Dielectric Study of the Miscibility of Binary Liquids, One Being an Alcohol

A dielectric relaxation study has been made over a frequency range of 10⁶–10^–3 Hz in the supercooled liquid state of the binary mixtures of 2-ethyl-1-hexanol (2EHOH) with a wide variety of common liquids. Differential scanning calorimetry measurements have also been made above 100 K. Our studies show compatibility of the methylcyclohexane with 2EHOH over the entire composition range. However, in the case of 1-bromobutane and acetone with 2EHOH, we have clearly seen two liquidlike phases separating out, which indicates incompatibility. In the case of 4-methyl-2-pentanol, the binary liquid shows no heterogeneity over most of the concentration range. In the case of methyl alcohol (MOH), the binary liquid shows some heterogeneity at a molecular level in the MOH-rich region. An attempt has been made to understand miscibility in terms of the preference for ring and chain formation among the alcohol molecules.