Mesostructured nitrogen-rich C3N5 materials grafted with alkyl bromide for solvent-free and metal-free cycloaddition of CO2 to propylene carbonate

Catalytic transformation of CO2 with propylene oxide (PO) is a sustainable pathway for the synthesis of propylene carbonate (PC), and the design of efficient heterogeneous catalysts that can be operated under solvent- free reaction conditions is a hot research topic in both C1 chemistry and functional materials. Herein, a series of nitrogen-rich mesostuctured carbon nitride (mpg-C3N5) materials with tunable nitrogen contents were prepared by using 5-amino-1H-tetrazole as a novel precursor and then grafted with n-bromobutane. The characterization results revealed that mpg-C3N5 materials had mesoporous structures and large surface areas of 58-283 m2 & sdot;g-1, depending on the dosages of silica templates. The synthesized mpg-C3N5-Br materials contained abundant nitrogen-containing species and bromide anions. As a heterogeneous metal-free catalyst, mpg-C3N5-Br exhibited a high yield of PC (ca. 60 %) under solvent-free reaction conditions, much higher than the catalyst prepared by traditional precursors.