No abstract

To date, the standardized method for glycerol quantification in biodiesel production utilizes gas chromatography (GC); however, availability to manufacturers and instrumentation cost limits GC as an analytical method for general quality enforcement among producers. The method developed here is a bench top technique for quantitative determination of glycerol in biodiesel, with practical application in pharmaceutical and environmental quality control. The method extracts the glycerol contaminant from biodiesel using a normal phase solid phase extraction column (SPE). The protocol proceeds by rinsing with hexane to remove residual methyl esters, then collecting the glycerol with water. The aqueous extract is analyzed spectrophotometrically by an anthrone coloring reagent. Use of 2-g SPE columns and the solvent system developed has achieved 85% glycerol recovery. The assay applied has a detection range of 0.004-0.400% free glycerol, comparable to the established American Society of Testing and Materials (ASTM) D 6584-07 GC technique. Results were confirmed by GC and high-pressure liquid chromatography (HPLC). The bench top technique reduces the costs of operation relative to current methods, completes analysis in proficient time, requires minimal labor, and has analytical limits comparable to existing standard methods of biofuel analysis.

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.