Formic acid yields acridine, and the higher homologues give derivatives substituted at the meso carbon atom, N N +[[Hcooh-C 6 H 5 /Inc6h5->C6h4 C6h4 Cho Ch N N +Ch 3 000h->C 6 H 5 /IC 6 H 5 --C 6 H 4 < >C6h4 Coch 3 C]](CH3) Acridine may also 1:e obtained by passing the vapour of phenylortho-toluidine through a red-hot tube (C. Graebe, Ber., 1884, 17, p. 1 37 0); by condensing diphenylamine with chloroform, in presence of aluminium chloride (0.
It may be prepared by the fusion of para-toluene sulphonic acid with potash; by the action of nitrous acid on para-toluidine; or by heating para-oxyphenyl acetic acid with lime.
At a temperature of about 300-400° C. the alkyl chloride formed in this reaction attacks the benzene nucleus and replaces hydrogen by an alkyl group or groups, forming primary amines homologous with the original amine; thus methylaniline hydrochloride is converted into paraand ortho-toluidine hydrochloride, and trimethyl phenyl ammonium iodide is converted into mesidine hydriodide.
Jour., 1860, 158, p. 146); by heating aniline for red with nitrobenzene, concentrated hydrochloric acid and iron (Coupier, Ber., 1873, 6, p. 423); or by condensing formaldehyde with aniline and ortho-toluidine and oxidizing the mixture.
Hofmann having previously shown that oxidation of pure aniline alone or of pure toluidine yielded no fuchsine, whilst oxidation of a mixture of aniline and para-toluidine gave rise to the fine red dyestuff para-fuchsine (pararosaniline hydrochloride) CH 3 C 6 H 4 NH 2 +2C 6 H 5 NH 2 +30 = HOC(C 6 H 4 NH 2) 3 +2H20.
Rosenstiehl (Jahres., 1869, p. 693) found also that different rosanilines were obtained according to whether orthoor para-toluidine was oxidized with aniline; and he gave the name rosaniline to the one obtained from aniline and ortho-toluidine, reserving the term pararosaniline for the other.
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 orthoand para-toluidines; and aniline oil for safranine, which contains aniline and ortho-toluidine, and is obtained from the distillate (echappes) of the fuchsine fusion.