Perfluorocarbon

Perfluorohexane, a fluorocarbon

Perfluorocarbons (PFCs) are fluorocarbons, compounds derived from hydrocarbons by replacement of hydrogen atoms by fluorine atoms. Perfluorocarbons are made up of carbon and fluorine atoms only. ^[1]

Perfluorocarbons may be fully saturated, i.e., perfluoroalkanes, for example octafluoropropane, perfluorohexane and perfluorodecalin. Perfluorocarbon is sometimes used to refer specifically to perfluoroalkanes. They may contain double bonds (perfluoroalkenes, such as Tetrafluoroethylene, hexafluoropropylene and perfluoroisobutene), triple bonds (perfluoroalkynes) or aromatic rings (perfluoraromatics, such as hexafluorobenzene). The term "perfluorocarbon" may be used to refer to perfluoroalkanes only.

Perfluorocarbon derivatives are perfluorocarbons with some functional group attached, for example perfluorooctanesulfonic acid. Perfluorocarbon derivatives can be very different from perfluorocarbons in their properties, applications and toxicity. The term Perfluorinated compounds or perfluorochemical (also abbreviated to PFC) may indicate perfluorcarbons, but is often used to include perfluorocarbon derivatives.

Properties

Perfluorocarbons tend to be clear, colorless liquids or gases, with a high density and refractive index.

Perfluoroalkanes

Perfluoroalkanes are characterized by very lower intermolecular forces. They are chemically inert, thermally stable and non-toxic. They have low viscosity and surface tension, and high volatility (compared with the corresponding hydrocarbon). They are immiscible with most common solvents, but have a relatively high solubility for gases.

Unsaturated perfluorocarbons

The double or triple bond or aromatic system in an unsaturated perfluorocarbon allows some degree of intermolecular bonding, and also offers a point of reactivity. They will undergo a range of chemical reactions, and many are toxic (perfluoro-iso-butylene is noted as especially toxic). Unsaturated perfluorocarbons tend to be miscible with common solvent. Perfluoroalkenes and perfluoroalynes generally undergo addition reactions with nucleophiles (in contrast to hydrocarbon alkenes, which react with electrophiles).^[2]

See also

• Fluorocarbon
• Perfluoroalkane
• Fluoropolymer

References