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.