R. Holub

PVT properties of liquids and liquid mixtures: a review of the experimental methods and the literature data

Abstract This paper comprises a classification of various techniques of experimental determination of the PVT properties of liquids and liquid mixtures, and gives brief descriptions of the methods and of the instruments. Empirical equations of state suitable for correlating experimental data are summarized. Literature references to published data compilations are also given. Tables give a bibliography on experimental data for more than 350 pure liquids and 170 binary liquid mixtures. Other important information included in the tables are the range, average step width, and precision of temperature and pressure of measurements, the method used, and a precision of the measured quantity.

Vapour—liquid equilibrium in binary systems formed by acetonitrile, 2-butanone and 1,2-dichloroethane

Abstract Isothermal vapour—liquid equilibria have been determined for 2-butanone + acetonitrile at 333.67 K, and for 2-butanone + 1,2-dichloroethane and acetonitrile + 1,2-dichloroethane at 333.15 K using a dynamic method. The apparatus used in these studies for the precise measurement of complete vapour—liquid equilibrium data is described and the reliability and accuracy of the measured data are considered in terms of the activity coefficients and of the dependences of the molar excess Gibbs energies on composition. Experimental inaccuracies are estimated for statistical treatment of the data both in terms of correlations and in consistency tests.

Infinite-dilution activity coefficients by comparative ebulliometry: Five systems containing the bromide or chloride group

Abstract Infinite-dilution activity coefficients for 1-bromopropane + acetonitrile, + ethyl acetate, + 1,1,1-trichloroethane, and 1-chlorobutane + acetonitrile, + ethyl acetate were measured using the technique of comparative ebulliometry. The data obtained enabled us to estimate the UNIFAC interaction parameters for Br/CCN. Br/CCOO, Br/CCl 3 , CCl/CCN, and CCl/CCOO which are not available in the 1982 revised version of the UNIFAC parameter table. Predictions from the limited data bases used were compared with recent vapor-liquid equilibrium data from literature for systems involving the group interactions in question.

Prediction of excess gibbs energy and excess enthalpy on the basis of non-analytical solution-of-groups concept

Abstract New possibilities on how to employ the Solution-of-Groups concept predicting excess Gibbs energy and excess enthalpy have been presented here. On the basis of the Solution-of-Groups concept a procedure has been proposed by means of which excess functions can be directly recalculated from one system to another. To apply this procedure the energy parameters of group interactions do not have to be adjusted nor is any particular equation or model needed to describe group contributions. The two prediction methods suggested, i.e. the method of combination of excess functions and that of corresponding partial quantities, utilize experimental information from a related system and some geometrical characteristics of the components in question. Using a given simple criterion, cases are defined in which these methods can be used. The relations derived generally have been successfully applied to a large number of binary systems containing n-alkane and/or n-alkylhomolog. Predictions of ternary systems have been tested too, but the applicability of the methods presented is somewhat limited in this direction.

Determination of the distribution ratio of substances at very low concentrations in liquid-liquid systems by the exponential concentration-change method

Abstract An Experimental method is described for determining the distribution ratio at very low concentrations of a substance in a two-phase system of partly or fully immiscible liquids. An exponential concentration-change method is described in which the system is washed by a liquid which is either the heavier binary phase or its main component. In the first part of the paper, relationships are derived on the basis of a balance-type description of a two-phase liquid system containing three components. The second part describes the design of an equilibrium vessel and associated apparatus and the procedure for determination of the distribution ratio. The procedure proposed has been tested in two modifications using the system water-diethylether-phenol: for washing with pure water, and washing with diethylether-saturated water. The results agree well with data available in the literature. The apparatus proposed can also be used to measure the mutual solubility of liquids which are miscible to a limited degree.