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{{Short description|Type of organic chemical}}
A '''perfluorinated compound''' ('''PFC''') per- or polyfluoroalkyl chemical is an [[organofluorine compound]] containing only [[carbon-fluorine bond]]s (no C-H bonds) and C-C bonds but also other heteroatoms. PFCs, also known as perfluorinated chemicals, have properties that represent a blend of [[fluorocarbon]]s (containing only C-F and C-C bonds) and the parent functionalized organic species. For example, [[perfluorooctanoic acid]] functions as a carboxylic acid but with strongly altered surfactant and hydrophobic characteristics.<ref>Günter Siegemund, Werner Schwertfeger, Andrew Feiring, Bruce Smart, Fred Behr, Herward Vogel, Blaine McKusick "Fluorine Compounds, Organic" Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2002. {{DOI|10.1002/14356007.a11_349}}</ref> Fluorosurfactants are ubiquitously used in teflon, water resistant textiles and [[fire-fighting foam]].
[[File:Pentafluorophenol.svg|thumb|upright|[[Pentafluorophenol]], a perfluorinated compound.]]

PFCs have properties that result from the presence of [[fluorocarbon]]s (containing only C-F and C-C bonds) and the functional group. Common functional groups in PFCs are [[alcohol|OH]], [[perfluorocarboxylic acid|CO<sub>2</sub>H]], [[chlorofluorocarbons|chlorine]], [[perfluoroether|O]], and [[sulfonic acid|SO<sub>3</sub>H]].
A '''perfluorinated compound''' ('''PFC''') or '''perfluoro compound''' is an [[Organofluorine chemistry|organofluorine compound]] that lacks C-H bonds. Many perfluorinated compounds have properties that are quite different from their C-H containing analogues. Common functional groups in PFCs are [[Alcohol (chemistry)|OH]], [[Perfluorinated carboxylic acid|CO<sub>2</sub>H]], [[Chlorofluorocarbon|chlorine]], [[perfluoroether|O]], and [[sulfonic acid|SO<sub>3</sub>H]]. [[Electrochemical fluorination|Electrofluorination]] is the predominant method for PFC production. Due to their chemical stability, some of these perfluorinated compounds [[Bioaccumulation|bioaccumulate]].


==Applications==
==Applications==
Perfluorinated compounds are used ubiquitously: For example, fluorosurfactants are widely used in the production of [[teflon]] and related fluorinated polymers. They have been used to confer [[hydrophobicity]], stain-resistance to fabrics and as [[Firefighting foam|fire-fighting foam]].<ref>{{Cite web|url=http://www.sfei.org/sites/default/files/general_content/PFOS_profile_0.pdf|title=Profile - Perfluorooctane Sulfonate (PFOS)|last=Sedlak|first=Meg|date=October 2016|website=sfei.org|publisher=San Francisco Estuary Institute|access-date=2 November 2016}}</ref> [[Fluorosurfactant]]s powerfully reduce [[surface tension]] by concentrating at the liquid-air interface due to the lipophobicity of fluorocarbons. [[Chlorofluorocarbons]] were formerly used as refrigerants until they were implicated in [[ozone depletion|ozone degradation]].
One class of perfluorinated compounds, the fluorosurfactants, are widely used in the production of [[teflon]] (PTFE) and related fluorinated polymers. They also have been used to confer [[hydrophobicity]] and stain-resistance to fabrics. They are components of [[Firefighting foam|fire-fighting foam]].<ref>{{Cite web|url=http://www.sfei.org/sites/default/files/general_content/PFOS_profile_0.pdf|title=Profile - Perfluorooctane Sulfonate (PFOS)|last=Sedlak|first=Meg|date=October 2016|website=sfei.org|publisher=San Francisco Estuary Institute|access-date=2 November 2016}}</ref> [[Fluorosurfactant]]s (PFAS) reduce [[surface tension]] by concentrating at the liquid-air interface due to the ''lipo''phobicity of polyfluorocarbons.
[[Chlorofluorocarbons]] are perfluorinated compounds that were formerly used as refrigerants ([[Freon]]) until they were implicated in [[ozone depletion|ozone degradation]].


