PNNL

Abstract

We report the study of a liquid-like phase that is found in dilute NaCl aqueous solutions frozen at temperatures below the liquid-to-solid phase transition temperatures of H2O and NaC1-2H2O. The fractions of water and NaC1 in this sub-eutectic quasi-liquid phase were measured by NMR spectroscopy, and the experimental results compared to predictions derived from an equilibrium thermodynamic analysis. A numerical model derived from the NaC1 water phase diagram and freezing point depression curve was found to provide a quantitative description of the quasi-liquid fraction for data measured above the eutectic temperature. The relevance and application of these findings to the study of chemistry in polar regions are discussed.