GB331839A - Manufacture of new azo dyes - Google Patents

Abstract

331,839. Imperial Chemical Industries, Ltd., Brightman, R., and Wellacott, W. L. B. March 5, 1929. Disazo dyes suitable for dyeing regenerated cellulose rayon in even shades are made (1) by tetrazotizing 3 : 3<1>-diaminodiphenylurea or sub. stitution products thereof other than hydroxy, carboxy, or sulphonic derivatives and coupling with a sulphonic or carboxylic acid of a phenol or a naphthol (1 mol.) and a 1: 8-dioxynaphthalene sulphonic acid or 2 : 8 : 6-acid or an N-substituted derivative of the latter (1 mol.); (2) by treating with phosgene equimolecular proportions of the dyestuffs obtained by (a) coupling diazotized m-nitraniline or m-aminoacetaniline or substitution products thereof other than hydroxy, carboxy, and sulphonic derivatives, with a carboxylic or sulphonic acid of a phenol or a naphthol and reducing or hydrolyzing, (b) coupling the same diazo components as in (a) with a 1 : 8- dioxynaphthalene sulphonic acid or 2 : 8 : 6-acid or an N-substituted derivative of the latter and reducing or hydrolyzing. In examples, (1) tetrazotized 3 : 3<1>-diaminodiphenylurea is coupled with salicylic acid and 2: 8: 6-acid or its N- phenyl derivative; (2) an equimolecular mixture of the dystuffs m-nitraniline # salicylic acid or 1-naphthol-4-sulphonic acid (reduced) and mnitraniline -5- 1 : 8-dioxynaphthalene-3 : 6-disulphonic acid or N-phenyl-2: 8 : 6-acid (reduced) is treated with phosgene, (3) an equimolecular mixture of the dyestuffs 4-nitro-2-anisidine # salicylic acid (reduced) and m-aminoacetanilide # N-phenyl-2 : 8 : 6-acid (hydrolyzed) is phosgenated.