Intermolecular interaction in binary mixtures of formamide with 2-alkoxyethanol at different temperatures: Optical and internal pressure study

摘要

The refractive indices (n_D) and density (ρ) of binary mixtures of formamide with 2-methoxyethanol and 2-ethoxyethanol have been measured over the whole composition range at 303.15, 313.15 and 323.15 K. The experimental values of refractive index and density data are used to calculate the molar refraction (R_m), reduced molar free volume (V_m/R_m), molecular radii (r) and internal pressure (P_(int)). The deviations of refractive index (Δn_D), molar refractions (ΔR_m), reduced molar free volumes Δ(V_m/R_m) and internal pressures (ΔP_(int)) have been also calculated. The variations of these parameters with composition and temperature of the mixtures are discussed in terms of molecular interactions due to physical, chemical and structural effects between the unlike molecules. The applicability of nine different refractive index mixing rules is tested against the experimentally measured values, and good agreement has been obtained.