Isothermal Vapor-liquid Equilibrium Data Research Articles

Thermodynamics of associated solutions: Vapour-liquid equilibrium for solutions containing propanoic acid or butanoic acid with association in both phases

An association model was developed to correlate the isothermal vapour-liquid equilibrium data of the binary systems propanoic acid + benzene, + n-heptane, + chlorobenzene, + cyclohexane, + tetrachloromethane and + 2-butanone, and butanoic acid + 2-butanone. The model uses a concentration-dependent mole fraction association constant for carboxylic acids in the liquid phase, with allowance for molecular interactions between the true chemical species expressed by the NRTL (non-random two liquid) equation. The model quantitatively reproduces the experimental results in a satisfactory manner over the whole composition range.

Thermodynamics of associated solutions: Vapour-liquid equilibrium for the systems acetic acid-water and acetic acid-2-butanone with association in both phases

A model using a concentration-dependent liquid-phase association constant for acetic acid was employed to correlate isothermal vapour-liquid equilibrium data for binary solutions of acetic acid with water and 2-butanone. Results of data reduction show that cross-dimerization between acetic acid and water is required to represent satisfactorily two sets of literature data.

Nonclassical behaviour of binary mixtures in gas-liquid critical region and its quantitative description

The gas-liquid critical region is described by means of an exponential relation, parameters of which are independent of system. It can be used for the preparation of nonclassical fluid phase behaviour. The isothermal vapour-liquid equilibrium data on the sulphur hexafluoride-pentane system measured in neighbourhood of the critical point of SF6 are presented.

Isothermal vapor-liquid equilibria for the ternary ethanol-acetonitrile-chloroform system

Isothermal vapor-liquid equilibrium data for the three ternary systems containing ethanol have been reported from this laboratory ( 7 -3). This work presents similar measurements for the system ethanol-acetonitribchloroform at 40 OC and compares the experimental results with those calculated by the extended UNIQUAC equation (4). Vapor-liquid equilibrium data for the three binary systems constituting the present ternary system are available in the literature: for ethanol-acetonitrile at 40 OC (5); for ethanol-chloroform at 35 O C (6); for acetonitrile-chloroform at 40 OC (7).

Isothermal vapour-liquid equilibria for binary and ternary mixtures formed by acetonitrile, isobutanol and benzene

Isothermal vapour-liquid equilibrium data were measured for the binary acetonitrile-isobutanol and ternary acetonitrile-isobutanol-benzene systems at 60° C by using a vapour-recirculating equilibrium still. The experimental data were correlated by the extended UNIQUAC and UNIQUAC associated-solution models. The UNIQUAC associated-solution model gives better predicted values for the ternary system.

High pressure vapor-liquid equilibria of four binary systems containing carbon dioxide.

Isothermal vapor-liquid equilibrium data of four binary systems -carbon dioxide+pentane at 311.15 and 329.15K, +diethyl ether at 313.15K, +methyl terf-butyl ether at 310.15, 329.15 and 338.15K, and +1-pentene at 303.15, 313.15 and 328.60 K-were determined by using an apparatus with vapor and liquid alternative circulation over a pressure range from 0.5 to 9.1 MPa. Experimental data were correlated by applying the Soave-Redlich-Kwong equation of state with the conventional quadratic mixing rule and the DDLC-EOS unified model based on the conformal reference state. Results show that both models correlate the present data satisfactorily.

Liquid-liquid equilibria for ternary acetonitrile-ethanol-saturated hydrocarbon and acetonitrile-1-propanol-saturated hydrocarbon mixtures

Isothermal vapour-liquid equilibrium data for acetonitrile-1-propanol at 45° C were measured by use of a recirculating still. The liquid-liquid equilibria of (acetonitrile-etha-nol)-( n-hexane or n-heptane or n-octane) and those of (acetonitrile-1-propanol)-(cyclohexane or n-hexane or n-heptane) were obtained from measurements of tie-lines. The experimental results were compared with those calculated from the UNIQUAC associated-solution model.

Isothermal vapor-liquid equilibria for binary and ternary mixtures formed by 1-butanol, acetonitrile and benzene

Isothermal vapor-liquid equilibrium data are presented for the binary acetonitrile-1-butanol and ternary 1-butanol-acetonitrile-benzene systems at 60 °C. The experimental results are well correlated with the UNIQUAC associated-solution model.

Evaporation rates of solvent blends measured by gas chromatography

A gas chromatographic method that enables the measurement of individual and total evaporation rates from solvent blends has been developed; the composition of the remaining liquid can also be determined. The method offers definite advantages over the classical gravimetric methods. Isothermal vapour—liquid equilibrium data can also be obtained.

Excess Gibbs energies and excess volumes of some alcohol-methyl ester binary mixtures

Isothermal vapor—liquid equilibrium data for the mixtures 1-butanol-methyl propanoate and 1-butanol—methyl butanoate have been measured by using a recirculating still. The excess molar volumes of the same mixtures and those of the system 1-pentanol—methyl butanoate were obtained from measurements of the density with an Anton Paar densimeter. The vapor—liquid equilibrium data were reduced according to the maximum likelihood principle. The parameters of the NRTL, Wilson, and UNIQUAC equations were calculated. © 1987, American Chemical Society. All rights reserved.

Vapor-liquid equilibrium of mixtures formed by methanol, 2-propanol, and chlorobenzene

Isothermal vapor-liquid equilibrium data at 55/sup 0/C are presented for the binary system 2-propanol-chlorobenzene and the ternary system methanol-2-propanol-chlorobenzene. The experimental results are well correlated with the UNIQUAC associated-solution theory with binary parameters obtained from the maximum likelihood principle.

