(Vapour + liquid) equilibria of the {pentafluoroethane (HFC-125) + dimethyl ether (DME)} system

Binary (vapour + liquid) equilibrium data were measured for the {pentafluoroethane (HFC-125) + dimethyl ether (DME)} system at temperatures from (313.15 to 363.15) K. These experiments were carried out with a circulating-type apparatus with on-line gas chromatography. The experimental data were correlated well by the Peng-Robinson Stryjek-Vera equation of state using the Wong-Sandler mixing rules.     

Vapour pressure and excess Gibbs energy of binary 1,2-dichloroethane + cyclohexanone,chloroform + cyclopentanone and chloroform + cyclohexanone mixtures at temperatures from 298.15 to 318.15 K

The vapour pressures of the binary systems 1,2-dichloroethane + cyclohexanone, chloroform + cyclopentanone and chloroform + cyclohexanone mixtures were measured at temperatures between 298.15 and 318.15 K. The vapour pressures vs. liquid phase composition data for three isotherms have been used to calculate the activity coefficients of the two components and the excess molar Gibbs energies, G^E, for these mixtures, using Barker's method. Redlich–Kister, Wilson, NRTL and UNIQUAC equations, taking into account the vapour phase imperfection in terms of the 2-nd virial coefficient, have represented the G^E values. No significant difference between G^E values obtained with these equations has been observed. Our data on vapour–liquid equilibria (VLE) and excess properties of the studied systems are examined in terms of the DISQUAC and modified UNIFAC (Dortmund) predictive group contributions models.     

VLE of CO2 + glycerol + (ethanol or 1-propanol or 1-butanol)

Vapour-liquid equilibrium of CO₂ + [0.00871 glycerol + 0.99129 (ethanol or 1-propanol or 1-butanol)] mixtures was measured at the temperatures of 313.15 K and 333.15 K, and close to the critical line, at pressures up to 12 MPa. On the liquid side, the bubble points measured for these ternary mixtures follow closely the behaviour of VLE reported by several authors for the corresponding binary mixtures without glycerol. On the vapour side, however, dew points for the ternary mixtures deviate significantly from VLE results for the binaries. A correlation of the results obtained for the CO₂ + glycerol + ethanol mixture with the Peng-Robinson equation of state, admitting quasi-binary behaviour, equally yields good agreement on the liquid side, and significant deviations on the vapour side.     

Liquid density of 1-butanol at pressures up to 140 MPa and from 293.15 K to 403.15 K

This work reports new density data (178 points) of 1-butanol at twelve temperatures between 293.15 and 403.15 K (every 10 K), and fifteen pressures from 0.1 up to 140 MPa (every 10 MPa). An Anton Paar vibrating tube densimeter, calibrated with an uncertainty of ±0.5 kg m⁻³ was used to perform these measurements. The experimental density data were fitted with the Tait-like equation with low standard deviations. In addition, the isobaric thermal expansivity and the isothermal compressibility have been derived from the Tait-like equation.     

Fluid phase equilibria in the binary system trifluoromethane + 1-phenyloctane

Vapour–liquid, liquid–liquid and liquid–liquid–vapour equilibria in the binary system consisting of trifluoromethane (refrigerant R23) and 1-phenyloctane were determined in the temperature range T = 250–400 K and at pressures up to 15 MPa. The experiments were carried using a Cailletet apparatus according to the synthetic method. The investigated system exhibits type III phase behaviour according to the classification of van Konynenburg and Scott. Modelling of the equilibrium data was done with the Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK) equations of state coupled with classical van der Waals mixing rules. In order to predict the global phase behaviour of the system, one single set of binary parameters was used. The topology of the phase behaviour was correctly reproduced.     

Phase behavior of the system hyperbranched polyglycerol + methanol + carbon dioxide

Phase equilibrium data have been measured for the ternary system hyperbranched polyglycerol + methanol + carbon dioxide at temperatures of 313–450 K and pressures up to 13.5 MPa. Phase changes were determined according to a synthetic method using the Cailletet setup. At elevated temperatures the system shows a liquid–liquid–vapor region with lower solution temperatures. Besides the vapor–liquid and liquid–liquid equilibria, the vapor–liquid to vapor–liquid–liquid and vapor–liquid–liquid to liquid–liquid phase boundaries are reported at different polymer molar masses and can serve as test sets for thermodynamic models. A distinct influence of the polymer molar mass on the vapor–liquid equilibrium can be noticed and indicates the existence of structural effects due to the polymer branching. Modeling the systems with the PCP-SAFT equation of state confirms these findings.     

