The Methane-Acetone System

Data for the methane-acetone system are available by Yokoyama et al. (1985). The implicit LS estimates were computed and found to be sufficient to describe the phase behavior. These estimates are (ka=0.0447, kb=0, kc=0, kd=0). The standard deviation for ka was found to be equal to 0.0079. 

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If the correct phase behavior i.e. absence of erroneous liquid phase splits is predicted by the EoS then the overall fit should be examined and it should be judged whether it is "excellent". If the fit is simply acceptable rather than "excellent", then the previously computed LS parameter estimates should suffice. This was found to be the case for the n-pentane-acetone and the methane-acetone systems presented later in this chapter. 

Data for the methane-acetone system are available by Yokoyama et al. 

Yokoyama C., H. Masuoka, K. Aval, and S. Saito, "Vapor-Liquid Equilibria for the Methane-Acetone and Ethylene-Acetone Systems at 25 and 50°C", J. Chem. Eng. Data, 30, 177-179(1985). 

The chemical ionization mass spectrum of cimetidine and the major fragmentation ions are presented in Figure 8 and Table 4. The spectrum was obtained using a Finnigan lYbdel 3200 quadrupole mass spectrometer fitted with a chemical ionization source. The sample, applied to the probe from an acetone solution, was introduced via the direct inlet system. Methane was used as the reactant gas. 

The oxidation of 3 to 380 can also be achieved with oxyhalo acids [27,28]. In the procedure published by BASF, the oxidation is carried out in the two-phase system dichloro-methane/water and uses as oxidizing agent sodium chlorate in the presence of catalytic amounts of sodium iodide. After the solvent is changed to acetone, pure 380 is obtained in approximately 65% yield (Scheme 10). 

Table 3 shows results obtained from a five-component, isothermal flash calculation. In this system there are two condensable components (acetone and benzene) and three noncondensable components (hydrogen, carbon monoxide, and methane). Henry s constants for each of the noncondensables were obtained from Equations (18-22) the simplifying assumption for dilute solutions [Equation (17)] was also used for each of the noncondensables. Activity coefficients for both condensable components were calculated with the UNIQUAC equation. For that calculation, all liquid-phase composition variables are on a solute-free basis the only required binary parameters are those for the acetone-benzene system. While no experimental data are available for comparison, the calculated results are probably reliable because all simplifying assumptions are reasonable the... 

Dispersive Liquid-Liquid Microextraction The aforementioned SDME method, although it significantly reduces solvent consumption, is not free from drawbacks such as low extraction efficiency and slowly reached equilibrium. In many cases, the extraction efficiency can be increased by using dispersive systems such as the emulsion of organic solvent in an aqueous sample. In dispersive liquid-liquid microextraction (DLLME), a mixture of two solvents (extraction solvent and disperser) is injected by syringe into an aqueous sample. The extraction solvent is a water-insoluble and nonpolar liquid such as toluene, chloroform, dichloro-methane, carbon tetrachloride, or carbon disulfide. A water-miscible, polar solvent, typically acetonitrile, acetone, isopropanol, or methanol, is used as disperser. The typical concentration of extractant in such a mixture is in the range 1-3 %. 

Sensitization by mercury is useful for performing the photoreaction on all those 1,4-dienes that lack chromophoric groups, e.g. alkyl and/or cycloalkyl substituted systems. These reactions appear to proceed by triplet energy transfer from the mercury to give vibrationally exited diene triplets. Thus, at variance with solution phase photoreactions, the exited states possess greater vibrational energy and substantially different products are possible. While such comparison is impossible for the parent system because no solution phase photochemistry has been reported, the di-ir-methane product (4) was not observed when irradiation of the 3,3-dimethyl-substituted diene (3) (equation 3) was carried out under acetone sensitization in solution. Hydrocarbon (4) was the major component under mercury-sensitized conditions in the vapor phase. ... 

To a very good approximation, the excess Gibbs energy for the system acetone(l)/methan is given by... 

McNesby and Gordon " measured the CD3H/CD4 ratio by mass-spectrom-etry, and determined the ratio kn/ku in a system where RH was methane. The CD3 radicals were produced in the temperature ranges 350-428 °C and 475-525 °C by the photolysis and the pyrolysis of acetone, respectively. From the photolytic and pyrolytic data, found to be scattered along the same straight line on the Arrhenius plot of knlk 2> values of = 0.48 and 32 = 2.74 kcal. 

In fact, barrelene rearranges by the di-7t-methane pathway to semibullvalene only when acetone sensitized direct irradiation produces cyclooctatetraene as the major photoproduct. A number of similar examples exist, each demonstrating the general phenomenon of preferred triplet multiplicity for di-7r-methane rearrangements in rigidly constrained systems, i.e. structures which prohibit free rotation about the Ti-bonds. ... 

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