Pore-Window Partitions in Metal–Organic Frameworks for Highly Efficient Reversed Ethylene/Ethane Separations
Yongpeng Li, Shu‐Cong Fan, Guo-Tong Zhang, Quan‐Guo Zhai
Abstract
The development of paraffin-selective adsorbents is desirable but extremely challenging because adsorbents usually prefer olefin over paraffin. Herein, a new pore-window-partition strategy is proposed for the rational design of highly efficient paraffin-preferred metal–organic framework (MOF) adsorbents. The power of this strategy is demonstrated by stepwise installations of linear bidentate N-donor linkers into a prototype MOF (SNNU-201) to produce a series of partitional MOF adsorbents (SNNU-202–204). With continuous pore-window partitions from SNNU-201 to SNNU-204, the isosteric heat of adsorption can be tuned from −34.4 to −19.4 kJ mol–1 for ethylene and from −25.5 to −20.7 kJ mol–1 for ethane. Accordingly, partitional MOFs exhibit much higher ethane adsorption capacities, especially for SNNU-204 (104.6 cm3 g–1), representing nearly 4 times as much ethane as the prototypical counterpart (SNNU-201; 27.5 cm3 g–1) under ambient conditions. The C2H6/C2H4 ideal adsorbed solution theory selectivity, dynamic breakthrough experiments, and theoretical simulations further indicate that pore-window partition is a promising and universal strategy for the exploration of highly efficient paraffin-selective MOF adsorbents.