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The solubility, density, and refractive index data for 1,2-propanediol + Cs2SO4 + H2O, ethylene glycol + Cs2SO4 + H2O, and glycerin + Cs2SO4 + H2O ternary systems were determined at 15°C, 25°C, and 35°C. In all cases, the solubility of Cs2SO4in aqueous solutions decreased significantly due to the presence of the polyhydric alcohol. The experimental density, refractive index, and solubility data of saturated solutions for these systems were correlated using polynomial equations. Furthermore, the refractive index and density of unsaturated ternary solutions were also determined and correlated with salt concentrations and proportions of polyhydric alcohol in these systems. [ABSTRACT FROM PUBLISHER]

The mean activity coefficients for CsCl in N-methylformamide or urea ( w) + HO (1 − w) systems were determined in this work by potentiometry, using ion-selective electrodes at 298.15 K. The value of mass fraction w was varied between 0.00 and 0.40 in five unit-steps and the molality of CsCl was between 0.0020 and 1.4009 mol·kg. The experimental data have been correlated with the Pitzer, modified Pitzer and the extended Debye-Hückel equations. The resulting values of the mean activity coefficients, the osmotic coefficients and the standard Gibbs energy of transfer, together with the Pitzer ion-interaction parameters ( β, β and C), extended Debye-Hückel parameters ( a, c and d), and modified Pitzer parameters ( b, B, C) are reported for the investigated systems. [ABSTRACT FROM AUTHOR]

Abstract The Solubility, density and refractive index of the formamide(FA)/ N -methylformamide(NMF)/ N , N -dimethylformamide(DMF) + rubidim bromide/cesium bromide+ water ternary systems were determined at (283.15, 298.15 and 313.15) K. The solubility of the RbBr and CsBr decrease significantly when adding amides into the aqueous solution. The variation trend of density is consistent with solubility, and the change of the refractive index is different. The isothermal experimental solubility was correlated by the NRTL model and the UNIQUAC model. The isothermal solubility, density and refractive index of the ternary systems were fitted by the four parameter equation. Moreover, the mean activity coefficients of the FA/NMF/DMF + RbBr/CsBr + H 2 O systems at experimental temperatures were obtained through the UNIQUAC model. Besides, to investigate the temperature effect on the solid-liquid equilibrium, the multiple temperatures solubility was fitted by the modified Apelbl at equation and the λh equation. Graphical abstract The phase behavior of FA/NMF/DMF (1) + RbBr/CsBr(2) + H 2 O (3) systems were investigated at 283.15, 298.15 and 313.15K. Unlabelled Image Highlights • FA/NMF/DMF + RbBr/CsBr + H 2 O ternary systems were investigated. • Solubility, density and refractive index of SLE systems were determined. • The mean activity coefficients of the systems were obtained by the UNIQUAC model. [ABSTRACT FROM AUTHOR]

In this paper, the potentiometric method was carried out to investigate the thermodynamic properties of the RbF + Rb 2 SO 4 + H 2 O and CsF + Cs 2 SO 4 + H 2 O ternary systems over total ionic strengths from (0.01–0.70) mol·kg −1 for different ionic strength fractions y B of Rb 2 SO 4 /Cs 2 SO 4 with y B = 0.00, 0.30, 0.60 and 0.90, at 298.2 K. The Harned model and the Pitzer model were used to correlate the experimental data. The Harned coefficients and the Pitzer mixing parameters were evaluated by multiple linear regression technique. Moreover, the mean ionic activity coefficients of RbF/CsF and Rb 2 SO 4 /Cs 2 SO 4 , the osmotic coefficients, and the excess Gibbs energies of the studied systems were calculated, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] The phase equilibria of Formamide (FA)/ N -Methylformamide (NMF)/ N, N -Dimethylformamide (DMF) + Rb 2 SO 4 + H 2 O ternary system at three temperatures (T = 288.2, 298.2 and 308.2 K) were studied by isothermal dissolution method. The effects of temperature and amide structure on the isothermal solubility, density and refractive index of the system were discussed. • The solid–liquid equilibrium of FA/NMF/DMF + Rb 2 SO 4 + H 2 O was investigated; • The saturated solubility decreases with the increase of amide content; • Higher temperature increases the solubility of Rb 2 SO 4 in mixed solvents; • Multiple factors contribute to the density and refractive index of at different temperatures. In this work, the solid–liquid equilibrium (SLE) of the ternary systems formamide (FA)/ N -methylformamide (NMF)/ N, N -dimethylformamide (DMF) + Rb 2 SO 4 + H 2 O was measured at temperatures of 283.2, 298.2, and 313.2 K. The isothermal solubility of Rb 2 SO 4 in mixed solvents, the density and refractive index of the saturated solutions were determined. At a given temperature, with the increase of the amide content in the mixed solvent, the saturated solubility of Rb 2 SO 4 decreased significantly. The density trend was consistent with the solubility. However, the refractive index increased with increasing the content of amide. The solubility increased with increasing the temperature, whereas, the density curves and refractive index curves at the three temperatures showed a point of intersection. In addition, the influence of the polarity and structure of amide on the solubility of the ternary system was also discussed. Finally, the experimental data were fitted with empirical equations. [ABSTRACT FROM AUTHOR]

