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gel, sol, hydrosol, jelly, emulsion, coagulation, etc., should be consulted, and many papers, especially those listed in Ch,emicaZ Abstracts under General and Physical Chemistry, and Biological Chemistry, contain colloid chemical work. Thus 57’. E. 8. Turner’s book on “Molecular Association” (p. 99) has the following pertinent stktement:
Vol. 14, No. 9
The formula of a substance shall be recognized as a function of the physical conditions under which it exists, so that the formula for elements is X n , for compounds ( X Y ) n , where n is to be specified according to the conditions. Although we are far from realizing how n varies for most substances, the adoption of such formulas would bring home clearly the‘fact that both the physical and the chemical behavior of the substance may be closely dependent on the value of 12.
T h e Chemistry of Intermediates By M. L. Crossley CALCOCHEMICAL C o . , BOUND BROOK,N. J.
HE PERIOD under review is particularly marked by toluene and naphthalene, and vanadium pentoxide has been the successful application of sound physicochemical chosen, in most cases, as the most suitable for the purpose. It principles to the solution of the complex problems in- has been shown that a high-grade benzoic acid can be obtained volved in the manufacture of organic compounds. More than by fusing benzene sodium sulfonate with sodium cyanide.4 ever before, it has been demonstrated that physics and chemis- The practical application of fhis process is; however, questry are indissolubly linked and that in this union is tionable. Benzoic acid has also been made by a great potential power for use in the service of modification of the Friedel and Cra€ts reactions -passing phosgene into benzene and carbon humanity. Much of the progress made in the chemistry of intermediates during the past bisulfide a t a low temperature, then adding few years has been due to the combined aluminium chloride and subsequently hyefforts of organic and physical chemists. drolyzing to benzoic acid and recovering The catalyst has been the key to unlock the carbon bisulfide. If carbon bisulfide many molecules and thus permit reacis not used, benzophenone is the main tions not otherwise realizable. Our knowlproduct of the reaction. The benzopheedge of surface phenomena is rapidly none is converted into benzoic acid by leading to a better understanding of the fusing with caustic. This process for benzoic acid is interesting but it does not mechanism of chemical reactions. I n one other respect the past few years seem capable of ultimately competing in the chemistry of intermediates have with the catalytic process. It should be of been noteworthy, that is, in the evergreat importance as a process for the manincreasing evidence of the interdepenufacture of benzophenone when this product is required as a dye intermediate. dence of dye intermediates and pharmaceuIntensive and well-executed researches on tical products. Salicylic acid has given us an excellent nontoxic local anesthetic-salicyl the catalytic air oxidation of benzene and naphthalene have resulted in processes for the alcohol, and some complex carbamide of the naphthalene series involving H acid is probably the future manufacture of maleice and fumaric acids from remedy for sleeping sickness. Although the constiM. L. CROSSLSY benzene and phthalic acid7 from naphthalene. It is difficult a t this time to correctly evaluate the contritution of “Bayer 205”’ is not disclosed, it is thought to be one of the several carbamides or closely related sub- bution that these diwoveries will make to the economic stances on which so much research activity centered in development of our time, but it is safe to say that they appear to be the most important contribution to the progress of the Germany during the years 1914-1916. Progress has been diversified. In a few instances the synthetic organic chemical industry made during this period. results have led to the production and utilization of new com- With cheap maleic and fumaric acids available new industries pounds, while in the majority of cases the achievements have will arise. Fumaric acid may yet be the initial raw material for not been epoch-making but rather the necessary improve- the synthesis of indigo.8 Cheap phthalic anhydride makes ments to make already existing processes adaptable to modern possible synthetic anthraquinone, and this means unhampered economic conditions or the development of new processes progress in the development of the anthraquinone dyes, particularly indanthrene and other vat dyes. Phthalic anhydride for old products. will become of increasing importance in the manufacture of inCARBOXYLIC ACIDS termediates. A new intermediateQfor azo dyes is prepared Both catalytic and electrolytic processes have been de- by combining phthalic anhydride with 1,7-aminonaphthol. veloped for the manufacture of carboxylic acids. At the SULFONIC ACIDS present time the catalytic processes appear to be more ecoSulfonation has. received considerable attention of late. nomical and practical. Acetic acid2 is obtained by the catalytic oxidation of acetaldehyde and benzoic acid3 by both A continuous process,lo introducing the sulfuric acid and the 4 Chem Met. Eng , 24 (1921), 638, 697. catalytic and electrolytic oxidation of toluene. Many sub5 THIS JOURNAL, 14 (1922), 406. stances have been tried as catalysts in the air oxidation of U S Patents 1,318,632, 1,318,633, 1,377,534.
