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Kinetic and mechanistic insight into the OH-initiated atmospheric oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin via OH-addition and hydrogen abstraction pathways: A theoretical investigation.

Abstract

The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic polychlorinated dibenzo-p-dioxin. The OH-initiated oxidation of TCDD has been studied using the density functional, canonical transition state, and canonical Rice-Ramsperger-Kassel-Marcus theories. The kinetic data were corrected for quantum tunneling by the Wigner and Eckart models. All OH addition and hydrogen atom abstraction channels were thermodynamically exergonic. The kinetic and thermodynamic data analysis at the reliable level MPWB1K/MG3S//M06-2X/MG3S indicate that the addition of OH to the carbon atom adjacent to the oxygen atom in dioxin ring leads to the formation of predominant adduct. The calculated bimolecular rate constant for the formation of predominant adduct was ~5.97-6.75 × 10-13 cm3 molecule-1 s-1, its branching ratio was ~0.955, and the overall rate constant for the OH-initiated oxidation of TCDD was ~6.25-7.08 × 10-13 cm3 molecule-1 s-1. The atmospheric lifetime of TCDD determined by OH was ~8.17-9.26 days indicating the TCDD can be categorized as medium lifetime organic pollutant.

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  • Authors+Show Affiliations

    ,

    Department of Chemistry, Shahrood Branch, Islamic Azad University, Shahrood, Iran.

    ,

    Department of Chemistry, Shahrood Branch, Islamic Azad University, Shahrood, Iran. Electronic address: e_zahedi@iau-shahrood.ac.ir.

    Young Researchers and Elite Club, East Tehran Branch, Islamic Azad University, Tehran, Iran.

    Source

    The Science of the total environment 679: 2019 Aug 20 pg 106-114

    Pub Type(s)

    Journal Article

    Language

    eng

    PubMed ID

    31082585

    Citation

    Rashidian, Nooshin, et al. "Kinetic and Mechanistic Insight Into the OH-initiated Atmospheric Oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin Via OH-addition and Hydrogen Abstraction Pathways: a Theoretical Investigation." The Science of the Total Environment, vol. 679, 2019, pp. 106-114.
    Rashidian N, Zahedi E, Shiroudi A. Kinetic and mechanistic insight into the OH-initiated atmospheric oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin via OH-addition and hydrogen abstraction pathways: A theoretical investigation. Sci Total Environ. 2019;679:106-114.
    Rashidian, N., Zahedi, E., & Shiroudi, A. (2019). Kinetic and mechanistic insight into the OH-initiated atmospheric oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin via OH-addition and hydrogen abstraction pathways: A theoretical investigation. The Science of the Total Environment, 679, pp. 106-114. doi:10.1016/j.scitotenv.2019.05.056.
    Rashidian N, Zahedi E, Shiroudi A. Kinetic and Mechanistic Insight Into the OH-initiated Atmospheric Oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin Via OH-addition and Hydrogen Abstraction Pathways: a Theoretical Investigation. Sci Total Environ. 2019 Aug 20;679:106-114. PubMed PMID: 31082585.
    * Article titles in AMA citation format should be in sentence-case
    TY - JOUR T1 - Kinetic and mechanistic insight into the OH-initiated atmospheric oxidation of 2,3,7,8-tetrachlorodibenzo-p-dioxin via OH-addition and hydrogen abstraction pathways: A theoretical investigation. AU - Rashidian,Nooshin, AU - Zahedi,Ehsan, AU - Shiroudi,Abolfazl, Y1 - 2019/05/07/ PY - 2019/02/13/received PY - 2019/05/03/revised PY - 2019/05/05/accepted PY - 2019/5/15/pubmed PY - 2019/5/15/medline PY - 2019/5/15/entrez KW - CTST KW - DFT KW - OH–initiated oxidation KW - RRKM KW - TCDD SP - 106 EP - 114 JF - The Science of the total environment JO - Sci. Total Environ. VL - 679 N2 - The 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is the most toxic polychlorinated dibenzo-p-dioxin. The OH-initiated oxidation of TCDD has been studied using the density functional, canonical transition state, and canonical Rice-Ramsperger-Kassel-Marcus theories. The kinetic data were corrected for quantum tunneling by the Wigner and Eckart models. All OH addition and hydrogen atom abstraction channels were thermodynamically exergonic. The kinetic and thermodynamic data analysis at the reliable level MPWB1K/MG3S//M06-2X/MG3S indicate that the addition of OH to the carbon atom adjacent to the oxygen atom in dioxin ring leads to the formation of predominant adduct. The calculated bimolecular rate constant for the formation of predominant adduct was ~5.97-6.75 × 10-13 cm3 molecule-1 s-1, its branching ratio was ~0.955, and the overall rate constant for the OH-initiated oxidation of TCDD was ~6.25-7.08 × 10-13 cm3 molecule-1 s-1. The atmospheric lifetime of TCDD determined by OH was ~8.17-9.26 days indicating the TCDD can be categorized as medium lifetime organic pollutant. SN - 1879-1026 UR - https://www.unboundmedicine.com/medline/citation/31082585/Kinetic_and_mechanistic_insight_into_the_OH-initiated_atmospheric_oxidation_of_2,3,7,8-tetrachlorodibenzo-p-dioxin_via_OH-addition_and_hydrogen_abstraction_pathways:_A_theoretical_investigation L2 - https://linkinghub.elsevier.com/retrieve/pii/S0048-9697(19)32067-4 DB - PRIME DP - Unbound Medicine ER -