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Sulbaek Andersen MP, Nielsen OJ, Sherman JD. Assessing the potential climate impact of anaesthetic gases. Lancet Planet Health 2023; 7:e622-e629. [PMID: 37438003 DOI: 10.1016/s2542-5196(23)00084-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 07/14/2023]
Abstract
There is increasing concern within the health-care community about the role care delivery plays in environmental degradation, sparking research into how to reduce pollution from clinical practice. Inhaled anaesthetics is a particular research area of interest for two reasons. First, several gases are potent greenhouse gases, and waste gas is mostly emitted directly to the environment. Second, there are options to reduce gas waste and substitute medications and procedures with fewer embodied emissions while delivering high-quality care. Performance improvements are contingent on a proper understanding of the emission estimates and climate metrics used to ensure consistent application in guiding mitigation strategies and accounting at various scales. We review the current literature on the environmental impact and the estimation of the potential climate forcing of common inhaled anaesthetic drugs: desflurane, sevoflurane, isoflurane, methoxyflurane, and nitrous oxide.
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Affiliation(s)
- Mads Peter Sulbaek Andersen
- Department of Chemistry and Biochemistry, California State University Northridge, Northridge, CA, USA; Copenhagen Center for Atmospheric Research, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark.
| | - Ole John Nielsen
- Copenhagen Center for Atmospheric Research, Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Jodi D Sherman
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
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Junxi L, Bomiao Q, Mengmeng L, Fupeng Z, Fang R, Zhibin L, Shaofeng P, Shujuan M, Yanbin W, Qiong S. Insights into selectivity of some oxygen containing gases by the CHCl •– anion from molecular simulation. MOLECULAR SIMULATION 2023. [DOI: 10.1080/08927022.2023.2189983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2023]
Affiliation(s)
- Liang Junxi
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Qi Bomiao
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, People’s Republic of China
| | - Lu Mengmeng
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Zhang Fupeng
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Ren Fang
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Lu Zhibin
- State Key Laboratory of Solid Lubrication, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou, People’s Republic of China
| | - Pang Shaofeng
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Meng Shujuan
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Wang Yanbin
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
| | - Su Qiong
- Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Gansu Provincial Biomass Function Composites Engineering Research Center, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, College of Chemical Engineering, Northwest Minzu University, Lanzhou, People’s Republic of China
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Paul S, Mishra BK, Baruah SD, Deka RC, Gour NK. Atmospheric oxidation of HFE-7300 [n-C 2F 5CF(OCH 3)CF(CF 3) 2] initiated by •OH/Cl oxidants and subsequent degradation of its product radical: a DFT approach. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2020; 27:907-920. [PMID: 31820248 DOI: 10.1007/s11356-019-06975-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 11/05/2019] [Indexed: 06/10/2023]
Abstract
To understand the atmospheric chemistry of hydrofluoroethers, we have studied the oxidation of a highly fluorinated compound n-C2F5CF(OCH3)CF(CF3)2 (HFE-7300) by OH/Cl oxidants. Here, we have employed M06-2X functional along with a 6-31 + G(d,p) basis set to obtain the optimized structures, various forms of energies, and different modes of frequencies for all species. We have characterized energies of all species on the potential energy surface, and it indicates that H-abstraction from n-C2F5CF(OCH3)CF(CF3)2 by Cl atom is kinetically more dominant than the H-abstraction reaction initiated by OH radical. In contrast, the calculated energy change (ΔrH°298 and ΔrG°298) results govern that OH-initiated H-abstraction reaction is highly exothermic and spontaneous compared to the Cl-initiated H-abstraction reaction. Rate constants are estimated using transition state theory as well as canonical variation transition state theory at the temperature range 200-1000 K and 1 atm pressure. The calculated rate constants of the H-abstraction channels are found to be in good agreement with the reported experimental rate constant at 298 K. Moreover, we have estimated the atmospheric lifetimes of HFE-7300 for the reaction with OH radical and Cl atom and are found to be 1.75 and 153.93 years, respectively. Additionally, the global warming potentials for HFE-7300 molecule are also estimated for 20-, 100-, and 500-year time horizons. Further, subsequent aerial oxidation of product radical (n-C2F5CF(OCH2)CF(CF3)2) in the presence of NO radical is performed, and it produced alkoxy radical via formation of peroxy radical. This alkoxy radical undergoes unimolecular decompositions via two different ways and formed n-C2F5CF(OCHO)CF(CF3)2 and n-C2F5CF(OH) CF(CF3)2 products.
