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Theoretical studies of the reactions of CF 3 CHCLOCHF 2 /CF 3 CHFOCHF 2 with OH radical and Cl atom and their product radicals with OH
Author(s) -
Yang Lei,
Liu JingYao,
Wan SuQin,
Li ZeSheng
Publication year - 2009
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.21079
Subject(s) - chemistry , radical , reaction rate constant , arrhenius equation , transition state theory , reactivity (psychology) , activation energy , branching (polymer chemistry) , computational chemistry , kinetics , physics , organic chemistry , medicine , alternative medicine , pathology , quantum mechanics
The mechanisms and dynamics studies of the OH radical and Cl atom with CF 3 CHClOCHF 2 and CF 3 CHFOCHF 2 have been carried out theoretically. The geometries and frequencies of all the stationary points are optimized at the B3LYP/6‐311G(d,p) level, and the energy profiles are further refined by interpolated single‐point energies (ISPE) method at the G3(MP2) level of theory. For each reaction, two H‐abstraction channels are found and four products (CF 3 CHFOCF 2 , CF 3 CFOCHF 2 , and CF 3 CHClOCF 2 , CF 3 CClOCHF 2 ) are produced during the above processes. The rate constants for the CF 3 CHClOCHF 2 /CF 3 CHFOCHF 2 + OH/Cl reactions are calculated by canonical variational transition‐state theory (CVT) within 200–2000 K, and the small‐curvature tunneling is included. The total rate constants calculated from the sum of the individual rate constants and the branching ratios are in good agreement with the experimental data. The Arrhenius expressions for the reactions are obtained. Our calculation shows that the substitution of Cl by F decreases the reactivity of CF 3 CHClOCHF 2 toward OH and Cl. In addition, the mechanisms of subsequent reactions of product radicals and OH radical are further investigated at the G3(MP2)//B3LYP/6‐311G(d,p) level, and the main products are predicted in the this article. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009