Hexafluoropropylene oxide (HFPO) is an intermediate used in industrial

organofluorine chemistry Organofluorine chemistry describes the chemistry of organofluorine compounds, organic compounds that contain a carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from Lipophobicity, oil and hydrophobe, water repell ...

; specifically it is a monomer for

fluoropolymer A fluoropolymer is a fluorocarbon-based polymer with multiple carbon–fluorine bonds. It is characterized by a high resistance to solvents, acids, and bases. The best known fluoropolymer is polytetrafluoroethylene under the brand name "Teflon, ...

s. This colourless gas is the

epoxide In organic chemistry, an epoxide is a cyclic ether, where the ether forms a three-atom ring: two atoms of carbon and one atom of oxygen. This triangular structure has substantial ring strain, making epoxides highly reactive, more so than other ...

hexafluoropropylene Hexafluoropropylene is the fluoroalkene with the formula CF3CF=CF2. It is the perfluorocarbon counterpart to the hydrocarbon propylene. It is mainly used to produce copolymers with tetrafluoroethylene. Hexafluoropropylene is used as a chemical i ...

, which is a fluorinated analog of

propylene oxide Propylene oxide is an epoxide with the molecular formula C3H6O. This colourless volatile liquid with an odour similar to ether, is produced on a large scale industrially. Its major application is its use for the production of polyether polyols f ...

, HFPO is produced by

Chemours The Chemours Company (, ) is an American chemical industry, chemical company that was founded in July 2015 as a Corporate spin-off, spin-off from DuPont. It has its corporate headquarters in Wilmington, Delaware, United States. Chemours is the m ...

and 3M and as a precursor to the lubricant Krytox and related materials. It is generated by oxidation of perfluoropropylene, e.g. with oxygen as well as other oxidants.

Reactivity

Fluoride catalyzes the formation of perfluorinated polyethers such as Krytox. The initial step entails

nucleophilic attack In chemistry, a nucleophile is a chemical species that forms bonds by donating an electron pair. All molecules and ions with a free pair of electrons or at least one pi bond can act as nucleophiles. Because nucleophiles donate electrons, they a ...

at the middle carbon to give the perfluoropropoxide anion, which in turn attacks another monomer. This process generates a polymer terminated by an acyl fluoride, which is hydrolyzed to the

carboxylic acid In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an Substituent, R-group. The general formula of a carboxylic acid is often written as or , sometimes as with R referring to an organyl ...

which is decarboxylated with fluorine. The net polymerization reaction can be represented as: : Upon heating above 150 °C, HFPO decomposes to trifluoroacetyl fluoride and

difluorocarbene Difluorocarbene is the chemical compound with formula CF2. It has a short half-life, 0.5 and 20 ms, in solution and in the gas phase, respectively.Douglas A Jean Osteraas "Difluorocarbene Modification of Polymer and Fiber Surfaces," ''Journal ...

: : The epoxide 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 ...

is even more unstable with respect to trifluoroacetyl fluoride. In the presence of

Lewis acid A Lewis acid (named for the American physical chemist Gilbert N. Lewis) is a chemical species that contains an empty orbital which is capable of accepting an electron pair from a Lewis base to form a Lewis adduct. A Lewis base, then, is any ...

s the compound rearranges to hexafluoroacetone, another important chemical intermediate. This rearrangement can be of concern during storage as the rearrangement be catalyzed by the material of the storage cylinder's walls and leads to unwanted formation of HFA during storage. As a result of this, 3M recommends using all HFPO shipped in carbon-steel containers within 90 days of shipping. Methanolysis affords methyl trifluoropyruvate, a reagent useful in organic synthesis: :{{chem2, CF3CFCF2O + 2 MeOH → CF3C(O)CO2Me + MeF + 2 HF

References

External links

HFPO bulletin from ChemoursDyneon HFPO from 3M
Trifluoromethyl compounds Epoxides Perfluorinated compounds Monomers