A simple cobobator is sbown in Fig. 487 ; it consists mainly of a digester A, made of copper, for high pressures, and connected with a worm B, where all vapours givea off are condensed, and, by openiog the cock C and closing C', are returned to the digester : by closing C and opening C', they can be collected in D. G is a pressure gauge, and V, a safety valve. The cock S ig opened for relieving pressure, or for distillation. The two parts of A, which are nesrly epherical, are firmly bolted together.
A steam pipe P admits steam, when neces sary, to carry off any of the products. When the whole of tbe materials cannot be placed in the digester at ooe time, a tube is fixed to the top, and is supplied with two cadre ; the lower one le firet shut and the upper one is opened, when a supply of the ingredients ocoupiee the space between them ; then by closing the upper cock and opening the lower one, the supply can flow in at any required rate. A pipe and etop-cock, communicating with the digeeter and tube, render the pressure the same in both when the upper cock is closed Poirrier and Chappat prepare alcoholized anilines without the use of iodine or bromine. Hydro chlorate of aniline, or any other salt of this btoe or its homologues, and the alcohol of which it is desired to obtain the radical, are heated in a close vessel under pressure. Alcoholic salts and aniline may be treated in the same way, with the same results. Methyl-alcohol treated with the hydrochlorate of aniline requires 175°-210° (347°-410° F.) for three or four hours, and a longer period will do no harm ; but at 250°-300° (482°-572° F.), one or two hours will suffice. Hydrobro mate, or hydriodate of aniline may be used, and requires only 100°-200° (212°-392° F.). The pro portions are 100-150 parts alcohol to 100 parts aniline salt. The operation produces a salt of the new aniline base, according to the acid ernployed ; this salt is decomposed by soda or potash, and yields a mixture of alkaloids, containing one or more molecules of the alcohol radical. These are separated by fractional distillation. The portion passing over at or about 192° (378° F.) is methyl aniline (supposing methyl-alcohol to have been used), and that at 202° (396° F.) is di-methyl aniline. The products above these points are methyl-toluols, -xylols, &c. ; corresponding to the quality of aniline employed. A.niline, 100 parts ; chloride ammonium, 80-100 parts ; and alcohol,
100-150 parts, heated to 275°-300° (527°-572° F.), for two or four hours, yield a liquid separating into two layers, of which the oily supernatant one is their new alkaloid.
Mono-amyl-aniline. 02115.05H„.NH.—A mixture of aniline and bromide-amyl is allowed to stand for a few days, when crystals of hydrobromate of amyl-aniline separate out ; these are decom posed by potash, wheo the base is obtained free by distillation. It is a colourless, oily liquid, smelling of roses, and boiling at'258° (496° F.) ; it forms, with many acids, crystallizable salts, not easily soluble.
Di-amyl-aniline. 0211,N(C,H,02.—By heating the above at 100° (212° F.) with bromide amyl, crystals of hydrobromate of di-amyl-aniline are formed ; from the,se, the base may be obtained by distilling with potash ; it boils at 275°-280° (527-536° F.), and yields sparingly soluble salts.
C2H, Acetanilick, acetaniline, cr acetyl-phenyl-amine. {0,11,01 N.—This substance may be obtained by the action of acetyl chloride or acetic anhydride upon aniline, or by the distillation of acetate of aniline, hence its occurrence in crude aniline which has been distilled without Hine. According to Greville Williams, it is prepared as follows :—Glacial acetic acid and aniline are mixed in equal proportions, and distilled ; the distillate is returned till it begins to deposit in crystals near the outlet of the still ; when the receiver is changed, the head of the still is kept warm, and the distillation is proceeded with. The yield of acetaniline equals the weigbt of acetic acid employed. It is sparingly soluble in cold water, and crystallizes, from a boiling solution, in shining plates, melting at 106° (223° F.), and boiling at 292° (558° F.). It begins to volatilize at 100° (212° F.), and sublimes st 200° (392° F.).
On adding 80 parts water to a mixture of acetaniline and aceto-toluidine dissolved in four parts glacial acetic acid, the aceto-toluidine precipitates by standing, whilst the acetaniline remains in solution. This may be conveniently employed for the separation of aniline and toluidiue in the examioation of a sample of aniline, when greater accuracy is necessary than can be obtained by fractionizing.