Low-Al Zeolite Beta as a Heterogeneous Catalyst in Biodiesel Production from Microwave-Assisted Transesterification of Triglycerides

In this work microwave and reflux-assisted transesterification of triolein in methanol was carried out with alkali loaded low-Al Zeolite Beta as catalyst. The results show that the alkali-treated Zeolite Beta can effectively catalyze transesterification reaction of triglycerides to produce fatty acid ethyl esters (biodiesel), if Zeolite Beta has been properly modified with the alkali ion-exchange process. As a result, the final conversion yield over 90% could be obtained within an hour of reflux reaction. However, the durability of this Na-modified Zeolite Beta still has much room to be improved. In this work, this inferior catalytic durability is overcome by using the low-Al Zeolite Beta with a smaller particle size near 0.5 mu m. Consequently, for at least eight cycles, cyclic tests of these zeolite catalysts do not result in any significant decrease in catalysis in transesterification reaction. It is inferred that alkali cations existing in defect-sites of low-Al Zeolite Beta can be supplied to the surface of the catalysts during transesterification and enhance the catalysis. (C) 2014 The Authors. Published by Elsevier Ltd.