1
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Salierno G. On the Chemical Pathways Influencing the Effective Global Warming Potential of Commercial Hydrofluoroolefin Gases. CHEMSUSCHEM 2024; 17:e202400280. [PMID: 38576083 DOI: 10.1002/cssc.202400280] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/28/2024] [Accepted: 04/03/2024] [Indexed: 04/06/2024]
Abstract
The enforcement of a global hydrofluorocarbon (HFC) refrigerant phase down led to the introduction of hydrofluoroolefins (HFOs) as a low Global Warming Potential (GWP) substitute, given their low atmospheric lifetime. However, to this date it is not fully clear the long-term atmospheric fate of HFOs primary degradation products: trifluoro acetaldehyde (TFE), trifluoro acetyl fluoride (TFF), and trifluoroacetic acid (TFA). It particularly concerns the possibility of forming HFC-23, a potent global warming agent. Although the atmospheric reaction networks of TFE, TFF, and TFA have a fair level of complexity, the relevant atmospheric chemical pathways are well characterized in the literature, enabling a comprehensive hazard assessment of HFC-23 formation as a secondary HFO breakdown product in diverse scenarios. A lower bound of the HFOs effective GWP in a baseline scenario is found above regulatory thresholds. While further research is crucial to refine climate risk assessments, the existing evidence suggests a non-negligible climate hazard associated with HFOs.
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Affiliation(s)
- Gabriel Salierno
- Toxics Use Reduction Institute, University of Massachusetts - Lowell, 126 John Street, Lowell, Massachusetts, United States of America
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2
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Wang Y, Liu L, Qiao X, Sun M, Guo J, Zhang J, Zhao B. Projections of National-Gridded Emissions of Hydrofluoroolefins (HFOs) in China. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:8650-8659. [PMID: 37235871 DOI: 10.1021/acs.est.2c09263] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Hydrofluoroolefins (HFOs) are being used as substitutes for potent greenhouse gas hydrofluorocarbons (HFCs). However, the use and environmental impacts of HFOs are of great concern due to the rapid degradation of HFOs to produce persistent and phytotoxic trifluoroacetic acid (TFA). Here, we provide a comprehensive projection of HFO emissions in China during 2024-2060 for the first time. Under the Kigali Amendment to the Montreal Protocol, China's HFO emissions are estimated to increase from 1.7 (1.3-2.3) to 148.8 (111.4-185.4) kt in 2024-2060 with cumulative emissions of 2.8 (2.0-3.5) Gt, and cumulative reduced HFCs emissions are evaluated to be 5.4 Gt CO2-equivalent. High HFO emissions would be distributed mainly in the North China Plain and the eastern and coastal areas. HFO-1234yf (2,3,3,3-tetrafluoropropene) contributes most of HFO emissions with a cumulative emission of 1.7 Gt in 2024-2060, while the cumulative increment of TFA deposition from HFO-1234yf emissions would reach 0.4-1.0 Gt. The long-term national-gridded HFO emission inventories can provide scientific support for evaluating the environmental risks of HFOs and developing HFC phase-out pathways for addressing climate change.
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Affiliation(s)
- Yifei Wang
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Lu Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing, Jiangsu 210023, China
| | - Xueqi Qiao
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Mei Sun
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Junyu Guo
- College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Jianbo Zhang
- State Key Joint Laboratory for Environmental Simulation and Pollution Control, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China
| | - Bu Zhao
- School for Environment and Sustainability and Michigan Institute for Computational Discovery and Engineering, University of Michigan, Ann Arbor, Michigan 48109, United States
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3
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Barnes PW, Robson TM, Neale PJ, Williamson CE, Zepp RG, Madronich S, Wilson SR, Andrady AL, Heikkilä AM, Bernhard GH, Bais AF, Neale RE, Bornman JF, Jansen MAK, Klekociuk AR, Martinez-Abaigar J, Robinson SA, Wang QW, Banaszak AT, Häder DP, Hylander S, Rose KC, Wängberg SÅ, Foereid B, Hou WC, Ossola R, Paul ND, Ukpebor JE, Andersen MPS, Longstreth J, Schikowski T, Solomon KR, Sulzberger B, Bruckman LS, Pandey KK, White CC, Zhu L, Zhu M, Aucamp PJ, Liley JB, McKenzie RL, Berwick M, Byrne SN, Hollestein LM, Lucas RM, Olsen CM, Rhodes LE, Yazar S, Young AR. Environmental effects of stratospheric ozone depletion, UV radiation, and interactions with climate change: UNEP Environmental Effects Assessment Panel, Update 2021. Photochem Photobiol Sci 2022; 21:275-301. [PMID: 35191005 PMCID: PMC8860140 DOI: 10.1007/s43630-022-00176-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2021] [Accepted: 01/14/2022] [Indexed: 12/07/2022]
Abstract
The Environmental Effects Assessment Panel of the Montreal Protocol under the United Nations Environment Programme evaluates effects on the environment and human health that arise from changes in the stratospheric ozone layer and concomitant variations in ultraviolet (UV) radiation at the Earth's surface. The current update is based on scientific advances that have accumulated since our last assessment (Photochem and Photobiol Sci 20(1):1-67, 2021). We also discuss how climate change affects stratospheric ozone depletion and ultraviolet radiation, and how stratospheric ozone depletion affects climate change. The resulting interlinking effects of stratospheric ozone depletion, UV radiation, and climate change are assessed in terms of air quality, carbon sinks, ecosystems, human health, and natural and synthetic materials. We further highlight potential impacts on the biosphere from extreme climate events that are occurring with increasing frequency as a consequence of climate change. These and other interactive effects are examined with respect to the benefits that the Montreal Protocol and its Amendments are providing to life on Earth by controlling the production of various substances that contribute to both stratospheric ozone depletion and climate change.
