Cobalt trifluoride process

GL 12] [R 5] [P 9] [P 10] [P 11] Significantly lower temperature can be used to achieve a yield of the perfluorinated product as high as when employing the conventionally used cobalt trifluoride process with traditional reactors [15]. 

The industrial scale procedure probably most important for synthesis of per-fluorocarbon-based solvents was developed during the Manhattan Project [12] (Figure 2.2). In the so-called cobalt trifluoride process (recently commercialized by F2 Chemicals as the Flutec process) [13] the large fluorination enthalpy is harnessed by dividing the reaction into two less exothermic steps. In the first step, CoFj is oxidized with fluorine, at 350 °C, to CoFj. In the second step, the organic... 

Figure 2.2 Schematic representation of the apparatus used to perform the cobalt trifluoride process (courtesy of the American Chemical Society) [13].

Scheme 2.27 Industrial-scale methods for reductive defluorination—aromatization of perfluorocycloaliphatic precursors, which again are accessible by the cobalt trifluoride process [74].

Pentafluorobenzene. Pentafluoroben2ene has been prepared by several routes multistage saturation—rearomati2ation process based on fluorination of ben2ene with cobalt trifluoride reductive dechlorination of chloropentafluoroben2ene with 10% pabadium-on-carbon in 82% yield (226,227) and oxidation of penta uorophenylbydra2ine in aqueous copper sulfate at 80°C in 77% yield (228). Its ioni2ation potential is 9.37 V. One measure of toxicity is LD q = 710 mg/kg (oral, mouse) (127). 

The preparation of perfluorinated compounds is largely based on the exhaustive fluorination of the corresponding hydrocarbon species and three synthetic procedures have been widely used. Two of these processes, electrochemical fluorination [27] (ECF), successfully used for the preparation of perfluoroacids (3M), and fluorination by high valent metal fluorides [28] such as cobalt trifluoride (itself prepared from cobalt difluoride and fluorine), used for the preparation of perfluorocarbons (Flutec fluids, BNFL), have been reviewed elsewhere. The third major process for the preparation of perfluorinated compounds involves direct fluorination. 

It is now reasonably well established that cobalt trifluoride fluorinations proceed via a one-electron transfer oxidative process [74, 75] as outlined in Figure 2.17. 

Formation of perfluorinated ethers by cobalt trifluoride is generally a low-yielding process, because of fragmentation and partial fluorination. However, incorporation into the substrate of electron-withdrawing polyfluoroalkyl groups moderates the fluorination and allows high yields to be obtained [78]. 

Perfluorinated molecules are prepared from their hydrocarbon analogues by electrochemical fluorination or by fluorination using cobalt trifluoride. Functional perfluorinated molecules are then used to prepare the tagged catalysts and reagents (Figure 7.4). Therefore, in terms of life cycle analysis, fluorous solvents are not as green as a solvent that does not need to be prepared, e.g. water, or a solvent that requires little substrate modification, e.g. a renewable VOC. However, the ability of FBSs to perform efficient separations often reduces the overall amount of solvent that is required in a process and therefore they are considered green alternative solvents. 

Further fluorination of perfluoroaromatic compounds328,329 occurs quite smoothly in many cases, using cobalt trifluoride and related reagents (Eq. 94). These reactions are of course much easier to control than fluorinations of the corresponding parent compounds containing hydrogen and the dimeric compound (103), obtained from perfluoropyrimidine, presents some of the best evidence for a radical cation process for this type of reaction (Scheme 29). Even direct fluorination of pentafluoropyridine, with fluorine of low... 

Cobalt fluoride (C0F3) Cobalt trifluoride Cobaitic fluoride EINECS 233-062-4. Used as a fluorinating agent in the fluorination of hydrocarbons (Fowler process). Solid d = 3.88 reacts with air and H2O. Atomergic Chemetals Cerac, ElfAtochem N. Am. 

Low-molar-mass poly(butadiene) oils with 80%-97% cw-1,4 contents are produced with other Ziegler catalysts (for example, cobalt compounds with alkyl aluminum chlorides or nickel compounds with trialkyl aluminum and boron trifluoride-etherate). The products have few cross-links and dry as fast as wood oil and faster than linseed oil. Conversion of the poly (butadiene) oils with 20% maleic anhydride gives air-drying (air-hardening) alkyd resins. Modified poly (butadiene) oils stabilize erosion-endangered soils. Because of its low viscosity, the aqueous emulsion penetrates the surface soil layers. The surface crust is reinforced by an oxidative bonding process. Since no skin is formed on the soil crust, the aqueous absorption characteristics of the soil are retained. 

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