Improved synthesis of sucrose fatty acid monoesters under ultrasonic irradiation

Sucrose fatty acid esters were synthesized by the transesterification of sucrose with aliphatic esters under ultrasound irradiation in good yield (?73%). The optimum reaction conditions for the transesterification reaction include a molar ratio of sucrose to fatty acid ethyl ester of 2:1 and the use of a 13% mol anhydrous K₂CO₃ catalyst. The optimum reaction temperature was set at 70 °C, the optimum reaction time was 2 h, and the optimum reaction pressure was 11 kPa. The reaction had excellent monoester selectivity. The proportion of monoester (6-monoester + 6′-monoester) in the purified products was up to 92–95% via flash column chromatography over silica gel, the ratios of 6-monoester/6′-monoester are 2.1–2.7, and the sucrose monoesters were identified by HPLC–MS, NMR and IR.