Thermodynamic characteristics of water-N-methylpyrrolidone mixtures and intermolecular interactions in them

Thermodynamic characteristics of water-N-methylpyrrolidone mixtures in the range 298.15-338.15 K were calculated from the data obtained in our previous studies and by other authors. The specific and nonspecific terms of the total energy of intermolecular interaction were determined within the framework of a model approach using the internal pressure as a measure of nonspecific interactions in a liquid. The parameters obtained indicate that, with an increase in the N-methylpyrrolidone concentration, the three-dimensional network of hydrogen bonds in water undergoes transformations and is broken. For the solutions differ in the type of intercomponent association and structural organization the boundaries of concentration ranges were determined.