SAFRANINE  , in

chemistry, the azonium compounds of symmetrical diamino-phenazine and containing the ring system annexed:- C(ANY) or \ Cl 1~ C1 I2 They are obtained by the joint oxidation of one molecule of a paradiamine with two molecules of a primary amine; by the condensation of para-aminoazo compounds with primary amines (0 . Witt, Ber., 1877, 10, p . 874), and by the action of para-nitrosodialkylanilines with secondary bases such as diphenylmetaphenylenediamine . They are crystalline solids showing a characteristic green metallic lustre; they are readily soluble in water and dye red or violet . They are strong bases and form stable monacid salts . Their alcoholic solution shows a yellow-red fluorescence . Phenosafranine is not very stable in the free state; its chloride forms green plates . It can be readily diazotized, and the diazonium salt when boiled with alcohol yields aposafranine or benzene induline, C,BH,zN, . F . Kehrmann showed that aposafranine could be diazotized in the presence of cold concentrated sulphuric acid, and the diazonium salt on boiling with alcohol yielded phenylphenazonium salts . Aposafranone, C,H12N20, is formed by heating aposafranine with concentrated hydrochloric acid . These three compounds are perhaps to be represented as ortho- or as paraquinones (see papers by F .

Kehrmann, O .

Fischer and E . Hepp; R . Nietzki and others, Ber., 1895 et seq.) . The " safranine " of commerce is a tolusafranine . The first aniline dye-stuff to be prepared on a manufacturing scale was mauveine, C ,H2,N,C1, which was obtained by Sir W . H . Perkin by heating crude aniline with potassium bichromate and sulphuric acid . It is a N-phenylsafranine (see INDULINES) .