t o complete the first step, then vacuum distilled for 48 hours at 170' C. t o complete the second step. For preparation of Tanigan Extra A. directions are given as follows: T o phenol (4100 kg. of

VOl. 43, No. 9

melting point over 38" C.) is added a t 65" C. 98% sulfuric acid (1235 kg.). The mixture is then heated 1 hour a t 100' C., vacuum distilled for 50 hours, the temperature being gradually raised t o 170' C. Approximately 2000 liters of water-phenol mixture is recovered as distillate. On the other hand, in producing this sulfone for Tanigan Supra DLN, an excess of phenol is not used (as Tanigan Extra A) to help remove the water, but chlorobenzenes are added for this purpose-water in the distillate being run to waste and the chlorobenzenes being returned t o the reaction vessel. Still another process, using 65% oleum, has been described (180). The oleum is added to the phenol during I/* hour a t 125" t o 130' C. followed by refluxing with chlorobenzene-o-dichlorobenzene mixture for 24 hours a t 150" to 152" C. t o remove water. The yield, based on phenol, is 93.5 to 95.5% of theory. Hinkel and Summers (144) made a study of preparation of the sulfone from phenol (2.5 moles) and 98% acid (1 mole). By raising the temperature quickly to 165" C., holding it for 6 hours, then raising it to 195' t o 200" C. for 6 more hours, an 86% yield of sulfone was obtained, 16% being 2,4'-isomer and the rest being 4,4'-isomer. If the reaction mixture was first held at 25" to 30" C. for 3 days before heating as above, the total yield was 78%, and 24% was the 2,4'-isomer. This is the expected result, since higher temperatures favor para substitution. Monosulfonation of a phenol (40% phenol, 50% cresol, 10% xyleno1)formaldehyde resin with monohydrate acid is described ($76) as a step in producing a tanning agent (Tanigan Extra B). Sulfonation is effected at 70" t o 80" C. for 6 hours in the presence of acetic anhydride. The sulfonation of rn-cresol has been studied (154) toward maximum formation of the 6-isomer as the first step in an improved procedure for producing thymol by subsequent propylation followed by desulfonation. Moderately strong conditions are stipulated t o obtain the 6-isomer, in preference to the 4-isonier--e.g., 3 moles of 9Syo acid per mole of rn-cresol a t 100" to 120' C. Strong conditions in this case are stated to favor sulfonation ortho to the hydroxyl group, while in the case of phenol higher temperatures favor para substitutions. Cresolsulfonic acid (structure not given) was prepared by heat ing cresol with 98% sulfuric acid for 5 hours a t 100" C. (37'6,pag 9). The product was processed further to yield tanning agents. Commercial cresol (Cresol DAB6, 40 t o 50% rn-cresol) was also converted to the sulfone as described above for phenol. Cresel DAB6 (830 kg.) is added to 9870 acid. The cresol is sulfonated for 1 hour (temperature not given) and then distilled under vacuum for 35 hours, the temperature rising to 170" C.; 300 to 400 kg. of cresol are removed with the water (3'76, page 37). The sulfone is used as a raw material for Tanigan Extra S. In connection with a study of the structure and activity of synthetic tanning agents, Ekstrom (90)prepared p-cresolsulfonic acid and condensed it with formaldehyde to the corresponding diphenylmethanedisulfonic acid in 91 % yield. The same disulfonic acid was also made by first condensing p-cresol with formaldehyde, followed by disuifonation. The sulfones of p-cresol and of 2,4-dimethylphenol were prepared by heating the corresponding sulfonic acids, the former sulfone being obtained in 20oJ, yield. Methyl salicylate is sulfonated with gaseous sulfur trioxide without use of a solvent over the temperature range 25" to 111" C. ( 1 3 4 ) , in an improved process for preparation of the higher alkyl esters of sulfosalicylic acid by transesterification of the sulfonic acid of methyl salicylate so obtained with the appropriate higher alcohol, such as Lorol from coconut oil. The final products are light in color and stable. The ethyl and propyl ethers of cardanol (phenol substituted in the meta position with a n unsaturated 15 carbon atom straight chain, obtained from cashew nut shell oil) have been sulfonated by heating 40 t o 60 minutes with equal weights of concentrated sulfuric acid a t 110" C. (137). The products are described as sulfonic acids, but undoubtedly some sulfation of the unsaturated

September 1951

INDUSTRIAL AND ENGINEERING CHEMISTRY

2033

C W R T E S I BHARPLES CONTINENTAL CORP.

Figure 3.

Pilot Plant for Sulfonation of Detergent Alkylates

side chain occurs as well. The silts are useful as detergents and of xylenes (reference 126, 2$5)j and 2,5-dichlorotoluene from a wetting agents. mixture of dichlorotoluenes (reference 116,224). The sulfonation of phenol (also naphthol and anthranol) alThe preparation of 2-chlorotoluene-4-sulfonic acid by the sulkylated with the alkyl ethers of phenols with unsaturated side fonation of toluene followed by chlorination has been described chains (as eugenol and safrole) to produce wetting agents has (370) as operated industrially in Germany. The sulfonation of toluene is carried out as detailed above for the para isomer. been patented (135). The alkylation and sulfonation steps are Additional monohydrate acid (2300 kg.) is then added, together conducted simultaneously. Sulfonation of the condensation product of phenol ( 3 moles) with hexachloroethane (1 mole), with ferric chloride (0.3 kg.), and chlorine is introduced over 45 stated to be l,l,l-trichloro-2,2,2-tris(p-hydrosyphen~~~)ethane, hours a t 50' to 53' C. The desired product is isolated as sodium followed by chlorination, yields an improved mothproofing agent salt in 70 to 7201, yield. This proress would be expected to yield a purer product than sulfonation of o-chlorotoluene. (140). MISCELLANEOUS BENZESEDERIVATIVES.This category inSulfonation of DDT is described (305)using chlorosulfonic acid cludes the amino, rhloro, and nitro derivatives of benzene, toa t 40" to 50" C. for 3 to 4 hours, or 20% oleum a t 80" C. for 5 gether with several miscellaneous derivatives. hours. The sodium salts were used to impregnate fabrics (as Monosulfonation of chlorobenzene with chlorosulfonic acid on wool), the sulfonic group giving good adherence to the fibers with a laboratory scale is described in detail by W. A. Cook and K. H. consequent permanent insect proofing (resistant to repeated washing or dry cleaning). D D T is soluble in the common dry cleaning Cook (68), who state that literature data on this subject is inadequate. The reaction is run a t 10" to 15'' C., using 2 moles each solvents and, therefore, does not confer insectproofing of the permanent type. of the reagents, the acid being added to the chlorobenzene over a Treatment of triphenyl-3-hydroxypropanoic acid with a mix60-minute interval. The crude sulfonic acid is purified via soture of sulfuric acid and oleum leads to simultaneous dehydration, dium salt. ring closure, and sulfonation (193) as follows: 4-Chlorobenzenesulfonic acid, now available in quantity as a by-product of DDT manufactuie, has been converted to a number of new derivatives (sulfones, sulfonamides, sulfonate esters) of CSH, possible insecticidal and fungicidal interest ($16). The sodium sulfonate was first converted to the corresponding sulfonyl chloride or fluoride as key raw material. Sulfonation has been disclosed (242) as a method of selective 0 removal of the meta isomer from a mixture of chlorotoluenes, since this isomer sulfonates more readily than the ortho and para This product, as well as the corresponding 3,3-ditolyl analog, gives isomers. Sulfonation was effected with 9670 acid for 2 hours a t satisfactory dyeing of wool to a n orange color. 150' to 210" F., using from 0.34 to 1.6 pounds of acid per pound of Diphenyl monosulfide has been disulfonated in the para posimixed chlorotoluenes. The sulfonic acid can be steamed for retions by addition of concentrated sulfuric acid (357). covery of the desired purified isomer by hydrolysis, or it can be 4Nitroaniline has been sulfonated with fifteen times its weight fused for conversion to dihydrouytoluenes. Selective sulfonation of 98.70/, sulfuric acid a t 150' C. for 8 hours to yield the monosulhas previously been used for srgregating m-uylene from a mixture

INDUSTRIAL AND ENGINEERING CHEMISTRY

2034

fonic acid ortho t o the amino group. The sulfonic acid is chlorinated in aqueous solution t o yield 2,6-dichloro-4-nitroaniline(by replacement of the sulfonic group) as part of an improved process for producing this material (807). German industrial rocesses for sulfonating several aminosubstituted benzene Arivatives have been published. N-Isobutylanthranilic acid (500 kg.) is dissolved in 98y0 acid (900 kg.) a t 30" to 40" C.; 65y0 oleum (750 kg.) is added a t this temperature, and the batch is then heated for 3 hours. Upon dilution with ice water and cooling, the desired sulfonic acid (sulfonic group para t o amino group) crystallizes and is filtered in 93 to 94% yield (379). pToluidine (40.5 kg.) is added a t 110" C. to a mixture of 96% acid (39 kg.) and water (15 kg.). The mixture is baked for 73 to 76 minutes at 180" C. for 8 to 10 hours. The sulfonic acid can be isolated as sodium salt or as free acid (366). 5-Chloro-2-aminotoluene (320 kg.) is heated a t 180' C. with 75% acid (300 kg.) for 31/2 hours. The mixture is then baked at 250' t o 300' C. for about 6 hours. The final yield is 500 kg. of sulfonic acid (371). Manufacturing details for mono- and disulfonation of 4-aminoazobenzene,.as operated in 1939 by I. G. Farbenindustrie a t Leverkusen, have been published (186). The organic amine (600 kg.) is added to 8 mixture of monohydrate acid (1860 kg.) and 65% oleum (265 kg.) a t 20" to 30' C. The mixture is homogenized by agitation for 5 hours a t 25" C. Then, 65% oleum is added over a 12-hour period a t a temperature determined by whether the mono- or disulfonate is desired, followed by a specific digestion time in each case as shown in Table 11. The monosulfonate is the 4'-isomer, while the disulfonate is the 3,4'-isomer. Total yields of both isomers is 90%.

Table II. Sulfonation of 4 - A m i n o a z o b e n z e n e Temp. $f Addition, C.

Digestion Time a t Same Temp., Hours

0

36

10-12 19-20

24 12

Product Mono Half mono, half di Di

4-Nitrochlorobenzene (158 parts) was sulfonated by dissolving in 20% oleum (600 parts) and heating 6 hours a t 140' C. (307). The resulting sulfonic acid is converted t o the sodium salt, reacted with ammonia under pressure to replace chlorine, and then chlorinated to yield 2,6-dichloro-4-nitroanilincby an improved process. Sulfonation of 4-nitrochlorobenzene with 20% oleum a t temperatures above 120' C. has been shown t o be extremely hazardous (,?%$).Appropriate care should therefore be taken in repeating the experiment as detailed i a the patent. Another hazardous sulfonation is that of 2-nitro-6-chlorotoluene with 20% oleum as operated industrially in Germany (376). During addition of the oleum to the nitro compound, the temperature must not exceed 85" C., or decomposition will occur. The phenylhydrazide of palm oil fatty acids has been acylated with butyryl chloride, and the product obtained (20 parts) sulfonated by suspending in monohydrate acid (20 parts), and treating gradually a t 5' to 10" C. with a mixture of oleum and concentrated sulfuric acid followed by heating 6 hours a t 10' to 20' C. The dried sodium salts are efficient emulsifying and washing agents (116). a$-Diphenylethylamine ( 5 parts), dissolved in 100% sulfuric acid, is sulfonated with 23% oleum (15 parts) (340). 2-BenzylcyclohexyIamine(4 parts), dissolved in 100% sulfuric acid (8 parts), has been sulfonated by addition of 23% oleum (6 parts). The solid sulfonic acid was obtained by drowning the reaction mixture in ice water and filtering (340). 4-Chloro-a,a-diphenylmethyIamine(prepared as detailed, 25 parts) was dissolved in 10% oleum (80 parts) and sulfonated by addition of 23y0 oleum (20 parts). The solid sulfonic acid is isolated by drowning in ice water and filtering (340). The above three sulfonates were condensed with leuco compounds which upon oxidation yielded improved dyestuffs of blue to violet shades.

Vol. 43, No. 9

The quaternary compound from benzyl chloride and dimethylaniline has been disulfonated to yield Leucosol W. The same disulfonate was prepared by reacting a-chloro-4-toluene sulfonic acid with dimethylmetanilic acid (260). A series of 6-anilino-3-azobenzanthrone dye bases has been prepared and monosulfonated on the anilino group (ortho to the amino group) by stirring overnight a t room temperature 1 part of dye with 5 to 6 parts of monohydrated acid. In some cases short heating periods were required. The dyes were precipitated as filterable solids by pouring on ice (4). l#'henoxyanilino-substituted anthrapyrimidine dyes have been mono- and disulfonated using monohydrate acid, 5y0 oleum, or 20% oleum in various examples (386). Sulfonation temperatures ranged from 0' to 50' C. Entering positions of the sulfonic groups were not stated; probably sulfonation occurred on the reactive phenoxy or anilino groups. Polycyclic Compounds. NAPHTHALENE DERIVATIVES.AIthough nothing fundamentally new has been noted on the sulfonation of naphthalene and its derivatives, details have become available of manufacturing processes, as operated recently by the I. G. Farbenindustrie in Germany, which differ in some respects from the same processes as performed on a laboratory scale (104). This is especially noticeable for reaction times and for modes of addition of the reagents, since alternate incremental addition is more frequently practiced in large scale sulfonations. Consequently, several of these processes will be reported in some detail. Manufacture of naphthalene-8-sulfonic acid (as an intermediate for 8-naphthol) by ('a manufacturing process in current use" (in the United States) has been described (100,pages 133-7), together with a flow diagram, equations, over-all yield t o p-naphthol, raw material requirements, four alternative neutralization procedures, and details of the fusion step. The sulfonation is conducted by addition of 66" BB. acid (3000 pounds) to molten naphthalene (2400 pounds), while allowing the temperature to rise gradually t o 160' C. The charge is then held a t 160' to 165' C. for several hours, during which time water and some naphthalene distill off. The reaction mixture (85% beta isomer and 15% alpha) is freed of the alpha isomer by blowing with dry steam a t 160' t o 165' C., thereby hydrolyzing the undesired isomer to naphthalene and sulfuric acid. The German manufacturing procedure for the p-sulfonic acid, as operated a t Hochst in 1945 (173) involved the same general rocedure. Crude na hthalene (1000 kg.) was melted and {eated 2 hours a t 163" with 96% acid (980 kg.). The yield of vacuum-distilled @-naphthol (details of sulfite neutralization and fusion are given) was 4150 kg. from 3 batches, melting point 160" to 180' C.

8.

The preparation of crude naphthalene-&sulfonic acid as intermediate for preparing tanning agents has been described, the conditions varying with respect to the specific product being prepared. In one case (48, page 4),naphthalene and 98% sulfuric acid (2000 kg. each) are heated for 5 hours a t 160' to 165' C. page 43), the same weights of reagents are In a second case (4.2, heated for 1 hour a t the same temperature, while in a third exampage 14), naphthalene (1308 kg.) is reacted with 1 0 0 ~sulo ple (4.2, furic acid (2190 kg.) over 4 hours a t 80' to 90" C., then heated to 110' C. for 11/, hours (see below for possible ratio of isomers). Sulfonation of naphthalene a t 160" to 170" C. is cited in a recent patent (116)for preparing the sulfonic acid as an intermediate for tanning agents. Frohmader, in a patent on the preparation of improved ion exchange resins (Ill), states that heating naphthalene (1 mole) with 98% sulfuric acid (1 to 3 moles) a t between 70" and 90' C. yields a product containing approximately 90% alpha acid and 10% beta acid, whereas a t 110' C. the proportions are approximately 75% alpha acid and 25% beta acid. Process details have been published for the disulfonation of naphthalene, both to the 1,5-isomer and to the mixed 2,6- and 2,7isomers, as operated fairly recently in Germany.

