Liquid-Liquid Equilibrium Measurements and Interaction Explorations for Separation of Dimethyl Carbonate and Isopropyl Alcohol Using ChCl-Based Deep Eutectic Solvents

Deep eutectic solvents (DESs) were adopted to separatethe azeotropesof dimethyl carbonate (DMC) and isopropyl alcohol (IPA). Liquid-liquidequilibrium (LLE) data plays a crucial role in designing the separationprocess. Three appropriate DESs (choline chloride (ChCl)-Urea, ChCl-Glycerol(Gly), ChCl-Ethylene glycol (EG)) were selected using the COMSO model.Then, the LLE data of DMC-IPA-(ChCl-Urea), DMC-IPA-(ChCl-EG), andDMC-IPA-(ChCl-Gly) were obtained through experiments at 298.15 K under101.32 kPa, the binary interaction parameters were obtained by regressingthe LLE data by the nonrandom two-liquid (NRTL) model, and the GUI-Matlabwas adopted to verify the precision of the NRTL interaction parametersand the experimental data. Finally, the mechanism of formation ofthe combined structures (DES-IPA/DMC) was explored through ESP. Tofurther explore the extraction capacities of the selected DESs, theextraction mechanism of three DESs was revealed. The interactionsbetween DESs and IPA/DMC were explored through penetration distanceand AIM analysis; the calculation results showed that (ChCl-EG) hasthe best extraction capacity, which is consistent with the experimentalresults. The results of experimental and theoretical calculationsshowed that the DES could effectively separate DMC and IPA.