Sulfated TiO2 supported molybdenum-based catalysts for transesterification of Jatropha seed oil: Effect of molybdenum species and acidity properties

A series of sulfated TiO2 supported Mo (xMo/1.5ST) catalysts were synthesized successfully and evaluated for the transesterification of Jatropha seed oil (JO) to biodiesel. Extensive characterization exhibits that the well dispersed Mo oxide species, with Mo6+ and Mo5+ oxidation states, were formed on the surface of the sulfated TiO2. The results indicate the presence of many sulfates species leads to the reduction of Mo6+ species to Mo5+ species. Furthermore, the catalytic activity of the xMo/1.5ST catalysts gradually increases with the increase of Mo-loading, although the sulfates content and the total acid intensity decrease. The transesterification process was fully investigated, and the 10Mo/1.5ST shows the highest yield of biodiesel of up to 97.42%. Additionally, the possible mechanism for the JO transesterification over Mo/1.5ST was described, and the fuel properties of the as-synthesized biodiesel conformed to the current international standards.