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Nguyen LT, Mai TVT, Vien HD, Nguyen TT, Huynh LK. Ab initio kinetics of the CH 3NH + NO 2 reaction: formation of nitramines and N-alkyl nitroxides. Phys Chem Chem Phys 2023; 25:31936-31947. [PMID: 37974519 DOI: 10.1039/d3cp03333c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2023]
Abstract
This study provides a detailed understanding of how the reaction between CH3NH, one of the primary products of the CH3NH2 + OH/Cl reactions, and NOx occurs in the atmosphere since the reaction is expected to be a dominant sink for the tropospheric CH3NH radical. First, we focus on the reaction of the aminyl radical CH3NH with NO2, complementing the known reaction between CH3NH and NO, to provide the overall picture of the CH3NH + NOx system. The reaction was meticulously examined across the extended range of temperature (298-2000 K) and pressure (0.76-76 000 torr) using quantum chemistry calculations and kinetic modeling based on the framework of the Rice-Ramsperger-Kassel-Marcus (RRKM)-based master equation. Highly correlated electronic structure calculations unveil that the intricate reaction mechanism of the CH3NH + NO2 reaction, which can proceed through O-addition or N-addition to form NO2, encompasses numerous steps, channels, and various intermediates and products. The temperature-/pressure-dependent kinetic behaviors and product distribution of the CH3NH + NO2 reaction are revealed under atmospheric and combustion conditions. The main products under atmospheric conditions are found to be CH3NHO and NO, as well as CH3NHNO2, while under combustion conditions, the primary products are only CH3NHO and NO. Given its stability under ambient conditions, CH3NHNO2, a nitramine, is believed to have the potential to induce DNA damage, which can ultimately result in severe cancers. Secondly, by building upon prior research on the CH3NH + NO system, this study shows that the reaction of CH3NH with NOx holds greater importance in urban areas with elevated NOx emissions than other oxidants like O2. Furthermore, this reaction occurs swiftly and results in the creation of various compounds, such as the carcinogenic nitrosamine (CH3NHNO), carcinogenic nitramine (CH3NHNO2), CH3NNOH, (CH3NN + H2O) and (CH3NHO + NO).
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Affiliation(s)
- Loc T Nguyen
- School of Chemical and Environmental Engineering, International University, Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam.
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Tam V-T Mai
- Institute of Fundamental and Applied Sciences, Duy Tan University, 06 Tran Nhat Duat, Tan Dinh Ward, District 1, Ho Chi Minh City, Vietnam
- Faculty of Natural Sciences, Duy Tan University, Da Nang City, Vietnam
| | - Huy D Vien
- School of Chemical and Environmental Engineering, International University, Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam.
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Trang T Nguyen
- School of Chemical and Environmental Engineering, International University, Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam.
- Vietnam National University, Ho Chi Minh City, Vietnam
| | - Lam K Huynh
- School of Chemical and Environmental Engineering, International University, Quarter 6, Linh Trung Ward, Thu Duc City, Ho Chi Minh City, Vietnam.
- Vietnam National University, Ho Chi Minh City, Vietnam
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Niu S, Wu X, Hou Q, Luo G, Qu W, Zhao F, Wang G, Zhang F. Theoretical Kinetic Studies on Thermal Decomposition of Glycerol Trinitrate and Trimethylolethane Trinitrate in the Gas and Liquid Phases. J Phys Chem A 2023; 127:1283-1292. [PMID: 36715586 DOI: 10.1021/acs.jpca.2c07282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glycerol trinitrate (NG) and trimethylolethane trinitrate (TMETN), as typical nitrate esters, are important energetic plasticizers in solid propellants. With the aid of high-precision quantum chemical calculations, the Rice-Ramsperger-Kassel-Marcus (RRKM)/master equation theory and the transition state theory have been employed to investigate the decomposition kinetics of NG and TMETN in the gas phase (over the temperature range of 300-1000 K and pressure range of 0.01-100 atm) and liquid phase (using water as the solvent). The continuum solvation model based on solute electron density (SMD) was used to describe the solvent effect. The thermal decomposition mechanism is closely relevant to the combustion properties of energetic materials. The results show that the RO-NO2 dissociation channel overwhelmingly favors other reaction pathways, including HONO elimination for the decomposition of NG and TMETN in both the gas phase and liquid phase. At 500 K and 1 atm, the rate coefficient of gas phase decomposition of TMETN is 5 times higher than that of NG. Nevertheless, the liquid phase decomposition of TMETN is a factor of 5835 slower than that of NG at 500 K. The solvation effect caused by vapor pressure and solubility can be used to justify such contradictions. Our calculations provide detailed mechanistic evidence for the initial kinetics of nitrate ester decomposition in both the gas phase and liquid phase, which is particularly valuable for understanding the multiphase decomposition behavior and building detailed kinetic models for nitrate ester.