Isothermal vapor-liquid equilibria for methanol and 2,3-dimethyl-2-butene at 343.15 K, 353.15 K, 363.15 K, 373.15 K

Isothermal vapor-liquid equilibrium (VLE) data were measured for the binary system methanol and 2,3-dimethyl-2-butene at 343.15 K, 353.15 K, 363.15 K, 373.15 K, respectively. The measurements were carried out in a novel recirculation equilibrium equipment. Three activity coefficient models including Wilson, NRTL and UNIQUAC, as well as the Soave-Redlich-Kwong equation of state were used to correlate the experimental data. The correlation results showed that a good consistency between the experimental data and the Wilson model can be achieved.     

Isobaric (vapour + liquid) equilibrium for (2-propanol + water + ammonium thiocyanate): Fitting the data by an empirical equation

Isobaric (vapour + liquid) equilibrium (VLE) data for {2-propanol (1) + water (2) + ammonium thiocyanate (3)} were obtained at 101.3 kPa experimentally. An all-glass Fischer-Labodest type still capable of handling pressures from (0.25 to 400) kPa and temperatures up to 523.15 K was used. (Vapour + liquid) equilibrium data of (2-propanol + water) were also obtained at 101.3 kPa experimentally. An equation is proposed to fit the data of salt-containing systems using dimensionless groups called relative ratio. The proposed model was also tested for the salt-containing systems given from the literature.     

Isothermal vapor-liquid equilibrium at T = 333.15 K and excess volumes and molar refractivity deviation at T = 298.15 K for the ternary mixtures {di-methyl carbonate (DMC) + ethanol + benzene} and {DMC + ethanol + toluene}

Isothermal vapor-liquid equilibrium data at 333.15 K are reported for the ternary systems {di-methyl carbonate (DMC) + ethanol + benzene} and {DMC + ethanol + toluene} as determined with headspace gas chromatography. The experimental ternary vapor-liquid equilibrium (VLE) data were correlated with different activity coefficient models. The excess volume (V^E) and deviations in molar refractivity (ΔR) data are reported for the binary systems {DMC + benzene} and {DMC + toluene} and also for the ternary systems {DMC + ethanol + benzene} and {DMC + ethanol + toluene} at 298.15 K. These V^E and ΔR data were correlated with the Redlich-Kister equation for binary systems and the Cibulka equation for ternary systems.     

(Vapour + liquid) equilibrium in (N,N-dimethylacetamide + methanol + water) at the temperature 313.15 K

Total vapour pressures, measured at the temperature 313.15 K, are reported for the ternary mixture (N,N-dimethylacetamide + methanol + water), and for binary constituents (N,N-dimethylacetamide + methanol) and (N,N-dimethylacetamide + water). The present results are compared with previously obtained data for binary mixtures (amide + water) and (amide + methanol), where amide=N-methylformamide, N,N-dimethylformamide, N-methyl-acetamide, 2-pyrrolidinone and N-methylpyrrolidinone. Moreover, it was found that excess Gibbs free energy of mixing for binary mixtures varies roughly linearly with the molar volume of amide.     

Isothermal vapor–liquid equilibrium at 303.15 K and excess molar volumes at 298.15 K for the ternary system of propyl vinyl ether + 1-propanol + 2,2,4-trimethyl-pentane and its binary sub-systems

Isothermal vapor–liquid equilibrium data determined by the static method at 303.15 K are reported for the binary systems propyl vinyl ether + 1-propanol, 1-propanol + 2,2,4-trimethylpentane and propyl vinyl ether + 2,2,4-trimethylpentane and also for the ternary system propyl vinyl ether + 1-propanol + 2,2,4-trimethyl-pentane. Additionally, new excess volume data are reported for the same systems at 298.15 K. The experimental binary and ternary vapor–liquid equilibrium data were correlated with different G^E models and excess molar volume data were correlated with the Redlich–Kister equation for the binary systems and the Cibulka equation for the ternary system, respectively.     

