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Nguyen TL, Peeters J. The CH(X 2Π) + H 2O reaction: two transition state kinetics. Phys Chem Chem Phys 2021; 23:16142-16149. [PMID: 34296725 DOI: 10.1039/d1cp02234b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The reaction of ground state methylidyne (CH) with water vapor (H2O) is theoretically re-investigated using high-level coupled cluster computations in combination with semi-classical transition state theory (SCTST) and two-dimensional master equation simulations. Insertion of CH into a H-O bond of H2O over a submerged barrier via a well-skipping mechanism yielding solely H and CH2O is characterized. The reaction kinetics is effectively determined by the formation of a pre-reaction van der Waals complex (PRC, HC-OH2) and its subsequent isomerization to activated CH2OH in competition with PRC re-dissociation. The tunneling effects are found to be minor, while variational effects in the PRC → CH2OH step are negligible. The calculated rate coefficient k(T) is nearly pressure-independent, but strongly depends on temperature with pronounced down-up behavior: a high value of 2 × 10-10 cm3 s-1 at 50 K, followed by a fairly steep decrease down to 8 × 10-12 cm3 s-1 at 900 K, but increasing again to 5 × 10-11 cm3 s-1 at 3500 K. Over the T-range of this work, k(T) can be expressed as: k(T, P = 0) = 2.31 × 10-11 (T/300 K)-1.615 exp(-38.45/T) cm3 s-1 for T = 50-400 K k(T, P = 0) = 1.15 × 10-12 (T/300 K)0.8637 exp(892.6/T) cm3 s-1 for T = 400-1000 K k(T, P = 0) = 4.57 × 10-15 (T/300 K)3.375 exp(3477.4/T) cm3 s-1 for T = 1000-3500 K.
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Affiliation(s)
- Thanh Lam Nguyen
- Quantum Theory Project, Department of Chemistry and Physics, University of Florida, Gainesville, FL 32611, USA.
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Theoretical investigation of the CS + OH → Products reaction on an interpolated potential energy surface: reaction dynamic and chemical kinetic insights. Struct Chem 2020. [DOI: 10.1007/s11224-020-01574-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Seif A, Domingo LR, Ahmadi TS. Calculation of the rate constants for hydrogen abstraction reactions by Hydroperoxyl radical from Methanol, and the investigation of stability of CH3OH.HO2 complex. COMPUT THEOR CHEM 2020. [DOI: 10.1016/j.comptc.2020.113010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Masoumpour MS, Daryanavard M. Ab Initio-Based Global Potential Energy Surface and Reaction Dynamics for H 2S + C. J Phys Chem A 2020; 124:7901-7910. [DOI: 10.1021/acs.jpca.0c05856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - Marzieh Daryanavard
- Department of chemistry, Estahban Higher Education Center, Estahban 74519-44655, Iran
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Mazarei E, Hosein Mousavipour S. Theoretical Study on the Dynamics and Kinetics of the Reaction of CH 2OH with OH. J Phys Chem A 2018; 122:9761-9777. [PMID: 30508487 DOI: 10.1021/acs.jpca.8b09621] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The stochastic one-dimensional chemical master equation (CME) simulation method was used to investigate the dynamics of the reaction of CH2OH with OH. A multiwell multichannel potential energy surface (PES) was constructed at the CCSD(T)/Aug-cc-pVTZ//CBS-QB3 and QCISD(T)/Aug-cc-pVTZ//CBS-QB3 levels of theory. The constructed PES consisted of three chemically activated intermediates and two van der Waals complexes. The fractional population analysis unraveled the role of the energized intermediates and van der Waals complexes in the early stages of this complex reaction. The CME calculations provided the phenomenological rate constants through analysis of the eigenvalues and eigenvectors of collision matrices while Leonard-Jones potential was used to model the collisions. The CME results indicated that CH2O and H2O were the major products, in accordance with the literature. Also, the findings declared the temperature and pressure independence of the reaction over a wide range of temperature (250 to 2400 K) and pressure (0.1 to 7 atm). Furthermore, the efficiency of tunneling on the hydrogen transfer isomerization reaction of trans-HCOH to CH2O was confirmed over the temperature range of 250 to 3000 K. The rate constants for different reaction channels are reported.
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Affiliation(s)
- Elham Mazarei
- Department of Chemistry, College of Science , Shiraz University , Shiraz , Iran
| | - S Hosein Mousavipour
- Department of Chemistry, College of Science , Shiraz University , Shiraz , Iran.,Department of Chemistry, Faculty of Science , Sultan Qaboos University , Muscat , Sultanate of Oman
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Wang W, Feng W, Wang W, Li P. Theoretical Investigations on the Reactivity of Methylidyne Radical toward 2,3,7,8-Tetrachlorodibenzo- p-Dioxin: A DFT and Molecular Dynamics Study. Molecules 2018; 23:E2685. [PMID: 30340385 PMCID: PMC6222546 DOI: 10.3390/molecules23102685] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 12/22/2022] Open
Abstract
To explore the potential reactivity of the methylidyne radical (CH) toward 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), the reaction mechanism between them has been systematically investigated employing the density functional theory (DFT) and ab initio molecular dynamics simulations. The relevant thermodynamic and kinetic parameters in the possible reaction pathways have been discussed as well as the IR spectra and hyperfine coupling constants (hfcc's) of the major products. Different from the reaction of the CH radical with 2,3,7,8-tetrachlorodibenzofuran, CH radical can attack all the C-C bonds of TCDD to form an initial intermediate barrierlessly via the cycloaddition mechanism. After then, the introduced C-H bond can be further inserted into the C-C bond of TCDD, resulting in the formation of a seven-membered ring structure. The whole reactions are favorable thermodynamically and kinetically. Moreover, the major products have been verified by ab initio molecular dynamics simulations. The distinct IR spectra and hyperfine coupling constants of the major products can provide some help for their experimental detection and identification. In addition, the reactivity of the CH radical toward the F- and Br-substituted TCDDs has also been investigated. Hopefully, the present findings can provide new insights into the reactivity of the CH radical in the transformation of TCDD-like dioxins.
