Friedel-Crafts Reactions mg
PHILIP H. GROGGINS’and SAMUEL B. DETWILER, JR.,
BUREAU
OF
AGRICULTURAL AND INDUSTRIAL CHEMISTRY, U. S. DEPARTMENT OF AGRICULTURE, WASHINGTON, D. C.
T o judge horn the number of reports and diversity of syntheses, Friedel-Crafts reactions still hold the interest of many investigators. A number of familiar names continue to be associated with this Field of research. Korshak in the U.S.S.R., lllari in Italy, and Pajeau in France have made new contributions dealing with the mechanism of Friedel-Crafts reactions. Of particular interest are thermodynamic studies b y Dilke and coworkers in England which appear to have practical implications, in addition to throwing new light on this aspect of the subject. The preparation of chlorinated hydrocarbons b y a number of similar condensations in the presence of Friedel-Crafts catalysts has been reported b y workers in the United States.
T
HE Friedel-Crafts reaction continues to be a proving ground for theories regarding t h e mechanism of chemical reactions. This is due largely t o the slow motion action of the catalysts which provides a n opportunity to study the ionization complexes thereof as well as other reaction phenomena such as isomerization, polymerization, migrations, and condensations. MECHANISM OF REACTION Korshak and Lebedev ( I8) have continued their fundamental studies on the mechanism of the catalytic action of aluminum chloride. They attribute the action of aluminum chloride and related Friedel-Crafts catalysts t o the formation of the dimer, A1&16, which on reorientation has the highly dipolar structure, AIC12f.AlCln-, which in turn induces strong polarization in reactant molecules. These investigators believe this to be the important step in the usual aromatic reactions catalyzed by metal halides, including the formation of a complex between benzene and aluminum chloride. I n other mechanism studies involving the reaction of benzene with trichloroethylene, Korshak and coworkers ( 1 9 ) obtained polynuclear products which are identical t o those obtained in a similar reaction of l,l-diphcnyl-2-chloroethylenewith benzene. I n both instances, treatment of reaction mass with dilute hydrochloric acid followed by stcam distillation of the organic layer gave a chlorine-free residue, C46Ha, from which no individuals could be crystallized. On dry distillation, cleavage of the hydrocarbon residue occurred with the formation of diphenylmethane and crude anthracene. Illari ( l a ) , in continuing his investigations on the mechanism of Friedel-Crafts reactions, refers t o prior reports of Norris and Sturgis ( 2 7 )on the condensation of aliphatic alcohols:
+
CgHSOH
+ AIC18 --f
CtHbOH
+ CeHe + AlCl~+CzHsCsHs + HC1 + AlOHClz
CzHsOH.AIC1, + CzHsOAlClz HCl + CzHsC1 AlOHClz
+
as well as t o the papers of Huston and Friedemann (I0,11 ) pertaining to the condensation of benzyl alcohol: Ce,HsCHzOH
+ AIC1a
c‘. --+
above 40”
CoHsCHzCI (25 to 30%)
Because benzyl chloride is obtained only when temperatures of 40” C. or above are used, Illari believes t h a t i t does not represent a n intermediate product. H e found t h a t when benzyl alcohol was added slowly t o anhydrous aluminum chloride in ice-cold ether, no benzyl chloride was formed. The solid residue of reaction, when decomposed with ice water and acidified with hydrochloric 1 Present address, Chemical Division, National Production Authority, Washington 2 5 , D. C.
yielded C.33Hb60.
Po13benzY1 alcohol,
The mechanismshown by
Equations 1 t o 3 was suggested. The reviewers do not believe t h a t these studies in adversely on the work of the previous investigators. The importance of such factors as temperature, nature of solvent, and polarity of solvent cannot be overlooked. When thpse reactions are carried out a t temperature and other conditions that permit the escape of a n intermediate volatile alkyl or aralkyl halide, these will constitute the major end products. If conditions favor the retention of the halide or its carbonium ion-aluminum chloride complex-then continued reaction with the formation of large complex molecules is favored and is t o be expected.
