Journal of Physical Chemistry, Vol.98, No.34, 8574-8579, 1994
Temperature-Dependence of the Gas-Phase Reactions of Cf3O with CH4 and No
A temperature-regulated flow tube reactor coupled to a chemical ionization mass spectrometer (CIMS) was used to investigate reactions of CF3O with CH4 and NO. The reaction rate constant for the CF3O + CH4 reaction was measured in the temperature range 231-385 K and found to be k(3)(T) = (3.1 +/- 0.5) x 10(-12) exp[(-1470 +/- 250) K/T]cm(3) molecule(-1) s(-1), with k(3)(298 K) = (2.2 +/- 0.4) X 10(-14) cm(3) molecule(-1) s(-1) (where the uncertainties represent our estimated accuracy at the 95% confidence level). The latter is in good agreement with recently reported measurements at room temperature. The reaction rate constant for the CF3O + NO reaction was measured in the temperature range 231-393 K and found to be k(4)(T) = (4.1 +/- 0.6) X 10(-11) exp[(60 +/- 100)K/T], with k(4)(298 K) = (5.0 +/- 1.0) x 10(-11) cm(3) molecule(-1) s(-1). The value at room temperature disagrees with two previously reported values by a factor of about 2.5 but is in good agreement with three recently reported values. The results reported in this study are important in establishing the fate of the CF3Ox, radicals produced as degradation products from hydrofluorocarbons (HFC’s) in the atmosphere.
Keywords:RATE CONSTANTS;KINETICS;RADICALS;HYDROCHLOROFLUOROCARBONS;HYDROFLUOROCARBONS;CHEMISTRY;HFC-134A;PRODUCTS;295-K