Modelling (vapour + liquid) and (vapour + liquid + liquid) equilibria of {water (H2O) + methanol (MeOH) + dimethyl ether (DME) + carbon dioxide (CO2)} quaternary system using the Peng–Robinson EoS with Wong–Sandler mixing rule

The (vapour + liquid) equilibria (VLE) and (vapour + liquid + liquid) equilibria (VLLE) binary data from literature were correlated using the Peng–Robinson (PR) equation of state (EoS) with the Wong–Sandler mixing rule (WS). Two group contribution activity models were used in the PRWS: UNIFAC–PSRK and UNIFAC–Lby. The systems were successfully extrapolated from the binary systems to ternary and quaternary systems. Results indicate that the PRWS–UNIFAC–PSRK generally displays a better performance than the PRWS–UNIFAC–Lby.     

Isobaric (vapour + liquid) equilibria for sulfolane with toluene, ethylbenzene, and isopropylbenzene at 101.33 kPa

Isobaric (vapour + liquid) equilibrium data have been measured for the (toluene + sulfolane), (ethylbenzene + sulfolane), and (isopropylbenzene + sulfolane) binary systems with a modified Rose-Williams still at 101.33 kPa. The experimental data of binary systems were well correlated by the non-random two-liquid (NRTL) and universal quasi-chemical (UNIQUAC) activity coefficient models for the liquid phase. All the experimental results passed the thermodynamic consistency test by the Herington method. Furthermore, the model UNIFAC (Do) group contribution method was used. Sulfolane is treated as a group (TMS), the new group interaction parameters for CH₂–TMS, ACH–TMS and ACCH₂–TMS were regressed from the VLE data of (toluene + sulfolane) and (ethylbenzene + sulfolane) binary systems. Then these group interaction parameters were used to estimate phase equilibrium data of the (isopropylbenzene + sulfolane) binary system. The results showed that the estimated data were in good agreement with the experimental values. The maximum and average absolute deviations of the temperature were 4.50 K and 2.39 K, respectively. The maximum and average absolute deviations for the vapour phase compositions of isopropylbenzene were 0.0237 and 0.0137, respectively.     

The phase envelopes of alternative solvents (ionic liquid,CO2) and building blocks of biomass origin (lactic acid,propionic acid)

Solid–liquid, liquid–liquid and vapour–liquid equilibrium measurements for binary and ternary systems containing building blocks of biomass origin such as propionic acid, lactic acid and alternative solvents like carbon dioxide and 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquid have been carried out at 313.15 K. The binary solid–liquid and liquid–liquid equilibrium measurements were performed at ambient pressure. The vapour–liquid equilibrium was studied in the range of pressure from 3.54 to 12 MPa while ternary systems were examined at 9, 10 and 12 MPa. The samples from the coexisting phases were taken and the compositions of both liquid and vapour phases were determined experimentally. The three-phase system was observed for lactic acid + ionic liquid + CO₂ as well. The achieved results were correlated using the Peng–Robinson equation of state with the Mathias–Klotz–Prausnitz mixing rule. The set of interaction parameters for the employed equations of state and the mixing rule for the investigated systems were obtained.     

Isothermal and isobaric (vapour + liquid) equilibria of (N,N- dimethylformamide + 2-propanol + 1-butanol)

The isothermal and isobaric (vapour  +  liquid) equilibria (v.l.e.) for (N, N - dimethylformamide  +  2-propanol  +  1-butanol) and the binary constituent mixtures were measured with an inclined ebulliometer. The experimental results are analyzed using the UNIQUAC equation with temperature-dependent binary parameters. The comparison between the experimental and literature results for binary systems is given. The ternary v.l.e. values are predicted from the binary results.     