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Affiliation(s)
- Shiyao Niu
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui230029, China.,Science and Technology on Combustion and Explosion Laboratory, Xi'an Modern Chemistry Research Institute, Xi'an, Shaanxi710065, China.,Heifei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui230029, China
| | - Xiaoqing Wu
- Heifei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui230029, China.,College of Information Engineering, China Jiliang University, Hangzhou, Zhejiang310018, China
| | - Qifeng Hou
- Heifei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui230029, China
| | - Guangda Luo
- Heifei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui230029, China
| | - Wengang Qu
- Science and Technology on Combustion and Explosion Laboratory, Xi'an Modern Chemistry Research Institute, Xi'an, Shaanxi710065, China
| | - Fengqi Zhao
- Science and Technology on Combustion and Explosion Laboratory, Xi'an Modern Chemistry Research Institute, Xi'an, Shaanxi710065, China
| | - Gongming Wang
- School of Chemistry and Materials Science, University of Science and Technology of China, Hefei, Anhui230029, China
| | - Feng Zhang
- Heifei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui230029, China
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Zhao H, Wang S, Sun J, Zhang Y, Tang Y. OH-initiated degradation of 1,2,3-trimethylbenzene in the atmosphere and wastewater: Mechanisms, kinetics, and ecotoxicity. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 857:159534. [PMID: 36272473 DOI: 10.1016/j.scitotenv.2022.159534] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 06/16/2023]
Abstract
1,2,3-Trimethylbenzene (1,2,3-TMB) is an important volatile organic compound (VOC) present in petroleum wastewater and the atmosphere. This compound can be degraded by OH radicals via abstraction, addition and substitution mechanisms. Results show that the addition mechanism is dominant and H-abstraction is subdominant, while methyl abstraction and substitution mechanisms are negligible in the gas and aqueous phases. Moreover, H-abstraction products undergo further reactions with O2, NO, NO2, H2O, and OH radicals in the atmosphere. Time-dependent density functional theory (TDDFT) calculations show that the degraded products, including 2,3,4-trimethylphenyl-nitroperoxoite, 1,2,3-trimethyl-4-nitrobenzene, 1,2,3-trimethyl-5-nitrobenzene, 2,6-dimethylbenzyl nitroperoxoite, 2,3-dimethylphenyl nitroperoxoite, 2,6-dimethylbenzaldehyde, and 2,3-dimethylbenzaldehyde, can photolyze under the sunlight. Kinetically, the calculated total rate constant is 5.57 × 10-11 cm3 molecule-1·s-1 at 1 atm and 298 K, which is consistent with available experimental values measured in the atmosphere. In addition, the calculated total reaction rate constant in water is close to that in the gas phase. In terms of ecotoxicity, all degradation products are less toxic than the initial reactant to fish, green algae and daphnia. For mammals represented by rats, 1,2,3-TMB and its products are moderately toxic, except for 2,3-dimethylphenol and 2,6-dimethylphenol, which are slightly toxic.
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Affiliation(s)
- Hui Zhao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong 266033, PR China
| | - Shuangjun Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong 266033, PR China
| | - Jingyu Sun
- College of Chemistry and Environmental Engineering, Hubei Normal University, Cihu Road 11, Huangshi, Hubei 435002, PR China
| | - Yunju Zhang
- College of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang 621000, PR China
| | - Yizhen Tang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong 266033, PR China.
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Zhao H, Sun J, Zhang Y, Wang S, Lu C, Tang Y, Guan J, Pan Y. Investigations on mechanisms, kinetics, and ecotoxicity in OH-initiated degradation of 1,2,4,5-tetramethylbenzene in the environment. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:84616-84628. [PMID: 35788481 DOI: 10.1007/s11356-022-21704-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/23/2022] [Indexed: 06/15/2023]
Abstract
As one of the volatile organic compounds (VOCs) in the environment, 1,2,4,5-tetramethylbenzene (1,2,4,5-TeMB) present in oily wastewater, and it can occur substitution, abstraction, and addition reactions with OH radicals in the atmosphere and wastewater. Electrostatic potential (ESP) and average local ionization energy (ALIE) prediction indicate that H atoms from CH3 group and the benzene ring are the most active sites in 1,2,4,5-TeMB. The result shows that potential energy surfaces (PESs) in the gas and aqueous phase are similar, and the relevant barriers in the latter one are higher. The dominant channel is H abstraction from the benzene ring, and the subdominant one is OH radical addition to the benzene ring. Furthermore, subsequent reactions of dominant products with O2, NO2, NO, and OH radicals in the atmosphere are studied, as well. The total reaction rate constant is calculated to be 2.36×10-10 cm3 molecule-1 s-1 at 1 atm and 298 K in the atmosphere, which agrees well with the experimental data. While the total rate constant in the aqueous phase is much lower than that in the gas phase. Ecologic toxicity analysis shows that 1,2,4,5-TeMB is very toxic to fish, daphnia, and green algae; and OH-initiated degradation in the environment will reduce its toxicity.
