Rate constants and Arrhenius parameters for the reactions of OH radicals and Cl atoms with CF3CH2OCHF2, CF3CHClOCHF2 and CF3CH2OCClF2, using the discharge-flow/resonance fluorescence method

Rate constants have been determined for the reactions of OH radicals and Cl atoms with the three partially halogenated methyl-ethyl ethers, CF\(_3\)CH\(_2\)OCHF\(_2\), CF\(_3\)CHClOCHF\(_2\) and CF\(_3\)CH\(_2\)OCClF\(_2\), using discharge-flow techniques to generate the OH radicals and the Cl atoms and resonance fluorescence to observe changes in their relative concentrations in the presence of added ether. For each combination of radical and ether, experiments were carried out at three temperatures between 292 and 410 K, yielding the following Arrhenius expressions for the rate constants within this range of temperature:

OH + CF\(_3\)CH\(_2\)OCHF\(_2\): \(k\) = (2.0\(\pm\)0.8) \(\times\) 10\(^{-11}\) exp( – 2110 \(\pm\) 150 K / T) cm\(^3\) molecule\(^{-1}\) s\(^{-1}\)
OH + CF\(_3\)CHClOCHF\(_2\): \(k\) = (4.5 \(\pm\) 1.3) \(\times\) 10\(^{-13}\) exp( – 940 \(\pm\) 100 K / T) cm\(^3\) molecule\(^{-1}\) s\(^{-1}\)
OH + CF\(_3\)CH\(_2\)OCClF\(_2\): \(k\) = (1.6 \(\pm\) 0.6) \(\times\) 10\(^{-12}\) exp( – 1100 \(\pm\) 125 K / T) cm\(^3\) molecule\(^{-1}\) s\(^{-1}\)
Cl + CF\(_3\)CH\(_2\)OCHF\(_2\): \(k\) = (6.1 \(\pm\) 1.4) \(\times\) 10\(^{-12}\) exp( – 1830 \(\pm\) 90 K / T) cm\(^3\) molecule\(^{-1}\) s\(^{-1}\)
Cl + CF\(_3\)CHClOCHF\(_2\): \(k\) = (7.8 \(\pm\) 2.6) \(\times\) 10\(^{-11}\) exp( – 2980 \(\pm\) 130 K / T) cm\(^3\) molecule\(^{-1}\) s\(^{-1}\)
Cl + CF\(_3\)CH\(_2\)OCClF\(_2\): \(k\) = (2.2 \(\pm\) 0.2) \(\times\) 10\(^{-11}\) exp( – 2700 \(\pm\) 40 K / T) cm\(^3\) molecule\(^{-1}\) s\(^{-1}\)

The results are compared with those obtained previously for the same and related reactions of OH radicals and Cl atoms, and the atmospheric implications of the results are considered briefly.