Perfluorinated compound

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Pentafluorophenol, a perfluorinated compound. Pentafluorophenol.svg
Pentafluorophenol, a perfluorinated compound.

A perfluorinated compound (PFC) or perfluoro compound is an organofluorine compound lacking 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.

Contents

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

Perfluoroalcohols

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

Perfluoroamines

Perfluoroketones

Perfluorocarboxylic acids

Perfluoronitriles and isonitriles

Perfluorinated aryl borates

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

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

Related Research Articles

<span class="mw-page-title-main">Polytetrafluoroethylene</span> Synthetic polymer

Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene and is a PFAS that has numerous applications. The commonly known brand name of PTFE-based composition is Teflon by Chemours, a spin-off from DuPont, which originally discovered the compound in 1938.

<span class="mw-page-title-main">Perfluorooctanoic acid</span> Perfluorinated carboxylic acid

Perfluorooctanoic acid is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes and as a material feedstock. PFOA is considered a surfactant, or fluorosurfactant, due to its chemical structure, which consists of a perfluorinated, n-heptyl "tail group" and a carboxylate "head group". The head group can be described as hydrophilic while the fluorocarbon tail is both hydrophobic and lipophobic.

<span class="mw-page-title-main">Perfluorooctanesulfonic acid</span> Fluorosurfactant and persistent organic pollutant

Perfluorooctanesulfonic acid (PFOS) is a chemical compound having an eight-carbon fluorocarbon chain and a sulfonic acid functional group and thus a perfluorosulfonic acid. It is an anthropogenic (man-made) fluorosurfactant, now regarded as a global pollutant. PFOS was the key ingredient in Scotchgard, a fabric protector made by 3M, and related stain repellents. The acronym "PFOS" refers to the parent sulfonic acid and to various salts of perfluorooctanesulfonate. These are all colorless or white, water-soluble solids. Although of low acute toxicity, PFOS has attracted much attention for its pervasiveness and environmental impact. It was added to Annex B of the Stockholm Convention on Persistent Organic Pollutants in May 2009.

<span class="mw-page-title-main">Firefighting foam</span> Foam used for fire suppression

Firefighting foam is a foam used for fire suppression. Its role is to cool the fire and to coat the fuel, preventing its contact with oxygen, thus achieving suppression of the combustion. Firefighting foam was invented by the Russian engineer and chemist Aleksandr Loran in 1902.

<span class="mw-page-title-main">Microwave popcorn</span> Type of convenience food

Microwave popcorn is a convenience food consisting of unpopped popcorn in an enhanced, sealed paper bag intended to be heated in a microwave oven. In addition to the dried corn, the bags typically contain cooking oil with sufficient saturated fat to solidify at room temperature, one or more seasonings, and natural or artificial flavorings or both.

Scotchgard is a 3M brand of products, a stain and durable water repellent applied to fabric, furniture, and carpets to protect them from stains. Scotchgard products typically rely on organofluorine chemicals as the main active ingredient along with petroleum distillate solvents.

Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.

<span class="mw-page-title-main">Per- and polyfluoroalkyl substances</span> Class of perfluorinated chemical compounds

Per- and polyfluoroalkyl substances (PFAS or PFASs) are a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl moiety, –CnF2n+1–. Beginning in 2021, the Organisation for Economic Co-operation and Development (OECD) expanded their terminology, stating that "PFASs are defined as fluorinated substances that contain at least one fully fluorinated methyl or methylene carbon atom (without any H/Cl/Br/I atom attached to it), i.e., with a few noted exceptions, any chemical with at least a perfluorinated methyl group (–CF3) or a perfluorinated methylene group (–CF2–) is a PFAS."

<span class="mw-page-title-main">Perfluorobutanesulfonic acid</span> Chemical compound

Perfluorobutanesulfonic acid (PFBS) is a PFAS chemical compound having a four-carbon fluorocarbon chain and a sulfonic acid functional group. It is stable and unreactive because of the strength of carbon–fluorine bonds. It can occur in the form of a colorless liquid or a corrosive solid. Its conjugate base is perfluorobutanesulfonate which functions as the hydrophobe in fluorosurfactants.

Fluorotelomers are fluorocarbon-based oligomers, or telomers, synthesized by telomerization. Some fluorotelomers and fluorotelomer-based compounds are a source of environmentally persistent perfluorinated carboxylic acids such as PFOA and PFNA, while others are under extended investigation.

<span class="mw-page-title-main">Perfluorooctanesulfonamide</span> Chemical compound

Perfluorooctanesulfonamide (PFOSA) is a synthetic organofluorine compound. It is a fluorocarbon derivative and a perfluorinated compound, having an eight-carbon chain and a terminal sulfonamide functional group. PFOSA, a persistent organic pollutant, was an ingredient in 3M's former Scotchgard formulation from 1956 until 2003, and the compound was used to repel grease and water in food packaging along with other consumer applications. It breaks down to form perfluorooctane sulfonate (PFOS). The perfluorooctanesulfonyl fluoride-based chemistry that was used to make sulfonamides like PFOSA was phased out by 3M in the United States (US) during 2000–2002 but it has grown in China by other producers.

