The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 01, 1977
Filed:
Dec. 21, 1973
Siegfried Schiessler, Frankfurt am Main, DT;
Ernst Spietschka, Oberauroff, Taunus, DT;
Wolfgang Tronich, Frankfurt am Main, DT;
Hoechst Aktiengesellschaft, Frankfurt am Main, DT;
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.