Concentration and temperature dependence of the refractive index of ethanol-water mixtures: Influence of intermolecular interactions

摘要

The temperature and concentration dependence of the refractive index, nD(x, T), in ethanol-water mixtures agrees with previous data in the ethanol-rich concentration range. The refractive index ver-sus concentration x determined at 20 °C shows the expected maximum at about 41 mol% water (22 mass%water). The temperature derivative of the refractive index, dnD/dT, shows anomalies at lower water con-centrations at about 10 mol% water but no anomaly at 41 mol% water. Both anoinalies are related tointermolecular interactions, the one in nD seems to be due to molecular segregation and cluster formationwhile the origin of the second one in dnD/dT is still not clear.