Calorimetric measurement of the partial molar excess enthalpy at infinite dilution hiE,∞ and its meaning for the calculation of the concentration and temperature dependence of the molar excess enthalpy hE

Excess enthalpies of binary mixtures of non electrolytes in the highly diluted region were measured using an isoperibolic flow calorimeter. These data were used for the calculation of the partial molar excess enthalpy at infinite dilution, hiE,∞. In order to characterize the wide range of intermolecular interactions in binary solutions, a variety of solutes and solvents were examined. The temperature dependence of the partial molar excess enthalpy at infinite dilution was of special interest, so hiE,∞ was determined for the temperatures 283.15K, 298.15K, 323,15K, 343.15K and 363.15K at a pressure of 0.4MPa. er to minimize the experimental effort in obtaining the data base for the description of the concentration and temperature dependence of the molar excess enthalpy hE(x,T), a new method for finding the mathematical correlation with a minimum of information is introduced. The calculations are based on a modified second order Redlich-Kister equation.