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Affiliation(s)
- P W Barnes
- Biological Sciences and Environment Program, Loyola University New Orleans, New Orleans, USA
| | - T M Robson
- Organismal and Evolutionary Biology (OEB), Viikki Plant Science Centre (ViPS), University of Helsinki, Helsinki, Finland
| | - P J Neale
- Smithsonian Environmental Research Center, Edgewater, USA
| | | | - R G Zepp
- ORD/CEMM, US Environmental Protection Agency, Athens, GA, USA
| | - S Madronich
- Atmospheric Chemistry Observations and Modeling Laboratory, National Center for Atmospheric Research, Boulder, USA
| | - S R Wilson
- School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
| | - A L Andrady
- Chemical and Biomolecular Engineering, North Carolina State University, Apex, USA
| | - A M Heikkilä
- Finnish Meteorological Institute, Helsinki, Finland
| | | | - A F Bais
- Laboratory of Atmospheric Physics, Department of Physics, Aristotle University, Thessaloniki, Greece
| | - R E Neale
- Population Health Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - J F Bornman
- Food Futures Institute, Murdoch University, Perth, Australia.
| | | | - A R Klekociuk
- Antarctic Climate Program, Australian Antarctic Division, Kingston, Australia
| | - J Martinez-Abaigar
- Faculty of Science and Technology, University of La Rioja, La Rioja, Logroño, Spain
| | - S A Robinson
- Securing Antarctica's Environmental Future, Global Challenges Program and School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
| | - Q-W Wang
- Institute of Applied Ecology, Chinese Academy of Sciences (CAS), Shenyang, China
| | - A T Banaszak
- Unidad Académica De Sistemas Arrecifales, Universidad Nacional Autónoma De México, Puerto Morelos, Mexico
| | - D-P Häder
- Department of Biology, Friedrich-Alexander University, Möhrendorf, Germany
| | - S Hylander
- Centre for Ecology and Evolution in Microbial Model Systems-EEMiS, Linnaeus University, Kalmar, Sweden.
| | - K C Rose
- Biological Sciences, Rensselaer Polytechnic Institute, Troy, USA
| | - S-Å Wängberg
- Marine Sciences, University of Gothenburg, Gothenburg, Sweden
| | - B Foereid
- Environment and Natural Resources, Norwegian Institute of Bioeconomy Research, Ås, Norway
| | - W-C Hou
- Environmental Engineering, National Cheng Kung University, Tainan, Taiwan
| | - R Ossola
- Environmental System Science (D-USYS), ETH Zürich, Zürich, Switzerland
| | - N D Paul
- Lancaster Environment Centre, Lancaster University, Lancaster, UK
| | - J E Ukpebor
- Chemistry Department, Faculty of Physical Sciences, University of Benin, Benin City, Nigeria
| | - M P S Andersen
- Department of Chemistry and Biochemistry, California State University, Northridge, USA
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - J Longstreth
- The Institute for Global Risk Research, LLC, Bethesda, USA
| | - T Schikowski
- Research Group of Environmental Epidemiology, Leibniz Institute of Environmental Medicine, Düsseldorf, Germany
| | - K R Solomon
- Centre for Toxicology, School of Environmental Sciences, University of Guelph, Guelph, Canada
| | - B Sulzberger
- Academic Guest, Swiss Federal Institute of Aquatic Science and Technology, 8600, Dübendorf, Switzerland
| | - L S Bruckman
- Materials Science and Engineering, Case Western Reserve University, Cleveland, USA
| | - K K Pandey
- Wood Processing Division, Institute of Wood Science and Technology, Bangalore, India
| | - C C White
- Polymer Science and Materials Chemistry (PSMC), Exponent, Bethesda, USA
| | - L Zhu
- College of Materials Science and Engineering, Donghua University, Shanghai, China
| | - M Zhu
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University, Shanghai, China
| | - P J Aucamp
- Ptersa Environmental Consultants, Pretoria, South Africa
| | - J B Liley
- National Institute of Water and Atmospheric Research, Alexandra, New Zealand
| | - R L McKenzie
- National Institute of Water and Atmospheric Research, Alexandra, New Zealand
| | - M Berwick
- Internal Medicine, University of New Mexico, Albuquerque, USA
| | - S N Byrne
- Applied Medical Science, University of Sydney, Sydney, Australia
| | - L M Hollestein
- Department of Dermatology, Erasmus MC Cancer Institute, Rotterdam, The Netherlands
| | - R M Lucas
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - C M Olsen
- Population Health Department, QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - L E Rhodes
