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

Abstract

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 (k_het ≤ 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.