== Production ==
== Production ==
A common industrial method for synthesizing perflurocompounds is [[electrofluorination]].
Fluorine-containing compounds are derived from the mineral [[Fluorite|fluorspar]], which is the chemical compound [[Calcium fluoride|CaF<sub>2</sub>]]. There are examples of organisms that possess fluorine-containing compounds in their biochemistry and examples where organisms can be used to synthesize fluorinated compounds,<ref name="Murphy2003">Murphy CD, Schaffrath C, O'Hagan D.: [https://www.ncbi.nlm.nih.gov/pubmed/12738270 "Fluorinated natural products: the biosynthesis of fluoroacetate and 4-fluorothreonine in ''Streptomyces cattleya''"] Chemosphere. 2003 Jul;52(2):455-61.</ref> but the vast majority are man-made. The synthesis of perfluorinated compounds involves the use of F<sub>2</sub> and HF reagents that are derived from natural product CaF<sub>2.</sub> A common industrial method for synthesizing perflurocompounds involves direct fluorination of organic compounds using F<sub>2</sub> gas, where C-H bonds are replaced by C-F bonds accompanied by the formation of HF.<ref>{{Citation|last=Lagow|first=Richard J.|title=Direct Fluorination: A "New" Approach to Fluorine Chemistry|date=2007-03-09|work=Progress in Inorganic Chemistry|pages=161–210|publisher=John Wiley & Sons, Inc.|language=en|doi=10.1002/9780470166277.ch3|isbn=9780470166277|last2=Margrave|first2=John L.}}</ref>


==Classes of PFCs by functional group==
==Examples by functional group==
⚫
===Perfluorinated alkyl halides===
{{prose|section|date=September 2015}}
⚫
*[[Trifluoroiodomethane]], an [[alkylating]] agent.
Representative members of this large family of compounds are listed below. Also numerous are compounds that contain many fluoride centers but also some hydrogen, e.g., [[trifluoroethanol]].
⚫
*[[Pentafluoroethyl iodide]], an alkylating agent.
⚫
*[[Perfluorooctyl bromide]], or ''perflubron'', a [[contrast medium]] for [[magnetic resonance imaging]] (MRI), [[CT scan|computed tomography]] (CT) and [[sonography]]; fluid used in [[liquid breathing]].
⚫
*[[Dichlorodifluoromethane]], a refrigerant.


===Perfluoroalkenes===
⚫
===Perfluorinated alkyl and aryl halides===
*[[Tetrafluoroethylene]], precursor to [[polytetrafluoroethylene]] (PTFE).

*[[Chlorotrifluoroethylene]], [[refrigerant]] and precursor to [[polychlorotrifluoroethylene]] (PCTFE).
⚫
*[[Trifluoroiodomethane]], an alkylating agent
⚫
*[[Dichlorodifluoroethylene]] (three isomers).
⚫
*[[Pentafluoroethyl iodide]], an alkylating agent
⚫
*[[Perfluorooctyl bromide]] (perflubron) is a contrast medium for magnetic resonance imaging, computer tomography and sonography. It has also been used in [[liquid breathing]].
⚫
*[[Dichlorodifluoromethane]], refrigerant

===Fluorochloroalkenes===
*[[Chlorotrifluoroethylene]], monomer
⚫
*[[Dichlorodifluoroethylene]] (three isomers), monomers


===Perfluoroethers and epoxides===
===Perfluoroethers and epoxides===
{{Main|Perfluoroether}}
{{main article|Fluoroether}}
*[[hexafluoropropylene oxide]], precursor to perfluoromethyl vinyl ether (CF<sub>2</sub>=CFOCF<sub>3</sub>), a useful [[monomer]]
*[[Hexafluoropropylene oxide]], precursor to perfluoromethyl vinyl ether (CF<sub>2</sub>=CFOCF<sub>3</sub>), the monomer precursor to [[Krytox]], perfluorinated polyether used in special oils and greases.
*[[Krytox]], perfluorinated polyether used in special greases


===Perfluoroalcohols===
===Perfluoroalcohols===
{{main|Fluoroalcohol}}
{{Main|Fluoroalcohol}}
*[[Nonafluoro-tert-butyl alcohol]]
⚫
*[[Pentafluorophenol]], a moderately strong acid
*[[Perfluorotriethylcarbinol]]
⚫
Primary and secondary perfluorinated alcohols are unstable with respect to dehydrofluorination.
⚫
*[[Pentafluorophenol]], a moderately strong acid.
⚫
Primary and secondary perfluorinated alcohols are unstable with respect to [[Dehydrohalogenation|dehydrofluorination]].


