Molecular insights into azeotrope separation in the methyl tert-butyl ether production process using ChCl-based deep eutectic solvents

Abstract

Deep eutectic solvents (DESs) were first applied in the azeotrope separation process for the production of methyl tert-butyl ether (MTBE). Quantum chemistry and molecular dynamics simulations were used to explore the interaction mechanism of ChCl-based DESs in the liquid–liquid extraction of the MTBE–methanol (MeOH) system. The results showed that the extraction of MeOH by DESs mainly depended on the Van der Waals interactions between Cl atoms in ChCl and H atoms in the MeOH hydroxyl group. Hydrogen bond donors also enhanced the extraction effect to a certain extent. Liquid-liquid equilibrium experiments were carried out for the three selected DESs, and the ideal separation effect was obtained. The complete separation process of the MTBE-MeOH system was developed based on experimental data. This work demonstrates the application of DESs in the MTBE-MEOH system and provides guidance for the selecting and analysis of other DES extractants for the separation of low-carbon alcohol systems.