Absolute and site-specific abstraction rate coefficients for reactions of Cl with CH3CH2OH, CH3CD2OH, and CD3CH2OB between 295 and 600 K

Absolute rate coefficients for reactions of Cl atoms with selectively deute rated ethanols have been measured between 295 and 600 K by a laser-photolys is/CW infrared absorption method. Yields of HCl are determined by compariso n with the Cl + ethane or Cl + propane reaction, permitting site-specific b ranching fractions to be derived. Smog chamber experiments with Fourier tra nsform infrared (FTIR) detection are performed to determine products of the room-temperature Cl + C2H5OH reaction. The rate coefficients for all ethan ols display only a slight temperature dependence and can be parametrized by simple Arrhenius expressions: k(CH3CH2OH) = (9.4 +/- 1.4) x 10(-11)e((45 /- 32)/T), k(CD3CH2OH) = (6.6 +/- 0.9) x 10(-11)e((90 +/- 40)/T), and k(CH3 CD2OH) = (6.9 +/- 0.7) x 10(-11)e((-76 +/- 40)/T) cm(3) molecule(-1) s(-1) (error bars +/-2 sigma). Combining the results from the present work with l iterature data, we recommend k(CH3CH2OH) = (9.5 +/- 1.9) x 10(-11) cm(3) mo lecule(-1) s(-1) at 298 K. The room-temperature contribution of abstraction at the methyl site is found to be 0.07 +/- 0.02 from FTIR product analysis of the Cl + CH3CH2OH reaction and 0.08 +/- 0.02 from laser photolysis/CW i nfrared absorption measurements (error bars +/-2 sigma). Abstraction of the hydroxyl hydrogen is negligible. A small but significant amount of HCl (up silon = 1) is produced in the Cl + CD3CH2OH and Cl + CH3CH2OH reactions at room temperature.