Studies on Azo yellow pigments. I.
Studies on New Water-Insoluble disazo pigments
1966 Volume 39 Issue 2 Pages 62-68
Details
1966 Volume 39 Issue 2 Pages 62-68
Benzidine Yellows are the most important yellow pigment of disazo type for printing inks, paints, colouration of plastics, rubber, etc. In benzidine yellow pigments, it is known that the colour shade and the fastness to light and to organic solvents change by the influence of the substituents contained in benzene ring of acetoacetanilide, Authors tested the properties of new disazo pigment containing carbonamide or carbonanilide group in benzene ring of acetoacetanilide.
Thus authors synthesized six acetoacetarylides, namely 1-acetoacetamino-benzene-3-carbonamide, 1-acetoacetamino-2-methoxy-benzene-5-carbonamide, 1-acetoacetamino-2-chlorobenzene-5-carbonamide, 1-acetoacetamino-benzene-3-carbonanilide, 1-acetoacetamino-2-methoxy-benzene-5-carbonanilide and 1-acetoacetamino-2-chloro-benzene-5-carbonanilide, and the six disazo pigments thus prepared are shown by the following formula :
Y.HNOC-X-HNCO-CH-CO-CH3-N=N-Cl-Cl-N=N-CH-CO-CH3-CONH-X-CONH.Y
wherein X represents hydrogen atom, chlorine atom or methoxy group, Y represents hydrogen atom or phenyl group.
Authors could obtain these acetoacetarylides from the corresponding aromatic amine containing carbonamide group or carbonanilide group by the reaction of diketene or ethyl-acetoacetate. Then, authors prepared six pigments by coupling tetrazotized 3, 3'-dichlorobenzidine with acetoacetarylides.
The disazo pigments newly synthesized gave generally reddish yellow shade. All pigments gave very good resistance to organic solvents than the well known benzidine pigments. Especially in the resistance to methanol and ethyl-acetoacetate, the three pigments containing carbonamide group gave better resistance than carbonanilide group. Also authors found that the methoxy group of the coupling component gave better effect in the resistance to light and organic solvents.
As a result, the pigment prepared from 1-acetoacetamino-2-methoxy-benzene-5-carbonamide gave excellent resistance to light and organic solvents.
