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Chi TX, Li XX, Ni S, Bai FY, Pan XM, Zhao Z. Theoretical study on the mechanisms, kinetics and risk assessment of OH radicals and Cl atom initiated transformation of HCFC-235fa in the atmosphere. Phys Chem Chem Phys 2024; 26:24821-24832. [PMID: 39290189 DOI: 10.1039/d4cp02323d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/19/2024]
Abstract
Hydrochlorofluorocarbons (HCFCs) are important greenhouse gases and ozone-depleting substances. Thus, a thorough understanding of their atmospheric fate is essential for preventing and controlling atmospheric pollution. Herein, the atmospheric transformation mechanism of CF3CH2CClF2 (HCFC-235fa) by the OH radical and the Cl atom was carried out at the dual-level of CCSD(T)/aug-cc-pVTZ//M06-2X/6-311+G(d,p). The reaction rate coefficients were calculated using the multistructural canonical variational transition state theory with small curvature tunneling (MS-CVT/SCT) at 200-1000 K. The kMS-CVT/SCT(CF3CH2CClF2 + OH) and kMS-CVT/SCT(CF3CH2CClF2 + Cl) values are 9.05 × 10-15 and 1.95 × 10-17 cm3 molecule-1 s-1 at 297 K, respectively. The results show that the role of OH is more important than Cl in the degradation of CF3CH2CClF2. The atmospheric lifetimes (83 days-77.93 years), ozone destruction potential (0.001-0.023), and global warming potentials (GWP100 = 21.06-5157.35) of CF3CH2CClF2 were assessed, and these results indicate that CF3CH2CClF2 is atmospherically persistent and environmentally unfriendly. The evolution mechanisms of CF3C·HCClF2, CF3C(OO˙)HCClF2, and CF3C(O˙)HCClF2 in the presence of O2, HO2˙, and NO were investigated and discussed. The resulting products of CF3CH2CClF2 are mostly highly oxidized multi-functional compounds in the forms of aldehydes, ketones, and organic nitrates. A computational assessment of acute and chronic toxicities was performed at three levels of nutrition in order to improve the understanding of the potential toxicity of CF3CH2CClF2 and its degradation products to the aquatic environment. The acidification potential of CF3CH2CClF2 was calculated to be 1.141 and presumed to contribute to the formation of acid rain. The results may contribute to describing HCFCs' atmospheric fate, persistence, and environmental risks.
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Affiliation(s)
- Tai-Xing Chi
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, People's Republic of China.
| | - Xin-Xin Li
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, People's Republic of China.
| | - Shuang Ni
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, People's Republic of China.
| | - Feng-Yang Bai
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, People's Republic of China.
- Key Laboratory of Cluster Science, Ministry of Education of China, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing 100081, People's Republic of China
| | - Xiu-Mei Pan
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, People's Republic of China.
| | - Zhen Zhao
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang 110034, People's Republic of China.
