Binary and ternary solubilities of disperse dyes and their blend in supercritical carbon dioxide

Binary and ternary solubilities of C.I. Disperse Blue 134 (1,4-bis(isopropylamino)anthraquinone) C.I. Disperse Yellow 16 (3-methyl-1-phenyl-5-pyrazolone) and their dye mixture in supercritical carbon dioxide (SC-CO₂) were measured by a flow-type apparatus. The solubility measurements were carried out at the pressure ranges from 10.0 to 25.0 MPa for the binary systems at the temperatures from 323.15 to 383.15 K and for the ternary system at 383.15 K. An empirical equation was used to correlate the experimental binary solubilities of the dyes in terms of the density of carbon dioxide. To represent accurately the binary solubility of the dyes in terms of temperature and pressure, we used a modified Peng–Robinson–Stryjek–Vera equation of state (PRSV EOS). The ternary solubilities of the dye blend could be predicted successfully from binary parameters with the modified PRSV EOS.     

The temperature dependence of the solubility of carbon dioxide in several extraction solvents

The solubility of CO₂ in the extraction solvents 1-methyl-2-pyrrolidone, 4-formylmorpholine, γ-butyrolactone, sulfolane and 1,4-dioxane have been measured over the temperature range 303. 15–333.15 K at a partial pressure 1 a1 atm. using the falling-film flow technique. For all systems, the solubility was found to decrease with increasing temperature. Agreement with solubilities predicted by the Redlich-Kwong equation of state for binary systems was within ±3.0%     

Measurement and correlation of solubilities of C.I. Disperse Red 73, C.I. Disperse Yellow 119 and their mixture in supercritical carbon dioxide

The solubilities of disperse dyes and their mixture in supercritical carbon dioxide are important to the fundamental research and development of supercritical fluid dyeing (SFD). The solubilities of Disperse Red 73, Disperse Yellow 119 and their mixture in supercritical carbon dioxide were measured in the temperature range from 343 to 383 K and pressures from 12 to 28 MPa by a static-recirculation method. The results show that over the entire range of experimental conditions in the binary (Disperse Red 73 + CO₂ and Disperse Yellow 119 + CO₂) and ternary (Disperse Red 73 + Disperse Yellow 119 + CO₂) systems, the solubilities increased with increasing pressure and temperature and were clearly affected by the molecular polarity of the dyes. A co-solvent effect and a competing dissolution effect existing in the ternary system led to the increase and decrease in the solubilities of Disperse Yellow 119 and Disperse Red 73, respectively. The solubility data of the two dyes and their mixture were correlated with two empirical models—the Chrastil and the Mendez-Santiago/Teja (MT) model.     

Measurement and prediction of solubilities and diffusion coefficients of carbon dioxide in starch–water mixtures at elevated pressures

The solubility and diffusion coefficient of carbon dioxide in intermediate‐moisture starch–water mixtures were determined both experimentally and theoretically at elevated pressures up to 16 MPa at 50 °C. A high‐pressure decay sorption system was assembled to measure the equilibrium CO₂ mass uptake by the starch–water system. The experimentally measured solubilities accounted for the estimated swollen volume by Sanchez–Lacombe equation of state (S‐L EOS) were found to increase almost linearly with pressure, yielding 4.0 g CO₂/g starch–water system at 16 MPa. Moreover, CO₂ solubilities above 5 MPa displayed a solubility increase, which was not contributed by the water fraction in the starch–water mixture. The solubilities, however, showed no dependence on the degree of gelatinization (DG) of starch. The diffusion coefficient of CO₂ was found to increase with concentration of dissolved CO₂, which is pressure‐dependent, and decrease with increasing DG in the range of 50–100%. A free‐volume‐based diffusion model proposed by Areerat was employed to predict the CO₂ diffusivity in terms of pressure, temperature, and the concentration of dissolved CO₂. S‐L EOS was once more used to determine the specific free volume of the mixture system. The predicted diffusion coefficients showed to correlate well with the measured values for all starch–water mixtures. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 607–621, 2006     

Water Activity and Solubility Measurements and Pitzer Model Simulation of the MgCl<Subscript>2</Subscript>–RbCl–H<Subscript>2</Subscript>O Ternary System at 298.15 K

Water activities for the MgCl₂–RbCl–H₂O ternary system and its sub-binary MgCl₂–H₂O and RbCl–H₂O systems at 298.15 K have been measured using the isopiestic method. The measured results for the binary systems agree well with literature data. The measured equal water activity lines for the MgCl₂–RbCl–H₂O ternary system deviate from Zdanovskii’s rule. The solubilities for the MgCl₂–RbCl–H₂O ternary system also have been measured using a isothermal visual first/last crystal method, and the results are consistent with one reported set of solubility data. Pitzer’s model was selected to correlate the measured water activity and solubility data and the parameters reported in the literature are re-examined by comparing the model-calculated equal water activity lines and solubilities with experimental values measured in this work. New and reasonable parameters are obtained by fitting the water activity and solubility data measured in this work and those reported in the literature. The water activities and solubilities were simulated with the new parameters and the results show that the Pitzer model can successfully represent the thermodynamic properties and be used to calculate the solubility isotherms.     