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Affiliation(s)
- Subrata Paul
- Department of Chemical Sciences, Tezpur University Tezpur, Tezpur, Assam, 784028, India
| | - Bhupesh Kumar Mishra
- Department of Chemistry, D. N. Government College, Itanagar, Arunachal Pradesh, 791113, India
| | - Satyajit Dey Baruah
- Department of Chemical Sciences, Tezpur University Tezpur, Tezpur, Assam, 784028, India
| | - Ramesh Chandra Deka
- Department of Chemical Sciences, Tezpur University Tezpur, Tezpur, Assam, 784028, India
| | - Nand Kishor Gour
- Department of Chemical Sciences, Tezpur University Tezpur, Tezpur, Assam, 784028, India.
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Hass SA, Andersen ST, Sulbaek Andersen MP, Nielsen OJ. Atmospheric Chemistry of Methoxyflurane (CH3OCF2CHCl2): Kinetics of the gas-phase reactions with OH radicals, Cl atoms and O3. Chem Phys Lett 2019. [DOI: 10.1016/j.cplett.2019.02.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Ponnusamy S, Sandhiya L, Senthilkumar K. Atmospheric Oxidation Mechanism and Kinetics of Hydrofluoroethers, CH3OCF3, CH3OCHF2, and CHF2OCH2CF3, by OH Radical: A Theoretical Study. J Phys Chem A 2018; 122:4972-4982. [DOI: 10.1021/acs.jpca.8b01890] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- S. Ponnusamy
- Department of Physics, Bharathiar University, Coimbatore 641 046, India
| | - L. Sandhiya
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409, United States
| | - K. Senthilkumar
- Department of Physics, Bharathiar University, Coimbatore 641 046, India
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Ren H, Li X. Theoretical investigation on H abstraction reaction mechanisms and rate constants of Isoflurane with the OH radical. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1051152] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sauer F, Portmann RW, Ravishankara AR, Burkholder JB. Temperature dependence of the Cl atom reaction with deuterated methanes. J Phys Chem A 2015; 119:4396-407. [PMID: 25470739 DOI: 10.1021/jp508721h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Kinetic isotope effect (KIE) and reaction rate coefficients, k1-k4, for the gas-phase reaction of Cl atoms with (12)CH3D (k1), (12)CH2D2 (k2), (12)CHD3 (k3), and (12)CD4 (k4) over the temperature range 223-343 K in 630 Torr of synthetic air are reported. Rate coefficients were measured using a relative rate technique with (12)CH4 as the primary reference compound. Fourier transform infrared spectroscopy was used to monitor the methane isotopologue loss. The obtained KIE values were (12)CH3D: KIE1(T) = (1.227 ± 0.004) exp((43 ± 5)/T); (12)CH2D2: KIE2(T) = (1.14 ± 0.20) exp((191 ± 60)/T); (12)CHD3: KIE3(T) = (1.73 ± 0.34) exp((229 ± 60)/T); and (12)CD4: KIE4(T) = (1.01 ± 0.3) exp((724 ± 19)/T), where KIEx(T) = kCl+(12)CH4(T)/kx(T). The quoted uncertainties are at the 2σ (95% confidence) level and represent the precision of our data. The following Arrhenius expressions and 295 K rate coefficient values (in units of cm(3) molecule(-1) s(-1)) were derived from the above KIE using a rate coefficient of 7.3 × 10(-12) exp(-1280/T) cm(3) molecule(-1) s(-1) for the reaction of Cl with (12)CH4: k1(T) = (5.95 ± 0.70) × 10(-12) exp(-(1323 ± 50)/T), k1(295 K) = (6.7 ± 0.8) × 10(-14); k2(T) = (6.4 ± 1.3) × 10(-12) exp(-(1471 ± 60)/T), k2(295 K) = (4.4 ± 0.9) × 10(-14); k3(T) = (4.2 ± 1.0) × 10(-12) exp(-(1509 ± 60)/T), k3(295 K) = (2.53 ± 0.6) × 10(-14); and k4(T) = (7.13 ± 2.3) × 10(-12) exp(-(2000 ± 120)/T), k4(295 K) = (0.81 ± 0.26) × 10(-14). The reported uncertainties in the pre-exponential factors are 2σ and include estimated systematic errors in our measurements and the uncertainty in the reference reaction rate coefficient. The results from this study are compared with previously reported room-temperature rate coefficients for each of the deuterated methanes as well as the available temperature dependent data for the Cl atom reactions with CH3D and CD4. A two-dimensional atmospheric chemistry model was used to examine the implications of the present results to the atmospheric lifetime and vertical variation in the loss of the deuterated methane isotopologues. The relative contributions of the reactions of OH, Cl, and O((1)D) to the loss of the isotopologues in the stratosphere were also examined. The results of the calculations are described and discussed.
