Vinyl fluoride, reaction

Af-vinyl carbazole, reaction type 212 vinyl chloride, reaction type 212 vinyl ester, reaction type 212 vinyl ether, reaction type 212 vinyl fluoride, reaction type 212 vinylidene, reaction type 212 chloride At-vinylpyrrolidone, reaction type 212 virus, tobacco necrosis, crystal structure 166... 

Another use of hydrogen fluoride, although not in halogen exchange, is the reaction with ethylenes or acetylenes to form the addition products, 1,1-difluoroethane [75-37-6] and vinyl fluoride [75-02-5]-. 

Reaction conditions must be controlled since HF is also an excellent polymerization catalyst. Controlled reaction conditions can alternatively lead to vinyl fluoride or to HFC-152a (CH2CHF2). The latter can be thermally cracked to form vinyl fluoride. 

In 1954 the surface fluorination of polyethylene sheets by using a soHd CO2 cooled heat sink was patented (44). Later patents covered the fluorination of PVC (45) and polyethylene bottles (46). Studies of surface fluorination of polymer films have been reported (47). The fluorination of polyethylene powder was described (48) as a fiery intense reaction, which was finally controlled by dilution with an inert gas at reduced pressures. Direct fluorination of polymers was achieved in 1970 (8,49). More recently, surface fluorinations of poly(vinyl fluoride), polycarbonates, polystyrene, and poly(methyl methacrylate), and the surface fluorination of containers have been described (50,51). Partially fluorinated poly(ethylene terephthalate) and polyamides such as nylon have excellent soil release properties as well as high wettabiUty (52,53). The most advanced direct fluorination technology in the area of single-compound synthesis and synthesis of high performance fluids is currently practiced by 3M Co. of St. Paul, Minnesota, and by Exfluor Research Corp. of Austin, Texas. 

Vlayl fluoride [75-02-5] (VF) (fluoroethene) is a colorless gas at ambient conditions. It was first prepared by reaction of l,l-difluoro-2-bromoethane [359-07-9] with ziac (1). Most approaches to vinyl fluoride synthesis have employed reactions of acetylene [74-86-2] with hydrogen fluoride (HF) either directly (2—5) or utilizing catalysts (3,6—10). Other routes have iavolved ethylene [74-85-1] and HF (11), pyrolysis of 1,1-difluoroethane [624-72-6] (12,13) and fluorochloroethanes (14—18), reaction of 1,1-difluoroethane with acetylene (19,20), and halogen exchange of vinyl chloride [75-01-4] with HF (21—23). Physical properties of vinyl fluoride are given ia Table 1. 

Table 2). Either vinyl fluoride or 1,1-difluoroethane can be obtained ai the major product from liquid- or vapor-phase reactions. 

Convenient syntheses of vinyl fluorides are of synthetic interest, fhe conjugate base of fluoromethyl phenyl sulfone reacts with carbonyl compounds to provide P-tluoro alcohols, which are used to prepare terminal vinyl fluorides [25] (equation 23) (Table 9) This reaction offers an alternative to the Winig reaction, which may be very sensitive to reaction conditions. 

Propagation reactions involving the fluoro-olefins, vinyl fluoride (VF)6Q 7 vinylidene fluoride (VF2)69 7""74 and trifluoroethylene (VF3),75 show relatively poor rcgiospccificity. This poor specificity is also seen in additions of small... 

During ozonolysis of vinyl fluoride an explosive solid residue is produced, and the volatile ozonide, trapped at —63°C, may explode spontaneously or dining removal by syringe [1]. During the cryogenic distillation of the ozonide (formulated as a trioxolane), several explosions occurred, and the explosive reaction residue was destroyed by digestion with 5% potassium iodide solution for 24 h [2],... 

