Journal of Physical Chemistry, Vol.100, No.16, 6572-6579, 1996
Atmospheric Chemistry of Hfc-227Ca - Spectrokinetic Investigation of the Cf3Cf2Cf2O2 Radical, Its Reactions with No and NO2, and the Atmospheric Fate of the Cf3Cf2Cf2O Radical
A pulse radiolysis technique was used to study the UV absorption spectrum of CF3CF2CF2O2 radicals, at 230 nm sigma = (3.2 +/- 0.4) x 10(-18) cm(2) molecule(-1). Rate constants for reactions of CF3CF2CF2O2 radicals with NO and NO2 were k(3) > 7 x 10(-12) cm(3) molecule(-1) s(-1) and k(4) = (7.6 +/- 2.4) x 10(-12) cm(3) molecule(-1) s(-1), respectively. The rate constant for reaction of F atoms with CF3CF2CF2H was determined by using an absolute rate technique to be (3.6 +/- 1.3) x 10(-13) cm(3) molecule(-1) s(-1). The atmospheric fate of CF3CF2CF2O radicals is decomposition via C-C bond scission to give CF3CF2 radicals and CF2O. In one bar of SF6 at 296 K, into CF3CF2O radicals which also decompose via C-C bond scission. As part of this work a relative rate method was used to measure k(Cl + CF3CF2CF2H) = (3.4 +/- 0.7) x 10(-16) and k(F + CF3CF2CF2H) = (3.2 +/- 0.8) x 10(-13) cm(3) molecule(-1) s(-1). The results are discussed with respect to the atmospheric chemistry of HFC-227ca.
Keywords:GAS-PHASE;PEROXY-RADICALS;CF3CH2F;CHF2CH3;295-K;SPECTROSCOPY;CF2CLCH3;KINETICS;HFC-134A;ATOMS