Aniline salts

A similar experiment can be performed with commercial aniline hydrochloride (or "aniline salt ). 

N-2-cyanoethylaniline has been prepared (accompanied by much of the N,N -bis-2-cyanoethyl compound) by heating aniline, acrylonitrile and acetic acid either in an autoclave, or at refluxing temperature for 10 hours in the presence of various inorganic catalysts. The substance has also been obtained, free of the N,N -bis-2-cyanoethyl compound, from aniline salts and /3-diethylaminopropionitrile. ... 

Combined Erythrina Alkaloids. The sources of the liberated alkaloids (see above) are now known to be, at least in two cases, the sulphur-containing alkaloids erysothiopine and erysothiovine, which are esters of sulphoacetic acid, HOOC. CHj. SOj. OH, identified as the aniline salt, m.p. 187-9° with erj sopine and erysovine respectively. The sources of erysodine and erysonine have not yet been isolated. These combined alkaloids arc believed to be sulphonic esters, of the type HO. OC. CHj. SOj. 0. R, where R is the alkaloidal residue. ... 

Schwarz, n. slop-padded aniline black. -SI, n. aniline oil. -rot, n. aniline red. -salz, n. aniline salt, -schwarz, n. aniline black, -soifoskure, /. anilinesulfonic acid (amino-benzenesulfonic acid), -tinte,/. aniline ink. -vergiftung, /. aniline poisoning. 

Of the primary monoamines, some, such as. aniline, o-toluidine, xylidine, are colourless liquids. Others, such as p-toluidine, pseudo-cumidine and the naphthylamines, are solids. They can be distilled without decomposition and are volatile with steam. In water they are rather sparingly soluble—a 3 per cent solution of aniline can be made. The di- and polyamines are usually solids, not volatile in steam and much more soluble in water than the monoamines. The amines are basic in character, but, as a result of the negative nature of the phenyl-group, the aromatic amines are considerably weaker bases than are the aliphatic amines. Consequently aqueous solutions of the (stoicheio-metrically) neutral aniline salts are acid to litmus because of the hydrolysis which they undergo. For the same reason a small amount of the free base can be extracted with ether from an aqueous solution of an aniline salt. (Test with a solution of hydrogen chloride in ether or, after evaporation of the ether, by the reaction with bleaching powder.)... 

A sample of the reaction mixture should not become turbid when sodium acetate solution is added. But if now a few drops of a solution of an aniline salt are poured in, there is precipitated yellow diazoaminobenzene, which can be re-dissolved with concentrated hydrochloric acid after a few small pieces of ice have been added. Further, when a few particles of j8-naphthol or of R-acid are dissolved in a small excess of 2 A-sodium hydroxide solution and a sample of the diazo-solution is added, an intense red colour is produced. The development of this colour, which results from coupling , is an infallible test for a diazonium salt, and hence also for the corresponding primary aromatic amine. 

Compounds of this type are soon reconverted by adds into dia-zonium- and amine-salt. In the case of the diaryltriazenes this reconversion is already caused by a quite feebly acid reaction, e.g. that of aniline salts in the presence of excess of base but under these conditions the diazonium salt can combine with the amine present in excess to form an azo-dye (Rosenhauer). The equation... 

Aniline black is also an important fast dye for cotton and is produced on the fibre at a high temperature (by steaming ) from an aniline salt (hydrochloride) and an oxidising agent. It is not probable that the two kinds of this dye which are known have the same constitution, for they have different degrees of stability towards acid technical aniline black probably contains phenazine ring systems (Bucherer, Green). 

The reaction with aniline salts was explained simultaneously by Zincke and by Dieckmann in 1905. The furane ring undergoes amino-lytic cleavage and then the anil is formed from the aldehyde. 

Of the various published methods of preparing phenylurea, such as treatment of aniline salts with potassium cyanate in water solution,1 heating aniline with urea,2 with cyanic acid,3 or with cyanogen chloride,4 and the interaction of phenyl isocyanate or phenylcarbamine chloride with ammonia,5 the only ones to be considered as practical methods for preparation are the first two. The first suffers from the disadvantage that potassium cyanate is not easily prepared in the laboratory and rapidly undergoes spontaneous decomposition in storage while by the action of urea on aniline alone, carbanilide is formed in rather larger proportion than phenylurea. 

