Facile Synthesis of Silane-Modified Mixed Metal Oxide as Catalyst in Transesterification Processes

The fast depletion of fossil fuels has attracted researchers worldwide to explore alternative biofuels, such as biodiesel. In general, the production of biodiesel is carried out via transesterification processes of vegetable oil with the presence of a suitable catalyst. A mixed metal oxide has shown to be a very attractive heterogeneous catalyst with a high performance. Most of the mixed metal oxide is made by using the general wetness impregnation method. A simple route to synthesize silane-modified mixed metal oxide (CaO-CuO/C₆) catalysts has been successfully developed. A fluorocarbon surfactant and triblock copolymers (EO)₁₀₆(PO)₇₀(EO)₁₀₆ were used to prevent the crystal agglomeration of carbonate salts (CaCO₃-CuCO₃) as the precursor to form CaO-CuO with a definite size and morphology. The materials show high potency as a catalyst in the transesterification process to produce biodiesel. The calcined co-precipitation product has a high crystallinity form, as confirmed by the XRD analysis. The synthesized catalyst was characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). The mechanism of surface modification and the effects of the catalytic activity were also discussed. The biodiesel purity of the final product was analyzed by gas chromatography. The optimum biodiesel yield was 90.17% using the modified mixed metal oxide CaO-CuO/C₆.