| Abstract
| - Using FTIR smog chamber techniques, k(Cl + CF3OCF2CF2H) = (2.70 ± 0.52) × 10-16, k(OH + CF3OCF2CF2H) = (2.26 ± 0.18) × 10-15, k(Cl + CF3OC(CF3)2H) = (1.58 ± 0.27) × 10-18 and k(OH + CF3OC(CF3)2H) = (3.26 ± 0.95) × 10-16 cm3 molecule-1 s-1 were measured. The atmospheric lifetimes ofCF3OCF2CF2H and CF3OC(CF3)2H are estimated to be 27 and 216 years, respectively. Chlorine atom initiatedoxidation of CF3OCF2CF2H in 700 Torr of air in the presence of NOx gives CF3OC(O)F in a molar yield of36 ± 5% and COF2 in a molar yield of 174 ± 9%, whereas oxidation of CF3OC(CF3)2H gives CF3OC(O)CF3and COF2 in molar yields that are indistinguishable from 100%. Quantitative infrared spectra were recordedand used to estimate global warming potentials of 3690 and 8230 (100 year time horizon, relative to CO2) forCF3OCF2CF2H and CF3OC(CF3)2H, respectively. All experiments were performed in 700 Torr of N2/O2 diluentat 296 ± 2 K. An empirical relationship can be used to estimate the preexponential factor, which can becombined with k(298 K) to give the temperature dependence of reactions of OH radicals with organiccompounds proceeding via H-atom abstraction: log(A/n) = (0.239 ± 0.027) log(k(OH)/n) − (8.69 ± 0.372),k(OH) is the rate constant at 298 K and n is the number of H atoms. The rates of H-atom abstraction by OHradicals and Cl atoms at 298 K from organic compounds are related by the expression log(k(OH)) = (0.412± 0.049) log(k(Cl)) − (8.16 ± 0.72). The utility of these expressions and the atmospheric chemistry of thetitle hydrofluoroethers are discussed.
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