Preparation of pure trans- and cis-4-Hydroxy-2,2,6-trimethylcyclohexan-1-one from isomerc mixtures

US5777173A · kind A · utility

Assignee

• BASF SE

Inventors

• Joachim Paust · Schifferstadt, DE
• Wolfgang Kriegl · Ludwigshafen, DE
• Horst Hartmann · Dresden, DE

Key dates

• Filing date: Nov 19, 1996
• Grant date: Jul 7, 1998
• Expiry date: Nov 19, 2016

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C45/82
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of pure trans- and cis-4-hydroxy-2, 2,6-trimethylcyclohexan-1-one from a mixture of these isomers comprises fractionally rectifying the isomeric mixture in a suitable column having from about 30 to 80 theoretical separation stages at temperatures of preferably from 50.degree. to 130.degree. C. and a pressure in the range from 0.1 to 5 mbar. The products are essential intermediates for the preparation of 3-hydroxycarotenoids such as cryptoxanthin and zeaxanthin.