Journal of Physical Chemistry A, Vol.102, No.7, 1152-1161, 1998
Atmospheric chemistry of CF3CH2OCH2CF3 : UV spectra and kinetic data for CF3CH(center dot)OCH2CF3 and CF3CH(OO center dot)OCH2CF3 radicals and atmospheric fate of CF3CH(O center dot)OCH2CF3 radicals
Pulse radiolysis transient UV absorption spectroscopy was used to study the ultraviolet absorption spectra (220-320 nm) and kinetics of CF3CH(.)OCH2CF3 and CF3CH(OO .)OCH2CF3 radicals at 296 K, At 230 nm sigma(CF3CH(.)OCH2CF3) = (1.95 +/- 0.24) x 10(-18) and sigma(CF3CH(OO .)OCH2CF3) = (4.40 +/- 0.51) x 10(-18) cm(2) molecule(-1), Rate constants for the reaction of F atoms with CF3CH2OCH2CF3, the self-reactions of CF3CH(.)OCH2CF3 and CF3CH(OO .)OCH2CF3 radicals, the association reaction of CF3CH(.)OCH2CF3 radicals with O-2, and the reactions of CF3CH(OO .)OCH2CF3 radicals with NO and NO2 were (1.5 +/- 0.7) x 10(-11), (2.6 +/- 0.4) x 10(-11), (5.4 +/-0.7) x 10(-12) (uncorrected for possible secondary chemistry), (2.3 +/- 0.3) x 10(-12), (1.45 +/- 0.4) x 10(-11), and (8.4 +/-0.8) x 10(-12) cm(3) molecule(-1) s(-1), respectively. Using an FTIR technique, rate constants for the reaction of Cl atoms with CF3CH2OCH2CF3 and CF3C(O)OCH2CF3 were determined to be (7.1 +/- 0.9) x 10(-13) and (9.4 +/- 1.3) x 10(-16) cm(3) molecule(-1) s(-1). Finally, it was determined that the atmospheric fate of CF3CH(O .)OCH2CF3 radicals is decomposition via C-C bond scission to give CS radicals and 2,2,2-trifluoroethyl formate (CF3CH2OCHO) which occurs at a rate of approximately 7 x 10(5) s(-1). The results are discussed with respect to the atmospheric chemistry of CF3CH2OCH2CF3 and analogous compounds.
Keywords:GAS-PHASE;PEROXY-RADICALS;FLUORINE-ATOMS;CHLORINE ATOMS;NO;295-K;SPECTROSCOPY;CF3CHCL2;CF2CLCH3;CHF2CH3