Process for the preparation of sulpho-free triphenyl-methane dyestuffs

Abstract

Process for the preparation of sulpho-free triphenylmethane dyestuffs of the formula ##STR1## in which R.sup.1 -R.sup.3 denote hydrogen, C.sub.1 -C.sub.6 -alkyl, preferably methyl, or halogen, preferably chlorine, Y denotes hydrogen or NX.sup.5 X.sup.6, X.sup.1 -X.sup.6 denote hydrogen, C.sub.1 -C.sub.6 -alkyl, preferably methyl, ethyl, benzyl or phenyl and Z.sup.- denotes an anion by oxidation of their leuco products with manganese dioxide, characterized in that, after the oxidation is completed, manganese hydroxide or manganese carbonate and the carbinol base of the dyestuff are formed by the addition of hydroxide or carbonate, during or after which the carbinol base is taken up in a water-immiscible solvent, separated off from the manganese hydroxide or manganese carbonate and from the water phase, the solution is mixed with the acid HZ which may have been mixed with water, the solvent is either distilled off before the mixing or separated or distilled off after the mixing, and the dyestuff is isolated as a solution or in solid form after evaporation or crystallization.

Dependencies are inferred from the claim text.