September 1951

I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY

To prcpare the 1,Sisomer (186), naphthalene (2000 kg.) is added to a niisture of 2070 oleum (2760 kg.) and 6570 oleum (3000 kg.) a t not over 35' C. Two further portions of 2070 oleum (720 liters) are then added alternately with two portions of naphthalene (200 kg.) a t the same temperature. Then nine portions of 6570 oleum (275 kg. each) are alternated with nine portions of naphthalene (seven of 200 kg. and two of 100 kg.). A final portion of 65% oleum is then added (525 kg.). The temperature is raised t o 55' C. and held there for 6 hours, the entire procedure to this point requiring 40 t o 42 hours. The desired l,5-isomer is separated either as free acid or as sodium salt in 53 to 547" yield, and in a purity of 88 to 90%. -4second procedure (186) fof ,preparing the 1,5-isomer (containing some 1,6r) involves addition of naphthalene (800 kg.) t o monohydrate acid (1000 kg.), the temperature rising to 70" t o 75" C. The temperature is held 1 hour a t 80" to 85' C., raised over 2 hours to 145' C., and held there 1 hour. The temperature is lowered to 90; C., further monohydrate acid is added (840 kg.), and the batch is cooled to 30" t o 35' C. Further 65% oleum (1390 kg.) is added over a '7-hour p o d The sulfonation is completed by heating to 80" C. a n holding for 1 hour. The sulfonation mixture is nitrated directly. The preparation of 1,5naphthalenedisulfonyl chloride is described later. Two rocedures have been published for preparing the mixed 2,G- an~Z17-isomers. I n one case (186), naphthalene (600 kg.) is added over 20 minutes to 96% acid (3000 kg.), the temperature rising from 125" t o 140' C. during addition. The reaction misture is then held 14 hours at 158' to 162' C., after which it is nitrated directly toward preparation of Freund's acid. The second procedure, yielding the two isomers separately, is as follows (179) as operated at I. G. Farbenindustrie, HCichst. Best quality naphthalene (400 kg.) is added over 20 to 25 minutes to a mixture of monohydrate acid (1200 kg.) and water (4 liters) preheated to, 135' C. The temperature rises to 160' t o 165" C. during addition; it is then taken t o 1'75" C. over hour and is maintained a t 170" t o 175" C. for 5 hours. The temperature is allowed t o sink t o 110' o! 120." C. over 10 to 12 hours. Upon treatment of the sulfonation mixture with brine and sodium sulfate, the disodium salt of the 2,6-isomer (21.6% yield) separates a t 90" C. and is removed by filtration. The 2,7-isomer (42.27, yield) separates from the filtrate upon cooling t o 20" C. blanufacturing details for two naphthalenetrisulfonic acids have been published, as practiced recently by the I. G. Farbenindustrie in Germany. For the 1,3,5-isomer ( 1 8 6 ) , naphthalene (900 kg.) is added a t 30' to 35' C. t o monohydrate acid (1575 kg.), simultaiLeously with 657, oleum (2880 kg.) over a 32-hour period. T h e mixture is heated to 50" C. and held for 1 hour, then 1 hour at 70' C., and finally 7 hours a t 90' C. Some of the 1,3,6-isomer is also formed. To produce the 1,3,6-isomer (for Koch acid) (186), naphthalene (1000 kg.) is added to monohydrate acid (1300 kg.) a t 20' C. The batch is heated to 80" t o 85" C. and held for 1 hour, then heated t o 145" C. and held 1 hour. After cooling to 85" C., further monohydfate (965 kg.) is added, then at 40" C. 657, oleum (2560 kg.) IS added over 8 to 9 hours. T h e batch is heated to 145' C., held 2l/2 hours, cooled t o 50" to 60' C., and 65Ye oleum is added (300 kg.). Reaction is finally completed by heating for 3 hours at 150' to 155' C. Preparation of a reaction mixture of unsIated composition containing naphthalene mono-, di-, and trisulfonic acids by treatment of naphthalene (1 part) with 207, oleum (2 parts) at 160' C. for 2 hours has been disclosed (243) for use in preparing nickel salts used for bright nickel plating. Manufacturing data have been made available ( 1 8 6 ) for preparing the di- and trisulfonic acids of 01- and p-naphthylamine, as conducted by I. G. Farbenindustrie a t Leverkusen in 1945. For l-aminonaphthalene-2,5,7-trisulfonicacid, l-aminonaphthalene-5-sulfonic acid (290 kg. of 100% equivalent) is added at 20" C. t o a mixture of monohydrate acid (900 kg.) and 20% oleum (1800 kg.). Additional 20?, oleum (840 kg.) is then added, the temperature rising to 40" C. The batch is cooled t o 20" C., more starting amino compound is added (290 kg.), then 6570 oleum (840 kg.). The batch is heated over 4 hours t o 120" C. t o complete conversion to the trisulfonate. The trisulfonate is converted t o l-aminonaphthelen~5,7-disulfonicacid by pouring into water (7000 liters) and heating 10 hours a t 130' C., adding make-up water as needed t o a final volume of 3000 liters. The disulfonic acid crystallizes on cooling in 66% yield. I n a similar type of operation, 2-aminonaphthalene-1-sdfonic acid is trisulfonated to the 2-aminonaphthalene-l,5,7-trisulfonie acid, then hydrolyzed t o the l-amino-5,7-disulfonic acid. The starting amino compound (900 kg.) is added with cooling at 30" to 40' C. t o 20yc oleum (2700 liters). Then, 657, oleum (650 kg.) is added at the same temperature, followed by additional organic compound (900 kg.) and further 65% oleum (650 kg.).

2035

The batch is stirred 2 hours, then heated over 5 hours to 100" C., where it is held for 12 hours t o obtain the trisulfonic acid. To effect hydrolysis, water is added (l0,OOO liters) and the batch is heated t o 105' C., where it is held for 3 hours. The product separates on cooling t o 20" C. An 80% yield of the desired disulfonate is obtained in the form of sodium salt. For the disulfonation of p-naphthylamine, the amine (300 kg. ) is added to 20% oleum (800 liters); a similar quantity of acid is added, then a similar amount of amine. Seven increments each of 657, oleum (550 kg.) and amine (three of 200 kg. and four of 100 kg.) are added alternately, followed by a final addition of 657, oleum (750 kg.). The addition requires 24 hours at a temerature of 30" t o 35' C. The batch is then heated to 70' C., geld for 1 hour, then heated t o 95" C., and held for 15 hours to complete sulfonation. 2-Amino-6,8-disulfonic acid (amino-Gacid) separates as a solid in 48.57, yield. The filtrate contains 2-aminonaphthalene-l15,7-trisulfonicacid, which is hydrolyzed t o 2-aminonaphthalene-5,7-disulfonicacid (amino-I-acid) in 30.5% over-all yield. According t o a statement in a recent paper on the caustic fusion of 6-methyl-2-sodium naphthalenesulfonate (311 ), the sulfonation of 2-methylnaphthalene has been studied thoroughly. No details are presented, but references are given to three unpublished theses (dated 1948), and to an earlier publication by one of the authors (dated 1943) cited in a previous sulfonation review (reference 269, 223). Sulfonation of 2-methylnaphthalene in the 6 position may be accomplished by treating the hydrocarbon (400 parts) with 95% acid (395 parts) or with monohydrate acid (377 parts) a t about 160" t o 170' C. for 3 hours (55). The sulfonic acid was then converted t o the corresponding 2-methyl-6-naphthol by caustic fusion. The sulfonation of benzylnaphthalene has been described (376, page 11). Oleum (724 kg. of 20%) is added to benzylnaphthalene (prepared from 490 kg. naphthalene and 447 kg. benzyl chloride) at 55' t o 60' C. in a n iron kettle; the reaction is completed by heating to 116" C. A second description (376, page 36) is ident i e d , except that 830 kg. of 20% are used. The products are intermediates for preparing tanning agents. 1-Cyclopentylnaphthalene (10 grams) has been sulfonated at -4' C. in carbon tetrachloride solution (25 ml.) with chlorosulfonic acid (6.42 grams) covered with carbon tetrachloride (5 ml.). The 4-sulfonate was isolated as potassium salt (20). I n the sulfonation of poly-2-vinyl-naphthalene (997), the number of sulfonic acid groups introduced into each naphthalene unit was 0.4 or 0.7 when treated with fuming acid in the solid state or in nitrobenzene solution, respectively, and 0.9 when treated with chlorosulfonic acid in carbon tetrachloride. The sulfonation of a mixture of naphthalene with spermaceti and of a mixture of naphthalene (plus other aromatic hydrocarbons) and sunflower oil is discussed under the heading F a t t y Oils. One case each of the sulfonation of a long-chain alkylated naphthalene and Tetralin is cited under detergent alkylates. p-Naphthol has been sulfonated for the preparation of tanning agents. In one case (376, page 38), @-naphthol (1400 kg.) was sulfonated 1 hour at 120" C. with 98% sulfuric acid (I580 kg.). I n a second description (376, page 44) p-naphthol (650 kg.) was added t o 98% sulfuric acid (540 kg.), the temperature being slowly raised to 115" C. over a period of 2 hours. Mixtures of p-naphthol and naphthalene have also been sulfonated for preparation of tanning agents. Thus (376, page 41) p-naphthol (35 kg. in flake form) and naphthalene (312 kg. crude) are mixed in a tile-lined sulfonation pan and 100% sulfuric acid (347 kg.) is added over 3/( hour a t 80" t o 85" C. The reaction mixture is then heated t o 125" C., after which it is stirred 2 hours a t 120" C. In a second case (376, page 42) p-naphthol (75 kg.) and naphthalene (675 kg.) are melted in an iron sulfonator and 98% sulfuric acid (750 kg.) is added over 5 to 6 hours a t 80' to 90" C. The reaction is completed a t 100' C. The preparation and properties of the barium salts of 1,5-dinitro-2-naphthol-7-sulfonic acid have been described (380).

2036

INDUSTRIAL AND ENGINEERING CHEMISTRY

Thc German industrial rocess for sulfonating 2-hydroxy-3naphthoic acid has been &tailed (867), involving incremental addition of the organic acid in 200-kg. portions (total 1200 kg.), altcrnatcly with monohydrate acid (600-kg. portions, total 3600 kg.). Initially, the reactor is charged with a portion of monohydrate plus water (90 kg.); no more water is added with further portions of acids. The temperature is not allowed t o exceed 18' C. during addition. The batch is finally stirred 40 t o 48 hours at 30' C. The.product, upon drowning in aqueous potassium chloride, is obtained as potassium salt, 7570 being the 8-sulfonic acid, and 25y0 being the 6isomer.

Vol. 43, No, 9

enol acetates (395). Data given in examples are presented in Table 111. These materials probably contain fused benzene rings. Ion exchange resins have been prepared by steaming the acid sludgc resulting from the treatment of coal carbonization light oil with 20% oleum or 66' BB. acid for refining purposes (SI). Working capacities of the resins are usually about 7500 t o 9000 grams per cubic foot. SULFITE REACTIONS

For commercial sulfonation of 4-amino-l,8-dicarboxy-naphthaIene (874),the base (200 kg.) is added a t 20" C. over 2 hours into a mixture of monohydrate acid (200 kg.) and 20% oleum (860 kg.). The batch is then heated to 60" C. and held a t that temperature 3 / r hour. The sulfonic acid is obtained by diluting with ice water and filtering. Filtering requires 2 days. ANTHRACENEDERIVATIVES. The studies of Kozlov on anthraquinone sulfonation have been continued in a paper on hydrolysis of the monosulfonic acids (813). Contrary to the literature, no mercury is required t o obtain good yields of anthraquinone by hydrolysis of the 1-isomer, although the reaction is greatly accelerated by mercury salts. Thus, yields of 64 to 90% of anthraquinone were obtained by heating anthraquinonesulfonic acid (or its sodium salt) with 85y0 sulfuric acid in the 190' to 280' range in a n open vessel or under pressure; a good yield was also obtained with 5y0acid by hydrolysis under pressure a t 230' C. Certain conditions (such as heating with water a t 180' to 300' C.) favored oxidation yielding I-hydroxyanthraquinone plus sulfur dioxide. I n the case of the 2-isomer, only a n 8% yield of quinone could be obtained with or without mercury. Hydrolysis of the 1,2-disulfonic acid in the presence of mercury salts led to formation of the 2-acid, only one sulfonic group being removed. The preparation of 2-phenylanthraquinonesulfonic acid has been disclosed (364) as a step in the preparation of 2-phenylanthraquinone by hydrolysis. This reaction, a case of simultaneous ring closure and sulfonation, is carried out by heating 2(phenylbenzoy1)benzoic acid ( 1 part) with 95% sulfuric acid (5 parts) a t 125" C. for 2 hours. The desired sulfonic acid is precipitated by dilution with water (5 parts). Although the position of the sulfonic group is not specified in the patent, i t is probably located on the phenyl group. A recent Italian patent ( 1 9 ) discloses the preparation of dihydroxychloroanthraquinonemonosulfonic acids without the use of aluminum chloride. Phthalic anhydride (276 parts) is monosulfonated with 30% oleum (900 parts) by heating from 130' to 210' C. 3,4-Dichlorophenol (97.6 parts) and boric acid (58.8 parts) are added and the reaction is concluded by heating from 160' to 210' C . The product obtained is claimed to be:

This is an adaptation of an old process (104) for making quinisarin by reacting 4-chlorophenol with phthalic anhydride in the presence of boric acid and concentrated sulfuric acid. MISCELLANEOUS.The sulfonation of 9,9'-spirobifluorene has been studied (389). With concentrated sulfuric acid, sulfonation occurred only above 100" C., yielding the 2,2'-disulfonic acid. The same product was obtained with chlorosulfonic acid in refluxing chloroform. The concurrent sulfonation and oxidation of charcoal, coal, coke, graphite, and carbonized wood pulp or sawdust has been described for preparation of catalysts promoting condensation of ketene with various ketonic compounds t o yield

The German operating procedure for preparing potassium osulfobenzoate, as operated by I. G. Farbenindustrie at Leverkusen (185), has been published. o-Chlorobenzoic acid is heated with aqueous sodium sulfite in the presence of copper sulfate catalyst for 6 hours at 145' to 150' C. at 4 t o 5 atmospheres absolute pressure. The potassium salt is prepared by treatment of the sodium salt so formed with aqueous potassium chloride; the yield is 84%. It is of interest t o compare this German process with a similar one disclosed in a Swiss patent previously reviewed (reference 273, 8.83). The heating time mentioned in the patent is 10 hours at 170' t o 175' using the same catalyst. Preparation of a water-soluble monosodium bisulfite derivative of 2-methyl-l,4-naphthoquinonehas been disclosed in a Swiss patent (5.3). Chemical composition of the product, which has vitamin K activity, is not disclosed. Other investigators have previously prepared this product and proposed a chemical structure for it (references 16 and 216, 884). Bogdanov and coworkers have continued their, studies of sulfonation with sulfites. I n one paper, the sulfonation of l-naphthylamine and 1-naphthol with sodium bisulfite-mercury oxide was studied (34). Refluxing the amine (30 grams) with Nar[Hg(SO&] (21.3 grams) in water (100 ml.) for 2'/2 hours yielded 1.72y0 N-sulfonic acid and 16.8% carbon sulfonic acids which consisted of 68% of I-aminonaphthalene-4-sulfonicacid and 310/, of the 2-isomer. I n the case of I-naphthol, under similar conditions, the maximum yield obtainable amounted t o 3% of sulfonic acids comprising a mixture of the 2- and 4-isomers; a similar yield was obtained using a mixture of sodium sulfite and manganese dioxide. I n a second paper, Bogdanov and Migacheva (33) studied the use of several possible oxidizing agents for introducing additional sulfonic groups into various 2-naphtholsulfonic acids with bisulfite. 2-Naphtholsulfonic acids studied included the 4-, 6-, and 7-isomers as well as the 3,6-disulfonic acid. Effective oxidizing agents, with per cent yield of the new sulfonic acids, are as follows: potassium permanganate (14.5 t o 28), silver oxide (19), ferric chloride (23 t o 39), copper sulfate (24 to 50); 1,a-naphthoquinone-4-sulfonic acid was also a n effective oxidizing agent. The following oxidizing agents were ineffective in promoting sulfonation: iodine, hydrogen peroxide, potassium persulfate, and silver nitrate. I n a discussion of the mechanism of this reaction, the authors postulate a basic similarity t o ordinary sulfonatioo with sulfur trioxide derivatives, the transformation of sulfite ione t o either sulfate or SZOBprobably proceeding by met8alion complexes. A recent Swiss patent (56) discloses the preparation of l-amino2-hydroxy-6-methoxynaphthalene-4-sulfonicacid by treatment of the 1-nitroso analog with sodium bisulfite, followed by hydrolysis with mineral acid. The sulfonic acid so obtained is used as a dye intermediate. The equation for this reaction is as follows:

