Study of acoustic parameters of proline in lecithin-ethanol mixture at varying temperature

Abstract

The solution behaviour of proline in lecithin-ethanol mixture as a function of temperature and composition have been investigated by measuring velocity of sound in conjunction with density at different temperature in the range 25-40°C at an interval of 5°C. Various acoustical parameters such as intermolecular free length (L_f), relative association (RA), specific acoustic impedance (z), relaxation time (t), sound velocity number (U), molar volume (V_m) and internal pressure (p_i) have been evaluated from velocity of sound, density and viscosity measurements. The intermolecular free length (L_f) varies linearly with the concentration of proline and increases with rise in temperature. The linear trend in L_f values with the concentration of proline has been supported by the trend obtained from t values. The excess values of these parameters have also been calculated and their trends of variation are discussed in terms of the presence of significant molecular interactions between the component molecules in the mixtures.