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Direct dynamics study on the mechanism and the kinetics of the reaction of CH 3 NH 2 with OH
Author(s) -
Tian Wei,
Wang Wenliang,
Zhang Yue,
Wang Weina
Publication year - 2009
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.22000
Subject(s) - chemistry , reaction rate constant , hydrogen atom abstraction , arrhenius equation , transition state theory , thermodynamics , kinetics , methylamine , atmospheric temperature range , hydrogen , computational chemistry , hydrogen atom , activation energy , physics , organic chemistry , quantum mechanics , group (periodic table)
A theoretical study of the mechanism and the kinetics for the hydrogen abstraction reaction of methylamine by OH radical has been presented at the CCSD(T)/6‐311 ++G(2d,2p)//CCSD/6‐31G(d) level of theory. Our theoretical calculations suggest a stepwise mechanism involving the formation of a prereactant complex in the entrance channel and a preproduct complex in the exit channel, for the two hydrogen abstraction channels involving the methyl and amine groups. For clarity, the diagram of potential for the reaction is given. The calculated standard reaction enthalpies are −98.48 and −76.50 kJ mol −1 and barrier heights are 0.36 and 25.25 kJ mol −1 , respectively. The rate constants are evaluated by means of the improved canonical variational transition state theory with small‐curvature tunneling correction (ICVT/SCT) in the temperature range of 299–3000 K. The calculated results show that the rate constants at experimentally measured temperatures are in good agreement with the experimental values. It is shown that the calculated rate constants exhibit a non‐Arrhenius behavior. Moreover, the variational effect is obvious in the calculated temperature range. The dominant product channel is to form CH 2 NH 2 and H 2 O via hydrogen abstraction from the CH 3 group of CH 3 NH 2 by OH in the calculated temperature range. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009