 |
| Titel |
The relative importance of competing pathways for the formation of high-molecular-weight peroxides in the ozonolysis of organic aerosol particles |
| VerfasserIn |
M. Mochida, Y. Katrib, J. T. Jayne, D. R. Worsnop, S. T. Martin |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 6, no. 12 ; Nr. 6, no. 12 (2006-10-27), S.4851-4866 |
| Datensatznummer |
250004158
|
| Publikation (Nr.) |
 copernicus.org/acp-6-4851-2006.pdf |
|
|
|
|
|
| Zusammenfassung |
| High-molecular-weight (HMW) organic compounds are an important component of
atmospheric particles, although their origins, possibly including in situ
formation pathways, remain incompletely understood. This study investigates
the formation of HMW organic peroxides through reactions involving
stabilized Criegee intermediates (SCI's). The model system is methyl oleate
(MO) mixed with dioctyl adipate (DOA) and myristic acid (MA) in submicron
aerosol particles, and Criegee intermediates are formed by the ozonolysis of the
double bond in methyl oleate. An aerosol flow tube coupled to a
quadrupole aerosol mass spectrometer (AMS) is employed to determine the
relative importance of different HMW organic peroxides following the ozonolysis of different
mixing mole fractions of MO in DOA and MA. Possible peroxide products include secondary
ozonides (SOZ's), α-acyloxyalkyl hydroperoxides and α-acyloxyalkyl alkyl peroxides (αAAHP-type compounds), diperoxides,
and monoperoxide oligomers. Of these, the AMS data identify two SOZ's as major
HMW products in the ozonolysis of pure methyl oleate as well as in an inert matrix of DOA to
as low as 0.04 mole fraction MO. In comparison, in mixed particles of MO and
MA, αAAHP-type compounds form in high yields for MO mole
fractions of 0.5 or less, suggesting that SCI's efficiently attack the carboxylic
acid group of myristic acid. The reactions of SCI's with carboxylic acid
groups to form αAAHP-type compounds therefore compete with those of
SCI's with aldehydes to form SOZ's, provided that both types of
functionalities are present at significant concentrations. The results
therefore suggest that SCI's in atmospheric particles contribute to the
transformation of carboxylic acids and other protic groups into HMW organic peroxides. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|