Tetrafluoroethylene hexafluoropropene

In the mid-1980s Hoechst introduced a related material, Hostaflon TFB, a terpolymer of tetrafluoroethylene, hexafluoropropene and vinylidene fluoride. 

Many other crosslinking reactions are used in commercial applications. A variety of halogen-containing elastomers are crosslinked by heating with a basic oxide (e.g., MgO or ZnO) and a primary diamine [Labana, 1986 Schmiegel, 1979]. This includes poly(epichlorohydrin) (Sec. 7-2b-6) various co- and terpolymers of fluorinated monomers such as vinylidene fluoride, hexafluoropropene, perfluoro(methyl vinyl ether), and tetrafluoroethylene (Sec. 6-8e) and terpolymers of alkyl acrylate, acrylonitrile, and 2-chloroethyl vinyl ether (Sec. 6-8e). 

A terpene inhibitor is usually added to the monomer to prevent spontaneous polymerisation, and in its absence, the monomer will spontaneously explode at pressures above 2.7 bar. The inhibited monomer will explode if ignited [1], Explosion under thermal initiation is now held to be a disproportionation, that to tetrafluoromethane and carbon gives 3.2 kJ/g, the same energy as black powder [3]. Liquid tetrafluoroethylene, being collected in a liquid nitrogen-cooled trap open to air, formed a peroxidic polymer which exploded [2], Tetrafluoroethene is stabilised for transport or storage by admixture with considerable proportions of hexafluoropropene [4]. Explosion characteristics in long pipes at 23 bar pressure have been studied [5]. 

A proton is the weakest electrophile. For example, anhydrous HF does not add to tetrafluoroethylene at ambient temperature or to hexafluoropropene, even at 200°C [6]. Arsenic trifluoride in the presence of SbF5 (this mixture is a source of the F2As+ cation [42,43]) reacts with tetrafluoroethylene at 20 °C to form a mixture of F-(diethyl)-(4) and F-(triethyl)(5) arsines ... 

Slow decomposition of PTFE occurs above the application temperature of 260°C. However, for a noticeable decomposition to occur, temperatures above 400°C are needed. The primary decomposition products are tetrafluoroethylene (TFE) and difluorocarbon diradicals (CF2). Further products are formed by secondary reactions, depending on temperature, reaction pressure and reaction atmosphere. The typical main products are TFE, hexafluoropropene (HEP), cyclo-perfluorobutane (C-C4F8) and other fluorocarbons. Most of these substances are nontoxic, but highly toxic substances such as perfluoroisobutene or fluorophosgene are also formed under some reaction conditions. 

The photochemical reactions of tricarbonylcyclobutadieneiron compounds with tetrafluoroethylene and hexafluoropropene give rise to 1 1 addition compounds [57] to [59], the structures of which were determined spectroscopically. (45) l9F parameters are given with the... 

Tetrafluoroethylene (TFE), hexafluoropropene (HFP) and perfluoro-2-butene (PF2B) were used as monomers. 

Bening, R.C. McCarthy, T.J. Surface treatment of poly(tetrafluoroethylene-co-hexafluoropropene), introduction of alcohol functionality. Macromolecules 1990, 23, 2648-2655. 

Kavan, L. Micka, K. Kastner, J. UV-vis absorption of thin electrochemical carbon layers on poly(tetrafluoroethylene-co-hexafluoropropene). Synth. Metals 1994, 63, 147-152. 

Various copolymers of the fluorinated monomers have been prepared [243]. Copolymers of tetrafluoroethylene and hexafluoropropene have under vacuo a stability close to that of teflon (Fig. 66). Copolymers with trifluoronitroso me thane have a lower stability than PTFE (Figs. 66 and 67). The copolymer of vinylidenefluoride and hexafluoropropene is one of the most stable elastomers available at the present time (Fig. 66 and Table 12). For a typical copolymer containing 70% vinylidene fluoride, the rate of weight loss is 0.04% per min at 350°C and the activation energy is 57 to 46 kcal mole"1, according to Wright [243]. 

TETRAFLUOROETHYLENE (116-14-3) Highly reactive, thermally unstable, flammable gas (flash point <32°F/<0°C). Explodes under pressure. Able to form unstable peroxides in air. If inhibitor (usually limolene) is not present in adequate concentrations, explosive polymerization may occur above 2025 mm Hg/2.66 bar at normal temperatures. Inhibited monomer will explode on contact with iodine pentafluoride and other substances, or in elevated temperatures. Violent reaction with chloroperoxytrifluoromethane, difluoromethyl-ene dihypofluorite, dioxygen difluoride, halogens, oxidizers, oxygen, sulfur trioxide, triboron pentafluoride. Incompatible with ethylene, hexafluoropropene forms an explosive peroxide. 

Reactions of perfluorinated alkenes, such as hexafluoropropene, with fluoride ion give perfluoroalkylcarbanions which can act as nucleophiles in S Ar reactions with perfluoroheteroaromatic systems (Fig. 8.13). These reactions are another example of mirror-image chemistry and reflect well-known Friedel-Crafts reactions of hydrocarbon systems that proceed by reaction of the corresponding electrophile and carbocationic intermediates. Poly substitution processes are possible and, indeed, all five fluorine atoms may be replaced upon reaction with an excess of tetrafluoroethylene and fluoride ion. ... 

A catalytic addition of acidic alcohols or phenols to hexafluoropropene is induced by the complex Pd(PPh3)4 [110]. Catalytic activity is increased in the presence of cocatalytic l,4-bis-(diphenylphosphino)butane (dppb) (Scheme 19). The authors propose a mechanism involving external protonation of a Pd(0)-coordinated olefin and reductive elimination to the ether product, but both steps appear improbable. There is literature precedence for insertion of tetrafluoroethylene into the Pt-O bond of (dppe)PtMe(OMe) to give (dppe)PtMe(CF2CF20Me), but proto-demetallation of the resulting complex has not been reported [111, 112]. 

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