THERMODYNAMICS OF LEWIS ACID-BASE MIXTURES

The associated perturbed-anisotropic-chain theory (APACT) has been applied to treat multicomponent mixtures, in which components exhibit Lewis acid-base interactions. Mixtures of amphoteric molecules (such as alcohols), acidic molecules (such as chloroform), and basic molecules (such as ketones) as well as nonassociating components (diluents) are treated. The acid-base version of the perturbed-anisotropic-chain theory (ABPACT) is a closed form equation of state that takes into account explicitly dispersion interactions, polar interactions, and hydrogen bonding interactions between components that self-associate or solvate. The equation fits binary VLE mixtures quite accurately. Calculated results also are compared with those obtained from the Peng-Robinson equation of state, UNIFAC and the original APACT. In all cases where there are mixtures of associating components, the ABPACT gives a better fit of experimental data than these other equations.