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PREPARATION OF ASCORBIC ACID-2-PHOSPHATE, AND PREPARATION OF POTASSIUM MAGNESIUM-L-ASCORBATE-2- PHOSPHATE, K1+-0.3 MG1+-0.15-L-ASCORBATE-2-PHOSPHATE AND 5,6-ISOPROPYLIDENE-ASCORBIC ACID
PREPARATION OF ASCORBIC ACID-2-PHOSPHATE, AND PREPARATION OF POTASSIUM MAGNESIUM-L-ASCORBATE-2- PHOSPHATE, K1+-0.3 MG1+-0.15-L-ASCORBATE-2-PHOSPHATE AND 5,6-ISOPROPYLIDENE-ASCORBIC ACID
Process for the preparation of ascorbic acid 2-phosphate by reacting ascorbic acid or ascorbic acid derivatives with POCl3 in the presence of a tertiary amine in an appropriate aqueous solvent at temperatures of -10 to 25 DEG C, while maintaining a pH of about 8 to 13.5 with KOH throughout the whole phosphorylation reaction and subsequently isolating of the ascorbic acid 2-phosphate, characterised in that the reaction mixture produced on phosphorylation is treated with the aqueous solution of a magnesium compound without previous ion exchange treatment until the formation of crystalline KMgPO4 has terminated, the crystallised KMgPO4 is separated off, the filtrate so obtained is concentrated at a pH of 6 to 11 and/or treated with 0.1 to 5 times the amount, relative to the concentrated filtrate, of a primary lower alkanol or acetone, and cooled with stirring until the KCl has stopped crystallising out, and the ascorbic acid phosphate is isolated in a known way from the reaction solution, obtained after separating off KCl, which is largely free of inorganic salts. It is especially advantageous to isolate the ascorbic acid 2-phosphate in the form of the new potassium magnesium ascorbate 2-phosphate, for which patent protection is also applied for. The process is especially advantageous if 5,6-isopropylidene- ascorbic acid is used as the ascorbic acid derivative, this being obtained by reacting ascorbic acid with acetone in the presence of oleum. The process is of particular importance for the preparation of L-ascorbic acid 2-phosphate.
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