ROH
+AICls - HCI
ROAlCI,
R’CH2CR”R”’OH
- OAlCl
tAICI3 -------f
-HCI
R ’CH~CR”R”’OA1CIz R‘CH :C R ” R ” ’
+A~CII
-AI(OH)CIz
---+
+ (2e.H~ +R’CH2CCJIsR”R”’
(3)
I n similar studirs involving thc reaction of aryl carbinols with aromatic hydrocarbons in the presence of aluminum chloride, Ungnade and Crandall (4%) found t h a t benzyl alcohol and diphenyl carbinol can act as carbon monoxide donors in the presence of excess catalyst t o give cyclic hydrocarbons. Thus, benzyl alcohol in benzene gave a 52Yo yield of anthracene; with toluene under similar conditions, a 64.7% yield of dimethylanthracenes was obtained; and diphenylmethane gave 35.5y0of a mixture of 2,6- and 2,7-dibenzylanthracenes. Illari (IS) also has studied the mechanism of the FriedelCrafts condensation of aldehydes with aromatic hydrocarbons. Experiments using benzaldehyde with aluminum chloride in ether and carbon disulfide indicate that condensation takes place through the transformation of the -CHO group into a
H
salified and chlorinated primary alcohol group, -C.OAICI1. c1 This is the type reaction which, as shown previously, characterizes the condensation of various alcohols with aromatic compounds. When benzaldehyde is added t o aluminum chloride suspended in carbon disulfide, the reaction is exothermic and a complex, BzH.A1C13.CS1, is obtained which is unstable and decomposes under atmospheric conditions with the evolution of hydro1970
INDUSTRIAL AND ENGINEERING CHEMISTRY
September 1951
prn chloride. Refluxing a carbon disulfide suspension of thc addition complex, followed by distillation and decomposition of the residue, resulted in recovery of the original aldehyde. A similar experiment involving the addition of benzene also gave no reaction. When, however, the addition complex is treated with benzcxie and equimolar weights of aluminum chloride in carbon disulfide, hydrogen chloride is evolved and anthracene is obtained from the residue>. I n technical condensations of alcohols or aldehydes, molar ratios of aluminum chloride are needed to make the original complex, and an excess over this amount is required to form the active carbonium ion. An interest.ing condensation of aldehydes has been reported by X u r a i (26). Iu the reaction of chloral, CCl,CHO, with ehlorobenzene to make D D T , it was found that as the ratio of chloroiwnzene was increased, both addition and dehydration reactions started a t the eame time. The reaction products were p-CIC6I€,CH(OH)CCl3, (CI(36H4)2CHCC13, and [(p-C1CbH4)&Hl2. Jj-hen 2, 5, or 10 moles of chlorobenzene were used per mole of c*hloral,the yields of DDT were 15, 16, and 26%, respectively. Rothstein and Saville (51-35) have made a comprehensive study o f the reaction betn.een aromatic compounds and derivatives of t i ~ ~ t i a r acids, y particularly pivaloyl chloride, (CHS)BCCOCI. \Then tertiary acid halides are used in the Friedel-Crafts reaction with aromatics, hyilrocarbons are generally obtained with the liberation of carbon monoxide. On the other hand, aryl a,m-dialkylpropionic and -butyric acid derivat,ives yield the cyclic ketones normally expectrd. By the choice of a suitable aromatic conipound, it, is possible t o synthesize a ketone by reaction with aliphatic tertiary acids, Thus, when alkylbenzenes are used, mixtures of ketone and hydrocarbon are formed (Sg), The yield of ketone is greatest with toluene and ethylbenzene and least with tert-buty lbenwne. Studies of thP kinetics of tlhereaction between pivaloyl chloride and bcnzcne in thc presence of aluminum chloride indicate t h a t there is a straigllt-line relation between time and the log of the concentration of pivaloyl chloride (33,S 4 ) ! and the first-ordcr constant deduced therefrom is independent of the concentrations Qf both the halide and the hydrocarbon but varies with the square of the aluminum chloride eoncent,ration. Thus, the rate-determining stage of hJ,drocarbon formation is either that of formation of the complex b e h e e n pivaloyl chloride and the catalyst or the decomposition thereof. In summarizing their studies on the factors influencing acylat,ionor alkylation of aromatic compounds by derivatives of acids ( 5 5 ) ,Rothstein and Rowland suggest t h a t the stability of the acyl cation (R3C 'CO) determines the relative rates of the two processes. Loss of carbon monoxide results from the formation of an electrophylic carbonium ion (R3C +), which can be substituted in the nucleus, yield an olefin, or undergo rearrangement. In studying migrations in the benzene nucleus effected by acid catalysts, Pajeau and Fierens (30)concluded that the FriedelCrafts reaction is a n electrophylic transformation in which the role of the catalyst (AICI,, FeCI,, or H2SO4) is limited t o the production of the cation, X+,in the following general reaction:
ArH
+ Xfe ArX + H +
where AT is an aromatic group and X a cation such as D+, CH3+, or CHpCO+. T w o factors appear to be involved in the reaction mechanism: a rapid substitution followed by an isomerization and, eventually, a slower intermolecular change. The ratio of ortho, me&, or para isomers that result from the single rapid substitution depends only on their speed of formation. The effect of the catalyst on the activation energy of the second step of a Friedcl-Crafts reaction (isomerization and intermolecular exchange) varies in inverse ratio t o its acidity. Thus, aluminum chloridr, a very strong acid, noticeably lowers this energy of reaction. Conversely, weaker acids such a8 ferric chloride or sulfuric arid decrrasc the speed of the second step
1971
In another investigation (69), Pajeau found that ferric chloride does not catalyze the condensation of primary and secondary alcohols with benzene. Such a reaction can, however, be effected between certain of these alcohols and homologs of benzene as wcll as phenol ethers. Toluene can thus be condensed with iospropyl alcohol, isobutyl alcohol, and benzyl alcohols; ethylbenzene and m-xylene with isobutyl alcohol; and methyl and ethyl ethers of phenol with isobutyl alcohol.
