Tetrafluoroethylene pentamer

The tetrafluoroethylene pentamer reacts with aqueous triethylamine, giving dihydrofuran derivative 41 (79JCS(P1)214). 

Note that the reaction of the tetrafluoroethylene pentamer with the alkoxide anion at low temperatures (—30 to —40°C) yields the kinetically controlled product, whereas the thermodynamically controlled product is obtained at 20 °C (94JFC(67)95, 88CJC446). 

In this case, a mixture of cis- and ra s-perfluoro-4,5-dihydro-2,3,4,5-tetramethyl-4-ethylfurans is obtained. This is a general reaction, which also works with other perfluoroolefins and alcohols. For example, when the tetrafluoroethylene pentamer reacts with allyl alcohol in the presence of bases, the initial reaction is nucleophilic addition at the multiple bond, forming olefin 44, followed by the formation of perfluoro-4-ethyl-2,3,4,5-tetramethyl-4,5-dihydrofuran 45 in the presence of KF (87ASCC31). 

Interaction of the tetrafluoroethylene pentamer and -naphthylamine leads to compound 115. 

A tetrafluoroethylene pentamer forms an ester with /7-hydroxymethylben-zoate which can be hydrolyzed to prepare a salt of a fluorinated carboxylic acid... 

Oxidation of a methyl group on a cresyl ether, obtained by reacting p-cresol with the tetrafluoroethylene pentamer, yields a fluorinated carboxylic acid. The acid is neutralized to give a fluorinated surfactant [96,97] ... 

The tetrafluoroethylene pentamer (Fig. 2.7) is allowed to react with phenol. The phenylether formed is treated with oleum to yield a sulfonic acid, which is neutralized with NaOH [96,97] ... 

Oligomerization of tetrafluoroethylene provides intermediates for amphoteric fluorinated surfactants. The tetrafluoroethylene pentamer reacts with phenol to form a phenyl ether [96]. Chlorosulfonation of the phenyl ether with chlorosul-fonic acid yields a sulfonyl chloride, which is allowed to react with A dimethyl-propanediamine ... 

Nonionic surfactants can be prepared by a reaction of the tetrafluoroethylene pentamer with alcohols or with a phenol [96,97]. The reaction product obtained with phenol is sulfonated to produce a sulfonyl chloride. A reaction of the sulfonyl chloride with with iV-ethylethanolamine yields an alcohol, which is oxyethylated to produce a nonionic surfactant ... 

The reaction of the tetrafluoroethylene tetramer and pentamer with ethylacetoacetate gives pyran derivatives 107 and 108, respectively (83JCS(P1)1239, 83JCS(P1)1235). 

The oligomerisation process consists in anionic polymerisation of tetrafluoroethylcne in suitable aprotic solvents, e.g., diglyme or dimethylformamide, using KF, CsF or tetraalkylammonium fluoride as catalyst. The oligomerisation products are branched perfluoroolefins able to by further modified. Trimers, tetramers and pentamers of tetrafluoroethylene as well as dimers and trimers of hexafluoropropylene are useful essentially as a lyophobic backbone of fluorinated surfactants. This approach was initiated by ICI and Neos (Jap.), respectively. 

Anionic telomerization of tetrafluoroethylene with fluoride ion in an aprotic solvent yields mainly tetramer, perfluoro-3,4-dimethylhex- 3-ene, pentamer (57), the major product, and hexamers, mostly (58) and (59). The ICI work on the preparation of novel surface-active agents from, in particular, the pentamer (57) has been... 

Oligomers of tetrafluoroethylene (particularly pentamer) are prepared by oligomerization of tetrafluoroethylene in an organic solvent in the presence of a fluoride compound and a crown ether [280],... 

Perfluorotetramethylfuran 137 and perfluorotrimethylfuran 141 were obtained from pentamer of tetrafluoroethylene 140 in two steps. The first step of the reaction is hydration with formation of fluorinated dihydrofuran derivative. The subsequent heating in the presence of iron or platinum catalyst resulted in 137 or 141 in high yields [105],... 

A process developed by ICI [95-97] is based on anionic polymerization of tetrafluoroethylene. Unlike high-molecular-weight poly(tetrafluoroethylene) produced by free-radical polymerization, anionic polymerization catalyzed by a fluoride (e.g., cesium, potassium, or tetraalkylammonium fluoride) produces highly branched oligomers. The main products are a tetramer, a pentamer, and hexamers (Fig. 2.7). 

Likewise, cationic surfactants are prepared by the oligomerization process. The tetrafluoroethylene tetramer or pentamer is allowed to react with phenol and the phenyl ether obtained is chlorosulfonated [96.97]. The sulfonyl chloride is reacted with A, A -dimethyl-l,3-diaminopropane and quaternized ... 

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