Flexible Pillar-Linkers in Metal–Organic Frameworks for C2H2/CO2 and C2H2/C2H4 Separation

The development of dual-functional materials for C2H2/CO2 and C2H2/C2H4 separation is key to industrial technological breakthroughs in methane cracking to acetylene and naphtha/ethane steam cracking to ethylene. In response to the pain point of high energy consumption of traditional separation systems, we focus on the innovative design of metal–organic framework (MOF) materials and construct the UPC-198/199 system with pillared-layer structure. Precise regulation of the pore environment is achieved by unique structural interpenetration, which not only enhances the structure stability but also optimizes the separation selectivity by changing the framework density and the interaction sites of guest molecules. The introduction of flexible pillar-linkers effectively expands the interlayer space. Adsorption isotherms, molecular simulations, and breakthrough experiments show that UPC-198/199 can effectively separate C2H2/CO2 and C2H2/C2H4. This structural regulation strategy based on reticular chemistry provides a theoretical basis and material foundation for the development of the next generation of low-energy gas separation technology.