===Perfluoroamines===
===Perfluoroamines===
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===Perfluoroketones===
===Perfluoroketones===
*[[Hexafluoroacetone]], building block in organofluorine chemistry.
*[[Hexafluoroacetone]], a building block in [[organofluorine chemistry]].


===Perfluorocarboxylic acids===
===Perfluorocarboxylic acids===
{{Main article|Perfluorinated carboxylic acid}}
{{Main|Perfluorinated carboxylic acid}}
*[[Trifluoroacetic acid]], a moderately strong acid useful in organic chemistry
*[[Trifluoroacetic acid]], a moderately strong acid useful in organic chemistry.
*[[Heptafluorobutyric acid]], a moderately strong acid that is useful in organic and analytical chemistry
*[[Heptafluorobutyric acid]], a moderately strong acid that is useful in organic and analytical chemistry.
*[[Pentafluorobenzoic acid]], a moderately strong acid of interest in research community
*[[Pentafluorobenzoic acid]], a moderately strong acid of interest in research community.
*[[perfluorooctanoic acid]] (PFOA), surfactant used to make [[fluoropolymer]]s such as [[Teflon]]
*[[Perfluorooctanoic acid]] (PFOA),a [[surfactant]] used to make [[fluoropolymer]]s such as [[Teflon]].
*[[perfluorononanoic acid]] (PFNA), [[surfactant]] in the [[emulsion polymerization]] of fluoropolymers, like PFOA.
*[[Perfluorononanoic acid]] (PFNA), a surfactant in the [[emulsion polymerization]] of fluoropolymers, like PFOA.


===Perfluoronitriles and isonitriles===
===Perfluoronitriles and isonitriles===
*[[Trifluoromethylisocyanide]], the simplest perfluorinated isonitrile.
*[[Trifluoromethylisocyanide]], the simplest perfluorinated isonitrile.
*Trifluoromethylacetonitrile, the simplest perfluorinated nitrile
*Trifluoromethylacetonitrile, the simplest perfluorinated nitrile.


===Perfluorosulfonic acids and related derivatives===
===Perfluorosulfonic acids and related derivatives===
*[[Triflic acid]], a useful strong acid
*[[Triflic acid]], a useful strong acid
*[[perfluorobutanesulfonic acid]] (PFBS) used as a replacement for PFOS in 3M's reformulated Scotchgard.
*[[perfluorobutanesulfonic acid]] (PFBS) used as a replacement for PFOS in [[3M]]'s reformulated [[Scotchgard]].
*[[perfluorobutane sulfonamide]] (FBSA), sulfonamide derivative of PFBS.
*[[perfluorooctanesulfonyl fluoride]] (POSF), precursor to PFOS-based compounds.
*[[perfluorooctanesulfonyl fluoride]] (POSF), precursor to PFOS-based compounds.
*[[perfluorooctanesulfonamide]] (PFOSA), used in 3M's Scotchgard formulation.
*[[perfluorooctanesulfonamide]] (PFOSA), used in 3M's Scotchgard formulation.
*[[perfluorooctanesulfonic acid]] (PFOS), used in the semiconductor industry, [[3M]]'s former [[Scotchgard]] formulation, and 3M's former fire-fighting foam mixture.
*[[perfluorooctanesulfonic acid]] (PFOS), used in the semiconductor industry, 3M's former Scotchgard formulation, and 3M's former fire-fighting foam mixture.


