HIGH-PRESSURE NAPHTHALENE-XENON PHASE BEHAVIOR.

The high-pressure phase behavior of the naphthalene-xenon system is experimentally determined. Naphthalene solubility isotherms are obtained at 34. 9, 40. 0, and 45. 0 degree C over a range of pressures from 105 to 270 bar. The pressure-temperature projection of the solid-liquid-gas (SLG) line is obtained, and the upper critical end point (UCEP) is found at 46. 4 degree C, 136. 8 bar, and a naphthalene mole fraction of 0. 135. The location of the UCEP differs from a previously determined value; this discrepancy is attributed to differences in the experimental techniques used to obtain the UCEP. The phase diagram for the naphthalene-xenon system can be generated by using the Peng-Robinson and the Sanchez-Lacombe equations of state each with two mixture parameters fit to the LSG line.