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| Titel |
Aqueous-phase ozonolysis of methacrolein and methyl vinyl ketone: a potentially important source of atmospheric aqueous oxidants |
| VerfasserIn |
Z. M. Chen, H. L. Wang, L. H. Zhu, C. X. Wang, C. Y. Jie, W. Hua |
| 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 ; 8, no. 8 ; Nr. 8, no. 8 (2008-04-24), S.2255-2265 |
| Datensatznummer |
250006064
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| Publikation (Nr.) |
 copernicus.org/acp-8-2255-2008.pdf |
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| Zusammenfassung |
| Recent studies indicate that isoprene and its gas-phase oxidation products could contribute a
considerable amount of aerosol through aqueous-phase acid-catalyzed
oxidation with hydrogen peroxide (H2O2), although the
source of H2O2 is unclear. The present study revealed a
potentially important route to the formation of aqueous oxidants,
including H2O2, from the aqueous-phase ozonolysis of
methacrolein (MAC) and methyl vinyl ketone (MVK). Laboratory
simulation was used to perform the atmospheric aqueous-phase
ozonolysis at different pHs and temperatures. Unexpectedly high
molar yields of the products, including hydroxylmethyl hydroperoxide
(HMHP), formaldehyde (HCHO) and methylglyoxal (MG), of both of these
reaction systems have been seen. Moreover, these yields are almost
independent of pH and temperature and are as follows: (i) for
MAC–O3, 70.3±6.3% HMHP, 32.3±5.8% HCHO and
98.6±5.4% MG; and (ii) for MVK–O3, 68.9±9.7% HMHP,
13.3±5.8% HCHO and 75.4±7.9% MG. A yield of 24.2±3.6% pyruvic acid has been detected for MVK–O3. HMHP is
unstable in the aqueous phase and can transform into H2O2
and HCHO with a yield of 100%. We suggest that the aqueous-phase
ozonolysis of MAC and MVK can contribute a considerable amount of
oxidants in a direct and indirect mode to the aqueous phase and that
these compounds might be the main source of aqueous-phase oxidants.
The formation of oxidants in the aqueous-phase ozonolysis of MAC and MVK can lead to substantial aerosol formation from the
aqueous-phase acid-catalyzed reaction of H2O2 with MAC,
even if there are no other sources of oxidants. |
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