Supramolecular linker-directed assembly of a ‘trap-and-diffusion’ MOF for one-step purification of polymer-grade C2H4 from C2 hydrocarbons

ABSTRACT Simultaneously removing ethane (C2H6) and acetylene (C2H2) from ethylene (C2H4) streams is advantageous for industrial production yet remains challenging for physisorbents. Herein, we report a microporous metal–organic framework (MOF), NKM-47, that achieves one-step C2H4 purification. NKM-47 was designed via a supramolecular linker-directed assembly approach and features a ‘trap-and-diffusion’ porous architecture composed of orthogonally arranged molecular pockets and 1D channels. The N/O-rich molecular pockets selectively capture the smallest and largest C2 species (C2H2 and C2H6) while the channels permit preferential diffusion of medium-sized C2H4. NKM-47 enables one-step production of polymer-grade C2H4 (99.99% purity) from both binary and ternary C2 gas mixtures under ambient conditions. This study presents the first example of a trap-and-diffusion mechanism for C2 hydrocarbon separation in MOFs, enabling the single-step purification of C2H4 through the selective diffusion of a species with intermediate physicochemical properties.