POLYAZEOTROPY IN ASSOCIATING SYSTEMS - THE 2-METHYLPROPYL ETHANOATE PLUS ETHANOIC ACID SYSTEM

Polyazeotropy in binary systems is a singular case of vapor-liquid equ ilibrium (VLE) where, at a given pressure or temperature, various azeo tropes of alternating deviations from ideality are observed. Multiple azeotropy can be observed in systems which strongly associate in the v apor phase. Vapor-liquid equilibrium was measured for the 2-methylprop yl ethanoate (1) + ethanoic acid (2) system at 390.15 K and 353.15 K. The system presents two azeotropes at 390.15 K and none at 353.15 K, t he polyazeotropic behavior at the higher temperature can be explained in terms of dimerization of ethanoic acid. The data were satisfactoril y correlated using excess models for associating mixtures and chemical theory for the treatment of the vapor phase.