Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Excess molar enthalpies, data of {o-toluidine (i) + pyridine or a-, b-, or c-picoline (j)} binary mixtures at a temperature of 308.15 K; densities, speeds of sound, u of the same mixtures at a temperature of (298.15, 303.15, and 308.15) K have been measured over entire mole fraction range. The measured densities and speeds of sound data have been utilized to determine excess molar volumes and excess isentropic compressibilities of the investigated mixtures. The excess propertied data of the studied mixtures have been analyzed in term of (i) Graph theory and (ii) Prigogine-Flory-Patterson theory. Analysis of excess molar volume data in terms of Graph theory suggest that (i + j) mixtures are characterized by interaction between nitrogen and carbon atoms of pyridine or substituted pyridine (a-, b-, or c-picoline) with hydrogen atom and pi-electron cloud of aromatic ring of o-toluidine to form i; j molecular complex. The IR studies lend additional support to the proposed molecular entities in (i + j) mixtures. It has been observed that the excess properties values predicted by Graph theory compare well with their corresponding experimental values.