Process for the preparation of 1-amino-8-naphthol-4,6-disulphonic acid (k-acid)

US4609503A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Horst Behre · Odenthal, DE
• Heinz U. Blank · Odenthal, DE
• Willi Schossler · Cologne, DE

Key dates

• Filing date: Oct 8, 1980
• Grant date: Sep 2, 1986
• Expiry date: Oct 8, 2000

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C303/22
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The invention relates to a process for the preparation of 1-amino-8-naphthol-4,6-disulphonic acid (K-acid) as the mono-alkali metal salt by reacting a mixture of naphthylaminetrisulphonic acids and/or salts thereof with an alkali metal salt solution and separating the K-acid as the mono-alkali metal salt, by acidification and crystallization. The product is a known valuable dyestuff intermediate.