Topological transformation of a phase diagram for the sodium nitrate-water-isopropanol ternary system

Phase equilibria and critical phenomena in the sodium nitrate-water-isopropanol ternary system, where a boundary binary liquid system shows no immiscibility over the entire temperature range of its liquid state, were studied in the range from 5 to 90°C using a visual polythermal method. The formation temperature of a monotectic critical tie-line was determined to be 6.1°C, and the solution compositions corresponding to critical solution points at various temperatures were determined. Isopropanol partition coefficients between the aqueous and organic phases of monotectic equilibrium were calculated for seven temperatures. The isopropanol salting out from aqueous solutions by sodium nitrate was shown to be enhanced by rising temperature. Isothermal phase diagrams of the title system were constructed to verify a fragment of the general scheme of topological transformations of phase diagrams for salt-binary solvent ternary systems with salting out.     

Phase equilibria and critical phenomena in the cesium nitrate-water-diethylamine ternary system

Phase equilibria and critical phenomena in the cesium nitrate-water-diethylamine ternary system were studied by the visual-polythermal method over the temperature range 60–150 °C, where the boundary binary liquid system was characterized by stratification with a lower critical solution temperature (LCST). The introduction of cesium nitrate into the water-diethylamine system decreased the LCST of this system from 146.1 to 69.3°C and lowered the mutual solubility of the components. The diethylamine distribution coefficients between the aqueous and organic phases were calculated for monotectic equilibria at various temperatures. The salting out of diethylamine with cesium nitrate grew stronger as the temperature increased. The conclusion was drawn that the isotherms of the phase states of the system substantiated the generalized scheme of topological transformations of phase diagrams for salt-binary solvent ternary systems with salting out. The salting out effects of cesium and potassium nitrates on the water-diethylamine binary system were compared.     

Phase Equilibria and Critical Phenomena in the Potassium Nitrate-Water-Diethylamine Ternary System

Phase equilibria and critical phenomena in the potassium nitrate—water—diethylamine ternary system were studied by the visual polythermal method over the temperature range 40–150°C. The corresponding boundary binary liquid system was characterized by stratification with the lower critical temperature of solution. The introduction of potassium nitrate into the water—diethylamine system lowered its lower critical temperature of solution from 146.1 to 48.1°C and decreased the mutual solubility of the components. The diethylamine distribution coefficients between the aqueous and organic monotectic equilibrium phases at various temperatures were calculated. The effect of the salting out of diethylamine from aqueous solutions under the action of potassium nitrate was found to strengthen as the temperature increased. The constructed isotherms of the phase states of the system substantiated the generalized topological scheme of the transformation of phase diagrams of salt-binary solvent ternary systems with salting out.     

Topological transformation of the phase diagram for the ternary system cesium nitrate-water-acetonitrile

In the ternary system cesium nitrate-water-acetonitrile, in which liquid-liquid phase separation with an upper critical solution point (UCSP) exists in the liquid binary subsystem, was studied in the range from ?5 to 120°C using visual polythermal analysis. Liquid-liquid phase separation in the ternary system is observed above 96.0°C and below 2.8°C. Acetonitrile distribution coefficients between the aqueous and organic phases of monotectic equilibrium were calculated for various temperatures. Phase isotherms of the system confirm the general scheme of the topological transformation of phase diagrams in salt-binary solvent ternary systems with salting out.     

Topological transformation of the phase diagram of the potassium nitrate-water-<Emphasis Type="Italic">n</Emphasis>-butoxyethanol ternary system

Phase equilibria and critical phenomena in the potassium nitrate-water-n-butoxyethanol ternary system were studied by the visual polythermal method over the temperature range 10–150°C. In this system, the boundary binary liquid system is characterized by the presence of a closed stratification region. The temperature of the formation of a critical tie line of monotectic equilibrium (18.3°C) and solution compositions corresponding to the critical solubility points at various temperatures were determined. The n-butoxyethanol distribution coefficients between the aqueous and organic phases of the monotectic state were calculated at eight temperatures. n-Butoxyethanol salting out from aqueous solutions by potassium nitrate increased as the temperature grew. The generalized scheme of topological transformations of salt-binary solvent ternary system phase diagrams with salting out was substantiated and augmented.     

