METHOD FOR PREPARING ALPHA-TOCOPHEROL ACETATE BY CONDENSING TRIMETHYLHYDROQUINONE WITH CIRCULATED ACETIC CATALYST SOLUTION

摘要

PURPOSE: A method for preparing alpha-tocopherol acetate is provided by condensing trimethylhydroquinone with circulated acetic catalyst solution. CONSTITUTION: In the method for the production of alpha-tocopherol acetate in a recirculating process by condensation of trimethylhydroquinone and isophytol in the presence of a catalyst system consisting of a zinc halide and an aqueous protonic acid and optionally an elemental metal in a polar solvent/water mixture extractable or miscible with water, the alpha-tocopherol initially obtained is separated from the aqueous catalyst phase and esterified with an acylating agent, the solution of the catalysts obtained after working up by aqueous extraction is regenerated and the solution containing acetic acid is returned to the reaction and the catalyst mixture comprising zinc halide and protonic acid is concentrated and reintroduced into the reaction in liquid form.