GB608115A - Manufacture of disazo-dyestuffs containing copper in complex union - Google Patents

Abstract

Disazo dyestuffs containing copper in complex union are manufactured by coupling one molecular proportion of a tetrazotised unsulphonated diaminodiphenyl, containing an alkoxy group in o-position to each diazo group, in an alkaline medium with two molecular proportions of the same or one of each of two different monohydroxynaphthalene mono- or di-sulphonic acids free from amino, alkoxy or carboxyl groups (but excluding 2-naphthol-6-sulphonic acid in the case of dyestuffs containing only two sulphonic acid groups), and heating the product with an ammoniacal solution of copper sulphate until the alkoxy groups have been dealkylated. The products dye vegetable fibres in blue shades from an alkaline or neutral bath by the methods usual for direct dyestuffs. In examples: (1) 1 mol. of dianisidine is tetrazotized and coupled with 2 mols. of 2-naphthol-3 : 6-disulphonic acid and the product is boiled with aqueous ammonia with the addition of copper sulphate solution; the coupling component may be replaced by 2-naphthol-4-sulphonic acid, 1-napthol-4 : 8-disulphonic acid or 8-chloro-1-naphthol-3 : 6-disulphonic acid; (2) 1 mol. of dianisidine is tetrazotized and coupled with a mol. each of 2-naphthol-3 : 6-disulphonic acid and 2-naphthol-4-sulphonic acid and the product is coppered as in (1); the first coupling component may be replaced by 8-chloro-1-naphthol-3 : 6-disulphonic acid, 1-naphthol-3 : 8-disulphonic acid or 1-naphthol-4- or 5-sulphonic acid, or the second by 1-naphthol-4- or 5-sulphonic acid; (3) cotton is dyed reddish-blue with the first duestuff of (1) from a bath containing Glauber salt. Additional coupling components specified are 2-naphthol-6-sulphonic acid (subject to the excluding note above) and 2-naphthol-6 : 8-disulphonic acid.