Vapour-liquid equilibrium measurements and correlation for separating azeotropic mixture (ethyl acetate plus n-heptane) by extractive distillation

摘要

Since ethyl acetate and n-heptane can form the lowest azeotropic mixture, p-xylene and butyl butyrate were selected as extracting agents to separate the azeotrope (ethyl acetate + n-heptane) using extractive distillation. The binary isobaric vapour-liquid equilibrium (VLE) data for the binary systems (ethyl acetate + p-xylene), (ethyl acetate + butyl butyrate) and (n-heptane + butyl butyrate) were determined at 101.3 kPa using a Rose-Williams still. The measured experimental data were checked by the van Ness method and Herington test. Besides, the determined VLE data were fitted by the NRTL, UNIQUAC and Wilson thermodynamic models. The calculated root-mean-square deviation values of the temperature and vapour phase mole fraction are no more than 0.19 K and 0.0053, respectively. The results showed that three thermodynamic models can be used to correlate the determined experimental data for the three binary systems. Meanwhile, the binary interaction parameters for the three thermodynamic models were optimized, which are a great help for the optimization and simulation of separating the azeotropic mixture (ethyl acetate + n-heptane). (C) 2020 Elsevier Ltd.