Solid–liquid phase equilibria for binary mixtures of propellant’s stabilizers

Solid–liquid equilibria for three binary mixtures of N-(2-acetoxyethyl)-p-nitroaniline (1) + 2-nitrodiphenylamine (2), N-(2-acetoxyethyl)-p-nitroaniline (1) + ethyl centralite (2) and N-(2-acetoxyethyl)-p-nitroaniline (1) + methyl centralite (2) have been determined experimentally using differential scanning calorimeter (DSC). Simple eutectic behaviours for these systems have been observed. The experimental results have been correlated by means of NRTL and UNIQUAC equations. The root-mean-square deviations of the solubility temperatures for all measured data vary from 0.61 to 3.32 K and depend on the particular model used. The best solubility correlation has been obtained with the UNIQUAC model.     

Liquid–liquid phase equilibria of the ternary system of water/TBA/2-ethyl-1-hexanol

Liquid–liquid phase equilibria (LLE) for the system of water/tert-butyl alcohol (TBA)/2-ethyl-1-hexanol were investigated experimentally at different temperatures of 298.15, 303.15, 308.15, and 313.15 K. A type 1 liquid–liquid phase diagram was obtained for this ternary system. These results were correlated simultaneously by the UNIQUAC model. The values of the interaction parameters between each pair of components in the system were obtained for the UNIQUAC model using the experimental results. The root mean square deviation (RMSD) between the observed and calculated mole percents was 2.58%. The mutual solubility of 2-ethyl-1-hexanol and water was also investigated by the addition of TBA at different temperatures.     

Liquid—liquid equilibria of ternary systems of 1-hexene/hexane and extraction solvents

Olefins and paraffins are important basic chemical raw materials with so similar molecular structure and volatility that their separation is a difficult and energy-consuming process. Liquid—liquid equilibrium (LLE) data were determined for ternary systems of: 1-hexene + hexane + solvent at 25°C, 30°C, and 35°C, and N-formylmorpholine (NFM), N-methyl-2-pyrrolidone (NMP), γ-butyrolactone (GBL), and 1-methylimidazole (1-MEI) as the solvents studied. Liquid—liquid equilibrium data for each system were correlated to the NRTL (Non-Random Two Liquid) equation and the interaction parameters presented. The calculated results agree well with the experimental data.     

Liquid—liquid equilibria in water—aliphatic alcohol systems in the presence of sodium chloride

Liquid—liquid equilibria in mixtures of water, propyl or butyl alcohol isomers and sodium chloride have been studied experimentally at 25 °C The solvent behaviour of the various alcohols is discussed. Setschenow constants, calculated from the measured data, are compared with the results of the scaled particle theory.     

Vapor—liquid and vapor—liquid—liquid phase equilibria for binary and ternary systems for nitrogen,ethane and methanol: Experiment and data reduction

Zeck, S. and Knapp, H., 1986. Vapor-liquid and vapor-liquid-liquid phase equilibria for binary and ternary systems of nitrogen, ethane and methanol; experiment and data reduction. Fluid Phase Equilibria, 25: 302–322.VLE and VLLE are investigated for three binary and one ternary system containing N₂, C₂H₆ and CH₃OH in a high-pressure phase equilibrium apparatus with vapor recirculation at temperatures 240 < T < 298 K and pressures 4 < p < 75 bar. Two liquid phases are observed in the systems C₂H₆CH₃OH and N₂CH₃OH. Experimental results are reported and compared with available correlations.     

Liquid–liquid equilibria of polydisperse polymer systems: applicability of continuous thermodynamics

Continuous thermodynamics is a suitable tool for describing the thermodynamic properties of solutions of polydisperse polymers. To represent liquid–liquid equilibria of polydisperse polymer/solvent systems, a continuous distribution function to represent the composition of polydisperse polymers has to be considered. In this study, we calculate the molar mass distributions of both principal phases and conjugate phases, using the extended Flory–Huggins model. The results for various polydisperse polymer systems are compared with experimental data.     

