title: The OH-initiated atmospheric chemical reactions of polyfluorinated dibenzofurans and polychlorinated dibenzofurans: A comparative theoretical study.
abstract: The atmospheric chemical reactions of some polyfluorinated dibenzofurans (PFDFs) and polychlorinated dibenzofurans (PCDFs), initiated by OH radical, were investigated by performing theoretical calculations using density functional theory (DFT) and B3LYP/6-311++G(2df,p) method. The obtained results indicate that OH addition reactions of PFDFs and PCDFs occurring at C1∼4and CAsites are thermodynamic spontaneous changes and the branching ratio of the PF(C)DF-OH adducts is decided primarily by kinetic factor. The OH addition reactions of PFDFs taking place at fluorinated C1∼4positions are kinetically comparable with those occurring at nonfluorinated C1∼4positions, while OH addition reactions of PCDFs occurring at chlorinated C1∼4sites are negligible. The total rate constants of the addition reactions of PFDFs or PCDFs become smaller with consecutive fluorination or chlorination, and substituting at C1position has more adverse effects than substitution at other sites. The succedent O2addition reactions of PF(C)DF-OH adducts are thermodynamic nonspontaneous processes under the atmospheric conditions, and have high Gibbs free energies of activation (ΔrG≠). The substituted dibenzofuranols are the primary oxidation products for PCDFs under the atmospheric conditions. However, other oxidative products may also be available for PFDFs besides substituted dibenzofuranols.
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China; College of Chemistry and Chemical Engineering, Xinyang Normal University, Henan, Xinyang, 464000, China.
authors: Xiaolan
authors: X
authors: Zeng
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
authors: Jing
authors: J
authors: Chen
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
authors: Ruijuan
authors: R
authors: Qu
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China.
authors: Xiaoxue
authors: X
authors: Pan
authors: State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing, 210023, China. Electronic address: wangzy@nju.edu.cn.
authors: Zunyao
authors: Z
authors: Wang
mesh_terms: D000393:Air Pollutants / Q000737:chemistry*; D000072318:Dibenzofurans / Q000737:chemistry*; D000072338:Dibenzofurans, Polychlorinated / Q000737:chemistry; D004784:Environmental Monitoring; D054879:Halogenation; D017665:Hydroxyl Radical / Q000737:chemistry*; D007700:Kinetics; D008962:Models, Theoretical; D010084:Oxidation-Reduction
chemical_list: D000393:Air Pollutants; D000072318:Dibenzofurans; D000072338:Dibenzofurans, Polychlorinated; D017665:Hydroxyl Radical
keywords: Atmospheric chemical reaction; DFT calculation; OH radical; Polychlorinated dibenzofurans (PCDFs); Polyfluorinated dibenzofurans (PFDFs)