Fluorocarbon

Compounds that contain many C-F bonds often have distinctive properties, e.g., enhanced[clarification needed] stability, volatility, and hydrophobicity.

[4] Its strength is a result of the electronegativity of fluorine imparting partial ionic character through partial charges on the carbon and fluorine atoms, which shorten and strengthen the bond (compared to carbon-hydrogen bonds) through favorable covalent interactions.

As the high electronegativity of fluorine reduces the polarizability of the atom,[1] fluorocarbons are only weakly susceptible to the fleeting dipoles that form the basis of the London dispersion force.

As a result, fluorocarbons have low intermolecular attractive forces and are lipophobic in addition to being hydrophobic and non-polar.

It has been suggested that an atmosphere containing a significant percentage of perfluorocarbons on a space station or similar would prevent fires altogether.

[12] The table shows values for the mole fraction, x1, of nitrogen dissolved, calculated from the Blood–gas partition coefficient, at 298.15 K (25 °C), 0.101325 MPa.

Electrochemical fluorination (ECF) (also known as the Simons' process) involves electrolysis of a substrate dissolved in hydrogen fluoride.

To make perfluorohexane, trihexylamine is used, for example: The perfluorinated amine will also be produced: Fluoroalkanes are generally inert and non-toxic.

[21] Low-boiling perfluoroalkanes are potent greenhouse gases, in part due to their very long atmospheric lifetime, and their use is covered by the Kyoto Protocol.

[citation needed][22] The global warming potential (compared to that of carbon dioxide) of many gases can be found in the IPCC 5th assessment report,[23] with an extract below for a few perfluoroalkanes.

The aluminium smelting industry has been a major source of atmospheric perfluorocarbons (tetrafluoromethane and hexafluoroethane especially), produced as by-product of the electrolysis process.

[1] Unsaturated fluorocarbons have a driving force towards sp3 hybridization due to the electronegative fluorine atoms seeking a greater share of bonding electrons with reduced s character in orbitals.

Perfluoroaromatic compounds can be manufactured via the Fowler process, like fluoroalkanes, but the conditions must be adjusted to prevent full fluorination.

A third route is defluorination of the fluoroalkane; for example, octafluorotoluene can be made from perfluoromethylcyclohexane by heating to 500 °C with a nickel or iron catalyst.

Beaker with two layers of liquid, goldfish and crab in top, coin sunk in the bottom
Immiscible layers of colored water (top) and much denser perfluoroheptane (bottom) in a beaker; a goldfish and crab cannot penetrate the boundary; coins rest at the bottom.
Atmospheric concentration of PFC-14 and PFC-116 compared to similar man-made halogenated gases between years 1978 and 2015 (right graph). Note the logarithmic scale.