Studies on the physical properties of the Three-Liquid-Phase System of n-Hexane-ethanol-NaH2PO4-water

Abstract

The physical properties, density, viscosity, and refractive index of equilibrated phases of the Three-Liquid-Phase System (TLPS) formed by n-Hexane+ethanol+sodium dihydrogen phosphate (NaH₂PO₄) +water were determined at 303.15 K and analysed as a function of change in concentration of individual phase forming components. The ternary plots were plotted to locate the shift in three-phase region with variation in system components. It was observed that the increase in total concentration of both ethanol and NaH₂PO₄ in a system showed a reduction of density and viscosity in the middle phase and was found to increase in the top and bottom phases; however, the refractive index of all three phases was increased. The effect of change in concentration of n-Hexane was observed to be different, like the density and viscosity of top and middle phases were found to decrease with increasing concentration of n-Hexane, and both the properties were found to increase in the bottom phase. In contrast, the refractive index of the top and bottom phases decreased with increasing concentration of n-Hexane. The influence of tie line lengths (TLL), which indicates the equilibrium characteristics between the phases, on the interfacial tension between the phases was also studied.