116-14-3 Tetrafluoroethene

Tetrafluoroethene F2C = CF2 (-CF2-CF2-) (Teflon) Nonstick coating for cooking utensils bearings gaskets and fittings... 

Teflon IS made in a similar way by free radical polymerization of tetrafluoroethene... 

Many perfluoroaUphatic ethers and tertiary amines have been prepared by electrochemical fluorination (1 6), direct fluorination using elemental fluorine (7—9), or, in a few cases, by fluorination using cobalt trifluoride (10). Examples of lower molecular weight materials are shown in Table 1. In addition to these, there are three commercial classes of perfluoropolyethers prepared by anionic polymerization of hexafluoropropene oxide [428-59-1] (11,12), photooxidation of hexafluoropropene [116-15-4] or tetrafluoroethene [116-14-3] (13,14), or by anionic ring-opening polymeriza tion of tetrafluorooxetane [765-63-9] followed by direct fluorination (15). 

The final products for the photooxidation of tetrafluoroethene have the following stmcture where the ratio m/n is between 0.6—1.5 and is typically about 0.8 (14). The average molecular weight of these polyethers is between ca 1,000 and 40,000. 

Tetrafluoroethene hexamer reacts with ammonia to give a nitrile. The reaction occurs probably by initial formation of a very reactive cyanoolefin [95] (equation 81). 

The known chemistry of the bisftrifluoromethyOnitroxyl [3i, 34] includes additions to both olefins [75, 36 37] and fluoroolefins [iaddition products with chlorotnfluoroethene or tetrafluoroethene [39] The nitroso denvative, (Cp3)3NONO, reacts with a liimted set of halogenated olefins to add the (CF3)2NO and NO moieties [40]... 

Sketch three repeating units of the polymer formed from (a) tetrafluoroethene (b) phenylethene (c) CHiCH=GHGHv... 

Poly(tetrafluoroethene) Non-stick ovenware, chemicals for seals and burette taps... 

Tetrafluoroethene polymerizes to form the slippery polymer that is commonly known as Teflon . Teflon M is used as a non-stick coating in frying pans, among other uses. Classify the following polymerization reaction, and name the product. (The letter n indicates that many monomers are involved in the reaction.)... 

The monomer reactant of this polymerization reaction contains a double bond. The product polymer has no double bond, so an addition reaction must have occurred. Thus, this reaction is an addition polymerization reaction. Since the monomer s name is tetrafluoroethene, the product s name is polytetrafluoroethene. 

Teflon is manufaetured by heating tetrafluoroethene with a free radical or persulphate catalyst at high pressures. It Is ehemleally inert and resistant to attack by corrosive reagents. It Is used in making oil seals and gaskets and also used for non - stick surface coated utensils. 

Dichlorodithionitronium cation, ClSNSCl, adds to alkynes forming cations (87) in 97% yield probably via the intermediate l,3-dichloro-l,3,2-dithiazolinium cations (90) <90CJC852>. Cation Cl2S2N is less reactive than cation S2N it does not add to hexafluoro-2-butyne or MeCN. However, it is more accessible and preferable for preparative purposes. It adds also to alkenes quantitatively giving stable l,3-dichloro-l,3,2-dithiazolinium cations (91) which in turn can add to excess of alkene with loss of chlorine affording bicyclic cations (89) <90CJC852>. Tetrafluoroethene does not react evidently on electronic grounds, tetramethylethene fails to form expected adducts presumably for steric reasons. 

The trifluorovinyl analog 38 (Hal = F) could be obtained by reaction of carbazol-9-ylpotassium with tetrafluoroethene in tetrahydrofuran solution at room temperature (cf. ref. 86). A complex mixture of products resulted from irradiation of carbazole in the presence of carbon tetrachloride the inclusion of ethanol or water led to different products resulting from later interaction with these nucleophiles. In the absence of nucleophiles and in 3-methylpentane solution, 9-trichlorovinylcarbazole (38 Hal = Cl) was the main product. ... 

The mixed dimerization of polyhalogenated alkenes with both activated and nonactivated alkcncs has been well documented (see Houben-Weyl, Vol. 4/4, p 206) and continues to represent a convenient preparative method for polyhalogenated cyclobutanes. Of the polyhalogenated alkenes, the fluorinated ethenes are the most reactive towards [2 + 2] cycloadditions. The method is, however, limited by the nonstereoselectivity due largely to the formation of 1,4-diradical intermediates and the requirement of high temperatures. The observation of stereochemical equilibration is seen in the cycloaddition products of tetrafluoroethene (1) with (island (Z)-but-2-ene and (Z)-l,2-[2H2]ethene where mixtures of stereoisomeric cyclobutanes are obtained.19-20... 

The [2 + 2] cycloaddition of tetrafluoroethene (1) with silyl- and siloxy-substituted alkenes (9) can be a preparatively useful reaction.21... 

Tetraphcnylbutatriene (36) and tetra- er -butylhexapentaene (38) also form cycloadducts with tetrafluoroethene at the central double bond.26... 

It was shown later that this reaction, and also pyrolyses of tetrafluoroethene (3) and of PTFE, can be adapted36 to give hexafluoropropene and also perfluoro(2-methylpropene), the key stage being formation of difluorocarbene. 

Ruff and Bretschneider obtained tetrafluoroethene (then a new compound) and hexa-fluoroethane by passing carbon tetrafluoride through an arc between carbon electrodes. 

Unsaturated fluorinated compounds are fundamentally different from those of hydrocarbon chemistry. Whereas conventional alkenes are electron rich at the double bond, fluoroal-kenes suffer from a deficiency of electrons due to the negative inductive effect. Therefore, fluoroalkenes react smoothly in a very typical way with oxygen, sulfur, nitrogen and carbon nucleophiles.31 Usually, the reaction path of the addition or addition-elimination reaction goes through an intermediate carbanion. The reaction conditions decide whether the product is saturated or unsaturated and if vinylic or allylic substitution is required. Highly branched fluoroalkenes, obtained from the fluoride-initiated ionic oligomerization of tetrafluoroethene or hexafluoropropene, are different and more complex in their reactions and reactivities. 

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