Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

(Solid + liquid) equilibria (SLE) of {n-alkanes (n-tridecane, n-hexadecane, n-octadecane) + n-hexane} at very high pressures up to about 1.0 GPa have been investigated in the temperature range from 293 to 363K using a thermostated apparatus for the measurements of transition pressures from the liquid to the solid state in two component isothermal solutions. The polynomial based on the general solubility equation at atmospheric pressure was satisfactorily used to the description of the pressuretemperature- composition relation of the high pressure (solid + liquid) equilibria. Additionally, the SLE of the binary system (n-tridecane + nhexane) at normal pressure was measured by the dynamic method. The results at higher pressures for every system were compared to those at normal pressure. The main aim of this work was to predict the SLE of the mixtures using only pure components data in a wide pressure range, far above the pressure range in which cubic equations of state are normally applied. The fluid phase is described by the corrected SRK-EOS using van der Waals one fluid mixing rules. The results of the predictions are compared with the experimental data presented in this paper {nalkanes (n-tridecane, n-hexadecane, n-octadecane) + n-hexane} and with experimental results presented previously {n-alkanes (n-tridecane, n-hexadecane, n-octadecane and n-eicosane) + cyclohexane}.