METHOD OF PRODUCING CRYSTALLINE D-SORBITOL

摘要

PCT No. PCT/EP97/03924 Sec. 371 Date Apr. 19, 1999 Sec. 102(e) Date Apr. 19, 1999 PCT Filed Jul. 21, 1997 PCT Pub. No. WO98/03457 PCT Pub. Date Jan. 29, 1998The continuous process for making crystalline D-sorbitol using a melt crystallizer consisting of a cooled container and a horizontally arranged rotatable shaft equipped with disk elements and mixing parts to form a worm includes evaporating an aqueous D-sorbitol solution at 5 to 200 mbar and at a temperature of 130 DEG to 170 DEG C. in vacuum, advantageously in a thin film evaporator, to obtain a D-sorbitol melt containing less than 0.5 % by weight water; cooling the D-sorbitol melt to a temperature of 5 to 15 DEG C. above a solidification point of the D-sorbitol melt; melt crystallizing the D-sorbitol melt obtained during the evaporating in the melt crystallizer with an average dwell time of 1 to 5 hours to form D-sorbitol crystals and grinding and sieving the D-sorbitol crystals formed during the melt crystallizing of step d) to form a D-sorbitol end product containing more than 90% by weight of a gamma modification of crystalline D-sorbitol. During the process no solid D-sorbitol is added to the D-sorbitol melt in order to form initial crystallization nuclei for crystallization and no subsequent maturation steps of the end product are included in the process.