Solubilities of betulin in chloroform + methanol mixed solvents at T = (278.2, 288.2, 293.2, 298.2, 308.2 and 313.2) K

Experimental solubilities of betulin in mixed solvents of chloroform (1) + methanol (2) were determined at T = (278.2, 288.2, 293.2, 298.2, 308.2 and 313.2) K. The solubilities of betulin in mixed solvents of chloroform (1) + methanol (2) increase with increasing of temperature. The curves of solubility versus solvent composition on solute-free basis went through a maximum. Experimental data of solubilities were correlated with a three-parameter equation. In addition, three crystals of betulin obtained in different compositions of chloroform (1) + methanol (2) mixtures were characterized by scanning electron microscope (SEM) and differential scanning calorimetry (DSC).     

Solubility of HFCs in lower alcohols

This work is inserted in a research program that consists mainly in the experimental and theoretical study of the effect of association between solute and solvent molecules in the solubility of gases in liquids.The solubilities of hydrofluorocarbons, HFCs, (CH₃F, CH₂F₂, CHF₃) in lower alcohols (methanol, ethanol, 1-propanol, 1-butanol) have been determined in the temperature range [284, 313] K, at atmospheric pressure. An automated apparatus based on Ben-Naim-Baer and Tominaga et al. designs was used, which provides an accuracy of 0.6%. A precision of the same order of magnitude was achieved.To represent the temperature dependence of the mole fraction solubilities, the equation R ln x₂ = A + B/T + C ln T was used. From this equation, the experimental Gibbs energies, enthalpies and entropies of solution at 298 K and 1 atm partial pressure of the gas, were calculated.A semiempirical correlation has been developed between the solubilities of HFCs in alcohols at 298 K and the Gutmann acceptor number of solvents, AN, and reduced dipole moment of the gases, μ*.     

Physical properties and their corresponding changes of mixing for the ternary mixture acetone + n-hexane + water at 298.15 K

Experimental density and the refractive index of the ternary mixture acetone + n-hexane + water, and their binary systems were experimentally measured and correlated at 298.15 K and atmospheric pressure. A maximum in refractive indices has been observed for the acetone + water system while the excess molar volume and the molar refraction change are all negative. For the mixture acetone + n-hexane, the excess molar volume is always positive and the molar refraction change of mixing showed a S-shaped dependence on acetone composition. The excess molar volumes and molar refraction changes of mixing were correlated using the Redlich-Kister expression and Cibulka equation. The coefficients and standard deviation between the experimental and fitted values were estimated. Good agreement between both results was obtained.     

Experimental measurement and modeling of solubility of LiBr and LiNO3 in methanol, ethanol, 1-propanol, 2-propanol and 1-butanol

The solubility of lithium bromide and lithium nitrate in solvents methanol, ethanol, 1-propanol, 2-propanol and 1-butanol were measured in the range between 298.15 and 338.15 K using an analytical gravimetric method. An empirical equation was used to fit the experimental solubilities and the Pitzer model with inclusion of Archer's ionic strength was used for the calculation of osmotic coefficients. The experimental data of system pressures (p) for the correlation of LiBr + ethanol, LiBr + 2-propanol at T (298.15-333.15 K) and LiNO₃ + ethanol at T (298.15-323.15 K) were obtained from published literatures. Moreover, the parameters of the Pitzer model were re-correlated and were used to predict mean ion activity coefficients. A procedure was also presented to predict the solubility products of salts in pure organic solvent.     

