Atmospheric oxidation of fluorinated ethers, E143a (CF3OCH3), E134 (CHF2OCHF2), and E125 (CHF2OCF3)

The atmospheric oxidation mechanisms of E143a (CF,OCH,), E134 (CHF2OCHF2), and E125 (CHF2OCF3) have been investigated using experimental and ab initio methodology. The oxidation of E143a produces the stable reservoir species trifluoromethyl formate, CF3OCOH, which further oxidizes to CF2O and CO2. O xidation of E134 and E125 shows the presence of only CF2O under the conditi on of high O-2 concentrations. Carbonyl fluoride can be formed from two com peting pathways involving the halogenated alkyl radicals formed from hydrog en abstraction of E134 and E125. CO bond fission reactions and O-2 addition reactions compete to produce carbonyl fluoride and a CFxH3-x radical fragm ent. Computational modeling of the reaction pathways provides insight into the molecular steps of the degradation process.