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

Rashidian, Nooshin; Zahedi, Ehsan; Shiroudi, Abolfazl

doi:10.1016/j.scitotenv.2019.05.056

Cited by 18 publications

(7 citation statements)

References 41 publications

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“…M06-2X functional has been widely used in theoretical calculation and can be better for ionic hydrogen-bonding interactions and identifying the global minimum conformer. [29][30][31][32][33][34][35][36] Been considered as the "gold standard" of quantum chemistry, CCSD(T) method was widely been used for reactions of organic matters and has high level accuracy. Thus we choose M06-2X functional at the 6-311++G(d,p) basis set for geometrical structures optimization and CCSD(T) method with the aug-cc-pVTZ basis set for single point energy calculation in this paper.…”

Section: Methodsmentioning

confidence: 99%

A theoretical study on the formation and oxidation mechanism of hydroxyalkylsulfonate in the atmospheric aqueous phase

Zhang

Sun

et al. 2019

RSC Adv.

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Section: Methodsmentioning

confidence: 99%

A theoretical study on the formation and oxidation mechanism of hydroxyalkylsulfonate in the atmospheric aqueous phase

Zhang

Sun

et al. 2019

RSC Adv.

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“…The Lennard‐Jones potential parameters σ =3.68 Å, ϵ / k B =86.6 K [31] for dry air as carrier gas and σ =5.40 Å, ϵ / k B =608.6 K for PRC yield the Lennard‐Jones collisional frequency 4.79×10 −10 cm 3 molecule −1 s −1 . All unimolecular rate constants at 760 Torr are in fall‐off region indicating that CTST rates for the conversion of PRC will be unreliable.…”

Section: Resultsmentioning

confidence: 99%

DFT Insight into the Kinetics and Mechanism of the OH^.‐Initiated Atmospheric Oxidation of Catechol: OH^. Addition and Hydrogen Abstraction Pathways

et al. 2021

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Gas phase oxidation of catechol with hydroxyl radical is expected as dominant atmospheric removal process. The mechanism and kinetics of OH.‐initiated atmospheric oxidation of catechol was investigated theoretically by employing of M06‐2X/aug‐cc‐pVTZ level of theory at 300 K and 760 Torr by considering of OH. addition and H‐atom abstraction reactions. Oxidation of catechol begins with reversible formation of pre‐reactive molecular complex and its conversion to products in unimolecular manner. Fall‐off pressure expression indicated that canonical transition state theory breaks down to estimate rate constant at 760 Torr. RRKM unimolecular rates were corrected for basis set superposition error and quantum tunneling effects. RRKM bimolecular rates for OH. addition and H‐atom abstraction pathways at 300 K and 760 Torr were about 10−12 cm3 molecule−1 s−1. The RRKM bimolecular rate for oxidation of catechol triggered by OH. at 300 K and 760 Torr was 9.45×10−12 cm3 molecule−1 s−1 and its temperature dependence over 200–400 K can be expressed by the lnk=(2929.8/T)+(5.82×10−16), indicating that reaction rate is negatively dependent on the temperature. H‐atom abstraction from the hydroxy group at the C2 position and addition of OH. onto the C2 atom are the most favorable processes. Evolution of branching ratios demonstrate that the OH.‐initiated oxidation of catechol is not essentially selective process.

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“…Since the change of entropy for reverse reaction (VdW i to MeSa+OH) is more than the reaction of VdW i to P i . The expression of overall rate constant is written as [49,50] : where K C,i is equilibrium constant for reaction of

M e S a ⟷ V d W_{i}

where i=1 to 4, and

k_{v d w_{i} \to_{}^{i = 1 t o 4} P_{i (i = 1 t o 6)}}

is the unimolecular rate constant for conversion of VdW i to P i (i=1 to 6) that is obtained from RRKM calculations. The values of the rate constant of k MeSa→Pi (i=1 to 6) are given in the Table 7.…”

Section: Resultsmentioning

confidence: 99%

Atmospheric Oxidation Reactions of Methyl Salicylate as Green Leaf Volatiles by OH Radical: Theoretical Kinetics and Mechanism

et al. 2020

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Green leaf volatile (GLV) organic compounds, released from vegetation, act as plants’ multifunctional weapon and are known to be a source of secondary organic aerosols (SOAs). In the present study, the mechanism of oxidation reaction of methyl salicylate (MeSa), a known GLV, by OH radical has been investigated by means of density functional theory (DFT). Canonical transition state (CTST) and Rice‐Ramsperger‐Kassel‐Marcus theories (RRKM) with Wigner and Eckart tunneling correction were applied to calculate the transition pressure, the total rate constant, and the individual rate constants for every channel of this oxidation reaction of MeSa with OH radical. The calculated overall bimolecular rate constant with Eckart tunneling correction for the title reaction is 1.18×109 and 1.01×109 L mol−1s−1 at Mn15‐L/aug‐cc‐pVTZ and MN15‐L/MG3S levels of theory in the gas phase at 298 K which is comparable to the experimental reported value of 6.66×109 L mol−1s−1, indicating that the results of MN15‐L/aug‐cc‐pVTZ level of theory is more accurate. Investigation of transition pressure and fall‐off curve of unimolecular channels at proposed mechanism for oxidation reaction of MeSa revealed that the TST breaks down slightly to estimate the high pressure limit of reaction rate and the reaction become second order (bimolecular reaction). Furthermore, the atmospheric lifetime of MeSa is about 2.95 and 3.44 days calculated at those two levels of theory, respectively, which indicates that MeSa can be considered as a medium‐lifetime organic volatile compound.

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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

Cited by 18 publications

References 41 publications

A theoretical study on the formation and oxidation mechanism of hydroxyalkylsulfonate in the atmospheric aqueous phase

A theoretical study on the formation and oxidation mechanism of hydroxyalkylsulfonate in the atmospheric aqueous phase

DFT Insight into the Kinetics and Mechanism of the OH^.‐Initiated Atmospheric Oxidation of Catechol: OH^. Addition and Hydrogen Abstraction Pathways

Atmospheric Oxidation Reactions of Methyl Salicylate as Green Leaf Volatiles by OH Radical: Theoretical Kinetics and Mechanism

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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

Cited by 18 publications

References 41 publications

A theoretical study on the formation and oxidation mechanism of hydroxyalkylsulfonate in the atmospheric aqueous phase

A theoretical study on the formation and oxidation mechanism of hydroxyalkylsulfonate in the atmospheric aqueous phase

DFT Insight into the Kinetics and Mechanism of the OH.‐Initiated Atmospheric Oxidation of Catechol: OH. Addition and Hydrogen Abstraction Pathways

Atmospheric Oxidation Reactions of Methyl Salicylate as Green Leaf Volatiles by OH Radical: Theoretical Kinetics and Mechanism

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DFT Insight into the Kinetics and Mechanism of the OH^.‐Initiated Atmospheric Oxidation of Catechol: OH^. Addition and Hydrogen Abstraction Pathways