Atmospheric chemistry of C2F5CHO: mechanism of the C2F5C(O)O2+ HO2 reaction

Smog chamber/FTIR techniques were used to study the gas-phase reaction of C2F5C(O)O2 with HO2 radicals in 100–700 Torr of air, or O2, diluent at 296 K. The reaction proceeds by two pathways leading to formation of C2F5C(O)OH and O3 in a yield of 24 ± 4% and C2F5C(O)O radicals, OH radicals and O2 in a yield of 76 ± 4%. The gas phase reaction of CnF2n + 1C(O)O2 with HO2 radicals offers a potential explanation for at least part of the observed environmental burden of fluorinated carboxylic acids, CnF2n + 1C(O)OH. As part of this work an upper limit for the rate constant of reaction of Cl atoms with C2F5C(O)OH at 296 K was determined; k(Cl + C2F5C(O)OH)