GB466189A - Manufacture of azo-dyestuffs containing chromium - Google Patents

Abstract

Azo dyes containing chromium are made by heating an azo dye of the general formula <FORM:0466189/IV/1> [wherein R = the residue of a diazo component containing a group capable of binding metal in complex union, R1 = a naphthalene residue and n = 1, 2 or 3, and wherein the NH2 group of R1 is in 1-position and in o-position to the azo group], with a salt of trivalent chromium until on the one hand the complex chromium compound of the azo dye has been formed and on the other hand the NH2 group of R1 has been exchanged for OH. In examples, the following dyes are treated with chromium sulphate: (1) 4-chloro-2-aminophenol-5- sulphonic acid --> 1-naphthylamine-4 : 6-disulpho acid (violet on wool); (2) 5-nitro-2-aminophenol --> 1-naphthylamine-4 : 8-disulphonic acid (greenish blue); (3) 2-aminophenol-4 : 6-disulphonic acid --> (acid) 1-amino-8-naphthol-4-sulphonic acid (bluish-violet); (4) 4-chlor - 5 - nitro - 2 - aminophenol --> 1-naphthylamine - 4 : 8 - disulphonic acid (blue); (5) 5 - nitro - 2 - aminophenol --> 1-naphthylamine-4 : 6-disulphonic acid (blue); (6) 5-nitro-2-aminophenol --> 1-naphthylamine-4-sulphonic acid (blue); (7) 4-chlor-2-aminophenol --> 1 - naphthylamine - 4 : 7 - disulphonic acid (violet); (8) anthranilic acid --> 1-naphthylamine - 4 : 8 - disulphonic acid (red-violet); (9) 1-methoxy-2-amino-4-chlorobenzene --> 1 - naphthylamine - 4 : 8 - disulphonic acid (blue-violet); (10) the dyestuff of (4) is treated with chromium chloride or fluoride; (11) 5-nitro-2-aminophenol --> 1-naphthylamine - 5 : 7 - disulphonic acid is boiled with chromium formate (blue). Examples of dyeing wool, silk, regenerated cellulose, cotton and of colouring a nitro-cellulose lacquer are given. Cellulose esters and ethers are mentioned in the Provisional Specification. Other coupling components specified are 1-naphthylamine-3 : 6-disulphonic acid, 1-naphthylamine - 5 - sulphonic acid, H acid, 1 : 8-diaminonaphthalene - 3 : 6 - disulphonic acid, K acid and 1-naphthylamine-4 : 6 : 8-trisulphonic acid. Chromium salts of acetic, benzene and naphthalene mono-, di- and polysulphonic acids, benzene sulphocarboxylic acids and tetrahydronaphthalene sulphonic acids may also be used. Specifications 210,890 and 247,556, [both in Class 2 (iii)], are referred to. The properties of some of the dyes in which the NH2 group in 1-position is still present are given in the Provisional Specification.