Physical properties of 3-methyl-N-butylpyridinium tricyanomethanide and ternary LLE data with an aromatic and an aliphatic hydrocarbon at T = (303.2 and 328.2) K and p = 0.1 MPa

Several physical properties were determined for the ionic liquid 3-methyl-N-butylpyridinium tricyanomethanide ([3-mebupy]C(CN)₃): liquid density, viscosity, surface tension, thermal stability and heat capacity in the temperature range from (283.2 to 363.2) K and at 0.1 MPa. The density and the surface tension could well be correlated with linear equations and the viscosity with a Vogel-Fulcher-Tamman equation. The IL is stable up to a temperature of 420 K.Ternary data for the systems {benzene + n-hexane, toluene + n-heptane, and p-xylene + n-octane + [3-mebupy]C(CN)₃} were determined at T = (303.2 and 328.2) K and p = 0.1 MPa. All experimental data were well correlated with the NRTL model. The experimental and calculated aromatic/aliphatic selectivities are in good agreement with each other.     

Enthalpy of mixing in 0.8[xB2O3-(1 − x)P2O5]-0.2Na2O glasses at 298 K

0.8[xB₂O₃-(1 − x)P₂O₅]-0.2Na₂O (with 0 ≤ x ≤ 1) glasses have been characterized by solution calorimetry at 298 K in acid solvent. The experimental data showed a strong negative departure of the enthalpy of mixing from the ideality described by the equation (in kJ/mol): ΔH = x(1 − x)(−660.2 + 570x). The results were interpreted on the basis of the structural data. Enthalpies of mixing were consistent with sub-regular solution behaviour.     

New isothermal vapor–liquid equilibria for the CO2 + n-nonane,and CO2 + n-undecane systems

Experimental vapor–liquid equilibria (VLE) for the CO₂ + n-nonane and CO₂ + n-undecane systems were obtained by using a 100-cm³ high-pressure titanium cell up to 20 MPa at four temperatures (315, 344, 373, and 418 K). The apparatus is based on the static-analytic method; which allows fast determination of the coexistence curve. For the CO₂ + n-nonane system, good agreement was found between the experimental data and those reported in literature. No literature data were available for the CO₂ + n-undecane system at high temperature and pressure. Experimental data were correlated with the Peng–Robinson equation of state using the classical and the Wong–Sandler mixing rules.     

Solid-liquid phase equilibria in the system water + methanol + MgSO4·7H2O + MnSO4·4H2O

The solubilities and complex phase equilibria for the system of MnSO₄·4H₂O + MgSO₄·7H₂O + H₂O + CH₃OH were determined at the temperatures 291.2 and 301.2 K over the methanol mole fraction range of 0.00–0.12.The solubility data were used for modelling with the modified extended electrolyte non-random two-liquid equation. The salting-out effect of MgSO₄ and methanol on the solubilities of two manganese salts (MnSO₄·H₂O and MnSO₄·4H₂O) are represented in the several thermodynamic figures as a function of temperature. The solventing-out effect was stronger than the salting-out effect, which results in a decrease of the solubilities of manganese, salts even though the solubility of MnSO₄·H₂O decreased and solubility of MgSO₄·4H₂O increased as temperature increased.     

Volumetric properties of the boldine + alcohol mixtures at atmospheric pressure from 283.15 to 333.15 K: A new method for the determination of the density of pure boldine

Densities of boldine + alcohol binary mixtures were measured over the whole accessible range of boldine compositions at temperatures from 283.15 to 333.15 K using an Anton-Paar digital vibrating glass tube densimeter. The binary systems studied include, as a solvent, seven normal alcohols from n-C₁ to n-C₆, n-C₈, and isopropanol. The density of these systems has been found an increasing function of the boldine composition. A new methodology based on density data of solutions of solid solutes with normal alcohols is described in order to determine solid molar volume of pure solutes. This methodology was validated with pure solid naphthalene molar volumes data at 298.15 K, with an average uncertainty of 6%.     

Phase diagram of Na2S2O3 + ethanol + water at ambient pressure and temperature

In the present communication, we report the studies concerning liquid–liquid–solid equilibria for the ternary system sodium thiosulphate (Na₂S₂O₃) + ethanol + water at ambient pressure and at room temperature (303 ± 2 K). The solubility data of Na₂S₂O₃ are reported for solutions in water, ethanol and solutions of varying concentrations of ethanol in water. The phase diagram for the said system is developed, described and compared with similar system K₂CO₃ + methanol + water. These results have been explained in terms of structural properties of aqueous ethanol solutions and further discussed in terms of the effect of ions to cause phase separation.     

