Tetrafluoroethylene reaction

The syntheses of cation salts of the monocyclic fluoroaromatic compounds and of octafluoronaphthalene have been described elsewhere (1-5). Manipulations of air-or moisture-sensitive materials were carried out in a Vacuum Atmospheres Dri-Lab or in a stainless steel vacuum line fitted with a Teflon FEP[poly(tetrafluoroethylene)] reaction vessel (Chemplast) or a fused silica reaction vessel. 

The reactions with IF are more amenable to control giving good yields of identifiable products and lower losses from oxidative fragmentation. The reaction of IF and iodine with tetrafluoroethylene produces the telomer perfluoroethyl iodide [354-64-3] ia yields that exceed 98% based on... 

Reactions with Organic Compounds. Tetrafluoroethylene and OF2 react spontaneously to form C2F and COF2. Ethylene and OF2 may react explosively, but under controlled conditions monofluoroethane and 1,2-difluoroethane can be recovered (33). Benzene is oxidized to quinone and hydroquinone by OF2. Methanol and ethanol are oxidized at room temperature (4). Organic amines are extensively degraded by OF2 at room temperature, but primary aHphatic amines in a fluorocarbon solvent at —42°C are smoothly oxidized to the corresponding nitroso compounds (34). 

Tetrafluoroethylene Oxide TFEO has only been prepared by a process employing oxygen or ozone because of its extreme reactivity with ionic reagents. This reactivity may best be illustrated by its low temperature reaction with the weak nucleophile, dimethyl ether, to give either of two products (47) (eq. 10). 

Fluorinated ether-containing dicarboxyhc acids have been prepared by direct fluorination of the corresponding hydrocarbon (17), photooxidation of tetrafluoroethylene, or by fluoride ion-cataly2ed reaction of a diacid fluoride such as oxalyl or tetrafluorosuccinyl fluorides with hexafluoropropylene oxide (46,47). Equation 8 shows the reaction of oxalyl fluoride with HEPO. A difunctional ether-containing acid fluoride derived from HEPO contains regular repeat units of perfluoroisopropoxy group and is terminated by two alpha-branched carboxylates. 

Properties. Tetrafluoroethylene (mol wt 100.02) is a colorless, tasteless, odorless, nontoxic gas (Table 1). It is stored as a Hquid vapor pressure at —20° C = 1 MPa (9.9 atm). It is usually polymerized above its critical temperature and below its critical pressure. The polymerization reaction is highly exothermic. 

Tetrafluoroethylene undergoes addition reactions typical of an olefin. It bums in air to form carbon tetrafluoride, carbonyl fluoride, and carbon dioxide (24). Under controlled conditions, oxygenation produces an epoxide (25) or an explosive polymeric peroxide (24). Trifluorovinyl ethers,... 

Preparation. The preparation of tetrafluoroethylene has been described previously. Perfluorovinyl ethers (4—7) are prepared by the following steps. Hexafluoropropylene [116-15-4] (HEP) is oxidized to an epoxide HEPO [428-59-1] (5) which, on reaction with perfluorinated acyl fluorides, gives an alkoxyacyl fluoride. 

Difluoroaminofluorodiazirine (225) extrudes nitrogen at only 75 °C. Intramolecular stabilization gives trifluoromethylenimine (226) added tetrafluoroethylene is cyclopropa-nated. This type of dichotomy is not often found in carbene chemistry alkylcarbenes undergo intramolecular stabilization as a rule, whereas intermolecular stabilization is observed exclusively with alkoxycarbonylcarbenes and with difluorocarbene. In the latter case CF2 attacks its precursor when no other reaction partner is present. 

Chloro-2,2,3-trifluoropropionic acid has been prepared by permanganate oxidation of 3-chloro-2,2,3-trifluoropropanol which is one of the telomerization products of chlorotrifluoroethylene with methanol. The present procedure is a modification of one reported earlier and is undoubtedly the method of choice for making propionic acids containing 2 fluorine atoms, i.e., 2,2,3,3-tetrafluoropropionic acid, 3,3-dichloro-2,2-difluoropropionic acid, and 3-bromo-2,2,3-trifluoropropionic acid. When preparing 2,2,3,3-tetrafluoropropionic acid from tetrafluoroethylene, it is desirable to use an additional 50 ml. of acetonitrile and externally applied heat to initiate the reaction. 

Perfluoro-2 (1 ethyl 1 methylpropyl)-3-methyl-l-pentene, the major hex-amer of tetrafluoroethylene, reacts with sodium methoxide to yield an ester, whereas a stable crowded ketene is formed by reaction with sodium hydroxide [2d] (equation 23)... 

