Perfluoroethers are a class of

organofluorine compound Organofluorine chemistry describes the chemistry of the organofluorines, organic compounds that contain the carbon–fluorine bond. Organofluorine compounds find diverse applications ranging from oil and water repellents to pharmaceuticals, refri ...

containing one or more

ether In organic chemistry, ethers are a class of compounds that contain an ether group—an oxygen atom connected to two alkyl or aryl groups. They have the general formula , where R and R′ represent the alkyl or aryl groups. Ethers can again be c ...

functional group In organic chemistry, a functional group is a substituent or moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions regardless of the rest ...

. In general these compounds are structurally analogous to the related hydrocarbon ethers, except for the distinctive properties of

fluorocarbon Fluorocarbons are chemical compounds with carbon-fluorine bonds. Compounds that contain many C-F bonds often has distinctive properties, e.g., enhanced stability, volatility, and hydrophobicity. Fluorocarbons and their derivatives are commerci ...

s. The introduction of an ether function to a perfluoro-polymer chain also provides thermoplastic properties to the polymer, making thermal forming possible. This is a great technological advantage for producing a large variety of shapes (e.g., beakers, funnels, flasks for laboratory uses, etc...) and allows

extrusion Extrusion is a process used to create objects of a fixed cross-sectional profile by pushing material through a die of the desired cross-section. Its two main advantages over other manufacturing processes are its ability to create very complex c ...

of highly chemically-resistant tubing. It also confers on the polymer a translucent appearance.

Low molecular weight fluorinated ethers

Acyclic perfluoroethers are analogues of

diethylether Diethyl ether, or simply ether, is an organic compound in the ether class with the formula , sometimes abbreviated as (see Pseudoelement symbols). It is a colourless, highly volatile, sweet-smelling ("ethereal odour"), extremely flammable liq ...

, e.g. O(C₂F₅)₂, such perfluoro(2-ethoxyethane)sulfonic acid (PFEESA). More interesting and more useful are the cyclic ethers, especially, the

epoxide In organic chemistry, an epoxide is a cyclic ether () with a three-atom ring. This ring approximates an equilateral triangle, which makes it strained, and hence highly reactive, more so than other ethers. They are produced on a large scale for ...

s. Tetrafluoroethyene oxide and

hexafluoropropylene oxide Hexafluoropropylene oxide (HFPO) is an intermediate used in industrial organofluorine chemistry; specifically it is a monomer for fluoropolymers. This colourless gas is the epoxide of hexafluoropropylene, that is fluorinated analog of propylene ...

are two of the simplest cyclic perfluoroethers. These are precursors of perfluoro(methyl vinyl ether) (CF₂=CFOCF₃) and perfluoro(propyl vinyl ether), and are used as

comonomer In polymer chemistry, a comonomer refers to a polymerizable precursor to a copolymer aside from the principal monomer. In some cases, only small amounts of a comonomer are employed, in other cases substantial amounts of comonomers are used. Furthe ...

s with tetrafluoroethylene.

Polymeric perfluoroethers

Perfluoroalkoxy alkane Perfluoroalkoxy alkanes (PFA) are fluoropolymers. They are copolymers of tetrafluoroethylene (C2F4) and perfluoroethers (C2F3ORf, where Rf is a perfluorinated group such as trifluoromethyl (CF3)). The properties of these polymers are similar ...

s (PFAs) are

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 with properties similar to

polytetrafluoroethylene Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemour ...

(PTFE). Methylfluoroalkoxy (MFA) is a polytetrafluoroethylene perfluoro methylvinylether prepared with a different ratio of PTFE and MVE monomers to that used for PFA. In these materials, the ether groups are pendant from the polymer backbone.

Krytox Krytox is a registered trademark of The Chemours Company. It refers to a group of colourless synthetic lubricants (oils and greases) with a variety of applications. Invented by researchers at DuPont, Krytox oils are fluorocarbon ether polymers o ...

is a grease generated by the polymerization of hexafluoropropylene oxide. Its

chemical formula In chemistry, a chemical formula is a way of presenting information about the chemical proportions of atoms that constitute a particular chemical compound or molecule, using chemical element symbols, numbers, and sometimes also other symbols, ...

is F−(CF(CF₃)−CF₂−O)_''n''−CF₂CF₃. The ether groups are integral to the polymer chain.

Nafion Nafion is a brand name for a sulfonated tetrafluoroethylene based fluoropolymer-copolymer discovered in the late 1960s by Dr. Walther Grot of DuPont. Nafion is a brand of the Chemours company. It is the first of a class of synthetic polymers with ...

is a perfluorinated polyether with pendant

sulfonic acid In organic chemistry, sulfonic acid (or sulphonic acid) refers to a member of the class of organosulfur compounds with the general formula , where R is an organic alkyl or aryl group and the group a sulfonyl hydroxide. As a substituent, it is kn ...

groups (RSO₃H).

Precautions

At high temperatures or in a fire, perfluoroethers decompose and may release

hydrogen fluoride Hydrogen fluoride (fluorane) is an inorganic compound with the chemical formula . This colorless gas or liquid is the principal industrial source of fluorine, often as an aqueous solution called hydrofluoric acid. It is an important feedstock i ...

. Any residue must be handled using protective equipment.

References

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External links

MFA Properties
Fluoropolymers Thermoplastics Organofluorides