Theoretical studies on kinetics,mechanism and thermochemistry of gas-phase reactions of HFE-449mec-f with OH radicals and Cl atom |
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| Affiliation: | 1. Department of Physics, Guizhou University, Guiyang 550025, China;2. College of Computer and Information Engineering, Guizhou MinZu University, Guiyang 550025, China;1. Institute of Environmental and Analytical Sciences, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China;2. Wuhan Center for Magnetic Resonance, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, PR China;1. (L.U.Q.C.A), Laboratorio Universitario de Química y Contaminación del Aire., Instituto de Investigaciones en Fisicoquímica de Córdoba (I.N.F.I.Q.C.), CONICET, Dpto., de Fisicoquímica, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba., Ciudad Universitaria, 5000, Córdoba, Argentina;2. LEA - Laboratorio de Estudios Atmosféricos- INQUINOA (CONICET-UNT), Facultad de Bioquímica, Química y Farmacia, Universidad Nacional de Tucumán, San Lorenzo 456, T4000CAN, San Miguel de Tucumán, Argentina;3. Institute for Atmospheric and Environmental Research, Faculty for Mathematics and Natural Sciences, University of Wuppertal, D-42097, Wuppertal, Germany;1. Department of Physics, Faculty of Science, University of Bamenda, Bambili, P. O. Box 39, Cameroon;2. Department of Physics, Faculty of Science, University of Maroua, Maroua, P. O. Box 814, Cameroon;3. Department of Physics, Higher Teacher''s Training College, University of Maroua, Maroua, P. O. Box 46, Cameroon;4. Department of Physics, Faculty of Science, University of Ngaoundéré, Ngaoundéré, P. O. Box 454, Cameroon;5. Laboratory of Fundamental Physics, Faculty of Science, University of Douala, Douala, P. O. Box, 24157, Cameroon |
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| Abstract: | A theoretical study on the mechanism and kinetics of the gas phase reactions of CF3CHFCF2OCH2CF3 (HFE-449mec-f) with the OH radicals and Cl atom have been performed using meta-hybrid modern density functional M06-2X using 6-31+G(d,p) basis set. Two conformers have been identified for CF3CHFCF2OCH2CF3 and the most stable one is considered for detailed study. Reaction profiles for OH-initiated hydrogen abstraction are modeled including the formation of pre-reactive and post-reactive complexes at entrance and exit channels. Our calculations reveal that hydrogen abstraction from the  CH2 group is thermodynamically and kinetically more facile than that from the CHF group. Using group-balanced isodesmic reactions, the standard enthalpies of formation for HFE-449mecf and radicals generated by hydrogen abstraction, are also reported. The calculated bond dissociation energies for CH bonds are in good agreement with experimental results. The rate constants of the two reactions are determined for the first time in a wide temperature range of 250–450 K. The calculated rate constant values are found to be 9.10 × 10−15 and 4.77 × 10−17 cm3 molecule−1 s−1 for reactions with OH radicals and Cl atom, respectively. At 298 K, the total calculated rate coefficient for reactions with OH radical is in good agreement with the experimental results. The atmospheric life time of HFE-449mec-f is estimated to be 0.287 years. |
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| Keywords: | Hydrofluoroether M06-2X Isodesmic reaction Rate constant Atmospheric lifetime |
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