(Vapor + liquid) phase equilibrium measurements for {trifluoroiodomethane (R13I1) + propane (R290)} from T = (258.150 to 283.150) K

In this paper, the (vapor + liquid) equilibrium data for (R13I1 + R290) were measured by a vapor-recirculation apparatus at temperatures from (258.150 to 283.150) K. The VLE data were correlated by the Peng–Robinson equation of state with two different models, the van der Waals mixing rule, and the Huron–Vidal mixing rule involving the NRTL activity coefficient model. Good agreements were found between the calculated data and the experimental data. The maximum average absolute relative deviation of pressure (AARD p) was 0.48%, while the maximum average absolute deviation of composition (AAD y) was 0.0040. Meanwhile, zeotropic behavior can be found for the measured system in this study. The total combined standard uncertainties for temperature, pressure and composition measurements were ±5 mK, ±0.0005 MPa and ±0.005, respectively.     

(Vapour + liquid) equilibrium data for the azeotropic {1,1-difluoroethane (R152a) + 1,1,2,2-Tetrafluoroethane (R134)} system at various temperatures from (258.150 to 288.150) K

(Vapour + liquid) equilibrium (VLE) data for the {1,1-difluoroethane (R152a) + 1,1,2,2-Tetrafluoroethane (R134)} system were measured at T = (258.150 to 288.150) K. The experiment is based on a static–analytic method. Experimental data were correlated with the Peng–Robinson equation of state (PR EoS) and the Huron–Vidal (HV) mixing rule involving the NRTL activity coefficient model. The results show good agreement with experimental results for the binary system at each temperature. It was found that the system has a negative azeotropic behaviour within the temperature range measured here.     

Isothermal (vapour + liquid) equilibrium for the binary {1,1,2,2-tetrafluoroethane (R134) + propane (R290)} and {1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a)} systems

(Vapour + liquid) equilibrium (VLE) data for the binary systems of {1,1,2,2-tetrafluoroethane (R134) + propane (R290)} and {1,1,2,2-tetrafluoroethane (R134) + isobutane (R600a)} were measured with a recirculation method at the temperatures ranging from (263.15 to 278.15) K and (268.15 to 288.15) K, respectively. All of the data were correlated by the Peng–Robinson (PR) equation of state (EoS) with the Huron–Vidal (HV) mixing rules utilizing the non-random two-liquid (NRTL) activity coefficient model. Good agreement can be found between the experimental data and the correlated results. Azeotropic behaviour can be found at the measured temperature ranges for these two mixtures.     

Experimental measurement of vapor pressures and (vapor + liquid) equilibrium for {1,1,1,2-tetrafluoroethane (R134a) + propane (R290)} by a recirculation apparatus with view windows

The saturated vapor pressures of 1,1,1,2-tetrafluoroethane (R134a) and propane (R290), and the (vapor + liquid) equilibrium (VLE) data at (255.000, 265.000, 275.000, and 285.000) K for the (R134a + R290) system were measured by a recirculation apparatus with view windows. The uncertainty of the temperatures, pressures, and compositions are less than ±5 mK, ±0.0005 MPa, and ±0.005, respectively. The saturated vapor pressures data were correlated by a Wagner type equation and compared with the reference data. The binary VLE data were correlated with the Peng–Robinson equation of state (PR EoS) incorporating the Huron–Vidal (HV) mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model. For mixtures, the maximum average absolute relative deviation of pressure is 0.15%, while the maximum average absolute deviation of vapor phase mole fraction is 0.0045. Azeotropic behavior can be found for the (R134a + R290) system at measured temperatures.     

Liquid viscosity of low-GWP refrigerant mixtures (R32 + R1234yf) and (R125 + R1234yf)

In this work, the viscosity of R1234yf, (R32 + R1234yf), and (R125 + R1234yf) in one-phase liquid was measured. The combined expanded uncertainty of viscosity measurement apparatus of confidence of 0.95 (k = 2) is about 2.0%. The measurements of mixtures containing (30.0, 50.0, and 70.0) wt% R32 or R125 were carried out between T = (283.0 and 323.0) K (at intervals of T = 5 K) and P = (1.58 and 2.74) MPa, with a moving piston viscometer (VISCOpro 1600, accuracy ±1.0%) and a Coriolis flowmeter (Ultramass MKII, accuracy ±0.001 g/ml). The measured data were correlated with a hard-sphere (RSH) method and the Grunberg and Nissan method. The average absolute deviations are (2.2 and 3.3)% for the (R32 + R1234yf) and (R125 + R1234yf) mixtures by RSH method, (2.8 and 1.3)% for the (R32 + R1234yf) and (R125 + R1234yf) mixtures by Grunberg and Nissan method, while (3.5 and 2.4)% for the (R32 + R1234yf) and (R125 + R1234yf) mixtures by RefProp V9.1, respectively.     