Isothermal vapour-liquid equilibria for binary mixtures ofn-octane with isomeric-butanols at 333·15 K

Isothermal vapour-liquid equilibrium (vle) data were measured for the binary systems ofn-octane with 1-butanol, 2-methyl-1-propanol, 2-butanol and 2-methyl-2-propanol at 333·15 K. The values of excess free energy, GmE, calculated are positive for all the systems. The results were correlated using Redlich-Kister and Wilson equations.

Excess thermodynamic properties of the binary mixtures of ethylenediamine with isomeric butanols

Isothermal vapour-liquid equilibrium data at 333·15 K and excess molar volumes of mixing at 298·15K for the binary mixtures of ethylenediamine with isomeric butanols were measured over the entire mole fraction range. The values of molar excess free energy,G m E , and excess volumes,V m E , are negative for all the four systems, indicating strong specific interactions between two unlike molecules. The branching of the alkyl chain of alcohol also affects the excess properties considerably.

Isothermal binary and ternary vapor-liquid equilibria for the systems containing methane, carbon dioxide, n-pentane and n-heptane at high pressures.

Isothermal vapor-liquid equilibrium (VLE) data were measured for two binary systems; methane-n-pentane and methane-n-heptane, and for two ternary systems; methane-CO2-n-pentane and methane-CO2-n-heptane at 343K with a new static type of VLE apparatus. It is distinguished by sampling devices which were specially designed to minimize the errors that sometimes occur during sampling operations under high pressure conditions. The binary VLE data were thermodynamically tested by means of enhancement factor method and total pressure method. Consequently they appeared to be consistent within the range of experimental error. All of the experimental data were compared with those calculated by the Peng-Robinson equation of state employing binary interaction parameters for every binary system. The estimated results have been shown to agree acceptably with those experimental results except in the region close to the critical point.

Excess thermodynamics functions of 1-propanol + methyl propanoate and 1-propanol + methyl butanoate systems

Isothermal vapour-liquid equilibrium data for the mixtures 1-propanol + methyl propanoate and 1-propanol + methyl butanoate have been obtained using a recirculating still designed by Berro (1982). The reduction of VLE data and analysis of experimental errors were performed. The excess molar enthalpies of the same mixtures were determined at 298.15 K using a Calvet microcalorimeter and their excess molar volumes using an Anton Paar densimeter. NRTL and UNIQUAC equations were fitted to the liquid-vapour equilibrium data and excess enthalpies assuming linearly temperature-dependent parameters.

Vapor-liquid equilibria for three aldehyde/hydrocarbon mixtures

Isothermal vapor-liquid equilibrium (VLE) data were measured for the mixtures n-pentane/propionaldehyde, n-heptane/n-butyraldehyde, and isobutyraldehyde/n-heptane at low pressures (100-1000 mmHg) by using a dynamic still. The data reported here are thermodynamically consistent according to the point-to-point consistency test. These data are correlated with five activity coefficient models with parameters estimated from the maximum likelihood method. Also, UNIFAC parameters were estimated for the aldehyde/hydrocarbon functional-group interactions based on the new data.

Isothermal and isobaric vapour-liquid equilibrium data in the tetrachloromethane-sec-butyl alcohol system

Isothermal vapour-liquid equilibrium data at 65, 73 and 80 °C and isobaric ones at 101.3 kPa were measured in the tetrachloromethane-sec-butyl alcohol system. A modified circulation still of the Gillespie type was used for the measurements. Under the conditions of measurement, the system exhibits positive deviations from Raoult's law and minimum boiling-point azeotropes. The experimental data were fitted to a number of correlation equations, the most suitable being the Wilson equation.

Isothermal and isobaric vapour-liquid equilibrium data in the tetrachloromethane-tert-butyl alcohol system

Isothermal vapour-liquid equilibrium data at 55, 63 and 70 °C and isobaric ones at 101.3 kPa were measured in the tetrachloromethane-tert-butyl alcohol system. A modified circulation still of the Gillespie type was used for the measurements. Under the conditions of measurement, the system exhibits positive deviations from Raoult's law and minimum boiling-point azeotropes. The experimental data were fitted to a number of correlation equations, the most suitable being the Wilson equation.

Isothermal and isobaric vapour-liquid equilibrium data in the tetrachloromethane-n-butyl alcohol system

Isothermal vapour-liquid equilibrium data at 65, 73 and 80 °C and isobaric ones at 101.3 kPa were measured in the tetrachloromethane-n-butyl alcohol system. A modified circulation still of the Gilespie type was used for the measurements. Under the conditions of measurements, the system exhibits positive deviations from Raoult's law and minimum boiling-point azeotropes. The experimental data were fitted to a number of correlation equations. The best correlation was reached with the Wilson equation but the regression failed in some cases. Therefore the results for the 5th order Redlich-Kister equation are presented.

Isothermal vapor-liquid equilibria of propylene oxide-ethylene and ethyl ether-ethylene systems at high pressures.

Isothermal vapor-liquid equilibrium data of propylene oxide-ethylene and ethyl ether-ethylene systems were measured by a static method at 25°C and 40°C. The consistency of experimental results is examined by an enhancement factor of the vapor phase and by the Henry constant (f2/x2) of the liquid phase. By use of the Lewis fugacity rule for ethylene in the vapor phase, the activity coefficients of liquid phase and the fugacity coefficients of vapor phase are evaluated from themodynamic relationships. The P-x-y data of both systems are correlated with the Redlich-Kwong equation modified by Soave and the perturbation equation proposed by Gubbins and Twu. In the normal probability plot of the residuals, the SRK equation gives better correlation results for both systems.