Heterogeneous CaO–MoO3–SBA-15 catalysts for biodiesel production from soybean oil

• Solid catalysts were used for biodiesel production in a heterogeneous manner.
• The catalyst could give the oil conversion of 83.2%.
• The catalyst was characterized by using various techniques.

The main aim of this research is to develop efficient and environmentally benign heterogeneous catalysts for biodiesel production. For this purpose, heterogeneous CaO–MoO3–SBA-15 catalysts were prepared by incipient impregnation method, and the prepared catalyst was tested for the transesterification process of soybean oil to produce biodiesel. Various techniques such as X-ray diffraction, Fourier transform infrared spectra, X-ray photoelectron spectroscopy, scanning electron microscopy and thermo gravimetric analysis were employed for the characterization of the solid catalyst. The catalytic activity was dependent on the calcination temperature and loading amount of calcium and molybdenum oxides. The solid catalyst, with the CaO–MoO3 loading of 40% and calcined at 823 K, showed the best catalytic activity. The effect of methanol/oil molar ratio, reaction time, catalyst loading and catalyst stability was investigated. By using a 6 wt.% of catalyst with methanol/oil molar ratio of 50:1 at reflux of methanol, the oil conversion of 83.2% after 50 h of reaction, could be achieved over the solid catalyst. The catalyst can be easily recovered and reused without significant loss of activity.