Rate constants for the reaction of OH + CO, OD + CO, and OH + methane as a function of temperature

The temperature dependence of the reactions of OH + CO, OD + CO, and OH + methane has been measured from 340 to 1250 K in the presence of 1 atm of argon and 15 torr of water vapor. The OH + methane measurements are in excellent agreement with previous studies. The rate constants for OH + CO are in excellent agreement with previous results over the range of 500-1000 K; at lower temperatures the rates measured are faster than earlier results. This is probably due to higher water concentrations used in these experiments. Above 1000 K, the rates determined by this work are considerably faster than those previously determined. Previous experiments at higher temperatures are much less direct than the technique used in this work. The agreement between the OD + CO is good at low temperatures; however, there appears to be no high-temperature results to which we can compare these results. The OH + CO results may be described by 4.05 x 10-14 exp(667/T) + 3.04 x 10-9 exp(-3801/T) and the OD + CO results by 1.27 x 10-14 exp(455/T) + 2.33 x 10-10 exp(-5668/T). The OH + CH4 data may be described by 3.7 x 10-11 exp (-2550/T). 31 references, 6 figures