A bifunctional and recyclable catalyst: Amine and ionic liquid grafting on MOFs for the one-pot synthesis of N-aryl oxazolidin-2-ones

Abstract

A bifunctional heterogeneous catalyst was designed and synthesized, denoted DMEDA/IL–NH2-MIL-101. The structure and physical-chemical characterization of DMEDA/IL–NH2-MIL-101 and its precursors were characterized by SEM, N2 adsorption-desorption, XPS, FT-IR, PXRD, elemental analysis, and TGA techniques. The date showed that the two catalytic components of N, N-dimethylethylenediamine (DMEDA) and 1-butyl-3-methylimidazolium bromide (BmimBr) were chemically immobilized in NH2-MIL-101 nanocages. The amine of DMEDA was grafted onto carrier NH2-MIL-101 by N–Cr coordinate covalent bonds and the ionic liquid of BmimBr (IL (Br−)) was anchored in the NH2-MIL-101 nanocages by ‘ship-in-a-bottle’ method, in which the amidogen of NH2-MIL-101 condensed with N, N-carbonyldiimidazole (CDI) firstly, and then alkylated with 1-bromo butane. This novel heterogeneous catalyst with two different active sites can efficiently catalyze the synthesis of N-aryl oxazolidin-2-ones from carbon dioxide (CO2), epoxides, and anilines in one-pot under mild solvent-free conditions. It not only showed good stability and recoverability after five cycles but also exhibited shape selectivity for the substrate due to the synergic catalysis of amine, ionic liquid, and NH2-MIL-101. This novel bifunctional material is a promising solid catalyst for the green synthesis of N-aryl oxazolidin-2-ones.

Keywords

• Metal-organic frameworks
• Ionic liquid immobilization
• N-aryl oxazolidin-2-ones
• One-pot synthesis
• Bifunctional heterogeneous catalyst