T
6
“Annual Reports of the Progress of Chemistry for 1921,” Chem. SOC., 18 (1921), 187. * Ger. Patent 299,782. J. SOC.Chem. Ind , 40 (1921), 307R. 1
7 8
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THISJOURNAL, 14 (1922), 120; Brit. Patents 164,785, 145,071. J . A m . C h e n Sac., 44 (1922), 216. Brit. Patent 145,057. Brit. Patent 147,967.
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T H E JOURNAL OF INDUXTRIAL A N D ENGINEERING CHEMISTRY
hydrocarbon through atomizers into the upper portion of a steam-jacketed tower provided with a condenser, permits the reacting mass to flow down the tower over bafffed plates, thus completing the reaction. The product is drawn off at the bottom of the tower and any condensed hydrocarbon returned to the charging apparatus. It has been found that certain catalysts enhance sulfonation and in some cases affect the orientation of the sulfonic group.ll Benzoic acid, when sulfonated in the presence of a small quantity of iodine, gives the o-sulfonic acid.12 A small quantity of anhydrous sodium sulfate and vanadium pentoxide used as a catalyst in the mlfonation of benzene doubles the amount of benzene sulfonated per minute.13 By the use of a small quantity of iodine' 1 as a catalyst certain sulfonations are made possible with weaker sulfuric acid than would otherwise be required. The time of sulfonation is also shortened. This catalyst is particularly suitable for sulfonations of benzene compounds containing substituents such as OH, NH2, COOH or halogen, but works with difficulty or not a t all with compounds of the benzene series containing SOsH or NO2 groups. Other catalystsl5 have been studied and in certain cases found to have marked influence on both the quality and the yield of the sulfonated product. Certain definite progress has been made in bringing about difficult sulfonations. The problem of finding a satisfactory method for the preparation of chlorobenzene-disulfonic acid has been solved by sulfonating p-chlorobenzenesulfonyl chloride16 with monohydrate a t 160" to 180" C. The yield is said to be quantitative. The resulting product is 4-chlorobenzene-1,3-disulfonic acid. Again it has been shown definitely that the product obtained by the sulfonation of metanilic acid is the 3,6-disulfonic acid17 of aniline. Sulfanilic acid when heated with a mixture of sulfuric acid and phosphoric oxide at 180" C. for eight hours gives aniline2,4,6-trisulfonic acid. The yield is poor and the process needs further refinement.l* ALDEHYDES
Comiderable progress has been made in the preparation of aldehydes on an industrial scale. Acetaldehyde has been made in large quantities from acetylene. Where cheap power is available this should be a practical process for the manufacture of ncetaldehyde and its derivatives, particularly acetic acid. Cheap acetic acid is indispensable to the development of the cellulose acetate industry. Benzaldehyde is obtained by catalytic air oxidation1gof toluene and salicylaldehyde20 by oxidizing o-cresol in the vapor phase with air or a suitable gas containing oxygen in the presence of a metallic oxide which serves as a catalyst. Electrolytic processes have also been developed for benzaldehyde but it is still uncertain whether they are practical. A very interesting catalytic process for hydroxyaldehydes consists in treating phenol or derivatives of phenol with formaldehyde in the presence of nitroso compounds. Vanillin is prepared by treating guaiacolz1 with formaldehyde in the presence of p-nitrosodimethylaniline. AMINES The progress in catalytic reduction of cyclic nitro compounds to the corresponding amines has been slow and un11
J Chem. Soc., 117 (19201, 1405.
