Solubility mole fraction

Fig. 3. The dependence of the solubility (mole fraction) of cerium tribromide in pyridine on temperature (157). The numbers adjacent to the various lines and curves are the respective estimates for enthalpies of solution. 

Table 6.1 provides approximate values of the solubilities (mole fraction atm , i.e., xjp = 1/Hy) of some common gases in water, variations of which are negligible up to pressures of several bars. Note that the solubilities decrease with increasing temperature. It is worth remembering that values of solubility in water are high for NHj moderate for CI2, CO, and low for Oj, Nj. 

Fig. 2. Solubility (mole fraction) of PH in supercritical CO2 at T = 308.15 K, when a cosolvent (methanol) was added (O), experimental solubility [7] ( ), calculated using Eq. (24) (2a) 1 mol% methanol added (2b) 2.5 mol% methanol added.

Deviation from experimental data calculated as MPD (%) (the mean percentage deviation) defined as 100 X XI, where x and are experimental and calculated solubilities (mole fractions), and Nj is the number of experimental points in the data... 

Temperature Drug (K) Pressure (bar) Density (g/cm ) Solubility (mole fraction X 10" ) Ref. 

Solute Solubility (mole fraction) Enhancement factor... 

Solution Naphthalene in benzene. Assuming the two components to form an ideal solution, the solubility (mole fraction) of naphthalene at 40 °C is calculated from eq. fi. ol ... 

In Equation 10.22 through Equation 10.24, X2, x, and X2 are the solubilities (mole fractions) of the solid (component 2) in the cosolvent, water, and their mixture, respectively, Y > and Y2 are the activity coefficients of the solid in its saturated solutions in cosolvent, water, and mixed solvent,/2 (T,p) is the hypothetical fugacity of a solid as a (subcooled) liquid at a given pressure and temperature,/2 is the fugacity of the pure solid (component 2), and x designates that the activity coefficients of the solid depend on composition. If the solubilities of the pure and mixed solvents in the solid phase are negligible, then the left-hand sides of Equation 10.22 through Equation 10.24 depend only on the properties of the solute. 

Their results are schematically given in Fig. (1) one may notice on one hand that the solubility of CO2, in ethanol is the highest, while in viscous liquid, ethyleneglycol, it is the lowest and on the other hand the solubility of CO2 increases with decrease in the solution viscosity. Moreover Belhaj (43) investigated the solubilities of CO2 and N2O in isopropanol, toluene and toluene + 10 % by volume of isopropanol and defined the solubility as the dissolved gas mole fraction, X2 According to his experimental results obtained at 20 C and, shown in Fig. (2), one may conclude that the addition of 10 % by volume of isopropanol to the toluene does not change the solubility mole fraction x. ... 

Figure 22.13 Solubilities (mole fraction x) of polar molecules (sodium chloride, o and glycine, ) in media of different dielectric constants, O. Media of high D are the best solvents, and the lines are predicted by Equation (22.63). Source ...

Figure 24.13 (left) shows the saturation solubilities of PCM in mixtures of ethanol (99 % purity) and CO2 as well as in mixtures of acetone (99 % purity) and CO2 for pressures of 10, 13, and 16 MPa. A similar behavior can also be seen here for the system C02/acetone. The saturation solubility mole fraction of PCM XpcM decreases in concave solubility curves for an increasing carbon dioxide mole fraction xcoj at aU the three pressures measured. Also, the pressure dependency of the saturation solubility is observable, although it is not as distinct as for ethanol-containing systems. 

In addition to the solute PCM, the saturation solubility mole fractions of PVP were also measured in the systems C02/EtOH and C02/EtOH/acetone. As it is a very poor solvent concerning PVP, no measures in pure acetone were conducted. In Fig. 24.13 (right), Fig. 24.14 (left), and Fig. 24.14 (right), the saturation solubility mole fractions of PVP xpvp as a function of the carbon dioxide mole fraction xcot for different solvent compositions at differing pressures are shown. 

The values of the solubility mole fractions are multiplied by a factor of 10 to the power of 6. This clearly shows that PVP qualifies as a sparingly soluble solute in comparison to the previously discussed PCM as not only are the saturation mole fractions lower, but also shifted significantly toward lower carbon dioxide mole fractions. The measured solubility data for PVP (40 kg mol ) in the system CO2/ EtOH and CO2 with different wt% ratios of EtOH to acetone are given in Fig. 24.13 (right), Eig. 24.14 (left), and Fig. 24.14 (right). The solvent composition was varied in terms of wt% of EtOH to acetone in between 70/30, 50/50, and 30/70. The temperature was set constant at 313 K and the pressure in the view cell was varied between 10, 13, and 16 MPa. 

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