Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: February 14, 2005
Publication Date: May 1, 2005
Citation: Haas, M.J., Scott, K.M., Marmer, W.N. 2005. Direct production of biodiesel from lipid-bearing materials [abstract]. Annual Meeting and Expo of the American Oil Chemists' Society. p. 60. Technical Abstract: Biodiesel is conventionally synthesized by the incubation of refined fats and oils with alcohol containing a catalyst, generally sodium hydroxide (NaOH). The resulting fatty acid ester product is generally unable to compete economically with petroleum-derived diesel fuel. Through the development of alternate processes for biodiesel synthesis it may be possible to reduce the cost of this renewable, low-pollution fuel. We have previously demonstrated that the use of refined oil in biodiesel production is not strictly necessary, and that it is possible to produce fatty acid esters by the direct exposure of soybeans to alkaline methanol (Haas et al., JAOCS, 81, 83-89, 2004). The method, termed 'in situ transesterification', involves simply the shaking of the soy flakes in methanol containing NaOH, at ambient temperature. Using dry flakes and optimal reactant ratios, quantitative transesterification of the flake lipid was achieved in a 5.5 h reaction. The resulting ester product met the ASTM specifications for biodiesel. We have now examined the utility of this approach for the synthesis of fatty acid methyl esters from other feedstocks. The production of industrial ethanol from corn generates a coproduct known as 'distillers dried grains' or ddg. The lipid content of this material is approximately 10%. This lipid is transesterified, yielding fatty acid methyl esters, during incubation with alkaline methanol. Similarly, we have determined that rapeseed oil resident in canola seeds is converted to fatty acid methyl esters when subjected to in situ transesterification. Breakage of the seeds is essential in order to achieve appreciable degrees of transesterification. Meat and bone meal is a coproduct of the meat industry, containing approximately 9% lipid. This lipid was converted at very high efficiency to fatty acid methyl esters when incubated directly with alkaline methanol. The details of the transesterification of these various feedstocks, which establish the generality of the in situ approach, will be discussed.