===Perfluorinated aryl borates===
===Perfluorinated aryl borates===
*Na[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>], salt of a [[weakly coordinating anion]].
*[[Tetrakis(3,5-bis(trifluoromethyl)phenyl)borate|Na[B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub>]]], salt of a [[weakly coordinating anion]].
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<ref>Guo Z, Liu X, Krebs KA (March 2009). {{cite web
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|title=Perfluorocarboxylic Acid Content in 116 Articles of Commerce
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[[Polychlorotrifluoroethylene]] ([CFClCF<sub>2</sub>]<sub>n</sub>)
[[Polychlorotrifluoroethylene]] ([CFClCF<sub>2</sub>]<sub>n</sub>)
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PFCs persist in the environment as [[persistent organic pollutant]]s, but unlike [[Polychlorinated biphenyl|PCB]]s, they are not known to degrade by any natural processes due to the strength of the [[carbon–fluorine bond]].<ref>{{cite news
PFCs persist in the environment as [[persistent organic pollutant]]s, but unlike [[Polychlorinated biphenyl|PCB]]s, they are not known to degrade by any natural processes due to the strength of the [[carbon–fluorine bond]].<ref>{{cite news
|first=Jennifer 8. |last=Lee |authorlink=Jennifer 8. Lee
|first=Jennifer 8. |last=Lee |author-link=Jennifer 8. Lee
|title=E.P.A. Orders Companies to Examine Effects of Chemicals
|title=E.P.A. Orders Companies to Examine Effects of Chemicals
|work=The New York Times |date=15 April 2003 |accessdate=15 May 2009
|work=The New York Times |date=15 April 2003 |access-date=15 May 2009
|url=https://www.nytimes.com/2003/04/15/science/epa-orders-companies-to-examine-effects-of-chemicals.html}}</ref>
|url=https://www.nytimes.com/2003/04/15/science/epa-orders-companies-to-examine-effects-of-chemicals.html}}</ref>


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==Environmental and health concerns==
==Environmental and health concerns==
{{Main|Per- and polyfluoroalkyl substances#Health and environmental concerns}}

There are several examples of environmental and health concerns around the industrial production and use of perfluoroalkane compounds. The unique chemical stability of perfluorinated compounds is desirable, and many times required, for many material applications but is also cause for environmental and health concerns.
Several environmental and health concerns surround the industrial production and use of perfluoroalkane compounds. The exceptional stability of perfluorinated compounds is desirable from the applications perspective is also a cause for environmental and health concerns.


=== Perfluoroalkanes ===
=== Perfluoroalkanes ===
Low-boiling perfluoroalkanes are potent [[greenhouse gases]], in part due to their very long atmospheric lifetime. The environmental concerns for perflurocompound's are similar to [[chlorofluorocarbon]]<nowiki/>s and other [[Halocarbon|halogenated compounds]] used as refrigerants and fire suppression materials. The history of use, environmental impact, and recommendations for use are included in the [[Kyoto Protocol]].
Low-boiling perfluoroalkanes are potent [[greenhouse gases]], in part due to their very long atmospheric lifetime. The environmental concerns for perflurocompounds are similar to [[chlorofluorocarbon]]s and other [[Halocarbon|halogenated compounds]] used as refrigerants and fire suppression materials. The history of use, environmental impact, and recommendations for use are included in the [[Kyoto Protocol]].


===Fluorosurfactants===
===Fluorosurfactants===
The fluorocarbons [[PFOA]] (perfluorooctanoic acid) and [[PFOS]] (perfluorooctane sulfonate) have both been investigated by the EU and the [[United States Environmental Protection Agency]] (EPA) which regards them being harmful to the environment<ref name="US Environmental Protection Agency" />. Specifically, studies found that PFOS caused "unusual and serious effects in animal toxicity tests," that it was present around the world in humans and wildlife, and that it was highly persistent in the environment<ref>Auer, Charles, Frank Kover, James Aidala, Marks Greenwood. [http://www.epaalumni.org/hcp/toxics.pdf “Toxic Substances: A Half Century of Progress.”] EPA Alumni Association. March 2016.</ref>. (Similar concerns followed for PFOA.)
The fluorocarbons [[PFOA]] (perfluorooctanoic acid) and [[PFOS]] (perfluorooctane sulfonate) have both been investigated by the EU and the [[United States Environmental Protection Agency]] (EPA) which regards them being harmful to the environment.<ref name="US Environmental Protection Agency" /> Specifically, studies found that PFOS caused "unusual and serious effects in animal toxicity tests, that it was present around the world in humans and wildlife, and that it was highly persistent in the environment."<ref>Auer, Charles, Frank Kover, James Aidala, Marks Greenwood. [http://www.epaalumni.org/hcp/toxics.pdf “Toxic Substances: A Half Century of Progress.”] EPA Alumni Association. March 2016.</ref> (Similar concerns followed for PFOA.)


