Thermodynamics Research Center / ThermoML | Fluid Phase Equilibria

ABSTRACT

Infinite dilution activity coefficients (gamma) of C4-C6 isomeric n-alkyl ethanoates/ethyl alkanoates, namely ethyl ethanoate, propyl ethanoate, ethyl propanoate, butyl ethanoate, ethyl butanoate in water were measured at several temperatures in the range from (273 to 361) K. Most measurements were carried out by the inert gas stripping method, although other three headspace gas chromatography techniques were also employed. A comprehensive critical review is further presented of literature data on infinite diluition activity coefficients, infinite dilution partial molar excess enthalpies, and heat capacities of these aqueous solutes. For each ester, the data measured in this work together with those reported previously in the literature were correlated with a suitable model equation providing adequate simultaneous description of the equilibrium measurements and the calorimetric information. As a result, a recommended temperature dependence of gamma of superior accuracy was established. The consistency of recommended gamma(T) with literature data on mutual solubilities of esters and water was also demonstrated. Analogous recommendations were derived also for the temperature dependence of the Henry's law constants (KH). The variation with temperature and ester molecular structure of gamma , KH, and related energetic functions of ester dissolution and hydration was overviewed and briefly discussed. Furthermore, the performance of five predictive approaches to estimate gamma(T) of the aqueous esters was tested.