- Photobiology Unit, Dermatology Research Centre, School of Biological Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester, UK
| | - S Yazar
- Garvan Institute of Medical Research, Sydney, Australia
| | - A R Young
- St John's Institute of Dermatology, King's College London (KCL), London, UK
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4
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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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5
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Wu Z, Ji Y, Li H, Bi F, Yanqin R, Gao R, Liu C, Li L, Zhang H, Zhang X, Wang X. Study on the pyrolysis characteristics of a series of fluorinated cyclopentenes and implication of their environmental influence. Chem Phys Lett 2021. [DOI: 10.1016/j.cplett.2020.138213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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6
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Wennberg PO, Bates KH, Crounse JD, Dodson LG, McVay RC, Mertens LA, Nguyen TB, Praske E, Schwantes RH, Smarte MD, St Clair JM, Teng AP, Zhang X, Seinfeld JH. Gas-Phase Reactions of Isoprene and Its Major Oxidation Products. Chem Rev 2018. [PMID: 29522327 DOI: 10.1021/acs.chemrev.7b00439] [Citation(s) in RCA: 145] [Impact Index Per Article: 24.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Isoprene carries approximately half of the flux of non-methane volatile organic carbon emitted to the atmosphere by the biosphere. Accurate representation of its oxidation rate and products is essential for quantifying its influence on the abundance of the hydroxyl radical (OH), nitrogen oxide free radicals (NO x), ozone (O3), and, via the formation of highly oxygenated compounds, aerosol. We present a review of recent laboratory and theoretical studies of the oxidation pathways of isoprene initiated by addition of OH, O3, the nitrate radical (NO3), and the chlorine atom. From this review, a recommendation for a nearly complete gas-phase oxidation mechanism of isoprene and its major products is developed. The mechanism is compiled with the aims of providing an accurate representation of the flow of carbon while allowing quantification of the impact of isoprene emissions on HO x and NO x free radical concentrations and of the yields of products known to be involved in condensed-phase processes. Finally, a simplified (reduced) mechanism is developed for use in chemical transport models that retains the essential chemistry required to accurately simulate isoprene oxidation under conditions where it occurs in the atmosphere-above forested regions remote from large NO x emissions.
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7
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Wong TY. Smog induces oxidative stress and microbiota disruption. J Food Drug Anal 2017; 25:235-244. [PMID: 28911664 PMCID: PMC9332540 DOI: 10.1016/j.jfda.2017.02.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 02/22/2017] [Indexed: 02/04/2023] Open
Abstract
Smog is created through the interactions between pollutants in the air, fog, and sunlight. Air pollutants, such as carbon monoxide, heavy metals, nitrogen oxides, ozone, sulfur dioxide, volatile organic vapors, and particulate matters, can induce oxidative stress in human directly or indirectly through the formation of reactive oxygen species. The outermost boundary of human skin and mucous layers are covered by a complex network of human-associated microbes. The relation between these microbial communities and their human host are mostly mutualistic. These microbes not only provide nutrients, vitamins, and protection against other pathogens, they also influence human's physical, immunological, nutritional, and mental developments. Elements in smog can induce oxidative stress to these microbes, leading to community collapse. Disruption of these mutualistic microbiota may introduce unexpected health risks, especially among the newborns and young children. Besides reducing the burning of fossil fuels as the ultimate solution of smog formation, advanced methods by using various physical, chemical, and biological means to reduce sulfur and nitrogen contains in fossil fuels could lower smog formation. Additionally, information on microbiota disruption, based on functional genomics, culturomics, and general ecological principles, should be included in the risk assessment of prolonged smog exposure to the health of human populations.
