Process for the purification of copper phthalocyanine

US4010180A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Siegfried Schiessler · Frankfurt am Main, DE
• Ernst Spietschka · Idstein, DE
• Wolfgang Tronich

Key dates

• Filing date: Dec 21, 1973
• Grant date: Mar 1, 1977
• Expiry date: Dec 21, 1993

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B67/0019
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

A process for the purification of optionally substituted crude phthalocyanines wherein a phthalocyanine is introduced into a 84 to 88 % sulfuric acid, the phthalocyanine sulfate formed is subjected to a crystal growth at 60 - 100.degree. C in an inert gas atmosphere, the phthalocyanine sulfate is isolated and the phthalocyanine is recovered by hydrolysis with water. By this process a phthalocyanine sulfate is formed in a coarse crystalline form which can easily be filtered and which furtheron can easily be processed to a valuable pigment of the .alpha.-modification.