Preparation of carboxyl group functionalized FDU-15 type materials for the cyclization of CO₂ with 2-aminophenol

The efficient and facile preparation of benzoxazole compounds is of great importance, as benzoxazole is an important structural unit in many biologically active natural products and pharmaceutical compounds. Herein, we report carboxyl functionalized FDU-type mesoporous polymers (COOH-MPs), prepared via the evaporation-induced self-assembly method, for the preparation of benzoxazoles through the cyclization of CO₂ with 2-aminophenol. The developed COOH-MPs were systematically characterized using small angle XRD, N₂ adsorption-desorption, scanning electron microscopy and transmission electron microscopy, Fourier transform infrared spectroscopy, ¹³C nuclear magnetic resonance and thermo-gravimetric analysis. This COOH-MP material exhibited high surface area, uniform pore size distribution and high thermal stability, showing excellent catalytic performance and reusability in the cyclization of CO₂ with 2-aminophenol, without any co-catalyst.