Reaction of Oxygen Atoms with Chlorine

The reaction between O(3P) atoms and Cl2 has been studied in a fast flow reactor coupled to a time-of-flight mass spectrometer. The reaction is first order in O and Cl2 and can be described by the mechanism, O+Cl2=OCl+Cl,O+ClO=Cl+O2.The rate constant for Reaction (1) is (7.5±0.6) × 10−14 cc molecule−1·sec−1 at 300°K. In the Cl2-rich system, the over-all rate constant is twice this value indicating that Reaction (2) is much faster than Reaction (1). A lower limit has been obtained for the rate constant of Reaction (2) of 10−11 cc molecule−1·sec−1. The apparent gas-phase catalytic effect of Cl2 for the recombination of O atoms previously reported has been shown to be incorrect and to arise from a rapid regeneration of Cl2 molecules on HF ``poisoned'' walls.