Preparation of .alpha.-tocopherol or .alpha.-tocopheryl acetate by reacting trimethylhydroquinone and phytol or isophytol, with recycling of the zinc halide condensation catalyst

US6005122A · kind A · utility

Assignee

• BASF SE

Inventors

• Kai-Uwe Baldenius · Ludwigshafen, DE
• Wulf Kaiser · Bad Dürkheim, DE
• Bernhard Bockstiegel · Wasserburg am Inn, DE
• Harald Laas · Frankenthal (Pfalz), DE
• Bernhard Schulz · Schwetzingen, DE
• Peter D. Schmitt · Lambsheim, DE
• Helmut Glietenberg · Ludwigshafen, DE

Key dates

• Filing date: Dec 12, 1997
• Grant date: Dec 21, 1999
• Expiry date: Dec 12, 2017

Classification

• Technology area (CPC B): Performing Operations; Transporting
• CPC primary: B01J27/138
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for preparing .alpha.-tocopherol or .alpha.-tocopheryl acetate by reacting 2,3,5-trimethylhydroquinone with isophytol or phytol in the presence of a zinc halide condensation catalyst and a proton donor in a solvent with or without subsequent esterification with acetic anhydride, which comprises PA0 A. carrying out the reaction in a nonpolar solvent which is only slightly water-miscible, if at all and PA0 B. introducing the required zinc halide into the reaction in the form of a mixture of from 1 to 4 mol of water per mol of zinc halide. The possibility of introducing the zinc halide required in the process according to the invention in the form of a mixture of zinc halide and water which can be readily handled and metered at from 50 to 200.degree. C. without impairing the yield and purity of the tocopherol opens the way to an advantageous recycling of the zinc halide after the reaction by separating off or extracting and recycling the zinc halide in the form of a from 60 to 90% strength by weight solution or pumpable magma.