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Affiliation(s)
- Tit-Yee Wong
- Department of Biological Sciences, University of Memphis, Memphis, TN 38120,
USA
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8
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Schwantes RH, Teng AP, Nguyen TB, Coggon MM, Crounse JD, St Clair JM, Zhang X, Schilling KA, Seinfeld JH, Wennberg PO. Isoprene NO3 Oxidation Products from the RO2 + HO2 Pathway. J Phys Chem A 2015; 119:10158-71. [PMID: 26335780 DOI: 10.1021/acs.jpca.5b06355] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the products of the reaction of the hydroperoxy radical (HO(2)) with the alkylperoxy radical formed following addition of the nitrate radical (NO(3)) and O(2) to isoprene. NO(3) adds preferentially to the C(1) position of isoprene (>6 times more favorably than addition to C(4)), followed by the addition of O(2) to produce a suite of nitrooxy alkylperoxy radicals (RO(2)). At an RO(2) lifetime of ∼30 s, δ-nitrooxy and β-nitrooxy alkylperoxy radicals are present in similar amounts. Gas-phase product yields from the RO(2) + HO(2) pathway are identified as 0.75-0.78 isoprene nitrooxy hydroperoxide (INP), 0.22 methyl vinyl ketone (MVK) + formaldehyde (CH(2)O) + hydroxyl radical (OH) + nitrogen dioxide (NO(2)), and 0-0.03 methacrolein (MACR) + CH(2)O + OH + NO(2). We further examined the photochemistry of INP and identified propanone nitrate (PROPNN) and isoprene nitrooxy hydroxyepoxide (INHE) as the main products. INHE undergoes similar heterogeneous chemistry as isoprene dihydroxy epoxide (IEPOX), likely contributing to atmospheric secondary organic aerosol formation.
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Affiliation(s)
- Rebecca H Schwantes
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Alexander P Teng
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Tran B Nguyen
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Matthew M Coggon
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - John D Crounse
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Jason M St Clair
- Atmospheric Chemistry and Dynamics Laboratory, NASA Goddard Space Flight Center , Greenbelt, Maryland 20771, United States.,Joint Center for Earth Systems Technology, University of Maryland Baltimore County , Baltimore, Maryland 21250, United States
| | - Xuan Zhang
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Katherine A Schilling
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - John H Seinfeld
- Division of Chemistry and Chemical Engineering, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States.,Division of Engineering and Applied Science, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
| | - Paul O Wennberg
- Division of Geological and Planetary Sciences, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States.,Division of Engineering and Applied Science, California Institute of Technology , 1200 East California Boulevard, Pasadena, California 91125, United States
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9
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Wallington TJ, Sulbaek Andersen MP, Nielsen OJ. Atmospheric chemistry of short-chain haloolefins: photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs). CHEMOSPHERE 2015; 129:135-141. [PMID: 25070769 DOI: 10.1016/j.chemosphere.2014.06.092] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2014] [Revised: 06/26/2014] [Accepted: 06/27/2014] [Indexed: 06/03/2023]
Abstract
Short-chain haloolefins are being introduced as replacements for saturated halocarbons. The unifying chemical feature of haloolefins is the presence of a CC double bond which causes the atmospheric lifetimes to be significantly shorter than for the analogous saturated compounds. We discuss the atmospheric lifetimes, photochemical ozone creation potentials (POCPs), global warming potentials (GWPs), and ozone depletion potentials (ODPs) of haloolefins. The commercially relevant short-chain haloolefins CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) have short atmospheric lifetimes (days to weeks), negligible POCPs, negligible GWPs, and ODPs which do not differ materially from zero. In the concentrations expected in the environment their atmospheric degradation products will have a negligible impact on ecosystems. CF3CFCH2 (1234yf), trans-CF3CHCHF (1234ze(Z)), CF3CFCF2 (1216), cis-CF3CHCHCl (1233zd(Z)), and trans-CF3CHCHCl (1233zd(E)) are environmentally acceptable.
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Affiliation(s)
- T J Wallington
- System Analytics and Environmental Sciences Department, Ford Motor Company, Mail Drop RIC-2122, Dearborn, MI 48121-2053, USA.
