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| Titel |
Kinetic measurements of the reactivity of hydrogen peroxide and ozone towards small atmospherically relevant aldehydes, ketones and organic acids in aqueous solutions |
| VerfasserIn |
L. Schöne, H. Herrmann |
| 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 ; 14, no. 9 ; Nr. 14, no. 9 (2014-05-07), S.4503-4514 |
| Datensatznummer |
250118685
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| Publikation (Nr.) |
 copernicus.org/acp-14-4503-2014.pdf |
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| Zusammenfassung |
| Free radical reactions are
an important degradation process for organic compounds within the aqueous
atmospheric environment. Nevertheless, non-radical oxidants such as hydrogen
peroxide and ozone also contribute to the degradation and conversion of these
substances (Tilgner and Herrmann, 2010). In this work, kinetic investigations
of non-radical reactions were conducted using UV / Vis spectroscopy
(dual-beam spectrophotometer and stopped flow technique) and a capillary
electrophoresis system applying pseudo-first order kinetics to reactions of
glyoxal, methylglyoxal, glycolaldehyde, glyoxylic, pyruvic and glycolic acid
as well as methacrolein (MACR) and methyl vinyl ketone (MVK) with
H2O2 and ozone at 298 K. The measurements indicate rather small
rate constants at room temperature of k2nd <
3 M−1 s−1 (except for the unsaturated
compounds exposed to ozone). Compared to radical reaction rate constants the
values are about 10 orders of magnitude smaller (kOH•
~109 M−1 s−1). However, when considering the much
larger non-radical oxidant concentrations compared to radical concentrations
in urban cloud droplets, calculated first-order conversion rate constants
change the picture towards H2O2 reactions becoming more important,
especially when compared to the nitrate radical. For some reactions
mechanistic suggestions are also given. |
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