(Vapour + liquid) equilibria of the {trifluoromethane (HFC-23) + propane} and {trifluoromethane (HFC-23) + n-butane} systems

Isothermal (vapour + liquid) equilibrium data were measured for the two systems, {trifluoromethane (HFC-23) + propane} and {trifluoromethane (HFC-23) + n-butane}, at temperatures ranging from 283.15 K to 313.15 K at 10 K intervals. These experiments were performed with a circulating-type apparatus and on-line gas chromatography. Experimental data were well correlated by the Peng–Robinson equation of state using the Wong–Sandler mixing rules and the NRTL model.     

Isobaric (vapour+liquid) equilibria data for the binary systems (toluene+acetic acid) and (toluene+methyl ethyl ketone) at atmospheric pressure

Isobaric vapour–liquid equilibrium data have been measured for the binary systems toluene (1) + acetic acid (2) and toluene (1) + methyl ethyl ketone (2) at atmospheric pressure. An all-glass Fischer–Labodest-type apparatus, capable of handling pressures from 0.25 to 400 kPa and temperatures up to 523.15 K was used. The data were correlated by means of the NRTL, UNIQUAC, WILSON models and the applied UNIFAC model with satisfactory results; the relevant parameters are given and results were tested with regard to thermodynamic consistency using the methods of a modified Redlich–Kister and Herington equations.     

Experimental study of high pressure phase equilibrium of (CO2 + NO2/N2O4) mixtures

Experimental bubble pressure, as well as liquid density of (CO₂ + NO₂/N₂O₄) mixtures are reported at temperatures ranging from (298 to 328.45) K. Experiments were carried out using a SITEC high-pressure variable volume cell. Transition pressures were obtained by the synthetic method and liquid density was deduced from measurement of the cell volume. Correlation of experimental results was carried out without considering chemical equilibrium of NO₂/N₂O₄ system. (Liquid + vapour) equilibrium was found to be accurately modelled using the Peng–Robinson equation of state with classical quadratic mixing rules and with a binary interaction coefficient k_ij equal to zero. Nevertheless, modelling of liquid density values was unsatisfactory with this approach.     

Solid + liquid equilibria of (n-alkane + cyclohexane) mixtures at high pressures

Solid+liquid equilibria (SLE) of [n-alkanes (tridecane, hexadecane, octadecane, or eicosane) + cyclohexane] at very high pressures up to about 1.0 GPa have been investigated in the temperature range from 293 to 363 K using a thermostated apparatus for the measurements of transition pressures from the liquid to the solid state in two component isothermal solutions. The freezing temperature of each mixture increases monotonously with increasing pressure. The eutectic point of the binary systems shifts to a higher temperature and to a higher n-alkane concentration with increasing pressure. The pressure–temperature–composition relation of the high-pressure solid–liquid equilibria, a polynomial based on the general solubility equation at atmospheric pressure, was satisfactorily used. Additionally, the SLE of the binary system (tridecane+cyclohexane) at normal pressure was measured by the dynamic method. The results at high pressure for all systems were compared to that at normal pressure.     

Vapor–liquid equilibria and critical points of the CO2 + 1-hexanol and CO2 + 1-heptanol systems

Vapor–liquid equilibria (VLE), vapor–liquid–liquid equilibria (VLLE) and critical point (CP) data for the carbon dioxide+1-hexanol (at 324.56, 353.93, 397.78, 403.39, 431.82 and 432.45 K up to 20 MPa) and carbon dioxide+1-heptanol (at 313.14, 333.16, 373.32, 411.99 and 431.54 K up to 21 MPa) systems are reported. Phase behavior measurements were made in a new equilibrium cell based on the static-analytic method and capable of measurements up to 60 MPa and 673 K. The Peng–Robinson equation of state (EoS) with the Wong–Sandler mixing rules and temperature independent parameters was able to correlate and extrapolate the VLE for the carbon dioxide+1-hexanol system. However, in order to obtain good agreement with experimental data for the carbon dioxide+1-heptanol system, the mixture EoS parameters were adjusted to the experimental VLE data at each temperature.     

