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US 6,441,199 B2Granted
Process for the production of α-tocopherol acetate by condensation of trimethylhydroquinone with isophytol with recycling of an acetic catalyst solution
AssigneeDegussa AG
InventorsSteffen Krill, Stepahn Kretz, Klaus Huthmacher
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Abstract
A process for the production of α-tocopherol acetate in a recirculating process by condensation of trimethylhydroquinone and isophytol in the presence of a catalyst system 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, and subsequent acylation of the resultant α-tocopherol and recirculation of the catalyst system.
Claims9
A process for the production of α-tocopherol acetate in a recirculating process comprising:
- condensing trimethylhydroquinone and isophytol in the presence of a catalyst system comprising a zinc halide and an aqueous protonic acid and, optionally, an elemental metal, in a polar solvent/water mixture that is extractable or miscible with water, wherein:
- i) α-tocopherol initially obtained in the condensation reaction is separated from an aqueous catalyst phase and esterfied with an accylating agent,
- ii) a 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
- iii) the mixture of catalysts comprising zinchalide and protonic acid is concentrated and reintroduced into the reaction in liquid form.
1 more element
Dependencies are inferred from the claim text.