Densities, viscosities and speeds of sound of binary mixtures of ethyl benzoate with toluene, and isomeric chlorotoluenes at different temperatures

Abstract

Density (ρ) data for binary mixtures of ethyl benzoate (EB) with toluene (T), o-chlorotoluene (o-CT), m-chlorotoluene (m-CT) and p-chlorotoluene (p-CT) were measured as a function of mole fraction at temperatures 298.15, 303.15, 308.15 and 313.15K. Further, speeds of sound (u) and viscosity (η) data for the same binary mixtures were also measured as a function of mole fraction at temperatures 303.15 and 313.15K. From the experimental data, excess volume (VE), isentropic compressibility (κs), excess isentropic compressibility (κsE), deviation in viscosity (∆η), deviation in intermolecular free length (∆Lf), deviation in acoustic impedance (∆Z) and Gibb's free energy of activation of viscous flow (G⁎E) have been computed. The variations in these properties with composition for all the binary mixtures suggest that the dipole–dipole interactions, electron donor–acceptor interactions, n–π interactions and charge-transfer complex formation between ethyl benzoate with toluene and isomeric chlorotoluenes were observed. Excess volume (VE) and excess isentropic compressibilities (κsE) were found to be negative over the entire mole fraction range of ethyl benzoate indicating the presence of dipole–dipole interactions between the unlike molecules in the mixtures. The negative deviation in viscosity (∆η) values was attributed to mutual loss of specific interactions between unlike molecules. The excess/deviation parameters were compared with various theoretical models. The results were discussed in terms of molecular interactions present in these mixtures.