Fully fluorinated

Fluorination of naphthalene in a stream of dilute fluorine over cobalt trifluoride yields a mixture of perfluorodecalins and partially fluorinated naphthalene derivatives that are fully fluorinated to perfluorodecalins by a subsequent treatment with dilute fluorine [23] Perfluorodecalins are also final products ot fluorination of tetralin over cobalt trifluoride at 250 °C. A more thorough investigation of this reacPon revealed seven additional compounds as products and intermediates [//] (equation 6). 

Fluonnation of isoquinoline gave a mixture of partly and fully fluorinated compounds of which perfluoro-3,4,5,6,7,8-hexahydroisoqumoline and perfluoromethylcyclohexane were fully identified [28] (equation 11)... 

The term fluorous biphase has been proposed to cover fully fluorinated hydrocarbon solvents (or other fluorinated inert materials, for example ethers) that are immiscible with organic solvents at ambient conditions. Like ionic liquids the ideal concept is that reactants and catalysts would be soluble in the (relatively high-boiling) fluorous phase under reaction conditions but that products would readily separate into a distinct phase at ambient conditions (Figure 5.5). 

Perfhioroalko] (Teflon) (PFA) was introduced in 1972 and is a fully fluorinated polymer that is melt-processible with better melt flow and molding properties than the FEP. The PFA has excellent resistance to chemicals. It can withstand acids as well as caustic materials. PFA has better mechanical properties than FEP above 300°F (149°C) and can be used up to 500°F (260°C) for some applications. The low physical strength and high cost of this polymer limit use for some applications. 

DCE interface in the presence of TPBCl [43,82]. The accumulation of products of the redox reactions were followed by spectrophotometry in situ, and quantitative relationships were obtained between the accumulation of products and the charge transfer across the interface. These results confirmed the higher stability of this anion in comparison to TPB . It was also reported that the redox potential of TPBCP is 0.51V more positive than (see Fig. 3). However, the redox stability of the chlorinated derivative of tetra-phenylborate is not sufficient in the presence of highly reactive species such as photoex-cited water-soluble porphyrins. Fermin et al. have shown that TPBCP can be oxidized by adsorbed zinc tetrakis-(carboxyphenyl)porphyrin at the water-DCE interface under illumination [50]. Under these conditions, the fully fluorinated derivative TPFB has proved to be extremely stable and consequently ideal for photoinduced ET studies [49,83]. Another anion which exhibits high redox stability is PFg- however, its solubility in the water phase restricts the positive end of the ideally polarizable window to < —0.2V [85]. 

PFCs are a large group of chemicals characterized by a fully fluorinated hydro-phobic chain and an hydrophilic head. These compounds are often used as coating... 

It possesses outstanding barrier properties to gases, especially water vapor. It is surpassed only by the fully fluorinated polymers in chemical resistance. A few solvents dissolve it at temperatures... 

Fluorinated polymers, especially polytetrafluoroethylene (PTFE) and copolymers of tetrafluoroethylene (TFE) with hexafluoropropylene (HFP) and perfluorinated alkyl vinyl ethers (PFAVE) as well as other fluorine-containing polymers are well known as materials with unique inertness. However, fluorinated polymers with functional groups are of much more interest because they combine the merits of pefluorinated materials and functional polymers (the terms functional monomer/ polymer will be used in this chapter to mean monomer/polymer containing functional groups, respectively). Such materials can be used, e.g., as ion exchange membranes for chlorine-alkali and fuel cells, gas separation membranes, solid polymeric superacid catalysts and polymeric reagents for various organic reactions, and chemical sensors. Of course, fully fluorinated materials are exceptionally inert, but at the same time are the most complicated to produce. 

As was noted above, functional fluoropolymers produced by copolymerization of fluoroolefins with functional PFAVE have several unique properties, with the main disadvantage of these materials being the extremely high cost of functional monomers and the resulting high cost of the functional polymers produced from them. The fact that they are so expensive limits their wider industrial application in other fields such as catalysis and membrane separation, except for chlorine-alkali electrolysis and fuel cells, where the only suitable materials are fully fluorinated polymers because of the extreme conditions associated with those processes. 

