This Study examines the effect of unsaturation oil the combustion of fatty acid methyl esters (FAME). New experimental results were obtained for the oxidation of methyl (E)-2-butenoate (MC, unsaturated C-4 FAME) and methyl butanoate (MB, saturated C-4 FAME) in I jet-stirred reactor (JSR) at atmospheric pressure Under dilute conditions over the temperature range 850-1400 K, and two equivalence ratios (Phi = 0.375, 0.75) with a residence little of 0.07 s. The results Consist Of concentration profiles of the reactants, stable intermediates, and final products, measured by probe sampling followed by on-line and off-line gas chromatography analyses. The oxidation of MC and MB in the JSR and under counterflow diffusion flame conditions was modeled using a new detailed chemical kinetic reaction mechanism (301 species and 1516 reactions) derived from Previous schemes proposed in the literature. The laminar counterflow flame and JSR (for Phi = 1.13) experimental results used were from I previous Study on the comparison of the combustion of both compounds. Sensitivity analyses and reaction path analyses, based oil rates of reaction, were used to interpret the results. The data and the model show that MC has reaction pathways analogous to that of MB under the present conditions. The model of MC oxidation provides a better understanding of the effect of the ester function oil combustion, and the effect Of unsaturation oil the combustion of fatty acid methyl ester compounds typically found in biodiesel. (C) 2009 The Combustion Institute. Published by Elsevier Inc. All rights reserved.