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Affiliation(s)
- Weihua Wang
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Wenling Feng
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Wenliang Wang
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, China.
| | - Ping Li
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu 273165, China.
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Zhang X, Yang M, Sun X, Wang X, Wang Y. The experimental observation, mechanism and kinetic studies on the reaction of hexachloro-1,3-butadiene initiated by typical atmospheric oxidants. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 627:256-263. [PMID: 29426148 DOI: 10.1016/j.scitotenv.2018.01.163] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Revised: 01/11/2018] [Accepted: 01/17/2018] [Indexed: 06/08/2023]
Abstract
Hexachloro-1,3-butadiene (HCBD) is a persistent organic pollutant in the environment. When its samples were collected and observed, the levels of HCBD in its source and high mountains are higher than in urban cities, oil factories and countryside. The density functional theory is applied to the degradation mechanism of HCBD with Cl, NO3, HO2, OH and O3. Those reactions are optimized and calculated at two carbon sites of double bonds, and then the subsequent reactions of the OH-initiated intermediates with O2 and NO are taken as examples. Ozonization reactions of HCBD including the formation of primary and secondary ozonides are investigated. The Criegee intermediates created in the ozonization reactions can react with O2, SO2, NO2 and H2O. Reaction rate constants of the Cl, NO3, HO2, OH and O3 initiated reactions with HCBD are calculated within 200 to 400 K with the transition state theory method, and the rate constants of the Cl, NO3, HO2, OH and O3 at 298.15 K are 4.51 × 10-13, 1.32 × 10-20, 4.33 × 10-29, 6.33 × 10-16, 5.80 × 10-27 cm3 molecule-1 s-1, respectively. The reactions of OH and Cl radicals with HCBD are more important than those of NO3, HO2 and O3 according to the reaction rate branching ratio. Both the temperature and reaction rate could change with the height.
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Affiliation(s)
- Xianghe Zhang
- Environment Research Institute, Shandong University, Jinan 250100, PR China
| | - Minmin Yang
- School of Environment Science and Engineering, Shandong University, Jinan 250100, PR China
| | - Xiaomin Sun
- Environment Research Institute, Shandong University, Jinan 250100, PR China.
| | - Xiaolei Wang
- Shandong Normal University, Jinan 250014, PR China
| | - Yan Wang
- School of Environment Science and Engineering, Shandong University, Jinan 250100, PR China.
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Wei W, Wang W, Xu K, Feng W, Li X, Li P. Theoretical insights into the reaction mechanisms between 2,3,7,8-tetrachlorodibenzofuran and the methylidyne radical. RSC Adv 2018; 8:21150-21163. [PMID: 35539902 PMCID: PMC9080895 DOI: 10.1039/c8ra03046d] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Accepted: 06/03/2018] [Indexed: 11/21/2022] Open
Abstract
To explore the potential role of the methylidyne radical (CH) in the transformation of 2,3,7,8-tetrachlorodibenzofuran (TCDF), in this study, the detailed reaction mechanisms between TCDF and CH radical have been systematically investigated employing the B3LYP method of density functional theory (DFT) in combination with the atoms in molecules (AIM) theory and ab initio molecular dynamics. It was found that the title reaction is a multi-channel reaction, i.e., the CH radical can attack the C-X (X = C, Cl, H, O) bonds of TCDF via the insertion modes, resulting in the formation of 13 products. Thermodynamically, the whole reaction processes are exothermic and spontaneous since all the enthalpy and Gibbs free energy changes are negative values in the formation processes. Moreover, the thermodynamic stability of the products is controlled by the distribution of the single unpaired electron. Kinetically, the most favorable reaction channel is the insertion of the CH radical into the C-C bond except for the C atoms attached to the chlorine atom. Moreover, the dominant products have been further confirmed by the molecular dynamics. Meanwhile, the IR spectra and hyperfine coupling constants of the dominant products have been investigated to provide helpful information for their identification experimentally. In addition, the reactivity of the CH radical toward the F- and Br-substituted TCDFs has also been investigated. Expectedly, the present findings can enable us to better understand the reactivity of the CH radical toward organic pollutants analogous to TCDF in the atmosphere.
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Affiliation(s)
- Wenjing Wei
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University Qufu 273165 P. R. China
| | - Weihua Wang
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University Qufu 273165 P. R. China
| | - Kaining Xu
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University Qufu 273165 P. R. China
| | - Wenling Feng
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University Qufu 273165 P. R. China
| | - Xiaoping Li
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University Qufu 273165 P. R. China
| | - Ping Li
- Key Laboratory of Life-Organic Analysis, School of Chemistry and Chemical Engineering, Qufu Normal University Qufu 273165 P. R. China
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