Rational design of pyrazole-carboxylate-based metal–organic frameworks for efficient C3H6/C2H4 separation from methanol-to-olefins products

The development of efficient adsorbents for the effective separation of C 3 H 6 /C 2 H 4 mixtures from methanol-to-olefins (MTO) products is critically important yet challenging. In this study, we report two pyrazole-carboxylate-based metal–organic frameworks (MOFs), Ni-PCA-BPY and its methyl-functionalized analogue Ni-MPC-BPY, specifically engineered for efficient C 3 H 6 /C 2 H 4 separation. Compared to Ni-PCA-BPY, the methyl substituents in Ni-MPC-BPY optimize the pore environment precisely, yielding superior C 3 H 6 separation. Adsorption isotherms and breakthrough experiments demonstrate that Ni-MPC-BPY achieves remarkably higher dynamic separation productivity and C 3 H 6 /C 2 H 4 selectivity. Computational simulations further elucidate that this enhanced separation performance originates from a synergistic effect between the tailored microporous structure and strong hydrogen bonding and van der Waals interactions at active sites that facilitate C 3 H 6 adsorption preferentially. This study highlights the potential of the rational design of functionalized MOFs as efficient adsorbents for the practical separation of C 3 H 6 /C 2 H 4 mixtures from industrial MTO products.