| Abstract: | The thermodynamic activation parameters, enthalpies, ΔH?≠, free energies, ΔG ≠, and entropies, ΔS?≠, for viscous flow of the systems, water (W)?+?n-butylamine (NBA), W?+?sec-butylamine (SBA) and W?+?tert-butylamine (TBA), have been determined by using the density and the viscosity data. These properties and their excess values have been represented graphically against their composition. With respect to the composition, ΔG ≠ show a typical behaviour for all the systems – a fast rise in the water-rich region with a maximum followed by the values that decline up to the pure state of amines. The ΔH?≠ and ΔS?≠ versus composition curves follow the similar trend. For all systems the excess properties, ΔG ≠E, ΔH ?≠E and ΔS?≠E are characterized by sharp maxima in the water-rich region, which are thought to be mainly due to the hydrophobic hydration and the hydrophilic effect. |
