title: Mechanism and kinetics of low-temperature oxidation of a biodiesel surrogate: methyl propanoate radicals with oxygen molecule.
abstract: This paper presents a computational study on the low-temperature mechanism and kinetics of the reaction between molecular oxygen and alkyl radicals of methyl propanoate (MP), which plays an important role in low-temperature oxidation and/or autoignition processes of the title fuel. Their multiple reaction pathways either accelerate the oxidation process via chain branching or inhibit it by forming relatively stable products. The potential energy surfaces of the reactions between three primary MP radicals and molecular oxygen, namely, C(•)H2CH2COOCH3 + O2, CH3C(•)HCOOCH3 + O2, and CH3CH2COOC(•)H2 + O2, were constructed using the accurate composite CBS-QB3 method. 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 calculation results are in good agreement with a limited number of scattered data in the literature. Furthermore, pressure- and temperature-dependent rate constants for all reaction channels on the multiwell-multichannel potential energy surfaces were computed with the quantum Rice-Ramsperger-Kassel (QRRK) and the modified strong collision (MSC) theories. This procedure resulted in a thermodynamically consistent detailed kinetic submechanism for low-temperature oxidation governed by the title process. A simplified mechanism, which consists of important reactions, is also suggested for low-temperature combustion at engine-like conditions.
authors.affiliation: †Institute for Computational Science and Technology, Ho Chi Minh City, Vietnam.
authors.forename: Xuan T
authors.initials: XT
authors.lastname: Le
authors.affiliation: †Institute for Computational Science and Technology, Ho Chi Minh City, Vietnam.
authors.forename: Tam V T
authors.initials: TV
authors.lastname: Mai
authors.affiliation: ‡Institute of Chemistry, University of Bialystok, ul Hurtowa 1, 15-399 Białystok, Poland.
authors.forename: Artur
authors.initials: A
authors.lastname: Ratkiewicz
authors.affiliation: †Institute for Computational Science and Technology, Ho Chi Minh City, Vietnam.|§International University, Vietnam National University - HCMC, Linh Trung, Thu Duc District, Ho Chi Minh City, Vietnam.
authors.forename: Lam K
authors.initials: LK
authors.lastname: Huynh
mesh_terms: D005609:Free Radicals / Q000737:chemistry*; D007700:Kinetics; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011422:Propionates / Q000737:chemistry*; D011789:Quantum Theory; D013696:Temperature
chemical_list: D005609:Free Radicals; D011422:Propionates; D010100:Oxygen