Collect. Czech. Chem. Commun. 1999, 64, 1393-1411

Excess Enthalpy in the Systems Nitromethane-Water and Methyl tert-Butyl Ether-Water. Employing Data on Excess Enthalpy for Thermodynamic Description of Heterogeneous Systems

Karel Řeháka,*, Josef P. Nováka, Jana Konetznáa, Andreas Heintzb, Petr Voňkaa and Jaroslav Matouša

a Department of Physical Chemistry, Prague Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic
b Department of Physical Chemistry, University of Rostock, Hermannstr. 14, D-18051, Rostock, Germany


The excess enthalpies measured in nitromethane-water and methyl tert-butyl ether-water systems at several temperatures are given. The values of the excess enthalpy were determined in both the homogeneous and heterogeneous regions. It is shown how the data for the heterogeneous region can be included in the calculation of parameters of empirical relations for the excess Gibbs energy. It follows from these calculations that the relations for the excess Gibbs energy can be obtained on the basis of the excess enthalpy data measured at several temperatures if the data also cover the heterogeneous region.

Keywords: Excess enthalpy; Heterogeneous systems; Parameter calculations; Maximum likelihood method; Calorimetry; Chemical thermodynamics.