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Chang Ping, Beijing 102249, People's Republic of China
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Mechanistic and kinetic insights into the atmospheric degradation of (CH3)3CF and (CH3)3CCl initiated by Cl atom. COMPUT THEOR CHEM 2022. [DOI: 10.1016/j.comptc.2022.113807] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Bai FY, Deng MS, Chen MY, Kong L, Ni S, Zhao Z, Pan XM. Atmospheric oxidation of fluoroalcohols initiated by ˙OH radicals in the presence of water and mineral dusts: mechanism, kinetics, and risk assessment. Phys Chem Chem Phys 2021; 23:13115-13127. [PMID: 34075970 DOI: 10.1039/d1cp01324f] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The transport and formation of fluorinated compounds are greatly significant due to their possible environmental risks. In this work, the ˙OH-mediated degradation of CF3CF2CF2CH2OH and CF3CHFCF2CH2OH in the presence of O2/NO/NO2 was studied by using density functional theory and the direct kinetic method. The formation mechanisms of perfluorocarboxylic/hydroperfluorocarboxylic acids (PFCAs/H-PFCAs), which were produced from the reactions of α-hydroxyperoxy radicals with NO/NO2 and the ensuing oxidation of α-hydroxyalkoxy radicals, were clarified and discussed. The roles of water and silica particles in the rate constants and ˙OH reaction mechanism with fluoroalcohols were investigated theoretically. The results showed that water and silica particles do not alter the reaction mechanism but obviously change the kinetic properties. Water could retard fluoroalcohol degradation by decreasing the rate constants by 3-5 orders of magnitude. However, the heterogeneous ˙OH-rate coefficients on the silica particle surfaces, including H4SiO4, H6Si2O7, and H12Si6O18, are larger than that of the naked reaction by 1.20-24.50 times. This finding suggested that these heterogeneous reactions may be responsible for the atmospheric loss of fluoroalcohols and the burden of PFCAs. In addition, fluoroalcohols could be exothermically trapped by H12Si6O18, H6Si2O7, and H4SiO4, in which the chemisorption on H12Si6O18 is stronger than that on H6Si2O7 or H4SiO4. The global warming potentials and radiative forcing of CF3CF2CF2CH2OH/CF3CHFCF2CH2OH were calculated to assess their contributions to the greenhouse effect. The toxicities of individual species were also estimated via the ECOSAR program and experimental measurements. This work enhances the understanding of the environmental formation of PFCAs and the transformation of fluoroalcohols.
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Affiliation(s)
- Feng-Yang Bai
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Ming-Shuai Deng
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Mei-Yan Chen
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Lian Kong
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China.
| | - Shuang Ni
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
| | - Zhen Zhao
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, P. R. China. and State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Chang Ping, Beijing 102249, P. R. China
| | - Xiu-Mei Pan
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
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Bai FY, Ni S, Tang YZ, Pan XM, Zhao Z. Ciprofloxacin transformation in aqueous environments: Mechanism, kinetics, and toxicity assessment during •OH-mediated oxidation. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 699:134190. [PMID: 31670037 DOI: 10.1016/j.scitotenv.2019.134190] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 08/27/2019] [Accepted: 08/28/2019] [Indexed: 06/10/2023]
Abstract
The initial reactions of organics with •OH are important to understand their transformations and fates in advanced oxidation processes in aqueous phase. Herein, the kinetics and mechanism of •OH-initiated degradation of ciprofloxacin (CIP), an antibiotic of fluoroquinolone class, are obtained using density functional and computational kinetics methods. All feasible mechanisms are considered, including H-abstraction, •OH-addition, and sequential electron proton transfer. Results showed that the H-abstraction is the dominant reaction pathway, and the product radicals P7H, P9H, and P10H are the dominating intermediates. The aqueous phase rate coefficients for the •OH-triggered reaction of ciprofloxacin are calculated from 273 K to 323 K to examine the temperature dependent effect, and the theoretical value of 6.07 × 109 M-1 s-1 at 298 K is close to the corresponding experimental data. Moreover, the intermediates P7H, P9H, and P10H could easily transform to several stable products in the presence of O2, HO2•, and •OH. The peroxy radical, which is generated from the incorporation of H-abstraction product radicals (P7H, P9H, and P10H) with O2, prefers to produce HO2• into the surrounding through direct concerted elimination rather than the indirect mechanism. In addition, the peroxy radical could react with HO2• via triplet and singlet routes, and the former is more favorable due to its smaller barrier compared with the latter. The hydroxyl-substituted CIP has higher activity than its parent compound in their reactions with •OH due to its lower barrier and faster rate. In addition, the -NHC(O)-containing compound IM3-P10-H-4 is harmful to aquatic fish and is the primary product in the •OH-rich environment according to the ecotoxicity assessment computations. This study can improve our comprehension on CIP transformation in complex water environments.