NO 1

NHz I

Scalera (300)has prepared 1-sulfo-2-carboxyanthraquinoiie in excellent yield and high purity by refluxing a mixture of l-nitro-2-

INDUSTRIAL AND ENGINEERING CHEMISTRY

September 1951

2037

carboxyanthraquinone (29.7 parts), water (400 parts), sodium carbonate (5.6 parts), and sodium sulfite (37.8 parts) for 10 hours. On cooling and acidifying, the sodium salt of the desired sulfonic acid is obtained in good yield. The equation is:

These may be polymeric in nature, as when formaldehyde is reacted with naphthalenesulfonic acids. Polymeiic sulfonic acids of analogous structures prepared by other methods are discussed above under Sulfomethylation and under Polystyrene ; direct sulfonation of polyvinylnaphthalene is cited above under so2 Naphthalene Compounds. Condensation may also proceed through other functional groups on the aromatic sulfonic acid, as hydroxyl, amino, or halogen. A condensate having tanning properties has been prepared (115) by reaction of naphthalene sulfonated a t 160" t o 170" C. (largely the beta isomer) with aqueous formaldehyde (30%) at II 0 95" to 105" C. in the ratio of 2 moles of sulfonic acid to 1 mole of formaldehyde. The condensate is further reacted with a quaterThis general type of replacement reaction is well known; sodium nary compound, phenyldimethylammonium methyl sulfate, to nitrite is also usually formed. yield a textile assistant. The reaction of bromocyclohexylamino-substituted anthraA liquid tanning agent has been prepared from cresolsulfonic quinones with aqueous sodium sulfite under pressure t o replace acid, urea, and formaldehyde (114) and reacted with a quaternary the bromine atom with the sulfonate group has been disclosed in compound t o yield a textile assistant. a recent patent on production of improved blue dyes (6). A soluble synthetic tanning agent has been prepared by Bolgar I n an extended study of the mechanism of the Bucherer reac(36) by reacting p-naphthalenesulfonic acid (256 grams) and tion for the conversion of naphtholsulfonic acids t o naGhthylwater (20 grams) with a condensate (100 grams) prepared at aminesulfonic acids and vice versa Kith bisulfites, Cowdrey has in70" C. from aqueous formaldehyde (400/,, 360 grams), water (100 dicated as the major reaction product ( 7 0 )of sodium naphthionate grams), ammonium sulfate (34 grams), and urea (60 grams), and sodium bisulfite an aminosulfonate of structure shown below: followed by neutralization. Polymeric products are formed containing the basic unit (-NHCONHCH2CloH&OpH). Nilsson (244) has disclosed a n improved process for preparing ion exchange resins from p-naphthalenesulfonic acid and formaldehyde. The reaction is conducted in stages. In an example, one fifth of the formaldehyde is added to the acid a t 75" C.; SO3the remainder of the aldehyde is then added and the temperature The sodium naphthol sulfonatebisulfite addition compound i~ lowered t o 65" C., and in the final stage the temperature is raised to 100" C. t o achieve the desired consistency. postulated as a hydroxysulfonate as shown: I n a recent patent ( I l l ) , Frohmader indicates t h a t ion eyOH SO3change resins prepared from a predominantly a-naphthslenesul\/ fonic acid (at least 75%) by condensation with formaldehyde are superior to those prepared by previous practice from the beta isomer. The new products are harder, less water-soluble, impart less color, and have better exchange capacity. I n a n example, the I a-naphthalenesulfonic acid (prepared by direct sulfonation a t not SO,-

y

8 '' \/

Table 111. Raw Material 20-40 mesh bituminous coal 20-40 mesh bituminous coal 20-40 mesh bituminous coal Finely ground resistor carbon Finely divided natural graphite Fine petroleum coke 40 mesh by-product coke Activated charcoal (coconut shell) 40 mesh bone charcoal 4-20 mesh hardwood sawdust Sulfite process wood pulp

Parts 100 100 100 100 100 100 loo 100 100 150 100

Sulfonation of Coke, Charcoal, Graphite, and Sawdust Designation1 2

R

..

F

c' .. ..

N

Temp., Sulfonating Agent 96% acid Chlorosulfonio 20% oleum 20% oleum 20% oleum 20% oleum 20% oleum 20% oleum 20% oleum 96% acid. 20% oleum 96% acid; 20% oleum

Parts, MI. 400 400 400 200

200 400 400 300 400 2 0 0 ; 400 200; 400

c.

Hr.

80 80 80 80-90 80-90 80 80-90 80-90 80-90 80-90 80-90

21/z

6.87%

21/?

9.22% 3.71%

21/z

Sulfurb

41/2

21/s 21/2 21/2

21/z

2 21/2

21/?

2,22%

2.19 meq. O.l$'meq. 1.10% 2.81% 1.67 meq.

Kote c c

d

...

... .. . ... . .. . e. .

As used in original reference (996). Sulfur is expressed as per cent, or a s milliequivalents per gram. See original r e f e r a c e s for carboxylic acid analytical data. Oxidation occurred in r u n 1, b u t not in run 2, showing the difference in sulfonating agents. d Secondary treatment with nitric acid used in this run. e Preliminary carbonization done with 96% acid.

a

b

C

An analogy is drawn to the reaction of formaldehyde-bisulfite (hydroxymethanesulfonic acid) with ammonia to yield the iminomethane sulfonate. Compound A is regularly isolated on a large industrial scale in the conversion of napthionic acid to l-naphthol4-sulfonic acid, but its chemical structure has not previously been studied. Cowdrey's conclusions have bren criticized (363). CONDENSATION REACTIONS

This category includes the reaction of aromatic sulfonic acids with other organic compounds to produce new sulfonic acids.

above 110" C., preferably between 70" and SO' C.) is added t o aqueous formaldehyde (1.0 to 2.5 moles per mole of naphthalene) a t 65" t o 80' C. Best results are obtained in the subsequent baking operation if the residual sulfuric acid is not entirely removed in washing the crude resinous reaction product. A condensation method for preparing acetoacetanilide sulfonic acids is disclosed in a 1944 German patent application assigned to Zeiss-Ikon (262). A beta keto ester (several examples are cited using ethyl acetoacetoacetate) is heated in pyridine solution with an aromatic aminosulfonic acid (sulfanilic acid and related compounds), ethyl alcohol being formed during condensation. Ex-

2038

INDUSTRIAL A N D ENGINEERING CHEMISTRY

cellent yields of the desired product are obtained; these sulfonic acids are not accessible by direct sulfonation. p-Methoxyphenylphenylcarbinol formed a polymeric sulfonic acid on standing a t room temperature in concentrated sulfuric acid solution for 2 weeks (27). It was converted t o the corresponding sulfonamide by reaction with phosphorus pentachloride followed by ammonia.

Table Method Or snio syntheses Sojium chloride Sodium chloride plus solvent

Another report of work by I. G. Farbenindustrie ( 1 6 1 )contains directions and description of apparatus for preparation of benzenesuifonyl chloride from benzene and chlorosulfonic acid, with a yield of 70.4%. Preparation of the sulfonyl chloride of octylbenezne (from noctanol and benzene in the presence of boron trifluoride-phosphorus pentoxide) has been described in a recent patent (194).

IV. Benrenesulfonyl Chloride Yield Data

Benzene Moles Grams 2 156 2 156 2

Vol. 43, No. 9

156

Sodium Chloride,

Acid Moles

Grams

10.7

6

Grams 700 1250

6

700

120

The preparation of ether sulfonic acids by condensation of a phenolic sulfonic acid with a chloromethyl compound has been disclosed (318). In examples, ar-2-chloromethyltetrahydronaphthalene is condensed with 2-hydroxynaphthalene-6-sulfonic acid, 2,4-dihydroxynaphthalene-6-sulfonicacid or p-phenylsulfonic acid; 2-chloromethylcymeneis condensed with 2-hydroxynaphthalene-6-sulfonic acid, 1-hydroxynaphthalene-5-sulfonic acid, or 2,8-dihydroxynaphthalene-6-sulfonic acid. The products have surface activity and are used as textile assistants. Cyclohexylamine-substituted anthraquinone sulfonate dyes have been prepared by reacting the corresponding bromoanthraquinone sulfonate salt with various aminocyclohexanes in the presence of aqueous caustic soda and copper catalyst (6). In an example, aminocyclohexane is reacted with the sodium salt of l-amino-4-bromo-anthraq~inone-2,8-disulfonic acid. In one case cited, a dibromoanthraquinone is first reacted with an aminocyclohexane to replace one bromine atom, followed by reaction with sodium sulfite to replace the second by a sulfonic group. Sulfonated anthraquinone dyestuffs have been prepared (340) by reacting leuco hydroxyanthraquinones (leuco quinizarin is cited in several examples) with aromatic sulfonic acids containing side-chain aliphatic amino groups, followed by oxidation. Preparative details for the four sulfonic acids used (from or,,% diphenylethylamine, 2-benzylcyclohexylamine, and 4-chloroa,a-diphenylmethylamine,a-phenyl-yaminobutane) are given under Miscellaneous Benzene Derivatives. The chemistry of this reaction is not discussed. SULFONYL CHLORIDES AND FLUORIDES

This category includes all preparations noted of aromatic sulfonyl chlorides and fluorides, whether mono- or polycyclic. I n all cases but one the procedure involves direct treatment of the unsubstituted organic compound (or its sulfonic acid) with excess chlorosulfonic or fluosulfonic acid. Three aromatic sulfonyl fluoride8 (3-nitrobenzene-, 4-chlorobenzene-, and benzene-), have been offered as new products of possible commercial interest (IO),and a bulletin describing them has been issued (267). The preparation of benzenesulfonyl chloride has been made the subject of an interesting study of yields by German investigators (302). It was found that the yield (121, pages 85-86) (75 to 77% of theory) could be raised to 90% by the addition of sodium chloride. The reaction is driven to substantial completion by removal of the sulfuric acid formed as sodium acid sulfate; otherwise this acid tends t o reverse the reaction and lower yields are obtained. Further improvement was obtained (in terms of lowered chlorosulfonic acid requirements) by combined use of the sodium chloride with an organic solvent such as carbon tetrachloride, which is present during the reaction (rather than being added to extract the sulfonyl chloride after drowning the reaction mixture on ice). Table IV summarizes the data.

None 120

Benzenesulfonyl Chloride Grams % 272 75-77 318 90 318

90

Chlorosulfonic acid (9 moles) is added over 1 hour a t 13" to 22" C. to the hydrocarbon (4.04 moles). After drowning in ice water, drying, and purifying with clay, a 71.6y0 yield was obtained. Similar results were noted in a larger scale run. Best results are usually obtained by addition of the hydrocarbon to the chlorosulfonic acid, rather than the opposite procedure as disclosed in the patent. p-Cymene (67 grams) was chlorosulfonated by dropwise addition over 90 minutes to chlorosulfonic acid (180 ml.) a t 0" to 5" C. (47). The yield of 2-methyl-5-isopropylbenzenesulfonylchloride (75 grams) is somewhat lower than reported previously by Huntress and Autenrieth (156). p-Chlorobenzenesulfonyl chloride has been prepared (216) in 89y0 distilled yield by suspending crude dry sodium p-chlorobenzene sulfonate (335 grams) in chloroform (700 ml.) and adding chlorosulfonic acid (370 grams) over a period of 15 minutes with stirring and cooling such that the temperature remained below 60' C. The slurry was then stirred and heated a t 55" to 60" C. for 6 hours. The reaction mixture was poured into ice water, washed, dried, and distilled. The corresponding sulfonyl fluoride was made similarly, carbon tetrachloride being used as solvent. rn-Dichlorobenzene (150 kg.) is added a t 0" to 10" C. t o chlorosulfonic acid (750 kg.) over a 2-hour period to yield 89.2% of the sulfonyl chloride. This process has been operated by I. G. Farbenindustrie a t Hochst (166). The sulfonyl chlorides of 2,4-dichlorotoluene, 1,2,3-trichlorobenzene, and chloro-p-xylene were manufactured a t Mainkur (160)by addition of the organic compound to four weights of chlorosulfonic acid a t 15" to 30" C., followed by 2-hour heating a t 50" to 70" C. Yields were, respectively, 85, 85, and 93% of theory. To prepare p-chlorobenzenesulfonyl fluoride (217 ) ,fluosulfonic arid (200 grams) was added dropwise to chlorobenzene (57 grams) over a period of 3 hours ttt 48" to 50" C.; i t was then stirred and heated for 3 additional hours. After drowning, working, drying, and distilling, a yield of 74% was obtained. It is of interest to compare the above conditions used for formation of sulfonyl halides with those reported for monosulfonation of chlorobenzene with chlorosulfonic acid. A lower temperature and it lower ratio of chlorosulfonic acid is used for sulfonation. p-Nitrobenzenesulfonyl chloride is best prepared from the crude disulfide (obtained by reacting p-nitrochlorobenzene with sodium sulfide in methanol), even though it contains 7 to 13% of the monosulfide (393). Separation of the mono- and disulfides is difficult, entailing large losses. Conversion of the disulfide is accomplished by chlorination in acetic acid. An improved procedure for the preparation of 4-chIoro-3nitrobenzeneaulfonyl chloride has been patented (308)involving treatment of o-chloronitrobenzene with chlorosulfonic acid. In an example, o-chloronitrobenzene (1.25 moles) is added to chloro-

