GB597414A - Manufacture of azo-dyestuffs - Google Patents

Abstract

Azo dyestuffs are manufactured by coupling one molecular proportion of tetrazotized 4 : 41-diaminodiphenylurea - 3 : 31 - dicarboxylic acid with two molecular proportions of a 1-phenylpyrazolone, or one molecular proportion of each of two different 1-phenylpyrazolones, containing, or each containing, an -SO2NH2 group in the phenyl residue; or by coupling such a pyrazolone with a diazotized 2-aminobenzene-1-carboxylic acid containing in the 5-position a substituent convertible into an amino group (e.g. a nitro or acylamino group), converting this substituent into an amino group (e.g. by reduction or hydrolysis), and condensing two molecular proportions of the aminoazo compound with one of phosgene. The products are suitable for dyeing or colouring leather, wool, superpolyamide fibres, plastic masses and gelatine, and especially for dyeing or printing cellulosic fibres, e.g. linen, cotton, or artificial silk or staple fibres of regenerated cellulose. They may be treated in substance, in the dyebath or on the fibre with an agent yielding metal, e.g. chromium, cobalt or especially copper. In examples: (1) 4 : 41-diaminodiphenylurea-3 : 31-dicarboxylic acid (1 mol.) is tetrazotized and coupled with 2 mols. of 1-(31-or 41-sulphonamidophenyl)-3-methyl-5-pyrazolone or 1 mol. each of the 31- or 41-compounds; (2) 5-nitro-2-aminobenzoic acid is diazotized and coupled with 1-(31-sulphonamidophenyl)-3-methyl-5-pyrazolone, the nitro group is reduced by means of sodium sulphide, and the product is treated with phosgene in aqueous sodium carbonate solution; (3) cotton is dyed with the product of (2) from a bath containing sodium carbonate and, in the latter stages, Glauber salt, and is after-treated in the same bath with complex copper sodium tartrate, yielding a brown-yellow dyeing. Specifications 215,769, [Class 2 (iii)], and 455,274 are referred to. The Specification as open to inspection under Sect. 91 comprises also the use, as tetrazo components, of further substituted 4 : 41-diaminodiphenylurea-3 : 31-dicarboxylic acids, and, as coupling components, of other arylpyrazolones containing a sulphonamide group, including those in which the sulphonamide group is substituted on the nitrogen atom, e.g. by alkyl or hydroxyalkyl groups. This subject-matter does not appear in the Specification as accepted.