Isobaric Vapor–Liquid Equilibria for Binary Mixtures of Biomass-Derived Gamma-Valerolactone + 1,4-Pentanediol and 1,2-Ethanediol

Abstract

Both γ-valerolactone (GVL) and 1,4-pentanediol (1,4-PDO) can easily be obtained by the catalytic hydrogenation of the lignocellulosic-based platform chemical levulinic acid (LA). The catalytic production of 1,4-PDO from either LA or GVL could lead to the formation of a mixture containing both substances. Because of the efficient separation of these species, their corresponding vapor−liquid equilibrium (VLE) data are fundamentally important to design appropriate separation units, for example, distillation systems. First, the temperature-dependent vapor pressure of GVL was redetermined between 377.85−480.55 K, which was correlated by both three-parameter Antoine and Clark-Glew equations. The isobaric vapor−liquid equilibria (VLE) of GVL and 1,4-PDO were determined at reduced pressures (p = 50.7 and 10.1 kPa). In addition, the 1,2-ethanediol, as the simplest vicinal diol, was selected for comparison of the phase behavior of GVL with diols. The experimental data were screened by Wisniak's L−W thermodynamic consistency test and correlated with Wilson, NRTL, and UNIQUAC activity coefficient models. The latter were analyzed by the Van Nest test. The applied models were found suitable for representing the VLE data.