Perfluoro compounds

CFC-113, CF2CICFCI2, or the hydrochlorofluorocarbons (HCFCs) such as HCFC-123, CF2CHCI2, HCFC-141b, or CH2CFCI2, are miscible in all proportions with the perfluoro compounds at 25°C. Typical solubiHty data are shown in Table 2. 

Early waterproofing treatments consisted of coatings of a continuous layer impenetrable by water. Later water-repellent fabrics permitted air and moisture passage to improve the comfort of the wearer. Aluminum and zirconium salts of fatty acids, siUcone polymers, and perfluoro compounds are apphed to synthetic as well as natural fibers. An increase in the contact angle of water on the surface of the fiber results in an increase in water repeUency. Hydrophobic fibers exhibit higher contact angles than ceUulosics but may stiU require a finish (142). 

Fluorodiazirines are obtained from suitable perfluoro compounds by reduction. Difluorodiazirine (218) was prepared from perfluoromethylenediamine (290) by reduction with ferrocene (66JHC245), or from perfluoroformamidine (291) by iodide reduction (67JOC1944). 

C [22, 28] (equation 10) Nitrogen-free perfluoro compounds such as perfluorocyclohcxene, perfluorocyclohcxane, perfluoromethylcyclohexane, and perfluoroheptane result from fragmentation [22, 28]... 

The high thermal and chemical stability of fluorocarbons, combined with their very weak intermolecular interactions, makes them ideal stationary phases for the separation of a wide variety of organic compounds, including both hydrocarbons and fluorine-containing molecules Fluonnated stationary phases include per-fluoroalkanes, fluorocarbon surfactants, poly(chlorotrifluoroethylene), polyfper-fluoroalkyl) ethers, and other functionalized perfluoro compounds The applications of fluonnated compounds as stationary phases in gas-liquid chroma... 

Aromatic Perfluoro-compounds. Part IV. The Reaction of Aromatic Polyfluoro-compounds with Nitrogen-containing Bases," G. M. Brooke, J. Burdon, M. Stacey, and J. C. Tallow, J. Chem. Soc., (1960) 1768-1771. 

The sulfenyl carboxylate is, on complete exclusion of moisture, a stable, colorless liquid, which on irradiation with UV light decomposes to FC(0)SCFs and CO2. The sulfane is a good starting material for the synthesis of additional perfluoro compounds By means of fluorine-chlorine substitution with BCI3 (20°C, 2 days), it is possible to obtain C1C(0)SCF3, whose existence previously could be shown only by mass spectrometric study of the products of irradiation of a mixture of CFsSCl and CO (237). As an acid chloride, ClC(0)SCFs can be esterified with alcohols, but hydrolysis to the free acid fails. 

It has been pointed out that, if a chromatographic system contains perfluoro compounds, as in valves, seals, or separators, trimethylsilyl derivatives may react with them to give spurious peaks. One such peak was identified as that from fluorotrimethylsilane.211... 

Decafluoroanthracene (10a) yields after reaction with nitronium tetrafluoroborate in tetra-methylenesulfone the perfluoro compound 11a only, which is more stable in the reaction media than the partially fluorinated lib. So 10b forms, under comparable conditions, a mixture of lib and 12b.96... 

Rearrangements are even more extensive35 with longer chain hydrocarbons (only ca. 50 % of the octane skeleton is retained when octane is fluorinated over CoF3), and it follows from this that earlier work on the fluorination of such compounds can be discounted since all of the perfluoro compounds claimed would have been mixtures of isomers. 

With the larger rings, rearrangements are even more extensive and none of the original ring structures arc preserved in the perfluoro compounds obtained. All these rearrangements are believed47 to proceed via carbocations early in the fluorinations. 

Hydrocarbon ethers have been fluorinated only partially with the reagents under discussion no recent attempts have been made to fluorinate as far as the perfluoro compounds. These ethers are clearly more reactive than hydrocarbons, as much lower temperatures are required to produce comparable degrees of fluorination. However, yields of fluoro products are usually poor. 

Thermally induced elimination of fluorine occurs if polyfluorocycloalkanes, -cyclohexadienes or some heterocyclic perfluoro compounds arc passed over a nickel or iron gauze at 500-700cC (examples are summarized in Table 7). Within a certain time the catalytic activity of the metal decreases and it has to be regenerated by passing hydrogen over it at 300-600JC. The yields... 

These often are called perfluoro- compounds, which indicates that all available hydrogens of the parent compound are replaced by fluorine. Thus per-fluorocyclohexane is (CF2)e- A widely used perfluorocarbon is the plastic material -FCF2-)t7, which is produced in quantity by radical polymerization of tetrafiuoroethene ... 

Electrochemical fluorination of alkylpyridines proceeds in much the same way as for pyridine itself (Section II,A). The Simmons process gave low yields of perfluoro compounds, the major portion of which resulted from ring fragmentation.208 Somewhat surprisingly, the yields of perfluoropiperidines... 

Furin and co-workers prepared several fluorinated diazetines by the reaction of perfluoro compound 131 with isopropyl amine, /-butyl amine, 2-amino-6-bromobenzothiazole, and 2-amino-1-methyl imidazole in THF in the presence of triethylamine (Equation 32) <2000RJ0109>. The same group also reported the formation of several diazetidines 132 and 133 by the reaction of perfluoro compound 131 with 2-nitro-, 4-nitro-, or pentafluoro-aniline in the presence of triethylamine (Scheme 15, Section 2.13.7.2) <2000JFC(104)263>. 

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