Temperature and Pressure Dependence of Volumetric Properties for Binary Mixtures of n-heptane and n-octane†

Darja Pečar* and Valter Doleček
Faculty of Chemistry and Chemical Egineerig, University of Maribor, Smetanova 17, 2000 Maribor, Slovenia.
Tel.: +386 2 2294 442, Fax.: +386 2 2527 774,
E-mail: darja.pecar@uni-mb.si

Abstract
The densities of n-heptane, n-octane and their binary mixtures were measured at 298.15, 323.15 and 348.15 K and within the pressure range 0.1 to 40 MPa using a vibrating tube densimeter. The reliability of this technique has been verified in our previous works. The partial molar volumes, excess molar volumes, isothermal compressibilities, isobaric thermal expansivities and internal pressures were calculated from the obtained densities. This study presents the dependence of densities, partial molar volumes, excess molar volumes, isothermal compressibilities, isobaric thermal expansivities and internal pressures on composition, temperature and pressure.

Keywords: Density, partial molar volume, excess molar volume, isothermal compressibility, isobaric thermal expansivity,
internal pressure, n-heptane, n-octane.