Air Pollution Research Center, Environmental Toxicology Graduate Program, Department of Environmental Sciences, University of California, Riverside, California 92521, USA.
Environ Sci Technol. 2009 Nov 15;43(22):8554-60. doi: 10.1021/es902018v.
Naphthalene and alkylnaphthalenes are the most abundant polycyclic aromatic hydrocarbons present in ambient air and are transformed mainly by chemical reaction with hydroxyl (OH) radicals during daylight hours. To better understand the reaction mechanisms, we have quantified glyoxal from the OH radical-initiated reactions of naphthalene, 1-methylnaphthalene, 1,4-dimethylnaphthalene, acenaphthene, and acenaphthylene as a function of the NO(2) concentration and, for the naphthalene reaction, also in the absence of NO(2). Glyoxal was formed as a first-generation product from the naphthalene, 1-methylnaphthalene, 1,4-dimethylnaphthalene, and acenaphthene reactions, and its yields were independent of the NO(2) concentration over the ranges employed, being 5% in the presence of NO(2) and 3% in the absence of NO(2) from naphthalene; approximately 3% from 1-methylnaphthalene; approximately 2% from 1,4-dimethylnaphthalene; approximately 10-15% from acenaphthene; and <2% from acenaphthylene. Second-generation formation of glyoxal was evident in the 1-methylnaphthalene, 1,4-dimethylnaphthalene, and acenaphthene reactions. For the naphthalene reaction, our results suggest that the reactions of the OH-naphthalene adducts with NO(2) and O(2) both lead to glyoxal formation in similar yield. Simultaneous measurements of phthaldialdehyde from naphthalene, 2-acetylbenzaldehyde from 1-methylnaphthalene, and 1,2-diacetylbenzene from 1,4-dimethylnaphthalene suggest that these C(n-2)-dicarbonyls are coproducts to glyoxal.
萘和烷基萘是环境空气中最丰富的多环芳烃，主要通过与羟基（OH）自由基在白天的化学反应转化。为了更好地理解反应机制，我们已经量化了来自 OH 自由基引发的萘、1-甲基萘、1,4-二甲基萘、苊和苊烯反应的乙二醛，作为 NO 2 浓度的函数，并且对于萘反应，也在没有 NO 2 的情况下。乙二醛是从萘、1-甲基萘、1,4-二甲基萘和苊的反应中作为第一代产物形成的，其产率在实验范围内与 NO 2 浓度无关，在有 NO 2 的情况下为 5%，在没有 NO 2 的情况下为 3%，从萘中；大约 3%来自 1-甲基萘；大约 2%来自 1,4-二甲基萘；大约 10-15%来自苊；并且来自苊烯的<2%。乙二醛的第二代形成在 1-甲基萘、1,4-二甲基萘和苊的反应中是明显的。对于萘反应，我们的结果表明，OH-萘加合物与 NO 2 和 O 2 的反应都以相似的产率导致乙二醛的形成。萘、1-甲基萘的邻苯二甲醛和 1,4-二甲基萘的 1,2-二乙酰苯的同时测量表明，这些 C（n-2）-二羰基化合物是乙二醛的共产物。
