Microwave radiation for the synthesis of dibutyl malate

The dibutyl malate has been synthesized by malic acid and n-butyl alcohol,catalyzed by rejected perfluorosulfonic acid resin under microwave irradiation,the author has also studied the effects of synthetic conditions.The results show that the ester yield is 90.9% under the optimum operation conditions:the molar ratio of malic acid to n-butyl alcohol is 1∶5,the amount of catalyst is 0.7g,the reaction time is 25min and power of microwave irradiation is 400W.The catalyst is environment-friendly and easy to be recovered.The yield of dibutyl malate is still up to 78.6% after the catalyst is used for the sixth time.