Investigation on molecular interactions of antibiotics in alcohols using volumetric and acoustic studies at different temperatures

Highlights: • Antibiotics in different alcohols are used to study their interactions in solutions. • Density and sound velocity for antibiotic solutions are measured at different temperatures. • Apparent molar volume and isentropic compressibility are used to calculate partial molar quantities. • Acoustical parameters are calculated and discussed in terms of solute–solute and solute–solvent interactions. - Abstract: The density and sound velocity for pure alcohols (methanol, ethanol, iso-propanol and n-butanol) and molal solutions of nitroimidazoles (metronidazole (MNZ) and dimetridazole (DMZ) have been measured at different temperatures (293.15–313.15 K). Different volumetric and acoustical parameters like apparent molar volume (V^ϕ), partial molar volume (VЛљ^ϕ), apparent molar isentropic compressibility (K^ϕ), partial molar isentropic compressibility (KЛљ^ϕ), hydration number (n_H), acoustic impedance (Z) and intermolecular free length (L_f) of antibiotic solutions were calculated from the experimental values of density and sound velocity. The derived values have been used to explore the solute–solute and solute–solvent interactions. The V^ϕ values are positive and K^ϕ values are negative in both antibiotics, indicative of strong solute–solvent interactions and closely packed structure of antibiotics in alcohols. The decreasing trend of L_f with increasing antibiotic concentration shows the presence of strong intermolecular interactions in solutions.