Isothermal Vapor-liquid Equilibrium Data Research Articles

Vapor–liquid equilibrium data for the difluoromethane (R32)–dimethyl ether (RE170) system at temperatures from 283.03 to 363.21 K and pressures up to 5.5 MPa

Isothermal vapour–liquid equilibrium data have been measured for the R32 + RE170 binary system at seven temperatures between 283.03 and 363.21 K, and pressures between 0.5 and 5.5 MPa. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the CEP/TEP laboratory. The data were obtained with uncertainties within ±0.02 K, ±0.0002 MPa and ±1% for molar compositions. The isothermal P, x, y data are well represented with the Peng and Robinson equation of state using the Mathias–Copeman alpha function and the Wong–Sandler mixing rules involving the NRTL g E model.

Vapour–liquid equilibrium data for the 1,1,1,2 tetrafluoroethane (R134a) + dimethyl ether (DME) system at temperatures from 293.18 to 358.15 K and pressures up to about 3 MPa

Isothermal vapour–liquid equilibrium data have been measured for the binary system R134a + DME at five temperatures between 293.18 and 358.15 K, and pressures between 0.4899 and 2.9442 MPa. The peculiarity of this system is the existence of an azeotrope with a minimum pressure, which disappears at 358.15 K. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the CENERG/TEP Laboratory. The data were obtained with uncertainties within ±0.02 K, ±0.0001 MPa and ±1% for molar compositions. The isothermal P, x, y data are well represented with the Redlich and Kwong equation of state using the Mathias–Copeman alpha function and the Huron–Vidal mixing rules involving the NRTL model.

Excess Molar Volume, Viscosity, and Molar Refraction Deviations, and Liquid?Vapor Equilibrium at 303.15 K for Chloroform + Acetonitrile Binary Mixture. An Infrared Study

Excess molar volume, viscosity deviation, and molar refraction deviation for the chloroform #x002B; acetonitrile system at 303.15 K were calculated from binary experimental results of density, viscosity, and refractive index over the whole mole fraction range, respectively. Isothermal vapor–liquid equilibrium data at the same temperature were also obtained and the excess molar Gibbs energy was calculated from these data. Each one of the properties was fitted to a Redlich–Kister type equation using least squares in order to obtain their dependencies on concentration. The presence of intermolecular association complexes was inferred from the viscosity deviations, leading to a 1:1 stoichiometric relationship. The recorded FTIR spectra confirm the existence of this type of hydrogen-bonded complex, making it possible, furthermore, to calculate the heteroassociation constant and enthalpy of formation of the hydrogen bond.

Vapor−Liquid Equilibrium Measurements of MTBE and TAME with Toluene

This paper presents binary vapor−liquid equilibria (VLE) for the ether−aromatic systems including 2-methoxy-2-methylbutane (TAME) and 2-methoxy-2-methylpropane (MTBE) with toluene. The data sets were measured using a dynamic experimental method over a temperature range from (308 to 323) K. The isothermal data were correlated using several liquid-phase excess Gibbs energy models including NRTL, UNIQUAC, and the Wilson model, with the respective model parameters fitted using the Marquardt optimization algorithm. Infinite dilution activity coefficients in the oxygenate-depleted region are reported. The isothermal VLE data are shown to be thermodynamically consistent.

Vapor–Liquid Equilibrium Data for the Sulfur Dioxide (SO2) + Difluoromethane (R32) System at Temperatures from 288.07 to 403.16 K and at Pressures up to 7.31 MPa

Isothermal vapor–liquid equilibrium data have been measured for the binary system R32 (difluoromethane) + SO2 at eight temperatures between 288.07 and 403.16 K, and at pressures in the range 0.417–7.31 MPa. The experimental method used in this work is of the static–analytic type, taking advantage of two pneumatic capillary samplers (RolsiTM, Armines’ patent) developed in the CENERG/TEP laboratory. The data were measured with uncertainties within ±0.02 K and ±0.0015 MPa, respectively, for temperatures and pressures and ±1% for molar compositions as a result of careful calibrations. The isothermal P, x, y data are well represented with the Peng–Robinson equation of state using the Mathias–Copeman alpha function and the Wong–Sandler mixing rules involving the NRTL model.

