Solvent, fluorocarbon

Reactions with Organic Compounds. Tetrafluoroethylene and OF2 react spontaneously to form C2F and COF2. Ethylene and OF2 may react explosively, but under controlled conditions monofluoroethane and 1,2-difluoroethane can be recovered (33). Benzene is oxidized to quinone and hydroquinone by OF2. Methanol and ethanol are oxidized at room temperature (4). Organic amines are extensively degraded by OF2 at room temperature, but primary aHphatic amines in a fluorocarbon solvent at —42°C are smoothly oxidized to the corresponding nitroso compounds (34). 

These changes in regio- and stereochemistry are likely due to conformation changes and electrostatic factors within the cavity. The intrazeolite oxidations can be improved by use of fluorocarbon solvents, owing to an enhanced lifetime of 102 and to improved occupancy of the cavity by hydrocarbons in this solvent.176... 

Cr(CO)5 interacts with solvent molecules and in solution cannot be considered as naked. The interaction is much weaker with fluorocarbon solvents than hydrocarbon 33). Using a pulsed laser photolysis source (frequency tripled NdYAG) and C7F14 as a solvent, Kelly and Bonneau 33) measured the rate constants for the reaction of Cr(CO)5 with C6H12, CO, and other ligands [Eq. (3)]. 

Surprising is the absence of evidence for additional stability of 85 over 83. Electron donation from the electron-rich a bonds of the cyclopropyl ring to the carbene s vacant p orbital is widely believed to stabilize cyclopropylcarbenes.4 One would therefore expect 85, with an additional cyclopropyl substituent, to react more slowly than either parent carbene 83 or dimethylcarbene, but all three lifetimes are comparable. The lifetimes of 83-85 need to be redetermined in inert (fluorocarbon) solvents in order to reveal their innate differences. Note, however, that the effect of cyclopropyl substitution is apparent upon comparison of 83 (r 24 ns) to MeCH (r < 0.5 ns).89110... 

Dinh is illustrative of the methods and their potential (Figure 4).1261 Hydrosilylation of enones like cydo-hexenone was conducted in two different ways. Under biphasic reaction conditions, an organic solvent like toluene containing the enone and phenyl-dimethyl silane was heated with a fluorocarbon solvent (perfluoromethylcyclohexane) containing a fluorous rhodium catalyst. The hydrosilylation reaction occurred over 10 h, and the reaction mixture was cooled and the phases were separated. Distillation of the residue from the organic phase gave the hydrosilylated products in excellent isolated yields... 

Despite the lack of solubility of 15 in fluorocarbon solvents, the huge retention differences between organic compounds (solvent front) and fluorous-tagged compounds (>30 min for the longer tags) translate into simple separations by solid... 

The preparation of fluorinated alcohols was carried out in multistep routes according to the reported procedures.1012 The synthesis of acrylic and methacrylic esters as shown in Table 11.1 was carried out in a fluorocarbon solvent such as Freon 113 by the reaction of the respective fluorinated alcohol with acryloyl chloride or methacryloyl chloride and an amine acid acceptor such as triethyla-mine with examples shown in Scheme 1. Other attempts to esterify the fluoroalcohols directly with acrylic acid or acrylic anhydride were not successful.11 Product purification by distillation was not feasible because of the temperature required, but purification by percolation of fluorocarbon solutions through neutral alumina resulted in products of good purity identified by TLC, FTIR, and H-, 13C-, and 19F- FTNMRs. 

Oxygen dilluoride reacts with primany amines in fluorocarbon solvents under very cold conditions to form nitroso compounds ... 

White monoclinic crystals density 5.09 g/cm melts at 64°C (triple point) sublimes at 56.6°C critical temperature 232.65°C critical pressure 46 atm critical volume 250 cm /mol reacts with water forming UO2F2 and HF soluble in chloroform, carbon tetrachloride and fluorocarbon solvents soluble in liquid chlorine and bromine dissolves in nitrobenzene to form a dark red solution that fumes in air. 

