ATMOSPHERIC CHEMISTRY OF HFE-7100 (C4F9OCH3) - REACTION WITH OH RADICALS, UV SPECTRA AND KINETIC DATA FOR C4F9OCH2-CENTER-DOT AND C4F9CH2O2-CENTER-DOT RADICALS, AND THE ATMOSPHERIC FATE OF C4F9OCH2O-CENTER-DOTRADICALS

Relative rate techniques were used to estimate k(OHS-HFE-7100) approxi mate to 1.2 x 10(-14) cm(3) molecule(-1) s(-1) at 295 K leading to an estimate of approximate to 5 years for the atmospheric lifetime of HFE -7100 (HFE = hydrofluoroether). Pulse radiolysis transient UV absorpti on spectroscopy was used to study the ultraviolet absorption spectra a nd kinetics of C4F9OCH2 and C4F9OCH2O2 radicals at 296 K. At 300 nm si gma(C4F9OCH2) = (5.80 +/- 0.76) x 10(-19) and at 250 nm sigma(C4F9OCH2 O2) = (2.24 +/- 0.24) x 10(-18) cm(2) molecule(-1). Both UV spectra sh owed two absorption maxima, one below 230 nm and one at 290 nm. Rate c onstants for the self-reactions of C4F9OCH2 and C4F9OCH2O2 radicals, t he reaction of C4F9OCH2 radicals with O-2, and the reactions of C4F9OC H2O2 radicals with NO and NO2 were (3.5 +/- 0.8) x 10(-11), (1.35 +/- 0.17) x 10(-11) (uncorrected for possible secondary chemistry), (2.5 /- 0.5) x 10(-12), (8.5 +/- 2.5) x 10(-12), and (8.8 +/- 1.8) x 10(-12 ) cm(3) molecule(-1) s(-1), respectively. Using a pulse radiolysis met hod we measured k(F+HFE-7100) = (1.6 +/- 0.6) x 10(-11) cm(3) molecule (-1) s(-1). Using a Fourier transform infrared spectroscopic technique rate, constants for the reaction of F and Cl atoms with HFE-7100 and Cl atoms with C4F9OC(O)H were determined to be (1.3 +/- 0.3) x 10(-11) , (9.7 +/- 1.4) x 10(-14), and (1.6 +/- 0.7) x 10(-14) cm(3) molecule( -1) s(-1), respectively. Finally, it was determined that the sole atmo spheric fate of C4F9OCH2O . radicals is reaction with O-2 to give C4F9 OC(O)H (perfluorobutyl formate). The results are discussed with respec t to the atmospheric chemistry of HFE-7100.