Experimental Study and Modeling of the Refractive Indices in Binary and Ternary Mixtures of Water with Methanol, Ethanol and Propan-1-ol at 293.15 K

Refractive indices of ternary mixtures of water + methanol + (ethanol or propan-1-ol), (water or methanol) + ethanol + propan-1-ol and their binary mixtures have been measured at 293.15 K and at atmospheric pressure over the whole composition range. The refractive index deviations were calculated and fitted to the Redlich–Kister equation for binary mixtures, and the Cibulka equation for ternary mixtures. Furthermore, we demonstrate that the refractive index of the associated ternary mixtures can be estimated with relative errors from 0.036 to 0.861 % by using the several mixing rules and the refractive indices of the corresponding pure components. The behavior of refractive indices is associated with solvent–solvent interactions and the formation of clusters.