Liquid–liquid equilibria of copolymer mixtures based on an equation of state

Liquid–liquid equilibria of copolymer mixtures were studied by an equation of state (EoS) for chain-like fluids. The equation consists of a reference term for hetero-nuclear hard-sphere chain fluids developed by Hu et al. where the next-to-nearest-neighbor correlations have been taken into account; and a perturbation term from Alder et al.’s square-well attractive potential. The segment parameters, including number of segments, segment diameter and interaction energy between segments, are obtained by fitting pVT data of pure homopolymer. For the case of different species in the same copolymer, the interaction parameters for unlike segment pairs are obtained by fitting pVT data of pure copolymer. For the interaction between segment of homopolymer and different species in copolymer, the parameters are treated as adjustable by fitting liquid–liquid equilibria data. In the latter case, the difference between different species in a copolymer is simply neglected as an approximation. Therefore, in general, only one pair of adjustable interaction parameter is determined from LLE data. To model miscibility maps of copolymer mixtures having two or three kinds of species, the interaction parameters are obtained from the boundary between miscible and immiscible regions. The EoS used in this work can correlate phase behavior including coexistence curves, miscibility windows and miscibility maps.     

Vapor — liquid and vapor — liquid — liquid phase equilibria of binary and ternary systems of nitrogen,ethene and methanol: Experiment and data evaluation

Zeck, S. and Knapp, H., 1986. Vapor—liquid and vapor—liquid—liquid phase equilibria of binary and ternary systems of nitrogen, ethene and methanol: experiment and data evaluation. Fluid Phase Equilibria, 26: 37–58.VLE and VLLE of three binary and one ternary system containing the components N₂, C₂H₄ and CH₃OH are investigated in a high-pressure phase equilibrium apparatus with vapor recirculation at temperatures 240 < T < 298 K and pressures 4 < p < 100 bar. Immiscibilities in the liquid phase are observed in the binary system C₂H₄CH₃OH with a lower critical end point and in the ternary system N₂C₂H₄CH₃OH.The experimental results are reported and compared with the results of other investigators and of available correlations.     

Modelling of high-pressure phase equilibria using the Sako–Wu–Prausnitz equation of state: II. Vapour–liquid equilibria and liquid–liquid equilibria in polyolefin systems

Phase equilibria in binary and ternary polyolefin systems are calculated using the cubic equation of state proposed by Sako–Wu–Prausnitz (SWP). Calculations were done for high-pressure phase equilibria in ethylene/polyethylene (LDPE) systems and for liquid–liquid equilibria (LLE) in systems containing either high-density polyethylene or poly(ethylene-co-propylene). The calculations for the copolymer/solvent systems are compared with those using the SAFT EOS. The two equations of state can describe UCST, LCST as well as U-LCST behaviour with similar accuracy. Whereas, the binary interaction parameter is temperature-independent for SAFT, it is found to be a function of temperature for the SWP model. Moreover, the influence of an inert gas on the LCST of the polyethylene/hexane system is investigated using the SWP EOS. The polydispersity of the different polyethylenes is considered in the phase equilibrium calculations using pseudocomponents chosen by the moments of the experimental molecular weight distributions.     

New calculation method for asymmetric closed-loop liquid—liquid equilibria by lattice decoration

A new calculation method for the binary closed-loop coexistence curves of liquid—liquid equilibria has been developed in terms of lattice decoration and the UNIQUAC equation. Two-step renormalization was performed to evaluate the effective interaction energies of sites and the activities of binary mixtures in the decorated lattice consisting of primary and secondary cells. In application, the model reproduced fairly well temperature-composition diagrams which are asymmetric and closed in a loop or have lower consolute points.     

Liquid–liquid equilibria in ternary systems of linear and cross-linked water-soluble polymers

In this study, ternary liquid–liquid equilibrium data of structurally similar linear and cross-linked polymers have been measured in order to elucidate the significance of mixing and elastic effects in sorption of binary liquid mixtures by cross-linked polymers. Dextran, sodium poly(styrene sulfonate), and sodium poly(acrylate) were used as the linear analogues for Sephadex gels and for strong and weak cation exchange resins. Cloud-point and co-existence curves were measured in water/ethanol and water/2-propanol mixtures at 283–343 K and the results were correlated by using a generalized Flory–Huggins model. The mixing parameters of the linear polymers were used to simulate the sorption data in the cross-linked materials and the effect of cross-links was accounted for by a non-ideal elastic model. Good agreement between the simulated and experimental values is obtained, when the chemical heterogeneity and the incomplete functionalization of the cross-linked materials are taken into account. The influence of temperature on the sorption equilibria in cross-linked polymers is also discussed on the basis of the temperature dependence of the cloud-point data.     

