Microwave-assisted Synthesis of Rosin Ethyl Ester in Ionic Liquid PTSA

In the presence of ionic liquid PTSA as solvent and catalyst,rosin ethyl ester was synthesized by esterification reaction of rosin with ethanol under microwave irradiation.Effects of catalyst type,ionic liquid type,ionic liquid dosage,reaction temperature,and reaction time on the esterification rate were investigated.The optimum conditions were found as follows: reaction temperature,100 ℃;reaction time,1 h;PTSA-to-rosin ratio,4∶1(mass).The esterification rate amounted to 95.5% under the optimum conditions.The ionic liquid was easily separated from the product and could be reused for several times.