Isothermal (vapour + liquid) equilibrium and thermophysical properties for (1-butyl-3-methylimidazolium iodide + 1-butanol) binary system

Experimental isothermal (vapour + liquid) equilibrium (VLE) data are reported for the binary mixture containing 1-butyl-3-methylimidazolium iodide ([bmim]I) + 1-butanol at three temperatures: (353.15, 363.15, and 373.15) K, in the range of 0 to 0.22 liquid mole fraction of [bmim]I. Additionally, refractive index measurements have been performed at three temperatures: (293.15, 298.15 and 308.15) K in the whole composition range. Densities, excess molar volumes, surface tensions and surface tension deviations of the binary mixture were predicted by Lorenz–Lorentz (n_D-ρ) mixing rule. Dielectric permittivities and their deviations were evaluated by known equations. (Vapour + liquid) equilibrium data were correlated with Wilson thermodynamic model while refractive index data with the 3-parameters Redlich–Kister equation by means of maximum likelihood method. For the VLE data, the real vapour phase behaviour by virial equation of state was considered. The studied mixture presents S-shaped abatement from the ideality. Refractive index deviations, surface tension deviations and dielectric permittivity deviations are positive, while excess molar volumes are negative at all temperatures and on whole composition range. The VLE data may be used in separation processes design, and the thermophysical properties as key parameters in specific applications.     

(Vapour + liquid) equilibrium data for the binary system of {trifluoroiodomethane (R13I1) + trans-1, 3, 3, 3-tetrafluoropropene (R1234ze (E))} at various temperatures from (258.150 to 298.150) K

(Vapour + liquid) equilibrium (VLE) data for the binary system of {trifluoroiodomethane (R13I1) + trans-1, 3, 3, 3-tetrafluoropropene (R1234ze (E))} were measured by a static-analytic method within the temperature range of (258.150 to 298.150) K. The experimental data were correlated using the Peng–Robinson equation of state (PR EoS) with the Huron–Vidal (HV) mixing rule involving the NRTL activity coefficient model. The results show good agreement with experimental values for the binary system at each temperature point. The maximum average absolute relative deviation of pressure is 0.28%, while the maximum average absolute deviation of vapour phase mole fraction is 0.0025. Obviously azeotropic behaviour can be found for the measured temperature range here.     

Modification of Peng Robinson EOS for modelling (vapour + liquid) equilibria with electrolyte solutions

A modification of the extended Peng–Robinson equation of state (PR-EOS) is presented to describe the (vapour + liquid) equilibria of systems containing water and salts. The modification employs three additional terms including a Born term, a Margules term and two terms separately used for estimation of the long-range electrostatic interactions (the Debye–Huckel (DH) or the mean spherical approximation (MSA) terms). Effects of two mixing rules, first, the Panagiotopoulos and Reid mixing rule (PR) and, second, the Kwak and Mansoori mixing rule (KM), on the final values of VLE calculations are also investigated. The results show that the KM mixing rule is more appropriate than the PR mixing rule. The proposed equation of state is used to calculate the (vapour + liquid) equilibrium (VLE) of the systems containing (water + sodium sulphate + carbon dioxide) and (water + sodium chloride + carbon dioxide) at high pressure. The comparison of calculated results with the experimental data shows that a combination of KM mixing rule with the DH term results a more accurate VLE values.     

Vapor–liquid equilibria in the ternary system isobutyl alcohol + isobutyl acetate + butyl propionate and the binary systems isobutyl alcohol + butyl propionate,isobutyl acetate + butyl propionate at 101.3 kPa

