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| Titel |
Reactions of isoprene and sulphoxy radical-anions – a possible source of atmospheric organosulphites and organosulphates |
| VerfasserIn |
K. J. Rudziński, L. Gmachowski, I. Kuznietsova |
| 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 ; 9, no. 6 ; Nr. 9, no. 6 (2009-03-24), S.2129-2140 |
| Datensatznummer |
250007099
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| Publikation (Nr.) |
 copernicus.org/acp-9-2129-2009.pdf |
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| Zusammenfassung |
| Transformation of isoprene coupled with auto-oxidation of SIV in
aqueous solutions was studied experimentally and by chemical-kinetic
modelling over a broad range of solution acidities (pH=3–9) to complement
the research on aqueous-phase and heterogeneous transformation of isoprene
reported recently by many laboratories. Isoprene significantly slowed down
the auto-oxidation in acidic and basic solutions, and accelerated it slightly
in neutral solutions. Simultaneously, production of sulphate ions and
formation of solution acidity were significantly reduced. Formation of
sulphite and sulphate derivatives of isoprene - sulphurous acid
mono-(2-methyl-4-oxo-but-2-enyl) ester (m/z=163), sulphurous acid
mono-(4-hydroxy-2-methyl-but-2-enyl) ester (m/z=165), sulphuric
acid mono-(2-methyl-4-oxo-but-2-enyl) ester (m/z=179), sulphuric
acid mono-(4-hydroxy-2-methyl-but-2-enyl) ester (m/z=181), and
possible structural isomers of these species – was indicated by electrospray
ionisation mass spectrometric analysis of post-reaction mixtures. The
experimental results were explained by changes in a subtle quantitative
balance of three superimposed processes whose rates depended in different
manner on the acidity of reacting solutions – the scavenging of sulphoxy
radical-anions by isoprene, the formation of sulphoxy radical-anions during
further reactions of isoprene radicals, and the auto-oxidation of
SIV itself. A chemical mechanism based on this idea was explored
numerically to show good agreement with experimental data. In basic and
neutral solutions, the model overestimated the consumption of isoprene,
probably because reactions of primary sulphite and sulphate derivatives of
isoprene with sulphoxy radical-anions were not included. Interaction of
isoprene with sulphur(IV) species and oxygen can possibly result in formation
of new organosulphate and organosulphite components of atmospheric aerosols
and waters, and influence the distribution of reactive sulphur and oxygen
species in isoprene-emitting organisms exposed to SIV pollutants. |
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