CaO supported on mesoporous silicas as basic catalysts for transesterification reactions

A new group of basic catalysts supported on mesoporous solids has been prepared with the aim of being used as heterogeneous catalysis in biodiesel production. These catalysts based on calcium oxide supported on porous silica (SBA-15, MCM-41 and fumed silica) have been characterized and evaluated in transesterification processes. They were characterized by DRX, XPS, SEM, FT-IR, CO2-TPD and N-2 adsorption. The catalytic activity was evaluated in the transesterification of ethyl butyrate with methanol, and different reaction parameters were optimized by a factorial design response surface methodology. Thus, a sample containing 14 wt.% of CaO supported on SBA-15 was the most active, and, unlike commercial CaO, no lixiviation of the active phase was detected in the reaction medium. The transesterification activity of vegetable oils confirms the results obtained in the reaction of ethyl butyrate with methanol, reaching conversion as high as 95% with sunflower oil (after 5 h of reaction) and 65% (after 1 h) for castor oil. (c) 2007 Elsevier B.V. All rights reserved.