Temperature Dependence of the Reaction of Chlorine Atoms with CHOH and CHCHO.

Rate constants of the reactions Cl + CHOH → CHOH + HCl ( k) and Cl + CHCHO → CHC(O) + HCl ( k) were measured at 100 Torr over the temperature range 230.3-297.1 K. Radical chemistry was initiated by pulsed laser photolysis of Cl in mixtures of CHOH and CHCHO in a flow reactor. Heterodyne near-IR wavelength modulation spectroscopy was used to directly detect HO produced from the subsequent reaction of CHOH with O in real time to determine the rate of reaction of Cl with CHOH. The rate of Cl + CHCHO was measured relative to that of the Cl + CHOH reaction. Secondary chemistry, including that of the adducts HO·CHOH and HO·CHCHO, was taken into account. The Arrhenius expressions were found to be k( T) = 5.02 × 10 exp[(20 ± 88)/ T] cm molecule s and k( T) = 6.38 × 10 exp[(56 ± 90)/ T] cm molecule s (2σ uncertainties). The average values of the rate constants over this temperature range were k = (5.45 ± 0.37) × 10 cm molecule s and k = (8.00 ± 1.27) × 10 cm molecule s (2σ uncertainties), consistent with current literature values.