Conversion of crude polyhalocopper - phthalocyanine into pigment of high tinctorial

摘要

Process comprises treating 1 pbw. of the crude polyhalocopper phthalocyanine with from 0.5-5 pbw. of its wt. of chlorosulphonic acid in inert aromatic solvent at up to 150 degrees C. Treatment can be carried out in conventional preparation of polyhalocopper phthalocyanine by heating a tetrahalophthalic anhydride or tetrahalophthalonitrile in aromatic solvent inert to chlorosulphonic acid under process conditions and in presence of a Cu salt. Suitable solvents are chloro-, dichloro- and trichlorobenzenes and nitrobenzene and they are used in amount 3-8 pbw. to 1 pbw. crude dye.