FRIEDEL-CRAFTS CATALYSTS Most of the new information since the 1950 review pertains to patented techniques for recovering and regenerating aluminum chloride sludges. One procedure (262, which is based on wellknown principles, suggests exposure of the sludge to a gaseous olefin and finely divided metallic aluminum a t 50" to 250" C. and 1 to 200 atmospheres. The resulting liquid organoaluminum fraction is treated with hydrogen chloride to obtain the active metal chloride. In another patent, Latchum ( 2 0 ) describes a procedure whereby aluminum chloride sludges are withdrawn continuously or intermittently from the reaction zone for the recovery of hydrogen chloride, a portion of which is then recycled as a catalyst promoter. The remaining sludge is treated with sulfuric acid of 50% concentration to liberate additional hydrogen chloride and is then delivered to a settler, where a portion of th(a spent sulfuric acid is withdrawn and hydrolyzed t o recover organic compounds consisting chiefly of higher alcohols and some sulfonates. The residual aluminum sulfate in the settler is treated with salt a t about 200" C. to supply additional hydrogen chloride for the system. Alternatively ( d l ) , the organic layer from the hydrolysis step and the aqueous layer from which aluminum sulfate may be removed by filtration, are stripped with steam t o recover alcohols and other organic compounds. The bottoms from the stripper pass to a sulfuric acid recovery unit, where aluminum sulfate settles out and is recovered by filtration. The Zapp firm ( 4 7 ) has reported on a modification of the wellknown technique of using metallic aluminum in conjunction with aluminum chloride for reactions involving the condensation of alkyl chlorides. In the preparation of propylbenzene, benzene and propyl chloride in a weight ratio of 100: 10 are passed through a reactor, and unconverted benzene is recycled.
T H E R M O D Y N A M I C S AND KINETICS Dilke et al. (6) have continued their thermodynamic studies on aluminum chloride complexes with aromatic compounds. These workers found that the reaction of aluminum chloride with 0-, rn- , or p-xylene in chlorobenzene proceeded slowly in the absence of impurities to form the molar complex, Me~C6H1.AICI3, a red, viscous oil. From the heat of hydrolysis, the heat of complex formation is calculated to be 30 kg.-cal. The addition compound may be either a pi or polarization complex. The electrical conohm-l/cm.-l a t 25" C.) suggests some ioniductance (2 X zation of the complex. The values of free energy change in the formation of toluene, rn-xylene, and mesitylene by Friedel-Crafts reactions previously reported by Campbell and Eley (3)as 0 i 1 kg.-cal. are corrected to -10.8, -8.4, and -11.1 kg.-cal., respectively. In another investigation, Dilke and coworkers (6) made a survey of heats of mixing of several classes of organic compounds with aluminum chloride. The heats were related to the energy of the coordinate link formed between the electronegative atom in the organic substance (aldehydes, ketones, ethers, and nitrogen bases) and the aluminum chloride. The bond energy appears t o be strongly influenced by the electronegative character of the atom concerned, since it is affected by inductive and resonance effects in the rest of the molecule. Table I shows the relation of heats of mixing Q t o resonance energies (R.E.), dipole moment p and the heat of the reaction, E,:.
INDUSTRIAL A N D ENGINEERING CHEMISTRY
1972
Table
I.
Vol. 43, No, 9
Correlation of Heats of Reaction and Resonance Energies with Electronegative A t o m in Organic Molecule
Organic Molecule
Q. Kg.-Cal.
Benfialdehyde Acetophenone Benzophenone Anisole D&henyl ether n-Butylamine Diethylamine Piperidine Pyridine Quinoline Triethylamine Ammonia Diphenylamine Aniline Iiitrobenzene
24.7 19.2 15.4 8.2 4.1 44 70 57.1 47 8 36.2 24.0
E : , Kg.-Cal.