The Solubility of ammonia in ethanol between 277.35 K and 328.15 K

The solubility of ammonia in ethanol has been measured by a static vapor-liquid equilibrium method. The total pressure ranges up to about 0.72 MPa. The temperature amounts to 277.35, 288.65, 298.15, 308.75, 318.25 and 328.15 K. The experimental results are used to determine Henry's law constant. From their variation with temperature, the average absolute relative deviation of the Henry's law constant from appropriate smoothing equation is 4.42%.     

Phase equilibria of (water + levulinic acid + dibasic esters) ternary systems

Liquid–liquid equilibrium (LLE) data of the solubility (binodal) curves and tie-line end compositions were examined for mixtures of {(water (1) + levulinic acid (2) + dimethyl succinate or dimethyl glutarate or dimethyl adipate (3)} at 298.15 K and 101.3 ± 0.7 kPa. The reliability of the experimental tie-line data was confirmed by using the Othmer–Tobias correlation. The LLE data of the ternary systems were predicted by UNIFAC method. The LLE data were correlated fairly well with UNIQUAC and NRTL models, indicating the reliability of the UNIQUAC and NRTL equations for these ternary systems. The best results were achieved with the NRTL equation, using non-randomness parameter (α = 0.3) for the correlation. Distribution coefficients and separation factors were measured to evaluate the extracting capability of the solvents.     

High-pressure phase behaviour of binary (CO2 + nicotine) and ternary (CO2 + nicotine + solanesol) mixtures

This work paper presents vapour–liquid equilibrium (VLE) data for binary (CO₂ + nicotine) and ternary (CO₂ + nicotine + solanesol) mixtures, at 313.2 K and 6, 8 and 15 MPa. The (CO₂ + nicotine) system exhibits three phases (L₁L₂V) in equilibrium at 8.37 MPa. It is estimated that this system most likely follows the type-III phase behaviour. In the ternary system, the presence of solanesol in the vapour phase was detected only at the pressure of 15 MPa. At this pressure, partition coefficients and separation factors for solanesol/nicotine were calculated for different initial nicotine/solanesol compositions and a strong influence of composition was found. The results were modelled using the Peng–Robinson equation of state (PR EOS) coupled with the Mathias–Klotz–Prausnitz (MKP) mixing rule (PR–MKP model). Good correlations of the binary data, particularly in the case of the (CO₂ + nicotine) mixture, were obtained. However, the model could not correlate the ternary data.     

Isothermal vapor–liquid equilibrium data for the binary mixture difluoromethane (HFC-32) + ethyl fluoride (HFC-161) over a temperature range from 253.15 K to 303.15 K

Isothermal vapor–liquid equilibrium data of difluoromethane (HFC-32) + ethyl fluoride (HFC-161) mixture in the range of temperatures from 253.15 K to 303.15 K have been measured in the wide range of compositions. The experimental method used for this work is the single-cycle type. Using Peng–Robinson (PR) equation of state, combined with the first Modified Huron-Vidal (MHV1) mixing rule and Wilson model, the vapor–liquid equilibrium data are correlated. The correlation results have a good agreement with the experiment results. The average absolute vapor composition deviation is within 0.0125, and its largest absolute deviation of the vapor composition is 0.0568; the average relative pressure deviation is within 0.76% and its largest relative pressure deviation is 2.87%. In addition, the results reveal that there is no azeotrope in the binary system, and their temperature glides are small.     

Azeotropic behaviour of (benzene + cyclohexane + chlorobenzene) ternary mixture using chlorobenzene as entrainer at 101.3 kPa

