Structural effects on various imidazolium–based ionic liquids (ILs) (i.e., [C][A], [C] = [EMIM]⁺, [BMIM]⁺, and [OMIM]⁺; [A] = [BF₄]^–, [PF₆]^–, and [Tf₂N]^–) suitability as drying agents for gas dehydration processes are explored from thermodynamic and dynamic insights by quantum chemistry (QC) calculations and molecular dynamics (MD) simulations. It is found that [EMIM][BF₄] is regarded as the most promising drying agent because it exhibits the lowest Henry’s law constant and highest diffusion coefficient of H₂O among all ILs. The microscopic mechanism at molecular level is revealed based on QC calculations and MD simulations, and the results demonstrate that the IL (i.e., [EMIM][BF₄]) simultaneously with the smallest cation and anion size corresponds to both the strongest hydrogen bond (HB) interaction of H₂O–anion and the strongest HB together with van der Waals interactions of H₂O–cation. This work provides a valuable guidance from viewpoint of thermodynamics and dynamics for developing and screening novel ILs for gas dehydration.

对各种咪唑基离子液体（IL）的结构影响（即[C] [A]，[C] = [EMIM] ⁺，[BMIM] ⁺和[OMIM] ⁺； [A] = [BF ₄ ] ^-，[PF ₆ ] ^- ，和[TF ₂ N] ^- ）适合作为气体脱水方法干燥剂从由量子化学（QC）的计算和分子动力学（MD）模拟热力学和动力学的见解探讨。发现[EMIM] [BF ₄ ]被认为是最有前途的干燥剂，因为它表现出最低的亨利定律常数和最高的H ₂扩散系数。在所有IL中为O。通过QC计算和MD模拟揭示了分子水平的微观机理，结果表明，同时具有最小阳离子和阴离子尺寸的IL（即[EMIM] [BF ₄ ]）同时对应于最强的氢键（ HB）H ₂ O-阴离子和最强的HB相互作用以及H ₂ O-阳离子的范德华相互作用。这项工作从热力学和动力学的角度为开发和筛选用于气体脱水的新型离子液体提供了有价值的指导。