Mechanism and kinetics of low-temperature oxidation of a biodiesel surrogate-methyl acetate radicals with molecular oxygen

作者：Mai Tam V T; Le Xuan T; Huynh Lam K^*

来源：Structural Chemistry, 2015, 26(2): 431-444.

DOI：10.1007/s11224-014-0495-2

• Biodiesel surrogate
• Oxygenated hydrocarbon
• Alkyl peroxy radical
• Detailed kinetic model
• Low-temperature oxidation and ignition

Accurate description of reactions between methyl acetate (MA) radicals and molecular oxygen is an essential prerequisite for understanding as well as modeling low-temperature oxidation and/or ignition of MA, a small biodiesel surrogate, because their multiple reaction pathways either accelerate the oxidation process via chain branching or inhibit it by forming relatively stable products. The accurate composite CBS-QB3 level of theory was used to explore potential energy surfaces for MA radicals + O-2 system. Using the electronic structure calculation results under the framework of canonical statistical mechanics and transition state theory, thermodynamic properties of all species as well as high-pressure rate constants of all reaction channels were derived with explicit corrections for tunneling and hindered internal rotations. Our calculated results are in good agreement with a limited number of scattered data in the literature. Furthermore, pressure- and temperature-dependent rate constants were then computed using the Quantum Rice-Ramsperger-Kassel and the modified strong collision theories. This procedure resulted in a thermodynamically consistent detailed kinetic mechanism for low-temperature oxidation of the title fuel. We also demonstrated that even the detailed mechanism consists of several reactions of different reaction types, only the addition of the reactants and the re-dissociation of the initially formed adducts are important for low-temperature combustion at engine-liked conditions.

• 出版日期2015-4