Submitted to: Annual Meeting and Expo of the American Oil Chemists' Society
Publication Type: Abstract Only
Publication Acceptance Date: 5/5/2002
Publication Date: 5/5/2002
Citation: DUNN, R.O., KNOTHE, G.H. PREDICTING THE OXIDATIVE STABILITY OF BIODIESEL. ANNUAL MEETING AND EXPO OF THE AMERICAN OIL CHEMISTS' SOCIETY. 2002.
Technical Abstract: Production of biodiesel, an alternative diesel fuel derived from transesterification of vegetable oils or animal fats with methanol, has grown tremendously in the United States the past two years, from 500,000 gal in 1999 to 25 million gal in 2001. Though the commercial prospects for biodiesel have also grown, there remains some concern with respect to its resistance to oxidative degradation during storage. This work examines the prediction of relative oxidative stability of biodiesel under isothermal conditions utilizing parameters inferred from non- isothermal differential scanning calorimetry (DSC) analyses. Activation energies and Arrhenius constants were inferred from DSC results using the Ozawa-Flynn-Wall method. These parameters were employed to determine oxidation reaction rate constants at 50, 60, 75 and 90C for neat methyl soyate as well as methyl soyate treated tert- butylhydroxyquinone (TBHQ) and alpha-tocopherol antioxidants. Isothermal oxidation induction periods for first- and second-order and autocatalytic reaction kinetics were determined applying rate constants derived from non-isothermal DSC analyses. Induction periods compared well with oil stability index (OSI) measured by AOCS Method Cd 12b-92.