METHOD OF DIACETONE-L-SORBOSE SYNTHESIS Russian patent published in 1998 - IPC

FIELD: chemical technology, production of vitamins. SUBSTANCE: method involves acetonation of L-sorbose in the presence of catalyst - 24% oleum (or equivalent amount of concentrated sulfuric acid) and dehydrating agent - zeolite NaA. Acetonation components were taken at ratio, mas. p. p.: L-sorbose : oleum : acetone = 1:(0.01-0.022):(13-16). Reaction is carried out at acetone boiling point for 4 h, then solution is cooled to (-10)-(-15) C, kept for 1 h and neutralized with alkali an aqueous solution to weak alkaline reaction (pH = 8-9). Diacetone-L-sorbose is isolated by extraction with chloroform followed by solvent distillation off or extraction with toluene followed by its distillation off. Product is used for synthesis of ascorbic acid. EFFECT: increased yield of product, decreased amount of sodium salt formed. 2 tbl