کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5417307 | 1506910 | 2009 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Theoretical investigation of the hydrogen abstraction from CF3CH2CF3 by OH radicals, F, and Cl atoms: A dual-level direct dynamics study
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The hydrogen abstraction reactions of the CF3CH2CF3 with the OH radicals (R1), F (R2), and Cl (R3) atoms have been studied theoretically over a wide temperature range 200-1000Â K. In this study, the recently developed hybrid density functional theory BB1K is used to obtain reaction path information including the geometries and frequencies of the stationary points. To refine the energies, single-point energy calculations were performed at the BMC-CCSD level using the BB1K geometries. The rate constants are carried out by the canonical variational transition state theory (CVT) with the small-curvature tunneling correction method (SCT). It is found that the activation energies for the title reactions are on the order of R3Â >Â R1Â >Â R2 and the rate constants exhibit just the opposite order, i.e., k2Â >Â k1Â >Â k3. The calculated CVT/SCT rate constants are compared with the available experimental values in the temperature region 269-413Â K. The temperature dependence of the rate constants can be expressed by three-parameter Arrhenius expressions (cm3Â molâ1Â sâ1): k1Â =Â 1.18Â ÃÂ 10â19T2.51 exp(â1761.16/T), k2Â =Â 2.47Â ÃÂ 10â15T1.36 exp(â689.34/T), and k3Â =Â 4.24Â ÃÂ 10â21T3.22 exp(â2819.55/T)Â cm3Â molâ1Â sâ1, respectively. Furthermore, in order to further reveal the thermodynamics properties, the enthalpies of formation of CF3CH2CF3 and CF3CHCF3 are studied using isodesmic reactions.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Molecular Structure: THEOCHEM - Volume 913, Issues 1â3, 15 November 2009, Pages 107-116
Journal: Journal of Molecular Structure: THEOCHEM - Volume 913, Issues 1â3, 15 November 2009, Pages 107-116
نویسندگان
Hong Gao, Ying Wang, Su-Qin Wan, Jing-Yao Liu, Chia-Chung Sun,