Vapor–liquid equilibria for the ternary system methanol + dimethyl carbonate + dimethyl oxalate and constituent binary systems at different temperatures

Isothermal vapor–liquid equilibrium data are measured for the ternary system methanol + dimethyl carbonate (DMC) + dimethyl oxalate (DMO) and constituent binary systems at different temperatures. The activity coefficients were found to be thermodynamically consistent and were correlated by the Wilson, NRTL and UNIQUAC equations. The correlated parameters of the constituent binary systems were used to calculate the phase behavior of the ternary mixture, which showed satisfactory agreement with the experiments.

Vapor–liquid equilibrium data for the sulfur dioxide (SO2) + 1,1,1,2,3,3,3-heptafluoropropane (R227ea) system at temperatures from 288.07 to 403.19 K and pressures up to 5.38 MPa: Representation of the critical point and azeotrope temperature dependence

Isothermal vapor–liquid equilibrium data have been measured for the binary system SO2 + R227ea (1,1,1,2,3,3,3-heptafluoropropane) at 10 temperatures between 288.07 and 403.19K, and at pressures in the range 0.276–5.38MPa. The peculiarity of this system is the existence of an azeotrope. The experimental method used in this work is of the static-analytic type, taking advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the Cenerg/TEP laboratory. The data were obtained with uncertainties within ±0.02K, ±0.0015MPa and ±1% for molar compositions.The isothermal P, x, y data are well represented with the Peng–Robinson equation of state using the Mathias Copeman alpha function and the Wong–Sandler mixing rules involving the NRTL model.

Vapor Pressure, Density, Viscosity and Refractive Index of Dimethyl Sulfoxide + 1, 4-Dimethylbenzene System

This work reports the experimental results of the isothermal vapor-liquid equilibrium data between 303.15 K and 333.15 K, densities, viscosities and refractive indices from 298.15 to 323.15 K of the dimethyl sulfoxide + 1, 4-dimethylbenzene system over the entire range of mixture composition. The obtained PTX data were correlated and estimated by the Wilson, NRTL and UNIFAC models. The excess Gibbs energy and activity coefficients were calculated and compared with the others excess properties. Excess molar volumes, viscosity deviations and deviations in refractivity were calculated from experimental data; all the computed quantities were fitted to the Redlich-Kister equation. The resulting excess functions were interpreted in terms of the interactions between the molecules in the binary system.

Vapour–liquid equilibrium data for the difluoromethane+1,1,1,2,3,3,3-heptafluoropropane system at temperatures from 283.20 to 343.38 K and pressures up to 4.5 MPa

Isothermal vapour–liquid equilibrium data for the difluoromethane (R32)-1,1,1,2,3,3,3-Heptafluoropropane (R227ea) binary system are presented at 283.20, 303.21, 323.21 and 343.38 K and pressures up to 4.5 MPa. The experimental method, used for this work, is of the static-analytic type. It takes advantage of mobile pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in our laboratory. The four P, x, y isothermal data have been represented with the Soave–Redlich–Kwong (SRK) equation of state and the MHV1 rules involving the NRTL model.

Vapor–liquid equilibrium data for the CO 2 + 1,1,1,2,3,3,3,-heptafluoropropane (R227ea) system at temperatures from 276.01 to 367.30 K and pressures up to 7.4 MPa

Isothermal vapor–liquid equilibrium data for the binary system CO 2 + R227ea (1,1,1,2,3,3,3-heptafluoropropane) were measured at 276.01, 293.15, 303.15, 305.17, 313.15, 333.15, 353.15 and 367.30 K and pressures up to 7.4 MPa. The experimental method used in this work is of the static-analytic type. It takes advantage of two pneumatic capillary samplers (Rolsi™, Armines’ patent) developed in the Cenerg/TEP laboratory. The eight sets of isothermal P, x, y data are represented with the Peng–Robinson equation of state using the Wong–Sandler mixing rules involving the NRTL model.

