Thermodynamic study of melting equilibria under pressure of a supercritical gas

✍ Scribed by J. de Swaan Arons; G. A. M. Diepen

• Publisher: Elsevier Science
• Year: 2010
• Tongue: English
• Weight: 279 KB
• Volume: 82
• Category: Article
• ISSN: 0165-0513
• DOI: 10.1002/recl.19630820308

✦ Synopsis

Abstract

The modified course of the melting curve of a single substance is discussed for the case where, at its melting point, it is subjected to pressure of a supercritical gas. Unlike the melting curve of the pure substance, the new melting curve represents a three‐phase equilibrium solid‐liquid‐gas (S‐L‐G).

In section I equations are given for the slope of the S‐L‐G‐curve at the triplepoint of the least volatile component in P‐x‐, P‐T‐ and T‐x‐projections respectively. As a test the slope dP/dT is calculated for the system ethylene‐naphthalene. Agreement with the experimental value is found to within 2 %.

In section II the derivation is given of an equation for the equilibrium liquid composition as a function of pressure and temperature, provided that the solvent behaves like an ideal solution. A calculation for the system ethylenenaphthalene gives an idea of the departure from ideality at high pressures. Finally, equations are given for calculating the P‐T‐x behaviour of the S‐L‐G‐curve in the vicinity of the triplepoint of the least volatile component.