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Affiliation(s)
- Feng-Yang Bai
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, People's Republic of China
| | - Shuang Ni
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, People's Republic of China
| | - Yi-Zhen Tang
- School of Environmental and Municipal Engineering, Qingdao Technological University, Qingdao 266033, People's Republic of China
| | - Xiu-Mei Pan
- National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, Changchun 130024, People's Republic of China.
| | - Zhen Zhao
- Institute of Catalysis for Energy and Environment, College of Chemistry and Chemical Engineering, Shenyang Normal University, Shenyang, Liaoning 110034, People's Republic of China
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Li MY, Bai FY, Pan XM. Theoretical study of H-atom abstraction reactions from CH3CH2OCH2CH3, CHF2CF2OCH2CF3 and CF3CH2OCH3 by NO3 radical & subsequent degradation. J Mol Graph Model 2019; 93:107453. [DOI: 10.1016/j.jmgm.2019.107453] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/14/2019] [Accepted: 09/16/2019] [Indexed: 11/28/2022]
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Gour NK, Rajkumari NP, Deka RC, Paul S, Deka A. Atmospheric degradation pathways and kinetics of 2,2-difluoroethanol (CHF2CH2OH) with Cl atom: A theoretical investigation. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2018.11.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Ma Y, Jia ZM, Bai FY, Pan XM, Zhao L. Theoretical study on the formation mechanisms, dynamics and the effective catalysis of the nitrophenols. ChemistrySelect 2018. [DOI: 10.1002/slct.201802006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yuan Ma
- Institute of Functional Material Chemistry; National & Local United Engineering Lab for Power Battery; Faculty of Chemistry; Northeast Normal University, 130024, Changchun, People's Republic of; China
| | - Zi-man Jia
- Civil and Environmental Engineering; Henry Samueli School of Engineering and Applied Science; University of California, Los Angeles, California; 90095 United States
| | - Feng-yang Bai
- Institute of Functional Material Chemistry; National & Local United Engineering Lab for Power Battery; Faculty of Chemistry; Northeast Normal University, 130024, Changchun, People's Republic of; China
| | - Xiu-mei Pan
- Institute of Functional Material Chemistry; National & Local United Engineering Lab for Power Battery; Faculty of Chemistry; Northeast Normal University, 130024, Changchun, People's Republic of; China
| | - Liang Zhao
- Institute of Functional Material Chemistry; National & Local United Engineering Lab for Power Battery; Faculty of Chemistry; Northeast Normal University, 130024, Changchun, People's Republic of; China
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Baidya B, Lily M, Chandra AK. Theoretical Insight into the Kinetics of H-Abstraction Reaction of CHF 2
CH 2
OH with OH Radical, Atmospheric Lifetime and Global Warming Potential. ChemistrySelect 2018. [DOI: 10.1002/slct.201800491] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Bidisha Baidya
- Centre for Advanced Studies in Chemistry; North-Eastern Hill University; Shillong 793 022 India
| | - Makroni Lily
- Centre for Advanced Studies in Chemistry; North-Eastern Hill University; Shillong 793 022 India
| | - Asit K. Chandra
- Centre for Advanced Studies in Chemistry; North-Eastern Hill University; Shillong 793 022 India
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Bai FY, Lv S, Ma Y, Liu CY, He CF, Pan XM. Understanding the insight into the mechanisms and dynamics of the Cl-initiated oxidation of (CH 3) 3CC(O)X and the subsequent reactions in the presence of NO and O 2 (X = F, Cl, and Br). CHEMOSPHERE 2017; 171:49-56. [PMID: 28002766 DOI: 10.1016/j.chemosphere.2016.12.037] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/07/2016] [Accepted: 12/08/2016] [Indexed: 06/06/2023]
Abstract
In this work, the density functional and high-level ab initio theories are adopted to investigate the mechanisms and kinetics of reaction of (CH3)3CC(O)X (X = F, Cl, and Br) with atomic chlorine. Rate coefficients for the reactions of chlorine atom with (CH3)3CC(O)F (k1), (CH3)3CC(O)Cl (k2), and (CH3)3CC(O)Br (k3) are calculated using canonical variational transition state theory coupled with small curvature tunneling method over a wide range of temperatures from 250 to 1000 K. The dynamic calculations are performed by the variational transition state theory with the interpolated single-point energies method at the CCSD(T)/aug-cc-pVDZ//B3LYP/6-311++G(d,p) level of theory. Computed rate constant is in good line with the available experimental value. The rate constants for the title reactions are in this order: k1<k2<k3, suggesting that the effect of halogen substitution on the mechanisms and dynamics is different. The subsequent and secondary reactions for the hydrogen abstraction intermediates are studied involving NO and O2 molecules in the atmosphere. The atmospheric lifetime and global warming potential (GWP) of (CH3)3CC(O)X (X = F, Cl, and Br) are estimated, and it shows that (CH3)3CC(O)F have larger GWP value than that of (CH3)3CC(O)Cl and (CH3)3CC(O)Br. Due to the presence of Cl and Br atoms, the environmental impact of (CH3)3CC(O)Cl and (CH3)3CC(O)Br may be given more concerns.
