Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene
Peroxy radical reactions (RO<sub>2</sub> + RO<sub>2</sub>) from the NO<sub>3</sub>-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products t...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2012-08-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/12/7499/2012/acp-12-7499-2012.pdf |
| _version_ | 1818179870496129024 |
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| author | J. H. Seinfeld P. O. Wennberg H. G. Kjaergaard N. L. Ng A. W. H. Chan A. J. Kwan |
| author_facet | J. H. Seinfeld P. O. Wennberg H. G. Kjaergaard N. L. Ng A. W. H. Chan A. J. Kwan |
| author_sort | J. H. Seinfeld |
| collection | DOAJ |
| description | Peroxy radical reactions (RO<sub>2</sub> + RO<sub>2</sub>) from the NO<sub>3</sub>-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (~ 80%), consistent with other studies. We further see evidence of significant hydroxyl radical (OH) formation in this system, which we propose comes from RO<sub>2</sub> + HO<sub>2</sub> reactions with a yield of ~38–58%. An additional OH source is the second generation oxidation of the nitrooxyhydroperoxide, which produces OH and a dinitrooxyepoxide with a yield of ~35%. The branching ratio of the radical propagating, carbonyl- and alcohol-forming, and organic peroxide-forming channels of the RO<sub>2</sub> + RO<sub>2</sub> reaction are found to be ~18–38%, ~59–77%, and ~3–4%, respectively. HO<sub>2</sub> formation in this system is lower than has been previously assumed. Addition of RO<sub>2</sub> to isoprene is suggested as a possible route to the formation of several isoprene C<sub>10</sub>-organic peroxide compounds (ROOR). The nitrooxy, allylic, and C<sub>5</sub> peroxy radicals present in this system exhibit different behavior than the limited suite of peroxy radicals that have been studied to date. |
| first_indexed | 2024-12-11T21:10:45Z |
| format | Article |
| id | doaj.art-29001dd1840f4ddb81094d4bb14bb46d |
| institution | Directory Open Access Journal |
| issn | 1680-7316 1680-7324 |
| language | English |
| last_indexed | 2024-12-11T21:10:45Z |
| publishDate | 2012-08-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Chemistry and Physics |
| spelling | doaj.art-29001dd1840f4ddb81094d4bb14bb46d2022-12-22T00:50:44ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242012-08-0112167499751510.5194/acp-12-7499-2012Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isopreneJ. H. SeinfeldP. O. WennbergH. G. KjaergaardN. L. NgA. W. H. ChanA. J. KwanPeroxy radical reactions (RO<sub>2</sub> + RO<sub>2</sub>) from the NO<sub>3</sub>-initiated oxidation of isoprene are studied with both gas chromatography and a chemical ionization mass spectrometry technique that allows for more specific speciation of products than in previous studies of this system. We find high nitrate yields (~ 80%), consistent with other studies. We further see evidence of significant hydroxyl radical (OH) formation in this system, which we propose comes from RO<sub>2</sub> + HO<sub>2</sub> reactions with a yield of ~38–58%. An additional OH source is the second generation oxidation of the nitrooxyhydroperoxide, which produces OH and a dinitrooxyepoxide with a yield of ~35%. The branching ratio of the radical propagating, carbonyl- and alcohol-forming, and organic peroxide-forming channels of the RO<sub>2</sub> + RO<sub>2</sub> reaction are found to be ~18–38%, ~59–77%, and ~3–4%, respectively. HO<sub>2</sub> formation in this system is lower than has been previously assumed. Addition of RO<sub>2</sub> to isoprene is suggested as a possible route to the formation of several isoprene C<sub>10</sub>-organic peroxide compounds (ROOR). The nitrooxy, allylic, and C<sub>5</sub> peroxy radicals present in this system exhibit different behavior than the limited suite of peroxy radicals that have been studied to date.http://www.atmos-chem-phys.net/12/7499/2012/acp-12-7499-2012.pdf |
| spellingShingle | J. H. Seinfeld P. O. Wennberg H. G. Kjaergaard N. L. Ng A. W. H. Chan A. J. Kwan Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene Atmospheric Chemistry and Physics |
| title | Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene |
| title_full | Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene |
| title_fullStr | Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene |
| title_full_unstemmed | Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene |
| title_short | Peroxy radical chemistry and OH radical production during the NO<sub>3</sub>-initiated oxidation of isoprene |
| title_sort | peroxy radical chemistry and oh radical production during the no sub 3 sub initiated oxidation of isoprene |
| url | http://www.atmos-chem-phys.net/12/7499/2012/acp-12-7499-2012.pdf |
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