Vapour-liquid equilibrium of the ethanol–propanal system

Abstract

A Gibbs–Van Ness type apparatus for total vapour-pressure measurements of binary mixtures has been developed. Vapour–liquid equilibrium data for the ethanol–cyclohexane system at 298.15 K have been obtained and compared with previous literature data. Data reduction has been carried out by a modified Barker's method using a Padé approximant to describe to excess Gibbs energy. The vapour–liquid equilibrium data for the ethanol–propanal systems have been measured over the whole concentration range at 298.15, 308.15 and 318.15 K. These mixtures show negative deviations from ideality. The calculated values for the excess functions are large and negative, and the calculated values for the concentration–concentration correlation function are lower than ideal values. This experimental behaviour is analysed in terms of the UNIQUAC model and several versions of the UNIFAC model.