Influence of Temperature on Liquid–Liquid Equilibrium of Methanol + Toluene + Hexane Ternary Systems at Atmospheric Pressure

Phase equilibria of methanol?+?toluene?+?hexane ternary systems at (278.15, 283.15, 288.15 and 293.15) K at atmospheric pressure were investigated. The influence of temperature on the liquid–liquid equilibrium is discussed. All chemicals were quantified using gas chromatograph with a thermal conductivity detector coupled to a ChemStation and nitrogen as gas carrier, their mass fractions were higher than 0.999. From literature are found two articles from the same system at different temperatures studied here. Experimental data are compared with literature values. Values calculated using the NRTL and UNIQUAC equations are compared with the experimental data and it is found that the UNIQUAC equation fitted the experimental data better than the NRTL model for this ternary system.     

Vapor–liquid equilibria for nitrogen with 2-propanol, 2-butanol,or 2-pentanol binary systems

Isothermal vapor–liquid equilibrium (VLE) data were measured for the binary systems of nitrogen with 2-propanol, 2-butanol, or 2-pentanol at temperatures from 333.15 to 393.15 K and pressure up to 100 bar. Henry's constants of nitrogen in these three sec-alcohols were determined by using the Krichevesky–Ilinskaya equation. The experimental VLE data were also correlated by the Peng–Robinson and the Patel–Teja equations of state with various mixing rules.     

Vapour-liquid equilibrium at high pressure in the system containing carbon dioxide and propyl acetate

Wagner Z.: Vapour-liquid equilibrium at high pressure in the system containing carbon dioxide and propyl acetate.

Vapour-liquid equilibrium data in the carbon dioxide---propyl acetate system were measured isothermally at 303.15 K, 313.15 K, and 323.15 K at pressures ranging from 2 MPa to 9 MPa. The experimental data were fitted to the Soave-Redlich-Kwong equation of state in the modification of Graboski and Daubert with the mixing rules developed by Kwak and Mansoori. Maximum likelihood procedure was adopted and all variables were assumed to be subject to errors.     

Vapor—liquid equilibria for the binary system 2-methylbutene-2 and 2-methyl-1,3-butadiene at 310.93, 316.48 and 322.04 K

Total pressure, vapor—liquid equilibrium data for the binary system 2-methyl-1,3-butadiene and 2-methylbutene-2 are reported at 310.93, 316.48 and 322.04 K. The experimental uncertainties in measured variables, expressed as standard deviations, are 0.0005 mole fraction, 0.01 K and 0.2% of measured pressure. The coefficients for a modified Wilson solution model are also reported. These coefficients were determined from the experimental data using a general non-linear least-squares technique which accounts for experimental uncertainties in independent and dependent variables. The standard deviations of prediction for temperature-independent coefficients are 0.17% for pressure, 0.001 K for temperature and 0.00001 for mole fraction.     

Vapor–liquid equilibrium of nitrogen in an equimolar hexane + decane mixture at temperatures of 258, 273, and 298 K and pressures to 20 MPa

In this work we present experimental results of P, T, x, y, for the vapor–liquid equilibrium of the ternary system: nitrogen in an equimolar hexane+decane mixture at 258, 273, and 298 K in the range 1.5–20 MPa. The solubility of nitrogen in the liquid mixture of hexane+decane is increased when the pressure is increased; however, a considerable change in the solubility values is not observed as a function of temperature in the range studied. We have correlated the experimental results using the Peng–Robinson equation of state. The standard deviation of the fit shows that the data are well correlated (within the experimental error) in the ranges of pressure and temperature studied.     

