A Highly Stable Anion-Functionalized Cage-like Framework for Efficient Separation of MTO Products under Harsh Conditions

Separation of methanol-to-olefin products to obtain high-purity C₂H₄ and C₃H₆ has been deemed as one sustainable method for providing such indispensable industrial feedstocks. To meet the practical separation conditions, it is of critical significance to develop adsorbents that can separate C₃H₆/C₂H₄ under high-temperature and high-humidity conditions. Herein, we reported an anion-functionalized cage-like MOF (SIFSIX-Cu-TPA) showing a high-stability structure and huge distinction in C₃H₆ and C₂H₄ adsorption. Furthermore, C₃H₆- and C₂H₄-loaded single-crystal structures clearly reveal that more supramolecular interactions are generated between the C₃H₆ molecule and SIFSIX-Cu-TPA. Breakthrough experiments show that SIFSIX-Cu-TPA can efficiently separate C₃H₆/C₂H₄. After one separation cycle, 3.5 mol kg^–1 of high-purity C₂H₄ (>99.95%) and 2.5 mol kg^–1 of polymer-grade C₃H₆ (>99.5%) can be obtained from a C₃H₆/C₂H₄ (50/50) mixture at ₂98 K. More importantly, even at 338 K and 100% relative humidity, polymer-grade C₂H₄ (2.7 mol kg^–1) and C₃H₆ (1.4 mol kg^–1) can also be collected.