Mechanistic and kinetic study on the reaction of 2;4-dibrominated diphenyl ether (BDE-7) with OH radicals

Cao, Haijie; He, Maoxia; Han, Dandan; Sun, Yanhui; Zhao, Sufang; Ma, Hongjuan; Yao, Shun

doi:10.1016/j.comptc.2011.12.017

Cited by 18 publications

(12 citation statements)

References 40 publications

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“…Compared with the activation energies of elementary reactions, ·OH prefers to add to the phenyl ring with three bromine atoms. This is contrary to the results of 2,4-dibromodiphenyl ether and 2,4,4′-tribromodiphenyl ether, indicating that higher brominated PBDEs have some different properties and should be investigated carefully.…”

Section: Resultscontrasting

confidence: 86%

“…33 Compared with the results of other PBDEs, the rate constants decreased moderately as the degree of bromine substitution of PBDEs increased (Table S4 of the Supporting Information). 36,39,40 The atmospheric lifetime of BDE99 due to tropospheric •OH (1 × 10 6 molecules cm −3 ) is 5.30 × 10 3 hours. The atmospheric lifetime of BDE99 is considerably longer than low brominated congeners (Table S4 of the Supporting Information).…”

Section: Resultsmentioning

confidence: 99%

“…The MPWB1K functional was selected for quantum calculations. In our previous work, , the reliability of this method was proven appropriate (time-saving and accurate) in calculations involving PBDE components. The geometries of all the stable points (reactants, intermediates, and products) and transition states were optimized at the MPWB1 K /6-31+G(d,p) level.…”

Section: Methodsmentioning

confidence: 99%

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Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2′,4,4′,5-Pentabromodiphenyl Ether

Cao

Han

et al. 2015

J. Phys. Chem. A

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This study investigates the decomposition of 2,2',4,4',5-pentabrominated diphenyl ether (BDE99), a commonly detected pollutant in the environment. Debromination channels yielding tetrabrominated diphenyl ethers and hydrogen abstracting aromatic bromine atom formations play significant roles in the reaction of BDE99 + H, in which the former absolutely predominates bimolecular reactions. Polybrominated dibenzo-p-dioxins (PBDDs) and polybrominated dibenzofurans (PBDFs) can be produced during BDE99 pyrolysis, especially for PBDFs under inert conditions. The expected dominant pathways in a closed system are debromination products and PBDF formations. The bimolecular reaction with hydroxyl radical mainly leads to hydroxylated BDE99s rather than hydroxylated tetrabrominated diphenyl ethers. PBDDs are then generated from ortho-hydroxylated PBDEs. HO2 radical reactions rarely proceed. The total rate constants for the BDE99 reaction with hydrogen atoms and hydroxyl radicals exhibit positive dependence on temperature with values of 1.86 × 10(-14) and 5.24 × 10(-14) cm(3) molecule(-1) s(-1) at 298.15 K, respectively.

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Section: Resultscontrasting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2′,4,4′,5-Pentabromodiphenyl Ether

Cao

Han

et al. 2015

J. Phys. Chem. A

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“…All the quantum chemical calculations on the structure, frequency, and energy of related substances such as reactants, products, intermediates, and transition states were performed by using the Gaussian 09 program by using the MPWB1K method [56]. The MPWB1K method is one of the most efficient and high-precision configuration optimization and frequency calculation methods relative to computational cost [57], and has been successfully performed for formation of PCDT/TAs from 2,4-DCTP as precursor [26], formation of polyhalogenated dibenzo-p-dioxins from hydroxylated polybrominated diphenyl ethers [58], atmospheric degradation of 2,3,7,8-TCDD [59,60], and 2,4-dibrominated diphenyl ether [61]. Geometries were optimized at the MPWB1K/6-31+G(d,p) level of theory.…”

Section: Methodsmentioning

confidence: 99%

Quantum Chemical and Kinetic Study on Radical/Molecule Formation Mechanism of Pre-Intermediates for PCTA/PT/DT/DFs from 2-Chlorothiophenol and 2-Chlorophenol Precursors

