GB674707A - Manufacture of disazo dyestuffs containing copper - Google Patents

Abstract

2 - (p - Carboxymethoxyphenyl - amino) - 5 - naphthol-7-sulphonic acid is prepared by treating with sodium bisulphite a neutralized mixture of J-acid and p-amino-phenoxyacetic acid.ALSO:The invention comprises the coppered disazo dyestuffs of the formula <FORM:0674707/IV (c)/1> where R is a naphthalene residue with 0-2 sulphonic acid groups and having the azo and O-Cugroups ortho to one another; such derivatives are prepared by coppering the dialkyl ethers of the parent dyestuffs under conditions such that the alkyl groups are split off. Thus copper tetrammine complexes may be used at 100 DEG C., with or without excess ammonia, or coppering may take place in the presence or ethanolamine as in Specification 644,883. The products can be used for dyeing and printing wool, silk or cellulosic fibres such as cotton, linen, artificial silk and staple fibres of regenerated cellulose. The dyeings (blue) are fast to light and crease-proofing. The parent disazo dyestuffs are obtained by coupling a tetrazotized 3 : 31-dialkoxy-benzidine with (in either order) one mol. of the N-carboxymethoxyphenyl derivative of J-acid (especially p-carboxymethoxyphenol) and one mol. of the appropriate o-coupling naphthol. In the examples, the starting materials are dianisidine, the above-mentioned p-substituted J-acid derivative and 1-naphthol-3 : 8-disulphonic acid or a second mol. of the same J-acid derivative. The dyeing of cotton is also exemplified. Other specified starting materials are 2-naphthol-4-and 6-sulphonic acids, 1-naphthol-3-, 4- and 5-sulphonic acids, 1-naphthol-3 : 6- and 4 : 8-disulphonic acids, 2-naphthol-3 : 6- and 6 : 8-disulphonic acids and 8-chloro- and 8-alkoxy-1-naphthol-3 : 6-disulphonic acids.