September 1951

INDUSTRIAL AND ENGINEERING CHEMISTRY

sulfonic acid (5 moles). The mixture is heated 1 hour each a t loo", 110", and 120' C., and the reartion is completed by holding 3 hours at 130' C. An 88% yield was obtained upon working up the reaction mixture. This process yields a purer product than the previously used method involving the action of phosphorus pentachloride on the sulfonic acid. The German manufacturing process for this product, as operated a t Leverltusen (167),involved heating o-nitrochlorobenzene with 6.85 moles of chlorosulfonic acid a t 100" to 105" C. for 5 hours t o give an 82 to 84% yield. The isomeric 4-chloro-1-nitrobenzene-3-sulfonyl chloride was manufactured ( 1 6 7 )by adding dried ground 4-chloronitrobenzene%-sodium sulfonate t o chlorosulfonic acid (ratio 1 mole to 9.4 moles) a t room temperature, followed by stirring for 1hour, slowly heating to 98" C., and holding a t this temperature for 2 hours. The reaction mixture was drowned on ice and filtered. An 80% yield was obtained. Salicylic acid was converted to the sulfonyl chloride at Leverkusen (166) by treatment with chlorosulfonic acid (ratio 1 mole to 8.2 moles) a t 40" t o 45" C. The reaction mixture was drowned on ice t o give a 76 t o 87y0yield of l-hydroxybenzene-2-carboxy-4sulfonyl chloride. An extensive process study has been made of the chlorosulfonation of three acyl anilides (acetanilide, phenylurethane, and symdiphenylurea) (320, 561 ), involving a time-temperature-yield study and also considering the effect of sulfuric acid present as an impurity in the chlorosulfonic acid used. The effect of the acid was found t o be negligible as long ae the chlorosulfonic-to-sulfuric ratio was kept constant, regardless of variation in the quantity of anilide being sulfonated. (Apparently the commercial chlorosulfonic acid available to these investigators assayed only 92%; the American product assays 98..5p/, minimum.) Study of the mechanism of reaction a t 50", 60". 7 0 ° , and 90" C. indicated the expected results-namely, primary sulfonation followed by conversion of the sulfonic acid to the sulfonyl chloride, with both steps accelerated by rise in temperature. Acidolysis of the acyl group was an important interfering side reaction which was also accelerated by elevated temperatures, acetanilide being, in this respect, the least sensitive of the three compounds studied. Data were presented showing that to avoid extensive yield loss by the acidolysis the reaction must be run either a t low temperatures or if at elevated temperatures (as in possible continuous operation) with accurate control of reaction time. Phenylurea (40 grams) was chlorosulfonated (221) by addition t o chlorosulfonic acid (80 ml.) at below 10' C. over 40 t o 50 minutes, followed by heating 1 1 / 2 houLs a t 40" to 50" C. A 41.8% yield of N-carbamylsulfanilyl chloride was obtained as a 64y0 paste. According to it recent Japanese patent (SIO),N-phenyl phthalimide (22.3 grams, prepared as detailed from aniline and phthalic anhydride) is chlorosulfonated on the benzene ring para to the amino group by heating with chlorosulfonic acid (43 ml.) a t 60" C. for 2 hours. A yield of 16 grams is obtained. As a step in the synthesis of 8-bisthio compounds and p-disulfones, N-benzylsuccinimide (14 grams) was added in portions t o chlorosulfonic acid (140 ml.) with stirring a t below SO' C. The reaction mixture was then heated to 60" C. for ' / a hour and then poured on ice to yield the solid sulfonyl chloride (29). N Benzylbenzamide (100 grams) was added gradually to chIorosulfonic acid (300 ml.) a t 15" C. n i t h stirring. The reaction mixture was heated at 45" C. for 1 hour to complete the reaction, and was worked up by drowning on ice (29). 2-Benzamidodiphenyl (21.2 grams j was added in portions a t loo C. t o chlorosulfonic acid (42.4 grams). The mivture was heated at 60" C. for 2 hours, cooled, and poured on ice to precipitate 2-benzamido-4-chlorosulfonyldiphenylas a sticky product; treatment with chloroform and light petroleum gave 12.2 grams of needles (234). Aceto-o-anisidine (425 Irg. ) was converted to the sulfonyl

2039

chloride (para t o the methoxyl group) a t Leverkusen with chlorosulfonic acid (1800 kg.) at 35" to 40" C., followed by drowning in ice water, filtering, and washing the solid product (368). Diphenyl was dichlorosulfonated in the two para positions as the first step in an improved process for preparing the corresponding disulfonyl azide (263). In an example, diphenyl (256 parts) was mixed with chlorosulfonic acid (1150 parts) and allowed to stand 3 t o 4 hours a t 20" to 25' C. The reaction misture was poured into water to precipitate the desired product. A temperature-yield study of the conversion of 1,5-naphthalenedisulfonic acid (as dry sodium salt) to the corresponding disulfonyl chloride has been made (329) oveI the range 16" to 114' C., using 10 moles of chlorosulfonic arid to 1% organic compound and a reaction time of 2 hours. A 93% yield of almo3t pure product was obtained a t 98" C. As part of the same investigation, a temperature-yield study was made of the formation of the 1,3,5-trisulfonyl chloride from the same reactants used in the same ratio (Table V )

Table V. Preparation of 1,3,5-Naphthalenetrisulfonyl Temp., O C. 10 65 65 100 Q

Hours to Reach Equilibrium 200-500 14 6-8

2

Chloride

% Yield 89-91

...

1000 84

Excess chlorosulfonic acid used.

Sodium 1-chloro-2-naphthalenesulfonate has been converted t o t>hecorresponding sulfonyl chloride by treatment with phosphorus pentachloride a t room temperature (34). 'The same investigators prepared t.he sulfonyl chloride of I.-naphthylamine-4-sulfonic acid from the sodium salt. Details have been reported (167) for reacting 2-hydrosy-lcarboxynaphthalene with chlorosulfonic acid (ratio 1 mole t o 6.6 moles) a t 30" to 35" C. to yield 82 to 84% of the sulfonyl chloride. This process was operated on a manufacturing scale a t Leverkusen by the I. G. Farbenindustrie.

HETEROCYCLIC C O M P O U N D S FURAN AND THIOPHENE DERIVATIVES

Terent'ev and coworkers have continued their study of direct sulfonation of heterocyclic compounds. [For summary of previous work see ( 2 2 4 ) . ] I n a study (346) of suitable agents for sulfonating furan and sylvan (a-methylfuran), the sulfonating agents tested with results obtained are as follows: sulfuric acid (with or without various solvents), tars; sulfuric acid plus cquimolar pyridine or dimethyl-aniline, no reaction even a t 120" C.; sulfur trioxide (with or without acetic. anhydride j, tars plus traces of sulfonic acids; sulfur trioxide-trimethylamine comples, 15y0 furansulfonic acid in 20 hours a t 100' C.; sulfur trioxidedioxane complex, tars plus sulfur-containing acids from ring opening of furan and dioxane. The pyridine-sulfur trioxide complex (and the picoline complex) works well only when equimolar quantities of reagents are used (226); excess pyridine hinders the reaction. 2-Acetylfuran was sulfonated to yield the 5-sulfonic acid in 82.5 % yield (347) using pyridine-sulfur trioxide at 140" C. in 10 hours with ethylene dichloride as solvent; attempted use of sulfuric acid or sulfur trioxide in ethylene dichloride solvent gave only tars. Sulfonation of furfural resins yields improved ion exchange resins, according to a recent patent (366). Furfural (6 moles) is resinified with concentrated hydrochloric acid (3 moles), and the solid resin so obtained (73 parts) i3 sulfonated in ethylene dichloride suspension (500 parts) with chlorosulfonic acid (146 parts) a t 20" C. over an 18-hour period. Other examples disclose sulfonation with 25% oleum in varying proportions, using

2040

Vol. 43, No. 9

INDUSTRIAL AND ENGINEERING CHEMISTRY

the same solvent techniquc, of the resin prepared with sulfuric acid. Noting t h a t thiophene could not be directly sulfonated with sulfuric acid as indicated in the literature, Halbedel and Heath (130) found fluosulfonic acid to be a satisfactory sulfonating agent, the sulfonyl fluoride comprising the major reaction product together with lesser amounts of the sulfonic acid. I n an example, thiophene (84 grams) was mixed with fluosulfonic acid over 2 hours, and the mixture was agitated for 2 hours additional at between 5' and 10" C. The reaction mixture was then mixed with water (2000 grams) and barium hydroxide crystals (I150 grams), followed by heating for 2 hours at 90" C. Insoluble barium salts (fluoride, sulfate, fluosulionatc) were removed by filtration, yielding a water solution of barium thiophene sulfonate, which was converted to the nickel salt by addition of nickel ruifate; yield 44y0. The position of the entering sulfonic group was not stated: it was probably in the 2 position. As previously reviewed (SW4),thiophene has been recently sulfonated in good yield using the pyridine-sulfur trioxide complex. 2-Acetamidothiophene (8 grams) was dichlorosulfonated (119) by addition t o chlorosulfonic acid (52 grams) over 25 minutes at 25" C.; the yield was 31%, the positions of the chlorosulfonyl groups being assumed t o be 2 and 4 (acetamido group as 5). The disulfonic acid was obtained when the reaction was run a t 0" t o 5 O C. The same authors chlorosulfonated 2-nitrothiophene (39 grams) dissolved in chloroform (100 ml.) by a procedure involving addition of half the solution t o chlorosulfonic acid (93 grams) in chloroform (100 ml.), An equal weight of chlorosulfonic was then added, followed by dropwiee addition of the second half of the solution of thiophene compound. The mixture was refluxed 10 hours. A 74% yield of 5-nitro-3-thiophenesulfonyl chloride was finally obtained. Alkylatcd thiophenes have been sulfonated with chlorosulfonic acid according t o a recent patent (283). In an example, 246 grams of "wax alkylated" thiophene (prepared by reacting unsaturated paraffin wax with thiophene using a synthetic silicaalumina gel catalyst! were mixed with an cqual weight of motor oil, and sulfonated by treatment with chlorosulfonic acid (44.4 grams) for 1 hour a t room temperature, then finally heating t o 100" C. Other examples disclose the sulfonation of wax alkylated dibutyl and mixed a- and 6-monoethylthiophenes by the same procedure. The sulfonic acids were converted t o barium salts used as improved lubricant additives. The sulfonation of dibenzothiophene dialkylated with paraffin wax (using chlorinated paraffin wax and aluminum chloride with dibenzothiophene as detailed), 200 parts dissolved in 400 volumes of chloroform, with chlorosulfonic acid (41.2 parts) by refluxing 21/* hours has been disclosed in a patent (290). The sulfonic acid so obtained (position of sulfonic group not stipulated) was converted t o various metallic salts used 11s improved lubricant additives. I n the above thiophene sulfonations using chloro- or fluosulfonic acid the sulfonyl chlorides or fluorides predominate when using a large excess of sulfonating agent, while use of smaller quantities favors formation of sulfonic acids. NITROGEN COMPOUNDS

The procedure developed by Terent'ev and coworkers for sulfonating various heterocyclic compounds (224), has been extended t o several substituted pyrroles (349, 360)using his standard technique (heating in a sealed tube with pyridine-sulfur trioxide complex for 5 t o 9 hours, in some casks using ethylene dichloride solvent). Compounds thus sulfonated, with yields, are listed in Table VI. Apparently the use of ethylene dichloride as solvent is critical in the case of the 2,5-isomer, since the yields listed were obtained without solvent, while with the solvent no reaction occurred even at a higher temperature.

The mme technique was applied by Terent'ev et al. (345) to indole and methylated indoles. Compounds treated a t various temperatures and yields obtained (as barium salts) are as follows: indole a t 120' C., 90% 2-sulfonate; indole a t 80" C., only the l-sulfonate; 3-methyliiidole (skatole) a t 120" C., 55% 2-sulfonate; 2-methylindole a t 170" C., no carbon sulfonates, only a tar apparently the I-(nitrogen) sulfonate. It is concluded that the first step is formation of the 1-sulfonate, followed by rearrangement to the 2-isomer. 1-Acetylpyrrole was also sulfonated by Terent'ev and Yanovskaya (34.9) with pyridine-sulfur trioxido using his standard technique (heating in a sealed tube with ethylene dichloride solvent a t 100' t o 120" C.). Two disulfonates were obtained, apparently the 2,5- and the 2,4-isomers. %Acetylpyrrole, using the same technique ($51, Mi?),yielded the 3,5-disulfonate and a smaller amount of the 4-sulfonate; with 6% oleum as sulfonating agent a 75% yield of the 4-sulfonate was obtained. These sulfonates weie isolated as barium salts. N o sulfonation of the methyl group was observed in either of these cases, or in the case of 2-acetylfuran discussed above; on the other hand, with 2acetothienone and with methyl aromatic ketones approximately 70% yields of the exocyclic sulfonates were obtained using dioxane-sulfur trioxide as the sulfonating agent.

Table VI. SubRtituted Pyrrole Sulfonated 1-Methyl %Methyl 2,CDimethyl 2,5-Dimethyl 1.2,5-Trimethyl 2,3,5-Trimethyl I-Phenyl 1-o-Tolyl

Sulfonation of Pyrrole Derivatives Mono-

sulfonate,

%

57 54

.. 47

40 25.4

...

45

Disulfonate. Isomer

%

...

... ...

Isomer

... ...

...

11.6 12

3,4 3.4

23

2,4'

... .

I

...

.

Commercial grade 2-picoline wm sulfonated t o 6-methylpyridine-3-sulfonic acid in 5 hours (84, aa opposed t o the 24-hour heating time specified in the literature for the same procedure. The sulfonation is accomplished by heating the picoline (93 grams) with 20 t o 22% oleum (400 grams) a t 220" to 230" C. in the presence of mercury sulfate catalyst (2.5 grams). Carbazole was tetrasulfonated (90% 2,3,6,8-isomer and 10% 1,3,6,&isomer) by adding over 15 hours at 25" C. carbazole (420 kg.) and 65% oleum (1390 kg.) t o a mixture of monohydrate acid (3850 kg.) and 65% oleum (360 kg.). Spent acid wa.s neutralized with lime (369). The preparation of sulfonated carbazole dyestuffs was disclosed in two recent Swiss patents. I n one case (187) 1,4-di(pnaphthy1amine)anthraquinone (50 pai-ta) was added slowly with stirring t o chlorosulfonic acid (500 parts) at 5" to 10" C., then acetic anhydride (90 parts) was added at thc same temperature over a/, hour. Upon working up the reaction mixture, a yellowish brown wool dye was obtained, The product was a carbazole derivative containing one acetyl group and two sulfonic groups, the sulfonyl chloride groups being hydrolyzed to sulfonic groups in the process. In the second case (189), the same quinone was bonzoylated and then oxidized to the carbazole which was isolated as a n orange brown powder; this was sulfonated to contain between one and two sulfonic groups with a mixture of 100% sulfuric acid and 20% oleum a t 0" to 10" C. The entering position of the eulfonic groups was not specified. Sulfonated carbazole dyestuffs have also been prepared by heating the carbazole made by oxidative ring closure of l-benzoylamino-4-(p-benzeneazoanilino)anthraquinone (20 parts), with 20% oleum (385 parts) a t 95" C. for l/* hour. The sodium 8alt of this sulfonic acid dyes wool reddish-brown shade8 (298). I n the course of a study of the chemistry of indoxyl red Io-@'indoyl)p-indolone ], Seidel(306) noted sulfonation of this material,

September 1951

INDUSTRIAL AND ENGINEERING CHEMISTRY

together with formation of the corresponding cr-(p'-oxindolyl)-pindolone, upon heating with aqueous potassium bisulfite. The reaction was as follows, R representing the indolone group:

I

H

A The possible mechanism of this interesting sulfonation was not discussed. PHTHALOCYANINE DERIVATIVES

German practice in the manufacture of various phthalocyanine sulfonic acids by 1. G. Farbenindustrie a t Ludwigshafen has been reviewed ( 7 ) . Conclusions were drawn as follow? for the sulfonation of copper phthalocyanine: (1) only the monssulfonic acid is formed with 4oy0 oleum below 20" C.; (2) disulfonic acid is formed a t 51' C. using a 15-hour reaction time; ( 3 ) above 60" C. considerable trisulfonic acid is formed: (4) t o introduce four sulfonic groups, chlorosulfonic a i d is used a t 150" C. for 4 to 5 hours. This procedure is also used for tetrasulfonation of metalfree phthalocyanine as well as the nickel and aluminum derivatives. This chlorosulfonation procedure yields t'he tetrasulfonyl chloride as the primary product, which may readily be converted t o the corresponding tetrasulfonamide with ammonia. Sulfonation of metal-free phthalocyanine is best carried out, with a mixture of 24% oleum and chlorosulfonic acid a t 100' C. Preparation of sulfophthalocyanines from the corresponding sulfophthalic acid salts is discussed. Sulfonation of phthalocyanincs and the related tetrabenzoporphins has been studied by Linstead and Weiss (282). Metal-free phthalocyanine wae sulfonat,ed a t 80' C. with 30% oleum t o yield a product with between 3 and 4 sulfonic groups. Degradation studics established sulfonation as occul i n g at the 4-position of the benzene ring. Attempted regeneration of phthalocyanine by acid hydrolysis of the d f o n i c group was unsuccessful, as was alao attempted conversion of the Rulfonic arid to a phenol by caustic fusion. Sulfonated phthalocyanine is more susceptible to oxidation than the unsulfonatcd compound. Sulfonated copper phthalocyanine p!,epared from 4-sulfophthalic anhydride (by heating with ureY and copper salts) was found to be different in color from that obtnincd by direct sulfonation of copper phthalocyanine; it is suggested that direct sulfonation may yield some of t,he 3-isomer. Tetrabenztriazop3rphin was sulfonatcd at, room temperature with 15y0oleum to yicld 20% of a mixture of the mono- and disulfonic acids (mostly mono-): 30% oleum gavc complete decomposition. Zinc tetrabenzporphin, on the other hand, was succesafully sulfonated with 30% oleum. The sulfonated products were more susceptiblc to oxidation than the starting materials. The monosulfonntion of copper phthalocyanine (10 parts) by heating slowly over a n 8-hour period in an iron sulfonator t o 140' C. with exactly 100.O~o sulfuric acid (100 parts), followed by immediate cooling to room temperat,ure, has been disclosed in an example in a recent pat.ent (118). MECELLANEOUS

A series of twenty new heterocyclic sulfonyl chlorides has been prepared (2ment of ,V-(ol-ethylhexyl)ethanolamine (43 grams) in ethylene dichloride solvent (86 grams) with chl rosulfonic acid (32 rams). The reaction mist,ure was stirrcd 2 hours a t 20" C., a k e r which the desired sulfonic acid was filtctrcd Off.