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Affiliation(s)
- Hui Zhao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, People's Republic of China
| | - Jingyu Sun
- College of Chemistry and Environmental engineering, Hubei Normal University, Cihu Road 11, Huangshi, Hubei, 435002, People's Republic of China
| | - Yunju Zhang
- College of Chemistry and Chemical Engineering, Mianyang Normal University, Mianyang, 621000, People's Republic of China
| | - Shuangjun Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, People's Republic of China
| | - Chenggang Lu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, People's Republic of China
| | - Yizhen Tang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, People's Republic of China.
| | - Jing Guan
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, People's Republic of China
| | - Yaru Pan
- College of Chemistry, Tonghua Normal University, Tonghua, 134002, People's Republic of China
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Zhao H, Wang S, Sun J, Lu C, Tang Y. A new theoretical investigation on ·OH initiated oxidation of acephate in the environment: mechanism, kinetics, and toxicity. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2022; 24:1912-1922. [PMID: 36156666 DOI: 10.1039/d2em00254j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Acephate (O,S-dimethyl acetylphosphoramidothioate) is a typical organophosphorus pesticide used widely in agriculture. It can be released into the atmosphere and water during production and application. In this work, mechanisms in the ·OH initiated degradation of acephate were investigated using quantum chemical methods. Results show that addition, substitution and H-abstraction mechanisms can take place, with the latter being dominant. Moreover, the subsequent reactions of dominant products with O2 and NO in the atmosphere were considered, as well. The rate constant in the atmosphere and aqueous phase was calculated by transition state theory (TST) with the Wigner tunneling contribution. The total rate constant in the atmosphere and aqueous phase is 7.86 × 10-10 and 1.83 × 10-12 cm3 per molecule per s, respectively, the latter being in accordance with the available experimental value of 1.50 × 10-12 cm3 per molecule per s. Moreover, the ecotoxicity of acephate and degradation products was assessed in fish, daphnia, green algae and rats.
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Affiliation(s)
- Hui Zhao
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, PR China.
| | - Shuangjun Wang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, PR China.
| | - Jingyu Sun
- College of Chemistry and Environmental Engineering, Hubei Normal University, Cihu Road 11, Huangshi, Hubei, 435002, PR China
| | - Chenggang Lu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, PR China.
| | - Yizhen Tang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Fushun Road 11, Qingdao, Shandong, 266033, PR China.
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Feng B, Sun C, Zhao W, Zhang S. A theoretical investigation on the atmospheric degradation of the radical: reactions with NO, NO 2, and NO 3. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1554-1565. [PMID: 32608429 DOI: 10.1039/d0em00112k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The radical is the key intermediate in the atmospheric oxidation of benzaldehyde, and its further chemistry contributes to local air pollution. The reaction mechanisms of the radical with NO, NO2, and NO3 were studied by quantum chemistry calculations at the CCSD(T)/CBS//M06-2X/def2-TZVP level of theory. The explicit potential energy curves were provided in order to reveal the atmospheric fate of the radical comprehensively. The main products of the reaction of with NO are predicted to be , CO2 and NO2. The reaction of with NO2 is reversible, and its main product would be C6H5C(O)O2NO2 which was predicted to be more stable than PAN (peroxyacetyl nitrate) at room temperature. The decomposition of C6H5C(O)O2NO2 at different ambient temperatures would be a potential long-range transport source of NOx in the atmosphere. The predominant products of the reaction are predicted to be C6H5C(O)O2H, C6H5C(O)OH, O2 and O3, while HO˙ is of minor importance. So, the reaction of with would be an important source of ozone and carboxylic acids in the local atmosphere, and has less contribution to the regeneration of HO˙ radicals. The reaction of with NO3 should mainly produce , CO2, O2 and NO2, which might play an important role in atmospheric chemistry of peroxy radicals at night, but has less contribution to the night-time conversion of ( and RO˙) to ( and HO˙) in the local atmosphere. The results above are in good accordance with the reported experimental observations.
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Affiliation(s)
- Bo Feng
- School of Chemistry and Chemical Engineering, Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, South Zhongguancun Street # 5, Haidian District, Beijing, 100081, P. R. China.
