Scalable Synthesis of the Robust Ultramicroporous Metal-Organic Framework for Reinforced C₃H₆/C₃H₈ Separation

Separation of propylene (C₃H₆) from the propylene/propane (C₃H₈) mixture, one of the most significant while daunting industrial separation challenges, is primarily through traditional energy-intensive cryogenic distillation. Herein, we leverage pore engineering in pillared metal-organic frameworks (MOFs) (CPL-1, coordination pillared layer, L = pyrazine) to reinforce C₃H₆/C₃H₈ separation. The MOF-embedded functional group (CPL-1-CH₃, L = methylpyrazine) is suitable for sieving propylene from propane. Particularly, compared to CPL-1, CPL-1-CH₃ exhibits a larger C₃H₆/C₃H₈ uptake ratio, C₃H₆/C₃H₈ adsorption selectivity, and stronger binding affinity for C₃H₆, as evidenced by single component adsorption isotherms and the heat of adsorption calculations. The in-depth molecular study unveils multiple supramolecular interactions that favor C₃H₆ over C₃H₈. Breakthrough experiments prove that CPL-1-CH₃ could efficiently separate the C₃H₆/C₃H₈ mixture with different ratios. With its impressive adsorption difference, green synthesis method, and cost-effective production, CPL-1-CH₃ holds prospective for alkene/alkane separation. This study provides deep insights to construct and develop high-powered MOF materials to address intricate chemical separation challenges.