On the kinetic mechanism of the hydrogen abstraction reactions of the hydroxyl radical with CH3CF2Cl and CH3CFCl2: A dual level direct dynamics study |
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| Authors: | Yue‐Meng Ji Fenglei Cao Hui Gao Xiangzhi Li Cunyuan Zhao Chengyong Su Jing‐Yao Liu Ze‐Sheng Li |
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| Institution: | 1. MOE Laboratory of Bioinorganic and Synthetic Chemistry, Sun Yat‐Sen University, Guangzhou 510275, People's Republic of China;2. School of Chemistry and Chemical Engineering, Sun Yat‐Sen University, Guangzhou 510275, People's Republic of China;3. State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130023, People's Republic of China |
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| Abstract: | By means of the dual‐level direct dynamics method, the mechanisms of the reactions, CH3CF2Cl + OH → products (R1) and CH3CFCl2 + OH → products (R2), are studied over a wide temperature range 200–2000 K. The optimized geometries and frequencies of the stationary points are calculated at the MP2/6‐311G(d,p) level, and then the energy profiles of the reactions are refined with the interpolated single‐point energy method at the G3(MP2) level. The canonical variational transition‐state theory with the small‐curvature tunneling (SCT) correction method is used to calculate the rate constants. For the title reactions, three reaction channels are identified and the H‐abstraction channel is the major pathway. The results indicate that F substitution has a significant (reductive) effect on hydrochlorofluorocarbon reactivity. Also, for all H‐abstraction reaction channels the variational effect is small and the SCT effect is only important in the lower temperature range on the rate constants calculation. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2010 |
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| Keywords: | ab initio calculations computer chemistry gas‐phase reactions kinetics |
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