Bi-functionalized ionic liquid/metal-organic framework composite for low-concentration CO2 cycloaddition reaction under atmospheric pressure

Abstract

Functionalized ionic liquid-based composites possess good CO2 affinity and heterogeneous catalytic performance, which are promising materials for CO2 separation and conversion to alleviate greenhouse effect and promote carbon source utilization. Herein, a new bi-functionalized ionic liquid 1-(2-hydroxyl-ethyl)− 3-methoxyethyl-imidazolium bromide ([HeMOEim][Br])/ aluminum terephthalate [MIL-53(Al), MIL: Materials of Institute Lavoisier] composite was synthesized via vacuum impregnation strategy under the solvent-free condition. The crystal structure of the composite transformed into narrow pore phase and the morphology of MIL-53(Al) remained unchanged after incorporating [HeMOEim][Br]. The ideal CO2/N2 selectivity of the composite was 15.9 at 25 oC and 0.1 MPa and was superior to that of the pristine MIL-53(Al) (2.3). The catalytic activity of the composite for low-concentration CO2 cycloaddition was investigated without solvent and co-catalyst under atmospheric pressure. The yield of cyclopropyl carbonate reached up to 95.7 % at 130 oC with 4 wt% composite for 12 h, indicating that the material has the potential for the direct conversion of CO2 from flue gas to high-value products.