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Affiliation(s)
- Feng-Yang Bai
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China
| | - Shuang Lv
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China
| | - Yuan Ma
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China
| | - Chun-Yu Liu
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China
| | - Chun-Fang He
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China
| | - Xiu-Mei Pan
- Institute of Functional Material Chemistry, National & Local United Engineering Lab for Power Battery, Faculty of Chemistry, Northeast Normal University, 130024, Changchun, People's Republic of China.
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Ye JT, Bai FY, Shi SQ, Pan XM. Computational exploration of regioselectivity and atmospheric lifetime in NO 3-initiated reactions of CH 3OCH 3 and CH 3OCH 2CH 3. J Mol Graph Model 2017; 72:156-167. [PMID: 28092834 DOI: 10.1016/j.jmgm.2017.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Revised: 12/20/2016] [Accepted: 01/03/2017] [Indexed: 10/20/2022]
Abstract
The NO3-initiated reactions of CH3OCH3 and CH3OCH2CH3 have been investigated by the BHandHLYP method in conjunction with the 6-311G(d,p) basis set. Thermodynamic and kinetic data are further refined using the comparatively accurate CCSD(T) method. According to the values of reaction enthalpies (ΔHr,298θ) and reaction Gibbs free energies (ΔGr,298θ) from CH3OCH2CH3 with NO3 system, we find that H-abstraction pathway from the α-CH2 group is more exothermic. It is further confirmed by the calculated CH bond dissociation energy of CH3OCH2CH3 molecule. All the rate constants, computed through means of canonical variational transition state with small-curvature tunneling correction, are fitted to the three-parameter expressions k1=1.54×10-23T3.34exp(-1035.53/T) and k2=3.55×10-26T4.31exp(-281.24/T)cm3molecule-1s-1 and branching ratios are computed over the temperature range 200-600K. The branching ratios are also discussed. The atmospheric lifetimes of CH3OCH3 and CH3OCH2CH3 determined by the NO3 radical are about 270 and 29days, respectively.
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Affiliation(s)
- Jin-Ting Ye
- Institute of Faculty of Chemistry, National & Local United Engineering Lab for Power Battery Northeast Normal University, 130024 Changchun, People's Republic of China
| | - Feng-Yang Bai
- Institute of Faculty of Chemistry, National & Local United Engineering Lab for Power Battery Northeast Normal University, 130024 Changchun, People's Republic of China
| | - Shao-Qing Shi
- Institute of Faculty of Chemistry, National & Local United Engineering Lab for Power Battery Northeast Normal University, 130024 Changchun, People's Republic of China
| | - Xiu-Mei Pan
- Institute of Faculty of Chemistry, National & Local United Engineering Lab for Power Battery Northeast Normal University, 130024 Changchun, People's Republic of China.
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