PFCs comprise a large group of compounds characterized by a fully fluorinated hydrophobic linear carbon chain attached to one or more hydrophilic head. PFCs repel both water and oil, and are therefore ideal chemicals for surface treatments. These compounds have been used for many industrial applications including stain repellents (such as Teflon), textile, paints, waxes, polishes, electronics, adhesives, and food packaging [1]. 

Bis(dichloroboryl)benzene (6) is an important starting material which lends itself to facile derivatization. As shown by Piers, it cleanly reacts with bis(penta-fluorophenyl)zinc to afford the corresponding bidentate Lewis acid 13 (Scheme 7) The molecular structure of diborane 13 has been determined and is shown in Fig. 1. In this structure, the vicinal boron atoms are held at 3.26 A and from one another and seem to be ideally positioned to cooperatively interact with monoatomic anions. The fully fluorinated version of this bidentate Lewis acid has also been prepared. Original efforts focused on the use of 1,2-bis(dichloroboryl)tetrafluorobenzene 14 as a starting material (Scheme 8). This compound could be observed in the early stage of the reaction of trimeric perfluoro-o-phenylenemercury (4) with boron trichloride, but was found to be unstable toward condensation into 9,10-dichloro-9,10-dihydro-9,10-diboraoctafluoroanthracene 15. The successful synthesis of the fully fluorinated... 

The thenoyltrifluoroacetate (tta) complex, [Sc tta)3 OP(OBu)3)], has been prepared. Scandium also afforded, with l,2-dihydroxybenzene-3,5-disodium sulphonate (Tiron), a monoprotonated chelate below pH 2.5, but above pH 6.0 hydrolysis afforded a monohydroxo-Sc-Tiron complex. Ligand-exchange equilibria for the piperidium salts of [Y(ffac)4] and [Y(tfac)4] have been studied by n.m.r. spectroscopy. The fully fluorinated ligands appear to exchange faster than the partially fluorinated species, and the mixed compounds, [Y(Hffac) (tfac)4 ] , n = 0 — 4, were obtained. 

In addition to CFCs and their replacements, there are some fully fluorinated compounds that are emitted to the atmosphere during various industrial processes, including the manufacture of HCFCs and HFCs. Because of the strong C-F bonds, these compounds have long atmospheric lifetimes (e.g., see Cicerone, 1979 and Ravishankara et al., 1993) and hence have been used as tracers to determine the age of stratospheric... 

Although not fully fluorinated, HFC-23 (CHF3) also has a long lifetime ( 250 years WMO, 1995) because its reaction with OH is slow, k298 = 2.8 X 10 1(1 cm1 molecule-1 s-1 (DeMore et al., 1997). A major source is the production of HCFC-22 (CHC1F2), where HFC-23 is a byproduct. As the use of HCFC-22 and its atmospheric levels have increased (Fig. 13.6), the levels of HFC-23 would be expected to increase as well, and indeed, this is the case. Oram et al. (1998) reported the first atmospheric measurements of this compound at Cape Grim, Australia. HFC-23 increased from 2 ppt in 1978 to 11 ppt in 1995, with a growth rate of 5% per year in 1995. 

It was claimed that fully fluorinated lower members, such as CH3.CH3 N2 are explosively unstable and that treatment of fully fluorinated lower members, such as CFgCOOH. with LiAl hydride causes expin. Another fluorine compd which might cause an expln is Ethylene Tetra-fluoride, which is described in this Vol, p E291-L... 

Among the reductive methods of preparing azoxy compounds is the reduction of aliphatic nitroso compounds with stannous chloride. Triethyl phosphite has been used for the bimolecular reduction of fully fluorinated aromatic nitroso compounds. 

Products from this process range from partially fluorinated through to fully fluorinated materials. Certain functional groups, e.g., acyl fluorides, esters, and some cyclic structures, are retained after fluorination. 

The process usually yields fully fluorinated products, with the great benefit that certain important functional groups are retained in the products. 

It can be seen that ECF tended to produce a higher proportion of fully fluorinated compounds in the product mixture compared with cobalt trifluoride, particularly at lower temperatures. The partially fluorinated products were found to have greater toxicities. 

