Volume 7, Issue 3 (March 2010)
Biodiesel Synthesis via Recyclable Heterogeneous Catalyst: Titanium Niobate Nanosheet
A robust, heterogeneous, and recyclable catalyst to react upon broad range of feedstock for biodiesel processing so as to best utilize local oil/grease resources and whose optimal catalytic conditions are environmentally benign is sought to improve overall production of the alternative fuel. The application of titanium niobate nanosheets has been developed to transesterify soybean oil under environmentally favorable catalytic conditions. Experiments were conducted with a comprehensive study of the catalyst from its synthesis to analysis of the final biodiesel product. In the optimization of catalyst synthesis and its activation/reactivation, heating temperature and times and solvent washing were studied. The optimal catalyst was achieved with a 1:2:1 molar ratio of K2CO3:TiO2:Nb2O5 heated in a ThermoLyne® furnace at 500°C for 14 h. The application in biodiesel processing reached 99 % conversion in a flash reaction time of 5 min with a 1:2 methanol:soybean oil by weight and 6.5 wt % catalyst. Temperature was maintained at 66°C by a hot water jacket in a self-pressurized closed system. Initial reactions using used restaurant grease have shown 15 % conversion with optimization ongoing. Recycling and reactivating the catalyst have been studied and found to maintain efficiency in use. Transesterification was quantitatively analyzed by proton nuclear magnetic resonance spectroscopy. An innovative method designed to adhere the titanium niobate nanosheets to silica beads is underway with the intention of industrial scale biodiesel application.