Sulfation of an alkylphenol polyglycol ether with sulfamic acid, as operated a t Hochst, has been descrilml ( 4 6 ) . The condensixt,ion product of dodecylphenol with 3 niolcs of ethylene oxide (1504 kg.) is heatcd to 100' C. in a.n enameld kettle, and sulfamic acid (600 kg.) is added over 1 hour, during which time thc temperature rises to 120' to 125' C., at which t,empcrature the reactants are held for an additional hour t o complete the reaction. The reaction product (ammonium salt) is converted to the sodium salt by heating with 33y0 aqueous sodium hydroxide a t 70" C. for 12 hours. Although the use of sulfamic acid has been prefwred German pract,ice for sulfation of such ether alcohols, chlcrosulfonic acid may be used, as shown in the following report of work done a t Hochst in 1935 (162). -4n alkylated phenol pent,agIycol ether (molecular weight 500, from ethylene oxide and phenol alkylated with dimerized isohexylene-isoheptylene mixture), 75 kg., is dilut,ed with an equal weight of methylene chloride, and chlorosulfonic (22.5 kg 125% of theory) is added a t 5' to 15" C. The reaction mixture'is stirred 3 hours and blown with air to remove hydrogen chloride. After neutralization with aqueous caustic soda, the solvent is carefully removed by distillation. Although a satisfactory product is thus obtained, difficulty is encountered with foaming and hydrolysis of the chlorinated solvent during its removal.

2046

INDUSTRIAL AND ENGINEERING CHEMISTRY

The same ether alcohol (250 grams) is sulfated by heating with sulfamic acid (58 grams, 20% excess).at 110' to 120' C. for l l / z hours. The product is then heated with aqueous caustic soda at 80' C. until no more ammonia is evolved.

Vol. 43, No 9

mixture separates into two layers, one of which contains an organic sulfate in 70 t o 80'% concentration. Preparation of aqueous solutions of sodium alkyl sulfates with decreased tendency t o crystallize or gel has been patented (259), involving substitution of sodium by potassium to a final molar ratio of 1 potassium to 3 sodium. This may be done either by neutralizing with the appropriate mixture of bases, or by adding potassium sulfate t o a solution of the sodium alkyl sulfate. Acid or neutral aqueous solution of alcohol sulfates has been decolorized by treatment with less than 1% chlorine, nitrogen dioxide, or a mixture of both (255).

I n the sulfation of long-chain primary and secondary alcohols (methyl undecyl carbinol and long chain monoester of propylene glycol are cited specifically) with sulfamic acid (59),the required excess of the sulfating agent tends t o render the product unstable in water solution. The products may be stabilized by removal of the excess sulfamic acid, involving in one caNe (59) heating, for example, with ammonium sulfamate, acetamide, or methyl iso-

Table IX. Sulfonating and Sulfating Agents A Aliphatic Saturated paraffins and cyclopara5ns Olefins and acetylenes Saturated aldehydes and ketonea Aromatic Monocyclic Benzene Toluene Detergent alkylates Misc. alkylated benzene hydrocarbons Polystyrene Phenolic compounds Misc. benzene derivatives Polycyclic Naphthalene and derivatives Anthracene derivatives Misc. polycyclic compounds Heterocyclic Fursne and thiophene derivatives Nitrogen compounds Phthalocyanines Petroleum fractions Fatty acids, oils. esters, eto.

1

..

1

'1 ,.

.. 1 ..

Sulfonating and Sulfating Agents= C D E F G H

B

. . . . . .

1 2

4

..

12

.. ..

..

..

..

1

.. ..

..

1

..

1

1 3

.

5 2

9

2 2 3 3 2 9 11

.. 'i 'i '2

12 1 10

10 1 2

.

.

.

..

'5

..

'i

..

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . 3 . . . . . . . . 7 . . . . . . . . . . . . 2 1

. . . . . . . .

. . . . . . . .

. . . . 1 1 . . . . . . . . . .

. . . 2 . 5 . 1

..

. . . . . .

.

3

..

,. 1

1

.

2

s 4

2

J

. . . . . . . .

. . . . . . . .

4

I

i

,

2

.

3

.

. . . .

. . . . . . . .

. .

. .

.

.

.

. . . . . .

.

.

2 .

5

.

'

i

.

. . . .

. . . . . . . .

1

.. .

1 1

. . . . . . . . . . . .

14

10 . 5 ,. 3 11 4 . . . . . . . .

1

. . . 1. 4

. . . .

2

.

.

1

,

.

2 1 .

Sulfamation 2 . . 1 . . 1 . . . . 0 A = SO8 gas, B = SOa with solvent. C = SO8 with dioxane, ,D = 60s with pyridine, E = 803 (other adducts). F = oleum, G = sulfuric acid, H = ohlorosulfonic, I = sulfamic acid, J = miscellaneous.

butyl carbinol. A second method of eliminating the excess sulfamic acid involves treatment of the product with sodium nitrite or nitrogen tetroxide (60). Two recent patents have been noted on improved solvent neutralization procedures for preparing sodium dodecyl sulfate. I n one case (9'7)thc acid reaction mixture is poured in a fine stream at 25' C. into sodium (or potassium) hydroxide dissolved in methanol, the weight of which is ten times the quantity of organic sulfate t o be neutralized. The product sulfate, which is filtered and dried, is about 98% pure. The filtrate, containing about 20% of dissolved organic sulfate, is recycled. The other patent (49) cites the addition of Pulfated dodecyl alcohol t o acetone in which is suspended anhydrous sodium sulfite. The water of neutralization is removed as sodium sulfate decahydrate, which is insoluble and immediately precipitates; the acetone solvent is distilled to recover the desired organic sulfate. This process avoids hydrolysis of the organic sulfate noted in the usual aqueous neutralization procedures. A Japanese patent (20%)discloses production of a high active sodium cetyl (hexadecyl) sulfate from a product containing 5570 sodium sulfate. The mixture is dissolved in 10 volumes of water at 40' t o 50' C. and let stand overnight at 0" C. Cetyl sulfate containing less than 5% sodium sulfate crystallizes from the solution. An improved procedure for concentrating aqueous solutions of organic sulfates has been patented (58). A 25% aqueous solution of sodium secondary alkyl sulfates (8 to 18 carbon atoms) is mixed with a n equal weight of a potassium sulfite solution. The

CYCLIC COMPOUNDS

The sulfation of estradiol %benzoate (147) and of testosterone (148) by Holden and coworkers has been described. In the former case, the alcohol, dissolved in a mixture of pyridine and chloroform, was added t o chlorosulfonic acid a!so dissolved in pyridine-chloroform; the mixture was then held at room temperature for 68 hours, after which the chloroform was distilled, and the residue was dissolved in methanol and neutralized with aqueous sodium carbonate t o yield sodium estradiol-3-benzoate17-sulfate. I n the second case, the alcohol-pyridine-chloroform solut.ion was added t o the mixture of chlorosulfonic acid, pyridine, and chloroform; the reaction mixture then stood at room t,emperature for 48 hours, and the chloroform was distilled. Neutralization with methanolic sodium hydroxide yielded sodium testosterone sulfate. Production of the leuco sulfates of v a t dyestuffs has been the subject of a number of recent patents assigned to Imperial Chemical Industries. Reduction of the vat dyestuff (keto form) t o the leuco (hydroxy form) and sulfation of the leuco form are often conducted in one step. A wide variety of sulfating agents has been employed, the following being mentioned in specific examples: pyridine-sulfur trioxide (62); acid amides of secondary amines (dimethyl formamide, formyl piperidide, tetramethyl adipaniide, diethylacetamide, N-formyl morpholide, N-dimethylbcnzamide, tetramethylurea, dimethylurethane, N-methylacetanilide, N-methylphthalimidine, acetopiperidide) with sulfur trioxide or various compounds containing it (methyl and ethyl

September 1951

I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY

chlorowlfonates, chlorosulfonic acid) (6'3);quatei nary ammonium chlorosuiionates, the preparation of which is detailed in several examples by the following type reaction ( 9 8 ) :

The diethyl sulfide-suifur trioside addition compound was used in one case to prepare the quaternary chlorosulfonates; it was made by slow addit,ion of liquid sulfur trioxide to the cooled sulfide, t,he addit,ion compound separating as a liquid. Other patents on production of leuco sulfates assigned to the Sam? firm have been noted, the sulfating agents being similar: (61, 99, 188, 190-102, 895). Sulfation of leuco vat dyes has been the subject of patents assigned to ot,her firms. In one case (339) the sulfating agent was pyridine (or 2-picoline)-sulfur trioxide. In a second patent (86) pyridine-chlorosulfonic acid was used. The sulfation of phenols in aqueous sodium carbonate solution with trimethylamine-sulfur trioxide has been the subject of a recent study (266). The yield of sulfate decreased with increasing t,emperature, alkalinity, or dilut,ion. Ortho-substit,uted phenols gave lower yields than the metn or para isomers. Salicylic acid yielded hardly any sulfate; bonding of the phenolic hydrogen to the carboxyl group is thought to hinder the react,ion since the desired sulfate was found to be stable under the conditions of attempted reaction. Methyl salicylate, however, can be sulfated using dimethylaniline-chlorosulfonio acid according to a recent patent (265). I n a specific example, methyl salicylate (38.3 kg.) was mixed with dimet,hylaniline (30.5 kg.) and added a t 0" to 30" C. in portions t o dimethylaniline chlorosulfonate made by adding dimethylaniline (41 kg,) t o chlorosulfonic acid (32 kg.) in portions a t below 0" C. The reaction mixture is diluted with ethyl alcohol (300 liters) and neutralized with sodium hydroxide (14 kg.), after which the sodium chloride formed is filtered. Further addition of sodium hydroxide (21 kg.), followed by stirring several hours, yielded the desired disodium salicylsulfate, the methyl group being removed by saponification in this step. Equations are given for each step of the process, and solubilities are given for the product in hot and cold water. CARBQHYDRATES

Carbohydrate sulfates are of current interest from the biochemical standpoint, since heparin, the potenl blood anticoagulant, is such a compound, and also from the industrial standpoint of solubilizing cellulose to obtain sulfates with properties similar to those of the water-soluble gums. The so-called "sulfonated sugars" are obtained with ligninsulfonic acid in the sulfite process for preparing wood pulp (f3). The subject of carbohydrate sulfates has recently been reviewed, with 77 references (96'8). The sulfoethylation of starch, using sodium chloroethane sulfonate and the sulfoalkylation of alkali cellulose with butanc sultone, are discussed above in the Aliphatic section under Sulfoalkylation. The sulfoethylation of cellulose with sodium chioroethane sulfonate has been previously reviewed (625). In all cases the object has been to obtain water-soluble products. Since heparin is not readily available, attempts have been made to prepare eheaper materials of equivalent potency and lack of toxicity by sulfation of cellulose, pectin, chitin, and related materials. A recent pntent (316) discloses sulfation of alginic acid toward this end. Purified alginic acid (1 t o 270 moisture maximum), 9 grams, in dry pyridine (90 ml.) was treated with chlorosulfonic acid (21 ml.) a t 60' C. for 8 hours. The reaction mixture was poured into wat.er, and the pyridinium salts (after filtration) were precipitated by addition of methanol. The pyridinium salts were fractionated to products with varying percentages of sulfur, and were also converted to the sodium salts by treatment with aqueous caustic soda a t pH 9. Charoiiir sulfuric acid, prepnred by a Japanese investigator

2047

(319) has anticoagulant properties similar to heparin, and in many properties is similar to cellulose sulfuric acid. Sodium cellulose sulfate, prepared 11y treatment of ceiirilose with sulfuric acid and cont,aining appiovimateiy 1 sulfate group per 3 anhydroglucose units, has recently been made availatile i n two viscosity grades on an experimental comniercial basis (If). A comprehensive technical bulletin (341) has been made available detailing physical properties, toxicity, viscosity of aqueous solutions, stability in acid and basic mediums, compatibility with various materials, and possible uses. This matserial may compete kvith carboxy methylcellulose as an ingredient of synthetic organic detergents. Thomas (355) discloses an improved process for preparing ccllulose sulfate by treatment of cellulose with a mixture of sulfamic acid and an amide. Mixtures of sulfamic acid and urea are used. Reaction is obtained by heating a t 135' to 140' C. for 30 minutes. The products have about 2% combined sulfur. Tse of sulfamic acid alone gives an inferior product because the cellulose is degraded. The sulfation of cellulose with concentrated sulfuric acid has been studied in a Peries of papers by Kagama and coworkers (197, 198). Topics considered include preparative procedures and stability in aqueous acid and alkaline mediums. Another Japanese investigator ($81 ) has studied the sulfonation of xanthated cellulose in connection with physicochemical studies of viscose spinning.

SULFAMATIIQN An improved process for preparing ammonium sulfamate, involving treatment of pyridine-sulfur trioxide with gaseous ammonia in excess pyridine as solvent,, has been patented (139). Sulfur trioxide gas (20 moles) is passed into technical pyridine (100 moles) a t 10" to 30" 6. Gaseous ammonia (40 moles) is then introduced a t the same temperature. Ammonium sulfamate is crystallized arid filtered in nearly quantitative yield. A4second example discloses uEe of a technical picoline-lutidine coal tar base cut as the solvent in a similar operation. The organic bascs are recycled. Dibutylsulfamic acid has been manufactured by I. G , Farlienpage 8) b y treating dibutylamine (1200 industrie a t Mainkur ($4, kg., 9.3 moles) dissolvcd in o-ch:orotoluene (1200 kg.) with chlorosulfonic acid (260 kg., 2.24 moles). The reaction mixture is neutralized with aqueous casutic soda and the water solution is used as m c h as an intermediate for producing the increasing assistant Leophen KK. Caprolactam sulfate has been prepared by reaction of the lact a m with 15% oleum in carbon tetrachloride solution (64). The product is a waxy hygroscopic solid. In the sulfonation of indole and its methylated derivatives n i t h pyridine-sulfur trioxide, the initial step is postulntcd as format,ion of the l-(nitrogen)suifonic acid, which a t a higher temperature rearranges to the carbon sulfonic acid. A small yield of the N-sulfonic acid together with other products was obtained by Bogdanov and coworkeys (95,34) in treatment of 1-naphthylamine with sodium bisulfite-mcrcury oridc.

SUMMARY OF SULFONATING AND SULFATING AGENTS A tabulation is presented in Table I X of the sulfonating and sulfating agents as used in the examples and processes cited in this review. Only compounds of sulfur trioxide were considered; special reagents such as bisulfites, chlorine-sulfur dioxide, etc., are not included. Chlorosulfonic acid is cited only as used for sulfonation, as opposed to its use for chlorosulfonation. As expected, oleum and sulfuric acid were most generally applicable. Pyridine-sulfur trioxide is noteworthy for its fairly broad applicability as a special sulfonating and sulfating agent.

