Octafluorocyclobutane, or perfluorocyclobutane, C
4F
8, is an
organofluorine compound
Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, ...
which enjoys several niche applications. Octafluorocyclobutane is a colourless gas and shipped as a liquefied gas. It is the perfluorinated analogue of
cyclobutane
Cyclobutane is a cycloalkane and organic compound with the formula (CH2)4. Cyclobutane is a colourless gas and is commercially available as a liquefied gas. Derivatives of cyclobutane are called cyclobutanes. Cyclobutane itself is of no commerc ...
whereby all C–H bonds are replaced with
C–F bonds.
Production
Octafluorocyclobutane is produced by the dimerization of
tetrafluoroethylene
Tetrafluoroethylene (TFE) is a fluorocarbon with the chemical formula . It is a colorless gas. Its structure is . It is used primarily in the industrial preparation of fluoropolymers. It is the simplest perfluorinated alkene.
It was first repor ...
and the reductive coupling of
1,2-dichloro-1,1,2,2-tetrafluoroethane.
[.]
Applications
In the production of
semiconductor
A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping level ...
materials and devices, octafluorocyclobutane serves as a
etchant.
[{{cite journal , doi=10.1116/1.4843575 , title=Fluorocarbon assisted atomic layer etching of SiO2 using cyclic Ar/C4F8 plasma , date=2014 , last1=Metzler , first1=Dominik , last2=Bruce , first2=Robert L. , last3=Engelmann , first3=Sebastian , last4=Joseph , first4=Eric A. , last5=Oehrlein , first5=Gottlieb S. , journal=Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films , volume=32 , issue=2 , page=020603 , bibcode=2014JVSTA..32b0603M ] It has also been investigated as a
refrigerant
A refrigerant is a working fluid used in the cooling, heating, or reverse cooling/heating cycles of air conditioning systems and heat pumps, where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are ...
in specialised applications, as a replacement for
ozone depleting chlorofluorocarbon
Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly Halogenation, halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F). They are produced as volatility (chemistry), volat ...
refrigerants. Exploiting its volatility and chemical inertness, octafluorocyclobutane may be found in some aerosolized foods. It is listed by the
Codex Alimentarius
The is a collection of internationally recognized standards, codes of practice, guidelines, and other recommendations published by the Food and Agriculture Organization (FAO) and World Health Organization (WHO) of the United Nations relating to f ...
under number 946 (E946 for EU). It is investigated as a possible replacement for
sulfur hexafluoride
Sulfur hexafluoride or sulphur hexafluoride ( British spelling) is an inorganic compound with the formula SF6. It is a colorless, odorless, non-flammable, and non-toxic gas. has an octahedral geometry, consisting of six fluorine atoms attache ...
as a
dielectric gas.
Gallery
File:PFC-c-318 mm.png, PFC-318 measured by the Advanced Global Atmospheric Gases Experiment
AGAGE
in the lower atmosphere (troposphere
The troposphere is the lowest layer of the atmosphere of Earth. It contains 80% of the total mass of the Atmosphere, planetary atmosphere and 99% of the total mass of water vapor and aerosols, and is where most weather phenomena occur. From the ...
) at stations around the world. Abundances are given as pollution free monthly mean mole fractions in parts-per-trillion.
References
Appendix
Its
critical point is at 115.3 °C and 2.79 MPa.
Fluorocarbons
Aerosol propellants
Refrigerants
Dielectric gases
Cyclobutanes