Abstract
The kinetics and mechanism of the following reactions have been studied in the temperature range 230–360 K and at total pressure of 1 Torr of helium, using the discharge‐flow mass spectrometric method: 1a:
1b:
The following Arrhenius expression for the total rate constant was obtained from the kinetics of OH consumption in excess of ClO radical, produced in the Cl + O~3~ reaction either in excess of Cl atoms or ozone: k~1~ = (6.7 ± 1.8) × 10^−12^ exp {(360 ± 90)/T} cm^3^ molecule^−1^ s^−1^ (with k~1~ = (2.2 ± 0.4) × 10^−11^ cm^3^ molecule^−1^ s^−1^ at T = 298 K), where uncertainties represent 95% confidence limits and include estimated systematic errors. The value of k~1~ is compared with those from previous studies and current recommendations. HCl was detected as a minor product of reaction (1) and the rate constant for the channel forming HCl (reaction (1b)) has been determined from the kinetics of HCl formation at T = 230–320 K: k~1b~ = (9.7 ± 4.1) × 10^−14^ exp{(600 ± 120)/T} cm^3^ molecule^−1^ s^−1^ (with k~1b~ = (7.3 ± 2.2) × 10^−13^ cm^3^ molecule^−1^ s^−1^ and k~1b~/k~1~ = 0.035 ± 0.010 at T = 298 K), where uncertainties represent 95% confidence limits. In addition, the measured kinetic data were used to derive the enthalpy of formation of HO~2~ radicals: Δ H~f,298~(HO~2~) = 3.0 ± 0.4 kcal mol^−1^. © 2001 John Wiley & Sons, Inc. Int J Chem Kinet 33: 587–599, 2001