High efficiency esterification and transesterification of alternative feedstock for biodiesel production

Free Fatty Acids (FFA) esterification and transesterification reactions were studied in presence of traditional and sonochemical assisted techniques, such as microwave (MW) and ultrasound (US). Several non edible oils, both of vegetable origin or waste oil were used. Acid ion exchange resins Amebrlyst\uae15 (A15) and 46 (A46) and Purolite\uae D5081 were used as catalysts for the FFA esterification. All the oils were successfully deacified over the resins, in particular A46 and D5081 showed a very good performance also after several recycles of use. Sonochemical methods were able to increase the conversion of the reactions. MW resulted to shorten the time to reach the plateau of conversion in FFA esterification, while US-assisted transesterification required lower reagents amount and much shorter times than the traditional one