Kinetics Studies of Isoprene-Derived 4,1-Nitrooxyaldehyde

Abstract:

Carbonyl nitrates are products of NO₃-initiated isoprene oxidation and are an important nighttime NO_x reservoir, in forest impacted atmospheric boundary layer environments. To better understand the fate of these organic nitrates, the isomer 4-nitrooxy-2-methyl-2-buten-1-al (4,1-nitrooxyaldehyde) was synthesized and purified for photochemical reaction chamber experiments. The rate constants for this molecule to react with O₃, NO₃, OH, as well as its photolysis rate were determined using the relative rate method. 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 will be discussed based on the CIMS measurements.