Topological transformation of the cesium nitrate-water-isopropanol ternary phase diagram

Phase equilibria and critical phenomena in the cesium nitrate-water-isopropanol system, where the liquid binary subsystem does not separate over the entire temperature range of its liquid state, were studied within 70–120°C using visual polythermal analysis. The temperature at which the monotectic critical tie-line appears (79.0°C) and the compositions of the solutions at critical solution points at various temperatures were determined. Isopropanol distribution coefficients between aqueous and organic monotectic phases were calculated for five temperatures. The salting out of isopropanol by cesium nitrate from aqueous solutions is enhanced by temperature elevation. The phase isotherms validated a previously reported fragment of the general scheme of the topological transformation of ternary phase diagrams for salt-binary solvent systems with salting out. Original Russian Text ? D.G. Cherkasov, V.F. Kurskii, S.I. Sinegubova, K.K. Il’in, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 6, pp. 1032–1036.     

Phase equilibria and critical phenomena in the potassium perchlorate-water-<Emphasis Type="Italic">n</Emphasis>-butoxyethanol ternary system

Phase equilibria and critical phenomena in the potassium perchlorate-water-n-butoxyethanol ternary system, where the boundary liquid binary system is characterized by the presence of a closed stratification region, were studied by the visual-polythermal method over the temperature range 40–150°C. The temperature of the formation of the critical monotectic equilibrium tie line (141.0°C) and temperature dependences of the compositions of mixtures corresponding to the critical solubility points of the stratification region over the temperature ranges 47.7–130.3 and 141.0–150.0°C were determined. The isotherms of phase states constructed at 10 temperatures were used to reveal the topological transformation of the phase diagram of the ternary system depending on temperature. At low concentrations (up to 5.8 wt %), potassium perchlorate had a salting in action on heterogeneous water-n-butoxyethanol mixtures. The solubility of the salt increased as the temperature grew, and, above 141.0°C, potassium perchlorate had a salting out action. The salting out of n-butoxyethanol from aqueous solutions by potassium perchlorate grew stronger as the temperature increased.     

The salting out action of alkali metal nitrates on the water-diethylamine binary system

The results of a polythermal study of the salting out action of alkali metal (Na, K, and Cs) nitrates on the water-diethylamine binary system characterized by stratification with a lower critical solution point (LCSP) were comparatively analyzed. Alkali metal nitrates experiencing homoselective solvation in aqueousorganic solvents were found to decrease the LCSP of this binary system, that is, have a salting out action. A decrease in the radius of the cation in the series CsNO₃-KNO₃-NaNO₃ decreased the temperature of critical tie line formation in the monotectic state of salt-water-diethylamine ternary systems (69.3, 48.1, and 22.9°C, respectively). In all ternary systems, first and foremost in the system with potassium nitrate, the effect of diethylamine salting out from aqueous solutions grew stronger as the temperature increased. The conclusion was drawn that, among the salts studied, sodium nitrate had the strongest salting out effect at 22.9–88.4°C, and potassium nitrate, at 88.4–150.0°C.     

Topological transformation of the phase diagram of a potassium perchlorate-water-tetrahydrofuran ternary system in the temperature range of 40 to 140°C

Phase equilibria and critical phenomena in a potassium perchlorate-water-tetrahydrofuran ternary system are studied by visual polythermal means in the range of 40 to 140°C; the solubility diagram of the liquid subsystem is characterized by the presence of isolated binodal curve. The temperature of formation for the critical node of the monotectic state (107.3°C) and the dependences of the composition that corresponds to the critical points of solubility in the delayering field vs. temperature in the ranges of 70.3 to 107.3°C and 137.1 to 140.2°C are determined. The topological transformation of the investigated ternary system’s phase diagram upon a change in temperature is studied using isothermal sections of the system’s temperature concentration prism, plotted at nine temperatures. It is found that potassium perchlorate has only a salting-in effect on mixtures of water and tetrahydrofuran at temperatures below 107.3°C; at higher temperatures, it has both a salting-in and a salting-out effect, depending on its concentration and the composition of mixed solvent. It is shown that potassium perchlorate’s effect of salting tetrahydrofuran out of aqueous solutions grows slightly with an increase in temperature.     

