Theoretical Mechanistic and Kinetic Studies on Homogeneous Gas-Phase Formation of Polychlorinated Naphthalene from 2-Chlorophenol as Forerunner.
Theoretical Mechanistic and Kinetic Studies on Homogeneous Gas-Phase Formation of Polychlorinated Naphthalene from 2-Chlorophenol as Forerunner.
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以2-氯苯酚为先驱剂均相气相生成多氯化萘的理论机理和动力学研究
DOI：
10.3390/ijms161025641
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发表时间：
2015-10-26
影响因子：
5.6
通讯作者：
Wang W
中科院分区：
文献类型：
--
作者：
Xu F;Zhang R;Li Y;Zhang Q;Wang W
多氯联苯(PCN)是二恶英类化合物，在热和燃烧过程中与多氯二苯并对二恶英(PCDDs)和多氯二苯并呋喃(PCDf)一起形成。氯代酚(CP)是多氯联苯最重要的前体。从CPS的角度全面了解PCN的形成过程是减少PCN排放的前提。由于PCN的毒性和缺乏对活性中间体自由基的精确检测方法，阻碍了从CPS形成PCN的实验。本文以2-氯苯酚(2-CP)为先驱体，通过量子化学计算研究了气相条件下PCN的生成机理。提出了一些具有能量优势的编队路线。用正则变分过渡态理论(CVT)和小曲率隧道贡献(SCT)方法计算了600-1200K温度范围内关键基元步骤的速率常数。这项研究表明，2-CP失去一个氯原子的PCN比没有失去氯原子的PCN更可取。与由2-CP生成PCDF相比，PCN产物的氯化程度较低，生成潜力较低。
Polychlorinated naphthalenes (PCNs) are dioxins-like compounds and are formed along with polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in thermal and combustion procedures. Chlorophenols (CPs) are the most important forerunners of PCNs. A comprehensive comprehension of PCN formation procedure from CPs is a precondition for reducing the discharge of PCNs. Experiments on the formation of PCNs from CPs have been hindered by PCN toxicity and short of precise detection methods for active intermediate radicals. In this work, PCN formation mechanism in gas-phase condition from 2-chlorophenol (2-CP) as forerunner was studied by quantum chemistry calculations. Numbers of energetically advantaged formation routes were proposed. The rate constants of key elementary steps were calculated over 600–1200 K using canonical variational transition-state theory (CVT) with small curvature tunneling contribution (SCT) method. This study illustrates formation of PCNs with one chlorine atom loss from 2-CP is preferred over that without chlorine atom loss. In comparison with formation of PCDFs from 2-CP, PCN products are less chlorinated and have lower formation potential.