PRODUCTION OF ALPHA-TOCOPHEROL ACIDIC SUCCINIC ACID ESTER CALCIUM SALT

PROBLEM TO BE SOLVED: To obtain the subject compound which is formulated with a vitamin E-containing tablet as a vitamin E for stock medicine for direct tableting, by reacting α-tocopherol acidic succinic acid ester with a calcium acetate in a hydrous methanol solvent. SOLUTION: A solution obtained by dissolving α-tocopherol acidic succinic acid ester of formula I in hydrous methanol and a solution prepared by dissolving a calcium acetate in an amount corresponding to 1/2 mol of the compound of formula I in water or preferably 50-70% hydrous methanol while stirring are subjected to salt exchange by gradually dripping the solution of calcium acetate to the solution of the compound preferably at a room temperature for requiring 1-3 hours to give the objective compound of formula II. Calcium acetate monohydrate which is stable free from irradiation/hygroscopicity and inexpensively suppliable as a high-quality raw material on the market is preferably used as the calcium acetate. Methanol can be recovered in high purity and used since it is excellent in crystallizing ability of the compound of formula II and does not form an azeotropic mixture with water in recovering methanol from a hydrous reaction system.