...
10
... 7.9
39 33 29 22 18 108 84 71 62 50 38 40 24
..
22
Ir
Resonance Ener ies Kg.-%all
Basic Content
2.75 2.9 3.0 1.2 1.1
47 54 93 52
... ... ... ...
(D)
...
1.2
1.17 2.26 2.16 0.9 1.4 1.3 1.5 3.95
The foregoing data reveal no correlation between E: and the dipole moment of the added molecule. There is positive evidrnce, hoa ever, in favor of a relation between E: and the “donor property” of the electronegative atom in the organic molecule. In the condensation of aldehydes and ketones it may be presumed that the donor link is formed by !he oxygen atom of the carbonyl group, -C=O. The value of E,, for benzaldehyde > acetophenone > benzophenone reflects the general reactivity of the carbon) 1 group in this series. The greater bond energy of the aldehj‘tles and ketones suggests that the donor quality of the oxygen in the carbonyl group is greate; than that of the ether group. The generally large values for E , for nitrogen bases over the oxygen compounds probably reflects a true difference in bond energy. I t is in line with the stronger basicity of the nitrogen compounds. The kinetics of the Friedel-Crafts copolymerization of p-chlorost>rene with styrene, p-chlorostyrene, and a-methylstyrene have been investigated by Alfrey and Wechsler (1). In the presence of tin tetrachloride, the copolymer always contains less of the chloro compound than the original mixture. This is true t o an even greater extent for 2,5-dichlorostyrene. Therefore, p-chlorostyrene adds at a slower rate to styrene and p-chlorostyrene carbonium ions than does styrene. a-Methylstyrene is even more reactive than styrene.
ACYLATIONS Smyth and Moran (40)claim an improvement in the customary method of preparing anthraquinone by the cyclization of o-benzoylbenzoic acid. Phthalic anhydride and aluminum chloride are mised in a ball or other mill as described in “Unit Processes in Organic Synthesis” (8), and about 400% of the required benzene is run in. Upon completion of the Friedel-Crafts condensation, the excess benzene is vaporized, and the residual aluminum chloride complex of the keto acid is treated a t about 90’ C. with :ihout 4 molar proportions of 20% oleum. T h e temperature is thvn raised to 110” C. and thus maintained until the evolution of hydrogen chloride ceases. The resultant crude anthraquinone iidmixed with aluminum sulfate is obtained as a dry powder and is discharged into a v a t of water. Yields of about 84% crude anthraquinone are reported. The advantages of the procedure iire not apparent to the reviewers because a t least 3 moles cf sulfuric acid per mole of keto acid (or anthraquinone) are needed to the yields of technical cwmhine with the aluminum chloride; anthraquinone are comparatively low; and advantage cannot be takcn of the opportunity to purify the anthraquinone by controlled partial precipitation from the sulfuric acid used for cyclia:ition. Admittedly, dry hydrogen chloride can be recovered by t h c s suggested process. MMcRite et al. ( 2 5 ) have found that good yields (74.5%) of a,8-(liphenyl-,9-propionic acid can be obtained by condensing diphmylsuccinic anhydride with benzene. The condensation of itaconic anhydride
and maleic anhydride with benzene gives C@H,COCH: C( CHJ)COOH and C6H,COCH: CHCOOH, respectively ( 7 ) . The acylation of phenyl ii 4.1 %io-4 5 1 . 3 x 10-3 tolyl ether with methyl osalyl 2 1 . 7 X 10-9 43 1 . 7 X 10’ chloride, CIOCCOOCH1, in 75 1 . 0 x 10-9 carbon disulfide gives fair yielde 13 6 . 0 x 10-4 0 1 . 8 x 10-5 of methyl (p-tolylo\yphengl) 98 7 . 6 X 10-1‘ 51 3 . 8 X 10-10 glyoxylate (16). Hagemeyer (9) has found that the condensation of ketenes with esters of heto acids in the presence of Friedel-Crafts-type catalj s t s I C R ~ P to the forrimtion of B-lactoiie esters. Shah and Shah ( 3 7 ) prepaictl several aromatic ketones from hydroxybenzoic acids b y Friedel-Crafts acylation, and these were compared with migration products (Fries migration) for verification purposes. Salicylic acid and acetyl chloride in nitrobenzene thus yielded 2-hydro.;y-5-acetylbenzoic acid. Using benzoyl chloride as the acylating agent, 2-hydro~~~-5-benzoylbenzoic acid was obtained. When p-hydro\ybenzoic acid is condensed with benzoyl chloride, the use of carbon disulfide instead of nitrohenzene as solvent is conducive to higher yields of p-benzoxybenzoic acid.
