Hydrofluorocarbons (HFCs) are man-made organic compounds that contain fluorine and hydrogen atoms, and are the most common type of organofluorine compounds. Most are gases at room temperature and pressure. They are frequently used in air conditioning and as refrigerants; R-134a (1,1,1,2-tetrafluoroethane) is one of the most commonly used HFCrefrigerants. In order to aid the recovery of the stratospheric ozone layer, HFCs were adopted to replace the more potent chlorofluorocarbons (CFCs), which were phased out from use by the Montreal Protocol, and hydrochlorofluorocarbons (HCFCs) which are presently being phased out.[1] HFCs replaced older chlorofluorocarbons such as R-12 and hydrochlorofluorocarbons such as R-21.[2] HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection.
They may not harm the ozone layer as much as the compounds they replace, but they still contribute to global warming --- with some like trifluoromethane having 11,700 times the warming potential of carbon dioxide.[3] Their atmospheric concentrations and contribution to anthropogenicgreenhouse gas emissions are rapidly increasing[quantify], causing international concern about their radiative forcing.
Fluorocarbons with few C–Fbonds behave similarly to the parent hydrocarbons, but their reactivity can be altered significantly. For example, both uracil and 5-fluorouracil are colourless, high-melting crystalline solids, but the latter is a potent anti-cancer drug. The use of the C-F bond in pharmaceuticals is predicated on this altered reactivity.[4] Several drugs and agrochemicals contain only one fluorine center or one trifluoromethyl group.
Environmental regulationedit
Unlike other greenhouse gases in the Paris Agreement, hydrofluorocarbons are included in other international negotiations.[5]
COVID-19 relief legislation, which included a measure that would require chemical manufacturers to phase down the production and use of HFCs, was passed by the United States House of Representatives and United States Senate on December 21, 2020.[11] The U.S. Environmental Protection Agency signed a final rule phasing down HFCs on 23 September, 2021.[12]
^Zaelke, Durwood; Borgford-Parnell, Nathan; Andersen., Stephen (11 January 2018). "Primer on HFCs" (PDF). Kristin Campbell, Xiaopu Sun, Dennis Clare,Claire Phillips, Stela Herschmann, Yuzhe PengLing, Alex Milgroom, Nancy J. Sherman. Institute for Governance & Sustainable Development (IGSD): 5. {{cite journal}}: Cite journal requires |journal= (help)
^ Milman, Oliver (22 September 2016). "100 countries push to phase out potentially disastrous greenhouse gas". The Guardian. London, UK. Retrieved 22 September 2016.
^Han, Wenfeng; Li, Ying; Tang, Haodong; Liu, Huazhang (2012). "Treatment of the potent greenhouse gas, CHF3—An overview". Journal of Fluorine Chemistry. 140: 7–16. doi:10.1016/j.jfluchem.2012.04.012.
^G. Siegemund, W. Schwertfeger, A. Feiring, B. Smart, F. Behr, H. Vogel, B. McKusick "Fluorine Compounds, Organic" in "Ullmann's Encyclopedia of Industrial Chemistry" 2005, Wiley-VCH, Weinheim. doi:10.1002/14356007.a11_349
^Davenport, Carol (23 July 2016). "A Sequel to the Paris Climate Accord Takes Shape in Vienna". New York Times. Retrieved 17 August 2016.
^ "The New York Declaration of the Coalition to Secure an Ambitious HFC Amendment". Washington, DC: US Department of State. 22 September 2016. Retrieved 22 September 2016.
^Johnston, Chris; Milman, Oliver; Vidal, John (15 October 2016). "Climate change: global deal reached to limit use of hydrofluorocarbons". The Guardian. Retrieved 15 October 2016.
^"Climate change: 'Monumental' deal to cut HFCs, fastest growing greenhouse gases". BBC News. 15 October 2016. Retrieved 15 October 2016.
^"Nations, Fighting Powerful Refrigerant That Warms Planet, Reach Landmark Deal". New York Times. 15 October 2016. Retrieved 15 October 2016.
^Baker Administration Planning Rule To Ban Hydrofluorocarbons
^Davenport, Coral (2020-12-22). "Congress included climate change legislation in its coronavirus relief deal". The New York Times. ISSN 0362-4331. Retrieved 2020-12-22.