Table 2.1 lists a number of dioxole monomers and indicates their ability to homopolymerize and/or copolymerize with TFE in CFC-113 solution. The copolymerization of dioxoles with chlorine in the 4 and 5 position of the dioxole ring further demonstrates the very high reactivity of this ring system. Thus an almost infinite number of dioxole polymers can be prepared with one or more comonomers in varying proportions. We have chosen to focus our present work on copolymers of TFE and PDD to preserve the outstanding thermal and chemical properties of perfluorinated polymers. At this point it should be noted that fully fluorinated ethers are nonbasic and effectively possess the same chemical inermess as fluorinated alkanes. Perfluorinated ether groups in polymers are even less reactive as a result of their inaccessibility to chemical reagents. 

Clearly, Greek or Latin numeral roots in conjunction with numerical locants can be used to indicate the number and positions of fluorine substituents in any type of organo-fluorine compound or group, ranging from monofluorinated systems, e.g. 2-fluorobutane (1), to perfluorinated entities, e.g. l,l,l,2.2,3,4,4,4-nonafluoro-3-iodobutane(2). Fluorine locants may be omitted, and often are in non-indexing situations when naming simple and therefore easily visualized fully fluorinated aliphatic/cycloaliphatic or monocyclic aromatic compounds or groups, e.g. octafluoropropane (3), hexafluorocyclopropane (4), pentafluoropropanoic acid, (5). pentafluorophenyl (6). 

In the early 1970 s, the American Chemical Society authorized an alternative system for naming fully fluorinated compounds or groups in which the symbol F conveys the sense of perfluoro . This system, which has its roots in phi-nomenclature (e.g., (/(-heptane is 1) proposed in the 1940s, has not been used widely enough to warrant adopting it in this book. According to -nomenclature, for example, 2 is F-ncopcntanc, 3 is F-propene, 4 is F-pro-panal, 5 is bromo-F-benzene, and 6 is ethyl F-ethyl ether. 

Fully fluorinated carbons with the empirical formula CFX (where x > 1) arc hydrophobic, snow-white in color, and inert towards strong acids (aqua regia, hydroiodic acid), strong alkalis and nascent hydrogen. They are also insoluble in organic solvents. Polycarbon monofluoride or CF, u is a crcam-colored material, a very poor conductor, and has properties close to CFX where x > 1. 

Several partially and fully fluorinated aromatics have been further fluorinated. Fluoro- and 1,4-difluorobenzene give13 the same products as benzene over potassium tetrafluorocobalt ate(lll), in keeping with the current theory5 of fluorination. 

The methylpyridines over cesium tetrafluorocobaltate(III) at 270-340°C also react to give97 significant quantities (10-37% of the product mixtures) of polyfluoropyridines (4-7 compounds, most of which have the ring fully fluorinated with the methyl groups converted into difluoromethyl or trifluoromethyl groups) and perfluoro(alkylpyrrolidines) (23-58%) in overall yields of about 30-35%. 

Ionic fully fluorinated alkoxides of the heavier alkali metals may be prepared by the reaction between the anhydrous metal fluoride and various perfluorinated carbonyl compounds in donor solvents (equations 40 and 41).137... 

Harmer et al.28,29 have reported the synthesis of 1,1,2,2-tetrafluoroethanesulfonic acid, CF2HCF2SO3H, and 1,1,2,3,3,3-hexafluoropropanesulfonic acid, CF3CFHCF2-SO3H, by the addition of sulfite to fluorinated double bonds [Eq. (2.12)]. The product acids have lower volatility, which makes their handling easier, and are expected to have similar acidity values to those of their fully fluorinated counterparts. In fact, catalytic conversions of a range of transformations were found to be comparable to triflic acid (see Chapter 5). 

Fairly complete fluorination gave a mixture of the fully fluorinated, the deca(trifluor-omethyl) and the deca(trifluoromethyl)monofluoro compounds. This product exploded when scraped with a spatula. It subsequently proved possible to isolate the deca(tri-fluoromethyl) component. This too exploded on scraping, but not from percussion. 

Halocarbons. Sodium in carbon tetrachloride,9-11 chloroform, dichloromethane and chloromethane,9 10 and tetrachloroethane9,10 forms shock- and impact-sensitive mixtures. Any aliphatic halocarbon (except fully fluorinated alkanes) may be expected to behave in... 

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