Method for the synthesis of sucrose-6-esters

Abstract

There is described a process for the synthesis of a sucrose-6-ester comprising: (a) reacting a mixture comprising sucrose and a polar aprotic solvent with an organotin-based acylation promoter, while adding a solvent capable of removing water by co-distillation, and removing water by co-distillation, to afford a first reaction mixture which is substantially free from water, followed by (b) adding a carboxylic anhydride to said first reaction mixture to afford a second reaction mixture, and maintaining said second reaction mixture at a temperature and for a period of time sufficient to produce a sucrose-6-ester, characterised in that step (a) is performed at a temperature of from 85 to 125° C. and at a pressure of from 20 to 80 kPa. In the most preferred embodiment, the polar aprotic solvent is DMF, the solvent capable of removing water by co-distillation is cyclohexane, the organotion-based acylation promoter is a 1,3-diacyloxy-1,1,3,3-tetrabutyldistannoxane, and step (a) is performed at approximately 97° C., and approximately 50 kpa, until the weight ratio of tin to water in the first reaction mixture is greater than about 26, when the tin content is measured by X-Ray Fluoresence Analyzer, and the water content is measured by the Karl-Fischer method.