Perfluorooctanoic acid
Perfluorooctanoic acid (PFOA; conjugate base perfluorooctanoate; also known colloquially as C8, for its 8-carbon chain structure) 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.
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| Preferred IUPAC name
Pentadecafluorooctanoic acid | |
| Other names
Perfluorooctanoic acid, PFOA, C8, Perfluorooctanoate, PFO, Perfluorocaprylic acid, C8-PFCA, FC-143, F-n-octanoic acid | |
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| ECHA InfoCard | 100.005.817 |
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CompTox Dashboard (EPA) |
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| Properties | |
| C8HF15O2 | |
| Molar mass | 414.07 g/mol |
| Appearance | White solid |
| Density | 1.8 g/cm3 |
| Melting point | 40 to 50 °C (104 to 122 °F; 313 to 323 K) |
| Boiling point | 189 to 192 °C (372 to 378 °F; 462 to 465 K) |
| Soluble, 9.5 g/L (PFO) | |
| Solubility in other solvents | Polar organic solvents |
| Acidity (pKa) | ~0 |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards |
Strong acid, known carcinogen, persistent organic pollutant |
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| Danger | |
| H302, H318, H332, H351, H360, H362, H372 | |
| P201, P202, P260, P261, P263, P264, P270, P271, P280, P281, P301+P312, P304+P312, P304+P340, P305+P351+P338, P308+P313, P310, P312, P314, P330, P405, P501 | |
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Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references | |
PFOA is one of many synthetic organofluorine compounds collectively known as per- and polyfluoroalkyl substances (PFASs).
PFOA is used in several industrial applications, including carpeting, upholstery, apparel, floor wax, textiles, fire fighting foam and sealants. PFOA serves as a surfactant in the emulsion polymerization of fluoropolymers and as a building block for the synthesis of perfluoroalkyl-substituted compounds, polymers, and polymeric materials. PFOA has been manufactured since the 1940s in industrial quantities. It is also formed by the degradation of precursors such as some fluorotelomers. PFOA is used as a surfactant because it can lower the surface tension of water more than hydrocarbon surfactants while having exceptional stability due to having perfluoroalkyl tail group. The stability of PFOA is desired industrially but is a cause of concern environmentally.
The primary manufacturer of perfluorooctanesulfonic acid (PFOS), the 3M Company (known as Minnesota Mining and Manufacturing Company from 1902 to 2002), began a production phase-out in 2002 in response to concerns expressed by the United States Environmental Protection Agency (EPA).: 2 Eight other companies agreed to gradually phase out the manufacturing of the chemical by 2015.: 3
By 2014, EPA had listed PFOA and perfluorooctanesulfonates (salts of perfluorooctanesulfonic acid, PFOS) as emergent contaminants:
PFOA and PFOS are extremely persistent in the environment and resistant to typical environmental degradation processes. [They] are widely distributed across the higher trophic levels and are found in soil, air and groundwater at sites across the United States. The toxicity, mobility and bioaccumulation potential of PFOS and PFOA pose potential adverse effects for the environment and human health.: 1