GB359398A - Manufacture of arylated safranines - Google Patents

Abstract

Safranine dyes are arylated by allowing an arylating agent to act on the leuco-compound or by arylating the dye in the presence of a metallic reducing agent, and, if necessary, oxidizing to the dyestuff. Among the dyes which may be obtained are diarylphenosafranines substituted in the aryl nuclei such as the diamino-diarylphenosafranines. The dyestuffs thus obtained dye silk and tanned cotton violet to sky-blue shades and the acid dyestuffs obtained by sulphonating the dyestuffs dye silk and cotton similar shades. In examples, (1) Phenosafranine is dissolved in a mixture of aniline and dry aniline hydrochloride and zinc dust is added. The mixture is then heated, cooled, filtered to remove the zinc dust and a current of air is passed through and the zinc solution is poured into dilute hydrochloric acid giving a precipitate of the dyestuff diphenylphenosafranine. (2) Diethylsafranine is treated in a similar way to example (1), alcohol being added after the cooling to facilitate the removal of the zinc dust, the alcohol being subsequently distilled off prior to the precipitation of the dye. (3) Phenosafranine is dissolved in a mixture of p-toluidine and p-toluidine hydrochloride and zinc dust added. The mixture is boiled and treated as in example (2) to give the ditolylphenosafranine; p-chloraniline, 1 : 2-dimethyl-4-aminobenzene or p-phenetidine may also be used as arylating agents. (4) Phenosafranine is dissolved in a mixture of a -naphthylamine and a -naphthylamine hydrochloride and treated as in example (2) to obtain the dinaphthylated safranine. (5) Phenosafranine is dissolved in molten phenol and after treatment with zinc dust the mixture is heated with p-phenylenediamine and p-phenylene-diamine hydrochloride [or with the corresponding m-compounds], cooled, alcohol added and the mixture filtered; air is blown through, the alcohol is distilled off and the solution is run into ice-cold dilute caustic soda and the dyestuff which is precipitated is filtered off; the dyestuff is extracted with dilute hydrochloric acid and common salt is added to the acid filtrates giving a precipitate of p-p1-diaminodiphenylphenosafranine (or the corresponding m-m1-diamino compound). (7) Phenosafranine is dissolved in phenol and after zinc dust has been added m-toluylenediamine is added and the mixture is worked up as in example (5) to give the m - m1 - diaminoditolylphenosafranine. (8) Phenosafranine is dissolved in o-toluidine and o-toluidine hydrochloride and after zinc dust has been added the mixture is heated, cooled, mixed with alcohol and filtered to separate the zinc dust. The alcohol is distilled off and the filtrate is poured into dilute hydrochloric acid to separate the o-o1-ditolylphenosafranine.