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 k(1)) and ethanol (2, rate coefficient k(2)), 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 cm(3) molecule(-1) s(-1)): k(1) (T)=(3.6+/-0.8)x10(-12) exp(-(415+/-70)/T) and k(2)(T)=(4.3+/-0.7)x10(-12) exp(-(85+/-35)/T), respectively, where the uncertainties include the precision of the fit to the Arrhenius expression and estimated systematic errors (+/-2sigma). 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. (C) 2003 Elsevier Science B.V. All rights reserved.