Fluorosurfactants tend to [[bioaccumulate]], since they are extremely stable and can be stored in the bodies of humans and animals. Examples include PFOA and PFOS, frequently present in water resistant textiles and sprays conferring water resistant properties to textiles and [[fire-fighting foam]].<ref name="US Environmental Protection Agency">{{cite web|last=US Environmental Protection Agency|title=FAQ|url=http://www.epa.gov/oppt/pfoa/pubs/faq.html#risks|website=Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers|accessdate=11 May 2011}}</ref> Data from animal studies of PFOA indicate that it can cause several types of tumors and neonatal death and may have toxic effects on the immune, liver, and endocrine systems. {{as of |2010}} data on the human health effects of PFOA were sparse.<ref name="PFOA">{{cite journal |last1 = Steenland |first1 = Kyle |last2 = Fletcher |first2 = Tony |last3 = Savitz |first3 = David A. |title = Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA) |doi = 10.1289/ehp.0901827 |pmc = 2920088 |pmid = 20423814 |year = 2010 |pages = 1100–8 |issue = 8 |volume = 118 |journal = Environmental Health Perspectives}}</ref>
Fluorosurfactants tend to [[bioaccumulate]], since they are extremely stable and can be stored in the bodies of humans and animals. Examples include PFOA and PFOS, frequently present in water-resistant textiles and sprays conferring water-resistant properties to textiles and [[fire-fighting foam]].<ref name="US Environmental Protection Agency">{{cite web|last=US Environmental Protection Agency|title=FAQ|url=http://www.epa.gov/oppt/pfoa/pubs/faq.html#risks|website=Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers|access-date=11 May 2011}}</ref> Data from animal studies of PFOA indicate that it can cause several types of tumors and neonatal death and may have toxic effects on the immune, liver, and endocrine systems. {{as of |2010}} data on the human health effects of PFOA were sparse.<ref name="PFOA">{{cite journal |last1 = Steenland |first1 = Kyle |last2 = Fletcher |first2 = Tony |last3 = Savitz |first3 = David A. |title = Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA) |doi = 10.1289/ehp.0901827 |pmc = 2920088 |pmid = 20423814 |year = 2010 |pages = 1100–8 |issue = 8 |volume = 118 |journal = Environmental Health Perspectives}}</ref>


