A perfluorinated compound is an organofluorine compound containing only carbon-fluorines and C-C bonds but also other heteroatoms. PFCs have properties that result from the presence of fluorocarbons and the functional group. Common functional groups in PFCs are OH, CO2H, chlorine, O, and SO3H.
Applications
Perfluorinated compounds are used ubiquitously: For example, fluorosurfactants are widely used in the production of teflon and related fluorinated polymers. They confer hydrophobicity and stain-resistance to fabrics. They are components of fire-fighting foam. Fluorosurfactants 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 until they were implicated in ozone degradation.
Production
A common industrial method for synthesizing perflurocompounds is electrofluorination.
Several environmental and health concerns surrround 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 and PFOS have both been investigated by the EU and the United States Environmental Protection Agency which regards them being harmful to the environment. 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. 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. 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. data on the human health effects of PFOA were sparse. 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. 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. A 2018 report to Congress indicated that "at least 126 drinking water systems on or near military bases" were contaminated with PFAS compounds. A 2016 study found unsafe 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.
