Temperature dependence of liquid–liquid equilibria in nonaqueous two–phase systems based on formamide

Abstract

The cloud–point method was used to determine temperatures located on the binodal surface for several nonaqueous two-phase systems containing formamide, and: {1–pentanol + NaBr} or {1–pentanol + NaNO3}, or {1–butanol + NaNO3}, or {1–butanol + D–sorbitol}, or {acetonitrile + D–fructose}. For comparison purposes, the measurements were made in the water + acetonitrile + D-fructose system. The measured temperatures ranged from about 0 to 90 °C. The experimental data were described by the NRTL model as well as through several empirical equations with the parameters depending on temperature. Finally, the paper discusses the advantages and disadvantages of individual solutions.