Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Static relative permittivities (?r) of water + ethane-1,2-diol and water + propane-1,2,3-triol mixtures were measured at the mole fraction of organic component (x2) from 0 to 0.8 at 0.2 intervals under pressures up to 300 MPa at the temperature 298.15 K. The relative permittivities at 0.1 MPa (?r(P0)) against x2 for both aqueous mixtures in this work were correlated with a polynomial equation of x2 and were compared with the literature values. The relative permittivities at pressure P (?r(P0)) were also correlated with the polarization (p) for both aqueous mixtures, and reasonable correlations were obtained by use of only one adjustable parameter (k12). The experimental ?r results as a function of P for each mixture were fitted to a Tait-type equation, and the Tait-type parameters, A and B, were determined. A comparison between composition dependence of (@ ln ?r/@P)T at 0.1 MPa and 298.15 K, (@ ln ?r/@P)T,P0, calculated from values of ?r(P0) and the Tait-type parameters and that of the isothermal compressibility at 0.1 MPa, ?T,P0, was made for both aqueous polyhydric alcohol mixtures. In addition, composition dependence of ?r -2(@?r/@P)T values at 0.1 MPa, ?r(P0)-2(@?r/@P)T,P0, evaluated from ?r(P0), A, and B values were correlated with a quadratic equation of x2. An empirical equation by Marcus for estimating (@ ln ?r/@P)T,P0 values was used, and the estimated results were compared with the experimental ones. Furthermore, a combination equation of the correlation equations for ?r(P0) and ?r(P0)-2(@?r/@P)T,P0 with x2 was used to obtain (@ ln ?r/@P)T,P0 values, and then it was found that the calculated values reproduce the composition dependence of (@ ln ?r/@P)T,P0 well.