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: k_1b⩽ 1.5 × 10^–14 cm³ molecule^–1 s^–1.