Atmospheric chemistry of CF3CH‗CH2 and C4F9CH‗CH2: products of the gas-phase reactions with Cl atoms and OH radicals
Research output: Contribution to journal › Journal article › Research › peer-review
FTIR-smog chamber techniques were used to study the products of the Cl atom and OH radical initiated oxidation of CF3CHCH2 in 700 Torr of N-2/O-2, diluent at 296 K. The Cl atom initiated oxidation of CF3CHCH2 in 700 Torr of air in the absence of NOx gives CF3C(O)CH2Cl and CF3CHO in yields of 70 +/- 5% and 6.2 +/- 0.5 respectively. Reaction with Cl atoms proceeds via addition to the > CC <double bond (74 +/- 4% to the terminal and 26 +/- 4% to the central carbon atom) and leads to the formation of CF3CH(O)CH2Cl and CF3CHClCH2O radicals. Reaction with O-2 and decomposition via C-C bond scission are competing loss mechanisms for CF3CH(O)CH2Cl radicals, k(O2)/k(diss) = (3.8 +/- 1.8) x 10(-18) cm(3) molecule(-1). The atmospheric fate of CF3CHClCH2O radicals is reaction with O-2 to give CF3CHClCHO. The OH radical initiated oxidation of CxF2x+1CHCH2 (x = 1 and 4) in 700 Torr of air in the presence of NOx gives CxF2x+1CHO in a yield of 88 +/- 9 Reaction with OH radicals proceeds via addition to the > CC <double bond leading to the formation of CxF2x+1C(O)HCH2OH and CxF2x+1CHOHCH2O radicals. Decomposition via C-C bond scission is the sole fate of CxF2x+1CH(O)CH2OH and CxF2x+1CH(OH)CH2O radicals. As part of this work a rate constant of k(Cl+CF3C(O)CH2Cl) = (5.63 +/- 0.66) x 10(-14) cm(3) molecule(-1) s(-1) was determined. The results are discussed with respect to previous literature data and the possibility that the atmospheric oxidation of CxF2x+1CHCH2 contributes to the observed burden of perfluorocarboxylic acids, CxF2x+1COOH, in remote locations.
|Journal||Journal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory|
|Number of pages||7|
|Publication status||Published - 2007|