Octafluorocyclobutane, or perfluorocyclobutane, C<sub>4</sub>F<sub>8</sub>, is an organofluorine compound which enjoys several niche applications. Octafluorocyclobutane is a colourless gas and shipped as a liquefied gas. It is the perfluorinated analogue of cyclobutane whereby all CâÂÂH bonds are replaced with CâÂÂF bonds.
Octafluorocyclobutane is produced by the dimerization of tetrafluoroethylene and the reductive coupling of 1,2-dichloro-1,1,2,2-tetrafluoroethane.
The critical point of octafluorocyclobutane is at 115.3 ðC and 2.79 MPa.
In the production of semiconductor materials and devices, octafluorocyclobutane serves mainly as a passivation layer material in etching processes. Sometimes it is used as an etchant. It has also been investigated as a refrigerant in specialised applications, as a replacement for ozone depleting chlorofluorocarbon refrigerants. Exploiting its volatility and chemical inertness, octafluorocyclobutane may be found in some aerosolized foods. It is listed by the Codex Alimentarius under number 946 (E946 for EU). It is investigated as a possible replacement for sulfur hexafluoride as a dielectric gas.