Atmospheric degradation of fluoroesters (FESs): Gas-phase reactivity study towards OH radicals at 298 K

Using the relative technique, rate coefficients have been measured for the gas phase reactions of hydroxyl radicals with four fluoroacetates, methyl trifluoroacetate (CF3COOCH3), ethyl trifluoroacetate (CF3COOCH2CH3), methyl difluoroacetate (CF2HCOOCH3) and 2,2,2-trifluoroethyl trifluoroacetate (CF3COOCH2CF3). Experiments were carried out at 296±2 K and atmospheric pressure (∼750 Torr) using nitrogen or synthetic air as bath gases. The following rate coefficients were derived for the reaction of OH radicals (in units of cm3 mol−1 s−1) with CF3COOCH3, k=(4.97±1.04)×10−14, CF3COOCH2CH3, k=(2.64±0.59)×10−13, CF2HCOOCH3, k=(1.48±0.34)×10−13 and CF3COOCH2CF3, (1.05±0.23)×10−13. The rate constants obtained are compared with previous literature data of other volatile organic compounds to establish reactivity trends. Atmospheric implications are discussed in terms of lifetimes and fates of the fluoroacetates in the troposphere.