A product study of the isoprene+NO<sub>3</sub> reaction
Oxidation of isoprene through reaction with NO<sub>3</sub> radicals is a significant sink for isoprene that persists after dark. The main products of the reaction are multifunctional nitrates. These nitrates constitute a significant NO<sub>x</sub> sink in the nocturnal bounda...
| Main Authors: | , , , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2009-07-01
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| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/9/4945/2009/acp-9-4945-2009.pdf |
| Summary: | Oxidation of isoprene through reaction with NO<sub>3</sub> radicals is a significant sink for isoprene that persists after dark. The main products of the reaction are multifunctional nitrates. These nitrates constitute a significant NO<sub>x</sub> sink in the nocturnal boundary layer and they likely play an important role in formation of secondary organic aerosol. Products of the isoprene+NO<sub>3</sub> reaction will, in many locations, be abundant enough to affect nighttime radical chemistry and to persist into daytime where they may represent a source of NO<sub>x</sub>. Product formation in the isoprene + NO<sub>3</sub> reaction was studied in a smog chamber at Purdue University. Isoprene nitrates and other hydrocarbon products were observed using Proton Transfer Reaction-Mass Spectrometry (PTR-MS) and reactive nitrogen products were observed using Thermal Dissociation–Laser Induced Fluorescence (TD-LIF). The organic nitrate yield is found to be 65±12% of which the majority was nitrooxy carbonyls and the combined yield of methacrolein and methyl vinyl ketone (MACR+MVK) is found to be ∼10%. PTR-MS measurements of nitrooxy carbonyls and TD-LIF measurements of total organic nitrates agreed well. The PTR-MS also observed a series of minor oxidation products which were tentatively identified and their yields quantified These other oxidation products are used as additional constraints on the reaction mechanism. |
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| ISSN: | 1680-7316 1680-7324 |