Measuring the rate constant of the reaction between chlorine atoms and CHF2Br by Cl atom resonance fluorescence

The rate constant of the reaction between Cl atoms and CHF2Br has been measured by chlorine atom resonance fluorescence in a flow reactor at temperatures of 295–368 K and a pressure of ~1.5 Torr. Lining the inner surface of the reactor with F-32L fluoroplastic makes the rate of the heterogeneous loss of chlorine atoms very low (khet ≤ 5 s–1). The rate constant of the reaction is given by the formula k = (4.23 ± 0.13) × 10–12e(–15.56 ± 1.58)/RT cm3 molecule–1 s–1 (with the activation energy in kJ/mol units). The possible role of this reaction in the extinguishing of fires producing high concentrations of chlorine atoms is discussed.