Kinetics of the Reaction of Chlorine Atoms with Vinyl Bromide and Its Use for Measuring Chlorine-Atom Concentrations

Article abstract of DOI:10.1021/j100233a032

The reaction of chlorine atoms with vinyl bromide, Cl + C2H3Br = C2H3Cl + Br, has been tested as a titration reaction for chlorine atoms in gas-phase fast-flow reactors using both continuous and pulsed atom sources.The vinyl chloride produced by this reaction was determined by using photoionization mass spectrometry and was found to be an accurate measure of the in situ chlorine-atom concentration down to 5 * 10¹⁰ atoms cm^-3.The reaction is rapid and stoichiometric and involves the use of easily handled substances.It is particularly well suited for use with photoionization mass spectrometer detectors because of the low ionizaton potentials and high photoionization cross sections of both vinyl bromide and vinyl chloride.The rate constant of this reaction was measured at 298 K and determined to be 1.43 (+/- 0.29) * 10^-10 cm³ molecule^-1 s^-1.