A product study of the isoprene+NO3 reaction
Other literature type
Perring, A. E.
Wooldridge, P. J.
Lockwood, A. L.
Mielke, L. H.
Shepson, P. B.
Cohen, R. C.
(issn: 1680-7324, eissn: 1680-7324)
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.