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BACKGROUND: The tetrahydrofuran–ethanol azeotrope cannot be separated by common distillation, but can be effectively separated by extractive distillation. Extractive distillation can be simulated by Aspen Plus software. The minimum annual cost of the process can be calculated to assess ionic liquid separation ability. The interaction energy can be used to explain the separation mechanism. RESULTS: The non‐random two‐liquid model parameters of ternary mixtures for tetrahydrofuran and ethanol containing tributylmethylammonium acetate or 1‐octyl‐3‐methylimidazolium acetate were obtained. Thermodynamic property databases of tributylmethylammonium acetate, 1‐hexyl‐2,3‐dimethylimidazolium acetate and 1‐octyl‐3‐methylimidazolium acetate were established. Based on the thermodynamic model parameters and properties, the sequential iterative method was used to determine the best operating conditions and minimum total annual cost the of extractive distillation process. The interaction energy was calculated to explain the separation mechanism. CONCLUSIONS: The separation performance of tributylmethylammonium acetate is better than that of 1‐hexyl‐2,3‐dimethylimidazolium acetate or 1‐octyl‐3‐methylimidazolium acetate. The selection and design of the ionic liquids can be conducted in terms of the interaction energy. © 2023 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

BACKGROUND: The binary benzene–n‐propanol azeotrope can be formed in chemical production. Extractive distillation is an important azeotrope separation technology and an ionic liquid is a type of excellent entrainer. Aspen Plus software was used to simulate the extractive distillation process. The separation performance of ionic liquids was evaluated in terms of total annual cost of the extractive distillation process. The separation mechanism of the azeotrope was quantitatively explained using intermolecular interaction energy. RESULTS: The thermodynamic properties databases of 1‐octyl‐3‐methylimidazolium acetate, trioctylmethylammonium acetate and 1‐decyl‐3‐methylimidazolium acetate were established in Aspen Plus software. The extractive distillation process was established through combining the thermodynamic properties of the three ionic liquids and the vapor–liquid equilibrium data of benzene–n‐propanol–ionic liquid. The optimal operating conditions were obtained by minimizing the total annual cost of the separation process through a sequential iterative method. The interaction energy was calculated using density functional theory through Gaussian 09 software and used to explain the principle of the benzene–n‐propanol azeotropic system separation. CONCLUSIONS: 1‐Octyl‐3‐methylimidazolium acetate has the best separation performance among the three ionic liquids. The interaction energy can be used to screen and design ionic liquids in the process of benzene–n‐propanol extractive distillation separation. © 2021 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

• Isobaric VLE data of ternary for cyclohexane-ethanol containing IL ([N 1,8,8,8 [Ac], [DMIM][AC] or [C16MIM]) were determined at 101.3kPa. • Temperature dependence of some thermophysical properties (heat capacity, viscosity and density) of the three ILs were determined at 101.3kPa and 333.15-363.15 K. • The measured data were well correlated. Some important topics and issues related to possible extractive distillation separation of cyclohexane + ethanol system using ionic liquids (ILs) are presented in this manuscript. Three ILs with acetate anion (methyl-trioctyl-ammonium acetate [N 1,8,8,8 [Ac], 1-decyl-3-methyl-imidazolium acetate [DMIM][Ac] and 1-hexadecyl-3-methyl-imidazolium acetate [C 16 MIM][Ac]) were selected as entrainers. The vapor–liquid phase equilibrium (VLE) data for cyclohexane + ethanol + ILs system were determined at 101.3 kPa and correlated by Wilson and NRTL models. The separation effect of these ILs on the basis of the NRTL model follows this order: [N 1,8,8,8 [Ac] > [DMIM][Ac] > [C 16 MIM][Ac]. The binary VLE data of the cyclohexane-ethanol mixture obtained by this device were compared with previously published data and tested by the Herington thermodynamic consistency test. Temperature dependence of some thermophysical properties (density, viscosity and heat capacity) of these ILs were obtained and correlated within the range of possible distillation operating temperatures. [ABSTRACT FROM AUTHOR]