Tetrafluoro ethylene

The inability to process PTFE by conventional thermoplastics techniques has nevertheless led to an extensive search for a melt-processable polymer but with similar chemical, electrical, non-stick and low-friction properties. This has resulted in several useful materials being marketed, including tetrafluoro-ethylene-hexafluoropropylene copolymer, poly(vinylidene fluoride) (Figure 13.1(d)), and, most promisingly, the copolymer of tetrafluoroethylene and perfluoropropyl vinyl ether. Other fluorine-containing plastics include poly(vinyl fluoride) and polymers and copolymers based on CTFE. 

Chemical Reactions. Its thermal decompn in toluene gives N and hexafluoroethane plus small amts of tetrafluoromethane and tetrafluoro-ethylene (Ref 8). Photolysis of the gas gives... 

The procedure for chlorotrifluorocyclobutyl acetate is a modification of one used by Coffman, Barrick, Cramer, and Raasch for the preparation of tetrafluorocyclobutanes from tetrafluoro-ethylene. 

Reactions of Sg2+, S42"1", Se82+, Se42+ and Te42+ dications with tetrafluoro-ethylene and hexafluoropropylene usually result in formation of a mixture of products, mainly perfluoropolychalcogenides.187 189 The authors190 suggest a reaction mechanism that involves cyclic key intermediate 160. Alternatively, this transformation can be explained in terms of a free-radical mechanism (Scheme 67). 

Methylmethacrylate CH2 = C(CH3)COOCH3 a-methyl styrene CH2 = C(CH3)C6H5 Styrene CH2 = CHC6H5 Nitro ethylene CH2 = CHN02 p-nitro styrene CH2 = CHC6H4N02 Tetrafluoro ethylene F2C = CF2 Vinyl acetate CH2 = CHOCOCH2 Vinyl carbazole CH2 = CH(C12H8N)... 

As can be deduced from plant purchases, the PRC is still at the formative stage where emphasis is on producing only the most basic petrochemicals. No plants were purchased for producing dibasic acids (phthalic and maleic anhydrides, etc.) and fluro-carbon or tetrafluoro ethylene or some of the advanced engineering plastics like ABS polyacetals, polycarbonates, polyimides or any other unsaturated polyesters. Another important area of low Chinese activity is thermoplastics for space and defense applications. ... 

For instance, the Dow experimental membrane and the recently introduced Hyflon Ion E83 membrane by Solvay-Solexis are "short side chain" (SSC) fluoropolymers, which exhibit increased water uptake, significantly enhanced proton conductivity, and better stability at T > 100°C due to higher glass transition temperatures in comparison to Nafion. The membrane morphology and the basic mechanisms of proton transport are, however, similar for all PFSA ionomers mentioned. The base polymer of Nation, depicted schematically in Figure 6.3, consists of a copolymer of tetrafluoro-ethylene, forming the backbone, and randomly attached pendant side chains of perfluorinated vinyl ethers, terminated by sulfonic acid head groups. °... 

HMX 83 Teflon (Trademark of DuPont Co for tetrafluoro-ethylene polymer) 17%... 

TETRAFLUORO- ETHYLENE, INHIBITED Teflon inononter Flammable Compressed Gas 3 4 3... 

Fig. 20. Core level spectra for a series of ethylene tetrafluoro-ethylene copolymers...

Fjg. 37. Composite rate constants for interaction of Argon plasmas with ethylene tetrafluoro-ethylene copolymers obtained from analysis of the F js levels... 

Tetrafluoro ethylene handling. TFE is a difficult product to handle since trace amounts of oxygen can lead to catastrophic explosion. The pure product has been shipped in cylinders but these are very expensive. Current regulations demand... 

CF3SCFa-CF2SCF8 mw 302.17 liq, bp 80—81° was obtd when bis(trifluoromethyl) -disulfide was refluxed while tetrafluoro-ethylene gas was concurrently passed into the reaction zone, and the mixt irradiated with UV light yielding a main fraction of... 

Chemical Name poly(tetrafluoro- ethylene) poly(perfluoroalkoxy) resin poly(perfluoroethylene- propylene) poly(chloro- trifluoro- ethylene)... 

Such a process would have an intensity exponent of unity as observed. A further fact in support of the disproportionation mechanism is that the yield of CF2CI2 is largely independent of the ketone pressure at room temperature an abstraction mechanism would require a first-order dependence upon ketone pressure. While the dimer of CF2, tetrafluoro-ethylene, has never been observed in the reaction mixture, a white solid collected in the cell which was probably a polymer of CF2. While the experimental conditions are not strictly comparable, it is significant that the absorption spectrum of CF2 has been observed in the flash photolysis of 1,3-dichlorotetrafluoroacetone.39 When the temperature is raised, however, the yield of CF2C12 in normal photolysis, increases rapidly suggesting an energy of activation and this process can only be chlorine abstraction. The rate function ... 

