PROCESS FOR THE PRODUCTION OF ALPHA-TOCOPHEROL ACETATE BY CONDENSATION OF TRIMETHYLHYDROQUINONE AND ISOPHYTOL WITH RECIRCULATING ACETIC CATALYTIC SOLUTION

摘要

Production of alpha -tocopherol acetate in a recirculating process involves condensation of trimethylhydroquinone and isophytol in presence of a catalyst system comprising zinc halide and an aqueous protonic acid and optionally an elemental metal in a polar solvent/water mixture and subsequent acylation of the resultant alpha -tocopherol. Production of alpha -tocopherol acetate (I) in a recirculating process involves condensation of trimethylhydroquinone and isophytol in presence of a catalyst (II) system comprising zinc halide (IIa) and an aqueous protonic acid (IIb) 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 (II) obtained after working up by aqueous extraction is regenerated and the solution containing acetic acid is returned to the reaction. (II) is concentrated and reintroduced into the reaction in liquid form.