GB900354A - New metal complexes of monoazo dyestuffs and their production and use - Google Patents

Abstract

The invention comprises cobalt and chromium complex dyestuffs wherein the metal atom is attached to one or two azo dye radicals of formula <FORM:0900354/IV (b)/1> in which R1 and R2 are a hydrogen or halogen atom or an alkyl or alkoxy group, or to an azo dye radical of the above formula and either to a radical of another ortho: ortho1-dihydroxyazo dye free from sulphonic acid groups or to a radical of a colourless complex-forming compound. They are prepared by coupling in known manner a diazotised 2-alkoxyaniline with 1-(4-hydroxyphenyl)-pyrrolidone-(2) and metallising the azo dye so obtained, alone or in admixture with another such azo dye, or with another ortho:ortho1-dihydroxy azo dye free from sulphonic acid groups, with a cobalt- or chromium-yeilding agent. If the complex so obtained contains less than 2 dye radicals per metal atom it may be reacted further with a colourless complex-forming agent or with an ortho-ortho1-dihydroxyazo dye free from sulphonic acid groups. The dyes give red and violet dyeings or natural and synthetic polyamides. In an example the dye 1-amino-2 : 4-dimethoxy-5-chlorobenzene --> 1-(4-hydroxyphenyl)-pyrrolidone-(2) is prepared and converted into cobalt and chromium complexes in known manner. Further examples are given, including the preparation of mixed complexes. Specification 692,073 is referred to.