Multiphase Coexistence for Mixtures Containing Water, 2-Propanol, and Isopropyl Acetate

Isothermal vapor-liquid equilibrium (VLE) data were measured for isopropyl acetate + 2-propanol at temperatures from 333.15 to 373.15 K, and isothermal vapor-liquid-liquid equilibrium (VLLE) data were determined experimentally for isopropyl acetate + water and water + 2-propanol + isopropyl acetate at temperatures from 308.15 to 358.15 K. The UNIQUAC model with linearly temperature-dependent parameters and ideal gas-phase assumption represents satisfactorily the VLLE properties for the binary system of isopropyl acetate + water. With the parameters determined from the VLE or the mutual solubility data of the constituent binaries, the UNIQUAC model predicts well the VLLE properties of the ternary system of water + 2-propanol + isopropyl acetate, except for the compositions in the organic-rich phase. The representation for the binodal loci was improved, while the six parameters of the UNIQUAC model were determined, simultaneously, from the isothermal VLLE ternary data.

Vapor−Liquid Equilibrium Data for the Azeotropic Difluoromethane + Propane System at Temperatures from 294.83 to 343.26 K and Pressures up to 5.4 MPa

Isothermal vapor-liquid equilibrium data for the Difluoromethane (R32) + Propane binary system are presented at 278.10, 294.83, 303.23, 313.26 and 343.26 K and pressures up to 5.4 MPa. The experimental method is the static-analytic type. It takes advantage of mobile pneumatic capillary samplers (Rolsi™, Armines' patent) developed in our laboratory. At a fixed temperature the azeotrope vapor pressure is larger then those of the pure component. The particularity of R32-Propane azeotropic binary system is to present in two critical point over the critical temperature if the azeotrope. This particular behavior has been proved and even shown visually by means of two supplementary experiments with equipment based on the static-synthetic method involving a variable volume cell. Data along the five isotherms have been represented with the Soave-Redlich-Kwong (SRK) equation of state and MHV1 mixing rules involving the NRTL model. We have calculated the location of the azeotrope using the equality of Equation of State attractive parameter between the two phases.

Vapor–liquid equilibria of propionic acid–water system in the presence of different types of inorganic salts: effect of temperature and salt concentration

Isothermal vapor–liquid equilibrium data at 40 and 50 °C were obtained by using a headspace gas chromatography (GC) (one of the static methods) for the propionic acid–water system in the presence and absence of chloride salts. Propionic acid was salted-out in the presence of any chloride salt, in the following order: aluminum chloride>calcium chloride>sodium chloride>ammonium chloride. The effects of AlCl 3, CaCl 2, and NaCl, at the three concentration levels 0.2, 0.5 and 1.0 m, revealed an increase in salting out of propionic acid with the increase of salt concentration. No remarkable effect of temperature on the VLE data and consequently on the enhancement factor of propionic acid (i.e. the ratio of relative volatilities with and without salt) was observed. The modified Furter correlation was successful in correlating the effect of dissolved salts on the VLE of the systems studied.

Phase equilibria of 1,1,1-trifluoroethane (HFC-143a) + 1,1,1,2-tetrafluoroethane (HFC-134a), and + 1,1-difluoroethane (HFC-152a) at 273.15, 293.15, 303.15, and 313.15 K

Isothermal vapor–liquid equilibrium data were determined for the binary systems of 1,1,1-trifluoroethane (HFC-143a)+1,1,1,2-tetrafluoroethane (HFC-134a) and 1,1,1-trifluoroethane (HFC-143a)+1,1-difluoroethane (HFC-152a) at 273.15, 293.15, 303.15, and 313.15 K in a circulation-type equilibrium apparatus. The experimental data were well correlated with the Carnahan–Starling–De Santis (CSD) equation of state within ±1.0%. Azeotropic behavior has not been found in any of these mixtures.