I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY

2048

M E C H A N I S M AND KINETICS The mechanism of aromatic sulfonation continues to be the subject of active study. The drawing of general conclusions has been made difficult by the many complicating variables involved, including the equilibrium nature of the reaction, type of sulfonation solvent, and the easy formation of complexes between sulfonic acids and sulfur trioxide. Conclusions to date on aromatic sulfonation mechanism have been ieviewed and discussed at some length in two recent books. One of these (S), covrring work to early in 1950, notes t h a t sulfonation, although i t resembles nitration and halogenation in many respects, differs notably regarding reversibility and the sensitivity of orientation t o changes in reaction temperature. The kinetics of aromatic amine sulfonation and of the Jncobsen rearrangement is reviewed in some detail. The second review (284) considers past rn well as current theories of sulfonation mechanism u p to early in 1949; nitration and sulfonation are compared. Brand (38,39) has studied experimentally the kinetics of aromatic sulfonation with oleum u p t o 33% over the temperature range 0” t o 45” C., the aromatic compounds studied being p nitrotoluene, nitrobenzene, p-tolyltrimethyIammonium inethyl sulfate and phenyltrimethylammonium methyl eulfate. The kinetics are shown to be consistent, with the assumption t h a t the governing step is:

SOsH+

+ ArH = ArSOaH + H +

A study of the extinction curves of benzenesulfonic acid and its derivatives has been made and compared with those of diphenylsulfone and its derivatives (209). Sulfonic acids can undergo mesomerism only t o a small extent, while the sulfones can undergo mesomerism since their sulfone groups are attached on both sides t o phenyl nuclei. A comprehensive study of the rate of bcnzene sulfonation, previously reviewed and available only as a microfilm (reference 45, %Vi), has now been published as a journal article ( 7 2 ) .

IDENTIFICATION AND A N A L Y S I S The general principles involved in analyzing commercial higher alcohol sulfates have been reviewed (145). Details for the titrimetric determination of sodium alkyl sulfates in dilute aqueous solutions using cetylpyridinium bromide in the presence of methylene blue sulfate have been published (138). Long-chain alkyl sulfates (octadecyl) may be analyzed even in very dilute solution (204) by formation of a complex with rosaniline or p arosaniline hydrochloride, which is then extracted with a mixture of chloroform and ethyl acetate; the solution is then assayed colorimetrically. The sensitivity of the methol increases with chain length of the alkyl group. Reutenauer (286)has published details of the analysis of a commercial alkyl sulfate. An improvement in the benzidine method for determining the sulfate value of sulforicinates has been published (2’93). Analysis of alkyl aryl sulfonate detergents has been studied extensively. Wallin ( 3 g 4 ) developed and calibrated an improved direct colorimetric procedure for dodecylbenxene sulfonates, which is also considered applicable t o other surface active sulfonates and sulfates. This procedure involves substitution of basic fuchsin for methylene blue in the procedure developed by Jones (reference 183, 293). A comparative study has been made (287) of water determination in commercial alkyl aryl sulfonates by four procedures: azeotropic distillation with benzene, the same w i t h toluene, desiccation at 95’ C., and infrared analysis. The first two methods are recommended as rapid and sufficiently accurate. The same author (288) has also studied methods of determining unsulfonated hydrocarbons, and three methods of determining the sulfonated organic content. The best method was evaporation of an aliquot of the alcoholic solution remaining

Vol. 43, No. 9

after extraction of unsulfonated hydrocarbons with petroleum ether of specified boiling range. An improved volumetric-evolution method has been developed for determining carbonates in soaps and synthetic detergents (312). A study has been made (b89) of methods of determining inorganic constituents (sodium carbonate, sodium bicarbonate, sodium sulfate) in thirteen commercial allcyl aryl sulfonate detergents; the classical methods were found to be the most reliable. Analytical methods have been published for Mersol (crude sulfonyl chlorides produced by chlorosulfonation), for Mesolate (sodium sulfonate detergent produced by saponification of Mersol), and Nekal (alkylated naphthalene sulfonate) (163,164, 176,186). Oxidative polarography has been shown (363)to be of value in analysis of pyrrole sulfonic acids. A quantitative analytical testing procedure for differentiating among seven types of synthetic tanning agents has been published (52). A thermometric titration procedure has been developed for differentiating among aromatic sulfonamides (309). German analytical methods for B wide variety of sulfonic acids, as produced in Germany largely as dye intermediates, have become available (168,169,l@). Picon has described a n analytical method for ammonium ichthyol sulfonate, a thiophcne derivative of pharmaceutical interest (270). The homogeneity of sulfonated pyrroles has been demonstrated by the leaching method (364).

ACKNOWLEDGMENT The authors wish t o acknowledge the assistance of John Siliato in preparing t h e drawings and are indebted to T. A. Wallace for a number of helpful suggestions.

LITERATURE CITED (1) Adams, C. E., and Johnson, C. E. (to Standard Oil Co. of Indiana), U. 5. Patent 2,523,490 (Sept. 26, 1950). (2) Adams, D. A. W., et al., U. S. Dept. Commerce, OTS Rept., P B 85687 (1946). (3) Alexander, E. R., “Principles of Ionic Organic Reactions,” New York, John Wiley & Sons, 1950. (4) Allen, C. F. H., Crawford, J. V., Sprague, R. H., Webster, E. R., and Wilson, C. F., J . Am. Chem. Soc.. 72, 585-8 (1950). (5) Allmen, S. V., and Eggenberger, H. (to Sandoz Ltd.), L7. S. Patent 2,517,613 (Aug. 8, 1950). (6) Anderson, C. C., Kgl. NorRke Videnskab. Selskabs, Forh , 22, No. 18, 70-5 (1949); pub. in English (1950). (7) Andrews, D. B., et al., U. S. Dept. Commerce, OTS Rept , P B 85172 (1948). (8)Angelopulo, A. I., Leglcaya Prom. 10, No. 1, 28-9 (1950). (9) Anon., C h a . Enp. News, 28, 3665 (1950). (10) Anon., C h a . I d s . , 67, 245-6.256 (1950). (11) Ibid., pp. 555-6. (12) Anon., Soap, Perfumery, & Cosmetics, 23, N o . 4 , 383-6 (1950). (13) Aries, R. S., and Pollak, A., Chimie & industrie, 63, 494-501 (1950). (14) Asahara, T., Kawasaki, T., Kitawaki, I., Kimot, R., and Mural. M., J . SOC.Org. Spthefzc Chem. (Japan). 7 , 31-46 (1949). (15) Asinger, F., U. S. Dept. Commerce, OTS Rept., P B 95601, Frames 2964-80 (1941). (16) Asinger, F., and Naggatz. Ibicl., Frames 3020-34 (1941). (17) Asinger, F., Schmidt, and Streigler, Ibid., P B 850 (1941). (18) Asinger, F., et al., Ibid., P B 95601, Frames 3044-63 (1941). (19) Azienda Colori Nazionali Affini ( M . Bertin and A . h l o t t a , inventors), Ital. Patent 429,199 (Jan. 19, 1948). (20) Bachmann, W. E., and Klemm, L. H., J . Am. Chem. Soc., 72, 4911-15 (1950). (21) Baer, M. (to Monsanto Chemical C o . ) , U. S.Patent 2,533,210 (Dec. 12, 1950). (22) Ibid., 2,533,211 (Dec. 12, 1950). (23) Baird, W., U. S. Dept. Commerce, OTS Rept., P B 28754 (1946). (24) Ibid., P B 34004 (BIOS Final Rept. 2 3 9 ) (1946). (25) Ibid., P B 79578 (BIOS Final Rept. 1151) (1946). (26) Baker Castor Oil Co., Technical Digest No. 22. (27) Balfe, M. P., Kenyon, J., and Searle, C. E., J . Chem. S o c , 1950,3309-12.

September 1951

INDUSTRIAL AND ENGINEERING CHEMISTRY

Beilstein, F. K., “Beilstein’s Handbuch der organishchen Chemie,” 4th ed., 2nd supplement, Vol. 11, 286 pp., Berlin, Julius Springer, 1950. Bergel, F., Morrison, A. L., and Rinderknecht, H., J . Chem. SOC.,1950, 659-63. Billbrough, S., U. S. Dept. Commerce, OTS Rept., P B 63627 (1946). Bircher, J. R., Jr. (to Interlake Chemical Corp.), U. 9. Patent 2,485,352 (Oct. 18, 1949). Blumer, M. (to L. Sonneborn Sons, Inc.), Ihid., 2,486,373 (Nov. 1, 1949). Bogdanov, S. V.. and Migacheva, I. B., J . Gen. Chem ( U S . S.R.), 20, 124-33 (1950). Bogdanov, S. V., and Pavlovskaya, G. I., Thid.. 19, 1374-7 (1949). Bolgar, L., Brit. Patent 644,451 (Oct. 11, 1950). Boyer, R. P. (to Dow Chemical Co.), U. S. Patent 2,500,149 (March 14, 1950). Bradley, H. W. (to E. I. du Pont de Nemours & C o . ) , Zbid., 2,507,088 (May 9, 1950). Brand, J. C. D., J. C h m . Soc., 1950, 997-1003. Ibid., pp. 1004-17. Bransky, D. W-., and Lemmon, N. E. (to Standard 011Co. of Indiana), U. S. Patent 2,479,202 (Aug. 16, 1949). Ibid., 2,530,757 (Nov. 21, 1950). Brit. Intelligence Objectives Subcommittee, U. S. Dept. Commerce, OTS Rept., PB 99921. Brod, J. S . (to Procter & Gamble Co.), U. S. Patent 2,529,537 (Nov. 14. 1950). Brod, J. S.; and ’Henry, R. A. (to Procter & Gamble Co.), Ibid., 2,529,539 (Nov. 14, 1950). Brown, B. K. (to Standard Oil Co. of Indiana), Ibid., 2,521,147 (Sept. 5, 1950). Brown, C. B.. U. S. Dept. Commerce, OTS Rept.. PB 63822 (1946). Brown, S. M., and Thomaon, G. H., J . Chem. SOC.,1950, 1019. Burwell, R. L., Jr., J . Am. Chem. SOC., 71, 1769-71 (1949). Busch, G. L., U. S. Patent 2,511,043 (June 13, 1950). California Research Corp., Brit. Patent 645,129 (Oct. 25, 1950). California Research Corp., Lewis, A. H., Ettling, A. C., Brooke, L. F., Elwell, W. E., and Meier, R. L., Fr. Patent 948,938 (Aug. 16, 1949). Chen, P. S., J . Am. Leather Chenb. Assoc., 45, 531-6 (1950). Chinoin gyogysaer es vegyeszeti termekek gyara r. t. (Keresty and Wolf, inventors), Swiss Patent 261,21 (Aug. 1, 1949). Chwalinski, S., Przemysl Chem., 27, 644-5 (1948). Ciba A.-G., Australian Patent 166,222 (June 26, 1950). Ciba A.-G., Swiss Patent 261,367 (Aug. 16, 1949). Cislak, F. E. (to Reilly Tar and Chemical Corp.), C . S. Patent 2,508,904 (May 23, 1950). Clahsen, F. h.,Dutch Patent 65,460 (March 15, 1950). Clark, J. R., and Malkemus, J. D. (to Colgate-Palmolive-Pet Co.), U. S.Patent 2,493,444 (Jan. 3, 1950). IM., 2,493,445 (Jan. 3, 1950). Coffey, S.,Driver. G. VV., and Fairweather, D. A . W. (to Imperial Chemical Industries, Ltd.), Brit. Patent 605,617 (July 28, 1948). Coffey, S.,Driver. G. W., and Fairweather, D. A. W-.(to Imperial Chemical Industries, Ltd.), U. S. Patent 2,504,806 (April 18, 1950). Coffey, S., Driver, G. W., Whyte, D. A., and Irving, F. (to Imperial ChemicaI Industries, Ltd.), Ihid., 2,506,580 (May 9, 1950). Coffman, D. D., Raasch, M. S., Righy, G . W., Barrick, P. L., and Hanford, W. E., J . O r g . Chem., 14, 747-53 (1949). Cohen, C. A. (to Standard Oil Development Co.), U. S . Patent 2,497,152 (Feb. 14, 1950). Zbid., 2,532,997 (Dec. 5, 1950). Zbid., 2,535,784 (Dec. 26, 1950). Cook, W. A., and Cook, K. H., J . Am. Pharm. Assoc., Sci. Ed., 38,239-41 (1949). Cope, J. W., and Scott, J. W., Jr. (to California Research Corp.), U. S. Patent 2,531,324 (Nov. 21, 1950). Cowdrey, W, A., and Hinshelwood, C. N., J . Chem. SOC.,1946, 1036-50. Creditanstdt-Bankverein, Austrian Patent 165,675 (April 11, 1950). Crooks, R. C.. and White, R. R., Cheni. Eng. Progress, 46, 24957 (1950). Cross, A. H. J., and Gerrard, W., J . Chem. Soc., 1949, 2686-9. D’Alelio, G. F. (to General Electric Co.), U. S. Patent 2,366,007 (Doc. 26, 1944). Dammers, H. F., Ibid., 2,522,212 (Sept. 12, 1950). Dauphin, R. J., Fr. Patent 954,920 (Jan. 3, 1950). \

