A Rigid, Stable, and Scalable Aliphatic MOF Adsorbent for Efficient C2H2/CO2 Separation with Record Acetylene Packing Density

Integrating separation parameters such as high adsorption capacity and selectivity, moderate adsorption enthalpy (Qst), along with industrial factors including cyclic stability, cost‐effectiveness, and scalability into a single adsorbent remains highly challenging due to inherent trade‐offs among these properties. Herein, we strategically leverage the coordination modes of aliphatic ligands to significantly enhance C2H2/CO2 separation performance. The structure flexibility and pore metrics are finely modulated by hydroxylated aliphatic acid (DLmal). As a result, the rigid Zn‐bpy‐DLmal exhibits an exceptional C2H2 adsorption capacity of 1.4 mmol g‐1 at 0.01 bar, high C2H2/CO2 selectivity (49), and moderate C2H2Qst value (38.4 kJ mol‐1). Notably, it achieves record‐high C2H2 packing densities of 347 g L‐1 at 0.01 bar and 747 g L‐1 at 0.5 bar. Furthermore, the scale‐up production of Zn‐bpy‐DLmal to kilogram quantities has been successfully achieved at an estimated cost of $74 per kg. Dynamic breakthrough experiments confirm its practical C2H2/CO2 separation performance with excellent cyclability under high flow rates and both dry and humid conditions. Moreover, two‐bed pressure swing adsorption simulations demonstrate a high‐purity C2H2 (>99%) yield of 14.64 mol with a recovery of 88.2% per cycle.