As of 2015, the U.S. Air Force had been testing 82 former and active US military installations for fluorosurfactants contained in fire fighting foam.<ref name=lin>{{cite news|author1=Associated Press|title=Grissom officials: Well tests show no chemical pollution|url=http://wishtv.com/2015/09/17/grissom-officials-well-tests-show-no-chemical-pollution/|accessdate=19 September 2015|work=LIN Television Corporation|date=19 September 2015}}</ref> In 2015, PFCs were found in groundwater at [[Naval Air Station Brunswick]], Maine and [[Grissom Air Reserve Base]], Indiana, and in well water at [[Pease Air Force Base#Environmental issues|Pease Air Force Base]], New Hampshire, where 500 people including children had blood tests as part of a bio-monitoring plan through the state Department of Health and Human Services. The U.S. Department of Defense's research programs have been trying to define nature and extent of PFAS contamination at U.S. military sites, especially in groundwater.<ref>Strategic Environmental Research and Development Program (SERDP), Environmental Security Technology Certification Program (ESTCP) [https://serdp-estcp.org/Tools-and-Training/Webinar-Series/01-28-2016 Per- and Polyfluoroalkyl Substances (PFASs): Analytical and Characterization Frontiers] webinarslides, January 28, 2016</ref>
As of 2015, the U.S. Air Force had been testing 82 former and active US military installations for fluorosurfactants contained in fire fighting foam.<ref name=lin>{{cite news|agency=Associated Press|title=Grissom officials: Well tests show no chemical pollution|url=http://wishtv.com/2015/09/17/grissom-officials-well-tests-show-no-chemical-pollution/|access-date=19 September 2015|work=LIN Television Corporation|date=19 September 2015}}</ref> In 2015, PFCs were found in groundwater at [[Naval Air Station Brunswick]], Maine and [[Grissom Air Reserve Base]], Indiana, and in well water at [[Pease Air Force Base#Environmental issues|Pease Air Force Base]], New Hampshire, where 500 people including children had blood tests as part of a bio-monitoring plan through the state Department of Health and Human Services. The U.S. Department of Defense's research programs have been trying to define nature and extent of PFAS contamination at U.S. military sites, especially in groundwater.<ref>Strategic Environmental Research and Development Program (SERDP), Environmental Security Technology Certification Program (ESTCP) [https://serdp-estcp.org/Tools-and-Training/Webinar-Series/01-28-2016 Per- and Polyfluoroalkyl Substances (PFASs): Analytical and Characterization Frontiers] webinarslides, January 28, 2016</ref>


A 2018 report to Congress indicated that "at least 126 drinking water systems on or near military bases" were contaminated with PFAS compounds.<ref>{{Cite web|url=https://www.propublica.org/article/suppressed-study-the-epa-underestimated-dangers-of-widespread-chemicals|title=Suppressed Study: The EPA Underestimated Dangers of Widespread Chemicals|last=Lustgarten|first=Abrahm|date=2018-06-20|website=ProPublica|language=en-us|others=Lisa Song,Talia Buford|archive-url=|archive-date=|dead-url=|access-date=2018-06-23}}</ref><ref>{{Cite news|url=https://www.airforcetimes.com/news/your-air-force/2017/07/31/air-force-wont-pay-for-towns-water-contamination-costs/|title=Air Force won't pay for towns' water contamination costs|last=Associated Press|first=|date=2017-07-31|work=Air Force Times|access-date=2018-06-23|language=en-US}}</ref>
A 2018 report to Congress indicated that "at least 126 drinking water systems on or near military bases" were contaminated with PFAS compounds.<ref>{{Cite web|url=https://www.propublica.org/article/suppressed-study-the-epa-underestimated-dangers-of-widespread-chemicals|title=Suppressed Study: The EPA Underestimated Dangers of Widespread Chemicals|last=Lustgarten|first=Abrahm|date=2018-06-20|website=ProPublica|language=en-us|others=Lisa Song, Talia Buford|access-date=2018-06-23}}</ref><ref>{{Cite news|url=https://www.airforcetimes.com/news/your-air-force/2017/07/31/air-force-wont-pay-for-towns-water-contamination-costs/|title=Air Force won't pay for towns' water contamination costs|last=Associated Press|date=2017-07-31|work=Air Force Times|access-date=2018-06-23|language=en-US}}</ref>


A 2016 study found unsafe<ref>Above the minimum reporting levels required by the EPA − 70 parts per trillion (ng/L) for PFOS and PFOA</ref> levels of fluorosurfactants in 194 out of 4,864 water supplies in 33 U.S. states. Covering two-thirds of drinking water supplies in the United States, the study found thirteen states accounted for 75% of the detections. In order of frequency, these were: California, New Jersey, North Carolina, Alabama, Florida, Pennsylvania, Ohio, New York, Georgia, Minnesota, Arizona, Massachusetts, and Illinois. Firefighting foam was singled out as a major contributor.<ref>[http://phys.org/news/2016-08-unsafe-toxic-chemicals-million-americans.html Unsafe levels of toxic chemicals found in drinking water for 6 million Americans] Science X network, phys.org, August 9, 2016</ref>
A 2016 study found unsafe<ref>Above the minimum reporting levels required by the EPA − 70 parts per trillion (ng/L) for PFOS and PFOA</ref> levels of fluorosurfactants in 194 out of 4,864 water supplies in 33 U.S. states. Covering two-thirds of drinking water supplies in the United States, the study found thirteen states accounted for 75% of the detections. In order of frequency, these were: California, New Jersey, North Carolina, Alabama, Florida, Pennsylvania, Ohio, New York, Georgia, Minnesota, Arizona, Massachusetts, and Illinois. [[Firefighting foam]] was singled out as a major contributor.<ref>[http://phys.org/news/2016-08-unsafe-toxic-chemicals-million-americans.html Unsafe levels of toxic chemicals found in drinking water for 6 million Americans] Science X network, phys.org, August 9, 2016</ref>


