Atmospheric oxidation of phenanthrene initiated by OH radicals in the presence of O-2 and NOx - A theoretical study
Atmospheric oxidation of phenanthrene initiated by OH radicals in the presence of O-2 and NOx - A theoretical study
复制标题
O-2 和 NOx 存在下 OH 自由基引发菲的大气氧化 - 理论研究
DOI：
10.1016/j.scitotenv.2016.01.089
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发表时间：
2016
影响因子：
9.8
通讯作者：
Wang Wenxing
中科院分区：
文献类型：
--
作者：
Zhao Nan;Zhang Qingzhu;Wang Wenxing
菲（Phe）是城市大气中含量最丰富的多环芳烃（PAHs）之一。Phe的大气损失过程中最重要的是与OH自由基的反应。本文研究了在O2和NOx存在下，OH自由基引发的苯丙氨酸大气降解。通过密度泛函理论（DFT）计算阐明了可能的反应机理。计算结果表明，主要产物是一系列含氧的多环芳烃，包括菲咯、菲酮、菲醌和二醛。用Rice-Ramsperger-Kassel-Marcus（RRKM）理论计算了Phe与OH反应的初始阶段的速率常数。根据298 K和1 atm下计算的总速率常数为3.02 × 10− 11 cm 3 molecule − 1 s − 1，苯丙氨酸在大气中与OH气相反应的寿命估计为4.6 h。结合已有的实验数据，对菲大气氧化过程中含氧多环芳烃的形成机理进行了全面的研究，并有助于阐明其潜在的健康风险。
Phenanthrene (Phe) is one of the most abundant polycyclic aromatic hydrocarbons (PAHs) observed in polluted urban atmosphere. The most important atmospheric loss process of Phe is the reaction with OH radicals. The present work investigated OH radical-initiated atmospheric degradation of Phe in the presence of O2and NOx. The possible reaction mechanism was elucidated by density functional theory (DFT) calculations. Calculations show that the main products are a series of ring-retaining and ring-opening oxygenated PAHs containing phenanthrol, phenanthones, phenanthrenequinone, and dialdehydes. Rice–Ramsperger–Kassel–Marcus (RRKM) theory was employed to evaluate the rate constants for the initial steps of Phe with OH. The atmospheric lifetime of Phe relative to gas-phase reactions with OH is estimated to be 4.6 h, based on the calculated overall rate constant of 3.02 × 10− 11cm3molecule− 1s− 1at 298 K and 1 atm. Combined with available experimental data, this work also provides a comprehensive investigation of the formation mechanism of oxygenated PAHs in the atmospheric oxidation process of phenanthrene and should help to clarify its potential health risk.