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Affiliation(s)
- Frank Sauer
- †Chemical Sciences Division, Earth System Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, Colorado 80305, United States.,‡Cooperative Institutes for Research in Environmental Sciences, University of Colorado, Boulder, Colorado 80309, United States
| | - Robert W Portmann
- †Chemical Sciences Division, Earth System Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, Colorado 80305, United States
| | - A R Ravishankara
- †Chemical Sciences Division, Earth System Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, Colorado 80305, United States
| | - James B Burkholder
- †Chemical Sciences Division, Earth System Laboratory, National Oceanic and Atmospheric Administration, 325 Broadway, Boulder, Colorado 80305, United States
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Singh HJ, Tiwari L, Rao PK. Computational Study on OH and Cl Initiated Oxidation of 2,2,2-Trifluoroethyl Trifluoroacetate (CF3C(O)OCH2CF3). B KOREAN CHEM SOC 2014. [DOI: 10.5012/bkcs.2014.35.5.1385] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Singh HJ, Gour NK, Rao PK, Tiwari L. Theoretical investigation on the kinetics and branching ratio of the gas phase reaction of sevoflurane with Cl atom. J Mol Model 2013; 19:4815-22. [DOI: 10.1007/s00894-013-1977-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2013] [Accepted: 08/21/2013] [Indexed: 10/26/2022]
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Sulbaek Andersen MP, Nielsen OJ, Karpichev B, Wallington TJ, Sander SP. Atmospheric chemistry of isoflurane, desflurane, and sevoflurane: kinetics and mechanisms of reactions with chlorine atoms and OH radicals and global warming potentials. J Phys Chem A 2012; 116:5806-20. [PMID: 22146013 DOI: 10.1021/jp2077598] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The smog chamber/Fourier-transform infrared spectroscopy (FTIR) technique was used to measure the rate coefficients k(Cl + CF(3)CHClOCHF(2), isoflurane) = (4.5 ± 0.8) × 10(-15), k(Cl + CF(3)CHFOCHF(2), desflurane) = (1.0 ± 0.3) × 10(-15), k(Cl + (CF(3))(2)CHOCH(2)F, sevoflurane) = (1.1 ± 0.1) × 10(-13), and k(OH + (CF(3))(2)CHOCH(2)F) = (3.5 ± 0.7) × 10(-14) cm(3) molecule(-1) in 700 Torr of N(2)/air diluent at 295 ± 2 K. An upper limit of 6 × 10(-17) cm(3) molecule(-1) was established for k(Cl + (CF(3))(2)CHOC(O)F). The laser photolysis/laser-induced fluorescence (LP/LIF) technique was employed to determine hydroxyl radical rate coefficients as a function of temperature (241-298 K): k(OH + CF(3)CHFOCHF(2)) = (7.05 ± 1.80) × 10(-13) exp[-(1551 ± 72)/T] cm(3) molecule(-1); k(296 ± 1 K) = (3.73 ± 0.08) × 10(-15) cm(3) molecule(-1), and k(OH + (CF(3))(2)CHOCH(2)F) = (9.98 ± 3.24) × 10(-13) exp[-(969 ± 82)/T] cm(3) molecule(-1); k(298 ± 1 K) = (3.94 ± 0.30) × 10(-14) cm(3) molecule(-1). The rate coefficient of k(OH + CF(3)CHClOCHF(2), 296 ± 1 K) = (1.45 ± 0.16) × 10(-14) cm(3) molecule(-1) was also determined. Chlorine atoms react with CF(3)CHFOCHF(2) via H-abstraction to give CF(3)CFOCHF(2) and CF(3)CHFOCF(2) radicals in yields of approximately 83% and 17%. The major atmospheric fate of the CF(3)C(O)FOCHF(2) alkoxy radical is decomposition via elimination of CF(3) to give FC(O)OCHF(2) and is unaffected by the method used to generate the CF(3)C(O)FOCHF(2) radicals. CF(3)CHFOCF(2) radicals add O(2) and are converted by subsequent reactions into CF(3)CHFOCF(2)O alkoxy radicals, which decompose to give COF(2) and CF(3)CHFO radicals. In 700 Torr of air 82% of CF(3)CHFO radicals undergo C-C scission to yield HC(O)F and CF(3) radicals with the remaining 18% reacting with O(2) to give CF(3)C(O)F. Atmospheric oxidation of (CF(3))(2)CHOCH(2)F gives (CF(3))(2)CHOC(O)F in a molar yield of 93 ± 6% with CF(3)C(O)CF(3) and HCOF as minor products. The IR spectra of (CF(3))(2)CHOC(O)F and FC(O)OCHF(2) are reported for the first time. The atmospheric lifetimes of CF(3)CHClOCHF(2), CF(3)CHFOCHF(2), and (CF(3))(2)CHOCH(2)F (sevoflurane) are estimated at 3.2, 14, and 1.1 years, respectively. The 100 year time horizon global warming potentials of isoflurane, desflurane, and sevoflurane are 510, 2540, and 130, respectively. The atmospheric degradation products of these anesthetics are not of environmental concern.
