Quantum chemistry study on the destruction mechanism of 2,3,7,8-TCDD by OH and O3 radicals

Wen, Zhengcheng; Wang, Zhihua; Xu, Jiangrong; Liu, Yang; Cen, Kefa

doi:10.1016/j.chemosphere.2013.03.027

Cited by 6 publications

(6 citation statements)

References 25 publications

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“…In other cases, DFT methods have also been used to obtain the electronic energies: restricted Kohn–Sham methods included B3LYP − (by far, the most used method), M11, MPW1PW91, MPW1K, ,, BB1K, M06-2X, and BH&HLYP . Less frequently, unrestricted, spin-contaminated DFT methods were used (for example, UB3LYP or UM11). Only a few gas-phase studies were concerned with molecules other than olefins.…”

Section: Introductionmentioning

confidence: 99%

Gas-Phase Ozone Reactions with a Structurally Diverse Set of Molecules: Barrier Heights and Reaction Energies Evaluated by Coupled Cluster and Density Functional Theory Calculations

2019

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Reactions with ozone transform organic and inorganic molecules in water treatment systems as well as in atmospheric chemistry, either in the aqueous phase, at gas/ particle interfaces, or in the gas phase. Computed thermokinetic data can be used to estimate the reactivities of molecules toward ozone in cases where no experimental data are available. Although the gas-phase reactivity of olefins with ozone has been characterized extensively in the literature, this is not the case for the richer chemistry of ozone with polar molecules, which occurs in the aqueous phase or in microhydrated environments. Here, we selected a number of model reactions with small molecules (ethene, ethyne, hydrogen cyanide, hydrogen chloride, ammonia, bromide, and trimethylamine) to study the accuracy of different quantum chemical methods for describing the reactivities of these molecules with ozone. We calculated benchmark electronic energies of gas-phase reactions of these systems with singlereference coupled cluster (CC) theory. These benchmark results for the binding energy in the van der Waals complex, the energy of the transition structure, and the reaction energy were estimated to be accurate within 1−2 kcal mol −1 . Singlet oxygen ( 1 O 2 ) is a common product of ozone reactions. Coupled cluster calculations with up to perturbative quadruples (CCSDT(Q)) were needed to obtain reaction energies accurate within 1 kcal mol −1 when this species was involved. In (micro)hydrated environments or at interfaces, coupled cluster methods are prohibitively expensive in most cases. We tested the suitability of some contemporary density functional theory (DFT) methods to reproduce the benchmark electronic energy differences. Range-separated functionals were found to be promising candidates to estimate forward barrier heights, with LC-ωPBE rivaling the accuracy of CCSD(T). For energies of reaction, however, DFT methods exhibited large systematic errors, depending on their fraction of orbital exchange. This was found to worsen when 1 O 2 is a product, and no safe recommendation can be given for DFT reaction energies in such cases.

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Section: Introductionmentioning

confidence: 99%

Gas-Phase Ozone Reactions with a Structurally Diverse Set of Molecules: Barrier Heights and Reaction Energies Evaluated by Coupled Cluster and Density Functional Theory Calculations

2019

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“…The investigation of these compounds' reactivity in different environments is of great interest to understand their degradation, which will allow the development of new treatment processes and a better understanding of the toxic effect on the environment and health. In the last decade, the reactivity of organochlorides and in particular the different enantiomers of the DDT, TCDD and PCBs, have been investigated through computational approach [28][29][30][31][32][33][34] . The degradation processes were investigated from molecular dynamics simulation on the DDT in a water-sediment environment, and several studies have implemented atmospheric reactions initiated by radicals such as OH, CH or molecules such as O 3 and H 2 O 2 .…”

