GB578002A - Improvements relating to the manufacture of hexakisazo dyestuffs - Google Patents

Abstract

Symmetrical hexakisazo dyes suitable for dyeing and staining leather and having the general formula C-->B\sMA-->D\sMA-->B\sMC where A represents a p-diamine of the diphenyl series which may be further substituted, C represents a sulphonated or unsulphonated primary monoarylamine which may be further substituted, e.g. by methyl, methoxy, nitro, hydroxy, chlorine or arylamino (in which the aryl radicle may be substituted), B represents H-acid coupled acid to A and alkaline to C, and D represents N-monoethyl-, N-monomethyl-, N-diethyl-, N-dimethyl-, N-21-chlorophenyl- or N - 21 : 51 - dichlorophenyl - m - aninophenol, or a monosulphonic acid thereof capable of coupling twice, phenol, a -naphthol, resorcinol-4-sulphonic acid, b -resorcylic acid, 1 : 3 : 4-phenylenediaminesulphonic acid, 1-chloro-2 : 4-phenylenediamine, 2 : 4-diaminophenetole, 1 : 5- or 1 : 8-diaminonaphthalene or 1 : 5-dihydroxynaphthalene, or, when C is unsulphonated, one of the aryl m-aminophenols described in Specification 481,070, are made by coupling two molecular proportions of a diazodisazo compound of the formula C --> (alkaline) B (acid) \sM A --> with one molecular proportion of a component D. In examples, the following components are employed: A : benzidine; C : sulphanilic acid, picramic acid, aniline, p-nitraniline, dehydrothiotoluidine-p-sulphonic acid and 41-amino-4-nitrodiphenylamine-21-sulphonic acid. As a further component C is specified naphthionic acid. Specification 373,689 also is referred to.