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.     

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.     

Binary versus ternary interactions in a completely miscible three‐polymer blend system: Poly(ϵ‐caprolactone) with two different methacrylic polymers

A truly miscible ternary miscible blend consisting of poly(?‐caprolactone) (PCL), poly(phenyl methacrylate), and poly(benzyl methacrylate) (PBzMA) was discovered. The three‐polymer blend system was completely miscible within the entire composition range at ambient temperature up to about 150 °C, and ternary phase diagrams at increasing temperatures were characterized and interpreted. A ternary‐interaction model based on the modified Flory–Huggins expression was used to describe the phase diagrams with the individual binary interaction strengths. The model fitted well with the experimental‐phase diagram for the ternary blend system at T = 250 °C, where the binary PCL‐PBzMA blend system is on the critical points of phase separation. Interpretation of discrepancy between the model and experimental at other temperatures was handled with an empirical approach. © 2002 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 40: 747–754, 2002     

Phase equilibria and critical phenomena in a sodium nitrate-water-diethylamine ternary system

The phase equilibria and critical phenomena in a sodium nitrate—water—diethylamine ternary system were studied by the visual polythermal method at 10—150°C, where the frontier binary liquid system is characterized by delamination with the lower critical solution temperature (LCST). The introduction of sodium nitrate into the water—diethylamine system led to a significant decrease (from 146.1 to 22.9°C) in the LCST of the system and the mutual solubility of its components. The coefficients of the distribution of diethylamine between the water and organic phases of the monotectic equilibrium at different temperatures were calculated. The effect of the salting-out of diethylamine by sodium nitrate from aqueous solutions increased with temperature. The constructed isotherms of the phase states of the system confirmed the general scheme of the topological transformation of the phase diagrams of the salt—binary solvent ternary systems with salting-out. The results of the salting-out action of sodi um, potassium, and cesium nitrates on the water—diethylamine binary system were compared.     

Equilibrium of two liquid phases and critical phenomena in a ternary system of cyclohexane-pyridine-acetic acid in the 10–55°C range

A visual polythermal method is used to study the mutual solubility of components and critical phenomena in a ternary system of cyclohexane-pyridine-acetic acid in the 10.0–55.0°C range. It is noted that the isothermal solubility diagrams of the system in the 10.0–52.5°C range is characterized by the occurrence of a closed separation region. A temperature dependence of the mixture composition, which corresponds to the critical point of solubility, is determined. It is found that with the increase in the temperature a two-liquid phase region disappears through a non-critical point.     

Phase behavior of polystyrene–polyisoprene–toluene systems in the temperature range 15–45°c

The phase behavior of narrow molecular weight distribution samples of polystyrene and polyisoprene in the presence of toluene was investigated by means of gel permeation chromatography. Equilibrium phase diagrams, tie lines, and critical points for a number of partially miscible polystyrene-polyisoprene-toluene systems were generated at 15 and 30°C and 1 atm pressure. The data were combined with previously reported results at 45°C. Using the experimentally determined phase compositions along with literature values of the polymer–solvent interaction parameters, the polymer–polymer interaction parameters were evaluated using the Flory–Huggins theory. The influence of temperature, polymer molecular weight, and polymer–solvant interaction parameters on the size, shape, and location of the equilibrium phase curve, the location of the critical point, and the polymer–polymer interaction parameter was studied.     

