Comparison of Deep Eutectic Solvents and Organic Solvent Effects on the Separation of Ternary Azeotropes by the Experimental Study and Molecular Simulation

Extractive distillation is often used to separate difficult separation systems so as to realize the recovery and utilization of resources in industry. Based on the separation of ethylene glycol (EG), isoamyl alcohol, and water, the separation of ternary azeotropic mixtures by extractive distillation was studied. The study of extraction mechanism is very important for solvent screening and molecular design. To compare the selectivity of solvents, the interaction energies between solvent–water, solvent–EG, and solvent–isoamyl alcohol were calculated by the quantum chemical method. Atoms in molecules, reduced density gradient, and electrostatic potential were used to study the microextraction mechanism of solvents in the water–EG–isoamyl alcohol system. In extractive distillation, vapor–liquid equilibrium (VLE) data is used as the basic data for designing and optimizing the process. In order to solve the problem of lack of VLE data between N,N-dimethylformamide, dimethyl sulfoxide, choline-based deep eutectic solvents, and azeotropes, the VLE experiment of the solvent and azeotrope system was carried out. In this work, the selectivity of different solvents was compared by the quantum chemical method, the microextraction mechanism of solvents was explored, and the lack of VLE experimental data was supplemented, which provided theoretical guidance for the selection and design of solvent molecules with excellent performance.