High-pressure vapor–liquid equilibria for CO2 + alkanol systems and densities of n-dodecane and n-tridecane

An apparatus based on the static-analytic method was used to measure the vapor–liquid equilibria (VLE) for CO₂ + alkanol systems. Equilibrium measurements for the CO₂ + 1-propanol system were performed from 344 to 426 K. For the case of the CO₂ + 2-propanol system, measurements were made from 334 to 443 K, and for the CO₂ + 1-butanol were obtained from 354 to 430 K. VLE data were correlated with the Peng–Robinson equation of state using the classical and the Wong–Sandler mixing rules. Moreover, compressed liquid densities for the n-dodecane and n-tridecane were obtained via a vibrating tube densitometer at temperatures from 313 to 363 K and pressures up to 25 MPa. The Starling and Han (BWRS), and The five-parameter Modified Toscani-Swarcz (MTS) equations were used to correlate them. The experimental density data were compared with those from literature, and with the calculated values obtained from available equations for these n-alkanes.     

Construction of solid-liquid phase diagrams in ternary systems by titration calorimetry

Titration calorimetry was used to construct the solid-liquid equilibrium line in ternary systems containing the solute and an aqueous mixed solvent by measuring the heat of dissolution of the solid solute during successive additions of the liquid solvent. The plot of cumulated heats versus the mole ratio, n_solvent/n_solute, yields two (almost) linear increases of different slopes. These two lines represent successively the enthalpy of dissolution then the enthalpy of dilution of the medium; their intersection gives the solubility and the enthalpy of dissolution of the solute. Phase diagrams have been established over the whole concentration range for o-anisaldehyde, 1,3,5-trimethoxybenzene and vanillin, in water + methanol, +ethanol, or +n-propanol at 303, 313 and 318 K.     

Separation of propylbenzene and n-alkanes from their mixtures using 4-methyl-N-butylpyridinium tetrafluoroborate as an ionic solvent at several temperatures

Liquid-liquid extraction is the most common method for separation of aromatics from their mixtures with n-alkanes hydrocarbons. An ionic liquid (IL), 4-methyl-N-butylpyridinium tetrafluoroborate [(mebupy)(BF₄)], was evaluated as solvent for this separation. Liquid equilibria (LLE) for 2 ternary systems comprising tetradecane, or hexadecane + propylbenzene + [(mebupy)(BF₄)] were measured over a temperature range of 313-333 K and atmospheric pressure. The reliability of the experimental data was evaluated using the Othmer-Tobias correlation. The effect of temperature, n-alkane chain length and solvent to feed ratio upon solubility, selectivity, and distribution coefficient were investigated experimentally. In addition, the experimental results were regressed to estimate the interaction parameters between each of the 3 pairs of components for the UNIQUAC and the NRTL models as a function of temperature. Both models satisfactorily correlate the experimental data, however the UNIQUAC fit was slightly better than that obtained with the NRTL model.     

Solid–liquid equilibrium and hydrogen solubility of trans-decahydronaphthalene + naphthalene and cis-decahydronaphthalene + naphthalene for a new hydrogen storage medium in fuel cell system