==See also==
==See also==
*[[Per- and polyfluoroalkyl substances]]
*[[Fluorosurfactant]]s
*[[Fluorocarbons]]
*[[Fluorocarbons]]


==References==
==References==
{{reflist}}
{{Reflist}}


== External links ==
== External links ==
* {{commons category-inline|Perfluorinated compounds}}
* {{Commons category-inline|Perfluorinated compounds}}


{{HealthIssuesOfPlastics}}
{{HealthIssuesOfPlastics}}
{{Xenoestrogens}}
{{Xenoestrogens}}
{{Authority control}}


{{DEFAULTSORT:Perfluorinated Compounds}}
{{DEFAULTSORT:Perfluorinated Compounds}}
[[Category:Perfluorinated compounds| ]]
[[Category:Perfluorinated compounds| ]]
[[Category:Xenoestrogens]]
[[Category:Xenoestrogens]]
[[Category:Endocrine disruptors]]
[[Category:Pollutants]]
[[Category:Environment and health]]

Revision as of 08:42, 22 May 2024

Pentafluorophenol, a perfluorinated compound.

A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound that lacks C-H bonds. Many perfluorinated compounds have properties that are quite different from their C-H containing analogues. Common functional groups in PFCs are OH, CO2H, chlorine, O, and SO3H. Electrofluorination is the predominant method for PFC production. Due to their chemical stability, some of these perfluorinated compounds bioaccumulate.

Applications

One class of perfluorinated compounds, the fluorosurfactants, are widely used in the production of teflon (PTFE) and related fluorinated polymers. They also have been used to confer hydrophobicity and stain-resistance to fabrics. They are components of fire-fighting foam.[1] Fluorosurfactants (PFAS) reduce surface tension by concentrating at the liquid-air interface due to the lipophobicity of polyfluorocarbons.

Chlorofluorocarbons are perfluorinated compounds that were formerly used as refrigerants (Freon) until they were implicated in ozone degradation.

Production

A common industrial method for synthesizing perflurocompounds is electrofluorination.

Examples by functional group

Perfluorinated alkyl halides

Perfluoroalkenes

Perfluoroethers and epoxides

Main article: Perfluoroether
  • Hexafluoropropylene oxide, precursor to perfluoromethyl vinyl ether (CF2=CFOCF3), the monomer precursor to Krytox, perfluorinated polyether used in special oils and greases.

Perfluoroalcohols

Main article: Fluoroalcohol

Primary and secondary perfluorinated alcohols are unstable with respect to dehydrofluorination.

Perfluoroamines

Perfluoroketones

Perfluorocarboxylic acids

Main article: Perfluorinated carboxylic acid

Perfluoronitriles and isonitriles

  • Trifluoromethylisocyanide, the simplest perfluorinated isonitrile.
  • Trifluoromethylacetonitrile, the simplest perfluorinated nitrile.

Perfluorinated aryl borates

Environmental and health concerns

Main article: Per- and polyfluoroalkyl substances § Health and environmental concerns

Several environmental and health concerns surround the industrial production and use of perfluoroalkane compounds. The exceptional stability of perfluorinated compounds is desirable from the applications perspective is also a cause for environmental and health concerns.

Perfluoroalkanes

Low-boiling perfluoroalkanes are potent greenhouse gases, in part due to their very long atmospheric lifetime. The environmental concerns for perflurocompounds are similar to chlorofluorocarbons and other halogenated compounds used as refrigerants and fire suppression materials. The history of use, environmental impact, and recommendations for use are included in the Kyoto Protocol.

