Study on Synthesis of Rosin Ester Under Microwave Irradiation

Esterification reactions of rosin with ethanol,butanol and pentanol under microwave irradiation were studied.Effects of catalysts and their dosages,molar ratio of alcohol to rosin,microwave power,reaction time on esterification were investigated.Results were as follows:(1) the optimum dosage of catalyst p-toluenesulfonic acid was 27%～30% of the mass of rosin;(2) the esterification ability of the alcohols with rosin was mainly determined by their spatial effects as CH3CH2OHCH3(CH2)2CH2OHCH3(CH2)3CH2OH;(3)as the length of carbon chain of alcohols increased,the optimum reaction time and the optimum microwave power increased,however,the optimum ratio of alcohol to rosin declined slightly;(4) acid value,esterification rate and IR spectroscopy elucidated the target products.