I b i d . , 117 (1920), 1405. THISJOURNAL, 12 (1920), 968. 14 J SOC.Chem. Znd., 4 0 (1921), 40A, 715A 16 Private communication. 16 Ger. Patent 260,563. 17 Rec. ~ Y W . cham, 39 (1920), 499. 18 Ibzd., 39 (1920), 194. 18 Brit. Patent 165,076. 20 U. S. Patent 1,380,277. 2 1 Brit. Patent 164,715. 12
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certain. Many processes have been developed but it appears that they are still in an experimental stage. An almost quantitative yield of aniline22 is claimed to be obtained by passing a mixture of nitrobenzene vapor and hydrogen or water gas or an alcohol capable of giving hydrogen on dehydrogenation over heated copper oxide. Several catalysts have been studied. Some are effective in the liquid phase and others in the vapor phase. Certain compounds of the type R-CH=NRZ3 are reduced to secondary amines by passing hydrogen in the liquid containing a suspension of finely divided nickel. The researches on catalytic reduction continue with unrelenting vigor. Some progress has also been reported in the reduction of certain substituted nitro compounds with different reducing agents. p-Nitrophenol, 2,4-dinitrophenol, and the o- and p-nitrobenzoic acids have been reduced to the corresponding amines by iron and sulfurous acid.24 Certain other nitro compounds have been reduced to the corresponding hydroxylamines or amines in an aqueous emulsion with alkali sulfides. Nitrobenzene gives by this method a yield of 72 to 74 per cent of practically pure crystalline P-phenylhydroxylamine. Mononitroaniline and p-nitroaniline are reduced to the corresponding diamines.25 The catalytic alkylation of amines has received some attention. A mixture of monomethylaniline and dimethylaniline has been obtained by passing a mixture of aniline and methanol over aluminium oxide or silica gel. Methylxylidines and naphthylamines have also been prepared by similar processe4, that is, by passing a mixture of alcohol and amine vapors over alumina at 360" to 380" C.26 The butylanilines have been prepared and are -now available as intermediates. Likewise, N-methylvinylaniline27 has been prepared and studied. The unsaturated group is hydrolyzed later to acetaldehyde. A catalytic process for diethylanilinezs has been described, which consists of heating aniline hydrochloride, ethyl alcohol and a mixture of sodium bromide, cupric chloride, and calcium chloride for several hours in an autoclave. Alkyl-rn-phenylenediamineszgare prepared by heating primary or secondary alkylamines or their salts with resorcinol. The reaction appears to be accelerated by sulfurous acid. Improved processes have appeared for the preparation of neutral alkyl esters of sulfuric acid to be used as alkylating agents. Diethyl sulfate30 is made by passing an excess of ethylene or mixtures of ethylene and an inert gas into monohydrate or into a sulfuric acid solution of ethyl hydrogen sulfate at about 75" C., and subsequently either extracting the diethyl sulfate with ligroin or benzene or using the reaction product directly for alkylation. A process has also been patented to make dialkyl sulfates by treating acyclic alcohols with so3 in the presence of dehydrating agents such as phosphorus pentoxide, anhydrous sodium sulfate or anhydrous copper sulfate.31 Certain new amino compounds have been proposed as intermediates. m-4-Xylidine-5-sulfonic acid32 and 6-nitrom - 4 - x ~ l i d i n egive, ~ ~ when diazotized and coupled with certain phenols, naphthols, and their derivatives, azo dyes and lakes superior in fastness and brilliancy in hue to similar Bull. soc chim , '29 (1921),217, Brit. Patent 166,283. Comfit. r e n d , 172 (1921), 280, Bull $06. chzm , 29 (1921), 106. 2 4 Brit Patent 165,838. 26 J. Chem Soc , 119 (l921), 765. Comfit. r e n d , 171 (1920), 1154. 27 Ber., 62 (1919), 2261 28 THISJOURNAL, 12 (1920), 636. 29 Brit Patent, 168,689. 3 0 Brit Patent 157,578, J Soc Chem I n d , 40 (1921), l95A 31 Brit Patent 143 260. 3 2 Brit Patent 164,053. 3 s J. Chem S o c , 119 (1921), 717.
