Rate Constant Calculations of H-Atom Abstraction Reactions from Ethers by H犬2 Radicals
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- 作者：Jorge Mendes ; Chong-Wen Zhou ; Henry J. Curran
- 刊名：Journal of Physical Chemistry A
- 出版年：2014
- 出版时间：February 27, 2014
- 年：2014
- 卷：118
- 期：8
- 页码：1300-1308
- 全文大小：540K
- 年卷期：v.118,no.8(February 27, 2014)
- ISSN：1520-5215
文摘
In this work, we detail hydrogen atom abstraction reactions from six ethers by the hydroperoxyl radical, including dimethyl ether, ethyl methyl ether, propyl methyl ether, isopropyl methyl ether, butyl methyl ether, and isobutyl methyl ether, in order to test the effect of the functional group on the rate constant calculations. The M酶ller鈥揚lesset (MP2) method with the 6-311G(d,p) basis set has been employed in the geometry optimizations and frequency calculations of all of the species involved in the above reaction systems. The connections between each transition state and the corresponding local minima have been determined by intrinsic reaction coordinate calculations. Energies are reported at the CCSD(T)/cc-pVTZ level of theory and include the zero-point energy corrections. As a benchmark in the electronic energy calculations, the CCSD(T)/CBS extrapolation was used for the reactions of dimethyl ether + H犬2 radicals. A systematic calculation of the high-pressure limit rate constants has been performed using conventional transition-state theory, including asymmetric Eckart tunneling corrections, in the temperature range of 500鈥?000 K. The one dimensional hindrance potentials obtained at MP2/6-311G(d,p) for the reactants and transition states have been used to describe the low frequency torsional modes. Herein, we report the calculated individual, average, and total rate constants. A branching ratio analysis for every reaction site has also been performed.