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Affiliation(s)
- Mads P Sulbaek Andersen
- Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 183-901, Pasadena, California 91109, United States.
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Bravo I, Díaz-de-Mera Y, Aranda A, Moreno E, Nutt DR, Marston G. Radiative efficiencies for fluorinated esters: indirect global warming potentials of hydrofluoroethers. Phys Chem Chem Phys 2011; 13:17185-93. [DOI: 10.1039/c1cp21874c] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Sulbaek Andersen M, Sander S, Nielsen O, Wagner D, Sanford T, Wallington T. Inhalation anaesthetics and climate change † †This article is accompanied by the Editorial. Br J Anaesth 2010; 105:760-6. [DOI: 10.1093/bja/aeq259] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Zhang H, Liu CY, Zhang GL, Hou WJ, Sun M, Liu B, Li ZS. Theoretical studies of the reactions of Cl atoms with CF3CH2OCH n F(3−n) (n = 1, 2, 3). Theor Chem Acc 2010. [DOI: 10.1007/s00214-010-0746-2] [Citation(s) in RCA: 9] [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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Sulbaek Andersen MP, Hurley MD, Andersen VF, Nielsen OJ, Wallington TJ. CHF2OCHF2 (HFE-134): IR Spectrum and Kinetics and Products of the Chlorine-Atom-Initiated Oxidation. J Phys Chem A 2010; 114:4963-7. [DOI: 10.1021/jp101507f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Mads P. Sulbaek Andersen
- Department of Chemistry, 572 Rowland Hall, University of California Irvine, Irvine, California 92697-2025, System Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, Michigan 48121-2053, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Michael D. Hurley
- Department of Chemistry, 572 Rowland Hall, University of California Irvine, Irvine, California 92697-2025, System Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, Michigan 48121-2053, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Vibeke F. Andersen
- Department of Chemistry, 572 Rowland Hall, University of California Irvine, Irvine, California 92697-2025, System Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, Michigan 48121-2053, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Ole J. Nielsen
- Department of Chemistry, 572 Rowland Hall, University of California Irvine, Irvine, California 92697-2025, System Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, Michigan 48121-2053, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
| | - Timothy J. Wallington
- Department of Chemistry, 572 Rowland Hall, University of California Irvine, Irvine, California 92697-2025, System Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, Michigan 48121-2053, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark
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Young CJ, Mabury SA. Atmospheric perfluorinated acid precursors: chemistry, occurrence, and impacts. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2010; 208:1-109. [PMID: 20811862 DOI: 10.1007/978-1-4419-6880-7_1] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Perfluorocarboxylic acids (PFCAs) can be found from the hydrolysis of perfluoroacyl fluorides and chlorides, which can be produced in three separate ways in the atmosphere. Alternatively, PFCAs can be formed directly in the gas phase through reaction of perfluoroacyl peroxy radicals or perfluorinated aldehyde hydrates. All five mechanisms have been elucidated using smog chamber techniques. Yields of the PFCAs from this process vary from less than 10% to greater than 100%, depending on the mechanism. The formation of perfluorosulfonic acids in the atmosphere can also occur, though the mechanism has not been entirely elucidated. A large number of compounds have been confirmed as perfluorinated acid precursors, including CFC-replacement compounds, anesthetics, fluorotelomer compounds, and perfluorosulfonamides. Levels of some of these compounds have been measured in the atmosphere, but concentration for the majority have yet to be detected. It is clear that atmospheric oxidation of volatile precursors contributes to the overall burden of PFAs, though the extent to which this occurs is compound and environment dependent and is difficult to assess accurately.