In the Liquid-Phase Photofluorination [39,44] process the reactant is injected at a very slow constant rate into an inert fluorocarbon solvent which is saturated by fluorine and under U.V. irradiation. Conditions are chosen to ensure that the concentration of fluorine and fluorine radicals is always much higher than the concentration of the substrate. This method is only suitable for the perfluorination of substrates, such as partially fluorinated ethers (see Section 2.5) and amines (see Section 2.7), that are both soluble in perfluorocarbon solvents and can withstand such vigorous reaction conditions. 

Pelosi and Miller have reported the results of an elegant study of the photolytic and thermal isomerizations of C CFj) isomers.42 The anti-dimer of perfluoro(tetramethylcyclobutadiene). anti-21, gives a mixture of perlluoro(octamethylcubane) (22) and perfluoro(octamethylcuneane) (23) in 20% and 15 % yield, respectively, when irradiated for 36 hours in a fluorocarbon solvent [a mixture of perfluoro(1,3- and perfluoro(1,4-dimethylcyclohexane)]. Cubane 22 is presumably formed via xyn-21, whereas 23 is postulated to be formed via intermediates per-lluoro(oclamcthyleyclooctatetraene) (24) and the corresponding scmibullvalene. 

Fluorocarbon solvent polarity (/%) increases when fluorine is substituted by chlorine or hydrogen, and hydrofluorocarbons can be more polar than their hydrocarbon analogues Notably, P/C6H5F) = 7 52 and Ps (1,2 C6H4F2) = 7 86 vs P/C6H6) = 6 95, whereas both CgF17H (Ps = 4 33) and C4F9CH2CH3 (Ps = 4 01) are considerably more polar than then hydrocarbon counterparts [40]... 

This trapped carbene (which actually exists as a dimer with tetra-coordinated Li atoms) smokes on exposure to air and also on grinding with fluorocarbon solvent, from which it seems able to remove fluoride. 

Brennessel, W. W. et al., J. Amer. Chem. Soc., 2002, 124(35), 10258 Pyrophoric, and spontaneously ignites with fluorocarbon solvents even under argon. See also METAL DERIVATIVES OF ORGANOFLUORINE COMPOUNDS See other ORGANOMETALLICS... 

If these shift data really do represent the onset of an intermolecular electron transfer reaction in DABCO, ABCO, HMT clustered with amine, either, and aromatic solvents, one ought to be able to observe the reaction kinetics or dynamics. Consider the specific instance of DABCO. The singlet Rydberg state lifetime for DABCO (and all the other Rydberg molecules studied for this determination (Shang et al. 1993c, 1994a) is ca. 2 ps for the isolated molecule and ca. 1.2 ps for the nonpolar rare gas, hydrocarbon, and fluorocarbon solvents. This... 

C4F9C2H4), are highly fluorophilic and exhibit large partition coefficients in favor of fluorocarbon solvents over common organic solvents due to a double-layered structure where the stannoxane core is covered by fluoroalkyl groups. Fluorous technology allows transesterification and esterification in which 100% yield of the desired esters is achievable with reactants in a strict 1 1 ratio. The tin catalysts are recovered from the fluorous phase quantitatively (Equation (95)).260... 

RhCl P(CH2CH2(CF2)5CF3)3 3 catalyst in fluorocarbon solvents for transformations of organic compounds... 

Mesophase pitch, derived from coal tar, reacts smoothly with fluorine to give pitch fluoride [147, 148] with a composition between CFi 3 and CFi 6, as a yellowish white solid which differs from graphite fluoride in that it is soluble in some fluorocarbon solvents. Consequently, thin films of pitch fluoride may be deposited on materials and the resulting surfaces have been claimed to have even lower surface energies than PTFE. 

Hexafluoro-2-butyne has also been obtained by routes involving fluoride-ion processes, such as by using a fluorocarbon solvent [53] or by passing perfluorocyclobutene over a bed of caesium fluoride or potassium fluoride [293] (Figure 7.84). 

Figure 7.22 Results for the continuous hydroformylation of 1-octene catalysed by Rh/P(4-C6H4C6Fi3)3 in fluorocarbon solvents. (1 = linear isomer, b = branched isomer) [Reprinted with permission from Dalton Trans., 2004, 2062-2064. Copyright 2004 The Royal Society of Chemistry.]...

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