Synthesis of Glycerol Triacetate Using a Bronsted-Lewis Acidic Ionic Liquid as the Catalyst

Bronsted-Lewis acidic ionic liquids (IL) were used in the esterification of glycerol and acetic acid to produce glycerol triacetate. The results show that the IL (3-sulfonic acid)-propyltriethylammonium chloroironinate [HO3S-(CH2)(3)-NEt3]Cl-[FeCl3](x) (molar fraction of FeCl3, x = 0.67) was an efficient catalyst for the esterification reaction. The yield of glycerol triacetate and its content were greater than 98 % when reacted under reflux for 4 h. It was observed that a synergistic effect of Bronsted and Lewis acid sites enhanced the catalytic performance of IL. The reusability of IL was good. After six reaction cycles, the glycerol triacetate yield and concentration were still greater than 98 %. Likewise, the Bronsted-Lewis acidic IL was an efficient catalyst for esterification reactions of high boiling points alcohols with acetic acid.