Compartmentalized Porosity in a Hydrogen‐Bonded Organic Framework Enables High‐Capacity C 3 H 6 /C 2 H 4 Separation

ABSTRACT 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 cm 3 /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 (Δ Q ) of 6.45 mmol/g for equimolar C 3 H 6 /C 2 H 4 mixture among reported HOFs. Dynamic breakthrough experiments can deliver polymer‐grade C 2 H 4 (≥99.95%) and C 3 H 6 (≥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.