Isomeric C6 alkanes are high-quality raw materials for producing high octane gasoline. Among them, the octane number of di-branched C6 alkanes is significantly higher than that of mono-branched C6 alkanes. Therefore, efficient and economical separation of mono- and di-branched C6 alkanes has received widespread attention. Herein, ZIF-8 with mixed ligands (named as ZIF-8-IM) was successfully synthesized by exchanging some 2-methylimidazole (MIM) ligands in the framework of ZIF-8 with imidazole (IM), and the microstructure of ZIF-8-IM were analyzed from N₂ adsorption. Adsorption thermodynamic and kinetic properties of n-hexane (nHEX), 3-methylpentane (3MP) and 2,3-dimethylbutane (23DMB) on ZIF-8-IM were determined by IGA-100 intelligent weight analyzer. Column breakthrough experiments were carried out to confirm the separation performance of of 3MP/23DMB binary mixture and nHEX/3MP/23DMB ternary mixture on ZIF-8-IM and ZIF-8. Results show that the microporous structure of ZIF-8 is changed by ligand exchange, which means the most probable pore diameters at 1.08 nm and 1.34 nm of ZIF-8 are converted to 1.06 nm and 1.19 nm of ZIF-8-IM. The adsorption equilibrium and kinetic characteristics of mono-branched 3MP are significantly enhanced due to the microstructural changes in ZIF-8-IM. The equilibrium adsorption capacity of 3MP on ZIF-8-IM is 1.6 times that of 23DMB, and the diffusional time constant is 4–13 times that of 23DMB. By relying on the synergistic effect of thermodynamic and kinetic characteristics, efficient adsorption and separation of 3MP/23DMB mixtures can be achieved with a separation factor of 2.24 on ZIF-8-IM. In addition, ZIF-8-IM can also achieve clear separation of nHEX/3MP/23DMB ternary mixtures, obtaining individual nHEX, 3MP, and 23DMB products. The results of this study show excellent application prospects in the production of the raw materials for high octane gasoline and molecular oil refining processes.

异构C6烷烃是生产高辛烷值汽油的优质原料。其中，双支链C6烷烃的辛烷值明显高于单支链C6烷烃。因此，高效、经济地分离单支链和双支链 C6 烷烃受到了广泛关注。在此，通过将ZIF-8骨架中的一些2-甲基咪唑（MIM）配体与咪唑（IM）交换，成功合成了具有混合配体的ZIF-8（命名为ZIF-8-IM），以及ZIF-8的微观结构-IM 从 N ₂分析吸附。采用IGA-100智能重量分析仪测定了ZIF-8-IM吸附正己烷（nHEX）、3-甲基戊烷（3MP）和2,3-二甲基丁烷（23DMB）的热力学和动力学性质。进行柱突破实验以确认 3MP/23DMB 二元混合物和 nHEX/3MP/23DMB 三元混合物对 ZIF-8-IM 和 ZIF-8 的分离性能。结果表明，配体交换改变了 ZIF-8 的微孔结构，这意味着 ZIF-8 的 1.08 nm 和 1.34 nm 处最可能的孔径被转换为 ZIF-8-IM 的 1.06 nm 和 1.19 nm。由于 ZIF-8-IM 的微观结构变化，单支链 3MP 的吸附平衡和动力学特性显着增强。3MP在ZIF-8-IM上的平衡吸附量是23DMB的1.6倍，扩散时间常数是23DMB的4-13倍。依靠热力学和动力学特性的协同作用，可以实现3MP/23DMB混合物的高效吸附和分离，在ZIF-8-IM上的分离因子为2.24。此外，ZIF-8-IM 还可以实现 nHEX/3MP/23DMB 三元混合物的清晰分离，获得单独的 nHEX、3MP 和 23DMB 产物。该研究结果在高辛烷值汽油原料生产和分子油精炼过程中具有良好的应用前景。ZIF-8-IM 还可以实现 nHEX/3MP/23DMB 三元混合物的清晰分离，获得单独的 nHEX、3MP 和 23DMB 产物。该研究结果在高辛烷值汽油原料生产和分子油精炼过程中具有良好的应用前景。ZIF-8-IM 还可以实现 nHEX/3MP/23DMB 三元混合物的清晰分离，获得单独的 nHEX、3MP 和 23DMB 产物。该研究结果在高辛烷值汽油原料生产和分子油精炼过程中具有良好的应用前景。