The procedure described here is based on a method outlined in U. S. patent 2,444,536.2 N-Phenylmaleimide has also been prepared by the dry distillation of the aniline salt of malic acid, 4 by treating the aniline salt of malic acid with phosphorus pent-oxide,5 and by treating maleanilic acid with phosphorus trichloride or with phosphorus pentoxide.5 Ring-substituted N-phenylmaleimides, viz., N-(/>-methoxyphenyl)-, N-(p-ethoxy-phenyl)-, and N-(/>-nitrophenyl)maleimide, have been prepared by treatment of the appropriate maleanilic acids with acetic anhydride and fused potassium acetate.7... 

Owing to the highly explosive nature of the diazobenzene nitrate, its preparation should never be undertaken except the compound is wanted for research or some special purpose. 20 gms. of aniline are placed in a beaker, well cooled, and boiled-out nitric acid, previously diluted with half its volume of water, oarefully added till the mixture sets to a thick crystalline paste—aniline nitrate. The crystalline mass is filtered off at the pump, and washed with a little cold water. 5 gms. of the moist salt are finely powdered and placed in a small flask with enough water just to cover the substance. The flask is now well cooled in ice-water, and nitrous fumes (for preparation, see p. 513) are led in with frequent agitation until all the aniline nitrate has disappeared. At no time must the temperature of the flask rise above 10°. Should there not be sufficient water to keep all the diazobenzene nitrate formed in solution, its crystalline form will easily enable it to be distinguished from the aniline salt. When the reaction is finished the contents of the flask are poured into 3 times their volume of absolute alcohol, and ether is added to this mixture as long as crystals separate. If too much water has been added to the aniline nitrate from the beginning, a thick aqueous solution of diazobenzene nitrate separates out in place of the crystals. If this occurs, the ether-alcohol is decanted off, and the residue redissolved in absolute alcohol, and reprecipitated with ether. On no account must... 

The solution of the diazonium salt is mixed with an aniline salt and excess of sodium acetate, or the solution is shaken up with a few drops of aniline. In either case a yellow crystalline precipitate of diazoamino-benzene is obtained. 

The problems associated with the separation of phosphate esters are the tendency of the spots to diffuse difficulty of reproducing RF values variability of RF values with complexity of the mixture being resolved and distance of solvent travel proper purification and equilibration of the filter paper effect of inorganic ions in natural mixtures and the choice of suitable solvent mixtures for desired separations. The problem of detecting the separated spots is somewhat simpler. In addition to methods applicable to the detection of reducing sugars (e.g., use of aniline salts fructose esters are detected by naphthoresorcinol-acid), methods depending on phosphomolybdate formation are most commonly used. Hanes and Isher-... 

The numerous experiments which led to the formation of dyes at the anode, when aniline, toluidine, methylaniline,. diphenylamine, nethyldiphenylamine and naphthylamine or their salts were electrolyzed, have, however, not been scientifically investigated and, hence, still remain unsolved. The same holds true of Goppelsroder investigations concerning the oxidation of phenol and anthraquinone. The most important discovery is the fact that aniline salts smoothly yield aniline black at the anode the naphthylamine salts give naphtliylamine-violet.1... 

Other known catalysts for cyanoethylation of aromatic amines include acetic acid,5 6 acetic acid-cuprous chloride mixtures,7 8 aniline salts,9 and choline.10 3-Anilinopropionitriles may also be prepared by an exchange reaction between the aniline hydrochloride and diethylaminopropionitrile.2 4... 

Aniline does not give water-stable salts with weak acids like acetic acid. Some aromatic amines do give crystalline acetates with acetic acid, but these are decomposed by water with separation of the free base. This property is utilized industrially in the isolation of m-xylidine from a mixture containing its isomers. Hence, free aniline separates out of an aqueous solution of an aniline salt with a mineral acid if the mineral acid anion is replaced by the acetate ion, for example, by the addition of sodium acetate in sufficient concentration. 

Selective demethylotion. Alkyl methyl phosphates undergo demethylation when treated with dimethyl sulfide or ethanethiol and methanesulfonic acid (equation I). The products are isolated as the aniline salts. 

The formation of Schiff bases by the reaction of ketones with amines is more difficult. Acetophenone and other aryl alkyl ketones which are slow to react under the usual conditions will combine with aromatic amines at 160-180° in the presence of a zinc chloride-aniline salt. In another procedure, 2-acetylthiophene and aniline are condensed in boiling toluene with the aid of a water separator. ... 

Commercial processes for obtaining the N-alkylated anilines are based on the reaction of aniline salts with alcohol in an autoclave at about 200°. A laboratory adaptation of this application of an alcohol as the alkylating... 

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