HYDROGEN PEROXIDE AND ITS ANALOGUES: II. PHASE EQUILIBRIUM IN THE SYSTEM HYDROGEN PEROXIDE – WATER

Abstract

A precision freezing point apparatus with platinum resistance thermometer was used to investigate the system hydrogen peroxide – water over the whole concentration range. The freezing point of the purest sample of hydrogen peroxide obtained by repeated fractional crystallizations of a large quantity of 99.6% pure solution was found to be −0.461°C; that of the dihydrate was −52.10°C. The two eutectics occur at concentrations of 45.2% and 61.2% H2O2 and at temperatures of −52.4° and −56.5°C. respectively. Contrary to what has been reported previously, water and hydrogen peroxide do not form solid solutions together. This was proved conclusively by applying the technique of radioactive tracers to the 'wet residue' method of Schreinemakers.