Absolute rate constants for the reaction of fluorine atoms with H2, CH2Cl2, CH2ClF, CH2F2 and CHCl2

Abstract

The rapid reaction F + Br → BrF + Br has been used, with detection of BrF by laser-induced fluorescence, as a monitor of F-atom concentrations in a discharge-flow experiment. Absolute rate constants for the hydrogen-abstraction reactions F + H₂, CH₂Cl₂, CH₂ClF and CH₂F₂ were measured to be k²⁹⁸=(2.6 ± 0.1)× 10^–11, (8.9 ± 0.6)× 10^–12, (7.8 ± 0.4)× 10^–12 and (5.7 ± 0.3)× 10^–12 cm³ molecule^–1 s^–1, respectively. (The errors given are 1σ; a further 10–15% should be added to account for systematic errors.) The reaction of F with CHCl₂ was modelled to give k²⁹⁸=(3.4^+1.7_–2.5)× 10^–10 cm³ molecule^–1 s^–1.