Kinetics of the reactions of the hydroxyl radical with CH3OH and C2H5OH between 235 and 360 K

The kinetics of the reaction of the hydroxyl radical (OH) with methanol (1, rate coefficient k1) and ethanol (2, rate coefficient k2), has been studied as a function of temperature (T=235–360 K and T=227–360 K, respectively) by using laser photolysis of a suitable OH-precursor to generate OH and laser-induced fluorescence to detect it. The rate coefficients for reactions (1) and (2) are given by the following expressions (in cm3 molecule −1 s−1): k1(T)=(3.6±0.8)×10−12 exp(−(415±70)/T) and k2(T)=(4.3±0.7)×10−12 exp(−(85±35)/T), respectively, where the uncertainties include the precision of the fit to the Arrhenius expression and estimated systematic errors (±2σ). Our results are consistent with H-atom abstraction taking place primarily at the methyl site of methanol and at the methylene site for ethanol. The atmospheric implications of these reactions are also discussed.