Kinetics of the ClO + NO2 + M Reaction

Article abstract of DOI:10.1021/j100460a026

The ClO + NO2 + M reaction has been studied with two techniques: Fourier transform infrared spectroscopy of the products, and flash photolysis-ultraviolet absorption to monitor the decay of ClO in excess NO2.The measured third-order rate constant is 1.5E-31 cm⁶ molecule^-2 s^-1 at 298 K with M=N2, in good agreement with previous literature values, but the rate constant appears to decrease by up to a factor of 3 in the presence of increasing amounts of OClO.For the infrared studies a stoichiometric mixture of ClO and NO2 was prepared in a flow system by mixing NO with OClO; at least as much NO2 as ClONO2 was produced under a variety of experimental conditions.These two sets of results are incompatible with the assumption made in previous kinetic studies that ClONO2 is the only recombination product; other isomers such as OClONO or ClOONO are likely to be formed three to four times faster.These results imply that potential stratospheric ozone depletion due to chlorofluoromethanes may be even larger than previously thought.