Measurement and correlation of liquid–liquid equilibrium data for the ternary systems tetrabutylammonium dicyanamide + 1-propanol/2-propanol + water at different temperatures

Abstract In this work the ionic liquid tetrabutylammonium dicyanamide ([N4,4,4,4][dca]) was selected as extraction solvent to separate 1-propanol (NPA) and 2-propanol (IPA) from their aqueous solutions. The experimental liquid-liquid equilibrium data for the ternary systems ([N4,4,4,4][dca] + NPA/IPA + H2O) were measured at 303.15, 308.15, 313.15 and 323.15 K and atmospheric pressure. The equilibrium data were correlated by the NRTL model, and the consistency of correlation parameters was checked. Furthermore, the extraction capability of [N4,4,4,4][dca] was evaluated using distribution coefficients and selectivities. These parameters, for the ternary systems studied, increase with decreasing temperature. This study shows that [N4,4,4,4][dca] is a promising solvent for the extraction of NPA and IPA from water.