Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/1/2011
Publication Date: 9/1/2011
Citation: Ngo, H., Xie, Z., Kasprzk, S., Haas, M.J., Lin, W. 2011. Catalytic synthesis of fatty acid methyl esters from extremely low quality greases. Journal of the American Oil Chemists' Society. 80:1417-1424. Interpretive Summary: After thirty years of research, Biodiesel (BD) is just entering the overall US fuel supply chain, with annual production rising from 2 to 650 million gallons between 2000 and 2008. In comparison to petrodiesel, BD is a viable alternative biofuel that has tremendous environmental benefits. However, the current technologies for BD production are not cost-competitive to petrodiesel in the absence of federal subsidies. In collaboration with a university partner, we have developed a new catalytic route that can efficiently convert very low quality feedstocks to BD. The improved process does not use refined and expensive feedstocks, and therefore does not compete with food crops. The BD products from this process do not require extensive washing with water to clean them up. This process is thus potentially more environmentally friendly and sustainable. This research project provides a great opportunity for the diversification of the US agricultural markets for currently under-utilized, low-grade fat and oil feedstocks.
Technical Abstract: Biodiesel (BD) is a renewable fuel for compression ignition engines that is composed of the simple alkyl esters, usually methyl-, of fatty acids (FAME). It is typically produced via base-catalyzed transesterification between refined vegetable oil or animal fat (e.g., soybean oil, tallow) and an alcohol (e.g., methanol). This process can, however, be marginally cost-effective due to the high feedstock and processing costs. It is thus desirable to develop new catalytic routes that can efficiently convert the less expensive feedstocks to BD. We report here the applications of a series of diarylammonium based homogeneous and heterogeneous catalysts for converting a particularly low value, low quality lipid, trap grease to FAME. In the course of a 1 h reaction at 125 oC these catalysts simultaneously esterified the free fatty acids (>90 wt% of the substrate) and transesterified the acylglycerols (<10 wt%) of the feedstock to FAME with greater than 95% overall conversion.