<span class="mw-page-title-main">Perfluorooctanesulfonyl fluoride</span> Chemical compound

Perfluorooctanesulfonyl fluoride (POSF) is a synthetic perfluorinated compound with a sulfonyl fluoride functional group. It is used to make perfluorooctanesulfonic acid (PFOS) and PFOS-based compounds. These compounds have a variety of industrial and consumer uses, but POSF-derived substances ultimately degrade to form PFOS.

<i>The Devil We Know</i> 2018 documentary by Stephanie Soechtig

The Devil We Know is a 2018 investigative documentary film by director Stephanie Soechtig regarding allegations of health hazards from perfluorooctanoic acid, a key ingredient used in manufacturing Teflon, and DuPont's potential responsibility. PFAS are commonly found in every household, and in products as diverse as non-stick cookware, stain resistant furniture and carpets, wrinkle free and water repellant clothing, cosmetics, lubricants, paint, pizza boxes, popcorn bags, and many other everyday products.

<span class="mw-page-title-main">Biological aspects of fluorine</span>

Fluorine may interact with biological systems in the form of fluorine-containing compounds. Though elemental fluorine (F2) is very rare in everyday life, fluorine-containing compounds such as fluorite occur naturally as minerals. Naturally occurring organofluorine compounds are extremely rare. Man-made fluoride compounds are common and are used in medicines, pesticides, and materials. Twenty percent of all commercialized pharmaceuticals contain fluorine, including Lipitor and Prozac. In many contexts, fluorine-containing compounds are harmless or even beneficial to living organisms; in others, they are toxic.

<span class="mw-page-title-main">Water contamination in Lawrence and Morgan Counties, Alabama</span>

Water contamination in Lawrence and Morgan Counties, Alabama, revolves around the presence of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) in the water supply. After the US Environmental Protection Agency (EPA) released new health advisories in March 2016, there was concern over health risks of the levels of PFOA and PFOS present. The responses of different government officials, agencies, and companies raise questions as to whether or not there was any environmental injustice involved.

GenX is a Chemours trademark name for a synthetic, short-chain organofluorine chemical compound, the ammonium salt of hexafluoropropylene oxide dimer acid (HFPO-DA). It can also be used more informally to refer to the group of related fluorochemicals that are used to produce GenX. DuPont began the commercial development of GenX in 2009 as a replacement for perfluorooctanoic acid.

<span class="mw-page-title-main">Perfluorobutane sulfonamide</span> Chemical compound

Perfluorobutane sulfonamide, also known as FBSA or H-FBSA, is a perfluorinated surfactant. FBSA and its N-alkylated derivatives have been patented by 3M for use in acid etch solutions with low surface tension. According to the inventors, FBSA and its derivatives are expected to have a smaller tendency to accumulate in living organisms than their perfluorooctanyl analogs such as PFOS. Nevertheless, a 2015 study found FBSA in 32 out of 33 samples of Canadian fish.

This timeline of events related to per- and polyfluoroalkyl substances (PFASs) includes events related to the discovery, development, manufacture, marketing, uses, concerns, litigation, regulation, and legislation, involving the human-made PFASs. The timeline focuses on some perfluorinated compounds, particularly perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) and on the companies that manufactured and marketed them, mainly DuPont and 3M. An example of PFAS is the fluorinated polymer polytetrafluoroethylene (PTFE), which has been produced and marketed by DuPont under its trademark Teflon. GenX chemicals and perfluorobutanesulfonic acid (PFBS) are organofluorine chemicals used as a replacement for PFOA and PFOS.

<span class="mw-page-title-main">Perfluorohexanesulfonic acid</span> Chemical compound

Perfluorohexanesulfonic acid (PFHxS) is a synthetic chemical compound. It is one of many compounds collectively known as per- and polyfluoroalkyl substances (PFASs). It is an anionic fluorosurfactant and a persistent organic pollutant with bioaccumulative properties. Although the use of products containing PFHxS and other PFASs have been banned or are being phased out in many jurisdictions, it remains ubiquitous in many environments and within the general population, and is one of the most commonly detected PFASs.

Sulfluramid (N-EtFOSA) is a chemical compound from the group of sulfonic acid amides and per- and polyfluoroalkyl substances (PFASs) that is effective as an insecticide.

References

  1. Sedlak, Meg (October 2016). "Profile - Perfluorooctane Sulfonate (PFOS)" (PDF). sfei.org. San Francisco Estuary Institute. Retrieved 2 November 2016.
  2. 1 2 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