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Theoretical study on the rate constants for the C 2 H 5 + HBr → C 2 H 6 + Br reaction
Author(s) -
Sheng Li,
Li ZeSheng,
Liu JingYao,
Xiao JingFa,
Sun ChiaChung
Publication year - 2004
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.10388
Subject(s) - chemistry , kinetic isotope effect , reaction rate constant , atmospheric temperature range , kinetic energy , negative temperature , inverse , hydrobromic acid , thermodynamics , computational chemistry , atomic physics , analytical chemistry (journal) , kinetics , deuterium , physics , inorganic chemistry , geometry , mathematics , quantum mechanics , chromatography
The reaction C 2 H 5 + HBr → C 2 H 6 + Br has been theoretically studied over the temperature range from 200 to 1400 K. The electronic structure information is calculated at the BHLYP/6‐311+G(d,p) and QCISD/6‐31+G(d) levels. With the aid of intrinsic reaction coordinate theory, the minimum energy paths (MEPs) are obtained at the both levels, and the energies along the MEP are further refined by performing the single‐point calculations at the PMP4(SDTQ)/6‐311+G(3df,2p)//BHLYP and QCISD(T)/6‐311++G(2df,2pd)//QCISD levels. The calculated ICVT/SCT rate constants are in good agreement with available experimental values, and the calculate results further indicate that the C 2 H 5 + HBr reaction has negative temperature dependence at T < 850 K, but clearly shows positive temperature dependence at T > 850 K. The current work predicts that the kinetic isotope effect for the title reaction is inverse in the temperature range from 200 to 482 K, i.e., k HBr / k DBr < 1. © 2003 Wiley Periodicals, Inc. J Comput Chem 25: 423–428, 2004