Separation of isopropyl alcohol and isopropyl ether with ionic liquids as extractant based on quantum chemical calculation and liquid-liquid equilibrium experiment

Abstract Ionic liquids (ILs) have been widely studied as potential substitutes for traditional solvents in the extraction process. However, most of the literatures only focus on obtaining the data of equilibrium experiments. This work presents a method combining computer calculation, experiment and process simulation. From the perspective of molecular calculation, the extraction mechanism is analyzed. σ-profile is obtained by COSMO-SAC, and according to σ-profile, the feasibility and rationality of the separation of isopropanol and isopropyl ether by liquid-liquid extraction with ILs as extractant are proved. The hydrogen-bonding interaction between ILs and IPA are determined by using quantum chemical calculation, including bond length, total charge density, deformation charge density. By calculating the intermolecular interaction energy between selected ILs and isopropyl alcohol, the extraction ability of different ILs is compared. The correctness of mechanism analysis is verified by liquid-liquid equilibrium experiment. The process is simulated by entering binary interaction parameters in Aspen Plus. By calculating TAC, the operating conditions under the minimum TAC are obtained. This paper provides a new theoretical guidance for the selection of extractants for separating azeotropes.