Other halogenated copolymers, in which an isomorphous replacement is observed, were studied by Leshchenko, Karpov, and Kargin (19, 20) and later by Natta, Allegra, and Bassi (21). The former authors show that copolymers obtained from vinylidene fluoride and tetrafluoro ethylene are crystalline and show a tendency to altemance between the two types of monomer units (19). The same authors studied the vinylidene fluoride/hexafluoro propylene and the vinylidene fluoride/ trifluorochloro ethylene copolymer systems. In the former case crystallinity is observed up to contents of about 10% of the second component, the crystal structure being that of polyvinylidene fluoride. In the latter case crystallinity disappears for vinylidene fluoride contents in the order of 16%, the observed structure being that of polytrifluorochloro ethylene (20). 

The compound (dppe)PtMe(OMe),256 which is prepared by a metathesis reaction involving NaOMe and (dppe)PtMe(Cl) in a mixed benzene/methanol solvent system (dppe = bis(l,2-di-phenylphosphino)ethane), does not react with ethylene or pentene but does react with activated alkenes such as acrylonitrile, methylacrylate and fluoroalkenes. The reaction involving tetrafluoro-ethylene has been shown to give (dppe)PtMe(CF2CF2OMe), providing the first example of an alkene insertion into an M—OR bond.256 Interestingly, no insertion into the Pt—Me bond was observed. 

The isotope fluorine-18 has a half-life of 110 min if the interval between its preparation and use can be kept short, it might be useful in a number of connections. It has been suggested (48) that 18F-labelled poly-tetrafluoro-ethylene and other fluoro-polymers might be used to determine their very low solubilities, and to study their frictional properties by methods similar to those already used in examination of the lubricating properties of other materials. 

A sensor for organic chloride-containing compounds was constructed by immobilization of luminol or tris (2,2 bipyridyl) ruthenium (III) between a PMT and a poly (tetrafluoro) ethylene (PTFE) membrane [15], through which a stream of air was sampled by diffusion. A heated Pt filament incorporated in the gas line leading to the CL cell was used to oxidize the analytes prior to diffusion across the PTFE membrane. Detection limits for CC14, CHC13, and CH2C12 were 1.2-4 ppm. A similar device could also be used for the determination of hydrazine and its monomethyl and dimethyl derivatives or NH3 vapor. The detection limit for hydrazine was only 0.42 ppb [16]. 

Recently, a process involving chemical recycling of PTFE using fluidized bed has been developed and patented.3 5 The optimum temperature is in the range of 545 to 600°C (1013 to 1112°F) and the main decomposition products are tetrafluoro-ethylene (TEE), hexafluoropropene (HFP), and cyclo-perfluorobutane (c-C4F8). The most important advantages of this process are that the monomers produced can be purified before repolymerization, which allows production of a more valuable product, and that the process is continuous.1... 

It is interesting to note here that the ring-closed isomer of the 2-cyanoallyl anion, i.e. the (M — H) ion of cyanocyclopropane, reacts with tetrafluoro-ethylene with expulsion of two molecules of hydrogen fluoride as well, albeit to a minor extent. Most of the corresponding collision complexes, however, appear to eliminate a molecule of ethylene, for which (56) represents the most satisfactory mechanism so far presented (Dawson and Nibbering, 1980). 

Aromatic primary amines are not only binucleophiles at the amino group, but they also exhibit the properties of C,N-binucleophiles. Their reactions with internal perfluoroolefins lead to quinoline derivatives (98JFC(88)169, 94JCS(CC)134, 98T4949). Thus the reaction of aniline with 2//-heptafluorobut-2-ene yields phenyl(2-trifluoromethylquinolin-4-yl) amine (00ZOR109) when the reaction is carried out with the tetrafluoro-ethylene trimer, it leads to 2-trifluoromethyl-3-(l-N-phenylimino-2,2,2-trifluoroethyl)-4-(N-phenylamino)quinoline (98JFC(88)169). 

It is difficult to achieve a gas-tight seal to the anode current connections, which must also be electrically insulated against the cover of the electrolyzer, to which the cathodes are attached. Formerly, fused calcium fluoride was used as sealing material. This is, however, brittle and sometimes even porous recently sintered corundum has been used and for the external packing teflone (polymerized tetrafluoro-ethylene), buna, and polyvinylchloride. 

Tetra fluoro benzyl alcohol transfluthrin Tetrafluoro ethylene flupropanate, tetraconazole... 

McCrum, N. G. A study of internal friction of copolymers of tetrafluoro-ethylene and hexafluoroethylene. Makromol. Chem. 34, 50—66 (1959). 

POLYPROPYLENE zPOLYETHYLENE H.D. POLY(TETRAFLUORO ETHYLENE) (Teflon )... 

If all the hydrogen atoms in ethylene are replaced by fluorine atoms, tetrafluoro ethylene results. Tetrafluoroethylene is polymerized to form polytetrafluoro ethylene. Polytetrafluoroethylene, known as teflon, is used in the production of nonstick cooking ware. 

---