Sulfonated highly ordered mesoporous graphitic carbon nitride as a super active heterogeneous solid acid catalyst for Biginelli reaction

Development of new eco-friendly organocatalysis is a fundamental field in the construction of sustainable future through the pursuit of greener chemical processes. Among organocatalysis, graphitic carbon nitride (g-C3N4) as a metal-free heterogeneous carbon-based catalyst with the advantages of excellent chemical stability, distinct physicochemical properties, high thermal stability, and narrow band gap (about 3.0 eV) has promising applications in many research fields including photocatalysis, fuel cells, heterogeneous catalysts, adsorbent, and sensors. Making carbon nitride into mesoporous structure is an efficient strategy for improving its catalytic activity, specific surface area, pore volume, and active sites. In this paper, highly ordered mesoporous graphitic carbon nitride (ompg-C3N4) has been successfully synthesized and its surface is functionalized by sulfonic acid. The catalyst (ompg-C3N4/SO3H) was characterized by FT-IR, XRD, FESEM, EDS, BET, and TGA analysis. The resulting heterogeneous organocatalyst showed superior catalytic activity in Biginelli reaction for the synthesis of dihydropyrimidinone derivatives in mild and environmentally benign conditions. This novel eco-friendly organocatalyst could be recycled at least five cycles for the synthesis of dihydropyrimidinones without a significant loss in activity, which is an important parameter of green synthesis.