Effect of Temperature on the Refractive Index of Aliphatic Hydroxilic Mixtures (C2–C3)

The refractive indices of mixtures of ethanol+(1-propanol, 2-propanol, 1,2- propanediol, and 1,3-propanediol) have been measured at temperatures of 288.15, 293.15, 298.15, and 303.15 K at atmospheric pressure. In this work, an analysis of the mixing properties gives valuable information on packing trends, showing the iInteractions of ethanol in a hydroxilic environment. From the measured refractive indices on mixing, the parameters of a set of analytical expressions, which represent the composition and temperature dependences of the derived property, are reported. The excess molar volumes are estimated using derivations of the Heller equation, which are dependent on the refractive indices on mixing; accurate values are obtained for the alcohol mixtures, using literature data. The effect of temperature on the mixing and derived properties is analyzed in terms of the relative position of hydroxyl groups, the alkyl chain length, and the available hydrogen-bond iInteractions between solute and solvent molecules.