Solid–liquid equilibrium was measured for benzene + cyclohexane, trans-decahydronaphthalene + naphthalene and cis-decahydronaphthalene + naphthalene under the atmospheric pressure in the temperature range from 226.69 to 353.14 K. The apparatus was specially designed in this study, and it was based on a cooling method. The phase diagram with the complete immiscible solids was observed for the three systems, and the eutectic point was found at x₂ = 0.2709 and T_eu = 232.11 K for benzene + cyclohexane, x₂ = 0.9816 and T_eu = 241.98 K for trans-decahydronaphthalene + naphthalene, and x₃ = 0.9822 and T_eu = 225.74 K for cis-decahydronaphthalene + naphthalene, respectively. Hydrogen solubility was also measured for the two pure substances, trans-decahydronaphthalene and cis-decahydronaphthalene, and the three mixtures, trans-decahydronaphthalene + cis-decahydronaphthalene, trans-decahydronaphthalene + naphthalene, and cis-decahydronaphthalene + naphthalene, in the pressure range from 1.702 to 4.473 MPa at 303.15 K. Considering the solid–liquid equilibrium data, mole ratio of trans-decahydronaphthalene:cis-decahydronaphthalene was set to 50:50, and those of trans-decahydronaphthalene + naphthalene, and cis-decahydronaphthalene + naphthalene to 85:15. The hydrogen solubility increased linearly with the pressure following the Henry's law for all systems. The experimental solubility data were correlated or predicted with the Peng–Robinson equation of state [D.Y. Peng, D.B. Robinson, Ind. Eng. Chem. Fundam. 15 (1976) 59–64; R. Stryjek, J.H. Vera, Can. J. Chem. Eng. 64 (1986) 323–333].     

Solubilities of ammonia in basic imidazolium ionic liquids

Solubilities of ammonia in four conventional imidazolium ionic liquids: [C_nmim][BF₄] (n = 2, 4, 6, 8) have been measured. Isothermally fixed temperatures are 293.15, 303.15, 313.15, 323.15 and 333.15 K; the pressure is from 0 to 1.0 MPa. High solubilities of ammonia are found, and it is also found that the solubilities of ammonia increase when the length of cations’ alkyl increases (the ILs have the same anion), that is: [C₈mim]⁺ > [C₆mim]⁺ > [C₄mim]⁺ > [C₂mim]⁺. The solubility data have been correlated by the Krichevisky–Kasarnovsky equation, and then Henry's constants and partial molar volumes of NH₃ at infinite dilution are obtained. The thermodynamic properties such as solution enthalpy (Δ_solH), solution Gibbs free energy (Δ_solG), solution entropy (Δ_solS), and solution heat capacity (Δ_solC_p) of these systems are obtained.     

Vapor-liquid equilibria at 333.15 K and excess molar volumes and deviations in molar refractivity at 298.15 K for mixtures of diisopropyl ether, ethanol and ionic liquids

In this work, we have studied influence of ionic liquids (ILs) on the azeotrope composition for the system {diisopropyl ether (DIPE) + ethanol} using trihexyltetradecylphosphonium chloride ([P_666,14][Cl]) and trihexyltetradecylphosphonium bis(2,2,4-trimethylpentyl) phosphinate ([P_666,14][TMPP]). Isothermal vapor-liquid equilibrium data at 333.15 K are reported for the ternary systems {DIPE + ethanol + [P_666,14][Cl]} and {DIPE + ethanol + [P_666,14][TMPP]} with varying the mole fraction of ILs from 0.05 to 0.10. The experimental ternary VLE data were correlated using the Wilson equation. In addition, excess molar volumes (V^E) and deviations in molar refractivity (ΔR) data at 298.15 K are reported for the binary systems {DIPE + [P_666,14][Cl]} and {ethanol + [P_666,14][Cl]} by a digital vibrating tube densimeter and a precision digital refractometer. The V^E and ΔR were correlated by the Redlich-Kister equation.     