PREPARATION OF C H L O R O H Y D R O C A R B O N S Chlorohydrocarbons which cannot be made directly by halogenation can frequently be prepared by condensations in the presence of Friedel-Crafts catalysts. McBee and Newcomer ( 2 2 ) have thus shown t h a t a chlorinated hydrocarbon of the molecular formula CsHClll can be prepared by condensing octachlorohexatriene, obtained by condensation of hexachloropropene, with trichloroethene in the presence of aluminum chloride or other Friedel-Crafts catalysts at about 25’ C. Schmerling (36) has shown that polyhaloalkanes can be prepared by similar Friedel-Crafts condensations of mono- or polyhalo-mono-olefins with monohaloalkanes. Thus, a 3701, yield of trichloropentane was obtained by condensing n-propyl chloride with dichloroethylene. A 34% yield of 1,2-dibromo-4,4-dimethylhexane was obtained by reacting tert-amyl bromide with allyl bromide. By a similar condensation, 2,2-dichloro-4,4-dimethylpentane is obtained from the reaction of lert-butyl chloride and 2-chloropropene. Detling ( 4 ) has suggested still another Friedel-Crafts condensation for the preparation of chlorinated hydrocarbons. Here, aluminurn chloride and other metal halides are employed for the preparation of saturated monohalohydrocarbons by reacting a dihaloparaffin with an isoparaflb, whereby a transfer of halogen to the unsubstituted hydrocarbon is effected. Using this technique, monochloroheptane can be obtained by reacting 1,2-dichIoro-4,4dimethylpentane and isobutane. Hydrocarbons containing tertiary carbon atoms may replace the isoparaffin in similar halogentransfer reactions. When monohalogenated olefins, such as allyl chloride, are condensed with an excess of tertiary aliphatic halide such as tert-butyl chloride, 1,2-dichloro-4,4-dimethyIpentane is obtained. Wilson and Shih ( 4 6 ) have reported t h a t the reaction of either 1,2,4- or 1,3,5-trichlorobenzene with carbon tetrachloride in t h e presence of aluminum chloride gives a fused mass which on hydrolysis yields the corresponding hexachlorobenzophenone. When chloroform is used instead of carbon tetrachloride, 2,4,5,2’4‘,5~,2~’,4/’,5/’-nonachlorotriphenylmethane is formed. The reported formation of polychlorobenzophenones instead of dichloro-bis-( trichloropheny1)methane is noteworthy.
September 1951
INDUSTRIAL A N D E N G I N E E R I N G CHEMISTRY BUTYL RUBBER
Several patents relating to the condensation and polymerization of isobutylene with a diolefin such as butadiene or isoprene have recently been issued. Such reactions are generally carried out in the presence of a Friedel-Crafts catalyst dissolved in a low-boiling solvent such as methyl chloride a t about -90’ C. Walsh and claim t h a t the addition of small amounts of water Schutze (44,46) (0.02 mole yo)t o the chilled solution of aluminum chloride in methyl chloride results in a greater catalyst efficiency-Le., more polymer is produced per unit weight of aluminum chloride. Presumably, the same results could be obtained by using a commercial Friedel-Crafts catalyst containing traces of moisture or hydrochloric acid or by other obvious means. Van Berg ( 4 9 ) has developed a method and described facilities for continuously polymerizing isobutylene and isoprene in the presence of a Friedel-Crafts catalyst. The procedure involves the circulation of a chilled stream of admixed isobutylene and isoprene in the weight ratio of 53 parts of the former t o 1 part of the latter and continuously and simultaneously introducing into the reactor a chilled solution of methyl chloride, 146 parts by weight containing 0.3% of aluminum chloride. The effluent from the reactor runs continuously to a flash tank from which the unreacted feed stock is removed near the top while the polymer slurry is withdrawn near the base.
