Ionization of a covalent organic framework for catalyzing the cycloaddition reaction between epoxides and carbon dioxide

Covalent organic frameworks (COFs), with two dimensional (2D-) or three dimensional (3D-) structures, have accessible open channels or nanopores, with uniform sizes ranging from angstroms to nanometers and have emerged as an excellent and promising platform for designing catalysts or catalyst carriers. Herein, a 2D-COF grafted with a 1-alkyl-3-methylimidazolium-based ionic liquid (AMIMBr@H2P-DHPh COF) on the channel walls was synthesized and utilized as a highly efficient heterogeneous catalyst for the chemical fixation of CO2 via a reaction with epoxides under solvent-free and co-catalyst-free conditions. The as-synthesized AMIMBr@H2P-DHPh COF shows excellent catalytic activity in promoting the cycloaddition reactions between epoxide and CO2; the excellent catalytic activity was maintained for up to five cycles. Advantages like high porosity, functional versatility, easy modification of COFs, and high catalytic activity of ionic liquids, have been realized in a single material. (C) 2020, Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.