| | - M P Sulbaek Andersen
- Department of Chemistry and Biochemistry, California State University Northridge, 18111 Nordhoff St., Northridge, CA 91330-8262, USA
| | - O J Nielsen
- Copenhagen Center for Atmospheric Research, Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark
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10
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Wang Z, Cousins IT, Scheringer M, Buck RC, Hungerbühler K. Global emission inventories for C4-C14 perfluoroalkyl carboxylic acid (PFCA) homologues from 1951 to 2030, part II: the remaining pieces of the puzzle. ENVIRONMENT INTERNATIONAL 2014; 69:166-76. [PMID: 24861268 DOI: 10.1016/j.envint.2014.04.006] [Citation(s) in RCA: 148] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 04/10/2014] [Accepted: 04/11/2014] [Indexed: 05/17/2023]
Abstract
We identify eleven emission sources of perfluoroalkyl carboxylic acids (PFCAs) that have not been discussed in the past. These sources can be divided into three groups: [i] PFCAs released as ingredients or impurities, e.g., historical and current use of perfluorobutanoic acid (PFBA), perfluorohexanoic acid (PFHxA) and their derivatives; [ii] PFCAs formed as degradation products, e.g., atmospheric degradation of some hydrofluorocarbons (HFCs) and hydrofluoroethers (HFEs); and [iii] sources from which PFCAs are released as both impurities and degradation products, e.g., historical and current use of perfluorobutane sulfonyl fluoride (PBSF)- and perfluorohexane sulfonyl fluoride (PHxSF)-based products. Available information confirms that these sources were active in the past or are still active today, but due to a lack of information, it is not yet possible to quantify emissions from these sources. However, our review of the available information on these sources shows that some of the sources may have been significant in the past (e.g., the historical use of PFBA-, PFHxA-, PBSF- and PHxSF-based products), whereas others can be significant in the long-term (e.g., (bio)degradation of various side-chain fluorinated polymers where PFCA precursors are chemically bound to the backbone). In addition, we summarize critical knowledge and data gaps regarding these sources as a basis for future research.
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Affiliation(s)
- Zhanyun Wang
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
| | - Ian T Cousins
- Department of Applied Environmental Science (ITM), Stockholm University, SE-10691 Stockholm, Sweden
| | - Martin Scheringer
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland.
| | - Robert C Buck
- E.I. du Pont de Nemours & Co. Inc., DuPont Chemicals and Fluoroproducts, 974 Centre Road, CRP 702-2211B, Wilmington, DE 19880-0702, USA
| | - Konrad Hungerbühler
- Institute for Chemical and Bioengineering, ETH Zurich, Wolfgang-Pauli-Strasse 10, CH-8093 Zürich, Switzerland
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11
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Shao Y, Hou H, Wang B. Theoretical study of the mechanisms and kinetics of the reactions of hydroperoxy (HO2) radicals with hydroxymethylperoxy (HOCH2O2) and methoxymethylperoxy (CH3OCH2O2) radicals. Phys Chem Chem Phys 2014; 16:22805-14. [PMID: 25243915 DOI: 10.1039/c4cp02747g] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The peroxy–peroxy radical reactions show spin, conformation and temperature dependence, forming formic acid and hydroxyl radicals.
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Affiliation(s)
- Youxiang Shao
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan, People's Republic of China
| | - Hua Hou
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan, People's Republic of China
| | - Baoshan Wang
- College of Chemistry and Molecular Sciences
- Wuhan University
- Wuhan, People's Republic of China
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12
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Antiñolo M, Jiménez E, González S, Albaladejo J. Atmospheric Chemistry of CF3CF2CHO: Absorption Cross Sections in the UV and IR Regions, Photolysis at 308 nm, and Gas-Phase Reaction with OH Radicals (T = 263–358 K). J Phys Chem A 2013; 118:178-86. [DOI: 10.1021/jp410283v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- María Antiñolo
- Departamento
de Química Física, Facultad de Ciencias y Tecnologías
Químicas, Universidad de Castilla-La Mancha, Avda. Camilo
José Cela s/n, 13071 Ciudad Real, Spain
| | - Elena Jiménez
- Departamento
de Química Física, Facultad de Ciencias y Tecnologías
Químicas, Universidad de Castilla-La Mancha, Avda. Camilo
José Cela s/n, 13071 Ciudad Real, Spain
- Instituto
de Investigación en Combustión y Contaminación
Atmosférica, Universidad de Castilla-La Mancha, Camino de Moledores
s/n, Edificio Polivalente, 13071 Ciudad Real, Spain
| | - Sergio González
- Departamento
de Química Física, Facultad de Ciencias y Tecnologías
Químicas, Universidad de Castilla-La Mancha, Avda. Camilo
José Cela s/n, 13071 Ciudad Real, Spain
| | - José Albaladejo
- Departamento
de Química Física, Facultad de Ciencias y Tecnologías
Químicas, Universidad de Castilla-La Mancha, Avda. Camilo