Fluorosurfactants

The fluorocarbons PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate) have both been investigated by the EU and the United States Environmental Protection Agency (EPA) which regards them being harmful to the environment.[2] Specifically, studies found that PFOS caused "unusual and serious effects in animal toxicity tests, that it was present around the world in humans and wildlife, and that it was highly persistent in the environment."[3] (Similar concerns followed for PFOA.)

Fluorosurfactants tend to bioaccumulate, since they are extremely stable and can be stored in the bodies of humans and animals. Examples include PFOA and PFOS, frequently present in water-resistant textiles and sprays conferring water-resistant properties to textiles and fire-fighting foam.[2] Data from animal studies of PFOA indicate that it can cause several types of tumors and neonatal death and may have toxic effects on the immune, liver, and endocrine systems. As of 2010 data on the human health effects of PFOA were sparse.[4]

As of 2015, the U.S. Air Force had been testing 82 former and active US military installations for fluorosurfactants contained in fire fighting foam.[5] In 2015, PFCs were found in groundwater at Naval Air Station Brunswick, Maine and Grissom Air Reserve Base, Indiana, and in well water at Pease Air Force Base, New Hampshire, where 500 people including children had blood tests as part of a bio-monitoring plan through the state Department of Health and Human Services. The U.S. Department of Defense's research programs have been trying to define nature and extent of PFAS contamination at U.S. military sites, especially in groundwater.[6]

A 2018 report to Congress indicated that "at least 126 drinking water systems on or near military bases" were contaminated with PFAS compounds.[7][8]

A 2016 study found unsafe[9] levels of fluorosurfactants in 194 out of 4,864 water supplies in 33 U.S. states. Covering two-thirds of drinking water supplies in the United States, the study found thirteen states accounted for 75% of the detections. In order of frequency, these were: California, New Jersey, North Carolina, Alabama, Florida, Pennsylvania, Ohio, New York, Georgia, Minnesota, Arizona, Massachusetts, and Illinois. Firefighting foam was singled out as a major contributor.[10]

See also

References

  1. ^ Sedlak, Meg (October 2016). "Profile - Perfluorooctane Sulfonate (PFOS)" (PDF). sfei.org. San Francisco Estuary Institute. Retrieved 2 November 2016.
  2. ^ a b US Environmental Protection Agency. "FAQ". Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers. Retrieved 11 May 2011.
  3. ^ Auer, Charles, Frank Kover, James Aidala, Marks Greenwood. “Toxic Substances: A Half Century of Progress.” EPA Alumni Association. March 2016.
  4. ^ Steenland, Kyle; Fletcher, Tony; Savitz, David A. (2010). "Epidemiologic Evidence on the Health Effects of Perfluorooctanoic Acid (PFOA)". Environmental Health Perspectives. 118 (8): 1100–8. doi:10.1289/ehp.0901827. PMC 2920088. PMID 20423814.
  5. ^ "Grissom officials: Well tests show no chemical pollution". LIN Television Corporation. Associated Press. 19 September 2015. Retrieved 19 September 2015.
  6. ^ Strategic Environmental Research and Development Program (SERDP), Environmental Security Technology Certification Program (ESTCP) Per- and Polyfluoroalkyl Substances (PFASs): Analytical and Characterization Frontiers webinarslides, January 28, 2016
  7. ^ Lustgarten, Abrahm (2018-06-20). "Suppressed Study: The EPA Underestimated Dangers of Widespread Chemicals". ProPublica. Lisa Song, Talia Buford. Retrieved 2018-06-23.
  8. ^ Associated Press (2017-07-31). "Air Force won't pay for towns' water contamination costs". Air Force Times. Retrieved 2018-06-23.
  9. ^ Above the minimum reporting levels required by the EPA − 70 parts per trillion (ng/L) for PFOS and PFOA
  10. ^ Unsafe levels of toxic chemicals found in drinking water for 6 million Americans Science X network, phys.org, August 9, 2016
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