Amidosulfonic acid supported on graphitic carbon nitride: novel and straightforward catalyst for Paal-Knorr pyrrole reaction under mild conditions

A novel heterogeneous acidic catalyst was prepared by in situ immobilization of amidosulfonic acid (NH2SO3H) on graphitic carbon nitride (g-C3N4) under hydrothermal conditions. The textural morphology of NH2SO3H/g-C3N4 nanocomposite was characterized via powder X-ray diffraction, FT-IR, TGA, EDX, and scanning electron microscopy. The spatial arrangement of the amidosulfonic acid on the surface of g-C3N4 leads to the construction of a unique solid acid structure, resulting in a substantial enhancement of catalytic activity toward a high efficient preparation of pyrroles by Paal-Knorr reaction. The reactions undergo completion readily with good to excellent yields, with simple purification in an environmentally friendly manner. The NH2SO3H/g-C3N4 nanocomposite can be readily recycled, and no noteworthy reduction in the catalytic activity detected after four runs. [GRAPHICS] .

Automated summary

A novel heterogeneous acidic catalyst was prepared by immobilizing amidosulfonic acid on graphitic carbon nitride, leading to a unique solid acid structure that enhanced catalytic activity for the high efficient preparation of pyrroles. The catalyst showed good to excellent yields with simple purification and maintained its activity after multiple cycles.