Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

Molar excess enthalpies, HE m, at T = 298.15 K and atmospheric pressure have been measured using a microcalorimeter Tian-Calvet for the (methanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-octanol, or 1-decanol + dibutylether) systems. Experimental results have been compared with those obtained from the ERAS, DISQUAC, and Dortmund UNIFAC models. DISQUAC and ERAS yield similar HE m, results. Larger differences between experimental and calculated HE m, values are obtained from UNIFAC. ERAS represents quite accurately the excess molar volumes, VE m, of these systems. The excess molar internal energy at constant volume, UE V;m, is nearly constant for the solutions with the longer 1-alkanols. This points out that the different interactional contributions to this magnitude are counterbalanced. Interactions between unlike molecules are stronger in methanol systems. The same behaviour is observed in mixtures with dipropylether.