José Cela s/n, 13071 Ciudad Real, Spain
- Instituto
de Investigación en Combustión y Contaminación
Atmosférica, Universidad de Castilla-La Mancha, Camino de Moledores
s/n, Edificio Polivalente, 13071 Ciudad Real, Spain
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13
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Jackson DA, Wallington TJ, Mabury SA. Atmospheric oxidation of polyfluorinated amides: historical source of perfluorinated carboxylic acids to the environment. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:4317-4324. [PMID: 23586598 DOI: 10.1021/es400617v] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Polyfluorinated amides (PFAMs) are a class of fluorinated compounds which were produced as unintentional byproducts in the electrochemical fluorination process used for polyfluorinated sulfonamide synthesis in 1947-2002. To investigate the historical potential of PFAMs as an atmospheric perfluorinated acid (PFCA) source we studied N-ethylperfluorobutyramide (EtFBA) as a surrogate for longer chained PFAMs. Smog chamber relative rate techniques were used to measure bimolecular rate coefficients for reactions of EtFBA with chlorine atoms and hydroxyl radicals. It was found kCl = (2.08 ± 0.15) × 10(-11) cm(3) molecule(-1) s(-1) and kOH = (2.65 ± 0.50) × 10(-12) cm(3) molecule(-1) s(-1) and the atmospheric lifetime of EtFBA with respect to reaction with OH was estimated to be approximately 4.4 days. Offline sampling with both GC-MS and LC-MS/MS techniques was used to determine the products and hence a plausible pathway of atmospheric oxidation of EtFBA. Three primary oxidation products were observed by GC-MS, the N-dealkylation product C3F7C(O)NH2 and two carbonyl products, probably C3F7C(O)N(H)C(O)CH3 and C3F7C(O)N(H)CH2CHO. These primary products react further to give perfluorocarboxylic acids (PFCAs) as detected by LC-MS/MS, suggesting that eight carbon PFAMs were a historical source of PFCAs to remote regions, including the Canadian Arctic.
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Affiliation(s)
- Derek A Jackson
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON, Canada M5S 3H6
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14
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Andersen MPS, Nielsen OJ, Hurley MD, Wallington TJ. Atmospheric chemistry of t-CF3CHCHCl: products and mechanisms of the gas-phase reactions with chlorine atoms and hydroxyl radicals. Phys Chem Chem Phys 2012; 14:1735-48. [DOI: 10.1039/c1cp22925g] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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15
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Orlando JJ, Tyndall GS. Laboratory studies of organic peroxy radical chemistry: an overview with emphasis on recent issues of atmospheric significance. Chem Soc Rev 2012; 41:6294-317. [PMID: 22847633 DOI: 10.1039/c2cs35166h] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Affiliation(s)
- John J Orlando
- National Center for Atmospheric Research, Earth System Laboratory, Atmospheric Chemistry Division, Boulder, USA.
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16
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Jackson DA, Young CJ, Hurley MD, Wallington TJ, Mabury SA. Atmospheric degradation of perfluoro-2-methyl-3-pentanone: photolysis, hydrolysis and hydration. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2011; 45:8030-8036. [PMID: 21466195 DOI: 10.1021/es104362g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Perfluorinated carboxylic acids are widely distributed in the environment, including remote regions, but their sources are not well understood. Perfluoropropionic acid (PFPrA, CF(3)CF(2)C(O)OH) has been observed in rainwater but the observed amounts can not be explained by currently known degradation pathways. Smog chamber studies were performed to assess the potential of photolysis of perfluoro-2-methyl-3-pentanone (PFMP, CF(3)CF(2)C(O)CF(CF(3))(2)), a commonly used fire-fighting fluid, to contribute to the observed PFPrA loadings. The photolysis of PFMP gives CF(3)CF(2)C·(O) and ·CF(CF(3))(2) radicals. A small (0.6%) but discernible yield of PFPrA was observed in smog chamber experiments by liquid chromatography-mass spectrometry offline chamber samples. The Tropospheric Ultraviolet-Visible (TUV) model was used to estimate an atmospheric lifetime of PFMP with respect to photolysis of 4-14 days depending on latitude and time of year. PFMP can undergo hydrolysis to produce PFPrA and CF(3)CFHCF(3) (HFC-227ea) in a manner analogous to the Haloform reaction. The rate of hydrolysis was measured using (19)F NMR at two different pHs and was too slow to be of importance in the atmosphere. Hydration of PFMP to give a geminal diol was investigated computationally using density functional theory. It was determined that hydration is not an important environmental fate of PFMP. The atmospheric fate of PFMP seems to be direct photolysis which, under low NO(x) conditions, gives PFPrA in a small yield. PFMP degradation contributes to, but does not appear to be the major source of, PFPrA observed in rainwater.
