Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Vapor pressures of the 1-propanol + di-n-propylamine (DPA) system at six different temperatures between 293.15 and 318.15K were measured by a static method. The reduction of the experimental data to obtain molar excess Gibbs energies, GE was carried out according to Barker s method, assuming that GE is represented by a Redlich Kister equation. In the temperature range considered, the mixture shows azeotropic behaviour and negative deviation from the Raoult s law. DISQUAC describes better than the ERAS or UNIFAC (Dortmund version) models the experimental data. The analysis of the mixture structure in terms of the so-called concentration concentration structure factor, Scc(0) reveals that interactions between unlike molecules occur in such a way that several molecules of amine interact with one molecule of alcohol.