Cycloaddition of CO2 and epoxides over a porous covalent triazine-based polymer incorporated with Fe3O4

Abstract

A highly porous quaterphenyl-containing covalent triazine polymer (QP-CTP) incorporated with iron oxide nanoparticles (Fe₃O₄@QP-CTP) was synthesized and applied as a catalyst for the cycloaddition of CO₂ and epoxides under mild conditions. The synthesized materials were characterized using X-ray powder diffraction, N₂ adsorption–desorption isotherm, X-ray photoelectron spectroscopy, transmission electron microscopy, and elemental analysis. The Fe₃O₄@QP-CTP composite in the presence of tetrabutylammonium bromide showed 95% conversion of epoxides with high selectivity to cyclic carbonates at 50 °C, 0.1 MPa CO₂ in 12 h. The reaction kinetics was further improved upon increasing the temperature to 80 °C. The catalyst was easily recovered using a magnet, and its stability was confirmed using a recycle test, which showed that the catalyst could be re-used for a minimum of eight consecutive runs without a noticeable decline in catalytic activity. A plausible mechanistic pathway of the cycloaddition reaction over Fe₃O₄@QP-CTP was also proposed.