Criteria for the elimination of azeotrope of a solvent mixture by a dissolved solute

Abstract

A function for determining the azeotropic composition of a given solvent mixture was derived; it was found to give values in good agreement with reported experimental data for binary solvent systems with and without a dissolved solute. The function also provides a basis by which the conditions for complete elimination of the azeotrope of a binary solvent mixture by a dissolved solute can be related to the boiling point rise of the solvent components in the presence of the dissolved solute. The set of criteria obtained therefrom facilitates the selection of a suitable solute which would completely eliminate the azeotrope of the solvent mixture during the salt distillation process. It also provides an early indication of the suitability of salt distillation as a possible separation technique for a given azeotropic system. In the case of the selection of a solute for enhancing the relative volatility of a close-boiling mixture, the criteria help to avoid solutes that would result in the formation of an azeotrope. © 1990.