Vapor–Liquid Equilibrium Measurement of Limonene + Citronellal, Limonene + β-Citronellol, and Citronellal + β-Citronellol Binary Systems in Kaffir Lime Essential Oil at Vacuum Pressures

The isobaric vapor–liquid equilibrium data for limonene + citronellal, limonene + β-citronellol, and citronellal + β-citronellol binary systems at vacuum pressures of 20 and 40 kPa were obtained experimentally by using a simple static ebulliometer with a modified Glass Othmer-Still type. The apparatus was previously validated by using pure solutions at various pressures. Liquid and vapor phase samples were analyzed using gas chromatography to obtain the composition. The experimental results were tested for thermodynamic consistency using the L.W. Wisniak and Fredenslund method. The data were correlated using Wilson, NRTL, and UNIQUAC models to obtain the binary interaction parameters. The minimum average absolute deviations (AADs) T for the limonene + citronellal binary system at 20 kPa are 0.1 K, 0.1 K, and 0.1 K, and those at 40 kPa are 0.2 K, 0.5 K, and 0.2 K. However, the AADs T for the limonene + β-citronellol binary system at 20 kPa are 0.3 K, 0.3 K, and 0.3 K, and those at 40 kPa are 0.4 K, 0.5 K, and 0.4 K. In addition, the AADs T for the citronellal + β-citronellol binary system at 20 kPa are 0.1 K, 0.1 K, and 0.1 K, and those at 40 kPa are 0.3 K, 0.3 K, and 0.3 K.