Huang Hengcong, Prasetyo Niko, Kajiwara Takashi, Gu Yifan, Jia Tao, Otake Ken-Ichi, Kitagawa Susumu, Li Fengting
College of Environmental Science and Engineering, Shanghai Institute of Pollution Control and Ecological Security, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Siping Rd 1239, 200092, Shanghai, China.
Institute for Integrated Cell-Material Sciences, Kyoto University Institute for Advanced Study, Kyoto University, Yoshida Ushinomiya-cho, Sakyo-ku, Kyoto, 606-8501, Japan.
Chem Asian J. 2025 Jan 2;20(1):e202400899. doi: 10.1002/asia.202400899. Epub 2024 Nov 12.
Effective separation of hexane (C6) isomers is critical for a variety of industrial applications but conventional distillation methods are energy-intensive. Adsorptive separations based on porous coordination polymers (PCPs) offer a promising alternative due to their exceptional porosity and tunable properties. However, there is still an urgent need to develop PCPs with high stability and separation performance. This study investigates how substituting a methyl (-CH) group with a trifluoromethyl (-CF) group can regulate pores and hydrophobicity in PCPs. This precise adjustment aims to enhance stability and improve the kinetic separation performance of hydrophobic C6 isomers by considering the size and hydrophobicity of the trifluoromethyl group. Two isostructural PCPs with pcu topology, PCP-CH3 and PCP-CF3, were synthesized to vary pore diameters and hydrophobicity based on the presence of -CH or -CF groups. PCP-CF3 showed greater stability in water compared to PCP-CH3. While PCP-CH3 had high adsorption capacities, it lacked selectivity, whereas PCP-CF3 demonstrated improved selectivity, particularly in excluding dibranched isomers. Dynamic column separation experiments revealed that PCP-CF3 could selectively adsorb linear and monobranched isomers over dibranched isomers at room temperature. These findings highlight the potential of fluorine-modified PCPs for efficient isomer separation and underscore the importance of stability improvement strategies.
己烷（C6）异构体的有效分离对于各种工业应用至关重要，但传统蒸馏方法能耗高。基于多孔配位聚合物（PCP）的吸附分离因其出色的孔隙率和可调节性能提供了一种有前景的替代方法。然而，仍迫切需要开发具有高稳定性和分离性能的PCP。本研究调查了用三氟甲基（-CF3）取代甲基（-CH3）基团如何调节PCP中的孔隙和疏水性。这种精确调节旨在通过考虑三氟甲基的大小和疏水性来提高稳定性并改善疏水性C6异构体的动力学分离性能。合成了两种具有pcu拓扑结构的同构PCP，即PCP-CH3和PCP-CF3，根据-CH3或-CF3基团的存在来改变孔径和疏水性。与PCP-CH3相比，PCP-CF3在水中表现出更高的稳定性。虽然PCP-CH3具有高吸附容量，但缺乏选择性，而PCP-CF3表现出改善的选择性，特别是在排除双支链异构体方面。动态柱分离实验表明，PCP-CF3在室温下可以选择性地吸附直链和单支链异构体而非双支链异构体。这些发现突出了氟改性PCP在高效异构体分离方面的潜力，并强调了稳定性改进策略的重要性。