Consistent vapor–liquid equilibrium (VLE) data at 101.3 kPa have been determined for the ternary system isobutyl alcohol (IBA) + isobutyl acetate (IBAc) + butyl propionate (BUP) and two constituent binary systems: IBA + BUP and IBAc + BUP. The IBA + BUP system show lightly positive deviation from Raoult's law and IBAc + BUP system exhibits no deviation from ideal behaviour. The activity coefficients of the solutions were correlated with its composition by the Wilson, NRTL, UNIQUAC models. The ternary system is very well predicted from binary interaction parameters. BUP eliminates the IBA–IBAc binary azeotrope. The change of phase equilibria behaviour is significant therefore this solvent seems to be an effective agent for that azeotrope mixture separation. In fact, the mean relative volatility on a solvent free basis is 1.8.The binary VLE data measured in the present study passed the thermodynamic consistency test of Fredenslund et al. [A. Fredenslund, J. Gmehling, P. Rasmussen, Vapor–Liquid Equilibria Using UNIFAC, A Group Contribution Method, Elsevier, Amsterdam, 1977], and were correlated by the Wilson, NRTL and UNIQUAC models to relate activity coefficients with mole fractions. The VLE data obtained for the ternary system passed both the Wisniak L–W [J. Wisniak, Ind. Eng. Chem. Res. 32 (1993) 1531–1533] and McDermott–Ellis [C. McDermott, S.R. Ellis, Chem. Eng. Sci. 20 (1965) 293–296] consistency test. The parameters obtained from binary data were utilized directly to predict the phase behaviour of the ternary system. The results showed an excellent agreement with experimental values.     

Isobaric (vapor + liquid) equilibrium data for the binary system methanol + 2-butyl alcohol and the quaternary system methyl acetate + methanol + 2-butyl alcohol + 2-butyl acetate at P = 101.33 kPa

In this paper, isobaric (vapor + liquid) equilibrium (VLE) data for the binary system methanol + 2-butyl alcohol and the quaternary system methyl acetate + methanol + 2-butyl alcohol + 2-butyl acetate were determined at P = 101.33 kPa in a modified Rose still. The binary VLE data were found to be thermodynamic consistency by the Herrington method. The VLE data for the binary system were correlated by the Wilson and NRTL equations respectively, which were used to predict the VLE data of the quaternary system. The results showed that the Wilson and NRTL models matched well with the (vapor + liquid) phase equilibrium data. The deviations for the vapor-phase compositions and the equilibrium temperatures are reasonably small and the models are both suitable for these systems.     

Vapour–liquid equilibrium measurements and correlation for the pentafluoroethane (R125) + n-butane (R600) system

Mixtures formed by hydrocarbons (HC) and hydrofluorocarbons (HFC) are considered promising possible substitutes for the chlorinated refrigerants and for HFC with high global warming potential (GWP). Following our studies on this kind of systems, vapour–liquid equilibria (VLE) experimental data for the R125 + R600 system were measured at temperatures 278.15 and 298.15 K by means of a static analytical method, with preliminary recirculation of the mixture to get a faster equilibrium. The composition of both phases in equilibrium was measured by a gas-chromatographic method. In the experimental temperature range, the system shows a strong positive deviation from the Raoult's law, even if it does not present an azeotropic composition. The VLE data were correlated by different equations of state involving various mixing rules, enabling a comparable analysis of their correlating ability of strongly non-ideal systems.     

Vapor–liquid equilibrium measurements and correlations for an azeotropic system of ethane + hexafluoroethane

The research on the isothermal vapor–liquid phase behavior for the ethane (R170) + hexafluoroethane (R116) system is presented in this paper. The vapor–liquid equilibrium (VLE) data were measured at four temperatures 189.31, 192.63, 247.63 and 252.80 K with an apparatus based on recirculation method. The experimental results were correlated with the Peng–Robinson equation of state using two types of mixing rules, the Panagiotopoulos–Reid mixing rule and the Huron–Vidal mixing rule involving the NRTL model. The calculated data using the regressed parameters were compared with the previous measured results, and good agreements can be observed.     

(Vapor + liquid) equilibrium data for (carbon dioxide + 1,1-difluoroethane) system at temperatures from (258 to 343) K and pressures up to about 8 MPa

Accurate thermo-physical data are of utmost interest for the development of new efficient refrigeration systems. Carbon dioxide (R744) and 1,1-difluoroethane (R152a) are addressed here. Isothermal (vapor + liquid) equilibrium data are reported herein for (R744 + R152a) binary system in the (258–343) K temperature range and in the (0.14 to 7.65) MPa pressure range. A reliable “static-analytic” method taking advantage of two online ROLSI? micro capillary samplers is used for all thermodynamic measurements. The data are correlated using our in-house ThermoSoft thermodynamic model using the Peng–Robinson equation of state, the Mathias–Copeman alpha function, the Wong–Sandler mixing rules, and the NRTL model.     