Zuo

Wang

Pan

et al. 2019

IJMS

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Polychlorinated phenoxathiins (PCPTs), polychlorinated dibenzothiophenes (PCDTs), and polychlorinated thianthrenes (PCTAs) are sulfur analogues of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/DFs). Chlorothiophenols (CTPs) and chlorophenols (CPs) are key precursors for the formation of PCTA/PT/DTs, which can react with H or OH to form chloro(thio)phenoxy radical, sulfydryl/hydroxyl-substituted phenyl radicals, and (thio)phenoxyl diradicals. However, previous radical/radical PCTA/DT formation mechanisms in the literature failed to explain the higher concentration of PCDTs than that of PCTAs under the pyrolysis or combustion conditions. In this work, a detailed thermodynamics and kinetic calculations were carried out to investigate the pre-intermediate formation for PCTA/PT/DTs from radical/molecule coupling of the 2-C(T)P with their key radical species. Our study showed that the radical/molecule coupling mechanism explains the gas-phase formation of PCTA/PT/DTs in both thermodynamic and kinetic perspectives. The S/C coupling modes to form thioether-(thio)enol intermediates are preferable over the O/C coupling modes to form ether-(thio)enol intermediates. Thus, although the radical/molecule coupling of chlorophenoxy radical with 2-C(T)P has no effect on the PCDD/PT formation, the radical/molecule coupling of chlorothiophenoxy radical with 2-C(T)P plays an important role in the PCTA/PT formation. Most importantly, the pre-PCDT intermediates formation pathways from the couplings of sulfydryl/hydroxyl-substituted phenyl radical with 2-C(T)P and (thio)phenoxyl diradicals with 2-C(T)P are more favorable than pre-PCTA/PT intermediates formation pathways from the coupling of chlorothiophenoxy radical with 2-C(T)P, which provides reasonable explanation for the high PCDT-to-PCTA ratio in the environment.

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“…TS was identified with one imaginary frequency. Intrinsic reaction coordinate calculations were performed for each TS to verify the reaction pathways . Single point energies of the optimized structures were calculated at the B3LYP/6‐311++G(3d,2p) level to yield more reliable reaction heat and barrier height values .…”

Section: Methodsmentioning

confidence: 99%

Dimethyl Phthalate Degradation by UV/H₂O₂: Combination of Experimental Methods and Quantum Chemical Calculation

Feng

Guo

et al. 2015

CLEAN Soil Air Water

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Photochemical degradation of typical phthalate esters, as, e.g. dimethyl phthalate (DMP), in water by the UV/H2O2 process was investigated. The degradation rate of DMP was affected by several reaction factors, including initial DMP concentration, H2O2 concentration, UV light intensity, and coexisting cations and anions. The DMP degradation rate decreased with increasing initial DMP concentration. Carbonate ions significantly reduced the reaction rate by 70.2%, while the degradation rate was improved ten‐fold in the presence of ferric ions. The initial reaction mechanism and possible degradation products were investigated using density functional theory (DFT), including B3LYP and M062X hybrid functional. The addition of OH radicals (OH•) to the C4 position of the DMP ring is energetically favored for the initial reaction of DMP with OH•. Dimethyl 4‐hydroxyphthalate (DMP‐4OH) is one of the initial degradation intermediates. A possible reaction mechanism was also proposed based on GC/MS analysis and quantum chemical calculations. The formation of DMP‐4OH has been explained by quantum chemical calculations, which indicates the advantage and promising role of this method in the degradation mechanism analysis.

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Mechanistic and kinetic study on the reaction of 2;4-dibrominated diphenyl ether (BDE-7) with OH radicals

Cited by 18 publications

References 40 publications

Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2′,4,4′,5-Pentabromodiphenyl Ether

Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2′,4,4′,5-Pentabromodiphenyl Ether

Quantum Chemical and Kinetic Study on Radical/Molecule Formation Mechanism of Pre-Intermediates for PCTA/PT/DT/DFs from 2-Chlorothiophenol and 2-Chlorophenol Precursors

Dimethyl Phthalate Degradation by UV/H₂O₂: Combination of Experimental Methods and Quantum Chemical Calculation

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Mechanistic and kinetic study on the reaction of 2;4-dibrominated diphenyl ether (BDE-7) with OH radicals

Cited by 18 publications

References 40 publications

Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2′,4,4′,5-Pentabromodiphenyl Ether

Theoretical Investigation on Mechanistic and Kinetic Transformation of 2,2′,4,4′,5-Pentabromodiphenyl Ether

Quantum Chemical and Kinetic Study on Radical/Molecule Formation Mechanism of Pre-Intermediates for PCTA/PT/DT/DFs from 2-Chlorothiophenol and 2-Chlorophenol Precursors

Dimethyl Phthalate Degradation by UV/H2O2: Combination of Experimental Methods and Quantum Chemical Calculation

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Dimethyl Phthalate Degradation by UV/H₂O₂: Combination of Experimental Methods and Quantum Chemical Calculation