GB907843A - Improvements relating to metallisable monoazo dyestuffs, cobalt complex compounds thereof and their use - Google Patents

Abstract

The invention comprises monoazo dyestuffs of the formula <FORM:0907843/IV(a)/1> wherein A is a benzene radical, X is a carboxy or hydroxy group bound in o-position to the azo group, B is an alkyl, aralkyl, aryl or hydroaromatic radical and wherein A and B may be further substituted except by sulphonic acid or carboxyl groups not taking part in the complex formation, and cobalt complexes thereof (see Group IV(c)), which are used to dye cellulose acetate, and polyamides, in the mass. In an example the cobalt complex of 1-phenyl-3 - methyl - 4 - (2 - hydroxy - 5 - nitrophenylazo)-5-aminopyrazole is prepared, dissolved in a solution of acetylcellulose in acetone and the solution is spun in the usual way to give a brown thread. Reference has been directed by the Comptroller to Specifications 736,034 and 837,716.ALSO:The invention comprises monoazo dyestuffs of formula wherein A is a benzene radical, X is a hydroxy or carboxy group bound in o-position to the azo group, B is an alkyl, aralkyl, aryl or hydroaromatic radical and wherein A and B may be further substituted except by sulphonic acid or carboxyl groups not taking part in the complex formation; and cobalt complexes thereof. They are prepared by coupling in conventional manner a diazotised o-hydroxy- or -carboxy-aniline with a suitably substituted 3-methyl-5-aminopyrazole and if desired, treating the dye obtained possibly mixed with a similar or any other metallisable azo dyestuff with a cobaltyielding agent to give complexes containing one atom of cobalt bound to two dye molecules. The dyes give brown shades on wool and may also be used to dye silk, leather, synthetic polyamides, lacquers and cellulose acetate spinning masses (see Group IV(a)). In an example the dye 2-aminophenol-4-ethyl sulphone --> 1-(31-chlorophenyl)-3-methyl-5-aminopyrazole is prepared and heated with cobalt acetate in aqueous sodium carbonate solution to give the cobalt complex. Many similar examples, including the preparation of mixed complexes with metallisable mono- and dis-azo dyes, are specified. Reference has been directed by the Comptroller to Specifications 736,034 and 837,716.