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Affiliation(s)
- Derek A Jackson
- Department of Chemistry, University of Toronto , 80 St. George Street, Toronto, ON, Canada M5S 3H6
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17
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Chiappero MS, Argüello GA, Hurley MD, Wallington TJ. Atmospheric chemistry of n-C6F13CH2CHO: formation from n-C6F13CH2CH2OH, kinetics, and mechanisms of reactions with chlorine atoms and OH radicals. J Phys Chem A 2010; 114:6131-7. [PMID: 20433179 DOI: 10.1021/jp101587m] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Smog chamber FTIR techniques were used to measure k(Cl + n-C(6)F(13)CH(2)CHO) = (1.84 +/- 0.22) x 10(-11), k(Cl + n-C(6)F(13)CHO) = (1.75 +/- 0.70) x 10(-12), and k(OH + n-C(6)F(13)CH(2)CHO) = (2.15 +/- 0.26) x 10(-12) cm(3) molecule(-1) s(-1) in 700 Torr of N(2) or air diluent at 296 +/- 2K. The chlorine-atom-initiated oxidation of n-C(6)F(13)CH(2)CH(2)OH in air gives n-C(6)F(13)CH(2)CHO in a molar yield of 99 +/- 8%. The atmospheric fate of n-C(6)F(13)CH(2)C(O) radicals is reaction with O(2), while the fate of n-C(6)F(13)C(O) radicals is decomposition to give n-C(6)F(13) radicals and CO. The results are discussed with respect to the atmospheric chemistry of fluorinated alcohols and the formation of perfluorocarboxylic acids.
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Affiliation(s)
- Malisa S Chiappero
- INFIQC, Departamento de Físico Química, Facultad de Ciencias Químicas, Universidad Nacional de Córdoba, Ciudad Universitaria, 5000 Córdoba, Argentina
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18
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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: 30] [Impact Index Per Article: 2.1] [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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19
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Benskin JP, Holt A, Martin JW. Isomer-specific biotransformation rates of a perfluorooctane sulfonate (PFOS)-precursor by cytochrome P450 isozymes and human liver microsomes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:8566-72. [PMID: 20028053 DOI: 10.1021/es901915f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The exposure sources of perfluorooctane sulfonate (PFOS) in humans and wildlife are not well characterized. Human biomonitoring data show that PFOS profiles may consist of up to approximately 50% branched isomers, despite the fact that historical direct manufacturing of PFOS generally resulted in products containing no more than approximately 30% branched isomers. These observations cannot be explained based on what is known about the pharmacokinetics of branched PFOS isomers; thus, here we examined the relative isomer-specific biotransformation rates of a model PFOS-precursor (N-ethylperfluorooctane sulfonamide, NEtFOSA) with human microsomes and recombinant human cytochrome P450s (CYPs) 2C9 and 2C19. Using solid phase microextraction-gas chromatography-electron capture detection to monitor NEtFOSA disappearance, and liquid chromatography-tandem mass spectrometry to monitor product formation, we showed that, in general, human microsomes and CYP isozymes transformed the branched isomers more rapidly than linear NEtFOSA. Among branched isomers, perfluoroalkyl branching geometry significantly influenced the rate of biotransformation. As a result, PFOS isomer patterns in biota exposed predominantly to precursors could be much different than expected from the isomer pattern of the precursor. While these data are suggestive that the relatively high abundance of branched PFOS isomers present in some humans, or wildlife, may be explained by substantial exposure to PFOS-precursors, in vivo studies with other relevant PFOS-precursors are warranted to validate this as a biomarker of exposure source.
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Affiliation(s)
- Jonathan P Benskin
- Division of Analytical and Environmental Toxicology, Department of Laboratory Medicine, University of Alberta, Canada
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20
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Rayne S, Forest K, Friesen KJ. Estimated congener specific gas-phase atmospheric behavior and fractionation of perfluoroalkyl compounds: rates of reaction with atmospheric oxidants, air-water partitioning, and wet/dry deposition lifetimes. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2009; 44:936-954. [PMID: 19827486 DOI: 10.1080/10934520902996815] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A quantitative structure-activity model has been validated for estimating congener specific gas-phase hydroxyl radical reaction rates for perfluoroalkyl sulfonic acids (PFSAs), carboxylic acids (PFCAs), aldehydes (PFAls) and dihydrates, fluorotelomer olefins (FTOls), alcohols (FTOHs), aldehydes (FTAls), and acids (FTAcs), and sulfonamides (SAs), sulfonamidoethanols (SEs), and sulfonamido carboxylic acids (SAAs), and their alkylated derivatives based on calculated semi-empirical PM6 method ionization potentials. Corresponding gas-phase reaction rates with nitrate radicals and ozone have also been estimated using the computationally derived ionization potentials. Henry's law constants for these classes of perfluorinated compounds also appear to be reasonably approximated by the SPARC software program, thereby allowing estimation of wet and dry atmospheric deposition rates. Both congener specific gas-phase atmospheric and air-water interface fractionation of these compounds is expected, complicating current source apportionment perspectives and necessitating integration of such differential partitioning influences into future multimedia models. The findings will allow development and refinement of more accurate and detailed local through global scale atmospheric models for the atmospheric fate of perfluoroalkyl compounds.
