| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4438592 | Atmospheric Environment | 2012 | 8 Pages |
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.
► 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.
