Submitted to: European Journal of Lipid Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2008
Publication Date: 3/1/2009
Citation: Joshi, H.C., Toler, J., Moser, B.R., Walker, T. 2009. Biodiesel from Canola Oil using a 1:1 Molar Mixture of Methanol and Ethanol. European Journal of Lipid Science and Technology. 111:464-473.
Interpretive Summary: Biodiesel is obtained by chemical reaction of lipids, such as animal fats or vegetable oils, with an alcohol. Methanol is normally the alcohol of choice because it is the least expensive. However, other alcohols, such as ethanol, can be used as well. With the continued emergence of the ethanol industry in the United States, we were interested in production of biodiesel from a mixed methanol/ethanol system as opposed to the commonly used single alcohol system. The experimental conditions for the production of canola oil biodiesel from a mixture of ethanol and methanol were optimized and the resulting fuel properties were analyzed. It was found that biodiesel produced from a mixture of ethanol and methanol in this study possessed enhanced lubrication ability and cold weather operability in comparison to biodiesel produced from methanol only. All other properties analyzed (viscosity, oxidation stability, acid value) were found to be essentially equivalent to biodiesel produced from methanol only. In summary, biodiesel produced from a mixture of methanol and ethanol satisfied the legal standards for biodiesel quality in the American and European markets (ASTM D6751 and EN 14214, respectively). Canola oil biodiesel produced from only ethanol was found to violate the viscosity requirements contained in the aforementioned European biodiesel standard, which in part explains why we chose to investigate a mixed methanol/ethanol system.
Technical Abstract: Canola oil was transesterified using an equimolar mixture of ethanol and methanol with potassium hydroxide (KOH) catalyst. Effect of catalyst concentration (0.5 to 1.5% wt/wt), molar ratio of equimolar mixture of ethanol and methanol (EMEM) to canola oil (3:1 to 12:1) and reaction temperature (25 to 75 deg C) on the percentage yield measured after 2.5 and 5.0 min were optimized using a central composite design with six center and six axial points. Statistical analysis demonstrated that catalyst concentration, molar ratio, and reaction temperature impacted percentage conversion at 2.5 minutes. However, reaction temperature did not influence percentage conversion at 5 minutes. Maximum percentage yield of 98% is predicted for catalyst concentration of 0.98% (wt/wt) and EMEM to canola oil molar ratio of 20:1 at a reaction temperature of 25 deg C. Maximum predicted percentage yield of 99% was obtained for a catalyst concentration of 1.0% (wt/wt) and any molar ratio at reaction temperature of 25 deg C at 5 minutes. The resultant biodiesel exhibited superior low temperature performance and lubricity properties in comparison to neat canola oil methyl esters and also satisfied ASTM D 6751 and EN 14214 standards with respect to oxidation stability, kinematic viscosity, and acid value.