Process for the production of 2,3,5-trimethylhydroquinone diesters

US6316661A · kind A · utility

Assignee

• Degussa-Huels AG · DE

Inventors

• Steffen Krill · Mühltal, DE
• Horst Weigel · Rodenbach, DE
• Klaus Huthmacher · Gelnhausen, DE
• Nongyuan Shi · Hanau, DE
• Georg Markowz · Alzenau, DE
• Volker Hafner · Langenselbold, DE

Key dates

• Filing date: Jan 28, 2000
• Grant date: Nov 13, 2001
• Expiry date: Jan 28, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/582
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the production of 2,3,5-trimethylhydroquinone diesters by aromatization of 2,6,6-trimethyl-2-cyclohexene-1,4-dione (4-oxoisophorone, ketoisophorone, KIP) with an acylating agent and an acidic soluble or insoluble catalyst, which process may be operated alternatively continuously or discontinuously. The process includes the following steps: a) a carboxylic anhydride having a C.sub.1 to C.sub.4 alkyl residue is used as the acylating agent, b) after the reaction, a proportion of the resultant carboxylic acid is optionally removed by distillation, c) the reaction solution is cooled, d) the product which has crystallized out is separated and washed, and e) the filtrate is returned to step a).