Process for the isolation of 2-naphthylamine-1,5-disulphonic acid

US5248812A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Horst Behre · Odenthal, DE
• Heinz U. Blank · Odenthal, DE
• Holger Heidenreich · Cologne, DE
• Fritz Pohl · Wittmund, DE
• Paul Uhrhan

Key dates

• Filing date: Sep 2, 1992
• Grant date: Sep 28, 1993
• Expiry date: Sep 2, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C303/44
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

When 2-naphthylamine-1,5-disulphonic acid is precipitated from the as-sulphonated reaction mixtures by dilution, a purer product is obtained, with a low level of adherent sulphuric acid, if the precipitation by dilution of the reaction mixture is carried out under precisely defined conditions.