Quantum chemical and kinetic study of formation of 2-chlorophenoxy radical from 2-chlorophenol: unimolecular decomposition and bimolecular reactions with H, OH, Cl, and O2.
Quantum chemical and kinetic study of formation of 2-chlorophenoxy radical from 2-chlorophenol: unimolecular decomposition and bimolecular reactions with H, OH, Cl, and O2.
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DOI：
10.1021/jp712168n
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发表时间：
2008-04
期刊：
影响因子：
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通讯作者：
M. Altarawneh;B. Dlugogorski;E. Kennedy;J. Mackie
中科院分区：
文献类型：
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作者：
M. Altarawneh;B. Dlugogorski;E. Kennedy;J. Mackie
本文研究了多氯二苯并二恶英和多氯二苯并呋喃（PCCD/F）的关键前体2-氯苯酚分子在气相中单分子和双分子反应中生成氯苯氧基自由基的动力学参数。建立了邻氯苯酚单分子分解反应势能面。酚氢向带有氢原子的邻位-C的迁移通过73.6 kcal/mol（0 K）的活化势垒产生2-氯环己-2，4-二烯酮。这条路线比氯或酚氢的直接裂变更重要。计算了2-氯苯酚+ X -> X-H + 2-氯苯氧基（X = H，OH，Cl，O_2）双分子反应的反应速率常数，并与已有的X与苯酚类似反应的实验动力学进行了比较。OH与2-氯苯酚的反应通过直接提取而不是通过加成和随后的水消除产生2-氯苯氧基。本研究的结果将发现在建设详细的动力学模型描述的多氯二苯并对二恶英/F在气相中的形成的应用。
This study investigates the kinetic parameters of the formation of the chlorophenoxy radical from the 2-chlorophenol molecule, a key precursor to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCCD/F), in unimolecular and bimolecular reactions in the gas phase. The study develops the reaction potential energy surface for the unimolecular decomposition of 2-chlorophenol. The migration of the phenolic hydrogen to the ortho-C bearing the hydrogen atom produces 2-chlorocyclohexa-2,4-dienone through an activation barrier of 73.6 kcal/mol (0 K). This route holds more importance than the direct fission of Cl or the phenolic H. Reaction rate constants for the bimolecular reactions, 2-chlorophenol + X --> X-H + 2-chlorophenoxy (X = H, OH, Cl, O2) are calculated and compared with the available experimental kinetics for the analogous reactions of X with phenol. OH reaction with 2-chlorophenol produces 2-chlorophenoxy by direct abstraction rather than through addition and subsequent water elimination. The results of the present study will find applications in the construction of detailed kinetic models describing the formation of PCDD/F in the gas phase.