Binary aqueous system, phase

The binary aqueous systems phase diagrams in the range of the crystallization of TBA carboxylate and isocarboxylate polyhydrates are given in Figures 1 and 2 respectively, and some properties of the hydrates are shown in Table I. Two hydrates with stable crystallization branches form in the TBA acetate - water system. One stable and several metastable hydrates have been discovered in each of the rest of the systems (from 1 (TBA formate) to 8 (TBA o-butyrate)). 

The work presented here is essentially a preliminary study of the solubilization of oil in simple binary aqueous systems which can be used as model systems for microemulsions. Still, it was demonstrated that the use of phase separation to recover the oil... 

In this expression xi and x / are the compositions of component 1 in the two phases. For most binary aqueous systems, when xi, the mole fractions of component 1 in water, is small, xi/, and therefore y f are both close to one. This results in the approximation yi = 1/xi. This approximation is valid at the solubility concentration xi. 

Once the interaction energies were obtained, they were used to calculate the parameters in the UNIQUAC and Wilson models given by Eq. (24). To test the validity of the method, low-pressure vapor-liquid equilibrium (VLE) predictions were made for several binary aqueous systems. The calculations were done using the usual method assuming an ideal vapor phase (Sandler, 1999). Figures 7 and 8 show the low-pressure VLE diagrams for the binary aqueous mixtures of ethanol and acetone [see Sum and Sandler (1999a,b) for results for additional systems and values of the... 

Yakoumis, l.V. et al.. Prediction of phase equilibria in binary aqueous systems containing alkanes, cycloalkanes, and alkenes with the CPA EoS, Ind. Eng. Chem. Res., 37, 4175, 1998. 

ZA2 Zafarani-Moattar, M.T., Hamzehzadeh, S., and Hosseinzadeh, S., Phase diagrams for liquid-hquid equilibrium of ternary poly(ethylene glycol) + disodium tartrate aqueous system and vapor-liquid equilibrium of constituting binary aqueous systems at r = (298.15, 308.15, and 318.15)K. Experiment and correlation, Fluid Phase Equil, 268, 142, 2008. 

Figure 5. Critical curves for several binary aqueous systems in the vicinity of the critical point of pure water. The shaded side of the curves indicates the two-phase regions. Tlie CeHn-curve is not shaded only because of clarity. The not shaded heavy solid line near the bottom left represents the vapour pressure curve of pure water, ending at the critical point (c.p.) [81]...

Chandler, K., Eason, B., Liotta, C.L. and Eckert, C.A., Phase equilibria for binary aqueous systems from a near-critical water reaction apparatus, Ind. Eng. Chem. Res., 1998, 37, 3515-3518. 

PEO/PPO/PEO triblock copolymers exhibit properties similar to typical surfactants, i.e. they reduce surface and interfacial tension of aqueous solutions and form micellar aggregates above a critical micellar concentration [74, 78]. For some compounds of this type, like P104 (EOigPOsgEOis), P123 (E02oP07oE02o)> 3nd F127 (EO106PO70EO106), a similarly located cubic phase like the one of the aminoxide systems has been found in tbe binary aqueous system [74, 79]. 

W. Maciejewicz and E. Soczewinski, Chemometric characterization of TLC systems of the type silica-binary non-aqueous mobile phase in the analysis of flavonoids. Chromatographia 51 (2000) 473 477. 

The physical chemical behavior of betaine esters of long-chain alcohols shows strong similarities to the common, closely related alkyltrimethylam-monium surfactants both in dilute and concentrated aqueous systems, hi consistence with the findings about CMC s of surfactants containing normal ester bonds (see above) it has been found that the CMC for a betaine ester with a hydrocarbon chain of n carbons is very close to the value for an alkyltrimethylammonium chloride surfactant with a hydrocarbon chain of n + 2 carbons [32], The binary phase diagram of dodecyl betainate-water has an appearance very similar to that of an alkyltrimethylammonium surfactant with a hydrophobic tail of a similar size [30]. 

Solubility of racemic praziquantel was determined in MeOH and 2-PrOH in the temperature range between 0 °C and 40 °C. A ternary phase diagram of praziquantel enantiomers and the MeOH system was also determined (06CH259). The solubility phase and binary melting-point phase diagrams were determined. Experimental and predicted aqueous solubility of praziquantel was reported (07CPB669,08SQE191). Dissolution of praziquantel... 

Reactive absorption processes occur mostly in aqueous systems, with both molecular and electrolyte species. These systems demonstrate substantially non-ideal behavior. The electrolyte components represent reaction products of absorbed gases or dissociation products of dissolved salts. There are two basic models applied for the description of electrolyte-containing mixtures, namely the Electrolyte NRTL model and the Pitzer model. The Electrolyte NRTL model [37-39] is able to estimate the activity coefficients for both ionic and molecular species in aqueous and mixed solvent electrolyte systems based on the binary pair parameters. The model reduces to the well-known NRTL model when electrolyte concentrations in the liquid phase approach zero [40]. 

QSRR Eqs. (11.15) and (11.16) clearly demonstrate that the organic modifier of binary aqueous eluents used in reversed-phase liquid chromatography also modifies the stationary phase. The hydrocarbon brush on the silica matrix adsorbs the modifier and gets to some extent its properties 117]. QSRR enables differences in the mechanism of reversed-phase retention in individual HPLC. systems employing the. same stationary phase material, are characterized in a numerical manner. 

Fig. 4 illustrates a chromatogram of oxalic acid, malonic acid, and succinic acid obtained using the most polar binary solvent system, composed of 1-butanol/water. All components were well resolved from each other and eluted within 2.3 h, using the lower aqueous phase as the mobile phase. 

The nonaqueous systems also form liquid crystals analogous to aqueous systems in ternary systems with an added weakly hydrophilic component. SDS has been extensively employed in studies of ternary and quaternary systems with glycerol or formamide, a long-chain alcohol, and, sometimes, hydrocarbon [97-101], In the SDS-glycerol-decanol system the lamellar phase swells extensively, even more so than in water [97], While no liquid crystals form at room temperature in the binary systems, a D-phase occurs when decanol is added. 

---