Estimation of Some Excess Thermodynamic Functions of Liquid Mixtures from Ultrasonic Velocity and Density Data

摘要

During recent past it has been customary to utilize ultrasonic velocity and density data of liquid mixtures to estimate various thermodynamic properties. These properties are further employed to study various interactions occurring in the systems. One of the very useful thermodynamic property is the isentropic compressibility which can not be determined by any experimental technique except ultrasonic velocity and density. One of the major problem in the theoretical estimation of thermodynamic properties from ultrasonic velocity and density data is the knowledge of thermal expansivity (a) and isothermal compressibility (β_T) which are the key parameters in thermodynamics. Recently[1-5], empirical relations for estimating a and β_T from ultrasonic velocity and density have been proposed and tested for various classes of pure liquids, binary and higher order mixtures. In the present work, these empirical relations are applied to one ternary, DIPE (1)+IPA (2) + water (3), and its two constituents binary, DIPE (1) + IPA(2) and IPA(1) + water (2) liquid mixtures. Ultrasonic velocity and density data for these mixtures were taken from literature[6]. Excess isentropic compressibility (β_s~E), excess isothermal compressibility (β_T~E) and excess thermal expansivity (α~E) are estimated from ultrasonic velocity and density data for the aforesaid mixtures.