Excess molar enthalpies of ternary mixtures containing o-toluidine + tetrahydropyran with pyridine or isomeric picolines or benzene or toluene at 308.15 K

► The HijkE data of ternary mixtures have been measured over entire mole fraction at 308.15 K. ► The HijkE data have been fitted to Redlich-Kister equation to evaluate adjustable ternary parameters. ► The observed data have been analyzed in terms of Graph and Prigogine-Flory-Patterson theories. ► The HijkE values predicted by Graph theory compare well with their corresponding experimental values.