hydrofluorocarbon, hfcs, made, organic, compounds, that, contain, fluorine, hydrogen, atoms, most, common, type, organofluorine, compounds, most, gases, room, temperature, pressure, they, frequently, used, conditioning, refrigerants, 134a, tetrafluoroethane, m. Hydrofluorocarbons HFCs are man made organic compounds that contain fluorine and hydrogen atoms and are the most common type of organofluorine compounds Most are gases at room temperature and pressure They are frequently used in air conditioning and as refrigerants R 134a 1 1 1 2 tetrafluoroethane is one of the most commonly used HFC refrigerants In order to aid the recovery of the stratospheric ozone layer HFCs were adopted to replace the more potent chlorofluorocarbons CFCs which were phased out from use by the Montreal Protocol and hydrochlorofluorocarbons HCFCs which are presently being phased out 1 HFCs replaced older chlorofluorocarbons such as R 12 and hydrochlorofluorocarbons such as R 21 2 HFCs are also used in insulating foams aerosol propellants as solvents and for fire protection Fluoromethane a hydrofluorocarbon They may not harm the ozone layer as much as the compounds they replace but they still contribute to global warming with some like trifluoromethane having 11 700 times the warming potential of carbon dioxide 3 Their atmospheric concentrations and contribution to anthropogenic greenhouse gas emissions are rapidly increasing quantify causing international concern about their radiative forcing Contents 1 Chemistry 2 Environmental regulation 3 See also 4 ReferencesChemistry editFluorocarbons with few C F bonds behave similarly to the parent hydrocarbons but their reactivity can be altered significantly For example both uracil and 5 fluorouracil are colourless high melting crystalline solids but the latter is a potent anti cancer drug The use of the C F bond in pharmaceuticals is predicated on this altered reactivity 4 Several drugs and agrochemicals contain only one fluorine center or one trifluoromethyl group Environmental regulation editUnlike other greenhouse gases in the Paris Agreement hydrofluorocarbons are included in other international negotiations 5 In September 2016 the New York Declaration on Forests urged a global reduction in the use of HFCs 6 On 15 October 2016 due to these chemicals contribution to climate change negotiators from 197 nations meeting at a summit of the United Nations Environment Programme in Kigali Rwanda reached a legally binding accord the Kigali Amendment to phase down hydrofluorocarbons HFCs in an amendment to the Montreal Protocol 7 8 9 As of February 2020 16 U S states ban or are phasing down HFCs 10 COVID 19 relief legislation which included a measure that would require chemical manufacturers to phase down the production and use of HFCs was passed by the United States House of Representatives and United States Senate on December 21 2020 11 The U S Environmental Protection Agency signed a final rule phasing down HFCs on 23 September 2021 12 See also editGreenhouse gas Sources comparative chartReferences edit nbsp Scholia has a chemical class profile for Hydrofluorocarbon Zaelke Durwood Borgford Parnell Nathan Andersen Stephen 11 January 2018 Primer on HFCs PDF Kristin Campbell Xiaopu Sun Dennis Clare Claire Phillips Stela Herschmann Yuzhe PengLing Alex Milgroom Nancy J Sherman Institute for Governance amp Sustainable Development IGSD 5 a href Template Cite journal html title Template Cite journal cite journal a Cite journal requires journal help Milman Oliver 22 September 2016 100 countries push to phase out potentially disastrous greenhouse gas The Guardian London UK Retrieved 22 September 2016 Han Wenfeng Li Ying Tang Haodong Liu Huazhang 2012 Treatment of the potent greenhouse gas CHF3 An overview Journal of Fluorine Chemistry 140 7 16 doi 10 1016 j jfluchem 2012 04 012 G Siegemund W Schwertfeger A Feiring B Smart F Behr H Vogel B McKusick Fluorine Compounds Organic in Ullmann s Encyclopedia of Industrial Chemistry 2005 Wiley VCH Weinheim doi 10 1002 14356007 a11 349 Davenport Carol 23 July 2016 A Sequel to the Paris Climate Accord Takes Shape in Vienna New York Times Retrieved 17 August 2016 The New York Declaration of the Coalition to Secure an Ambitious HFC Amendment Washington DC US Department of State 22 September 2016 Retrieved 22 September 2016 Johnston Chris Milman Oliver Vidal John 15 October 2016 Climate change global deal reached to limit use of hydrofluorocarbons The Guardian Retrieved 15 October 2016 Climate change Monumental deal to cut HFCs fastest growing greenhouse gases BBC News 15 October 2016 Retrieved 15 October 2016 Nations Fighting Powerful Refrigerant That Warms Planet Reach Landmark Deal New York Times 15 October 2016 Retrieved 15 October 2016 Baker Administration Planning Rule To Ban Hydrofluorocarbons Davenport Coral 2020 12 22 Congress included climate change legislation in its coronavirus relief deal The New York Times ISSN 0362 4331 Retrieved 2020 12 22 Volcovici Valerie 2021 09 23 Biden administration takes aim at climate warming gas Yahoo News Retrieved 2021 09 23 Retrieved from https en wikipedia org w index php title Hydrofluorocarbon amp oldid 1185455399, wikipedia, wiki, book, books, library,
