Refractive Indexes of Binary Mixtures of Tetrahydrofuran with 1-Alkanols at 25°C and Temperature Dependence of n and ρ for the Pure Liquids

Refractive indexes at 25°C were measured for binary mixtures of tetrahydrofuran with 1-hexanol, 1-heptanol, 1-octanol, 1-nonanol, and 1-decanol. Densities, from which excess molar volumes were derived, were measured at the same temperature for the system tetrahydrofuran + 1-decanol. Refractive indexes and densities for the pure compounds were determined at 11 temperatures between 20 and 30°C. The thermal expansion coefficients and the temperature derivatives of the refractive index for these liquids were calculated at 25°C. The temperature dependence of the molar refraction was also examined. The contribution to the molar refraction of a CH₂ group was calculated as was the difference between contributions from CH₃ and CH₂OH groups. The change of molar refraction on mixing is d iscussed in terms of molecular interactions and alkyl chain length.