Issue 90, 2015

Kinetic study of the OH and Cl-initiated oxidation, lifetimes and atmospheric acceptability indices of three halogenated ethenes

Abstract

The gas-phase kinetics for the reactions of OH radicals and Cl atoms with (E/Z)-CHCl[double bond, length as m-dash]CHF, (E/Z)-CFCl[double bond, length as m-dash]CFCl, and CCl2[double bond, length as m-dash]CF2 were investigated at room-temperature and atmospheric pressure. A conventional relative-rate technique was used to determine the rate coefficients k(OH + (E/Z)-CHCl[double bond, length as m-dash]CHF) = (6.3 ± 1.2) × 10−12, k(OH + (E/Z)-CFCl[double bond, length as m-dash]CFCl) = (1.6 ± 0.2) × 10−12, k(OH + CCl2[double bond, length as m-dash]CF2) = (5.0 ± 0.7) × 10−12, k(Cl + (E/Z)-CHCl[double bond, length as m-dash]CHF) = (11 ± 2) × 10−11, k(Cl + (E/Z)-CFCl[double bond, length as m-dash]CFCl) = (5.4 ± 1.3) × 10−11, and k(Cl + CCl2[double bond, length as m-dash]CF2) = (6.3 ± 1.5) × 10−11 cm3 per molecule per s. These rate coefficients were compared with previous literature data to analyze the effect of halogen substitution in ethenes on the reactivity towards OH and Cl, and used to estimate the global atmospheric lifetimes for the studied haloethenes. The calculated lifetimes, using average global concentrations of OH radicals and Cl atoms, indicate that the atmospheric loss of these compounds is determined by the OH-initiated oxidation. Also, the atmospheric implications of the halogenated ethenes studied were evaluated by estimating acceptability indices such as the global warming potential (GWP) and the ozone depletion potential (ODP). From these potentials, the contribution of (E/Z)-CHCl[double bond, length as m-dash]CHF, (E/Z)-CFCl[double bond, length as m-dash]CFCl, and CCl2[double bond, length as m-dash]CF2 to radiative forcing of climate change and to ozone layer depletion is expected to be negligible.

Graphical abstract: Kinetic study of the OH and Cl-initiated oxidation, lifetimes and atmospheric acceptability indices of three halogenated ethenes

Article information

Article type
Paper
Submitted
11 Jul 2015
Accepted
24 Aug 2015
First published
24 Aug 2015

RSC Adv., 2015,5, 73501-73509

Kinetic study of the OH and Cl-initiated oxidation, lifetimes and atmospheric acceptability indices of three halogenated ethenes

J. A. Barrera, P. R. Dalmasso, J. P. Aranguren Abrate, R. A. Taccone and S. I. Lane, RSC Adv., 2015, 5, 73501 DOI: 10.1039/C5RA13589C

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