Studies on azo yellow pigments. III.

Studies on new water-insoluble monoazo pigments

Abstract

In “Studies on New yellow azo pigments (I) and (II)”, authors synthesized new six acetoacetarylides containing carbonamide group or carbonanilide group at benzene ring and prepared six water-insoluble disazo pigments, six water-insoluble monoazo pigments and forty-eight yellow monoazo lake pigments.
Upon testing the properties of these pigments, authors found that the pigment prepared from 1-acetoacetamino-2-methoxy benzene-5-carboramide had good resistance to light and organic solvents.
Then, authors synthesized twelve water-insoluble manoazo pigments shown in the following formula
X-N=N-CH-CO-CH₃-CONH-CH₃O-CONH₂
wherein X represents methyl group, methoxy group, chlorine atom or nitro group substituted at ortho-, meta-and para-position. Authors obtained these pigments by coupling 1-acetoacetamino-2-methoxy benzene-5-carbonamide with ortho-, meta- and para-substituted isomers respectively of toluidine, anisidine, chloroaniline and nitroaniline.
As a result of testing the effect of substituents on the properties of these pigments, the pigments containing nitro group gave generally reddish yellow shade and chlorine atom, methyl group or methoxy group gave greenish yellow shade. However, in these pigments no effect of substituent's position was recognized on the color shade.
On the fastness to light, negative group such as chlorine atom or nitro group gave better effect than positive group such as methyl group or methoxy group.
On the resistance to methanol and xylene, negative group gave more effective resistance than positive group.
These pigments had good resistance to ethyl acetate, regardless of the kind and position of substituents.
Above all, the pigments derived from o-chloro-aniline and o-nitroaniline had the best resistance to light and organic solvents