A Stable Layered Microporous MOF Assembled with Y–O Chains for Separation of MTO Products

Abstract

Benefiting from highly tunable pore environments, some metal–organic frameworks (MOFs) have recently shown promising prospects in the separation of methanol-to-olefin (MTO) products (mainly C 3 H 6 and C 2 H 4 ). However, the “trade-off” between gas storage capacity and selectivity always results in inefficient separation. In addition, poor stability of MOFs also limits practical separation applications. Herein, we have successfully assembled a layered Y-MOF ( FJI-W9 ) with bent diisophthalate ligands (H 4 L), Y–O chains, and 2-fluorobenzoic acids. As expected, FJI-W9 not only exhibits good chemical stability but also shows significant potential for C 3 H 6 /C 2 H 4 separation. For FJI-W9, the C 3 H 6 uptake at 298 K and 10 kPa is 63 cm 3 /g, and the IAST selectivity of FJI-W9 for C 3 H 6 /C 2 H 4 (V/V = 50/50) is calculated to be 20.5. To the best of our knowledge, both C 3 H 6 uptake and selectivity of FJI-W9 surpass most porous materials. GCMC simulation indicates that the special supramolecular binding sites in FJI-W9 have much stronger interactions with C 3 H 6 than C 2 H 4 molecules. More importantly, practical breakthrough experiments demonstrate that FJI-W9 can effectively separate C 3 H 6 /C 2 H 4 (50/50) mixtures, thus obtaining high-purity C 2 H 4 and C 3 H 6, respectively.