Computational Studies on the Mechanism and Kinetics of Cl Reaction with C2H5I

The dual-level direct kinetics method has been used to investigate the multichannel reactions of C2H5I + Cl. Three hydrogen abstraction channels and one displacement process are found for the title reaction. The calculation indicates that the hydrogen abstraction from -CH2- group is the dominant reaction channel, and the displacement process may be negligible because of the high barrier. The rate constants for individual reaction channels are calculated by the improved canonical variational transition-state theory with small-curvature tunneling correction over the temperature range of 220-1500 K. Our results show that the tunneling correction plays an important role in the rate constant calculation in the low-temperature range. Agreement between the calculated and experimental data available is good. The Arrhenius expression k(T) = 2.33 x 10(-16) T-1.83 exp(-185.01/T) over a wide temperature range is obtained. Furthermore, the kinetic isotope effects for the reaction C2H5I + Cl are estimated so as to provide theoretical estimation for future laboratory investigation. (C) 2010 Wiley Periodicals, Inc. J Comput Chem 31: 2263-2272, 2010