An MOF-Based Single-Molecule Propylene Nanotrap for Benchmark Propylene Capture from Ethylene
Jia‐Xin Wang, Tengfei Zhang, Jiyan Pei, Di Liu, Yubo Wang, Xiao‐Wen Gu, Guodong Qian, Bin Li
Abstract
High Resolution Image Download MS PowerPoint Slide Highly selective capture and separation of propylene (C 3 H 6 ) from ethylene (C 2 H 4 ) presents one of the most crucial processes to obtain pure C 2 H 4 in the petrochemical industry. The separation performance of current physisorbents is commonly limited by insufficient C 3 H 6 binding affinity, resulting in poor low-pressure C 3 H 6 uptakes or inadequate C 3 H 6 /C 2 H 4 selectivities. Herein, we realize a unique single-molecule C 3 H 6 nanotrap in an ultramicroporous MOF material (Co(pyz)[Pd(CN) 4 ], ZJU-74a-Pd), exhibiting the benchmark C 3 H 6 capture capacity at low-pressure regions. This MOF-based nanotrap features the sandwichlike strong multipoint binding sites and the perfect size match with C 3 H 6 molecules, providing an ultrastrong C 3 H 6 binding affinity with the maximal Q st value (55.8 kJ mol –1 ). This affords the nanotrap to exhibit one of the highest C 3 H 6 uptakes at low pressures (60.5 and 103.8 cm 3 cm –3 at 0.01 and 0.1 bar) and record-high C 3 H 6 /C 2 H 4 selectivity (23.4). Theoretical calculations reveal that the perfectly size-matched pore cavities combined with sandwichlike multibinding sites enable this single-molecule C 3 H 6 nanotrap to maximize the C 3 H 6 binding affinity, mainly accounting for its record low-pressure C 3 H 6 capture capacity and selectivity. Breakthrough experiments further confirm its excellent separation capacity for actual 1/99 and 50/50 C 3 H 6 /C 2 H 4 mixtures, affording the remarkably high pure C 2 H 4 productivities of 17.1 and 3.4 mol kg –1, respectively.