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| Titel |
A theoretical model on the formation mechanism and kinetics of highly toxic air pollutants from halogenated formaldehydes reacted with halogen atoms |
| VerfasserIn |
Y. M. Ji, H. H. Wang, Y. P. Gao, G. Y. Li, T. C. An |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 22 ; Nr. 13, no. 22 (2013-11-21), S.11277-11286 |
| Datensatznummer |
250085825
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| Publikation (Nr.) |
 copernicus.org/acp-13-11277-2013.pdf |
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| Zusammenfassung |
| The atmospheric reactions of halogenated formaldehydes with halogen atoms
were investigated by high-accuracy molecular orbital calculation. Our studies
showed that compared to X-addition pathway, the H-abstraction pathway was
demonstrated to be more preferred to form halogenated formyl radicals and
hydrogen halides (HX). In specific areas with abundant halogen atoms, such as
the marine boundary layer (MBL), halogenated formyl radical was
reacted easily with halogen atoms and finally transformed into HX and CO2 in the
presence of water; otherwise, this radical was degraded to CO2, halogen
gas, and halogenated oxide in the presence of O2 and halogen atoms. By
using the canonical variational transition state theory, the kinetics
calculations were performed within a wide atmospheric temperature range of
200–368 K, and theoretical values agreed well with the available
experimental data. Under atmospheric conditions, rate constants decreased as
altitude increased, and especially the rate constants of halogen atoms
reacted with FCHO quickly reduced. The kinetic results showed that although
the reactions of halogenated formaldehydes with F atoms occurred more easily
than did those with Cl and Br atoms, the two latter reactions were
still important atmospheric degradation process, especially in the MBL. The
modified Arrhenius equations of rate constants within the atmospheric
temperature range were fitted, which helped to understand the established
atmospheric model and estimated the contribution of title reactions to
atmospheric chemistry pollution. |
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