Separation of the mixture (isopropyl alcohol + diisopropyl ether + n-propanol): Entrainer selection, interaction exploration and vapour-liquid equilibrium measurements

• Published in: The Journal of chemical thermodynamics 2019-08, Vol.135, p.27-34
• Main Authors: Zhang, Yi, Diao, Baotao, Xu, Dongmei, Jiang, Haihua, Zhang, Lianzheng, Gao, Jun, Wang, Yinglong
• Format: Article
• Language: English
• Subjects: Azeotrope; Diisopropyl ether; Isopropyl alcohol; Separation; Vapour-liquid equilibrium
• ISSN: 0021-9614; 1096-3626
• DOI: 10.1016/j.jct.2019.03.018

•PGEE was selected as extractant to separate the mixture of IPA + DIPE + NPA.•The charge density surface and the interaction energies were calculated to explore the interaction mechanism.•The VLE data for the systems IPA + PGEE, DIPE + PGEE and NPA + PGEE were measured and correlated.•An extractive distillation process for separating the mixture IPA + DIPE + NPA was proposed. For separation of the mixture {isopropyl alcohol (IPA) + diisopropyl ether (DIPE) + n-propanol (NPA)} by extractive distillation, propylene glycol ethyl ether (PGEE) was used as an entrainer based on selectivity since isopropyl alcohol + diisopropyl ether can an azeotrope. To explore the interaction mechanism between the entrainer PGEE and the components in the mixture, the charge density surface (σ-profiles) and the interaction energies were calculated based on the COSMO-SAC model and Dmol3, which could provide theoretical insight into interactions at the molecular level. Then, the data of isobaric vapour-liquid equilibrium (VLE) for (IPA + PGEE), (DIPE + PGEE) and (NPA + PGEE) systems were measured at 101.3 kPa. The NRTL, UNIQUAC and Wilson equations were applied to correlate the measured VLE data, and the thermodynamic model parameters for the binary systems were obtained by fitting the VLE data, which is helpful for the simulation and optimization of the separation process.