Atmospheric chemistry of t-CF3CH=CHCl: products and mechanisms of the gas-phase reactions with chlorine atoms and hydroxyl radicals

Mads Peter Sulbæk Andersen, Ole John Nielsen, M. D. Hurley, T. J. Wallington

17 Citations (Scopus)

Abstract

FTIR-smog chamber techniques were used to study the products and mechanisms of the Cl atom and OH radical initiated oxidation of trans-3,3,3-trifluoro-1- chloro-propene, t-CF 3CHCHCl, in 700 Torr of air or N 2/O 2 diluent at 296 ± 2 K. The reactions of Cl atoms and OH radicals with t-CF 3CHCHCl occur via addition to the CC double bond; chlorine atoms add 15 ± 5% at the terminal carbon and 85 ± 5% at the central carbon, OH radicals add approximately 40% at the terminal carbon and 60% at the central carbon. The major products in the Cl atom initiated oxidation of t-CF 3CHCHCl were CF 3CHClCHO and CF 3C(O)CHCl 2, minor products were CF 3CHO, HCOCl and CF 3COCl. The yields of CF 3C(O)CHCl 2, CF 3CHClCOCl and CF 3COCl increased at the expense of CF 3CHO, HCOCl and CF 3CHClCHO as the O 2 partial pressure was increased over the range 10-700 Torr. Chemical activation plays a significant role in the fate of CF 3CH(O)CHCl 2 and CF 3CClHCHClO radicals. In addition to reaction with O 2 to yield CF 3COCl and HO 2 the major competing fate of CF 3CHClO is Cl elimination to give CF 3CHO (not C-C bond scission as previously thought). As part of this study k(Cl + CF 3C(O)CHCl 2) = (2.3 ± 0.3) × 10 -14 and k(Cl + CF 3CHClCHO) = (7.5 ± 2.0) × 10 -12 cm 3 molecule -1 s -1 were determined using relative rate techniques. Reaction with OH radicals is the major atmospheric sink for t-CF 3CHCHCl. Chlorine atom elimination giving the enol CF 3CHCHOH appears to be the sole atmospheric fate of the CF 3CHCHClOH radicals. The yield of CF 3COOH in the atmospheric oxidation of t-CF 3CHCHCl will be negligible (<2%). The results are discussed with respect to the atmospheric chemistry and environmental impact of t-CF 3CHCHCl.

Original languageEnglish
JournalPhysical Chemistry Chemical Physics
Volume14
Issue number5
Pages (from-to)1735-1748
Number of pages14
ISSN1463-9076
DOIs
Publication statusPublished - 7 Feb 2012

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