Process for the preparation of naphthalene-1,3,6-trisulphonic acid

US4180521A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Horst Behre · Odenthal, DE
• Rolf Putter
• Guido Steffan · Odenthal, DE

Key dates

• Filing date: Mar 15, 1978
• Grant date: Dec 25, 1979
• Expiry date: Mar 15, 1998

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C309/00
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process has been invented for the preparation of naphthalene-1,3,6-trisulphonic acid by sulphonating naphthalene with sulphuric acid and oleum, characterized in that naphthalene and most of the oleum are simultaneously metered into sulphuric acid or oleum of low concentration, which has been initially introduced, at about 140.degree. to 240.degree. C., the temperature is kept at about 140.degree. to 240.degree. C. for some time, the remainder of the oleum is then added at about 140.degree. to 240.degree. C. and the mixture is then further stirred for some time. Naphthalene-1,3,6-trisulphonic acid is a known important intermediate used, for example, in the preparation of T-acid, H-acid and chromotropic acid.