Study of molecular interactions and ultrasonic velocity in mixtures of some alkanols with aqueous propylene glycol

210-220Ultrasonic velocity, density and viscosity are experimentally determined in the mixtures of methanol/ethanol with aqueous propylene glycol (4.5m and 1.5m) over entire range of composition at 303.15K. Several acoustic and thermodynamic parameters such as excess viscosity, excess adiabatic compressibility, excess free volume, excess molar volume, excess enthalpy, excess free length, viscous relaxation time have been calculated to study nature and extent of molecular interactions in these mixtures. Ultrasonic velocities theoretically evaluated using Nomoto’s relation, Van Dael and Vangeel’s ideal mixing relation, impedance relation, Jacobson’s equation, Rao’s specific sound velocity relation and Junjie’s equation are compared with experimental values to check applicability of these equations to the systems studied. The departure of experimental values of ultrasonic velocities from theoretical values is further analyzed to investigate molecular interactions. Two types of polynomial equations are fitted to experimental values of ultrasonic velocities. These polynomial representations of sound velocities have extremely small deviations from experimental values