Phase equilibria in binary mixtures of ethane + docosane and molar volumes of liquid docosane

Experimental results for various types of phase behaviour which can occur in the binary ethane + docosane system are presented. The experimental data cover various two-phase boundaries and the three-phase equilibria solid docosane + liquid + vapour and liquid + liquid + vapour. In addition, p,V,T measurements of liquid docosane are carried out. The experimental work is performed within a temperature range of ∼ 290–370 K and at pressures of up to 16 MPa.     

Vapour—liquid equilibrium of the systems 1-propanol—2,2,4-trimethylpentane and 2-propanol-n-hexane

The vapour—liquid equilibrium data were measured for the binary systems 2-propanol—n-hexane at 328.21 K and 1-propanol—2,2,4-trimethylpentane at 328.37 K and 348.52 K by using the recirculation still proposed by Berro et al. (1975). The excess volumes for these systems were measured with an Anton Paar densimeter. The reduction of VLE data and analysis of experimental errors were performed. The NRTL temperature-dependence parameters were estimated. The measured VLE data and the activity coefficients were compared with the values predicted by the chemical-reticular group-contribution method (CRG) (Neau and Péneloux, 1979). For both systems satisfactory agreement was found. This proves that the CRG model can be used to predict the vapour—liquid equilibria of alcohol—alkane systems containing branched components.     

(Vapour + liquid) equilibria for (2,2-dimethoxypropane + methanol) and (2,2-dimethoxypropane + acetone)

The isothermal and isobaric (vapour + liquid) equilibria for (2,2-dimethoxypropane + methanol) and (2,2-dimethoxypropane + acetone) measured with an inclined ebulliometer are presented. The experimental results are analysed using the UNIQUAC equation with the temperature-dependent binary parameters with satisfactory results. Isobaric (vapour + liquid) equilibria data for these systems at p=99.99 kPa are compared with the literature data. Experimental vapour pressure of 2,2-dimethoxypropane are also included.     

Phase equilibria study in binary systems (tetra-n-butylphosphonium tosylate ionic liquid + 1-alcohol, or benzene, or n-alkylbenzene)

Ambient pressure (solid + liquid) equilibria (SLE) and (liquid + liquid) equilibria (LLE) of binary systems--ionic liquid (IL) tetra- n-butylphosphonium p-toluenesulfonate + 1-alcohol (1-butanol, 1-hexanol, 1-octanol, 1-decanol, or 1-dodecanol), benzene, or n-alkylbenzene (toluene, ethylbenzene, n-propylbenzene)-have been determined by using dynamic method in a broad range of mole fractions and temperatures from 250 to 335 K. For binaries containing alcohol, simple eutectic diagrams were observed with complete miscibility in the liquid phase. Only in the case of system [IL + n-propylbenzene] was mutual immiscibility with an upper critical solution temperature (UCST) with low solubility of the IL in the alcohol and high solubility of the alcohol in the IL detected. The basic thermal properties of pure IL, i.e., melting and glass-transition temperatures as well as enthalpy of melting, have been measured with differential scanning microcalorimetry technique (DSC). Well-known UNIQUAC, Wilson, NRTL, NRTL1, and NRTL2 equations have been fitted to obtain experimental data sets. For the system containing immiscibility gap [IL + n-propylbenzene], parameters of the equations have been derived only from SLE data. As a measure of goodness of correlations, root-mean square deviations of temperature have been used. These experimental results were compared to the previously measured binary systems with tetra- n-butylphosphonium methanesulfonate. Changing anion from methanesulfonate to p-toluenesulfonate decreases solubilities in systems with alcohols and increases the solubilities in binary systems with benzene and alkylbenzenes.     

Phase equilibria in binary mixtures of propane + acenaphthene

In the near-critical region of propane, phase equilibria of binary mixtures of propane + acenaphthene have been investigated experimentally. Apart from the three-phase equilibrium solid acenaphthene + liquid + vapour, two-phase boundaries liquid + vapour and solid acenaphthene + liquid have been investigated over the entire mole fraction range. The measurements were performed in the temperature region 350–420 K with pressures up to 10 MPa.     

