Ternary Liquid-Liquid Equilibria in a Few Nonaqueous Two-Phase Systems

The composition of coexisting phases for liquid-liquid and solid-liquid-liquid equilibria were measured at 298.2 and 313.2 K and under atmospheric pressure for the following systems: {sodium bromide + formamide + ethyl acetate}, {sodium thiocyanate + ethanol + (R)-limonene}, and {sodium thiocyanate + methanol + dibutyl ether}. These concentrations were determined mainly by chromatography and, for the first system, with the help of argentometric titration. The standard uncertainties in mole fractions varied between 0.001 and 0.008. The tie-line data were reproduced by the NRTL model with medium accuracy. Several empirical equations were used and tested to correlate binodal curves. The rational form of the equation, based on the liquid-liquid-solid tie-line, turned out to be the most adequate.