Vapor-Liquid Equilibria of sec-Butanol–Isobutanol, sec-Butanol–tert-Butanol, and Isobutanol–tert-Butanol Systems

Vapor-liquid equilibrium data are determined at 760 mm Hg for the binary systems sec-butanol-isobutanol, sec-butanol-tert-butanol, and isobutanol-tert-butanol. The first system behaves like an ideal solution, and the second presents small negative deviations from the ideal solution with activity coefficients that are well represented by a oneconstant Redllch-Kister equation. The third system leads to simple activity coefficients that are thermodynamically inconsistent because of homo- and heteroassociation of the different species. An explanation is provided that points to positive deviations from the ideal behavior.