Air Pollution Research Center, University of California Riverside, Riverside, California 92521, USA.
Environ Sci Technol. 2012 Aug 7;46(15):8198-204. doi: 10.1021/es301865t. Epub 2012 Jul 18.
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.
萘通常是大气中最丰富的多环芳烃，通过加成与 OH 自由基反应形成 OH-萘加合物。这些 OH-萘加合物与 O(2)和 NO(2)反应，在 NO(2)混合比约为 60 ppbv 的空气中，这两个反应同样重要。2-甲酰肉桂醛 [o-HC(O)C(6)H(4)CH═CHCHO]是萘与 OH 自由基反应的主要产物，其由 OH-萘加合物与 NO(2)反应生成的产率约为 56%。我们已经在平均 NO(2)浓度为 1.2×10(11)、1.44×10(12)和 1.44×10(13)分子 cm(-3)（混合比分别为 0.005、0.06 和 0.6 ppmv）的空气中，以相对基准测量了萘与 OH 自由基反应生成 2-甲酰肉桂醛的生成产率。这些 NO(2)浓度覆盖了 OH-萘加合物与 O(2)反应约 90%的时间和与 NO(2)反应约 90%的时间对应的条件范围。2-甲酰肉桂醛的生成产率随 NO(2)浓度的降低而降低，并且根据 OH-萘加合物+O(2)反应的 14%产率，OH-萘加合物+NO(2)反应的产率为 56%。基于之前对萘与 OH 反应生成的乙二醛和邻苯二甲醛的测量以及文献中对单环芳烃与 OH 自由基反应的测量数据，OH-萘加合物与 O(2)的反应与 OH-单环加合物+O(2)反应明显不同。
