Flash photolysis-time-resolved UV spectroscopy of the 1,2,2,2-tetrafluoroethylperoxy radical self-reaction
作者:M. Matti Maricq、Joseph J. Szente
DOI:10.1021/j100205a048
日期:1992.12
The self-reaction of CF3CFHO2 has been studied via time-resolved ultraviolet spectroscopy over the temperature range 211-372 K. The absorption spectrum of CF3CFHO2 extends from 190 to 275 nm with a maximum cross section of (5.2 +/- 0.3) x 10(-18) cm2 molecule-1 at 213 nm. The UV absorbance of the reaction mixture decreases and shifts to the blue as the reaction progresses. This is consistent with the CF3CFHO2 self-reaction producing CF3CFHO, the alkoxy radical then decomposing to yield CF3, which adds molecular oxygen to form CF3O2. The CF3CFHO2 self-reaction has a negative temperature dependence with rate constant given by k1 = (7.8 +/- 1.3) X 10(-13)e(605+/-40)/T cm3 s-1. The rate of alkoxy radical dissociation, at 230 Torr of total pressure, is k2a = (3.7 +/- 0.7) X 10(7)e-(2200+/-150)/T s-1 . The rate constants for CF3O2 reaction with CF3CFHO2 and itself are determined to be k8 = (8 +/- 3) x 10(-12) and k9 = (1.8 +/- 0.5) x 10(-12) cm3 s-1, respectively, at 297 K.