Simultaneous measurement of the solubility of nitrogen and carbon dioxide in polystyrene and of the associated polymer swelling

New experimental results for the solubility of nitrogen and carbon dioxide in polystyrene are reported, accompanied by data on the change in volume of the polymer caused by the sorption process. The two phenomena were measured simultaneously with a combined technique, in which the quantity of penetrating fluid introduced into the system was evaluated by pressure‐decay measurements in a calibrated volume, whereas a vibrating‐wire force sensor was employed for weighing the polymer sample during sorption inside of the high‐pressure equilibrium cell. The use of the two techniques was necessary because the effects of swelling and solubility could not be decoupled in a single gravimetric or pressure‐decay measurement. The sorption of nitrogen in polystyrene was studied along three isotherms from 313 to 353 K at pressures up to 70 MPa. The sorption of carbon dioxide was measured along four isotherms from 338 to 402 K up to 45 MPa. The results are compared with values from the literature when possible, although our data extend significantly the pressure ranges of the latter. The uncertainties affecting our measurements with nitrogen are 1 mg of N₂/g of polystyrene in solubility and 0.1% of the volume of the polymer. For carbon dioxide, the uncertainties are 5 mg of N₂/g of polystyrene and 0.5% respectively, carbon dioxide being about 1 order of magnitude more soluble than nitrogen. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2063–2070, 2001     

Measurement and thermodynamic model study on equilibrium solubility in the ternary system KCl-KBr-H2O at 323.15 K

The solubilities and the refractive indices of the KCl-KBr-H₂O system at 323.15 K were studied with the isothermal dissolution method. The phase diagram and refractive index diagram were plotted for this system at 323.15 K. There is only one crystallization field of the solid solution K(Cl, Br). The system belongs to the solid solution type. The refractive indices of the equilibrium solution varies regularly with w(KCl) increasing. The calculated refractive index data are in good agreement with the experimental data. The parameter Ψ_{K, Cl, Br} at 323.15 K was fitted using the measured solubility data in this study. The equilibrium constant equation for the equilibrium solids at 323.15 K were obtained using the different Pitzer parameters from the literature or this work with a method using the activity product constant. The calculated solubilities agree well with experimental values.     

Liquid–liquid equilibrium of the ternary system water + acetic acid + sec-butyl acetate

Experimental liquid–liquid equilibrium (LLE) of the water–acetic acid–sec-butyl acetate ternary system was investigated at 298.15, 303.15, 308.15 and 313.15 K and at atmospheric pressure. Separation factors were also evaluated for the immiscibility region. The NRTL and UNIQUAC models were applied to fit the experimental data for the ternary system. The binary interaction parameters obtained from both models were found to be successfully correlated with the equilibrium compositions. The UNIFAC group contribution method was employed to predict the observed ternary LLE data. It was found that four types of the UNIFAC model (UNIFAC, UNIFAC-LL, UNIFAC-DMD, and UNIFAC-LBY) did not provide a good prediction of the LLE data for this ternary system.     

Vapor–liquid equilibrium of methane and methane + nitrogen and an equimolar hexane + decane mixture under isothermal conditions

Experimental vapor–liquid equilibrium data of the ternary system composed of methane and an equimolar hexane + decane mixture are reported. The experimental measurements were carried out under isothermal conditions at 258, 273, and 298 K in the pressure range 1–19 MPa. Also, experimental vapor–liquid measurements were carried out for the quaternary system methane + nitrogen and an equimolar hexane + decane mixture, at 258 K in the range 3.5–12 MPa. The results for the ternary system show that the solubility of methane in the equimolar mixture of alkanes increases when the pressure is increased at constant temperature and it increases as the temperature decreases in the whole pressure range studied. For the quaternary system with a constant amount of nitrogen, the solubility of methane in the liquid phase increases as the pressure increases at the studied temperature. The experimental results for the ternary system were satisfactorily correlated with the Peng–Robinson equation of state in the ranges of pressure and temperature studied. The equation of state was used to predict the behavior of the quaternary system using binary interaction parameters. The applicability of the principle of congruence was corroborated by comparing the vapor–liquid behavior of methane in the equimolar hexane + decane mixture with that in pure octane, at the three temperatures studied in this work.     

二氧化碳和碳酸二甲酯二元体系的气液相平衡数据

实验测定了二氧化碳和碳酸二甲酯(DMC)二元体系的高压气液相平衡数据. 实验温度为333.0 到393.0 K, 实验压力为3.98 到13.75 MPa. 应用Peng-Robison (PR)立方形状态方程和van der Waals-1 混合规则对实验数据进行了关联计算, 同时得到了二元相互作用参数. 计算结果与实验数据具有很好的一致性.     

