Quantum Chemical and Kinetic Study on Polychlorinated Naphthalene Formation from 3-Chlorophenol Precursor.
Quantum Chemical and Kinetic Study on Polychlorinated Naphthalene Formation from 3-Chlorophenol Precursor.
复制标题
3-氯苯酚前体形成多氯化萘的量子化学和动力学研究
DOI：
10.3390/ijms160920620
复制
发表时间：
2015-08-31
影响因子：
5.6
通讯作者：
Zhang Q
中科院分区：
文献类型：
--
作者：
Xu F;Shi X;Zhang Q
多氯化萘（PCNs）是最小的氯化多环芳烃（Cl-PAH），通常被称为二恶英类化合物。氯酚类化合物是多氯化萘形成的重要前体。本文采用密度泛函理论（DFT）和正则变分过渡态理论（CVT）结合小曲率隧穿贡献（SCT）对3-CP前驱体气相生成多氯化萘（PCNs）的机理和动力学进行了理论研究。讨论了不同PCN生成途径的反应优先级。在600 - 1200 K的宽温度范围内推导出关键基本步骤的速率常数。与实验观察和我们以前的工作进行了比较，从2-CP和4-CP的PCN形成的机制。该研究表明，以Cl消除结束的途径比以3-CP前体的H消除结束的途径更有利。MCN的形成势大于DCN。一氯酚的氯取代模式对多氯化萘产物的异构体模式和生成潜力有重要影响。研究结果可作为详细参数输入到环境多氯化萘控制和预测模型中，用于确定多氯化萘的生成途径，减少多氯化萘的排放，制定多氯化萘的控制策略。
Polychlorinated naphthalenes (PCNs) are the smallest chlorinated polycyclic aromatic hydrocarbons (Cl-PAHs) and are often called dioxin-like compounds. Chlorophenols (CPs) are important precursors of PCN formation. In this paper, mechanistic and kinetic studies on the homogeneous gas-phase formation mechanism of PCNs from 3-CP precursor were investigated theoretically by using the density functional theory (DFT) method and canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT). The reaction priority of different PCN formation pathways were disscussed. The rate constants of crucial elementary steps were deduced over a wide temperature range of 600−1200 K. The mechanisms were compared with the experimental observation and our previous works on the PCN formation from 2-CP and 4-CP. This study shows that pathways ended with Cl elimination are favored over those ended with H elimination from the 3-CP precursor. The formation potential of MCN is larger than that of DCN. The chlorine substitution pattern of monochlorophenols has a significant effect on isomer patterns and formation potential of PCN products. The results can be input into the environmental PCN controlling and prediction models as detailed parameters, which can be used to confirm the formation routes of PCNs, reduce PCN emission and establish PCN controlling strategies.