Purification of indigo

US5424453A · kind A · utility

Assignee

• BASF SE

Inventors

• Reinhold Kohlhaupt · Bischofswerda, DE
• Udo Bergmann · Darmstadt, DE

Key dates

• Filing date: Jun 14, 1993
• Grant date: Jun 13, 1995
• Expiry date: Jun 14, 2013

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09B67/0014
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

This invention relates to a process for the purification of indigo, wherein the indigo is heated in an inert organic solvent at from 150.degree. to 250.degree. C. and preferably from 180.degree. to 220.degree. C.