Solubility isotherms

The solubilities of Li, Na, and Ca hypochlorites in H2O at 25°C ate 40, 45, and 21%, respectively. Solubility isotherms in water at 10°C have been determined for the following systems Ca(OCl)2—CaCl2, NaOCl—NaCl, and Ca(OCl)2—NaOCl (141). The densities of approximately equimolar solutions of NaOCl and NaCl ate given in several product bulletins (142). The uv absorption spectmm of C10 shows a maximum at 292 nm with a molar absorptivity of 350 cm ( 5)- Heats of formation of alkali and alkaline earth hypochlorites ate given (143). Thermodynamic properties of the hypochlorite ion ate ... 

The compound (NIDsNbaOFig can be prepared by adding ammonium fluoride, NH4F, to a solution containing Nb (3.20 M/l) and F (27.10 M/l). The solubility isotherm (25°) of this compound is presented in Fig. 5. The minimum point on the solubility isotherm approximately corresponds to the stoichiometrical ammonium-niobium ratio of the compound (NfLOsNbsOFig. 

Based on a comprehensive investigation of solubility isotherms and of conductometric and potentiometric titration in the NbF5 - HF - H2O system, Nicolaev and Buslaev [288] concluded that H2NbOF5 is the predominant niobium-containing form present in such solutions. 

The first comprehensive investigation of the TaF5 - HF - H2O system was performed by Buslaev and Nikolaev [292]. Based on the analysis of solubility isotherms, and on conductometric and potentiometric titrations, the authors concluded that in this solution, tantalum forms oxyfluorotantalic acid, H2TaOF5, similar to the formation of H NbOFs in solutions containing NbF5. 

Figure 24 shows the ternary phase diagram (solubility isotherm) of an unsolvated conglomerate that consists of physical mixtures of the two enantiomers that are capable of forming a racemic eutectic mixture. It corresponds to an isothermal (horizontal) cross section of the three-dimensional diagram shown in Fig. 21. Examples include A-acetyl-leucine in acetone, adrenaline in water, and methadone in water (each at 25°C) [141].

Figure 25 shows the ternary phase diagram (solubility isotherm) for an unsolvated racemic compound. Examples of this type include benzylidenecamphor in methanol, or /V-acetylvaline in acetone [141]. In Fig. 25, A and A represent the...

Fig. 25 Solubility isotherm for an unsolvated racemic compound. (Reproduced with permission of the copyright owner, John Wiley and Sons, Inc., New York, from Ref. 141, p. 193.)...

Figure 26 shows the ternary phase diagrams (solubility isotherms) for three types of solid solution. The solubilities of the pure enantiomers are equal to SA, and the solid-liquid equilibria are represented by the curves ArA. The point r represents the equilibrium for the pseudoracemate, R, whose solubility is equal to 2Sd. In Fig. 26a the pseudoracemate has the same solubility as the enantiomers, that is, 2Sd = SA, and the solubility curve AA is a straight line parallel to the base of the triangle. In Figs. 26b and c, the solid solutions including the pseudoracemate are, respectively, more and less soluble than the enantiomers. 

In what may well prove to be only the first in a series, solubility isotherms have been reported for MF3/MCl3/water systems, for M = Y, La, and Gd (277). ... 

This is the hydrogen solubility isotherm. For low concentrations Ch this equation approaches Sievert s equation ... 

Fig. 3. Solubility isotherms for the system Na2B407—B20,—H20 at 0—60°C. The compound 2Na20-5.1B203-7H20 (Suhr s borate) usually does not appear...

Fig. 8. Solubility isotherms for the K O—B203—H20 system at temperatures from 5 to 95°C where A, B, C, and D represent the solid phases B(OH)3,...