Abstract: The mean ionic activity and osmotic coefficients of CsNO3 in methanol–water and ethanol–water mixed solvent at 298.15K have been determined herein utilizing the potentiometric method. The potential measurements were carried out on a cell, Cs-ISE/CsNO3 (m), ROH (w), H2O (1− w)/NO3-ISE, in the mixed solvent containing w =(0.00, 0.10, 0.20, and 0.30) mass fraction of alcohol. The activity coefficients were calculated from the experimental E value and fitted via the extended Debye–Hückel, Pitzer and the modified Pitzer model equations. The osmotic coefficients, the primary hydration number (n hydr), excess Gibbs free energy and standard Gibbs energies of transference of CsNO3 from the water to the methanol+water or ethanol+water mixtures have also been discussed. [Copyright &y& Elsevier]

Wereport herein the solid–liquid equilibria (SLE) of N,N-dimethylacetamide (DMA) + MCl (M =Na, K, Rb, and Cs) + H2O ternary systems for the firsttime. At the three given temperatures (T= 298.15K, 308.15 K, and 318.15 K), the solubilities, densities, and refractiveindices for these ternary systems are determined with the mass fractionof DMA in salt-free solvent system ranging from 0.0 to 1.0. The solubilityof salts decreases significantly with the addition of DMA, and thesalting-out ratios are calculated accordingly. The nonrandom two-liquid(NRTL) model can effectively fit the experimental solubility. Furthermore,to investigate the temperature effect on the SLE, the dynamic solubilitymeasurement system is selected to determine the solubility of thesalts in the mixed solvent (wDMA= 0.3,0.5, and 0.7) with the temperature continuously increased. The solubilitydata at multiple temperatures are well fitted by the modified Apelblatequation and the λhequation. [ABSTRACT FROM AUTHOR]

Thesolubility, density and refractive index of RbCl/CsCl + [Cnmim]Cl (n= 2, 4, 6, 8)+ H2O saturated systems have been studied at T= (288.15, 298.15 and 308.15) K. The solubility data were correlatedby the nonrandom two-liquid (NRTL) model and an empirical equation.Both models can qualitatively represent the equilibrium behavior.In addition, the results denote that all the ionic liquids triggersalting-out effects with the order: [C2mim]Cl > [C4mim]Cl > [C6mim]Cl > [C8mim]Cl.Thedensity and refractive index of the saturated solutions were determinedfor describing the relationship between the physical property andcomposition of the solution. [ABSTRACT FROM AUTHOR]

Thesolubility, density, refractive index, and viscosity data forthe ethylene glycol + CsBr + H2O, 1,2-propanediol + CsBr+ H2O, and glycerin + CsBr + H2O ternary systemshave been determined at (288.15, 298.15, and 308.15) K. In all cases,the solubility of CsBr in aqueous solutions was decreased significantlydue to the presence of polyhydric alcohol. The liquid–solidequilibrium experimental data were correlated using the NRTL (nonrandomtwo-liquid) activity coefficient model, considering nondissociationof the dissolved salt in the liquid phase, and new interaction parameterswere estimated. The mean deviations between calculated and experimentalcompositions were low, showing the good descriptive quality and applicabilityof the NRTL model. The refractive indices, densities, and viscositiesfor the unsaturated solutions of the three ternary systems have alsobeen measured at three temperatures. Values for all of the propertieswere correlated with the salt concentrations and proportions of polyhydricalcohol in the solutions. [ABSTRACT FROM AUTHOR]

