A perfluorinated compound (PFC) is an organofluorine compound containing only carbon-fluorine bonds (no C-H bonds) and C-C bonds but also other heteroatoms. PFCs have properties that represent a blend of fluorocarbons (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.
- 1 Applications
- 2 Classes of PFCs by functional group
- 2.1 Perfluorinated alkyl and aryl halides
- 2.2 Fluorochloroalkenes
- 2.3 Perfluoroethers and epoxides
- 2.4 Perfluoroalcohols
- 2.5 Perfluoroamines
- 2.6 Perfluoroketones
- 2.7 Perfluorocarboxylic acids
- 2.8 Perfluoronitriles and isonitriles
- 2.9 Perfluorosulfonic acids and related derivatives
- 2.10 Perfluorinated aryl borates
- 3 Environmental and health concerns
- 4 See also
- 5 References
Many perfluorinated compounds are useful. For example, fluorosurfactants powerfully reduce surface tension by concentrating at the liquid-air interface due to the lipophobicity of fluorocarbons, due to the polar functional group added to the fluorocarbon chain. Other groups or atoms for fluorocarbon based compounds the oxygen atom incorporated into an ether group for anesthetics, and the chlorine atom for chlorofluorocarbons (CFCs). In a sharp contrast to true fluorocarbons, the chlorine atom produces a chlorine radical which degrades ozone. Fluorosurfactants are widely used in the production of teflon and related fluorinated polymers. They have also been used to confer hydrophobic, stain-resisting properties to fabrics.
Classes of PFCs by functional group
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.
Perfluorinated alkyl and aryl halides
- Trifluoroiodomethane, an alkylating agent
- Pentafluoroethyl iodide
- 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
Perfluoroethers and epoxides
- Pentafluorophenol, a moderately strong acid
Perfluorinated alcohols are unstable with respect to dehydrofluorination.
- Hexafluoroacetone, building block in organofluorine 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
- Pentafluorobenzoic acid, a moderately strong acid of interest in research community
- perfluorooctanoic acid (PFOA), surfactant used to make fluoropolymers such as Teflon
- perfluorononanoic acid (PFNA), surfactant in the emulsion polymerization of fluoropolymers, like PFOA.
Perfluoronitriles and isonitriles
- Trifluoromethylisocyanide, the simplest perfluorinated isonitrile.
- Trifluoromethylacetonitrile, the simplest perfluorinated nitrile
- Triflic acid, a useful strong acid
- perfluorobutanesulfonic acid (PFBS) used as a replacement for PFOS in 3M's reformulated Scotchgard.
- perfluorooctanesulfonyl fluoride (POSF), precursor to PFOS-based compounds.
- 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.
Perfluorinated aryl borates
- Na[B(C6F5)4], salt of a weakly coordinating anion.
Environmental and health concerns
Certain fluorocarbons tend to bioaccumulate, since they are extremely stable and can be stored in the bodies of both humans and animals. Examples of fluorocarbons include PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate), frequently present in water resistant textiles and sprays conferring water resistant properties to textiles. 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 are however sparse.
The fluorocarbon, PFOA and PFOS have both been subject for numerous investigations by the EU and the United States Environmental Protection Agency (EPA) regarding them being harmful to the environment.
- 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
- Murphy CD, Schaffrath C, O'Hagan D.: "Fluorinated natural products: the biosynthesis of fluoroacetate and 4-fluorothreonine in Streptomyces cattleya" Chemosphere. 2003 Jul;52(2):455-61.
- US Environmental Protection Agency. "FAQ". Perfluorooctanoic Acid (PFOA) and Fluorinated Telomers. Retrieved 11 May 2011.
- 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. Retrieved 2011-05-11.