To determine the composition of bimetallic alkoxides formed via complex formation in solution and in the solid phase and to estimate their stability, we have applied physicochemical analysis — the investigation of the solubility isotherms in the systems M(OR)m- M (OR)n - L (solvent alcohol, ether, hydrocarbon, etc.). This method, common for the studies ofthe interaction of inorganic salts in water solutions, turned out to be rather fruitful in the chemistry of alkoxides. It permitted the study of the interaction ofthe components... 

The liquid a-form is not represented by a singular point in the solubility isotherm. The IR and H of these samples contain the sums of the signals for Al(OR)3 and Al3Cl5(OR)4, and their mass-spectra arc also the fragments of Al40(0Pii)5[H(0Pri)2]Cl4 [1657]. 

Fig. 6. Solubility isotherm for the system NajO- Oj-HjO. From Doonan and Lower...

Dlepen and Scheffer ( 6) were the first to show that near either the lower or upper critical end point the solubility of a solid in a supercritical fluid is enhanced and also very sensitive to changes in temperature and pressure our solubility isotherms show this effect for both end points. First, the isotherms cross at about 140 bar so that the solubility at the lowest temperature (50.0°C) is largest at 120 bar. This is a result of approaching the lower critical end point region (which should be close to the critical point of pure C02 as previously mentioned). At temperatures and pressures near this LCEP the solubility enhancement results in lower temperature isotherms having the greater solubilities. The effect of the upper critical end point is also well shown by our data. The 58.5°C isotherm shows a large increase in solubility at about 235 bar the slope of the isotherm is near zero. As Van Welie and Diepen... 

Considering the inconsistencies between experimental measurements [29,65,74], as evident in Figures 11-6 and 11-7, our predictions are more or less within the uncertainty range of experimental measurements. For CO2 at 373 K, our calculated Henry s law constant is in close agreement with experiment [65], see Figure 11-6, therefore, the calculated solubility isotherm in Figure 11-7 is also close to the experiment [65],... 

In this paper solubility measurements of synthetic and natural dyestuffs are presented using VIS-spectroscopy. The investigations concentrate on two different methods. I. P-carotene was measured as a function of temperature and pressure in near- and supercritical C02 (289 to 309 K, 10 to 160 MPa) and CC1F3 (297 to 326 K, 12 to 180 MPa), respectively, using a static method. II. Additionally, the solubilities of l,4-bis-(n-alkylamino)-9,10-anthraquinones (with n-alkyl = butyl, octyl) were determined with a dynamic method in temperature and pressure ranges from 310 to 340 K and 8 to 20 MPa, respectively this method permits a continuous purification from better soluble impurities as well as the measurement of solubilities at the same time. For both anthraquinone dyestuffs intersection points of the solubility isotherms were found in the plot of concentration versus pressure. This behavior can be explained by a density effect. 

In discussions of the precipitation of calciinn phosphate, the phase which is usually emphasized is the thermodynamically most stable, HAP. However, most calcium phosphate solutions in which precipitation experiments are made, are initially supersaturated with respect to four additional phases. The solubility isotherms are shown in Figure 1 as a function of pH. Thus, at a pH of 7.0, in order of increasing solubilities, it is necessary to take into account tricalcium phosphate (Ca3(PO )2 hereafter TCP), octacalcium phosphate (Ca H(PO ). 2 1/2 H2O, hereafter OCP), anhydrous dicalcium phosphate (CaHPO, hereafter DCPA), and dicalciiam phosphate dihydrate (CaHPO. 2H2O, hereafter DCPD). The corresponding thermodynamic solubility products. 

Figure 3. Solubility isotherms of myristic, palmitic, stearic, and oieic acids in SCCO2 at 308 K (26).

When the solubility of various minor lipid components were compared with that of selected components of other major lipid classes, it was found that a-tocopherol, oleic acid (a liquid fatty acid), and squalene were the most soluble solutes and p-carotene had the lowest solubility in SCCO2 (Figure 5, solubility isotherms constructed using Equation 2). 

Figure 5. Solubility isotherms of lipid components at 323 K plotted using model parameters estimated using Equation 2.

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