Section: Please Cite This Article As Doi:101063/50120831mentioning

confidence: 99%

Development of a novel ReaxFF reactive potential for organochloride molecules

Wolf

Bégué

Vallverdu

2022

The Journal of Chemical Physics

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This article presents a new reactive potential in the ReaxFF formalism. It aims to include the chlorine element, and opens up the fields of use of ReaxFF to the whole class of organochloride compounds including conjugated or aromatic groups. Numerous compounds in this family raise global awareness due to their environmental impact, and such a reactive potential will help investigate their degradation pathways. The new force field belongs to the aqueous branch. The force field parameters were fitted against high-level quantum chemistry calculations, including CASSCF/NEVPT2 calculations and density functional theory calculations, and its accuracy was evaluated using a validation set. The root means square deviation against quantum mechanics energies is 0.38 eV (8.91 kcal/mol). From a structural point of view, the root means square deviation is about 0.06Å for the bond lengths, 11.86{degree sign} for the angles and 4.12{degree sign} for the dihedral angles. With CHONCl-2022_weak new force field, we successfully investigated the regioselectivity for nucleophilic or electrophilic attacks on polychlorinated biphenyls (PCB), which are toxic and permanent pollutants. The rotation barriers along the bond linking the two benzene rings, which is crucial in the toxicity of these compounds, are well reproduced by CHONCl-2022_weak. Then our new reactive potential is used to investigate the chlorobenzene atmospheric oxidation, initiated by a hydroxyl radical. The reaction pathways computed with ReaxFF agree with the quantum mechanics results. We showed that, in the presence of dioxygen molecules, the oxidation of chlorobenzene likely leads to the formation of highly oxygenated compounds after the abstraction of hydrogen radicals.

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“…[9] A variety of computational studies on formation and decomposition processes of CDDs and CDF, for example, is readily available in the literature. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Two major formation mechanisms of CDDs and CDFs have been proposed in the literature: [9,22] Homogenous gas-phase formation from structurally similar precursors and the heterogenous de novo synthesis route from carbon matrices in fly ash. The presence of metals, such as copper and copper oxides, has been found to catalyze both routes.…”

Section: Introductionmentioning

confidence: 99%

A Reactive Molecular Dynamics Study of Chlorinated Organic Compounds. Part II: A ChemTraYzer Study of Chlorinated Dibenzofuran Formation and Decomposition Processes

et al. 2023

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In our two-paper series, we first present the development of ReaxFF CHOCl parameters using the recently published ParAMS parametrization tool. In this second part, we update the reactive Molecular Dynamics -Quantum Mechanics coupling scheme ChemTraYzer and combine it with our new ReaxFF parameters from Part I to study formation and decomposition processes of chlorinated dibenzofurans. We introduce a self-learning method for recovering failed transition-state searches that improves the overall ChemTraYzer transition-state search success rate by 10 percentage points to a total of 48 %. With ChemTraYzer, we automatically find and quantify more than 500 reactions using transition state theory and DFT. Among the discovered chlorinated dibenzofuran reactions are numerous reactions that are new to the literature. In three case studies, we discuss the set of reactions that are most relevant to the dibenzofuran literature: (i) bimolecular reactions of the chlorinated-dibenzofuran precursors phenoxy radical and 1,3,5-trichlorobenzene, (ii) dibenzofuran chlorination and pyrolysis, and (iii) oxidation of chlorinated dibenzofurans.

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Quantum chemistry study on the destruction mechanism of 2,3,7,8-TCDD by OH and O3 radicals

Cited by 6 publications

References 25 publications

Gas-Phase Ozone Reactions with a Structurally Diverse Set of Molecules: Barrier Heights and Reaction Energies Evaluated by Coupled Cluster and Density Functional Theory Calculations

Gas-Phase Ozone Reactions with a Structurally Diverse Set of Molecules: Barrier Heights and Reaction Energies Evaluated by Coupled Cluster and Density Functional Theory Calculations

Development of a novel ReaxFF reactive potential for organochloride molecules

A Reactive Molecular Dynamics Study of Chlorinated Organic Compounds. Part II: A ChemTraYzer Study of Chlorinated Dibenzofuran Formation and Decomposition Processes

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