In this paper, the azeotropic behaviour of the (benzene + cyclohexane + chlorobenzene) ternary mixture was experimentally investigated with the aim of enhancing the knowledge for the feasible use of chlorobenzene as an entrainer for the azeotropic distillation of the binary azeotrope. Such a study has not been reported in the literature to the best of the authors’ knowledge. (Vapour + liquid) equilibria data for (benzene + cyclohexane + chlorobenzene) at 101.3 kPa were obtained with a Othmer-type ebulliometer. Data were tested and considered thermodynamically consistent. The experimental results showed that this ternary mixture is completely miscible and exhibits an unique binary homogeneous azeotrope, an unstable node at the conditions studied, and the propitious topological characteristics (residual curve map and relative volatility) to be separated. Satisfactory results were obtained for the correlation of equilibrium compositions with the UNIQUAC activity coefficients model and also for prediction with the UNIFAC method. In both cases, low root mean square deviations of the vapour mole fraction and temperature were calculated. The capability of chlorobenzene as a modified distillation agent at atmospheric condition is discussed in terms of the thermodynamic topological analysis. A conceptual distillation scheme with reversed volatility is proposed to separate the azeotropic mixture. In order to reduce the operational cost requirements of the sequence of columns proposed, the range for optimal reflux and the ratio for feed flow conditions were studied.     

(p, Vm, T) measurements of (cyclohexane + nonane) at temperatures from 298.15 K to 328.15 K and at pressures up to 40 MPa

The densities and speeds of sound of (cyclohexane + nonane) were measured at four temperatures from 298.15 K to 328.15 K, and the respective values of excess volumes and adiabatic compressibility were calculated. Thereafter, the densities for the last system were measured at elevated pressures (0.1 to 40) MPa at four temperatures over the range 298.15 K to 328.15 K with a high-pressure apparatus. The high-pressure density data were fitted to the Tait equation and the isothermal compressibilities were calculated with a novel procedure with the aid of this equation. The low- and high-pressure values of calculated from the density data show that the deviations from ideal behaviour in the system decrease slightly as the temperature and pressure are raised. The data were fitted to the fourth-order Redlich-Kister equation, with the maximum likelihood principle being applied for the determination of the adjustable parameters.     

Prediction of vapor-liquid equilibrium data of the system MTBE + methanol + ethanol by PRSV2 EOS

The Stryjek and Vera (1986) [9] modification of Peng-Robinson (PRSV2) equation of state has been applied for modeling vapor-liquid equilibrium of the systems MTBE + methanol, MTBE + ethanol and methanol + ethanol. Binary interaction parameters for mixing rules have been estimated by using experimental data at the atmospheric pressure. The calculated binary interaction parameters were used for predicting azeotropic behavior at high pressure and also for isobaric equilibrium points which showed an excellent agreement with experimental data. In addition, estimated binary interaction parameters for binary systems were used for ternary system (MTBE + methanol + ethanol). The predictions deviated only slightly from the experimental data. The results show PRSV2 can be used for VLE prediction of polar systems.     

Methane and carbon dioxide solubility in 1,2-propylene glycol at temperatures ranging from 303 to 423 K and pressures up to 12 MPa

This work reports solubility data of methane and carbon dioxide in 1,2-propylene glycol and the Henry's law constant of each solute in the studied solvent at saturation pressure. The measurements were performed at 303, 323, 373, 398 and 423.15 K and pressures up to 4.5 MPa for carbon dioxide solubility and pressures up to 12.1 MPa for methane solubility. The experiments were performed in an autoclave type phase equilibrium apparatus using the total pressure method (synthetic method). All investigated systems show an increase of gas-solubility with the increase of pressure. A decrease of carbon dioxide solubility with the increase of temperature and an increase of methane solubility with the increase of temperature was observed. From the variation of solubility with temperature, partial molar enthalpy and entropy change of the solute for each mixture were calculated.     

Isobaric vapor–liquid equilibria for the quaternary reactive system: Ethanol + water + ethyl lactate + lactic acid at 101.33 kPa

Isobaric vapor–liquid equilibrium (VLE) data of the reactive quaternary system ethanol (1) + water (2) + ethyl lactate (3) + lactic acid (4) have been determined experimentally. Additionally, the reaction equilibrium constant was calculated for each VLE experimental data. The experimental VLE data were correlated using the UNIQUAC equation to describe the chemical and phase equilibria simultaneously. For some of the non-reactive binary systems, UNIQUAC binary interaction parameters were obtained from the literature. The rest of the binary UNIQUAC parameters were obtained by correlating the experimental quaternary VLE data obtained in this work. A maximum pressure azeotrope at high water concentration for the binary reactive system ethyl lactate + water has been calculated.