Solubility in the manganese perchlorate–urea–perchloric acid–water system at 25°С

Heterogeneous equilibria in the manganese perchlorate–urea–perchloric acid–water quaternary system at 25°С were studied by investigating solubility. The crystallization regions were determined for the initial solid components, eutonic compositions of ternary systems constituting the quaternary system, binary compounds of urea with manganese perchlorate and perchloric acid, and also two new coordination compounds containing simultaneously manganese perchlorate, urea, and perchloric acid: Mn(ClO₄)₂ · 4CO(NH₂)₂ · HClO₄ and Mn(ClO₄)₂ · 2CO(NH₂)₂ · HClO₄.     

Interaction in the zinc perchlorate–urea–perchloric acid–water system at 25°С

Heterogeneous equilibria in the zinc perchlorate–urea–perchloric acid–water quaternary system at 25°С were studied by investigating solubility. The crystallization regions were found for the initial solid components, eutonic compositions of the ternary systems constituting the quaternary system, binary compounds of urea with zinc perchlorate and perchloric acid, and also two new coordination compounds containing simultaneously zinc perchlorate, urea, and perchloric acid: ZnClO₄ · 4CO(NH₂)₂ · HClO₄ and ZnClO₄ · 2CO(NH₂)₂ · HClO₄.     

Applcation of the Pitzer equations to the solubility of ternary aqueous nitrate solutions at 25°C

The solubilities of the ternary systems Cu(NO₃)₂–Ca(NO₃)₂–H₂O and Cu(NO₃)₂–Mg(NO₃)₂–H₂O at 25°C were calculated from the solubility data for the binary systems by using the Pitzer equations. The calculated solubility isotherms were confirmed experimentally. The activity coefficients of the components, the osmotic coefficient, and the activity of water were calculated from the experimental isotherms.     

Interaction in the nickel perchlorate–acetamide–perchloric acid–water system at 25°С

Heterogeneous equilibria in the nickel perchlorate–acetamide–perchloric acid–water quaternary system at 25°С were studied by studying solubility. The crystallization regions were determined for the initial solid components, eutonic compositions of the ternary systems constituting the quaternary system, binary compounds of acetamide with nickel perchlorate and perchloric acid, and also two new coordination compounds containing simultaneously nickel perchlorate, acetamide, and perchloric acid: Ni(ClO₄)₂ · 4CH₃CONH₂ · HClO₄ and Ni(ClO₄)₂ · 2CH₃CONH₂ · HClO₄.     

A comparative analysis of the solubility diagrams of iodine-water-alkanol ternary systems at 25°C

The solubilities of the components of the iodine-water-propanol (1-C₃H₇OH) ternary system at 25°C and atmospheric pressure were measured for the first time. The solubility diagram of this system is a ternary system diagram with salting out. Iodine stratifies water-propanol mixtures containing 16.2–73.0 wt % alcohol. The solubility of crystalline iodine increases as the content of alcohol in the mixed solvent grows and is maximum in a mixture containing 79.0 wt % alcohol. A comparative analysis of the phase diagrams of the iodine-water-alkanol (ethanol, propanol-1, and propanol-2) systems was performed. The differences between them can likely be explained by an increase in the electron donor ability of the alcohols, which is also in agreement with the enthalpies of solution of the alcohols in water.     

High pressure phase behavior and modeling of CO2–propyl acrylate and CO2–propyl methacrylate systems

High pressure phase behavior are obtained for CO₂–propyl acrylate system at 40, 60, 80, 100 and 120 °C and pressure up to 161 bar and for CO₂–propyl methacrylate systems at 40, 60, 80, 100 and 120 °C and pressure up to 166 bar. The solubility of propyl acrylate and propyl methacrylate for the CO₂–propyl acrylate and CO₂–propyl methacrylate systems increases as the temperature increases at constant pressure. The CO₂–propyl acrylate and CO₂–propyl methacrylate systems have continuous critical mixture curves that exhibit maximums in pressure at temperatures between the critical temperatures of CO₂ and propyl acrylate or propyl methacrylate. The CO₂–propyl acrylate and CO₂–propyl methacrylate systems exhibit type-I phase behavior with a continuous mixture critical curve.The experimental results for CO₂–propyl acrylate and CO₂–propyl methacrylate systems are modeled using both the statistical associating fluid theory (SAFT) and Peng–Robinson equations of state. A good fit of the data are obtained with SAFT using two adjustable parameters for CO₂–propyl acrylate and CO₂–propyl methacrylate systems and Peng–Robinson equation using one and two adjustable parameter for CO₂–propyl acrylate and CO₂–propyl methacrylate system.     