I S O M E R I Z A T I O N AND SCISSION W I T H AICla-HCI Studies on the isomerizing and hydrogenating splitting of hydrocarbons with aluminum chloride-hydrogen chloride mixtures have been reported by Koch and Gilfert ( 1 7 ) . Butane, n-pentane, and methylbutane, as well as hexane, isomerize without side reactions in the presence of anhydrous aluminum chloride and much hydrogen chloride. The higher molecular weight paraffins from heptane up, under similar conditions, are rapidly split a t room temperature. The catalyst can cause hydrogen t o be added to the fiasion products. With sufficiently high hydrogen pressure, the formation of a complex compound between unsaturated hydrocarbons and aluminum chloride is decreased or fully suppressed, so that the catalyst activity is maintained for a long time. The preceding work was unknown to Ipatieff and Schmerling when they reported on similar studies (14). These investigators a Is0 found t h a t molecular hydrogen a t superatmospheric presbures markedly modified the action of aluminum chloride on alkanes. When n-pentane was heated with pure aluminum chloride at 125” C. under high hydrogen pressure, no reaction occurred; under nitrogen pressure, autodestructive alkylation to butanes, hexanes, and higher-boiling alkanes occurred] while the catalyst was converted t o a viscous red oil. When hydrogen chloride was used as a promoter for aluminum chloride under hydrogen pressure, 6lY0of the n-pentane was converted to isopentane, the catalyst being recovered unchanged. With water as the promoter under hydrogen pressure, a yield of 73.7% of isopentane wag obtained. Addition of hydrogen chloride as a promoter is not necessary for commercial aluminum chloride, probably because of the presence of HOAIC12, which is either an isomerization catalyst or decomposes under the reaction conditions to yield hydrogen chloride. According t o Baddeley (Z), hydrogen chloride in conjunction with aluminum chloride promotes the Scholl reaction and the intramolecular migration of alkyl groups in phenol homologs, aromatic ketones, and aromatic hydroxyketones. These reactions do not occur or occur at greatly reduced rates, when a stream of oxygen or nitrogen is passed through the reaction mixture. Thus, 4-methyl-lI2-dinaphthyI ketone in chlorobenzene is converted (70%) at room temperature into 4-methyl-9’, 10’-benzo-mesobenzanthrone by the addition of more than a mole proportion of aluminum chloride. When dry oxygen or nitrogen is passed through the reaction mixture, hydrogen chloride is removed and
1973
reaction does not occur; the reaction commences] however, when hydrogen chloride is introduced.
M I S C E L L A N E O U S FRIEDEL-CRAFTS R E A C T I O N S Confirming earlier findings of Norris and Sturgis ( 6 7 ) , Shishido and And6 (59) found that distillation of the polyethylbenaene residue obtained in the preparation of ethylbenzene yielded a fraction consisting of anthracene. In a subsequent study, Shishido (38) showed t h a t the Friedel-Crafts condensation of ethylene with benzene gave not only ethyl-, diethyl- , and triethylbenzenes as well as anthracene, but also some 9,lO-dimethylanthracene. Oda and Ogata (68), on heating diphenylmethane with about 5% by weight of aluminum chloride and fractionally distilling the reaction mass, isolated p-dibenzylbenzene, p-C6H4(CHzCgH,)2. The preceding Japanese studies, which have just been reported in 1701. 44 of Chemical Abstracts, reflect their work during 1941-42. Phenylarsenious dichloride and diphenylarsenious chloride react with acid chlorides and aluminum chloride with the loss of arsenic and the formation of alkylaryl ketones. According to Malinovskil(Zi), this observation may be used as a means for locating the point of arsenic attachment, as the RCO group takes its place. Thus, when phenylarsenioue dichloride, CsH&C12, is treated with isovaleryl chloride under appropriate conditions, a 74% yield of phenyl isobutyl ketone is obtained. Propionyl and butyryl chlorides gave the corresponding phenones under similar conditions. Kirk (16) has developed a Friedel-Crafts synthesis which involves the condensation of an aromatic hydrocarbon and a compound of the type (CH,),C: CHY in which Y is an acetyl group (as in mesityl oxide, (CHS)ZC:CHCOCHI) or a carboxylic acid group. According to this procedure, 4,4’(p-phenyIene)-bi~(4-methy1-2pentanone) is obtained by condensing benzene and mesityl oxide in the presence of hexane as a solvent. I n a similar manner, tetramethyl-4,4’-bis-phenyldipropionic acid is obtained from (CH&C:CHCOOH and diphenyl. In a reaction corresponding to the preparation of @-phenylethyl alcohol from ethylene and benzene, Somerville and Spoerri ( 4 1 ) have condensed a mixture of cis- and trans-butylene oxide with benzene t o obtain %phenyl-3-butanol.
LITERATURE CITED Alfrey, T., Jr., and Wechsler, H., J . A m . Chem. SOC.,70, 4266-7 (1948).