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Affiliation(s)
- Sierra Rayne
- Department of Chemistry, University of Winnipeg, Winnipeg, Manitoba, Canada.
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21
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Singh S, Hernandez S, Ibarra Y, Hasson AS. Kinetics and mechanism of the reactions ofn-butanal andn-pentanal with chlorine atoms. INT J CHEM KINET 2009. [DOI: 10.1002/kin.20383] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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22
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Cl-Initiated oxidation of N-ethyl-perfluoroalkanesulfonamides: A theoretical insight into the experimentally observed products. ACTA ACUST UNITED AC 2008. [DOI: 10.1016/j.theochem.2008.02.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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23
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Wallington TJ, Mabury SA, Hurley MD, Sulbaek Andersen MP, Nielsen OJ, Ellis DA, Martin JW. Comment on “Atmospheric Chemistry of Linear Perfluorinated Aldehydes: Dissociation Kinetics of CnF2n+1CO Radicals”. J Phys Chem A 2008; 112:576-7; discussion 577-8. [DOI: 10.1021/jp074587g] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- T. J. Wallington
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
| | - S. A. Mabury
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
| | - M. D. Hurley
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
| | - M. P. Sulbaek Andersen
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
| | - O. J. Nielsen
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
| | - D. A. Ellis
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
| | - J. W. Martin
- Ford Motor Company, RIC 2122, Dearborn, Michigan, 48121−2053, Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada, Department of Chemistry, University of California, 572 Rowland Hall, Irvine, California 92697-2025, Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark, Department of Chemistry, Trent University, 1600 West Bank Drive, Peterborough, Ontario K9J 7B8, Canada, and Division of Analytical and
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Waterland RL, Dobbs KD. Reply to “Comment on ‘Atmospheric Chemistry of Linear Perfluorinated Aldehydes: Dissociation Kinetics of C nF 2n+1CO Radicals'”. J Phys Chem A 2008. [DOI: 10.1021/jp075291d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert L. Waterland
- DuPont Central Research & Development, Experimental Station, P. O. Box 80320, Wilmington, Delaware 19880-0320
| | - Kerwin D. Dobbs
- DuPont Central Research & Development, Experimental Station, P. O. Box 80320, Wilmington, Delaware 19880-0320
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25
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Waterland RL, Dobbs KD. Atmospheric Chemistry of Linear Perfluorinated Aldehydes: Dissociation Kinetics of CnF2n+1CO Radicals. J Phys Chem A 2007; 111:2555-62. [PMID: 17388359 DOI: 10.1021/jp067587+] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Linear perfluorinated aldehydes (PFALs, CnF2n+1CHO) are important intermediate species in the atmospheric oxidation pathway of many polyfluorinated compounds. PFALs can be further oxidized in the gas phase to give perfluorinated carboxylic acids (PFCAs, CnF2n+1C(O)OH, n = 6, 12) which have been detected in animal tissues and at low parts per billion levels in human blood sera. In this paper, we report ab initio quantum chemistry calculations of the decarbonylation kinetics of CnF2n+1CO radicals. Our results show that CnF2n+1CO radicals have a strong tendency to decompose to give CnF2n+1 and CO under atmospheric conditions: the Arrhenius activation energies for decarbonylation of CF3CO, C2F5CO, and C3F7CO obtained using PMP4/6-311++G(2d,p) are 8.8, 6.6, and 5.8 kcal/mol, respectively, each of which is about 5 kcal/mol lower than the barrier for the corresponding nonfluorinated radicals. The lowering of the barrier for decarbonylation of CnF2n+1CO relative to that of CnH2n+1CO is well explained by electron withdrawal by F atoms that serve to weaken the critical C-CO bond. These results have important implications for the atmospheric fate of PFALs and the atmospheric pathways to PFCAs. The main effect of decarbonylation of CnF2n+1CO is to decrease the molar yield of CnF2n+1C(O)OH; if 100% of the CnF2n+1CO decompose, the yield of CnF2n+1C(O)OH must be zero. There is considerable scope for additional experimental and theoretical studies.
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Affiliation(s)
- Robert L Waterland
- DuPont Central Research & Development, Experimental Station, P. O. Box 80320, Wilmington, Delaware 19880-0320, USA.
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