Molecular interactions in binary mixtures of benzene with 1-alkanols (C5, C7, C8) at 35 °C:: An ultrasonic study

Densities and ultrasome speeds have been measured in binary mixtures of benzene with 1-pentanol, 1-heptanol and 1-octanol, and in the pure components, as a function of composition at 35 T. The isentropic compressibility, intermolecular free length, relative association, acoustic impedance, isothermal compressibility, thermal expansion coefficient, deviations in isentropic compressibility, excess free length, excess volume, deviations in ultrasonic speed, ex cess acoustic impedance, apparent molar compressibility, apparent molar volume, partial molar volume of 1-alkanol in benzene have been calculated from the experimental data of densities mid ultrasonic speeds. The variation of these parameters with composition indicates weak interaction between the component molecules and this interaction decreases in the order: 1-pentanol > 1-heptanol > 1-octanol. Further, theoretical values of ultrasonic speeds were evaluated using free length theory, collision factor theory, Nomoto's relation and Van Dael-Vangeel ideal mixing relation. The relative merits of these theories and relations were discussed for these system.