Synthesis of glycerol triacetate using acidic functional ionic liquid as catalyst

[HSO3-pmim]Cl,[HSO3-pmim][BF4],[Hpyro][HSO4]and[HSO3-pmim][PTSA] ionic liquids were synthesized and the their structures were characterized by 1H-NMR and FT-IR.Glycerol triacetate was synthesized by using these acidic functional ionic liquids as catalyst,and an ionic liquid [HSO3-pmim][PTSA] with better catalytic performance was selected and could be repeatedly used.The influences of the amount of catalystr,aw material proportionr,eaction time and reaction temperature on the reaction were investigated.The optimum conditions were obtained as follows:n(glycerol)︰n(acetic acid)=1︰8,catalyst amount 10.5% the total weight of glycerol and acetic acid,reaction time 6 h and reaction temperature 120 ℃.Repeated use of the ionic liquid was investigated.Under the optimum conditions,when the catalyst was repeatedly used for 7 times,the yield of glycerol triacetate still reached 90%.