Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

Densities, ?, ultrasonic speeds, u, and viscosities, ? of binary mixtures of toluene with acetonitrile (AN), propionitrile (PN) and butyronitrile (BN), including those of pure liquids are measured over the entire composition range at temperatures 298.15, 303.15 and 308.15 K, respectively. From these experimental data, excess intermolecular free length, View the MathML source, the deviations in ultrasonic speed, ?u, excess acoustic impedance, ZE and excess free energy of activation ?G*E are calculated. The variation of these excess parameters indicates the presence of specific interactions between toluene and AN/PN/BN molecules, and the interactions follow the order: AN greater than PN greater than BN, i.e., the toluene nitrile interaction decreases with increase in alkyl chain length. Moreover, the theoretical ultrasonic speeds are computed based on the scaled particle theory and compared with the experimentally measured values.