Measurement and Correlation of Isothermal Vapor−Liquid Equilibrium Data for the System Ethanol + 2-Propanol + Barium Iodide

Isothermal vapor-liquid equilibrium data for the system ethanol + 2-propanol + barium iodide at three constant salt molalities (0.5, 1.0 and 1.5 mol.kg -1 ) have been measured with the help of headspace gas chromatography at 40.3, 55.3, and 70.6 °C. The experimental data were correlated using four electrolyte models: an electrolyte NRTL model, an extended UNIQUAC model, an electrolyte UNIFAC model, and the LIQUAC model.

Vapor−Liquid Equilibria and Excess Enthalpy Data for the Binary System Propionic Aldehyde + 2-Methyl-2-butanol at 333.15 K

Isothermal vapor-liquid equilibrium (VLE) and excess enthalpy (HE) data are reported for the system propionic aldehyde + 2-methyl-2-butanol at 333.15 K. The data were measured by means of a computer-operated static apparatus and isothermal flow calorimetry, respectively. The experimental data were correlated simultaneously by using linear temperature-dependent UNIQUAC parameters.

Vapor−Liquid Equilibrium for the Binary Systems of Methanol + 2,4,4-Trimethyl-1-pentene at 331 K and 101 kPa and Methanol + 2-Methoxy-2,4,4-trimethylpentane at 333 K

Isothermal and isobaric vapor-liquid equilibrium data were measured for the system methanol + 2,4,4-trimethyl-1-pentene at 331 K and at 101 kPa. Isothermal vapor-liquid equilibrium data were also measured for methanol + 2-methoxy-2,4,4-trimethylpentane at 333 K. Vapor pressures were measured for 2-methoxy-2,4,4-trimethylpentane. The measurements were made with a recirculation still. The results were correlated with the Soave-Redlich-Kwong equation of state and the Wilson activity coefficient models.

Phase equilibrium properties of binary systems with diacetyl from a computer controlled vapour–liquid equilibrium still

Isothermal vapour–liquid equilibrium (VLE) data were obtained for binary mixtures of diacetyl with toluene and cyclohexane at 318.15, 328.15 and 338.15 K with the aid of a dynamic VLE still [Phase Equilibria: Measurement and Computation, Taylor and Francis, Bristol, PA, 1998]. A computer was used to control the temperature and pressure in the still. The excess thermodynamic properties, molar excess Gibbs energy ( G E), molar excess enthalpy or heat of mixing ( H E) and molar excess entropy ( S E) were calculated from the isothermal VLE data. Infinite dilution activity coefficients are also reported. The data were found to be thermodynamically consistent.

Vapor Liquid Equilibrium for the Binary Systems of 2-Methyl-2-propanol + 2,4,4-Trimethyl-1-pentene at 333 K and 348 K and 2-Butanol + 2,4,4-Trimethyl-1-pentene at 360 K

Isothermal vapor liquid equilibrium data were measured for two binary systems, 2-methyl-2-propanol + 2,4,4-trimethyl-1-pentene at 333 K and 348 K and 2-butanol + 2,4,4-trimethyl-1-pentene at 360 K. The measurements were made with a recirculation still. The results were correlated with the Soave-Redlich-Kwong equation of state and the Wilson activity coefficient model.

A new modification of the UNIQUAC equation including temperature dependent parameters

The UNIQUAC equation was modified by introduction of a linear temperature dependence of the volume and surface area parameters, r i and q i . The slope of r i and q i functions were found to be the same for hydrocarbons and pyridine. The modified equation was used for prediction of vapor–liquid equilibria (VLE) in binary mixtures of hydrocarbons and pyridine with hydrocarbons as well as for the prediction of the excess enthalpy ( H E) in binary mixtures formed by pyridine with aliphatic alkanes. The results obtained were compared with predictions by UNIFAC and further with UNIQUAC equation and its modification involving temperature dependant coordination number z. The proposed temperature dependence of the r i and q i parameters enables prediction of the VLE at various temperatures and leads to reasonable values of H E. The necessary input reduces to one set of isothermal VLE data. One set of UNIQUAC interaction parameters u ij is sufficient for representation of VLE in a wide range of temperature and to obtain a reasonable prediction of H E.