GB403022A - Manufacture of azo-dyestuffs - Google Patents

Abstract

Azo dyes for dyeing leather are made by coupling resorcinol or a carboxylic acid thereof (1 mol.) with 2-nitro-1-amino-4-diazobenzene (2 mols.) or with one molecular proportion of the same diazo compound and one molecular proportion of another diazo or diazoazo compound, or by coupling 2-nitro-1-amino-4-diazobenzene (2 mols.) with 1 mol. of an azo dyestuff: amine--> resoricinol or a carboxylic acid thereof. In examples the following dyestuffs are described: (1)--(2) 2-nitro-1 : 4 - diaminobenzene --> 1:3-dioxybenzene-5- or 6-carboxylic acid\sM 1-amino-4-nitrobenzene-2-sulphonic acid; the second component may be sulphanilic acid or an aminoaphthalene sulphonic acid e.g. 1-amino-4 - nitronaphthalene - 6 - or 7 - sulphonic acid or aminoazo compounds, e.g. 4-aminoazobenzene-4<1>-sulphonic acid or 2-naphthylamine-4 : 8-disulphonic-->a -naphthylamine, (3) 2-nitro-1 : 4-diaminobenzene (1 or 2 mols.)--> resorcinol-->H, K, J or g -acid, (4) 2-nitro-1 : 4-diaminobenzene\sMresorcinol or its 5- or 6-carboxylic acid. Specification 247,187, [Class 2 (iii), Dyes &c.], is referred to.