Atmospheric chemistry of CF3CH‗CH2 and C4F9CH‗CH2: products of the gas-phase reactions with Cl atoms and OH radicals

T. Nakayama, K. Takahashi, Y. Matsumi, A. Toft, Mads Peter Sulbæk Andersen, Ole John Nielsen, R. L. Waterland, R. C. Buck, M. D. Hurley, T. J. Wallington

31 Citationer (Scopus)

Abstract

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.
OriginalsprogEngelsk
TidsskriftJournal of Physical Chemistry Part A: Molecules, Spectroscopy, Kinetics, Environment and General Theory
Vol/bind111
Udgave nummer5
Sider (fra-til)909-915
Antal sider7
ISSN1089-5639
DOI
StatusUdgivet - 2007

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