Experimental and mechanism study of separation of ethanol-ethyl tert-butyl ether with deep eutectic solvents based on molecular simulation

The effective separation of ethyl tert -butyl ether (ETBE) and ethanol (EtOH) azeotropes during the production of gasoline additive ETBE has far-reaching significance for resource recovery and sustainable development. This work first proposed using green and sustainable deep eutectic solvents (DESs) to separate ETBE-EtOH efficiently. As an analog of ionic liquids, DESs are environmentally friendly, low-cost, and biodegradable. Based on a method combining quantum chemical calculation, molecular dynamics simulation, and toxicity analysis, the separation performance and mechanism of candidate DESs were explored, and DESs with better separation effects were preliminarily screened out. Using an improved Rose vapor–liquid equilibrium (VLE) reactor, a VLE experiment was carried out on the screened entrainers and the EtOH and ETBE azeotropic system. The experimental results showed that the prepared choline chloride-propylene glycol can achieve better azeotropic separation. This study provides theoretical guidance for the solvent screening of DESs in the extractive distillation separation by combining molecular simulation with experiments.