The selection of efficient and environmental extractants is essential for the sustainable development of extraction processes. Based on the conductor-like screening model for the segment activity coefficient (COSMO-SAC), three deep eutectic solvents (DESs) were screened from 1000 DESs for the separation of diethoxymethane (DEM) and ethanol (EA). Subsequently, the liquid–liquid equilibrium behavior of the DEM + EA + DES system at different temperatures was measured. The results show that benzyltrimethylammonium chloride/glycerol (BTACl/GLY) has the highest selectivity and benzyltrimethylammonium chloride/ethylene glycol (BTACl/EG) and tetraethylammonium chloride/ethylene glycol (TEACl/EG) have similar extraction performance. More importantly, the extraction performance of DESs reported in this work is stronger than that of the solvents already reported. Additionally, analysis of the separation mechanism by various quantum chemical methods revealed that the purification of DEM and EA mixtures is mainly ascribed to the difference in electrostatic forces between the solvent and DEM/EA. The result confirmed that solvents with small molecular structures and strong nucleophilic sites are more competitive in separating the mixtures.

选择高效环保的萃取剂对于萃取工艺的可持续发展至关重要。基于链段活性系数的类导体筛选模型 (COSMO-SAC)，从 1000 个 DES 中筛选出三种用于分离二乙氧基甲烷 (DEM) 和乙醇 (EA) 的低共熔溶剂 (DES)。随后，测量了 DEM + EA + DES 系统在不同温度下的液-液平衡行为。结果表明，苄基三甲基氯化铵/甘油（BTACl/GLY）的选择性最高，苄基三甲基氯化铵/乙二醇（BTACl/EG）和四乙基氯化铵/乙二醇（TEACl/EG）的提取性能相似。更重要的是，本工作中报道的 DES 的萃取性能强于已报道的溶剂。此外，通过各种量子化学方法对分离机制的分析表明，DEM 和 EA 混合物的纯化主要归因于溶剂和 DEM/EA 之间的静电力差异。结果证实，具有小分子结构和强亲核位点的溶剂在分离混合物时更具竞争力。