Special Aspects Of Fluid Solutions at High Pressures and Sub-And Supercritical Temperatures

Abstract

At high temperatures water substance looses its typical aqueous characteristics to a considerable extent and, at sufficiently high density, it becomes an almost “non-aqueous”, although highly polar and “water-like” solvent. Selected recent experimental examples are given. PVT-data and transport coefficients are shown and discussed. The dielectric constant of supercritical dense water is compared with analogous data for freons, methanol and other compounds. High pressure miscibility and critical curves of binary aqueous systems with nonpolar partners are discussed. Spectroscopic, particularly Raman measurements were made. Ion formation in pure water and in supercritical dilute and concentrated salt solutions is demonstrated by conductivity. The transition to fused salts is discussed. © 1981 IUPAC