GB849376A - New disazo pigments - Google Patents

Abstract

Diamines of formula NH2-X-NHCO-Y-CONH-X-NH2, wherein X is a substituted or unsubstituted benzene ring having the-CONH-and-NH2-groups in the meta-or para-positions and Y is an arylene radical optionally substituted by halogen, are prepared by reacting a functional derivative (e.g. anhydride, ester or acid chloride) of an aryl dicarboxylic acid with a m-or p-nitroaniline and reducing the nitro groups to amino groups. They are used as components in the preparation of disazo pigments (see Group IV(c) ). In an example a mixture of 2-chloro-4-nitroaniline, terephthaloyl chloride and toluene is refluxed and the precipitated N: N1-di(21-chloro-41-nitrophenyl)-terephthalamide is filtered off and reduced with iron and hydrochloric acid in ethanol to N : N1-di (21-chloro-41-aminophenyl)-terephthalamide. Diamines specified include N : N1-di (21-methoxy51-aminophenyl) isophthalamide, N : N1-di (21-methyl-41-aminophenyl) terephthalamide, 2 : 5-dichloro - N : N1 - di (21 - methoxy - 51 - amino - phenyl) - terephthalamide and N : N1 - di (21 - methoxy-51-aminophenyl)-naphthalamide.ALSO:The invention comprises disazo pigments of formula: <FORM:0849376/IV (c)/1> wherein R is an alkyl or aryl radical, Ar is an aryl radical, X is a substituted or unsubstituted benzene ring wherein the -CONH- and -N=N-groups are in the meta- or parapositions to each other and Y is an arylene radical optionally substituted by halogen. They are prepared by coupling 2 moles of an amide of formula R.COCH2 CONHAr with 1 mole of a tetrazorised diamine of formula H2N-X-NHCO-Y-CONH-X-NH2. Alternatively they may be prepared by reacting 1 mole of a functional derivative (e.g. anhydride, ester or acid halide) of an aryl dicarboxylic acid with 2 moles of an aminoazo compound of formula: <FORM:0849376/IV (c)/2> The pigments are used to colour rubber, synthetic polymers and paints in yellow shades. In an example N : N1-di(21-chloro -41- aminophenyl)- terephthalamide is tetrazotised and coupled with acetoacet -mxylidide. Further components specified include N : N1 -di(21-methoxy -51- aminophenyl)-isophthalamide, 2-chloro- or 2 : 5-dichloro-N : N1-di(21-chloro41- aminophenyl)-terephthalamide and N : N1-di(21-methoxy-51-aminophenyl)-naphthalamide; acetoacet(4-chloro -2 : 5- dimethoxy) anilide, benzoylacetanilide and acetoacet-alpha-naphthylamide.