Copyrolysis of 1,1-diehloroperfluoroindane and chlorodifluoromethane or tetrafluoroethylene gives 1-perfluoromethyleneindane as the major product and three minor products [3] (equation 2) Insertion of difluorocatbene into the benzylic carbon-chlorine bond and subsequent loss of a chlonne molecule is observed in the copyrolysis of chlorodifluoromethane and pentafluorobenzotnchlonde to give a-chloroperfluorostyrene as the major product. Aromatic carbon-chlorine bonds are unreactive to the difluorocarbene in this reaction [4] (equation 3). 

A -Halogenated compounds such as iV-chlorotnfluoroacetamide, A -chloro-imidosulfuryl fluonde and N N dichlorotnfluoromethylamine add across C=C bonds to form saturated amides [14] tmidosulfury I fluorides [15] and amines [16], respectively Allylic halogenation also occurs with the use of A-bromo- or A-chIo roperfluoroamides The primary amine A,A-dichlorotrifluororaethylamine selectively affords 11 or 2 1 adducts with either tetrafluoroethylene or chlorotrifluoroethylene [16] (equation 7) The reaction mechanism is believed to involve thermal free radicals, with control achieved principally by reaction temperature The 1 1 adduct is formed even in the presence of a large excess of olefin... 

These types of reactions have been used extensively to pTspaicJluorotelomers For example, Zonyl products, manufactured by E I du Pont de Nemours Co, Inc, are based on materials prepared from perfluoroethyl iodide and tetrafluoroethylene [2] (equation 1)... 

The synthesis of 2-chloro-2,3,3-trifluorocyclobutyl acetate illustrates a general method of preparing cyclobutanes by heating chlorotrifluoroethylene, tetrafluoroethylene, and other highly fluorinated ethylenes with alkenes. The reaction has recently been reviewed.11 Chlorotrifluoroethylene has been shown to form cyclobutanes in this way with acrylonitrile,6 vinylidene chloride,3 phenylacetylene,7 and methyl propiolate.3 A far greater number of cyclobutanes have been prepared from tetrafluoroethylene and alkenes 4,11 when tetrafluoroethylene is used, care must be exercised because of the danger of explosion. The fluorinated cyclobutanes can be converted to a variety of cyclobutanes, cyclobutenes, and butadienes. 

Temperature dependence (related to the temperature dependence of the conformational structure and the morphology of polymers) of the radiation effect on various fluoropolymers e.g., poly (tetrafluoroethylene-co-hexafluoropropylene), poly(tetrafluoroethylene-co-perfluoroalkylvinylether), and poly(tetrafluoroethylene-co-ethylene) copolymers has been reported by Tabata [419]. Hill et al. [420] have investigated the effect of environment and temperature on the radiolysis of FEP. While the irradiation is carried out at temperatures above the glass transition temperature of FEP, cross-linking reactions predominate over chain scission or degradation. Forsythe et al. [421]... 

SCHEME 31. S (a) Oxidation, dehydrofluorination and crosslinking reactions as a result of EB irradiation of poly (vinylidenefluoride-co-hexafluoropropylene-co-tetrafluoroethylene). (b) Chain scission reactions as a result of EB irradiation of poly (vinylidenefluoride-co-hexafluoropropylene-co-tetrafluoroethylene). 

In solution polymerization, monomers mix and react while dissolved in a suitable solvent or a liquid monomer under high pressure (as in the case of the manufacture of polypropylene). The solvent dilutes the monomers which helps control the polymerization rate through concentration effects. The solvent also acts as a heat sink and heat transfer agent which helps cool the locale in which polymerization occurs. A drawback to solution processes is that the solvent can sometimes be incorporated into the growing chain if it participates in a chain transfer reaction. Polymer engineers optimize the solvent to avoid this effect. An example of a polymer made via solution polymerization is poly(tetrafluoroethylene), which is better knoivn by its trade name Teflon . This commonly used commercial polymer utilizes water as the solvent during the polymerization process,... 

Accidental contamination of a tetrafluoroethylene gas supply system with iodine pentafluoride caused a violent explosion in the cylinders. Exothermic reaction of the limonene inhibitor with the contaminant present in the gas cylinders may have depleted the inhibitor and initiated explosive polymerisation. 

Although tetrafluoroethylene and other 1,1-difluoroalkenes readily undergo thermally-induced [2 + 2] dimerization, perfluoromethylenecyclopropane (105) does not dimerize on heating at 150°C for 24 h [28]. On the other hand, it readily undergoes [4 + 2] cycloaddition reactions (Table 10) [29]. 

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