METHOD OF PREPARING ORANGE G PIGMENT Russian patent published in 2010 - IPC C09B41/00 C09B35/03 

FIELD: chemistry.

SUBSTANCE: invention describes a method of preparing orange G pigment, involving preparation of an aqueous suspension of 3,3'-dichlorobenzidine in the presence of a micellar solution of silver with particle size of 3-12 nm in a chemically pure isooctane solvent, diazotation of the obtained suspension of 3,3'-dichlorobenzidine in the presence of powder of iron nanoparticles with particle size of 50 nm and then filtration of the obtained solution of the diazo-compound in the presence of powder of iron nanoparticles with particle size of 15-50 nm to obtain a purified solution of the diazo-compound, preparation of a solution of a sodium salt of 1-phenyl-3-methyl-5-pyrozolone in the presence of powder of nanoparticles of an alloy of nickel and chromium with particle size of 15-50 nm and azo-coupling of the solution of diazo-compound and the solution of the sodium salt of 1-phenyl-3-methyl-5-pyrazolone in the presence of a mixture of 10-20% micellar solution of copper in chemically pure isooctane solvent with copper particle size of 3-12 nm and powder of nanoparticles of nickel with particle size of 15-50 nm.

EFFECT: method simplifies the technology owing to exclusion of a large amount of acid wastes and reduction of the amount of surfactants, and enables to obtain orange G pigment with a fine crystalline structure, high optical concentration, depth and colour saturation.

15 tbl, 3 ex