Phase diagram of liquid ozone-oxygen system

Abstract

Vapor pressure composition data for liquid ozone-oxygen mixtures were obtained at -195.5°, -183°, and -180°C. The vapor pressure isotherms were used to construct the boiling point-composition line at oneatmos pressure. The vapor pressure of pure liquid ozone defines an upper limit for the partial pressure of ozone in the vapor in equilibrium with boiling liquid. The vapor pressure of ozone-oxygen solutions deviates markedly from Raoult's law in a positive direction. It is suggested that the apparent boiling point maximum reported by Schumacher, which implies negative deviations, may be due to difficulties in analysis of ozone at high concentrations where it is subject to decomposition at ordinary temperatures. Liquid-liquid equilibrium data are reported which indicate -180°C as an upper bound for the consolute temperature. The region of two liquid phases extends from 9 to 91 percent ozone by weight at -195.5°C, 29.8 to 72.4 percent at -183°.