Acetate-based ionic liquid immobilized Fe-MIL-101-NH2: A highly efficient heterogeneous catalyst for the conversion of CO2into oxazolidinones with N-aryl epoxy amines

A novel acetate-based ionic liquid immobilized metal organic frameworks catalyst, Fe-MIL-101-N(Bnme2)OAc, was synthesized using a straightforward ion exchange strategy. Initially, Fe-MIL-101-N(Bnme2)Br was prepared by condensing a quaternary ammonium salt ionic liquid (N(BzBnme2)Br) with Fe-MIL-101-NH2. Subsequently, the Br-ions were exchanged with OAc-ions from potassium acetate to produce the desired catalyst. The morphology, structure and physicochemical properties of the catalyst were comprehensively characterized by XRD, SEM, FT-IR, DRS UV−vis, TGA, BET, and EA, which confirmed both the successful preparation of the catalyst and the integrity of the MOFs framework. The heterogeneous catalyst Fe-MIL-101-N(Bnme2)OAc demonstrated high activity in catalyzing the reaction of N-aryl epoxy amines with CO2to form oxazolidinone compounds under optimal conditions (80 °C, 8 h, 1 mL of MeCN, 1.0 MPa CO2and 5 mg catalyst), achieving a yield of up to 99 % with almost no production of the by-product cyclic carbonate. Moreover, this catalyst displayed excellent recyclability and extensive substrate applicability, maintaining its catalytic activity for at least five consecutive uses. Substrates with various substituents also produced the corresponding oxazolidinone products in high yields.