Baddeley, G., J . Chem. SOC.,1950, 994-7. Campbell, H., and Eley, D. D.. Nature, 154, 85 (1944) Detling, K. D. (to Shell Development Co.), U. S. Patent 2.501.597 (March 21. 1950). Dilke, M. H.; Eley, D.’D., and Perry, M. J., Research (London), 2, 538-41 (1949).
Dilke, M . H., Eley, D. D.. and Sheppard, M. G.,Trans. Faraday SOC., 46, 261-70 (1950). Dixon, S., Gregory, H., and Wiggins, L. F.. J . Chem. SOC.,1949, 213942.
Groggins, P. H., “Unit Processes in Organic Synthesis,” 3rd ed., Chap. XII, New York, McGraw-Hill Book Co., 1947. Hagemeyer, H. J., Jr. (to Eastman Kodak C o . ) , U. S. Patent 2,496,791 (Feb. 7, 1950).
Huston, R. C., J . Am. Chem. SOC.,46, 2775-9 (1924). Huston, R. C., and Friedemann, T. E., Ibid., 38, 2527-33 (1916).
Illari, G., Gam. chim. itat., 78, 904-13 (1948). Ibid., 79, 892-905 (1949).
Ipatieff, V. N., and Schmerling, L., IND.ENG.CHEM.,40, 235460 (1948).
Kimoto, S., Sakai, S., and Ohkuma, K., J . Pharm. Soc. Japan. 69, 40Er7 (1949).
Kirk, W., J r . (to E. I. du Pont de Nemours & C o . , Inc.), U. S. Patent 2,497,673 (Feb. 14, 1950). Koch, H., and Gilfert, W., OeE u. Kohte, 30, 413-19 (1949). Korshak, V. V., and Lebedev, N. N., J . Gen. C h a . (U.S.S.R.). 20, 266-70 (1950).
Korshak, V. V., Samplavskaya, K. K., and Andreeva, M. A., Ibid., 19, 690-5 (1949).
Latchum, J. W., Jr. (to Phillips Petroleum Co.), U. S. Patent 2,486,484 (Nov. 1, 1949).
INDUSTRIAL AND ENGINEERING CHEMISTRY
1974
(21) Ibid., 2,486,485 (Nov. 1 , 1949). (22) hfcBee, E. T., and Newcomer, J. S. (to U. S. A., represented by Atomic Energy Commission), U. S. Patent 2,506,428 (May 2, 1950). (23) iMcRae, J. A., Bannard, R. A. B., and Ross, R. B., Can. J. Research, 28B, 73-82 (1950). :24) Malinovskii, M. S., J. Gen. Chem. (U.S.S.R.), 19, 130-3 (1949). (25) hlavity, J. M. (to Universal Oil Products Co.), U. S. Patent 2,517,692 (Aug. 8, 1950). (26) Murai, H., J . Agr. Chem. SOC.J a p a n , 23, 35-7 (1949). (27) Norris, J. F., and Sturgis, €3. M., J . Am. Chem. SOC.,61, 1413-17 (1939). (28) Oda, R., and Ogata, Y., J. Soc. Chem. Ind., J a p a n , 44, Suppl. Binding 427 (1941). (29) Pajeau, R., Bull. SOC. chiin. France, 1949, 590-1. (30) Pajeau, R., and Fierens, P., Ibid., pp. 587-9. (31) Rothstein, E., and Saville, R. W., J. Chem. SOC.,1949, 1946-9. (32) Ibid., pp. 1950-4. (33) Ibid., pp. 1954-8. (34) Ibid., pp. 1959-61. (35) Ibid., pp. 1961-8. (36) Schrnorling, L. (to Vniversal Oil Products CO.), U. S. Patent 2,481,158 (Sept. 6, 1949).
Vol. 43, No. 9
(37) Shah, D. N., and Shah, N. M., J. Univ. Bombay, Sect. A, 18, 25-8 (1949). (38) Shishido, K., J. SOC.Chem. Ind., J a p a n , 45, Suppl. Binding 16972 (1942). (39) Shishido, K., and And& S., Ibid., 44, Suppl. Binding 361b-3b (1941). (40) Smyth, G. M., and Moran, A. E. (to American Cyanamid C o . ) , U. S. Patent 2,496,894 (Feb. 7, 1950). (41) Somerville, W. T., and Spoerri, P. E., J. Am. Chcm. SOC.,72, 2185-7 (1950). (42) Ungnade, H. E., and Crandall, E. W., Ibid.. 71, 3009-10 ( 1949). (43) Van Ber'g, C. F. (to Standard Oil Developmcnt C o . ) , U. S. Patent 2,523,168 (Scpt. 19, 1950). (44) Walsh, D. C.. and Schutze, H. G. (to Standard Oil Development Co.), U. S. Patent 2,521,431 (Sept. 5, 1950). (45) Ibid., 2,521,432 (Scpt. 5, 1950). (46) Wilson, S. D., and Shih, S.-C., J . Chinese C h e m Soc., 16, 8.5 91 (1949). (47) Zapp, Robert. Societh in Accomandita, Ital. Patent 433,469 (Aug. 10, 1948). RECEIVED July 3, 1951
HA L OG ENAT10N
__ EARL 1. MCREE and O G D E N R. PIERCE
m@!
