Process for the preparation of pyrocatechol and hydroquinone

US4362604A · kind A · utility

Assignee

• BAYER HEALTHCARE LLC · DE

Inventors

• Christoph Jupe · Cologne, DE
• Helmut Waldmann · Leverkusen, DE
• Jurgen Baumert · Cologne, DE
• Gunther Schummer · Stommeln, DE

Key dates

• Filing date: Aug 14, 1981
• Grant date: Dec 7, 1982
• Expiry date: Aug 14, 2001

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C37/60
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the isolation of hydroquinone, pyrocatechol, phenol and carboxylic acid from the reaction mixture containing the same such as one obtained by reaction of phenol with percarboxylic acid is disclosed. The reaction mixture is fed to a first rectification column and subjected to distillation whereby there is obtained a bottoms product containing pyrocatechol, hydroquinone and phenol. The top product is largely condensed and recycled, there being withdrawn from the top of the rectification column a mixture comprising phenol and carboxylic acid. The phenol and carboxylic acid mixture are continuously fed to a second rectification column where carboxylic acid is separated from phenol and substantially pure phenol is withdrawn from the stripping section and/or bottom of the second rectification column.