~~

2049

(77) David, V. W.,J . Inst. Petroleum, 35, 563-73 (1949). (78) Day, H. M. (to American Cyanamid Co.), U. 9. Patent 2,477,328 (July 26, 1949). (79) Ihid., 2,497,05&(Feb. 7, 1950). (80) Day, H. M., and De Hoff, R. L. (to Anicrican Cyanamid Co.), U. S. Patent 2,522,569 (Sept. 19, 1950). (81) Debus, G., U. S. Dept. Commerce, OTR Rept., PB 70332, Frames 675-678 (1936). (82) Diena, M., “Gli Olii Solfonati,” Milan, Editoriale Italiana, 1949. (83) Douglnss, I. B., and Johnson, T. B., J . Am. Chem. Soc., 60, 1486-9 (1938). (84) Dudley, J. R. (to American Cyanamid Co.),U. S. Patent 2.527,300 (Oct. 24, 1950). (85) Duesel, B. F,, and Scudi, J . V., J . A m . Chem. SOC.,71, 1866-7 (1949). (86) Durand & Huguenin A.-G., Swiss Patent 249,123 (March 1, 1948). (87) Eagle Oil & Shipping Co., Ltd., Mitchell, R. G., Tait, H. C., Gilbert, H. C., David, C. L., and Shell Refining & Marketing Co., Ltd., Brit. Patent Application 9764/47. (88) Edeleanu G.m.b.H., U. S. Dept. Commerce, OTS Rept., PB 91150 (1941). (89) Edgar, J. L., Ckem. A g e (London), 63, 55-7 (1950). (90) Ekstrom. G., Svensk. K e m . Tid., 62, 113-20 (1950). (91) Enkvist, T., and Riigglund, E., Svemk Paperstidn., 53, 85-93 (1950). (92) Erdtman, H., Reseal-ch, 3, 63-7 (1950). (93) Erdtman, H., U. S. Dept. Commerce, O T S Rept., PB 94791 (1945). (94) Erdtman, H., Lindgren, B. O., and Pettersson, T., Acta Chem. Scand., 4, 228-38 (1950). (95) Ernsberger, M.L., and Pinkney, P. A. (to E. I. du Ponl.~de Nemours & Co.), U. S. Patent 2,503,253 (April 11, 1950). (96) fitablissements Phillips & Pain, S. A., Permutit Co., Ltd., Holmes, E. L., and Holmes, L. E., Fr. Patent 950,990 (Oct. 12, 1949). (97) Fabriai, F., Ital. Patent 433,792 (April 15, 1948). (98) Fairweather, D. A. W., and Imperial Chemical Industries, Ltd., Brit. Patent 630,459 (Oct. 13, 1949). (99) Zbid., 633,501, 633,502, 633,504, 633,505 (Deo. 19, 1949). (100) Faith, W. L., Keyes, D. B., and C h r k , R. L., “Industrial Chemicals,” John Wiley & Sons, iYew York, 1950. (101) Feil. D. A. (to Allied Chemical & Dye Corp.), U. S. Patent 2,525,024 (Oct. 10, 1950). (102) Fessler, Vi‘. A. (to Allied Chemical & Dye Corr).),Ihid., 2,510,466 (June 6, 1950). (103) Fields, P. R. (to Standard Oil Co. of Indiana), Ibid., 2,502,618 (April 4, 1950). (104) Fierz-David, H. E., and Blangey, L., ”Grundlegende Operationen der Farhenchemie.” 5th ed., Vienna, Julius Springer, 1943. (105) Flachsmann, E. (Arthur Molinari, inventor), Swiss Patent 258,294 (May 2. 1949). (106) Ibid., 266.362 (April 17, 1950). (107) Ibid., 267,115 (June I , 1960). (108) Frank, R. L., Berry, R. E., arid Shotwell, 0. L., J . Am. Chem. SOC., 71, 3889-93 (1949). (109) Frazier, D. (to Standard Oil Co. of Ohio), TJ. S.Patent, 2,499,377 (March 7, 1950). (110) Friedman, H. L., and Braitberg, L. E. (to Pyridium Corp.). Ibid., 2,477,731 (Aug. 2, 1949). (111) Frohmader, 9. H. (to Research Products Corp.), B i d . , 2,529,602 (Nov. 14,1950). (112) Fu, L.-C., and Chen, C.-H., J . Chem. Eng. China, 15, 72-80 (1 948). (113) Garrett, W. H., U. S. Dept. Commerce, OTS Rept., PB 110409 (1946). (114) Geigy, J. R., A.-G., Swiss Patent 245,642 (Aug. 1, 1947). (115) Ibid., 255,303 (June 15, 1948). (116) Geigy, J. R., SOC.Anon, Fr. Patent 54,372 (March 19, 1950) (addition to 870,784). (117) Ghamrawi, M. A,, and Said, F., J . Pharm. Phumacol., 1, 75760 (1949). (118) Giambalvo. V. A. (to Interchemical Gorp.). U. S . Patent 2,526,345 (Oct. 17, 1950). (119) Gilbert, E. E., and Otto, J. ;2. (to Allied Chemical & Dye Corn.). Zbid.. 2.506.417 (May 2 , 1950). (120) Ibid.,2,515,444 (July 18, 1950). (121) Gilman, H., and Blatt, A. H., “Organic Syntheses,” Collective Vol. I. 2nd ed.. New York. John Wiley & Sons, 1941. (122) Goebel, M. T. (to Canadian Industries, Ltd.. to E. I. du Pont de Nemours & Co.), Can. Patent 464,164 (April 4, 1950). (123) Gold, M. H. (to Visking Corp.), U. S. Patent 2,510,281 (June 6 , 1950). .

I

INDUSTRIAL A N D ENGINEERING CHEMISTRY Ibid., 2,510,282(June 6, 1950). Greene, L. W., U. S. Dept. Commerce, OTS Rept., P B 101458 (1950). Greene, R. B. (to Allied Chemical & Dye Corp.), U. S. Patent 2,504,517(April 18, 1950). Groggins, P. H., “Unit Processes in Organic Synthesis,” 3rd ed., New York, McGraw-Hill Book Co., 1947. Grosse, A. V., and Snyder, J. C. (to Houdry Process Corp.), U. 5.Patent 2,492,983(Jan. 3, 1950). Gundermann, E., Seifen-Ole-Fette-Wachse, 76, 255-7, 322-5 (1950). Halbedel, H. S.,and Heath, J. C. (to Harshaw Chemical Co.), U. S. Patent 2,480,465(Aug. 30, 1949). Hale, D. K., and Reichenberg, D., D~kcussionsFaraday SOC., 1949,No. 7,79-90.

Harlan, J. L. (to Standard Oil Development Co.), U. S. Patent 2,509,863(May 30,1950). Harman, D. (to Shell Development Co.), Ibid., 2,504,411 (April 18,1950). Harris, J. 0. (to Monsanto Chemical Co.), Ibid., 2,527,880 (Oct. 31, 1950). Harvel Corp., Brit. Patent 627,920 (Aug. 18, 1949). Ibid., 637,741 (May 24, 1950). Ibid., 645,062(Oct. 25, 1950). Hekker, T.,and Schets, A. W. M., Chem. Weekblad, 45, 582-3 (1949). Helberger, J. H., Manecke, G., and Heyden, R., Ann., 565, 22-35 (1949). Henricsson, T.,Swed. Patent 126,426 (Oct. 18. 1949). Henry, R. A., and Brod, J. 5. (to Procter & Gamble Co.), U. S. Patent 2,529,538(Nov. 14,1950). Herold, P., Smeykal, K., Asinger, F., and Wolf, W. (to I. G. Farbenindustrie A.-G., assignor to General Aniline & Film Corp., and the said General Aniline & Film Corp., and the Secretary of State of Canada, as Custodian under the Trading with the Enemy Act, assignors to Chemical Developments of Canada, Ltd.), Can. Patent 464,020 (March 28,1950). Hill, E. J., School Sci. and Math., 50,259-69 (1950). Hinkel, L. E., and Summers, G. H., J . Chem. Soc., 1949, 2854-6. Hintermaier, A. H., Angew. Chem., A60, 158-9 (1948). Hofmann, K. (to Ciba Pharmaceutical Products, Inc.), U. S. Patent 2,506,594(May 9, 1950). Holden, G. W.,and Bromley, R., J . Am. Chem. SOC.. 72, 3807-8 (1950). Holden, G. W., Levi, I., and Bromley, R., Ibid., 71, 3844 (1949). Hollander, C. S. (to Rohm & Haas Co.), U. S. Patent 2,480,859 (Sept. 6,1949). Hollander, C. S., and Bock, L. H. (to Rohm & Haas Co.). Ibid.. 2.535.677(Dec. 26. 1950). Ibid., 2,635,678(Dec. 2 6 i950). ’ Houdry Process Corp., Brit. Patent 632,820 (Dee. 5, 1949). Hoyt, L. F., U. 5. Dept. Commerce, OTS Rept., P B 3868 (1945). Huggett, W. E., and Duffin, G . F. (to Howards & Sons, Ltd.), U. S. Patent 2,468,670(April 26, 1949). Hunter, W. (to Celanese Corp. of America), Ibid., 2,529,533 (Nov. 14,1950). Huntress, E. H., and Autenrieth, J. S., J . Am. Chem. SOC.,63, 3446-8 (1941). I. G. Farbenindustrie A,-G. (to Badische Anilin- & Sodafabrik), Fr, Patent 953,774 (Dec. 13, 1949). I. G. Farbenindustrie A.-G., U. S. Dept. Commerce, OTS Rept., P B 17680 (1922-44). Ibid.’. P B 17692 (1946). Ibid.: P B 30086,‘Frames 274-6 of FIAT Microfilm Reel C26, P B 12272 (1932). Ihid., P B 32536. Ibid., PB 70183 (1938-46). Ibid., P B 70420,Frames 628-45 (1940). Ibid.; P B 73503 (1926-42). Ibid., P B 73911,Frames 4816-18 (1935). Ibid., P B 74120,Frames 14-17 (1938). Ibid., P B 74051 (1935-45). Ibid., P B 90388 (1941-43). Ibid., P B 91097 (1940-44). Ibid., P B 91100 (194142). Ibid., P B 91157 (1943). Ibid., P B 91199 (1943). Ibid,, P B 91355 (1937-45). Ibid., P B 93678 (1943). Ibid., P B 93680 (1943). Ibid., P B 95600,Frames 4977-5002 (1942-43). Ibid., P B 95600,Frames 5198-5203 (1942).

Vol. 43, No. 9

(178)Ibid., P B 96587 (1940-44). (179) Ibid., P B 96623. (180)Ibid., P B 96627. (181)Ibid.. P B 96834 (1940). (182j Ibid.: P B 98165 (i940-44). (183)Ibid., P B 100046 (1941). (184)Ibid., P B 100055 (1940). (185)Ibid., P B 100937 (1946). (186)Ibid., P B 102210 (1913-47). (187) Imperial Chemical Industries, Ltd., Swiss Patent 261,870 (Sept. 1, 1949). (188)Ibid., 261,369 (Aug. 16, 1949). (189)Ibid., 261,871 (Sept. 1, 1949). (190) Ibid., 262,281(Sept. 16,1949). and Fairweather, (191) Imperial Chemical Industries, Ltd., Coffey, S., D. A. W., Fr. Patent 952,190(Nov. 10,1949). (192)Imperial Chemical Industries, Ltd., Coffey, S., Fairweather, D. A. W., and Hathway, D. E., Ibid., 952,309 (Nov. 15, 1949). (193)Ivanov, D., and Ivanov, C., Compt. rend., 227, 1379-81 (1948). (194)Jackson, D. R., and Langdon, W. K. (to Wyandotte Chemicals Corp.), U. S. Patent 2,486,417(Nov. 1, 1949). (195) Johnson, T.B., and Sprague, J. M., J. Am. Chem. SOC.,58, 1348-52 (1936). (196) Jones, G. D., and Barnes, C. E. (to General Aniline & Film Corp.), U. S. Patent 2,515,714(July 18,1950). (197)Kagawa. I., J. SOC.Textile Cellulose I n d . J a p a n , 1, 677-84 (1945). (198) Kagawa, I., and Katsuura, K., Ibid., 2, 1-7 (1946). (199) Kamlet, J. (to Mathieson Chemical Corp.), U. S. Patent 2,514,955(July 11, 1950). (200) Kamlet, J. (to Pittsburgh Coke & Chemical Co.), Ibid., 2,536,751 (Jan. 2, 1951). (201) Kanyaev, N. P., Zhur. Fiz. Khim., 24, 154-65 (1950). (202)Kao Soap Co., Inc., Japan. Patent 155,372(March 9,1943). (203)Kaplan, W. (to Sun Chemical Corp.), U. S.Patent 2,495,105 (Jan. 17, 1950). (204)Karush, F.,and Sonenberg, M., Anal. Chem., 22, 175-7 (1950). (205)Kenyon, R. L., and Boehmer, N., IND. ENG.CHEM.,42, 144655 (1950). (206)Kharasch, M. S,,Rchenck, R. T. E., and Mayo, F. R., J . Am. Chem. SOC.,61,3092-8 (1939). (207)Kimura, S., and Hayano, K. (to Tanabe Drug Co.), Japan. Patent 174,188 (Nov. 29,1946). (208)Kircher, J. E.,S o a p S a n i t . Chemicals, 26,No. 12,48-50 (1950). (209)Kiss, A., and Csetneky, E., Acta Univ.Szigediensis, Acta Chem. et Phys., 2, 30-2 (1948). (210)Kleinholz, M. P. (to Sinclair Refining Co.), U. S. Patent 2,499,997(March 7,1950). (211)Klimko, V. T., and Mikhalev, V. A,, J . Applied Chem. ( U S . S.R.), 22,524-6 (1949). (212)Komarewsky, V. I., and Ruther, Ur. E., J . Am. Chem. SOC., 72, 5501-3 (1950). (213)Koelov, V. V., and Egorova, A. A . , Doklady A k a d . Nauk S.S.S.R., 57, 467-70 (1947). (214) Kroepelin, H., Opitz, W., and Freiss, W., Erd6Z u. Kohle, 2, 498-500 (1949). (215) Kreikalla and Woldan, U. S. Dept. Commerce, OTS Rept., P B 604 (1941). (216) Kulka, M., J. Am, Chem. SOC.,72, 1215-18 (1950). (217)Kunin. R.. and Myers, R. J., “Ion Exchange Resins,” ITew York, John Wiley & Sons, 1950. (218) Leslie, R., Mfg. Chemist, 21,417-19 (1950). (219) Lew, H. Y.,and Noller, C. R., J . A m . Chem. Soc., 72,5715-17 (1950). (220) Lieber, E.,and Cashman, A. F. (to Standard Oil Development Co.), U. S. Patent 2,459,440(Jan. 18, 1949). (221)Ibid., 2,483,499(Oct. 4, 1949). (222) Linstead, R. P., and Weiss, F. T., J . Chem. SOC.,1950,2975-81. (223) Lisk, G. F., IND.ENQ.CHEM.,40, 1671-83 (1948). (224) Ibid., 41, 1923-34 (1949). (225) Ibid., 42, 1748-60 (1950). (226)Lockwood, W.H.(to E. I. du Pont de Nemours & Co.), U. S. Patent 2,503,279(April 11, 1950). (227)Ibid., 2,503,280(April 11, 1950). (228)Lodge, F.,Wardleworth, J., and Imperial Chemical Industries, Ltd., Brit. Patent 635,955(April 19,1950). (229) Lvnch. K. L. (to American Cyanamid Co.). U. 5. Patent 2,507,030(May 9, 1950). (2301 McCutcheon, J. W., Soup Sanit. Chemicals, 26, No. 3, 91, 93 (March 1950). (231) Maeda, H., J. SOC.Textile Cellulose I n d . J a p a n , 2,8-13 (1946). (232) Malkemus, J. D. (to Colgate-Palmolive-Peet Co.), U. S. Patent 2,462,758 (Feb. 22, 1949). .