Isothermal vapour–liquid equilibria in the ternary system tert-butyl methyl ether + tert-butanol + 2,2,4-trimethylpentane and the three binary subsystems

Vapour–liquid equilibrium data are reported for the ternary tert-butyl methyl ether+tert-butanol+2,2,4-trimethylpentane and the three binary tert-butyl methyl ether+tert-butanol, tert-butyl methyl ether+2,2,4-trimethylpentane, tert-butanol+2,2,4-trimethylpentane subsystems. The data were measured isothermally at 318.13, 328.20, and 339.28 K covering pressure range 15–100 kPa. Azeotropic data are presented for the tert-butanol+2,2,4-trimethylpentane system. Molar excess volumes at 298.15 K are given for the three binary systems. The binary vapour–liquid equilibrium data were correlated using Wilson, NRTL, and Redlich–Kister equations; the parameters obtained were used for calculation of phase behaviour in ternary system and for subsequent comparison with experimental data.     

The equilibrium phase properties of selected naphthenic binary systems: Carbon dioxide-methylcyclohexane,hydrogen sulfide-methylcyclohexane

Vapor and liquid equilibrium phase compositions have been determined at temperatures ranging from 310 to 478 K for two binary systems. Measurements were made at 311.0, 338.9, 394.0, and 477.2 K for the carbon dioxide—methylcyclohexane system and at 310.9, 352.6, 394.3 and 477.6 K for the hydrogen sulfide—methylcyclohexane system. At each temperature, pressures ranged from the vapor pressure of methylcyclohexane to the vapor pressure of hydrogen sulfide, or to a pressure near the critical for the system, whichever was higher. The data were used to calculate equilibrium ratios for each component in the binary system.     

氯仿－苯－正丁醇三元体系加压相平衡研究

本文根据氯仿、苯、正丁醇有关二元体系实测数据统一关联所得的能量参数关联式，用Ｗｉｌｓｏｎ方程对氯仿－苯－正丁醇三元体系在１０１～３０３ｋＰａ压力下的汽液平衡作了预测，并与本工作的实测数据比较，二者符合良好。实验结果表明，这三元体系与氯仿－苯－乙醇体系的汽液相平衡行为具有相似的规律。     

Thermodynamic model of solubility for CO2 in dimethyl sulfoxide

The solubility of CO₂ in dimethyl sulfoxide has been determined from 293.15 K to 313.15 K and partial pressure of CO₂ from 5.56 kPa to 18.2 kPa. Based on the data obtained from the CO₂ solubility experiments, a gas–liquid phase equilibrium model for CO₂–DMSO system was proposed. The average relative deviation between the experimental data of equilibrium partial pressure of CO₂ in DMSO and the corresponding data predicted by the model proposed is 4.85%, it shows that the agreement is satisfactory.     

Isothermal vapour–liquid equilibria in the binary and ternary systems composed of 2-propanol, diisopropyl ether and 1-methoxy-2-propanol

Vapour pressures for 1-methoxy-2-propanol are reported as well as the vapour–liquid equilibrium data in the two binary 2-propanol + 1-methoxy-2-propanol, and diisopropyl ether + 1-methoxy-2-propanol systems, and in the ternary 2-propanol + diisopropyl ether + 1-methoxy-2-propanol system. The data were measured isothermally at 330.00 and 340.00 K covering the pressure range 5–98 kPa. The binary vapour–liquid equilibrium data were correlated using the Wilson, NRTL, and Redlich–Kister equations; resulting parameters were then used for calculation of phase behaviour in the ternary system and for subsequent comparison with experimental data.     

Chemical Equilibrium for the Reacting System Acetic Acid–Ethanol–Ethyl Acetate–Water at 303.15 K, 313.15 K and 323.15 K

The chemical equilibrium (CE) for the quaternary reacting system ethanol–acetic acid–ethyl acetate–water was studied at 303.15, 313.15 and 323.15 K and atmospheric pressure. The CE compositions were determined by gas chromatography and nuclear magnetic resonance analytical methods. The thermodynamic constants of CE at 303.15, 313.15 and 323.15 K were calculated based on the obtained experimental data with the use of the NRTL model.     