Many vinyl monomers were reported to have been grafted onto fluoropolymers, such as (meth)acrylic acid and (meth)acrylates, acrylamide, acrylonitryl, styrene, 4-vinyl pyridine, N-vinyl pyrrolidone, and vinyl acetate. Many fluoropolymers have been used as supports, such as PTFE, copolymers of TFE with HFP, PFAVE, VDF and ethylene, PCTFE, PVDF, polyvinyl fluoride, copolymers ofVDF with HFP, vinyl fluoride and chlorotrifluoroethylene (CTFE). The source of irradiation has been primarily y-rays and electron beams. The grafting can be carried out under either direct irradiation or through the use of preliminary irradiated fluoropolymers. Ordinary radical inhibitors can be added to the reaction mixture to avoid homopolymerization of functional monomers. 

Although vinyl fluoride was prepared around 1900, it was believed to be resistant to typical vinyl polymerization. German scientists prepared vinyl fluoride through reaction of acetylene with hydrogen fluoride in the presence of catalysts in 1933. 

The enol ether 1-methoxycyc/ohexene reacts with A/-[ F]fluoropyridinium triflate to give 6-[ F]fluoro-1-methoxycyc/ohexene in 67% radiochemical yield (Scheme 19) [83], Notice that the reaction leads to an allylic and not vinylic fluoride. 

Along the same line, the reactions of vinyl fluorides with nucleophiles often involve addition-elimination processes. The addition reaction generates a carban-ion, and this latter induces the loss of a fluoride. As the loss of a fluoride ion is irreversible, the equilibrium is displaced toward the formation of the carbanion and, consequently, the reaction is very efficient. These reactions are often concerted ones (Figure 1.11). 

Vinyltrimethylstannanes react with xenon difluoride in dichloromethane at room temperature in the presence of equimolar (or a 50 Vo excess) of silver trifluoromethanesulfonate and a catalytical (0.1 equiv) quantity of 2,6-di-/e/7-butyl-4-methylpyridine to form the corresponding vinyl fluorides in high to moderate yields.54 57 The substitution reaction is tolerant to various functional groups, such as ketones, esters, carbamates, ketals, ethers, phenol rings and tertiary alcohols. As byproducts corresponding alkenes have been detected due to pro-tiodestannylation. 

The fluorination of ketones with DAST may result in the formation of vinyl fluorides, e.g. 5, in addition to gew-difluoro compounds. If vinyl fluorides are the desired product, this reaction can be promoted by carrying out the fluorination procedure in 1,2-dimethoxyethane in the presence of fuming sulfuric acid.51... 

Hydrogen fluoride can also be added to acetylene with aluminum trifluoride catalysis to yield vinyl fluoride (14) and 1,1-difluoroethane (15).41 See Table 3 for reactions and byproducts under similar conditions. 

Nitrosyl fluoride reacts with steroidal olefins to give, ultimately, a-fluo-roketones [1311, with steroidal vinyl fluorides, the reaction provides a,a di fluoroketones from intermediate nitroimmes [197] (equation 34)... 

Ozomdes (1,2,4-trioxolanes) are generally obtained by the reaction of fluoroalkenes with ozone Thus, vinyl fluoride is oxidized to monofluoroozomde and formyl fluoride [2J] (equation 15) The same ozonide is formed by ozonolysis of a mixture of cis 1,2-difluoroethylene with ethylene [24]... 

Vinyl fluorides,1 Fluoro(phenylsulfonyl)methylithium (2), obtained by reaction of 1 with BuLi in THF at — 78°, reacts with carbonyl compounds to form fluorohydrins (3), which are dehydrated to (E)-a-fluoro-a,p-unsaturated sulfones (4) in 67-92% yield with CH3S02C1 or orthophosphoric acid. Conversion of 4 into vinyl fluorides (5) is effected with aluminum amalgam (—90% yield). The vinyl fluorides are obtained as a 1 1 mixture of (E)- and (Z)-isomers. 

The reaction of vinyl fluoride with CN has been studied by the DFT B3YLP/6-31+G(d) method.8 This nucleophilic substitution is mainly a n attack with a barrier height of 14.8 kcal mol, which is 17.91 kcalmol 1 more favourable than the a attack. 

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