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dyes made from xylidine. Cyclic nitroamines**are obtained by boiling chloronitrocylic compounds with ammonium acetate. 2,4-Dinitroaniline is obtained by saturating acetic acid of 80 to 90 per cent strength with dry ammonia gas and then adding slowly 1,2,4-~hlorodinitrobenzene, maintaining the temperature of the reaction between 124" and 130" C. Ammonia is passed into the reacting mixture during the r e action to replenish the ammonium acetate as fast as it is used up. Methyl-@-naphthylamine-6-sulfonicacid36 is produced by heating a mixture of Schaeffer salt, methylamine hydrochloride, and caustic soda solution in a rotating autoclave at 180Oto 200' C. for six to seven hours. A yield of 72 to 74 per cent of the sodium salt of the acid is obtained. This promises to be an important initial product for the preparation of the N-substituted derivatives of @-naphthylamine. Acyldiaminodiarylsulfones86 appear t o be useful intermediates. They are prepared by the acetylation of diaminodiarylsulfones synthesized from the corresponding chlorodinitro compounds and alkylsulfinic acids. Methyl-@-naphthylamine has been condensed with p-toluenesulfonyl chloride to give the corresponding toluene-p-sulfonylmethyl-0-naphthyl~lmine,~' which serves as the initial product for the preparation of a new group of intermediates. N-Arylthiomorp h o l i n e ~are ~ ~obtained by condensing primary cyclic amines having a free ortho position to the NH2 group with @, p'-dichlorodiethylsulfide. They are proposed as dye intermediates. When @-naphthylamine is sulfonated with 94 per cent sulfuric acid a mixture of 35 per cent of the 8-sulfonic acid and 65 per cent of the 5-sulfonic acid, together with small quantities of the six and seven isomers, is obtained.3g The mixture of isomeric sulfonic acids is converted into the corresponding sodium salts and these are separated by crystallizing them from sulfuric acid solution. ANTHRAQUINONE AND ITS DERIVATIVES
Vol. 14, No. 9
an inert high-boiling solvent like nitrobenzene. Arylaminoanthraquinones47 are formed by treating an aminoanthraquinone containing one or more NH2 groups with metal amides and in the presence of primary cyclic amines such as aniline or its homologs. BENZOPHENONE I n view of the fact that benzophenone has been prepared from benzene's and that such a process should give a relatively cheap product it is important to know that very vivid scarlet dyes, fast to light, fulling and washing are produced from 4,4'-diaminobenzophenone49 by tetrazotizing and coupling the resulting tetrazotized product with @-naphthols and @-naphtholsulfonicacids.
PARA-CYMENE A determined effort is being made to utilize p-cymenea waste product from the sulfite-cellulose industry. It is nitrated and reduced in alkaline medium to hydrazocymene,60 which is then rearranged to the corresponding 3,3'-dimethyl6,6'-diisopropylbenzidine. 5-Nitro-2-amino-l-methyl-4-isopropylbenzene, 5-amino-2-acetylamino-l-methyl-4-isopropylbenzene, and 2,6-diamino-l-methyl-4-isopropylbenzene have been prepared from cymene and proposed for intermediates for azo dyes.61 Aminocymene has been proposed as an intermediate for azo, sulfur, and indigoid dyes.62 HYDRAZINES Certain cyclic hydrazines have been prepared and converted into the corresponding pyrazolones. The process for p-nitrophenylhydraziness has been improved by the substitution of ammonium sulfite for sodium sulfite in the reduction. By condensing phenylhydrazine-m-sulfonicacid54 with dioxytartaric acid a pyrazolone is obtained which dyes wool and silk a yellower hue than ordinary tartrazine. The 1,4- and 1,5-naphthyfhydrazinesulfonic acids63 give pyrazolones which dye wool and silk red and brownish red colors.
