Experimental and Modeling Study of Methyl <i>trans</i>-3-Hexenoate Autoignition

This work presents the results of an experimental and computational study of methyl <i>trans</i>-3-hexenoate autoignition. Experimental autoignition studies were conducted using the University of Michigan rapid compression facility. Pressure time histories were used to determine ignition delay times as a function of test gas composition and experimental conditions. The fuel/oxygen equivalence ratio and dilution level were ϕ = 0.3 and inert/O<sub>2</sub> = 3.76 (mole basis). End of compression conditions targeted an average pressure of 10.5 atm and temperatures ranging from 884 to 1085 K. A correlation in Arrhenius form was developed by regression analysis of the experimental data, where the ignition delay time is τ<sub>ign</sub> (ms) = 1.4 × 10<sup>–6</sup> exp­[30 100/(<i>R̅</i><sub>(cal mol<sup>–1</sup> K<sup>–1</sup>)</sub><i>T</i>)] with a <i>R</i><sup>2</sup> value of 0.99. Gas-sampling experiments were also conducted to measure stable intermediates formed during autoignition. A detailed reaction mechanism was developed and model predictions were compared to the experimental data. While ignition delay time predictions are in excellent agreement with the experimental data, the speciation results highlight uncertainties in the reaction chemistry of unsaturated esters and small hydrocarbon intermediates.