Excess Gibbs energy for binary mixtures of acetonitrile with acetic acid, propionic acid, isobutyric acid, and trimethylacetic acid
Total vapour pressures for binary mixtures containing acetic acid, propionic acid, isobutyric acid, and trimethylacetic acid with acetonitrile have been measured for the entire composition range at 298.15 and 318.15 K using a static manometric method. All systems show positive deviations from Raoult's law, enhanced by both an increase in temperature and an increase in the methylation of acetic acid. Activity coefficients have been calculated by taking into consideration the dimerization of these carboxylic acids in the vapour phase. TSE values obtained from GE and earlier reported HE values are found to be negative for acetic acid, about zero for propionic and isobutyric acids, and positive for trimethylacetic acid for the whole composition range. The results have been interpreted in terms of various contributions such as depolymerization, heteromolecular dipole–dipole interactions, and the increasing dimerization constant and steric hindrance with increase of complexity of the acid. Key words: excess Gibbs energy, carboxylic acids, acetonitrile, activity coefficients
Activity coefficients and excess Gibbs energy functions of acetophenone with 1,2-dichloroethane and 1,1,2,2-tetrachloroethane binary mixtures by using NRTL, UNIQUAC, UNIFAC and VAN LAAR models at a local atmospheric pressure of 95.3 kPa
