Direct Dynamics Study on the Mechanism and the Kinetics of the Reaction of CH3NH2 With OH

作者：Tian Wei; Wang Wenliang^*; Zhang Yue; Wang Weina

来源：International Journal of Quantum Chemistry, 2009, 109(7): 1566-1575.

DOI：10.1002/qua.22000

• methylamine
• direct dynamics
• mechanism
• rate constant
• transition state

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 CH2NH2 and H2O via hydrogen abstraction from the CH3 group of CH3NH2 by OH in the calculated temperature range.

• 出版日期2009-6
• 单位陕西师范大学