Particular activity has centered on anthraquinone and its derivatives. Anthracene is now satisfactorily oxidized to anthraquinone by catalytic40 and e l e ~ t r o l y t i cmethods. ~~ HYDRONAPHTHALENES Synthetic anthraquinone is a reality and the future of the Marked progress has been made recently in the producanthraquinone dyes is assured. tion and utilization of hydrogenated naphthalene.56 It is Many new derivatives of anthraquinone have been prepared. found to be an excellent solvent particularly useful in the @-aminoanthraquinone is chlorinated to 3-chloro-2-aminopurification of naphthalenes' when a very pure product is anthraquinoner? in an inert organic solvent and l-hydroxy- required. Several derivatives of di- and tetrahydronaphanthraquinone dissolved in nitrobenzene is chlorinated in thalenes have been prepared and used as intermediates for the presence of a small quantity of iodine and a sufficient azo dyes. amount of solid sodium carbonate to neutralize liberated It is not possible a t the present time to say just what adhydrochloric acid to l-chloro-4-hydroxyanthraquinone.43 vantages the hydrogenated derivatives of naphthalene posIt has been shown that the dibromoanthraquinone used by sess as intermediates. The difficulties in nitrating the Graeber and Libermann in the synthesis of alizarin was not hydrogenated naphthalenes appear to have been overcome the l12-dibromoproduct as they thought, but the 2,3-is0mer.~~ and both nitro58 and amino68 compounds are now made. @-Halogenderivatives of anthraquinone46 result when a-halo- Tetrahydro-P-naphthol160difficult to obtain by hydrogenagen anthraquinones are heated with sulfuric acid to 200" C. tion of P-naphthol, is now obtained by sulfonating tetraThis is an interesting case of intramolecular isomerization and hydronaphthalene and subsequently fusing the sodium or necessitates research to establish the mechanism by which potassium salt of the resulting sulfonic acid. it and similar reactions come about. Alkylaminoanthraquinones46 are produced by the action of alkyl sulfates on aminoanthraquinone in the presence of a mild alkali and in Brit. Patent 169,688. 86 J . SOC.Chem. I n d . , 41 (1922), 1T. 80 Ibid., 41 (1922), 3 ". 87 J . SOC.Chem. I n d . , 41 (1922), 3T. 88 Brit. Patent 133,108. Giorn. chim. ind. a991., S (1921),97. (0 U. S. Patent 1,355,098. 4 1 U. S. Patent 1,397,562. 42 Brit. Patent 172,682. 48 Brit. Patent 172,682. '4 Annual Reports, J . SOC.Chem. Ind., 6 (1921),95. 46 Brit. Patent 169,732. Brit. Patent 147,964. 84
48
U. S. Patent 1,394,851. THISJOURNAG, 14 (1922),406.
4B
Ger. Patents 338,683,333,077,330,824.
47
U. S. Patents 1,314,924,1,314,923;B e y . , 53 (1920), 78. 61 U. S. Patents 1,314,925,1,314,926,1,314,924,1,314,921,1,314,922. 6 2 U. S. Patents 1,314,928, 1,314,929.
60
J . Chem. SOC.,121 (1922), 715. J . SOC.Chem. Ind., 40 (1921), 176T. Ibid., 40 (1921), 176". 6s J . Chem. SOC., 117 (1920),241, 1574; Ger. Patents 299,603,324,861, 305,104, 298,541, 298,553, 301,275, 336,615, 299,014, 326,486, 337,157, 316,218,335,477,335,602. b7 Ger. Patent 317,634. P British Patent 148,923. 69 Brit. Patent 170,867. $0 Brit. Patent 148,408. 68 54 66
