ASSOCIATION MODEL OF FLUIDS - PHASE-EQUILIBRIA AND EXCESS-ENTHALPIES IN ACID MIXTURES

The binary vapor-liquid and liquid-liquid equilibria and molar excess enthalpies of alkanoic acid mixtures are correlated well using a new a ssociated-solution model whose equilibrium constants are defined in te rms of the volume fractions of chemical species and using association parameters for dimerization of acid molecules calculated from the vapo r pressures of the pure acids. The model shows a good performance in p redicting ternary vapor-liquid equilibria of the acetic acid + toluene + n-heptane system, ternary liquid-liquid equilibria of alkanoic acid mixtures including water and a non-associated component, and ternary excess molar enthalpies of the acetic acid f methanol f tetrachloromet hane system from only binary parameters.