Isamu Nagata

On the thermodynamics of alcohol solutions. Phase equilibria of binary and ternary mixtures containing any number of alcohols

Abstract Nagata, I., 1985. On the thermodynamics of alcohol solutions. Phase equilibria of binary and ternary mixtures containing any number of alcohols. Fluid Phase Equilibria , 19: 153–174. Binary vapor—liquid and liquid—liquid equilibrium data for alcohol solutions includin one or two alcohols are correlated with the UNIQUAC associated solution theory (Nagata and Kawamura). The theory uses pure liquid association constants determined by the method of Brandani and a single value of the enthalpy of the hydrogen bond equal to −23.2 kJ mol −1 for pure alcohols. For alcohol-active nonassociating component mixtures and alcohol—alcohol mixtures the theory involves additional solvation constants. The theory is extended to contain ternary mixtures with any number of alcohols. Ternary predictions of vapor—liquid and liquid—liquid equilibria are performed using only binary parameters. Good agreement is obtained between calculated and experimental results for many representative mixtures.

Determination of association constants for alcohols based on ethers as homomorphs

Abstract Hofman, T. and Nagata, I., 1986. Determination of association constants for alcohols based on ethers as homomorphs. Fluid Phase Equilibria, 25: 113–128. A new, improved version of the method for determining the association constants of alcohols from the properties of pure substances is presented. The proposed procedure assumes both the isomeric ether as the alcohols homomorph and ceases ignoring the volume change of mixing. Obtained values of enthalpies of association with are closer to the experimental ones than those calculated by means of standard methods, confirm both the credibility of accepted assumptions and the usefulness of the present approach.

Excess molar enthalpies of {methanol or ethanol + (2-butanone + benzene)} at 298.15 K

Abstract The excess molar enthalpies of (methanol + 2-butanone + benzene) and (ethanol + 2-butanone + benzene) at 298.15 K, measured with an isothermal dilution calorimeter, are reported. The experimental results are compared with those calculated from an association model based on mole-fraction statistics.

Thermodynamics of alcohol-unassociated active component liquid mixtures

Abstract An associated solution theory based on the UNIQUAC equation is developed to describe the excess properties of the alcohols in unassociated active components. The theory includes two association constants: the one for the alcohols, the other for alcohol-unassociated active component complexes. The theory reproduces well the activity coefficients of the ethanol—trichloromethane system having a maximum and a minimum and it also fits very skewed excess enthalpy curves for alcohol—benzene, alcohol—tetrachloromethane, etc. Prediction of ternary vapor—liquid and liquid—liquid equilibrium and excess enthalpy data has been carried out with good accuracy from binary parameters without adding any ternary constant.

Representation of Multicomponent Liquid-Liquid Equilibria for Aqueous and Organic Solutions Using a Modified UNIQUAC Model

A modified form of the UNIQUAC model is presented to accurately reproducebinary phase equilibria and ternary and quaternary liquid-liquid equilibria ofaqueous and organic solutions. The model gives a good representation in thereproduction of binary coexistence curves over a wide temperature range usingtemperature-dependent parameters and of binary vapor-liquid equilibria usingtwo binary energy parameters, and in the correlation of ternary and quaternaryliquid-liquid equilibria using ternary and quaternary parameters, in addition tobinary parameters. The quaternary calculated results are compared with thoseobtained from the modified Wilson and extended UNIQUAC models.

Modification of the extended uniquac model for correlating quaternary liquid—liquid equilibrium data

Abstract The extended UNIQUAC model with binary and ternary parameters is modified to include additional quaternary parameters for correlating quaternary liquid—liquid equilibrium data. The quaternary parameters are due to unlike four-body interaction. These parameter-containing terms vanish whenever the quaternary degenerates to a ternary. It is shown that the proposed model works well for the correlation of two non-aqueous and five aqueous quaternary data sets.

Vapor—liquid equilibria for the ternary Ethanol—2-butanone—benzene system at 298.15 K

Abstract Vapor—liquid equilibrium data for the ternary ethanol—2-butanone—benzene system and its constituent binary systems at 298.15 K are presented. The results are correlated with the Wilson, original and modified UNIQUAC equations and the UNIFAC group contribution method.

Ternary liquid—liquid equilibria and their representation by modified NRTL equations

Abstract Experimental liquid—liquid equilibrium data are reported for the systems acetonitrile—acetone—cyclohexane at 318.15 K and acetonitrile—methyl acetate—cyclohexane at 313.15 K. Two modified forms of the NRTL equation proposed by Renon are presented by substituting local surface fractions for local mole fractions and further by including Guggenheims combinatorial entropy for athermal mixtures whose molecules differ in size and shape. The resultant equations involve three adjustable parameters and are extended to multicomponent systems without adding ternary (or higher) parameters. Calculated results of vapor—liquid and liquid—liquid equilibria for typical binary and ternary mixtures are presented.

Excess enthalpies of binary and ternary mixtures of methanol with acetone, chloroform, benzene, and tetrachloromethane

Abstract Molar excess enthalpies at 298.15 K measured using an isothermal dilution calorimeter are reported for the binary mixtures methanol-acetone, methanol-chloroform and methanol-tetrachloromethane, and for the ternary mixtures methanol-chloroform-acetone and methanol-benzene-tetrachloromethane. The results are analyzed using an associated-solution theory which includes four equilibrium constants for the self-association of methanol, and solvation equilibrium constants between unlike molecules.

Ternary liquid—liquid equilibria for acetonitrile—ethanol—cyclohexane and acetonitrile—2-propanol—cyclohexane

Abstract Liquid—liquid equilibrium data were obtained for two ternary systems: acetonitrile— ethanol—cyclohexane at 40°C, and acetonitrile—2-propanol—cyclohexane at 50°C. Binary vapor—Liquid equilibrium data were measured for acetonitrile—2-propanol at 50°C. The binary parameters of the Zeta and effective Zeta equations were evaluated from equilibrium data for binary pairs. The parameters obtained were used to predict the ternary liquid—liquid equilibrium data for six systems involving the present systems and the ternary vapor—liquid equilibrium data for one completely miscible system and two partially miscible systems without adding any ternary parameter. A heterogeneous area calculated by the Zeta equation is in general too large and does not decrease appreciably with increasing values of the third parameter ζ of the Zeta equation. However, the effective Zeta equation works much better than the original Zeta equation in data reduction.