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Affiliation(s)
- Cora J Young
- Department of Chemistry, University of Toronto, Toronto, ON, M5S 3H6, Canada.
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Yang L, Liu JY, Wan SQ, Li ZS. Theoretical studies of the reactions of CF3CHCLOCHF2/CF3CHFOCHF2 with OH radical and Cl atom and their product radicals with OH. J Comput Chem 2009; 30:565-80. [PMID: 18780357 DOI: 10.1002/jcc.21079] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The mechanisms and dynamics studies of the OH radical and Cl atom with CF(3)CHClOCHF(2) and CF(3)CHFOCHF(2) have been carried out theoretically. The geometries and frequencies of all the stationary points are optimized at the B3LYP/6-311G(d,p) level, and the energy profiles are further refined by interpolated single-point energies (ISPE) method at the G3(MP2) level of theory. For each reaction, two H-abstraction channels are found and four products (CF(3)CHFOCF(2), CF(3)CFOCHF(2), and CF(3)CHClOCF(2), CF(3)CClOCHF(2)) are produced during the above processes. The rate constants for the CF(3)CHClOCHF(2)/CF(3)CHFOCHF(2) + OH/Cl reactions are calculated by canonical variational transition-state theory (CVT) within 200-2000 K, and the small-curvature tunneling is included. The total rate constants calculated from the sum of the individual rate constants and the branching ratios are in good agreement with the experimental data. The Arrhenius expressions for the reactions are obtained. Our calculation shows that the substitution of Cl by F decreases the reactivity of CF(3)CHClOCHF(2) toward OH and Cl. In addition, the mechanisms of subsequent reactions of product radicals and OH radical are further investigated at the G3(MP2)//B3LYP/6-311G(d,p) level, and the main products are predicted in the this article.
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Affiliation(s)
- Lei Yang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China
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Wallington TJ, Hurley MD, Javadi MS, Nielsen OJ. Kinetics and products of chlorine atom initiated oxidation of HCF2OCF2OCF2CF2OCF2H and HCF2O(CF2O)n-(CF2CF2O)mCF2H. INT J CHEM KINET 2008. [DOI: 10.1002/kin.20349] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yang L, Liu JY, Wang L, He HQ, Wang Y, Li ZS. Theoretical study of the reactions CF3CH2OCHF2+ OH/Cl and its product radicals and parent ether(CH3CH2OCH3) with OH. J Comput Chem 2007; 29:550-61. [PMID: 17705163 DOI: 10.1002/jcc.20813] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A dual-level direct dynamic method is employed to study the reaction mechanisms of CF3CH2OCHF2 (HFE-245fa2; HFE-245mf) with the OH radicals and Cl atoms. Two hydrogen abstraction channels and two displacement processes are found for each reaction. For further study, the reaction mechanisms of its products (CF3CH2OCF2 and CF3CHOCHF2) and parent ether CH3CH2OCH3 with OH radical are investigated theoretically. The geometries and frequencies of all the stationary points and the minimum energy paths (MEPs) are calculated at the B3LYP/6-311G(d,p) level. The energetic information along the MEPs is further refined at the G3(MP2) level of theory. For reactions CF3CH2OCHF2 + OH/Cl, the calculation indicates that the hydrogen abstraction from --CH2-- group is the dominant reaction channel, and the displacement processes may be negligible because of the high barriers. The standard enthalpies of formation for the reactant CF3CH2OCHF2, and two products CF3CH2OCHF2 and CF3CHOCHF2 are evaluated via group-balanced isodesmic reactions. The rate constants of reactions CF3CH2OCHF2 + OH/Cl and CH3CH2OCH3 + OH are estimated by using the variational transition state theory over a wide range of temperature (200-2000 K). The agreement between the theoretical and experimental rate constants is good in the measured temperature range. From the comparison between the rate constants of the reactions CF3CH2OCHF2 and CH3CH2OCH3 with OH, it is shown that the fluorine substitution decreases the reactivity of the C--H bond.