High-pressure phase equilibria in the (carbon dioxide + 1-hexanol) system

(Vapour + liquid) equilibria (VLE) and (vapour + liquid + liquid) equilibria (VLLE) data for the (carbon dioxide + 1-hexanol) system were measured at (293.15, 303.15, 313.15, 333.15, and 353.15) K. Phase behaviour measurements were made in a high-pressure visual cell with variable volume, based on the static-analytic method. The pressure range under investigation was between (0.6 and 14.49) MPa. The Soave–Redlich–Kwong (SRK) equation of state (EOS) with classical van der Waals mixing rules (two-parameters conventional mixing rule, 2PCMR), was used in a semi-predictive approach, in order to represent the complex phase behaviour (critical curve, LLV line, isothermal VLE, LLE, and VLLE) of the system. The topology of phase behaviour is reasonably well predicted.     

Isobaric (vapour + liquid) equilibria data for the binary systems {1,2-dichloroethane (1) + toluene (2)} and {1,2-dichloroethane (1) + acetic acid (2)} at atmospheric pressure

In this study for two binary systems {1,2-dichloroethane (1) + toluene (2)} and {1,2- dichloroethane (1) + acetic acid (2)}, the isobaric (vapour + liquid) equilibrium (VLE) data have been measured at atmospheric pressure. An all-glass Fischer–Labodest type capable of handling pressures from (0.25 to 400) kPa and temperatures up to 523.15 K was used. Experimental uncertainties for pressure, temperature, and composition have been calculated for each binary system. The data were correlated by means of the NRTL, UNIQUAC, UNIFAC, and Wilson models with satisfactory results.     

Estimation of (vapour + liquid) equilibrium of binary systems (tert-butanol + 2-ethyl-1-hexanol) and (n-butanol + 2-ethyl-1-hexanol) using an artificial neural network

(Vapour + liquid) equilibrium (VLE) data are important for designing and modelling of process equipment. Since it is not always possible to carry out experiments at all possible temperatures and pressures, generally thermodynamic models based on equations of state are used for estimation of VLE. In this paper, an alternate tool, i.e. the artificial neural network technique has been applied for estimation of VLE for the binary systems viz. (tert-butanol + 2-ethyl-1-hexanol) and (n-butanol + 2-ethyl-1-hexanol). The temperature range over which these models are valid is (353.2 to 458.2) K at atmospheric pressure. The average absolute deviation for the temperature output was in range 2% to 3.3%. The results were then compared with experimental data.     

Vapor–liquid equilibria for the carbon dioxide + propane system over a temperature range from 253.15 to 323.15 K

The isothermal vapor–liquid equilibrium (VLE) data were measured for the binary system of the carbon dioxide + propane at eight temperatures ranging from 253.15 to 323.15 K. Since the blends are natural refrigerants and have good thermophysical properties, they are considered as promising alternative refrigerants. The VLE measurement was performed at pressures up to 7.2 MPa in the circulation type equipment with a view cell. The binary system was found to be a zeotropic mixture in the tested temperature range and could be correlated with a sufficient accuracy by using the Peng–Robinson equation of state (PR EoS) with the van der Waals one fluid mixing rule. A comparison with published experimental VLE data has been carried out by means of the PR equation of state.     

(Vapour + liquid) equilibria of the {1,1-difluoroethane (HFC-152a) + n-butane (HC-600)} system

Binary (vapour + liquid) equilibrium data were obtained for the {1,1-difluoroethane (HFC-152a) + n-butane (HC-600)} system at temperatures from 313.15 K 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 Peng–Robinson equation of state using the Wong–Sandler mixing rules. This system shows positive azeotropic phase behaviour.     

(Vapour + liquid) equilibria for the binary mixtures (1-propanol + dibromomethane,or + bromochloromethane,or + 1,2-dichloroethane or + 1-bromo-2-chloroethane) at T = 313.15 K

Isothermal (vapour + liquid) equilibria (VLE) at 313.15 K have been measured for liquid 1-propanol + dibromomethane, or + bromochloromethane or + 1,2-dichloroethane or + 1-bromo-2-chloroethane mixtures.The VLE data were reduced using the Redlich–Kister equation taking into consideration the vapour phase imperfection in terms of the 2nd molar virial coefficients. The excess molar Gibbs free energies of all the studied mixtures are positive and ranging from 794 J · mol⁻¹ for (1-propanol + bromochloromethane) and 1052 J · mol⁻¹ for (1-propanol + 1-bromo-2-chloroethane), at x = 0.5. The experimental results are compared with modified UNIFAC predictions.