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ANILINE, PHENYLADIINE, or AMINOBENZEN...

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Originally appearing in Volume V02, Page 48 of the 1911 Encyclopedia Britannica.
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ANILINE, PHENYLADIINE, or AMINOBENZENE, (C6H5NH2) , an organic See also:base first obtained from the destructive See also:distillation of See also:indigo in 1826 by O. Unverdorben (Pogg. See also:Ann., 1826, 8, p. 397), who named it crystalline. In 1834, F. Runge (Pogg. Ann., 1834, 31, P. 65; 32, p. 331) isolated from See also:coal-See also:tar a substance which produced a beautiful See also:blue See also:colour on treatment with chloride of See also:lime; this he named kyanol or cyanol. In 1841, C. J. Fritzsche showed that by treating indigo with See also:caustic potash it yielded an oil, which he named aniline, from the specific name of one of the indigo-yielding See also:plants, Indigofera anil, anil being derived from the See also:Sanskrit nila, dark-blue, and nil¢, the indigo plant.

About the same See also:

time N. N. Zinin found that on reducing See also:nitrobenzene, a base was formed which he named benzidam. A. W. von See also:Hofmann investigated these variously prepared substances, and proved them to be identical, and thenceforth they took their See also:place as one See also:body, under the name aniline or phenylamine. Pure aniline is a basic substance of an oily consistence, colourless, melting at -8° and boiling at 184° C. On exposure to See also:air it absorbs See also:oxygen and resinifies, becoming deep See also:brown in colour; it ignites readily, burning with a large smoky See also:flame. It possesses a somewhat pleasant vinous odour and a burning aromatic See also:taste; it is a highly acrid See also:poison. Aniline is a weak base and forms salts with the See also:mineral acids. Aniline hydrochloride forms large colourless tables, which become greenish on exposure; it is the " aniline See also:salt " of See also:commerce. The sulphate forms beautiful See also:white plates. Although aniline is but feebly basic, it precipitates See also:zinc, See also:aluminium and ferric salts, and on warming expels See also:ammonia from its salts.

Aniline combines directly with alkyl iodides to See also:

form secondary and See also:tertiary See also:amines; boiled with See also:carbon disulphide it gives sulphocarbanilide (See also:diphenyl thio-See also:urea), CS(NHC6H5)2, which may be decomposed into phenyl See also:mustard-oil, C6H5CNS, and triphenyl See also:guanidine, C6H5N: C(NHC6H5)2. Sulphuric See also:acid at 18o° gives sulphanilic acid, See also:NH2 C6H4•SO3H. Anilides, compounds in which the amino See also:group is substituted by an acid See also:radical, are prepared by See also:heating aniline with certain acids; antifebrin or acetanilide is thus obtained from acetic acid and aniline. The oxidation of aniline has been carefully investigated. In alkaline See also:solution azobenzene results, while See also:arsenic acid produces the See also:violet-colouring See also:matter violaniline. Chromic acid converts it into quinone, while See also:chlorates, in the presence of certain metallic salts (especially of See also:vanadium), give aniline See also:black. Hydrochloric acid and See also:potassium chlorate give chloranil. Potassium permanganate in neutral solution oxidizes it to nitro-See also:benzene, in alkaline solution to azobenzene, ammonia and oxalic acid, in acid solution to aniline black. Hypochlorous acid gives See also:para-amino phenol and para-amino diphenylamine (E. Bambergex, Ber., 1898, 31, p. 1522). The See also:great commercial value of aniline is due to the readiness with which it yields, directly or indirectly, valuable dyestuffs.

The See also:

discovery of See also:mauve in 1858 by See also:Sir W. H. See also:Perkin was the first of a See also:series of dyestuffs which are now to be numbered by hundreds. Reference should be made to the articles See also:DYEING, See also:FUCHSINE, See also:SAFRANINE, See also:INDULINES, for more details on this subject. In addition to dyestuffs, it is a starting-product for the manufacture of many drugs, such as See also:antipyrine, antifebrin, &c. Aniline is manufactured by reducing nitrobenzene with See also:iron and hydrochloric acid and See also:steam-distilling the product. The purity of the product depends upon the quality of the benzene from which the nitrobenzene was prepared. In commerce three brands of aniline are distinguished—aniline oil for blue, which is pure aniline; aniline oil for red, a mixture of equimolecular quantities of aniline and ortho- and para-toluidines; and aniline oil for safranine, which contains aniline and ortho-toluidine, and is obtained from the distillate (echappes) of the fuchsine See also:fusion. Monomethyl and dimethyl aniline are colourless liquids prepared by heating aniline, aniline hydro-chloride and methyl See also:alcohol in an See also:autoclave at 220°. They are of great importance in the colour See also:industry. Monomethyl aniline boils at 193—195°; dimethyl aniline at 192°.

End of Article: ANILINE, PHENYLADIINE, or AMINOBENZENE, (C6H5NH2)

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