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 = (3.4-2.5+1.7) × 10-10 cm3 molecule-1 s-1.