Preparation of biodiesel from castor oil catalyzed by ionic liquid

The water-stable ionic liquidHSO4 is prepared and the transesterification of castor oil to biodiesel catalyzed by the ionic liquid is studied.At reflux temperature and under atmospheric pressure,the effects of molar ratio of methanol to castor oil,catalyst dosage(catalyst mass/ oil mass)and reaction time on the transesterification are studied.Under the optimal conditions as 9∶1 of molar ratio of methanol to castor oil,8% of catalyst dosage and reacin at reflux temperature under atmospheric pressure for 8 hours,the average yield of glycerine can reach 93%.The mole fraction of methyl ester in the product can be 96.7%,and the catalyst can be reused for several times.