Kinetics Studies of the Photochemistry of Isoprene-derived 4,1-nitrooxyaldehyde

Abstract:

In the boundary layer environments influenced by BVOC emissions, carbonyl nitrates are produced from NO₃-initiated isoprene oxidation, which constitutes a potentially important NO_x reservoir. The formation and degradation processes of organic nitrates affect the dynamics of reactive nitrogen and ground-level ozone. To better understand the fate of these organic nitrates, the isomer 4-nitrooxy-2-methyl-2-buten-1-al (4,1-nitrooxyaldehyde) was synthesized for photochemical reaction chamber experiments. The rate constants for reaction of this species with O₃ and OH, as well as its photolysis rate were determined. A chemical ionization mass spectrometer (CIMS) with I(H₂O)_n^- as the reagent ion was used to monitor the loss of isoprene nitrooxyaldehyde and formation of its oxidation products. Possible reaction pathways are discussed based on the CIMS measurements.