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(233) Malkemus, J. D., Ramsay, J. R., and Potter, D. P. (to ColgatePalmolivc-Peet Co.), Ibid., 2,452,943 (Kov. 2, 1948). (234) AIamalis, P., and Petrow, V., J . Chem. SOC.,1950, 703-11. (235) Mapstone, G. E., Petroleum Refiner, 29, No. 11, 142-50 (1950). (236) hlarkham, A. E., Peniston, Q. P., and McCarthy, J. L., J . Am. Chem. SOC.,71,3599-601 (1949). (237) Mattson, R. W. (to Union Oil Co. of Calif.), U. S. Patent 2,523,582 (Sept. 26, 1950). (238) Melander, K. H. A,, Savo, G. E., Johanson, T. I. (to Sulfitaktiebolaget), Can. Patent 466,880 (July 25, 1950). (239) hlendel, J . L., and Visser, D. W., Proc. SOC. Ezptl. B i d . M ( d . , 73, 541-2 (1950). (240) Mengel, U. S. Dept. Commerce, OTS Rept., PB 75463 (1936). (241) hlerrill. R. G., Soap Sanit. Chemicals, 26, No. 3. 48-9, 70 (1950). (242) Miller, R . J. (to Calif. Research Corp.), U. S. Patent 2,523,707 (Sept. 26, 1950). (243) Moy, P. W., and Karash, W.P. (to The Harshaw Chemical Co.), Ibid., 2,528,902 (Xov. 7, 1950). (244) Silsson, E. 0. (to Hoganas-Bellesholms Aktiebolag), Swed. Patent 125,775 (Aug. 9, 1949). (245) Xippon Chemical Industries Co., Japan. Patent 156,639 (h.lay 24, 1943). (246) Sishirawa, K., J . SOC.Chem. I n d . J a p a n , 45, Suppl. binding 366-8 (1942). (247) Ibid., 46, Suppl. binding 4-5 (1943). (248) Ibid p. 221 (1943). (249) Sishizawa, K., and Nagura, G., Ibid., 45, Suppl. binding 320-2 (1942). (250) Nopco Chemical Co., Brit. Patent 642,836 (Sept. 13, 1950). (251) N. V. de Bataafsche Petroleum Maatschappij, Brit. Patent 626,377 (July 14, 1949). (252) I b i d . , 628,014 (hug. 19, 1949). (253) N. V. de Bataafsche Petroleum Maatschappij. Dutch Patent 65,718 (Play 15, 1950). (254) X. V. de Bataafsche Petroleum Maatschappij, Fr. Patent 941,471 (Jan. 12, 1949). 12551 Ibid.. 941.950 (Jan. 25. 19491. (256) Ibad., 943,488 (‘hfarch 9, 1949). (257) Ihad., 952,196 (Xov. 10, 1949). (258) Ibid., 953,277 (Dee. 2 , 1949). , Ibid., 000,484 (April 19, 1950). Ono, K., J . SOC.Org. Sunthetic Chem. J a p a n , 7, 12-14 (1949). Oronite Chemical Co., “Alkane Detergent Raw Material Produced by Oronite Chemical Co.,” 20 pp., 1950. Orthnei, L., Angew. Chem., 62A, 302-5 (1950). O t t , .iB. . (to Monsanto Chemical C o . ) , U. S. Patent 2,518,249 i.luz. 8 1950). Overucrger, C. G., Baldwin, D. E., and Gregor, H. P., J . Am. Chsm. SOC.,72, 4864-6 (1950). Parrod, J., and Armand, V. (to SociQtBGenkrale d’Applications Therapeutiques “Theraplix”), U. S.Patent 2,478,834 (Aug. 9, 1949). Parrod, J., and Robert, L., Compt. rend., 230, 450-2 (1950). Pennsylvania Salt Manufacturing Co., “Pennsalt Sulfonyl Fluorides,” 7 pp.. 1950. Percival, E. G . Ir,,Quait. Revs. (London),3, 369-84 (1949). Pctersen, S.,Ann., 562, 205-29 (1949). Picon, M., Ann. pharm. franG., 7, 90-5 (1949). Plapper, J., ColloqiLiumsber. Inst. Gerbereichem. Tech. Hochschide Darmstadt, KO. 5 , 60-79 (1949). Poggi, A. R., Ann. cliim. applicnta, 37, 402-11 (1947). Poggi, A. R., Ravai, A , and Niccolini, P., Arch. intern. pharmacodynamie, 83, 15-32 (1950). Poggi, A. R., Serchi, G., and Fabiani, G., Chimica (Milan), 4, 381-3 (1949). Potolovukii, L. A , , Zavodskaya Lab., 15, 1152-7 (1949). Proell, W. A. (to Standard Oil Co. of Indiana), U. S. Patent 2,518,639 (Aug. 15, 1950). Ibid., 2,525,942 (Oct. 17, 1950). Proell, W. A,, and Hill, B. L. (to Standard Oil Co. of Indiana), I b i d . , 2,502,619 (April 4, 1950). Proell, W . A , , and Shoemaker,, B. H. (to Standard Oil Co. of Indiana), Ibid., 2,505,910 (May 2, 1950). Prokhorov, F. G., and Korneyeva, hl. G., Izuest. V T I , 16, NO. 6, 1-6 (1947). Ralston. A. I\‘.,“Fatty Acids and Their Derivatives,” New York, John W l e y 8. Sons, 1948. Reichspatentamt, Berlin, U. S. Dept. Commerce, OTS Rkpt., P B 83606, FIAT Microfilm Reel F 148, Frames 6157-7166 (1937-45). Reiff, 0. M., and dndress, H. J., Jr. (to Socony-Vacuum Oil Co., Inc.), U. S.Patent 2,518,372 (AUK.8, 1950). Remick, A. E., “Electronic Interpretations of Organic Chemistry,” 2nd ed., New York, John WWey & Sons, 1949. j

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(285) Reppe, J. W., and Ufer, H., U. S. Dept. Commerce, OTS Rept., PB 75279, enlargement print of Frames 1958-62 of FIAT Microfilm Reel C 61, P B 17658 (1935). (286) Reutenauer, G., Bull. mens. I T E R G (Inst. tech. Qtudes recherches corps gras), 4, 61-74 (1950). (287) Ibid., pp. 197-9. (288) Ibid., pp. 199-204. (289) Ibid., pp. 255-7. (290) Richter, F. P., and Fuller, E. W. (to Socony-Vacuum Oil Co., Inc.), U. S. Patent 2,527,335 (Oct. 24, 1950). (291) Riess, W., Seifen-Ble-Fetle-Wachse, 76, 103-4 (1950). (292) Roberts, J. B., Gage, H. B., and Brautoheck, C. H. (to E. I. du Pont de Nemours & Co.), U. S. Patent 2,528,320 (Oct. 31, 1950). (293) Robinet, M., and Chevron, N., Bull. SOC. chim. Belges, 58, 32430 (1949). (294) Roblin, R. O., Jr., and Clapp, James W., J . Am. Chem. Soc., 72, 4890-2 (1950). (295) Robson, A. C., Slinger, F. H., and Imperial Chemical Industries, Ltd., Brit. Patent 633,492 (Dec. 19, 1949). (296) Rudolf & Co., Fr. Patent 951,506 (Oct. 27, 1949). (297) Rust, F. F., Stiles, A. R., and Vaughan, W. E. (to Shell Development Co.), U. S.Patent 2,519,403 (Aug. 22, 1950). (298) Ibid., 2,524,084 (Oct. 3, 1950). (299) Saunders, B. C., J . Chem. Soc., 1950, 684-7. (300) Scalera, M. (to American Cyanamid Co.), U. S. Patent 2,499,003 (Feb. 28, 1950). (301) Schmerling, L. ( t o Universal Oil Products Go.), U. S. Patent 2,524,086 (Oet. 3, 1950). (302) Schumacher, U. S. Dept. Commerce, OTS Rept., PB 58835, enlargement print of Frames 734-7 of FIAT Microfilm Reel C 28, P B 14998 (April 1938). (303) Schwartz, A. M., and Perry, J. W., “Surface Active Agents, Their Chemistry and Technology,” Xew York, Interscience Publishing Co., 1949. (304) Schwoegler, E. J. (to Wyandotte Chemicals Corp.), U. S. Patent 2,533,517 (Deo. 12, 1950). (305) Segessemann, E., and Molnar, N. M., Ibid., 2,515,803 (July 18, 1950). (306) Seidel, P., Chem. Ber., 83, 20-6 (1950). (307) Seymour, G. W., and Saivin, V. S. (to Celanese Corp. of America), U. S.Patent 2,501,831 (March 28, 1950). (308) Seymour, G. W., Salvin, V. S.,and Jones, W.D. (to Celanese Corp. of America), Ibid., 2,511,547 (June 13, 1950). (309) Shafer, H., and Wilde, E., 2. anal. Chem., 130, 396-401 (1950). (310) Shishido, X., and Uno, S. (to Mitsubishsi Chemical Industrial Co.), Japan. Patent 175,501 (Jan. 23, 1948). (311) Shreve, R. N., and Lloyd, F. R., Ixu. ENG.CHEW,42, 811-17 (1950). (312) Shuck, N. hl., and Koester, W.X., J. Am Oil Chemists’ Soc., 27, 321-3 (1950). (313) Small, L. D., Bailey, J. H., and Cavallito, C. J., J . Am. Chem. SOC.,71, 3565-6 (1949). (314) Smith, J . M.,Jr. (to American Cyanamid Co.), U. S.Patent 2,502,897 (April 4, 1950). (315) Snell, F. D., Chem. Eng. News, 29, 36-8 (1951). (316) Snyder, E. G. (to Wyeth, Inc.), U. S.Patent 2,508,433 (May 23, 1950)

Snyder; J. C., and Grosse, A. V. (to Houdry Process Corp.), Ibid., 2,493,038 (Jan. 3, 1950). Societe pour l’ind. chim. a BBle, Brit. Patent 581,985 (Oct. 31, 1946). Soda, T., Chem. Researches ( J a p a n ) , 1, Biochem., 51-74 (1948). Solodar, L. S.,and Shevchenko, Z . N., J . Applied Chem. (U.S.S.R.), 22, 508-17 (1949). Ibid., pp. 874-81. Sperling, R., J . Chem. SOC.,1949, 1925-7. Ibid., pp. 1932-8. Ibid., pp. 1938-9. Ibid., p. 1939. Sprague, J. M. (to Sharp & Dohme, Inc.), U. 9. Patent 2,531,367 (Nov. 21, 1950). Sprague, J. M., and Johnson, T. B., J . A m . Chem. SOC.,59, 1837-40 (1937). Ibid., pp. 2439-41. Spryskov, A. A . , and Apar’eva, N. V., J . Gen. Chem. (U.S.S.R.), 19, 1576-22 (1949). Standard Oil Development Co., Brit. Patents 628,002 and 628,003 (Aug. 19, 1949). Stenerson, H., Chem. Eng. N e u s , 27, 3450 (1949). Stervart, D., and McXeill, E., Chem. A g e , 63, 48-50 (1950). Stuewe, A. H., and Lollar, R. M., J . Am. Leather Chemists’ ASSOC., 45, 195-203 (1950). Sugiyama, S., Japan. Patent 155,985 (April 10, 1943). Sun Chemical Corp., Brit. Patent 640,924 (Aug. 2, 1950).

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RI., “The Organic Chemistry of Sulfur; Tetracovalent Sulfur Compounds,” New York, John Wiley & Sons, 1944. (337) Suter, C. M., Brtir, R. K., and Bordwell, F. G., J . Org. Chem., 10,470-8(1945). (338) Sveroceske Tukove Zavody (Drive Jiri Schicht), Narodni Podnik, Brit. Patent 636,650(May 3, 1950). (339)Taras, J. (General Aniline & Film Corp.), U. S. Patent 2,507,944 (Mav 16.1950). (340) Tatum; W: W.’, and ’Imperial Chemical Jndustries, Ltd., Brit. Patent 609,585(Oct. 4,1948). (341) Tennessee Eastman Corp., “Sodium Cellulose Sulfate,” 1950. (342) Terent’ev, A. P., Vestnik Moskov. Univ., 1947,No. 6,9-32. (343) Terent’ev, A. P., and Dombrovskii, A. V., Doklady A k a d . N a u k S.S.S.R.,67,859-62 (1949). (344) Terent’ev, A. P., and Dombrovskii, A. V., J. Gen. Chem. (U.S.S.R.). 19. 1467-71 (1949). (345) Terent’ev, A: P., Golubeva; S.K., and Tsymbal, L. V., Ibid., 19,781-3 (1949). (346) Terent’ev, A. P., Kazitsyna, L. A., and Suvorova, S. E., Ibid., 19,1951-4 (1949). (347)Terent’ev, A. P., Kasitsyna, L. A., and Turovskaya, A. M., Vestnik Moskov. Univ.. 3, 159-60 (1948): J. Gen. Chem. (U.S.S.R.), 20, 185-7 (1950). (348) Terent’ev, A. P.,and Volynskii, N. P., J . Gen. Chem. (U.S.S.R), 19, 784-6 (1949). (349)Terent’ev, A. P., and Yanovskaya, L. A., Ibid., 19, 538-43 (1949). (350)Ibid., pp. 1365-8. (351)Ibid., pp. 2118-22. (352) Terent’ev, A. P., and Yanovskaya, L. A,, Vestnik Moskov. Univ., 3, No. 10,155-7 (1948). (353) Terent’ev, A. P., Yanovskaya, L. A., and Terent’eva, E. A., Daklady A k a d . N a u k S.S.S.R., 70,649-51 (1950). (354)Terent’ev, A. P., Yanovskaya, L. A., and Yashunskii, V. G., J . Gen. Chem. (U.S.S.R.), 20,510-13 (1950). (355) Thomas, J. C. (to E. I. du Pont de Nemours & Co.), U. S. Patent 2,511,229(June 13,1950). (356) Thurston, J. T. (to American Cyanamid Co.), U. 5. Patent 2,525,247(Oct. 10, 1950). (357)Tomita, M.,Yamada, H., and Hosumi, K., J . Pharm. SOC. J a p a n , 69,403-4 (1949). (358) Treibs, W., and Lorens, I., Chem. Ber., 82,400-5 (1949). (359) Truce, W. E.,and Alfieri, C. C., J . Am. Chem. SOC.,72,2740-3 (1950). (360)Truce, W.E.,and Gunberg, P. F., Ibid., 72,2401-3 (1950). (361) Ueno, S., J. Nippon Oil Technol. Soc., 3, No. 1/2, 101-13 (1950). (362) Ufer, H., and Hecht, 0. (to I. G. Farbenindustrie A.-G.), U. S. Patent 2,140,569(Dec. 20,1938). (363) Ufimtsev, V. N., Doklady A k a d . Nauk S.S.S.R.,60, 23941 (1948). (364) Umhoefer, R. R. (to Buffalo Electro-ChemicaI Co.), U. S. Patent 2,499,702(March 7, 1950). (365) United States, Office of Military Government for Germany, U. S. Dept. Commerce, OTS Rept., PB 85172823 (1938). Sutcr, C.

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(366) Ibid., P B 85172838 (1947). (367)Ibid., P B 85172~51(1947). (368)Ibid., P B 85172~54(1938). (369)Ibid., PB 85172~58(1947). (370) Ibid., PB 85172~122. (371)Ibid., PB 851728151. (372)Ibid., PB 85172~196(1945). (373)Ibid., PB 851728206. (374) Ibid., PB 851729285, (375)IbicE., PB 851728347. (376) United States, Office of the Quartermaster General, Military Planning Division, Research & Development Branch, U. S. Dept. Commerce, OTS Rept., PB 95789, pp. 16, 23, 28 [Leather Series, Rept. No. 2,compiled by Kathleen Johnson] (1948). (377) United States, Tariff Commission, “Synthetic Organic Chemicals; United States Production and Sales, 1949,”Washington, D.C., 1950. (378) Universal Oil Products Co., Belden, D. H., and Bloch, H. S., Brit. Open Specification 23489/48. (379) Universal Oil Products Co., Bloch, H. S.,Mavity, J. M., and Belden, D. H., Ibid., 23488/48. (380) Valochneva, E. P., J . Gen. Chem. (U.S.S.R.), 19, 1529-34 (1949). (381) Vitalis, E. A. (to American Cyanamid Co.), U. S. Patent 2,535,972(Dec. 26, 1950). (382)Vlugter, J. C., Chem. Weekblad, 45, 198-9 (1949). (383) Vold, M. J., and Mertes, R. W. (to Union Oil Co. of Calif.), U. S. Patent 2,514,733(July 11, 1950). I Wallin, G.R., Anal. Chem., 22, 616-17 (1950). 1 Wardleworth, J., and Imperial Chemical Industries, Ltd., Brit. Patent 635,104 (April 5, 1950). 1 Watkins. F. M. ( t o Sinclair Refining - Co.), U. 8. Patent 2.529.523 (Nov. 14,1950). Ibid., 2,529,524(Nov. 14,1950). Weber, J. E., J . Chem. Education, 27,384 (1950). Weisburger, J. H., Weisburger, E. K., and Ray, F. W., J . Am. Chem. Sac., 72,4253-5 (1950). Wilson, C.E. (to Union Oil Co. of Calif.), U. S. Patent 2,499,710 (March 7, 1950). Winkelmueller, D., U. S. Dept. of Commerce, OTS Rept., P B 76032~6. Ibid., PB 7603287 (1946). Wojahn, H.. and Wuckel, H., Pharm. Zentralhalle, 87, 97-102 (1948). Yakubovich, A. Ya., and Zinov’ev, Yu. M., Uspekhi K h i m , 16, 581-98 (1947). Young, F.G. (to Union Carbide and Carbon Corp.), U. S. Patent 2,511,423(Junc 13,1950). Yura. 5.. Jauan. Patent 174.470 (Feb. 3. 1947). Yura; S.; anh Hara, K., J . Chem.‘Soc. Japan, i n d . Chem. Sect., 51, 155-6 (1948). RECEIVED June 16, 1951.

End of Fourth Annual Unit Processes Review (Reprints of this or the preceding Unit Processes Reviews may b e purchased for 50 cents each from the Reprint Department, American Chemical Society, 1155 Sixteenth St.,

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