GB462719A - Manufacture of water-soluble azo-dyestuffs - Google Patents

Abstract

Azo dyes soluble in water are manufactured by coupling simultaneously or successively 1 mol. of a dihydroxy or trihydroxy compound of the benzene series, capable of coupling twice, e.g. pyrocatechol, resorcinol, pyrogallol, phloroglucinol or their derivatives capable of coupling twice, with 2 mols. of a diazo-compound or 1 mol. of one diazo- or diazoazo-compound and 1 mol. of another, at least one of these diazo-compounds being a 5-diazoacenaphthene and the components being such that the dyestuff produced contains at least one sulphonic acid group. The products are suitable for dyeing leather. Examples describe the production of the following dyestuffs: (1) 5-aminoacenaphthene --> 1 : 3-dihydroxybenzene-5-sulphonic acid \sM 2-nitraniline-4-sulphonic acid; (2) 5 - aminoacenaphthene - 8 - sulphonic acid --> resorcinol \sM sulphanilic acid; (3) 5-aminoacenaphthene - 8 - sulphonic acid --> phloroglucinol \sM 4-amino-3 : 2<1>-dimethyl-1 : 1<1>-azobenzene - 5 : 4<1> - disulphonic acid. A table is given of further dyestuffs, the following additional components being specified: first diazo-components: 5-aminoacenaphthene-3-, 4- and 7-sulphonic acids; second diazo-components: 4 - nitro - 1 : 3 - diaminobenzene, the dyestuff picramic acid --> 1 : 8-aminonaphthol-3 : 6-disulphonic acid, the dyestuff benzidine --> salicylic acid, 5-aminoacenaphthene-7- and 8-sulphonic acids, 3-amino-5-sulpho-6-hydroxybenzene-1-carboxylic acid, 2-naphthylamine-6 : 8-disulphonic acid, 4-aminodiphenylamine-2-sulphonic acid, 4-nitraniline-2-sulphonic acid, aniline - 2 : 4 - disulphonic acid, the dyestuff 6 - chloro - 2 - toluidine - 4 - sulphonic acid --> m-toluidine and the dyestuff sulphanilic acid --> 1-naphthylamine-6-sulphonic acid; coupling components: 1 : 3-dihydroxybenzene-4- and 5-carboxylic acids and pyrocatechol. Specifications 251,140, [Class 2 (iii)], 437,657, 447,775, and 447,814 are referred to. The Provisional Specification comprises in general the coupling of 1 mol. of a component of the benzene or naphthalene series, capable of coupling at least twice, with at least 2 mols. of a diazo-compound or at least 1 mol. of one diazo-compound and at least 1 mol. of another, at least one of these compounds being a 5-diazoacenaphthene and the finished dyestuff containing at least one sulphonic acid group. An additional example describes the production of the dyestuff 5-aminoacenaphthene-7-sulphonic acid (2 mols.) \sQ resorcinol (1 mol.) \sM 2-nitraniline-4-sulphonic acid (1 mol.). It is stated that the dyestuffs may be oxidized or may be treated with an agent yielding a metal, and reference is made to the chromium compound of the dyestuff 5-aminoacenaphthene-3-sulphonic acid --> resorcinol \sM 3-amino-5-sulpho-2-hydroxybenzene-1-carboxylic acid.