PURDUE UNIVERSITY, LAFAYETTE, IND.
A n upward trend i s evident in the production of chlorine and chlorinated organic compounds. M a n y new chlorine plants are in the process of construction or in operation. Research in the Geld has been especially concentrated on the preparation of the gamma isomer of benzene hexachloride and also the preparation of chlorinated olefins and polymers. Hydrocarbon chlorinations have received less emphasis, with the investigations confined mostly to improvement of established techniques. Several reviews have appeared which summarize various chtorination processes. The area of fluorination shows a decline in the study of processes for the synthesis of fluorocarbons and an increase in the preparation of fluorinated olefins and polymers. The reactions of functional group compounds have also been thoroughly investigated. A book embracing this field has been published which will materially aid both the academic researcher and the industrial chemist.
T
HE production of chlorine and chlorinated products is still increasing. This trend is certain t o continue, for in March 1951 chlorine production was 207,106 short tons as contrasted t o 167,091 short tons in March 1950 (98). A comparison of tbe production figures for several important organic materials for the months of January 1950 and January 1951 indicates the increasing utilization of chlorine in the organic chemical industry (99).
cch, lb.
CsHsC1, lb. DDT, lb.
2.4-0,
Ib.
January 1951
January 1950
28,339,500 37,298,506 7,684,104 1 843 750 6 344 '516 905:237
16,776,561 25 790 686 3:364 :448 463,329 2,369,220 326,352
:
CaHaC16, Jb. Gamma uomer
CHLORINATION Several excellent reviews of various chlorination processes have appeared during the past year. Crawford (19) discusses the application of the Deacon process t o the manufacture of phenol and the chlorination of other organic compounds. A review on the preparation, properties, and uses of methylene chloride is given b y Hebberling ( 4 7 ) while Kainer (69) presents a survey of the patent literature dealing with the production of vinyl chloride. PARAFFIN HYDROCARBONS
The chlorination of methane (86) using various light intensities :md reaction pressures in the presence of small amounts of oxygen,
argon, nitrogen, and hydrogen chloride showed t h a t the reaction was inhibited by each of the additives, with the strongest inhibitory effect caused b y oxygen. A study of t h e preparationof methylene chloride (61) from methane, methyl chloride, or a mixture of the two indicated t h a t the best conversion was obtained using a mixture of reactants in a mole ratio of chlorine :methane :methyl chloride of 1: 0.8:0.7. At 380" to 450' C. in a packed tube, a 74% conversion of methylene chloride was obtained. Foster (16)prepared ethyl chloride in a n 80% conversion from chlorine and ethane at 450-500" C. at a contact time of 0.3-0.5 second followed b y passage of the reaction products over a mixture of copper chloride and alumina at 15" C. and 3-second contact time. Randall (81) chlorinated simple aliphatic hydrocarbons using a mixture of the hydrocarbon and tetrachloroethane with chlorine at 400" C . in the presence of cupric chloride. T h e chlorination of propane in this manner yielded: CHCI,, 1%; CClr, 3.5%; C2HCI8, 26%; CzC14, 32.8%; CzHzClr, 31.2%; CBCII, 4%; and C2C18, 1%. The selective substitution of saturated hydrocarbons containing tertiary hydrogen atoms in the presence of other hydrocarbons was accomplished using chlorine in t h e presence of phosphorus pentachloride, ninc chloride, and chlorides of rare earth metals under anhydrous conditions (1). The reaction can also be conducted with nitrosyl chloride or a mixture of chlorine and metal nitrates and nitritea capable of forming nitrosyl chloride b y their interactions (8). Humphrey and Mitchell (66) chlorinated hydrocarbons in the liquid phase using actinic light and employing a technique in which the partially chlorinated mixture was passed over a n adsorbent t o remove color bodies and sludge, and then rechlorinated t o obtain a substantially higher chlorine content. A chlorine content of 60% or higher was obtained with hydrocarbons containing 10 to 16 carbon atoms b y photochemical reaction with
