TROPOSPHERIC DEGRADATION PRODUCTS OF CH2FCF3 (HFC-134A)

Chlorine atom-initiated photooxidations of CH2FCF3 (HFC-134a) in O2-N2 diluent were carried out to identify the products formed from the CF3CHFO radical reactions and to determine the product yields as a function of temperature, pressure and O2 concentration. CF3C(O)F and HC(O)F were the major 'first-generation' products observed, along with smaller yields of C(O)F2 and, as yet, undetermined yields of CF3OOOCF3 and CF3OOC(O)E The relative importance of the two major CF3CHFO reaction pathways, CF3CHFO + O2 ---> k(O2) CF3C(O)F + HO2 CF3CHFO ---> k(d) HC(O)F + CF3 is expressed by the rate constant ratio k(O2)/k(d) = 3.2 x 10(-25) e(3510+/-470)/T cm3 molecule-1 The decomposition reaction leading to HC(O)F and CF3 radical products is predicted to be the dominant pathway at the Earth's surface while mainly CF3C(O)F formation will occur at the tropopause.