Synthesis and characterization of acid-alkaline solid catalysts for biodiesel production

Abstract

In order to produce biodiesel by heterogeneous catalysis, solid catalysts of basic and acidic character, based on sodium and cerium supported on SBA-15 were synthesized. The obtained solids were characterized by low and high angle X-ray diffraction, BET method, temperature programmed desorption of carbon dioxide and FT-IR analysis with pyridine desorption. Then, their catalytic activity was evaluated in the transesterification reaction of commercial sunflower oil with absolute methanol, under the following conditions: 10 wt% of catalyst (based on oil mass), 40: 1 methanol to oil molar ratio, 60 °C and 5 h. Under these conditions, both the support and the 20Ce/SBA-15 catalyst were not active, while almost 98 wt% of biodiesel was obtained with the 5Na/20Ce/SBA-15 catalyst. Finally, the reuse of this catalyst was studied, obtaining a high activity (more than 90 wt% of biodiesel) in four additional cycles.