Aperfluorinated compound (PFC) orperfluoro compound is anorganofluorine 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 areOH,CO2H,chlorine,O, andSO3H.Electrofluorination is the predominant method for PFC production. Due to their chemical stability, some of these perfluorinated compoundsbioaccumulate.
One class of perfluorinated compounds, the fluorosurfactants, are widely used in the production ofteflon (PTFE) and related fluorinated polymers. They also have been used to conferhydrophobicity and stain-resistance to fabrics. They are components offire-fighting foam.[1]Fluorosurfactants (PFAS) reducesurface tension by concentrating at the liquid-air interface due to thelipophobicity of polyfluorocarbons.
Chlorofluorocarbons are also perfluorinated compounds, many of which were formerly used as refrigerants (Freon) until they were implicated inozone degradation.
A common industrial method for synthesizing perflurocompounds iselectrofluorination.
Someperfluoroheteroarenes are produced via saturative addition and then defluorinative rearomatization.[2]
Primary and secondary perfluorinated alcohols are unstable with respect todehydrofluorination.
Several environmental and health concerns surround the industrial production and use of perfluoroalkane compounds. The exceptional stability of perfluorinated compounds, while desirable from the applications perspective, is also a cause for environmental and health concerns.
Low-boiling perfluoroalkanes are potentgreenhouse gases, in part due to their very long atmospheric lifetime. The environmental concerns for perflurocompounds are similar tochlorofluorocarbons and otherhalogenated compounds used as refrigerants and fire suppression materials. The history of use, environmental impact, and recommendations for use are included in theKyoto Protocol.
The fluorocarbonsPFOA (perfluorooctanoic acid) andPFOS (perfluorooctane sulfonate) have both been investigated by the EU and theUnited States Environmental Protection Agency (EPA) which regards them being harmful to the environment.[3] 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."[4] (Similar concerns followed for PFOA.)
Fluorosurfactants tend tobioaccumulate, 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 andfire-fighting foam.[3] 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[update] data on the human health effects of PFOA were sparse.[5]
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.[6] In 2015, PFCs were found in groundwater atNaval Air Station Brunswick, Maine andGrissom Air Reserve Base, Indiana, and in well water atPease 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.[7]
A 2018 report to Congress indicated that "at least 126 drinking water systems on or near military bases" were contaminated with PFAS compounds.[8][9]
A 2016 study found unsafe[10] 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.[11]
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