2-Formylcinnamaldehyde formation yield from the OH radical-initiated reaction of naphthalene: effect of NO(2) concentration.
Naphthalene, typically the most abundant polycyclic aromatic hydrocarbon in the atmosphere, reacts with OH radicals by addition to form OH-naphthalene adducts. These OH-naphthalene adducts react with O(2) and NO(2), with the two reactions being of equal importance in air at an NO(2) mixing ratio of ∼60 ppbv. 2-Formylcinnamaldehyde [o-HC(O)C(6)H(4)CH═CHCHO] is a major product of the OH radical-initiated reaction of naphthalene, with a yield from the reaction of OH-naphthalene adducts with NO(2) of ∼56%. We have measured, on a relative basis, the formation yield of 2-formylcinnamaldehyde from the OH radical-initiated reaction of naphthalene in air at average NO(2) concentrations of 1.2 × 10(11), 1.44 × 10(12), and 1.44 × 10(13) molecules cm(-3) (mixing ratios of 0.005, 0.06, and 0.6 ppmv, respectively). These NO(2) concentrations cover the range of conditions corresponding to the OH-naphthalene adducts reacting ∼90% of the time with O(2) to ∼90% of the time with NO(2). The 2-formylcinnamaldehyde formation yield decreased with decreasing NO(2) concentration, and a yield from the OH-naphthalene adducts + O(2) reaction of 14% is obtained based on a 56% yield from the OH-naphthalene adducts + NO(2) reaction. Based on previous measurements of glyoxal and phthaldialdehyde from the naphthalene + OH reaction and literature data for the OH radical-initiated reactions of monocyclic aromatic hydrocarbons, the reactions of OH-naphthalene adducts with O(2) appear to differ significantly from the OH-monocyclic adduct + O(2) reactions.
Air Pollution Research Center, University of California Riverside, Riverside, California 92521, USA.
Noriko
N
Nishino
Janet
J
Arey
Roger
R
Atkinson
D008401:Gas Chromatography-Mass Spectrometry; D017665:Hydroxyl Radical / Q000737:chemistry*; D009281:Naphthalenes / Q000737:chemistry*; D009585:Nitrogen Dioxide / Q000032:analysis*; D009764:o-Phthalaldehyde / Q000031:analogs & derivatives* / Q000138:chemical synthesis
C540086:2-formylcinnamaldehyde; D009281:Naphthalenes; C031721:naphthalene; D017665:Hydroxyl Radical; D009764:o-Phthalaldehyde; D009585:Nitrogen Dioxide