Imidazolium Ionic Liquid-Functionalized MIL-101(Cr) for the Cycloaddition of CO2 and Propylene Oxide to Propylene Carbonate

An ionic liquid-grafted catalyst, denoted as IL@MIL-101-NH 2 , was synthesized by introducing a novel functionalized bis-imidazolium ionic liquid containing carboxyl groups into the MIL-101-NH 2 (Cr) using a simple one-step method. The structural features of the catalyst were characterized by FT-IR, XRD, XPS, BET, SEM and so on, and its catalytic performance in the cycloaddition reaction of carbon dioxide (CO 2 ) with propylene oxide (PO) to propylene carbonate (PC) was investigated. The results demonstrated that IL@MIL-101-NH 2 exhibited excellent catalytic activity. Under the conditions of 110 °C, 2 MPa, 3 h, and a catalyst loading of 3.0 wt%, a PO conversion of 95.1% and a PC selectivity of 98.7% were achieved. The superior catalytic performance of IL@MIL-101-NH 2 was attributed to the synergistic effect among the Cr 3+ metal active centers, nucleophilic Br − species and hydrogen-bond-donating –COOH groups. In addition, the catalyst maintains good catalytic performance after four consecutive cycles, indicating its favorable stability and promising application potential. Graphical