Acta Phys. -Chim. Sin. ›› 2008, Vol. 24 ›› Issue (04): 587-594.doi: 10.3866/PKU.WHXB20080408

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Reaction Mechanism and Kinetics for the Reaction of ·OH+CH3CN

TIAN Yan; HE Tian-Jing; CHEN Dong-Ming; LIU Fan-Chen   

  1. Department of Chemical Physics, University of Science and Technology of China, Hefei 230026, P. R. China; School of Science, Anhui Agricultural University, Hefei 230036, P. R. China
  • Received:2007-11-22 Revised:2008-01-30 Published:2008-04-07
  • Contact: HE Tian-Jing

Abstract: The complex potential energy surface for the reaction of·OH radical with CH3CN, including 2 intermediate complexes, 9 transition states, was theoretically probed at the CBS-QB3 level. The geometries and relative energies for various stationary points were determined. Based on the calculated CBS-QB3 potential energy surface, the possible reaction mechanism of·OH+CH3CN was proposed. The calculated results demonstrated that the formation of P1 (·CH2CN+H2O) was the dominant reaction channel. The rate constant (k1, cm3·molecule-1·s-1) of P1 was calculated by TS theory. Over the temperature range 250-3000 K, we predicted that the expression of k1 was k1(250-3000 K)=2.06×10-20T3.045exp(-780.00/T). By comparing with the obtained experimental values it was shown that the values of k1 were in good agreement with the experimental results over the temperature range 250-320 K. The calculated results indicated the formation of P1 (CH3CN+·OH) only needed a barrier of 14.2 kJ·mol-1. While the products ·CH2CN+H2O retrograded to the reactants CH3CN+·OH, an energy barrier of 111.2 kJ·mol-1 was required. These results suggested that the backward direction for the pathway of formation product P1 would be difficult in the ground electronic state.

Key words: ·OH radical, CH3CN, Reaction mechanism, CBS-QB3


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