Thermodynamics Research Center / ThermoML | Thermochimica Acta

ABSTRACT

Excess molar enthalpies(Hm E) and excess molar volume(Vm E) at T=298.15 K for binary mixtures of {2.2.2-trifluoroethanol(TFE) + water or alcohols(methanol, ethanol, 1-propanol)} were obtained by calorimetry and densimetry. Excess molar enthalpies for the TFE + water system showed endothermic mixing, except for the low TFE concentration range (x1 less than 0.1) in which they showed exothermic one. On the other hand, excess molar volumes for this system were negative over the whole range of concentration. Excess molar enthalpies for all the (TFE + alcohol) systems were exothermic over the whole range of concentration and decrease in absolute value with increase of the carbon number of the alkyl group in the alcohol molecules(nC). Excess molar volumes were positive over the whole range of concentration and increase with nC. Moreover, we estimated excess partial molar enthalpy(Hm,i E,8) and volume(Vm,i E,8) at infinite dilution from the experimental results. These results were discussed qualitatively from the viewpoint of the intermolecular interactions in the pure component liquids and the mixtures.