TEMPERATURE-DEPENDENCE OF THE REACTION OF CF3CFCLO2 RADICALS WITH NO AND THE UNIMOLECULAR DECOMPOSITION OF THE CF3CFCLO RADICAL

Absolute rate coefficients for the reaction CF3CFClO2 + NO --> CF3CFCl O + NO2 were determined over the temperature range 273-342 K. CF3CFClO 2 radicals were generated by flash photolysis of CF3CFHCl/O-2/ Cl-2/N- 2 mixtures, and the kinetics were investigated by monitoring the growt h rate of the NO2+ molecular ion by quadrupole mass spectrometry. The temperature dependence of the reaction rate coefficient can be express ed as k = (7.40 +/- 1.42) X e([(274.0+/-32.47)/T]) X 10(-12) s(-1) or k = (1.83 +/- 0.09) X (T/300)(-[0.91+/-0.09)] X 10(-11) cm(3) molecule (-1) s(-1). The rate constant was independent of pressure in the range 10-25 Torr. Measurement of the NO2 yield indicated that the CF3CFClO radical decomposes by Cl atom elimination, CF3CFClO --> CF3CFO + Cl, o n a time scale that is comparable to or shorter than the millisecond o bservation times of these experiments.