Vapor–liquid equilibria and interfacial tensions for the ternary system acetone + 2,2′-oxybis[propane] + cyclohexane and its constituent binary systems

Isobaric vapor–liquid equilibrium data have been measured for the ternary system acetone + 2,2′-oxybis[propane] + cyclohexane, and its constituent binaries at 94 kPa and in the temperature range 324–350 K in a vapor–liquid equilibrium still with circulation of both phases. The dependence of the interfacial tensions of these mixtures on concentration was also determined at atmospheric pressure and 303.15 K, using the maximum bubble pressure technique.From the experimental results, it follows that both the ternary and binary mixtures exhibit positive deviations from ideal behavior and, additionally, azeotropy is present for the binaries that contain acetone. The application of a model-free approach allows conclusions about the reliability of the present vapor–liquid equilibrium data for all the indicated mixtures. Furthermore, the determined interfacial tensions exhibit negative deviation from linear behavior for all the analyzed mixtures, and aneotropy is observed for the acetone + cyclohexane mixture.The vapor–liquid equilibrium data of the binary mixtures were well correlated using the NRTL, Wilson and UNIQUAC equations. In a similar manner, the interfacial tensions of the binary mixtures were smoothed using the Redlich–Kister equation. Scaling of these models to the ternary mixture allows concluding that both the vapor–liquid equilibrium data and the interfacial tensions can be reasonably predicted from binary contributions.     

Vapor pressure of R227ea + ethanol at 343.13 K by molecular simulation

A new molecular model for 1,1,1,2,3,3,3-heptafluoropropane (R227ea) was developed on the basis of quantum chemical calculations and optimized using experimental vapor pressure and bubble density data. In combination with an existing model for ethanol, a molecular model for the binary mixture R227ea + ethanol was defined, using the Lorentz–Berthelot combining rule. It was validated at 283.17 K, where, considering the statistical uncertainties, it agrees to the experimental vapor pressure. The vapor–liquid equilibrium, comprising both bubble line and dew line data, was predicted at 343.13 K by molecular simulation. The Peng–Robinson equation of state fails for this system.     

Vapor–liquid equilibria in the binary system (−)-beta-pinene + (+)-fenchone: Analysis in terms of group contributions models of some binary systems containing terpenoids

Isobaric vapor–liquid equilibrium measurements are reported for the binary system (−)-beta-pinene + (+)-fenchone at the constant pressure of 13.33 kPa in the temperature range from 341.60 K to 393.25 K. The boiling temperatures of the mixtures were also measured at seven constant compositions in the pressure range from 2.56 kPa to 20.80 kPa. The experimental data were found to be thermodynamically consistent. Reduction of the vapor–liquid equilibrium data was carried out by means of the Wilson, NRTL and UNIQUAC equations. Our data on vapor–liquid equilibria for mixtures containing terpenoids are examined in terms of the DISQUAC and modified UNIFAC (Dortmund) group contributions models. Interaction parameters of the DISQUAC model are reported.     

Liquid–liquid equilibria for pseudoternary systems: isooctane–benzene–(methanol + water)

Liquid–liquid equilibrium data are presented for the pseudoternary systems isooctane–benzene–(90 mass% methanol + 10 mass% water) at 298.15 K and isooctane–benzene–(80 mass% methanol + 20 mass% water) at 298.15 and 308.15 K, under atmospheric pressure. The experimental tie-line data obtained define the binodal curve for each one of the studied systems which depending on the amount of water present show type I or type II liquid–liquid phase diagrams. In order to obtain a general view of the effect of water on the partitioning of methanol and hence on the size of the two-phase region we have also determined experimentally ‘isowater’ tolerance curves for the system isooctane–benzene–methanol at 298.15 K, hence the tie-line data were also obtained for the ternary system. The experimental tie-line data for the four systems studied were correlated with the NRTL and UNIQUAC solution models obtaining a very good reproduction of the experimental behaviour.