Compartmentalized Porosity in a Hydrogen-Bonded Organic Framework Enables High-Capacity C₃H₆/C₂H₄ Separation

Hydrogen-bonded organic frameworks (HOFs) are promising adsorbents for gas separation, yet capacity breakthroughs are frequently limited by a pore-architecture trade-off in which increased pore volume is accompanied by cavity expansion and weakened confinement. Herein, we report HOF-BUT-1, constructed from an unprecedented 8-connected linker, resulting in compartmentalized porosity. This HOF thus combines high porosity (pore volume = 0.95 cm³/g) with a small largest cavity diameter of 7.6 Å. Enabled by its balanced pore structure, HOF-BUT-1 exhibits a record-high propylene uptake of 8.83 mmol/g at 298 K and 1 bar, and thereby the highest separation potential (ΔQ) of 6.45 mmol/g for equimolar C₃H₆/C₂H₄ mixture among reported HOFs. Dynamic breakthrough experiments can deliver polymer-grade C₂H₄ (≥99.95%) and C₃H₆ (≥99.5%) with productivities of 4.79 and 2.88 mmol/g, respectively, and maintain performance over repeated cycles, demonstrating high potential for methanol-to-olefins products upgrading.