Experimental and Theoretical Investigation of the Thermodynamic Properties of Sulfur Hexafluoride in the Liquid Phase.

摘要

The density of liquid sulfur hexafluoride (SF6) was measured from 0 to 50 C at 5 degree intervals, at pressures ranging from saturation to 170 bar. A unique density float which operates on the principle of buoyancy was used for the measurements. Enthalpy, entropy and isothermal compressibility were then calculated from the experimental data and presented in a table. The statistical thermodynamic perturbation theory of Weeks, Chandler and Andersen was modified to improve the theoretical predictions at low densities. The modification involves the explicit accounting of the effects of the attractive part of the intermolecular potential on the pair correlation function. Comparison of the theory with the experimentally calculated configurational free energy and internal energy suggests that the Lennard-Jones 28,7 potential is more representative of the interaction of SF6 molecules than the Lennard-Jones 12,6. (Author)