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Affiliation(s)
- Lei Yang
- State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun 130023, People's Republic of China
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Dalmasso PR, Nieto JD, Taccone RA, Teruel MA, Lane SI. Rate constants for reaction of Cl atoms with hydrofluoroethers. J PHYS ORG CHEM 2007. [DOI: 10.1002/poc.1077] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Oyaro N, Sellevåg SR, Nielsen CJ. Atmospheric Chemistry of Hydrofluoroethers: Reaction of a Series of Hydrofluoroethers with OH Radicals and Cl Atoms, Atmospheric Lifetimes, and Global Warming Potentials. J Phys Chem A 2004; 109:337-46. [PMID: 16833352 DOI: 10.1021/jp047860c] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The kinetics of the OH radical and Cl atom reactions with nine fluorinated ethers have been studied by the relative rate method at 298 K and 1013 hPa using gas chromatography-mass spectroscopy (GC-MS) detection: k(OH + CH3CH2OCF3) = (1.55 +/- 0.25) x 10(-13), k(OH + CF3CH2OCH3) = (5.7 +/- 0.8) x 10(-13),k(OH + CF3CH2OCHF2) = (9.1 +/- 1.1) x 10(-15), k(OH + CF3CHFOCHF2) = (6.5 +/- 0.8) x 10(-15), k(OH + CHF2CHFOCF3) = (6.8 +/- 1.1) x 10(-15), k(OH + CF3CHFOCF3) < 1 x 10(-15), k(OH + CF3CHFCF2OCHF2) = (1.69 +/- 0.26) x 10(-14), k(OH + CF3CHFCF2OCH2CH3) = (1.47 +/- 0.13) x 10(-13), k(OH + CF3CF2CF2OCHFCF3) < 1 x 10(-15), k(Cl + CH3CH2OCF3) = (2.2 +/- 0.8) x 10(-12), k(Cl + CF3CH2OCH3) = (1.8 +/- 0.9) x 10(-11), k(Cl + CF3CH2OCHF2) = (1.5 +/- 0.4) x 10(-14), k(Cl + CF3CHFOCHF2) = (1.1 +/- 1.9) x 10(-15), k(Cl + CHF2CHFOCF3) = (1.2 +/- 2.0) x 10(-15), k(Cl + CF3CHFOCF3) < 3 x 10(-15), k(Cl + CF3CHFCF2OCHF2) < 6 x 10(-16), k(Cl + CF3CHFCF2OCH2CH3) = (3.1 +/- 1.1) x 10(-12), and k(Cl + CF3CF2CF2OCHFCF3) < 3 x 10(-15) cm3 molecule(-1) s(-1). The error limits include three standard deviations (3 sigma) from the statistical data analyses, as well as the errors in the rate coefficients of the reference compounds that are used. Infrared absorption cross sections and estimates of the trophospheric lifetimes and the global warming potentials of the fluorinated ethers are presented. The atmospheric degradation of the compounds is discussed.
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Affiliation(s)
- Nathan Oyaro
- Department of Chemistry, University of Oslo, P.O. Box 1033 Blindern, N-0315 Oslo, Norway
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23
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Papadimitriou VC, Kambanis KG, Lazarou YG, Papagiannakopoulos P. Kinetic Study for the Reactions of Several Hydrofluoroethers with Chlorine Atoms. J Phys Chem A 2004. [DOI: 10.1021/jp031081z] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | - Yannis G. Lazarou
- Department of Chemistry, University of Crete, Heraklion 71409, Crete, Greece
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Orlando JJ, Tyndall GS, Wallington TJ. The Atmospheric Chemistry of Alkoxy Radicals. Chem Rev 2003; 103:4657-90. [PMID: 14664628 DOI: 10.1021/cr020527p] [Citation(s) in RCA: 241] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John J Orlando
- Atmospheric Chemistry Division, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307-3000, USA.
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