Dielectric constant of dimethyl sulfoxide-monohydric alcohol mixture solution at the microwave frequency

Dielectric spectra of dimethyl sulfoxide (DMSO)-monohydric alcohol (C1–C4) mixtures, over the entire mole fraction range, have been measured using the dielectric relaxation spectroscopy (DRS) at frequencies from 20 MHz to 20 GHz at room temperature. The mixture behavior is described according to four Davidson–Cole terms whose evolution with composition is analyzed. Numbers of hydrogen bonds and bonding energies between alcohol-alcohol and DMSO-alcohol pairs are estimated from the dielectric constants using the Luzar model. The average number of hydrogen bonds associated with DMSO decreases with increasing mole fraction of DMSO. The binding energy for alcohol-alcohol (E11) and DMSO-alcohol (E12) interactions decreases with the increased numbers of carbon atoms in the alcohols.