GB422287A - Manufacture of mordant dyestuffs - Google Patents

Abstract

Mordant trisazo dyes are made by coupling H acid first in an acid medium with diazotized aniline or a derivative thereof (R1) and then in an alkaline medium with a diazotized aminoazo compound of the type R3--N = --R2--NH2 in which R2 = a sulphonated benzene nucleus and R3 = a benzene nucleus which contains a hydroxyl group and a carboxyl group in o-position and may also contain further substituents, e.g. methyl or halogen. They yield in chrome printing on cotton green to blue-green shades having good fastness properties, particularly to chlorine. In examples the following dyes are described 3-amino-4-sulphobenzeneazosalicylic acid --> (MgCO2) H acid \sM 4-nitraniline-2-sulphonic acid or 2-nitraniline-4-sulphonic acid; 4 - amino - 2 - sulphobenzene - azo - salicylic acid may also be used. Other components specified are 3-nitraniline-4-sulphonic acid, 4-nitraniline-3-sulphonic acid, p-nitraniline, 4 - chloraniline - 2 - sulphonic acid, sulphanilic or metanilic acid, 4-chloraniline-3-sulphonic acid, 2-chlor-4-nitraniline and 4-chlor-3-nitraniline; instead of salicylic acid there may be used, e.g. cresotinic acid, chloro-salicylic acids and b -resorcylic acid. Specifications 15725/91, 15056/92, [both in Class 2], and 231,885, [Class 2 (iii)], are referred to. The Specification as open to inspection under Sect. 91 also specifies 4-amino-3-sulphobenzene-azosalicylic acid as the aminoazo compound. This subject-matter does not appear in the Specification as accepted.