Complex formation of crown ethers with cations in the (water + organic solvent) mixtures: Part IX. Thermodynamics of interactions of Na ion with benzo-15-crown-5 ether in {(1 − x)DMA + xH2O} at T = 298.15 K

The thermodynamic functions of complex formation of benzo-15-crown-5 ether with sodium cation in {(1 − x)DMA + xH₂O} at T = 298.15 K have been calculated. The equilibrium constants of complex formation of benzo-15-crown-5 ether with sodium cation have been determined by conductivity measurements. The enthalpic effect of complex formation has been measured by calorimetric method at T = 298.15 K. The complexes are enthalpy stabilized and entropy destabilized. A simple model has been proposed to describe the relationship between the thermodynamic functions of complex formation of crown ethers with sodium cation and the structural and energetic properties of the mixed water-organic solvent. The linear enthalpy-entropy relationship for complex formation is also presented. The solvation enthalpy of the complex in {(1 − x)DMA + xH₂O} is discussed.     

Thermodynamic representation of the NaCl + Na2SO4 + H2O system with electrolyte NRTL model

A comprehensive thermodynamic model based on the electrolyte NRTL (eNRTL) activity coefficient equation is developed for the NaCl + H₂O binary, the Na₂SO₄ + H₂O binary and the NaCl + Na₂SO₄ + H₂O ternary. The NRTL binary parameters for pairs H₂O-(Na⁺, Cl⁻) and H₂O-(Na⁺, SO₄²⁻), and the aqueous phase infinite dilution heat capacity parameters for ions Cl⁻ and SO₄²⁻ are regressed from fitting experimental data on mean ionic activity coefficient, heat capacity, liquid enthalpy and dissolution enthalpy for the NaCl + H₂O binary and the Na₂SO₄ + H₂O binary with electrolyte concentrations up to saturation and temperature up to 473.15 K. The Gibbs energy of formation, enthalpy of formation and heat capacity parameters for solids NaCl_(s), NaCl·2H₂O_(s), Na₂SO_4(s) and Na₂SO₄·10H₂O_(s) are obtained by fitting experimental data on solubilities of NaCl and Na₂SO₄ in water. The NRTL binary parameters for the (Na⁺, Cl⁻)-(Na⁺, SO₄²⁻) pair are regressed from fitting experimental data on dissolution enthalpies and solubilities for the NaCl + Na₂SO₄ + H₂O ternary.     

Isobaric vapor–liquid equilibria for the n-hexane + 2-isopropoxyethanol and n-heptane + 2-isopropoxyethanol systems

Vapor–liquid equilibria (VLE) for the n-hexane + 2-isopropoxyethanol and n-heptane + 2-isopropoxyethanol (at 60, 80, and 100 kPa) systems were measured. Two systems present positive deviations from ideal behavior. And the system n-heptane + 2-isopropoxyethanol shows a minimum boiling azeotrope at all pressures. Experimented data have been correlated with the two term virial equation for vapor-phase fugacity coefficients and the three suffix Margules equation, Wilson, NRTL, and UNIQUAC equations for liquid-phase activity coefficients. Experimental VLE data show excellent agreements with models.     

Modeling of the three-phase equilibrium in systems of the type water + nonionic surfactant + alkane

Liquid–liquid equilibria of systems water (A) + C_iE_j surfactant (B) + n-alkane (C) have been modeled by a mass-action law model previously developed and so far successfully applied to a series of binary water + C_iE_j systems and to the ternary system water + C₄E₁ + n-dodecane. These calculations provide the basis for the presented modeling. The aqueous systems give information about the association constants and the χ_AB-parameter of the Flory–Huggins theory and the ternary C₄E₁-system provides universal temperature functions for the χ_AC- and the χ_BC-parameter. The three-phase equilibrium for seven ternary C_iE_j systems (i = 6–12, j = 3–6) has been calculated by fitting one additional parameter for each of both temperature functions to the characteristic “fish-tail” point. The agreement with the experimental data is reasonably well. For systems with very small three-phase areas the results can considerably be improved by individual temperature functions that incorporate the experimental temperature maximum of the “fish” into the parameter fit. Based on the parameters of the system water + C₈E₄ + n-C₈H₁₈ the “fish-shaped” phase diagram of the system water + C₈E₄ + n-C₁₄H₃₀ was predicted reasonably well.