Liquid–liquid equilibria for the ternary system water + tetradecane + 2-butyloxyethanol

Liquid–liquid equilibria of the ternary system water + tetradecane + 2-butyloxyethanol in the temperature range from 298.15 to 338.15 K were investigated at atmospheric pressure. The experimental data correlated well with the UNIQUAC model. For the system with a three-liquid-phase-coexisting region, all the six UNIQUAC interaction parameters can be determined numerically by minimizing the deviation of the compositions of three coexisting liquid phases only.     

Liquid—liquid equilibria for the methanol—toluene—n-octane and methanol—toluene—n-hexane systems at 25°C

Ternary liquid—liquid equilibrium data have been measured for the methanol—toluene—n-octane and the methanol—toluene—n-hexane systems at 25°C. The results have been correlated using a modified Wilson equation.     

Liquid–vapor phase equilibria of three-component systems of propanol-2–propanoic acid esters

The boiling points of solutions of three-component systems formed by propanol-2 and propanoic acid esters are measured at different pressures by means of ebulliometry. The coefficients of the activity of the solutions’ components are measured using Wilson and nonrandom two-liquid (NRTL) equations. The results from calculations are in line with the experimental data.

     

Liquid—liquid equilibria for ternary systems of water—phenol and solvents: new UNIFAC parameters for interactions between the groups ACOH/COOH and prediction

The UNIFAC group-contribution method is used to predict ternary liquid—liquid equilibrium data presented in a recent paper (Alvarez Gonzalez et al.) for the systems water/phenol/benzene, water/phenol/ethylbenzene, water/phenol/nonanoic acid, water/phenol/ethyl acetate, water/phenol/isopropyl acetate, water/phenol/n-butyl acetate, water/phenol/isoamyl acetate and water/phenol/cyclohexyl acetate at 25°C and water/phenol/n-hexyl acetate at 25, 35 and 45°C. New UNIFAC interaction parameters between the groups ACOH/COOH have been obtained.A comparison between the experimental and predicted values is presented.     

Liquid–liquid crystalline phase separation in biomolecular solutions

Liquid–liquid phase separation (LLPS) and liquid crystalline (LC) ordering are ubiquitous phenomena in nature, in a variety of biomolecular solutions. Here, we review instances in DNA, nanocellulose, and other systems, where they occur together, leading to the formation of liquid–liquid crystalline phase separation (LLCPS), and we highlight analogies, differences, recent advances, and open questions. Remarkably, the intrinsic fluid yet ordered nature of LC, combined with the spatial confinement induced by LLPS, leads to peculiar biomolecular compartments suitable for a broad range of applications, ranging from material science to synthetic biology. We argue that tools from the LC field help to address still unexplained processes such as the onset of phase transitions in intracellular biomolecular condensates.     

Liquid—liquid equilibria of the system water + acetic acid + methyl ethyl ketone at several temperatures

This article reports the solubilities and equilibrium data of the ternary mixture water + acetic acid + methyl ethyl ketone at 25, 35 and 45°C, and the equilibrium data of the binary system water + methyl ethyl ketone over the range 20–55°C. NRTL and UNIQUAC equations have been fitted to the experimental data for the ternary system, which are also compared with the values predicted by the UNIFAC method.     

Automated apparatus for the rapid determination of liquid–liquid and solid–liquid phase transitions

An automated apparatus developed for the determination of liquid–liquid and solid–liquid equilibrium temperatures with a resolution of 1 mK and a traceable accuracy of 0.01 K is described. The amount of light transmitted through six sample cells placed in a computer controlled thermostat is recorded at heating or cooling rates from 0.075 to 15 K h⁻¹. The construction does not require expensive optic equipment like lasers, glass fibre optics or photomultipliers, but is based on light emitting diodes (LED) as light sources and light dependent resistors (LDR) or photodiodes as detectors. As shown by the discussed examples, the instrument has a wide range of possible applications from the investigation of simple one-component and binary systems to the study of the complicated phase behavior of surfactant solutions.     

Solid and liquid phase equilibria and solid-hydrate formation in binary mixtures of water with amines

Solid and liquid phase diagrams have been constructed for {water+triethylamine,or+N,N-dimethylformamide(DMF) or+N,N-dimethlacetamide (DMA)} Solid-hydrates form with the empirical formulae N(C2H5)3 3H2O,DMF 3H2O,DMF 2H2O,DMA 3H2O and (DMA)2 3H2O.All are congruently melting except the first which melts incongruently.The solid-hydrate formation is attributed to hydrogen bond.The results are compared with the references