DK23175

1495442 Chlorinating copper phthalocyanines HOECHST AG 24 Jan 1975 [26 Jan 1974]3255/75 Heading C4P Unchlorinated or partially chlorinated copper phthalocyanine is reacted with chlorine under a partial pressure of at least 0À1 atmospheres gauge at temperatures up to 20‹ C. in fuming sulphuric acid in presence of iodine as catalyst; preferably in amounts of 0À05 to 0À5% by weight of the copper phthalocyanine. Oleum having a free sulphur trioxide content of 0À5 to 5À0% by weight is preferred and chlorination is continued until the product contains 2À5 to 6% by weight of chlorine. Water may be added to the product mixture to reduce the sulphuric acid concentration to 80-88% by weight at 20-80‹C. and the precipitated sulphate of chlorinated copper phthalocyanine is isolated, washed with sulphuric acid and hydrolysed in water. The product may be aftertreated by grinding or kneading in aqueous or aqueous-organic medium or by heating with water or an organic liquid. The pigments may be used to colour lacquers, printing inks, paints, paper, or natural, regenerated, semi-synthetic or synthetic polymers.