Systematic Study on Physicochemical and Related Excess Properties of Several Binary Systems of Cyclic Ketones and Alkanediols (C₂–C₅)

The present study reports the measurements of permittivity, the refractive index, and density of eight polar binary systems containing four primary alkanediols (C₂–C₅) and two saturated and unsaturated cyclic ketones (cyclohexanone and isophorone) over the full composition range at T = 298.15 K and p = 0.1 MPa. Despite strong structural similarity of the cyclic ketones, isophorone molecules differ by a keto group conjugated with a CC double bond. The chosen primary alkanediols were 1,2-ethanediol, 1,3-propanediols, 1,4-butanediol, and 1,5-pentanediol, all containing two hydroxyl groups on the end of carbon skeletons. In this study, the role of intermolecular interactions and the constituent molecular structures on the dielectric, optical, volumetric, and structural properties of the binary liquid mixtures (cyclic ketones + alkanediols) were studied and analyzed with various approaches. The excess properties of different physical quantities confirm the formation of hydrogen-bonded structures in these mixtures. Negative excess permittivities were obtained for the studied systems, indicating a reduction of the number of effective dipoles in the binary mixtures.