Abstract: In this work, thermodynamic properties measurement for KCl/RbCl/CsCl in N,N-dimethylacetamide (DMA) (w)+H2O (1− w) systems (where the w =0.10, 0.20, 0.30) was carried out by potentiometric method using ion-selective electrodes at 298.15K. Modeling of the activity coefficients of these ternary systems was based on the Pitzer, the modified Pitzer and the extended Debye–Hückel equations. Meanwhile, the osmotic coefficients, the standard free energy of transference from the water to the mixture have also been reported. [Copyright &y& Elsevier]

This article deals with the meanactivity coefficients of RbF orCsF in the glycine + water mixed systems. The Pitzer, the modifiedPitzer, and the extended Debye–Hückel equations areused to describe the nonideal behavior of the electrolyte. The osmoticcoefficients, the excess Gibbs free energy, and the standard Gibbsenergies of transfer were calculated with the corresponding parameters. [ABSTRACT FROM AUTHOR]

• Rb 2 SO 4 + RbBr + H 2 O and Cs 2 SO 4 + CsBr + H 2 O were selected as the research systems. • Stable solid–liquid equilibrium was investigated and discussed. • One invariant point, two univariant curves, and three crystallization regions are observed. • The refractive index of the saturated were determined and fitted. The phase equilibrium and physic-chemical properties of Rb 2 SO 4 (1)-RbBr(2)-H 2 O(3)/Cs 2 SO 4 (1)-CsBr(2)-H 2 O(3) systems at T = (288.15, 298.15 and 308.15) K were determined by the isothermal solution saturation method. At the three temperatures, the two systems both contain one invariant point, two univariant curves, and three crystallization regions. The Schreinemaker's wet residue method and X-ray powder diffraction method were used to verify the solid phase. The phase diagrams of Rb 2 SO 4 (1)-RbBr(2)-H 2 O(3) and Cs 2 SO 4 (1)-CsBr(2)-H 2 O(3) at the three temperatures show that higher temperature reduces the area of the crystallization region of the salts (RbBr and CsBr). The comparison of the two systems at 298.15 K suggests that the crystallization region area of the salts is strongly affected by the solubility and hydration ability of the salts. The refractive index of these systems reached the maximum at the invariant point. At different temperatures, the refractive index increases with increasing temperatures. The results in this paper may provide useful information for the separation of the salts from aqueous solution. [ABSTRACT FROM AUTHOR]

• MCl + TMU + H 2 O systems (M = Na, K, Rb, Cs; TMU = tetramethylurea). • LLE systems of CsCl + TMU + H 2 O at 298.2 and 308.2 K. • SLE system of CsCl + TMU + H 2 O at 288.2 K. • SLE systems of NaCl/KCl/RbCl + TMU + H 2 O at 288.2, 298.2 and 308.2 K. • Affecting factors of temperature, solubility and solvent properties are discussed. For this article, we investigated the phase behavior and physicochemical properties of the ternary systems MCl (M = Na, K, Rb, Cs) + tetramethylurea (TMU) + H 2 O at temperatures of 288.2, 298.2 and 308.2 K. For (solid–liquid) equilibrium (SLE) systems (NaCl/KCl/RbCl + TMU + H 2 O at three temperatures and CsCl + TMU + H 2 O at 288.2 K), the density, solubility and refractive index about the saturated solutions was obtained. About (liquid–liquid) equilibrium (LLE) systems (CsCl + TMU + H 2 O at 298.2 and 308.2 K), the binodal curves and tie lines were obtained. The three parameter equation, Othmer-Tobias and Bancroft equations were used to correlate the SLE and LLE data. [ABSTRACT FROM AUTHOR]

For this article, a number of thermodynamic properties for MCl (M = Na, K, Rb, Cs) in tetramethylurea (TMU)-water ternary systems were investigated through potentiometric method at the temperature of 298.2 K. To fit experiment data, the Pitzer equation and the extended Debye-Hückel equation were used. The mean activity coefficients, together with excess Gibbs free energy, osmotic coefficients and standard solubility product of ternary systems are calculated. The variation of these properties in this ε r -decreasing co-solvent (TMU-H 2 O) is discussed from the aspect of ion radius, relative permittivity, ion-ion interactions and ion-solvent in the solution. Unlabelled Image • MCl + TMU + H 2 O systems (M = Na, K, Rb, Cs; TMU = tetramethylurea) • Thermodynamic properties of MCl + TMU + H 2 O by potentiometric method • The Pitzer and extended Debye-Hückel equations were used for correlation. • Electrostatic interaction and solvation influence the properties. [ABSTRACT FROM AUTHOR]