Catalytic activity of mesoporous V/SBA-15 in the transesterification and esterification of fatty acids

Mesoporous V/SBA-15 with different weight percentages (1, 2.5 and 5 wt%) of vanadia was prepared via the wet impregnation method. The mesoporous nature of the catalysts were investigated, using the X-ray diffraction analysis, N2 adsorption–desorption isotherm and scanning electron microscope. All the catalysts showed the highly dispersed vanadia was confirmed by the result of the diffuse reflectance UV vis technique. From the NH3-temperature programmed desorption, it is observed that, the acidity values of the prepared catalysts are in the range 72–102 µmol/g. 5 % V/SBA-15, possesses Bronsted and Lewis acid sites ensured by pyridine-adsorbed Fourier-transform infrared method. The acidity of the catalyst was experimented in the transesterification of sunflower oil. The reaction conditions were optimized with maximum conversion (100 %) of sunflower oil into biodiesel and the activity of the catalyst was found to be more in 5 wt% V/SBA-15 at 140 °C. Different fatty acids like butyric, valeric, caprylic and oleic acid were also studied under optimized conditions, and the isolated product was confirmed from the H1 NMR spectroscopy.