Kinetics of chlorine oxide radical reactions using modulated photolysis. Part 4.—The reactions Cl + Cl2O → Cl2+ ClO and ClO + HO2→ products studied at 1 atm and 300c k

Abstract

Rate coefficients for the reactions, HO2+ ClO → HOCl + O2(1a), → HCl + O3(1b), Cl + Cl2O → Cl2+ ClO (2), have been determined by studying the modulated photolysis of mixtures of Cl2, Cl2O, H2, O2 and N2 at 300 K and 1 atm total pressure. HO2 and ClO were observed by u.v. absorption spectroscopy and kinetic information was obtained by monitoring the in-phase and in-quadrature absorption components as a function of photolysis period. The values obtained for k1 and k2 were: k1=(5.4+4–2)× 10–12 cm3 molecule–1 s–1, k2=(1.0±0.35)× 10–10 cm3 molecule–1 s–1. An upper limit for the pathway (1b) was determined by observing the production of ozone in the reaction mixture: k1b⩽ 1.5 × 10–14 cm3 molecule–1 s–1.