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Theoretical study and rate constant calculation for reaction of CF 3 CH 2 OH with OH
Author(s) -
Wang Ying,
Liu JingYao,
Li ZeSheng,
Wang Li,
Sun ChiaChung
Publication year - 2007
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.20592
Subject(s) - methylene , chemistry , reaction rate constant , isodesmic reaction , transition state theory , computational chemistry , potential energy surface , abstraction , thermodynamics , transition state , kinetics , ab initio , density functional theory , medicinal chemistry , physics , quantum mechanics , organic chemistry , philosophy , catalysis , epistemology
The reaction mechanism of CF 3 CH 2 OH with OH is investigated theoretically and the rate constants are calculated by direct dynamics method. The potential energy surface (PES) information, which is necessary for dynamics calculation, is obtained at the B3LYP/6‐311G (d, p) level. The single‐point energy calculations are performed at the MC‐QCISD level using the B3LYP geometries. Complexes, with the energies being less than corresponding reactants and products, are found at the entrance and exit channels for methylene‐H‐abstraction channel, while for the hydroxyl‐H‐abstraction channel only entrance complex is located. By means of isodesmic reactions, the enthalpies of the formation for the species CF 3 CH 2 OH, CF 3 CHOH, and CF 3 CH 2 O are estimated at the MC‐QCISD//B3LYP/6‐311G (d, p) level of theory. The rate constants for two kinds of H‐abstraction channels are evaluated by canonical variational transition state theory with the small‐curvature tunneling correction (CVT/SCT) over a wide range of temperature 200–2000 K. The calculated results are in good agreement with the experimental values in the temperature region 250–430 K. The present results indicate that the two channels are competitive. Below 289 K, hydroxyl‐H‐abstraction channel has more contribution to the total rate constants than methylene‐H‐abstraction channel, while above 289 K, methylene‐H‐abstraction channel becomes more important and then becomes the major reaction channel. © 2007 Wiley Periodicals, Inc. J Comput Chem 28: 802–810, 2007