Process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic acid and 1-aminonaphthalene-7-sulphonic acid

US4873026A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Horst Behre · Odenthal, DE
• Heinz U. Blank · Odenthal, DE
• Gerhard Marzolph · Cologne, DE
• Willi Streicher · Krefeld, DE

Key dates

• Filing date: Oct 4, 1988
• Grant date: Oct 10, 1989
• Expiry date: Oct 4, 2008

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C303/06
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

New process for the preparation of 1-aminonaphthalene-2,4,7-trisulphonic acid and, if appropriate, 1,7-Cleve's acid, in which 1-nitronaphthalene is reacted by the Piria method with bisulphites in a manner which is known per se, the sulphamate mixture obtained in this Piria reaction is sulphonated with sulphur trioxide in sulphuric acid to give 1-aminonaphthalene-2,4,7-trisulphonic acid and, if appropriate, this is hydrolysed to 1,7-Cleve's acid by heating in aqueous sulphuric acid.