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Mechanism and kinetic studies for OH radical-initiated atmospheric oxidation of methyl propionate
Abstract DFT molecular orbital theory calculations were carried out to investigate OH radical-initiated atmospheric oxidation of methyl propionate. Geometry optimizations of the reactants as well as the intermediates, transition states and products were performed at the B3LYP/6-31G(d,p) level. As the electron correlation and basis set effect, the single-point energies were computed by using various levels of theory, including second-order Møller–Plesset perturbation theory (MP2) and the coupled-cluster theory with single and double excitations including perturbative corrections for the triple excitations (CCSD(T)). The detailed oxidation mechanism is presented and discussed. The results indicate that the formation of 3-oxo-methyl propionate (HC(O)CH2C(O)OCH3) is thermodynamically feasible and the isomerization of alkoxy radical IM17 (CH3CH(O)C(O)OCH3) can occur readily under the general atmospheric conditions. Canonical variational transition-state (CVT) theory with small curvature tunneling (SCT) contribution was used to predict the rate constants. The overall rate constants were determined, k(T)(CH3CH2COOCH3 + OH) = (1.35 × 10−12)exp(−174.19/T) cm3 molecule−1 s−1, over the possible atmospheric temperature range of 180–370 K.
Highlights ► Mechanism and kinetics for OH-initiated reaction of methyl propionate were studied. ► Detailed reaction mechanism was proposed. ► The overall rate constant have been obtained. ► The atmospheric lifetime determined by OH radicals is about 15.5 days.
Mechanism and kinetic studies for OH radical-initiated atmospheric oxidation of methyl propionate
Abstract DFT molecular orbital theory calculations were carried out to investigate OH radical-initiated atmospheric oxidation of methyl propionate. Geometry optimizations of the reactants as well as the intermediates, transition states and products were performed at the B3LYP/6-31G(d,p) level. As the electron correlation and basis set effect, the single-point energies were computed by using various levels of theory, including second-order Møller–Plesset perturbation theory (MP2) and the coupled-cluster theory with single and double excitations including perturbative corrections for the triple excitations (CCSD(T)). The detailed oxidation mechanism is presented and discussed. The results indicate that the formation of 3-oxo-methyl propionate (HC(O)CH2C(O)OCH3) is thermodynamically feasible and the isomerization of alkoxy radical IM17 (CH3CH(O)C(O)OCH3) can occur readily under the general atmospheric conditions. Canonical variational transition-state (CVT) theory with small curvature tunneling (SCT) contribution was used to predict the rate constants. The overall rate constants were determined, k(T)(CH3CH2COOCH3 + OH) = (1.35 × 10−12)exp(−174.19/T) cm3 molecule−1 s−1, over the possible atmospheric temperature range of 180–370 K.
Highlights ► Mechanism and kinetics for OH-initiated reaction of methyl propionate were studied. ► Detailed reaction mechanism was proposed. ► The overall rate constant have been obtained. ► The atmospheric lifetime determined by OH radicals is about 15.5 days.
Mechanism and kinetic studies for OH radical-initiated atmospheric oxidation of methyl propionate
Sun, Xiaoyan (Autor:in) / Hu, Yueming (Autor:in) / Xu, Fei (Autor:in) / Zhang, Qingzhu (Autor:in) / Wang, Wenxing (Autor:in)
Atmospheric Environment ; 63 ; 14-21
21.08.2012
8 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Atmospheric oxidation mechanism of acenaphthene initiated by OH radicals
| Elsevier | 2020