The advancement of the methanol-to-olefins (MTO) process has intensified the urgent demand for the efficient separation of high-purity ethylene (C2H4) and propylene (C3H6) from MTO products, which remains a formidable challenge. Herein, we report three isostructural pillar-layered metal–organic frameworks with optimized pore environments by synergistically refining the methyl site density and pore sizes. Among them, the dimethyl-functionalized Ni-DMBDC exhibits superior olefin purification performances, delivering record ethane (C2H6, 120.3 cm3 g–1 at 1.0 bar) and C3H6 (97.2 cm3 g–1 at 0.1 bar) uptakes at 298 K. Moreover, it achieves high C3H6/C2H4 (13.5) and C2H6/C2H4 (1.8) selectivity, outperforming most reported MOF adsorbents. Dynamic breakthrough experiments confirm the exceptional separation sufficiency of Ni-DMBDC for C3H6/C2H4 (50/50, v/v) gas mixture even at a high flow rate of 10.0 mL min–1, yielding 124.2 and 76.8 L kg–1 of high-purity C2H4 (99.9%) and C3H6 (99.5%) in a single adsorption–desorption cycle, respectively. Notably, high-purity C2H4 and C3H6 (99.5%) can be simultaneously produced from a ternary C2H4/C3H6/C2H6 mixture (50/20/7, v/v/v) via this one-step process. Computational simulations further reveal that the synergistic effect of abundant methyl/phenyl groups and accessible O sites in Ni-DMBDC facilitates multiple guest–host interactions for efficient MTO product separation.
Liu et al. (Tue,) studied this question.