Process for the preparation of acid nitro dyestuffs

摘要

Acid nitro dyestuffs are prepared by treating aminonitrodiphenylaminesulfonic acids with an oxidizing agent in an aqueous medium, the oxidizing agent employed being a manganese-(VI) or manganese-(VII) compound and the reaction being carried out at a pH higher than 5 and at a temperature between 20 DEG and 100 DEG C. The dyestuffs thus obtainable dye even fresh full-grained chrome leather in full shades.