Editing Hydrofluorocarbon

{{short description|Synthetic organic compounds}}

[[File:Fluoromethane.svg|thumb|right|150px|[[Fluoromethane]], a hydrofluorocarbon.]]

'''Hydrofluorocarbons''' ('''HFCs''') are synthetic 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 [[chlorofluorocarbon]]s (CFCs) such as [[Dichlorodifluoromethane|R-12]], which were phased out from use by the [[Montreal Protocol]], and [[hydrochlorofluorocarbon]]s (HCFCs) such as [[Dichlorofluoromethane|R-21]] which are presently being phased out.<ref>{{Cite journal|last1=Zaelke|first1=Durwood|last2=Borgford-Parnell|first2=Nathan|last3=Andersen.|first3=Stephen|date=11 January 2018|others=Kristin Campbell, Xiaopu Sun, Dennis Clare, Claire Phillips, Stela Herschmann, Yuzhe PengLing, Alex Milgroom, Nancy J. Sherman.|title=Primer on HFCs|url=http://www.igsd.org/wp-content/uploads/2018/01/HFC-Primer-v11Jan18.pdf|publisher=Institute for Governance & Sustainable Development (IGSD)|pages=5}}</ref><ref name="milman-2016">
{{cite news
 | last        = Milman
 | first       = Oliver
 | title       = 100 countries push to phase out potentially disastrous greenhouse gas
 | date        = 22 September 2016
 | work        = The Guardian
 | location    = London, UK
 | url         = https://www.theguardian.com/environment/2016/sep/22/100-countries-phase-out-hydrofluorocarbons-greenhouse-gas
 | access-date = 22 September 2016
}}
</ref> HFCs are also used in insulating foams, aerosol propellants, as solvents and for fire protection.

HFCs may not harm the ozone layer as much as the compounds they replace, but they still contribute to [[global warming]] – with some like [[Fluoroform|trifluoromethane]] (CHF3 or R-23) having 11,700 times the warming potential of carbon dioxide.<ref>{{Cite journal|url=https://www.sciencedirect.com/science/article/abs/pii/S0022113912001315|title=Treatment of the potent greenhouse gas, CHF3—An overview|year=2012|doi=10.1016/j.jfluchem.2012.04.012|last1=Han|first1=Wenfeng|last2=Li|first2=Ying|last3=Tang|first3=Haodong|last4=Liu|first4=Huazhang|journal=Journal of Fluorine Chemistry|volume=140|pages=7–16|url-access=subscription}}</ref> HFC atmospheric concentrations and contribution to [[Human impact on the environment|anthropogenic]] [[greenhouse gas emissions]] are rapidly increasing – consumption rose from near zero in 1990 to 1.2 billion tons of carbon dioxide equivalent in 2010<ref>{{Citation |last=Toit |first=Louise du |title=Strengthening the Global Regulation of Hydrofluorocarbons under the Montreal Protocol |date=2023-12-01 |work=Reducing Emissions of Short-Lived Climate Pollutants |pages=90–124 |url=https://brill.com/display/book/9789004684089/BP000006.xml |access-date=2024-04-30 |publisher=Brill Nijhoff |language=en |doi=10.1163/9789004684089_006 |isbn=978-90-04-68408-9}}</ref> – causing international concern about their [[radiative forcing]].

==Chemistry==

Fluorocarbons with few [[Carbon–fluorine bond|C–F]] [[Chemical bond|bonds]] behave similarly to the parent [[hydrocarbon]]s, 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.<ref name=Ullmann>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}}</ref> Several drugs and [[agrochemical]]s contain only one fluorine center or one [[trifluoromethyl]] group.

==Environmental regulation==

Unlike other greenhouse gases in the [[Paris Agreement]], hydrofluorocarbons are included in other international negotiations.<ref>{{cite news |last=Davenport |first=Carol |date=23 July 2016 |title=A Sequel to the Paris Climate Accord Takes Shape in Vienna |url=https://www.nytimes.com/2016/07/24/world/europe/vienna-sequel-paris-climate-accord.html |newspaper=New York Times |access-date=17 August 2016}}</ref>

In September 2016, the [[New York Declaration on Forests]] urged a global reduction in the use of HFCs.<ref name="ny-declaration-on-hfcs-2016">
{{cite web
 | title = The New York Declaration of the Coalition to Secure an Ambitious HFC Amendment
 | date = 22 September 2016
 | publisher = US Department of State
 | location = Washington, DC
 | access-date = 22 September 2016
 | url = https://2009-2017.state.gov/e/oes/rls/pr/2016/262236.htm
}}
</ref> On 15 October 2016, due to these chemicals' contribution to [[global warming|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]].<ref>{{cite web|url=https://www.theguardian.com/environment/2016/oct/15/climate-change-environmentalists-hail-deal-to-limit-use-of-hydrofluorocarbons |title=Climate change: global deal reached to limit use of hydrofluorocarbons |website=The Guardian |first1=Chris |last1=Johnston |first2=Oliver |last2=Milman |first3=John |last3=Vidal |date=15 October 2016 |access-date=15 October 2016}}</ref><ref>{{cite web|url =https://www.bbc.co.uk/news/science-environment-37665529 |title=Climate change: 'Monumental' deal to cut HFCs, fastest growing greenhouse gases |publisher=BBC News |date=15 October 2016 |access-date=15 October 2016}}</ref><ref>{{cite web|url =https://www.nytimes.com/2016/10/15/world/africa/kigali-deal-hfc-air-conditioners.html |title= Nations, Fighting Powerful Refrigerant That Warms Planet, Reach Landmark Deal |work=New York Times |date=15 October 2016 |access-date=15 October 2016}}</ref> As of February 2020, 16 U.S. states ban or are phasing down HFCs.<ref>[https://www.wbur.org/earthwhile/2020/02/18/massachusetts-planninghydrofluorocarbon-hfc-ban Baker Administration Planning Rule To Ban Hydrofluorocarbons]</ref>

[[Coronavirus disease 2019|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.<ref>{{Cite news|last=Davenport|first=Coral|date=2020-12-22|title=Congress included climate change legislation in its coronavirus relief deal.|language=en-US|work=The New York Times|url=https://www.nytimes.com/2020/12/22/us/congress-included-climate-change-legislation-in-its-coronavirus-relief-deal.html|access-date=2020-12-22|issn=0362-4331}}</ref> The U.S. Environmental Protection Agency signed a final rule phasing down HFCs on 23 September 2021.<ref>{{Cite news|title=Biden administration takes aim at climate warming gas|url=https://news.yahoo.com/biden-administration-takes-aim-climate-092027109.html|last=Volcovici|first=Valerie|date=2021-09-23|access-date=2021-09-23|work=[[Yahoo! News]]}}</ref>

==See also==
* {{section link|Greenhouse gas|Sources}} - comparative chart

==References==
{{Scholia|chemical-class}}
{{Reflist}}

[[Category:Organofluorides]]