Atmospheric Chemistry of Hydrofluoroethers: Reaction of a Series of Hydrofluoroethers with OH Radicals and Cl Atoms, Atmospheric Lifetimes, and Global Warming Potentials

Abstract

The kinetics of the OH radical and Cl atom reactions with nine fluorinated ethers have been studied by the relative rate method at 298 K and 1013 hPa using gas chromatography-mass spectroscopy (GC-MS) detection: k(OH + CH3CH2OCF3) ) (1.55 ( 0.25)×10-13, k(OH + CF3CH2OCH3) ) (5.7 ( 0.8)×10-13, k(OH + CF3CH2OCHF2) ) (9.1 ( 1.1) × 10-15, k(OH + CF3CHFOCHF2) ) (6.5 ( 0.8) × 10-15, k(OH + CHF2CHFOCF3) ) (6.8 ( 1.1)×10-15, k(OH + CF3CHFOCF3) < 1×10-15, k(OH + CF3CHFCF2OCHF2) ) (1.69 ( 0.26) × 10-14, k(OH + CF3CHFCF2OCH2CH3) ) (1.47 ( 0.13) × 10-13, k(OH + CF3CF2CF2OCHFCF3) < 1×10-15, k(Cl + CH3CH2OCF3) ) (2.2 ( 0.8)×10-12, k(Cl + CF3CH2OCH3) ) (1.8 ( 0.9) × 10-11, k(Cl + CF3CH2OCHF2) ) (1.5 ( 0.4) × 10-14, k(Cl + CF3CHFOCHF2) ) (1.1 ( 1.9) × 10-15, k(Cl + CHF2CHFOCF3) ) (1.2 ( 2.0) × 10-15, k(Cl + CF3CHFOCF3) < 3 × 10-15, k(Cl + CF3CHFCF2OCHF2) < 6 × 10-16, k(Cl + CF3CHFCF2OCH2CH3) ) (3.1 ( 1.1) × 10-12, and k(Cl + CF3CF2CF2OCHFCF3) < 3×10-15 cm3 molecule-1 s-1. The error limits include three standard deviations (3σ) from the statistical data analyses, as well as the errors in the rate coefficients of the reference compounds that are used. Infrared absorption cross sections and estimates of the trophospheric lifetimes and the global warming potentials of the fluorinated ethers are presented. The atmospheric degradation of the compounds is discussed.