Atmospheric Chemistry of CH₃OCF₂CHF₂

Fourier transform infrared spectroscopy has been used to follow the reaction of CH₃OCF₂CHF₂ with either Cl or OH radicals within a photoreactor. Rate constants of k(OH + CH₃OCF₂CHF₂) = (2.25 ± 0.60) × 10^-14 cm³ molecule^-1 s^-1 and k(Cl + CH₃OCF₂CHF₂) = (2.50 ± 0.39) × 10^-13 cm³ molecule^-1 s^-1 were determined at 296 ± 2 K. Theoretical and experimental investigation of the Cl + CH₃OCF₂CHF₂ reaction identified the formation of two main products, HC(O)OCF₂CHF₂ and COF₂. Chlorine (and OH) radicals react with CH₃OCF₂CHF₂ by H-abstraction from either the -CH₃ or -CHF₂ site. Abstraction from the -CH₃ site was determined to constitute at least 60%, as determined from the formation of the primary product, HC(O)OCF₂CHF₂, which can only form from this abstraction site. At longer reaction times, HC(O)OCF₂CHF₂ further reacts and the yield of COF₂ approaches two, the maximum possible with the number of F atoms in the reactant. The atmospheric lifetime of CH₃OCF₂CHF₂ with OH radicals was determined to be 1.4 years. The global warming potentials over 20-, 100-, and 500-year time horizons were estimated to be 325, 88, and 25, respectively.