Refractive indices, densities and excess molar volumes of monoalcohols plus water

The refractive index, n (D) , and density, rho, of binary mixtures of monoalcohols + water, have been measured at a temperature of 298.15,K and atmospheric pressure. The variation of the refractive indices of these solutions has also been determined with temperature in the range T = (278.15 to 338.15) K and atmospheric pressure. A comparative study has been made of the refractive indices obtained experimentally and those calculated by means of the Lorentz-Lorenz [Theory of Electrons, Dover Phoenix (1952)] and Gladstone-Dale relations [Trans. R. Soc. London 148:887-902 (1858)]; in all cases, the Gladstone-Dale equation was seen to afford values similar to those obtained experimentally. Calculations have been made of the excess molar volumes, V-E, and the molar refraction deviations, Delta R, of these mixtures and the differences between the experimental values for refractive index and those obtained by means of the Gladstone-Dale equation. Values of V-E were compared with others in the literature. In all cases the V-E values were negative, and in all cases, except in the methanol + water, Delta R showed a maximum for x = 0.8.