Temperature-Induced Transformation of Phase Diagrams for Water–Oxyethylated Nonylphenol–MgCl2 Systems

Abstract

The scheme of temperature-dependent topologic transformations in water–oxyethylated nonylphenol–MgCl2 phase diagrams was proved experimentally. An immiscibility area appears in the homogeneous area; it is bounded by a looped binodal curve and expands as temperature rises. The monotectic equilibrium area appears when the binodal curve touches the salt solubility line. The increasing neonol oxyethylation leads to an increase in temperature at which the immiscibility area appears and in monotectic temperature, due to the increasing hydration of surfactant micelles. The elucidated trends and studied phase diagrams can serve to purposefully select components and optimize process parameters of extraction involving oxyethylated surfactants.