Topological transformation of the phase diagram of the lithium nitrate-water-acetonitrile ternary system within the range of −20 to 50°C

Phase equilibria and critical phenomena in the lithium nitrate-water-acetonitrile ternary system were studied by a visual polythermal method within the range of ?20 to 50°C. In this ternary system, the constituent liquid binary system is characterized by phase separation with an upper critical solution temperature. It was found that the ternary system undergoes phase separation at temperatures below 0.7°C. In the phase diagram within the range of ?1.1 to 0.7°C, a closed phase separation region with two critical points was revealed. The temperature of the formation of the critical tie line of the monotectic state the solid phase of which is the crystalline hydrate LiNO₃ · 3H₂O was determined (?18.7°C). Depending on the concentration, lithium nitrate has both salting-in and salting-out effect on aqueous acetonitrile mixtures. The plotted isothermal sections of the temperature-concentration prism of the system at fifteen temperatures showed the pattern of the topological transformation of its phase diagram with varying temperature.     

Phase equilibria in the iodine-potassium iodide-water-propanol-2 four-component system

Isothermal-isobaric sections of the phase diagram of the iodine-potassium iodide-water-propanol-2 (2-C₃H₇OH) four-component system were studied at 25°C and atmospheric pressure. In all sections, threephase eutonic equilibria were observed with potassium iodide and crystalline iodine as solid phases. Potassium iodide was a iodine salting in agent in sections containing 15 and 25 wt % propanol-2 and a salting out agent in the section with 50 wt % alcohol. H₂O-2-C₃H₇OH (85: 15 and 75: 25 wt %) mixed solvent compositions showed a higher ability to dissolve iodine than mixture components.     

Liquid-solid equilibrium for the NaCl-NaHCO3-Na2CO3-H2O system at 45°C. Validation of mixed solvent electrolyte model

The main objective of this work was to verify the mixed solvent electrolyte (MSE) thermodynamic model for the prediction of the liquid-solid equilibrium in the soda system. The full quaternary system NaCl-NaHCO₃-Na₂CO₃-H₂O and its three subsystems were considered. Validation of the thermodynamic model was based on experimental data from literature. Phase diagrams for the soda system are plotted for isotherms of 45°C. Good agreement of the MSE results with those from experiments was found at 45°C. Similar phase diagrams for other temperature levels can be constructed based on the validated MSE model.     

UCST behavior in blend systems of isotactic polystyrene/poly(4-methyl styrene) in comparison with atactic polystyrene/poly(4-methyl styrene)

Blends of poly(4-methylstyrene) (P4MS) with polystyrene (iPS) exhibit an upper critical solution temperature (UCST) at ca. 270 °C. The overall phase behavior and trend of variation in the phase diagrams for the iPS/P4MS blend system with respect to molecular weights of iPS is similar to an earlier studied blend system of atactic PS with P4MS. This suggests that the crystal phase-related tacticity and crystallinity in iPS does not influence the amorphous phase behavior and UCST behavior of the polymer mixtures. A model based on a modified Flory-Huggins expression for binary interactions was constructed to describe the UCST-type behavior of the iPS/P4MS blend and to compare the qualitative effects of molecular weights on iPS/P4MS blend vs. atactic PS/P4MS systems.     

Phase diagrams for the binary systems CaCl2-KCl and CaCl2-CaCrO4

Phase diagrams have been determined using differential thermal analysis for the binary systems CaCl₂-KCl and CaCl₂-CaCrO₄. CaCl₂-KCl phase diagrams have been previously reported but results were not consistent. No prior studies have been reported for the CaCl₂-CaCrO₄ system. In the CaCl₂-KCl binary system two eutectics have been located at 24.0 mole % KCl (m.p. 615°C) and 74.3 mole % KCl (m.p. 594°C). A double salt of composition CaKCl3 melting congruently at 741°C has been found. The CaCl₂-CaCrO₄ system is a simple eutectic system with the eutectic occurring at 23.4 mole % CaCrO₄ and melting at 660°C.