Solubility of gallic acid in liquid mixtures of (ethanol + water) from (293.15 to 318.15) K

The solubility of gallic acid in (water + ethanol) binary solvents was determined from (293.15 to 318.15) K at atmospheric pressure using a thermostatted reactor and UV/vis spectrophotometer analysis. The effects of binary solvents composition and temperature on the solubility were discussed. It was found that gallic acid solubility in (water + ethanol) mixed solvents presents a maximum-solubility effect. Two empirical equations were proposed to correlate the solubility data. The calculated solubilities show good agreement with the experimental data within the studied temperature range. Using the experimentally measured solubilities, the thermodynamic properties of dissolution of the gallic acid such as Gibbs energy (Δ_solG°), molar enthalpy of dissolution (Δ_solH°), and molar entropy of dissolution (Δ_solS°) were calculated.     

Solubility of nonpolar gases in 2,2,2-trifluoroethanol at 25°C and 101.33 kPa partial pressure of gas

Solubility measurements of several nonpolar gases (He, Ne, Ar, Kr, Xe, H₂, N₂, CH₄, C₂H₄, C₂H₆, CF₄, SF₆, and CO₂) in 2,2,2-trifluoroethanol at 25°C and 101.33 kPa partial pressure of gas are reported. Gibbs energy for the solution process at 25°C is evaluated from the experimental values of the solubility of gases expressed as mole fraction. Lennard-Jones 6–12 pair potential parameters for 2,2,2-trifluoroethanol are estimated by using the scaled particle theory (SPT); and experimental solubilities are compared with those calculated from the values of these parameters through the SPT model.     

Solid–liquid equilibria in the NaCl–SrCl2–H2O system at 288.15 K

The phase equilibria in the ternary system NaCl–SrCl₂–H₂O at 288.15 K were studied with the isothermal equilibrium solution method. The phase diagram and refractive index diagram were plotted for this system at 288.15 K. The phase diagram contains one invariant solubility point, two univariant solubility curves, and two crystallization fields of NaCl and SrCl₂ · 6H₂O. The refractive indices of the equilibrium solution change regularly with w(NaCl) increase. The calculated refractive index data are in good agreement with the experimental data. Combining the experimental solubility data of the ternary system, the Pitzer binary parameters for NaCl at 288.15 K and SrCl₂ at 298.15 K, the Pitzer mixing parameters θ_{Na, Sr}, Ψ_{Na, Sr, Cl} and the solubility equilibrium constants Ksp of solid phases existing in the ternary system at 288.15 K were fitted using the Pitzer and Harvie-Weare (HW) models. The mean activity coefficients of sodium chloride and strontium chloride, and the solubilities for the ternary system at 288.15 K were presented. A comparison between the calculated and measured solubilities shows that the predicted data agree well with the experimental results.     

Isothermal vapour–liquid equilibria in the binary and ternary systems consisting of an ionic liquid, 1-propanol and CO2

Vapour–liquid equilibrium measurements for binary and ternary systems containing carbon dioxide, 1-propanol, and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide or 1-ethyl-3-methylimidazolium trifluoromethanesulfonate ionic liquids are presented in this work. The binary CO₂ + 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide system at 313.15 K at pressure range from 2 to 14.4 MPa was examined. The obtained phase envelop shows that even at low pressure of CO₂ the solubility of the gas in the ionic liquid is high. The ternary phase equilibria were studied at 313.15 K and pressures in the range from 9 to 12 MPa. The ternary phase diagrams show that higher CO₂ pressure diminishes the miscibility gap.     

