Solubility of fluorocarbons

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The resistance to 02 and C02 transport of the liquid membrane should be minimal. The liquid membranes are typically quite thin. In systems where they have been measured, they are usually 1 or less, which is substantially thinner than polymeric membranes used for tran-port. The thinness of the membranes combined with the high solubility of fluorocarbons (13, 14) for 02 and C02 would be expected to lead to minimal liquid membrane resistance to transport. 

Using DMF as a solvent to facilitate solubility of fluorocarbons and thus ease conditions of the reaction, Wu and Chen prepared indolizines and 4//-pyrrolo[ 1,2-a] benzimidazoles in good yields by 1,3-dipolar cycloaddition of fluoroalkenes to N-ylides, exemplified below by the synthesis of indolizine 75 (Fig. 3.34). ... 

Gorski, R. A., R. B. Ramsey, and K. T. Dishart. 1985. Physical Properties of Blowing Agent Polymer Systems-I. Solubility of Fluorocarbon Blowing Agents in Thermoplastic Resins. 29th... 

Teddy and Wheeler [201] have described the three-component phase diagram for the ammonium perfluorooctanoate/octanol-water system. The phase structure was determined by optical microscopy. Octanol was found to be four times less soluble in ammonium perfluorooctanoate solutions than in sodium oc-tanoate solutions. The low solubility of octanol was attributed to a low mutual solubility of fluorocarbon and hydrocarbon chains and not to different counterions, ammonium versus sodium. However, the ammonium counterion may have contributed to the high solubility of ammonium perfluorooctanoate in octanol. 

Pozzi has also reported a fluoro-functionalised tetraazacyclotetradecane macrocycle, which is selectively soluble in fluorocarbons and active in the fluorous biphasic oxidation of hydrocarbons. [59] This ligand (Figure 6.17) was produced whilst... 

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... 

Although absorption of fluorocarbons via inhalation is rapid, and maximal blood concentrations are reached in about 15 min, pulmonary uptake is low (Azar et al. 1973 Trochimowicz et al. 1974 Mullin et al. 1979). Negligible metabolism and tissue retention take place. Blood concentrations fall rapidly following cessation of exposure as the parent compound is exhaled unchanged. Rapid elimination is typical of poorly soluble materials with high vapor pressures and demonstrates a lack of potential to bioaccumulate (Emmen et al. 2000). 

Alternatively, we have shown that CO2 can be used to induce miscibility of fluorocarbon-hydrocarbon mixtures (see Figure 1), even those involving polar compounds such as methanol (2). Fluorinated organometallic complexes have been well established to have significant solubility in supercritical CO2, and their use as catalysts in this medium is well developed (10). This allows the homogeneously catalyzed reaction to be carried out in the C02-expanded homogeneous solution. 

The mole fraction solubilities of ten copper(II) and five chromium(III) P-diketo-nates were measured in SCCO2 with a spectroscopic technique and found to vary over four orders of magnitude. Observed trends indicate that the solubility in supercritical carbon dioxide is strongly dictated by the character of the hydrocarbon or fluorocarbon shell surrounding the central metal atom. A regular solutions approach was used for Cr(acac)°3 to quantitatively attempt to predict the solubility in SCCO2. Solubility... 

The rate of Ostwald ripening depends on the size, the polydispersity, and the solubility of the dispersed phase in the continuous phase. This means that a hydrophobic oil dispersed as small droplets with a low polydispersity already shows slow net mass exchange, but by adding an ultrahydrophobe , the stability can still be increased by additionally building up a counteracting osmotic pressure. This was shown for fluorocarbon emulsions, which were based on perfluo-rodecaline droplets stabilized by lecithin. By adding a still less soluble species, e.g., perfluorodimorphinopropane, the droplets stability was increased and could be introduced as stable blood substitutes [6,7]. 

Ans. Use a phosphine with a fluorinated alkyl group so that a 5.1 type of fluorocarbon-soluble precatalyst is formed in situ (see I. T. Horvath and J. Rabi, Science 266, 72-75, 1994). 

Fluorous solvents would seem to be particularly suitable for performing aerobic oxidations, based on the high solubility of oxygen in fluorocarbons, a prop-... 

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