Process for preparing aromatic hydroxycarboxylic acids

US4529817A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Gerhard Stopp · Leverkusen, DE
• Horst Karkossa · Leichlingen, DE
• Viktor Trescher · Leverkusen, DE

Key dates

• Filing date: Mar 7, 1983
• Grant date: Jul 16, 1985
• Expiry date: Mar 7, 2003

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C51/15
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Aromatic hydroxycarboxylic acids are prepared by reacting an alkali metal salt of an aromatic hydroxy compound in solid phase with carbon dioxide, by reacting an alkali metal salt of an aromatic hydroxy compound in the form of granules in a fluidized bed with carbon dioxide, if desired under elevated pressure, at first at temperatures of 20.degree. to 130.degree. C. until at least 40% of the hydroxy compound has been converted into the corresponding carbonate, then completing the reaction at temperatures of 135.degree. to 300.degree. C., and then converting the reaction product obtained into the free acid.