Ultrasonic Studies of Copper Soap-urea Complexes Derived from Mustard and Soybean Oils

Abstract

Ultrasonic velocities and densities have been measured in ternary mixtures containing copper soap-urea complexes derived from mustard and soybean oils in 20% and 40% methanol-benzene mixture to assess the effect of polarity of solvent on the micellar features of surfactant. The studies suggest that predomination of benzene (higher percentage of non-polar solvent) plays a significant role in compacting the molecular organisation of the micelles. From these values, the ultrasonic velocity (u), the specific acoustic impedance (Z), adiabatic compressibility (β), intermolecular free length (L f), apparent molar compressibility (f k), molar sound velocity (R) and primary solvation number (S n) have been calculated. The data clearly indicate that the values of u, Z, S n and R increase whereas the values β and L f decrease consistently with increase in the soap complex concentration. The critical micelle concentration (CMC) has also been determined and it has been found that CMC is dependent on the composition of the solvent mixture and composition of the edible oil. The results have been analysed in terms of Masson's equation. The results have been explained on the basis of intermolecular interactions between solute and solvent molecules and effect of polarity and concentration were accessed on various acoustic parameters.