Synthesis of Ethyl Lactate with SO_4~(2-)/TiO_2-La_2O_3 Solid Acid as Catalyst

A solid acid catalyst was prepared by coprecipitation in ammonia with La(NO3)3.6H2O and TiCl4.Preparing conditions of the catalyst were molar ratio of TiCl4 and La(NO3)3.6H2O 8:1,-15℃ aging time 24 h,drying at 120℃ for 12h,concentration of sulfuric acid 0.5 mol/L,impregnation time 4 h,drying at 120℃ for 1h,calcination at 400 ℃ for 4h.As con-cerning synthesis of ethyl lactate,effects of catalyst dosage,molar ratio of ethanol to lactic acid,reaction time,dosage of water entrainer on esterification rate were studied.Under the optimal conditions of mole ratio of ethanol to lactic acid 2.0:1,reaction time 4 h,cyclohexane of 78% ethanol volume as water entrainer and mass of catalyst for 1.0% of lactic acid,esterification yield was 82 %.The solid superacid catalyst had the advantages of recycle and reusability.