Measurement of mineral solubilities in the ternary systems NaCl−ZnCl<Subscript>2</Subscript>−H<Subscript>2</Subscript>O and MgCl<Subscript>2</Subscript>−ZnCl<Subscript>2</Subscript>−H<Subscript>2</Subscript>O at 373 K

In this work, the solubilities of the salt minerals and the densities of solution in two ternary systems sodium chloride–zinc chloride–water and magnesium chloride–zinc chloride–water were measured at 373 K using an isothermal solution saturation method. Based on the determined equilibrium solubility data and the corresponding equilibrium solid phase, the phase diagrams and density diagrams of the two systems were plotted. The results show that the two ternary systems are complex and the eutectic points, the univariant solubility curves and the solid crystalline phase regions are shown and discussed. The phase diagram of the ternary system NaCl?ZnCl₂?H₂O at 373 K is constituted of two eutectic points, three univariant solubility curves and three solid crystalline phase regions corresponding to NaCl, ZnCl₂ and 2NaCl · ZnCl₂. And the phase diagram of the ternary system MgCl₂?ZnCl₂?H₂O at 373 K includes two eutectic points, three univariant solubility curves and three solid crystalline phase regions corresponding to MgCl₂ · 6H₂O, MgCl₂ · ZnCl₂ · 5H₂O and ZnCl₂. The experimental results were simply discussed.     

Solubility measurement of α-asarone in supercritical carbon dioxide

The solubility of α-asarone in supercritical CO₂ (sc-CO₂) has been measured using the dynamic method. The measurement was conducted in the pressure range from 9.0 to 18.0 MPa at temperature 35–49 °C. The experimental data were correlated using the Chrastil model. The results show that the solubility increases as the pressure rises and decreases as the temperature rises, which is well correlated with the Chrastil model.     

Phase equilibria and critical phenomena in the cesium nitrate–water–pyridine ternary system

The solubilities of components, phase equilibria, and critical phenomena in the cesium nitrate–water–pyridine ternary system are studied in the 5–100°C temperature range by the visual–polythermal method. Cesium nitrate is found to exhibit a salting-out effect at temperatures above 79.9°C causing phase separation in homogeneous water–pyridine solutions. The temperature of formation of the critical monotectic tie line (79.9°C) and the compositions of solutions corresponding to the liquid–liquid critical points at three temperatures are determined. The pyridine distribution coefficients between the aqueous and organic phases of the monotectic state at 85.0, 90.0, and 100.0°C are calculated. Their values demonstrate that salting-out of pyridine from aqueous solutions by cesium nitrate increases at higher temperatures. The plotted isotherms of phase diagrams confirm the fragment of the scheme of topological transformation of the phase diagrams of salt–binary solvent ternary systems with salting-in and salting-out phenomena.     

Measurements and predictions of density and carbon dioxide solubility in binary mixtures of ethanol and n-decane

The solubility of carbon dioxide (CO₂) in binary mixtures of ethanol and n-decane has been measured using an in-house developed pressure-volume-temperature (PVT) apparatus at pressures up to 6 MPa and two different temperatures (303.2 and 323.2 K). Three different binary mixtures of ethanol and n-decane were prepared, and the densities of the prepared mixtures were measured over the studied pressure and temperature ranges. The experimental data of CO₂ solubility in the prepared mixtures and their saturated liquid densities were then reported at each temperature and pressure. The solubility data indicated that the gas solubility reduced as the ethanol mole fraction in the liquid mixture increased. The dissolution of CO₂ in the liquid mixtures resulted in the increase in the saturated liquid densities. The impact of gas dissolution on the saturated liquid densities was more pronounced at the lower temperature and lower ethanol compositions. The experimental solubility and density data were compared with the results of two cubic equations of state (EOSs), Soave–Redlich–Kwong (SRK) and Peng–Robinson (PR). The modeling results demonstrated that both EOSs could predict the solubility data well, while the saturated liquid densities calculated with the PR EOS were much better than those predicted with the SRK EOS.     

Dual mode model for mixed gas permeation of CO2, H2, and N2 through a dry chitosan membrane

Dry chitosan is an excellent candidate for facilitated transport membranes that can be utilized in industrial applications, such as fuel cell operations and other purification processes. This article is the first to report temperature effects on transport properties of CO₂, H₂, and N₂ in a gas mixture typical of such applications. At a feed pressure of 1.5 atm, CO₂ permeabilities increased (0.381–26.1 barrers) at temperatures of 20–150 °C with decreasing CO₂/N₂ (19.7–4.55) and CO₂/H₂ (3.14–1.71) separation factors. The pressure effect on solubilities and permeabilities were fitted to the extended dual mode model and its corresponding mixed gas permeation model. The dual mode and transport parameters, the sorption heats and the activation energies of Henry's and Langmuir's regimes and their pre‐exponential parameters were determined. The Langmuir's capacity constants were utilized to estimate chitosan's glass transition temperature (CO₂: 172 °C, N₂: 175 °C, and H₂: 171 °C). The activation energies of diffusion in the Henry's law and Langmuir regimes were dependent on the collision diameter of the gases. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 2620–2631, 2007