Esterification of different FFAs with methanol by CERP/PES hybrid catalytic membrane for biodiesel production

Cation ion-exchange resin particles (CERP)/polyethersulfone (PES) hybrid catalytic membranes were prepared by immerse phase inversion for the esterification of different free fatty acids (FFAs) (such as, dodecanoic acid, tetradecanoic acid, hexadecanoic acid and octadecadienoic acid) with methanol. The membranes were characterized by SEM, ion-exchange capacity and swelling degree test. It is found that dodecanoic acid has the highest FFAs conversion among the four acids for its stronger acidic and reactivity. Different effects of membrane annealing temperature, reaction temperature, molar ratio of methanol to FFAs and catalytic membrane loading on the esterification were investigated by the esterification of dodecanoic acid with methanol. The dodecanoic acid conversion reaches 97.5% under the optimal condition when the esterification reaction lasted for 8 h.