Separation of benzene and cyclohexane is essential for obtaining high-purity cyclohexane in the chemical industry and for resource recovery from exhaust gas, but is one of the most challenging separation processes due to their highly similar boiling points and kinetic diameters. Herein, based on the isoreticular contraction strategy, a novel covalent organic framework (i.e., HFPB-TAB-COF) with kgd topological structure and average pore size of 5.70 Å, between the kinetic diameters of benzene (5.60 Å) and cyclohexane (6.10 Å), is synthesized for benzene/cyclohexane separation by pore confinement effect. HFPB-TAB-COF has the highest ideal adsorbed solution theory (IAST) selectivity of 36.0 for benzene/cyclohexane separation, and can produce 0.48 mmol g⁻¹ cyclohexane with purity of +99% from 50:50 (v:v) benzene/cyclohexane mixture under dynamic condition, higher than reported separation materials. Optimizing the pore size of COFs by isoreticular contraction strategy can trigger the pore confinement effect for better meeting the separation challenge in industry.

中文翻译：

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一种新型 kgd 拓扑共价有机框架，具有最佳孔径，可实现苯/环己烷的高效分离


苯和环己烷的分离对于化工行业获得高纯度环己烷和从废气中回收资源至关重要，但由于它们的沸点和动力学直径高度相似，因此是最具挑战性的分离过程之一。在此，基于等网状收缩策略，合成了一种新型共价有机框架（即 HFPB-TAB-COF），具有 kgd 拓扑结构，平均孔径为 5.70 Å，介于苯 （5.60 Å） 和环己烷 （6.10 Å） 的动力学直径之间，用于通过孔限制效应分离苯/环己烷。HFPB-TAB-COF对苯/环己烷分离具有最高的理想吸附溶液理论（IAST）选择性，为36.0，在动态条件下，50：50 （v：v） 苯/环己烷混合物可生产纯度为 +99% 的 0.48 mmol ^g-1 环己烷，高于已报道的分离材料。通过等网状收缩策略优化 COF 的孔径可以触发孔隙限制效应，从而更好地应对工业中的分离挑战。