Hydrogen-atom abstraction from alkanes by OH. 2. Ethane

Absolute rate coefficients for the reactions of OH with C2H6 (k1), C2H3D3 (k2), and C2D6 (k3) were measured with the laser photolysis/laser-induced fluorescence technique. Kinetic data were obtained at 600 torr of helium pressure over the temperature range 292.5-705 K. The measurements were fit to modified Arrhenius expressions of the form k/sub i/(T) = A/sub i/T/sup n/sub i// exp(-E/sub i//RT). Kinetic isotope effects were characterized by two simple relations: k2(T) = 0.5[k1(T) + k3(T)], and k1(T) = (1.01 +/- 0.06) exp(907 +/- 52 cal mol-1/RT), where the quoted uncertainties represent +/- 2sigma estimates of the total experimental error. Nonempirical electronic structure calculations were performed on the reactants and transition-state structures. They are consistent with and support the experimental findings. 47 references, 8 figures, 4 tables