Liquid–liquid equilibria for binary systems of tert-amyl ethyl ether (TAEE), isopropyl tert-butyl ether (IPTBE) and di-sec-butyl ether (DSBE) with water and for ternary systems with methanol or ethanol

The liquid–liquid equilibria for binary systems of tert-amyl ethyl ether (TAEE) + water, isopropyl tert-butyl ether (IPTBE) + water and di-sec-butyl ether (DSBE) + water are analytically determined in the temperature range 278.65–358 K. Additionally, tie-lines for six ternary systems of TAEE, IPTBE and DSBE with methanol and water or with ethanol and water are also measured at 298.15 K. All the measured binary and ternary data were correlated with the NRTL and UNIQUAC model. The reliability of the experimental tie-line data for ternary systems was ascertained by using the Othmer–Tobias correlation.     

(Vapour + liquid) equilibria for (2-ethoxypropene + acetone) and (2-ethoxypropene + butanone)

The isothermal and isobaric (vapour + liquid) equilibria for (2-ethoxypropene + acetone) and (2-ethoxypropene + butanone) measured with an inclined ebulliometer are presented. The experimental results are analyzed using the UNIQUAC equation with the temperature-dependent binary parameters with satisfactory results. Experimental vapour pressures of 2-ethoxypropene are also included.     

Calculation of high pressure vapour—liquid equilibria for systems containing polar substances with the use of an augmented van der Waals equation of state

An augmented van der Waals equation of state based on a perturbation theory has been applied to the calculation of high pressure vapour—liquid equilibria for systems containing polar substances. The equation of state comprises four terms, which imply the contributions from repulsion, symmetric, non-polar asymmetric, and polar asymmetric interactions. The characteristic parameters of each pure substance have been determined by three methods with the use of vapour pressures and saturated liquid densities. Mixing models for the terms of the repulsion, symmetric, and non-polar asymmetric interactions are the same as used previously. Two types of mixing models based on a three-fluid model and/or a one-fluid model are developed for the polar asymmetric term. The polar asymmetric term has a large effect on the prediction of the vapour—liquid equilibrium. With the introduction of a binary interaction parameter, the equation is found to be useful in correlating the vapour—liquid equilibria for a system containing a polar substance except near a critical region.     

Vapour-liquid equilibrium data for the systems C2H6 + N2, C2H4 + N2, C3H8 + N2, and C3H6 + N2

High pressure vapour-liquid equilibrium data for the C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂ systems are presented. The data are obtained isothermally in the range from 200 K to 290 K. For each point of data, temperature, pressure and liquid and vapour phase mole fractions are measured.Values for the vapour phase mole fractions are calculated from the obtained pressure, temperature and liquid phase mole fractions. The calculated values are compared with the experimental results, and it is found that the average mean deviation between calculated and experimental mole fractions is less than 0.009 for the systems considered in this work.     

PVTx measurements for N2O + CH3F, N2O + CH2F2, and N2O + CHF3 binary systems

Isochoric PVTx measurements have been performed for the binary system of nitrous oxide + CH₃F (R41), +CH₂F₂ (R32), and +CHF₃ (R23) using a new experimental set-up. The experiments covered both the two-phase region and the superheated vapor region and were performed within the temperature range 214–358 K and within a pressure range from 270 to 5600 kPa. Data have been collected for not less than four compositions for each system. The vapor–liquid equilibrium data were derived correlating the experimental data by means of the Carnahan–Starling–De Santis equation of state. The studied systems show a positive deviation from the Raoult's law. The results obtained were compared with the Burnett PVTx data. The two methods showed a mutual consistency within an acceptable margin of error. No other experimental PVTx data were found in the literature for these binary systems.     

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.