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Mai TVT, Huynh LK. Ab initio kinetics of the C 2H 2 + NH 2 reaction: a revisited study. Phys Chem Chem Phys 2019; 21:17232-17239. [PMID: 31347629 DOI: 10.1039/c9cp02258a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This work provides a rigorous detailed kinetic study on the C2H2 + NH2 reaction in a wide range of conditions (T = 250-2000 K & P = 1-76000 Torr). In particular, the composite method W1U was used to construct the potential energy surface on which the kinetic behaviors were characterized within the state-of-the-art master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) framework. Corrections of the hindered internal rotation (HIR) treatment and quantum tunneling effect were included. A clear reaction mechanism shift with respect to both temperature and pressure was revealed via detailed kinetic and species analyses. In particular, bimolecular products (i.e., CH2[double bond, length as m-dash]C[double bond, length as m-dash]NH + H, CH[triple bond, length as m-dash]CNH2 + H, CH3CN + H, CH[triple bond, length as m-dash]C· + NH3 in the decreasing mole fraction order) can be formed directly from the reactants at high temperature and/or low pressure while they can be produced indirectly via intermediates (e.g., ·CH[double bond, length as m-dash]CHNH2(cis), ·CH[double bond, length as m-dash]CHNH2(trans), CH2[double bond, length as m-dash]C·NH2,…) at low temperature and/or high pressure. The calculated rate constants are in good agreement with the literature data from ab initio calculations without any adjustment; thus, the proposed temperature- and pressure-dependent rate constants, together with the thermodynamic data of the species involved, can be confidently used for modeling NH2-related systems under atmospheric and combustion conditions.
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Affiliation(s)
- Tam V-T Mai
- Molecular Science and Nano-Materials Lab, Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City, Vietnam. and University of Science, Vietnam National University - HCMC, 227 Nguyen Van Cu, Ward 4, District 5, Ho Chi Minh City, Vietnam
| | - Lam K Huynh
- International University, Vietnam National University - HCMC, Quarter 6, Linh Trung Ward, Thu Duc District, Ho Chi Minh City, Vietnam.
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Mai TVT, Nguyen HT, Huynh LK. Ab initio dynamics of hydrogen abstraction from N2H4 by OH radicals: an RRKM-based master equation study. Phys Chem Chem Phys 2019; 21:23733-23741. [DOI: 10.1039/c9cp04585f] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The detailed kinetic mechanism of the N2H4 + OH reaction is comprehensively reported for a wide condition range of conditions (i.e., 200–3000 K & 1–7600 Torr) using the CCSD(T)/CBS//M06-2X/6-311++G(3df,2p) level and the RRKM-based master equation rate model.
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Affiliation(s)
- Tam V.-T. Mai
- Molecular Science and Nano-Materials Lab
- Institute for Computational Science and Technology
- Ho Chi Minh City
- Vietnam
- University of Science
| | - Hieu T. Nguyen
- Molecular Science and Nano-Materials Lab
- Institute for Computational Science and Technology
- Ho Chi Minh City
- Vietnam
| | - Lam K. Huynh
- International University
- Vietnam National University – HCMC
- Ho Chi Minh City
- Vietnam
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Mai TVT, Duong MV, Nguyen HT, Huynh LK. Ab initio kinetics of the HOSO 2 + 3O 2 → SO 3 + HO 2 reaction. Phys Chem Chem Phys 2018; 20:6677-6687. [PMID: 29457181 DOI: 10.1039/c7cp07704a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The detailed kinetic mechanism of the HOSO2 + 3O2 reaction, which plays a pivotal role in the atmospheric oxidation of SO2, was investigated using accurate electronic structure calculations and novel statistical thermodynamic/kinetic models. Explored using the accurate composite method W1U, the detailed potential energy surface (PES) revealed that the addition of O2 to a HOSO2 radical to form the adduct (HOSO4) proceeds via a transition state with a slightly positive barrier (i.e., 0.7 kcal mol-1 at 0 K). Such a finding compromises a long-term hypothesis about this channel of being a barrierless process. Moreover, the overall reaction was found to be slightly exothermic by 1.7 kcal mol-1 at 0 K, which is in good agreement with recent studies. On the newly-constructed PES, the temperature- and pressure-dependent behaviors of the title reaction were characterized in a wide range of conditions (T = 200-1000 K & P = 10-760 Torr) using the integrated deterministic and stochastic master equation/Rice-Ramsperger-Kassel-Marcus (ME/RRKM) rate model in which corrections for hindered internal rotation (HIR) and tunneling treatments were included. The calculated numbers were found to be in excellent agreement with literature data. The sensitivity analyses on the derived rate coefficients with respect to the ab initio input parameters (i.e., barrier height and energy transfer) were also performed to further understand the kinetic behaviors of the title reaction. The detailed kinetic mechanism, consisting of thermodynamic and kinetic data (in NASA polynomial and modified Arrhenius formats, respectively), was also provided at different T & P for further use in the modeling/simulation of any related systems.
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Affiliation(s)
- Tam V-T Mai
- Molecular Science and Nano-Materials Lab, Institute for Computational Science and Technology, SBI Building, Quang Trung Software City, Tan Chanh Hiep Ward, District 12, Ho Chi Minh City, Vietnam
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