Synthesis and properties of novel reusable nano-ordered KIT-5-N-sulfamic acid as a heterogeneous catalyst for solvent-free synthesis of 2,4,5-triaryl-1 H-imidazoles

A novel silica-bonded propyl-N-sulfamic acid nanocatalyst (NHSO₃H-KIT-5) supported on modified silica mesopore KIT-5 as an organic-inorganic hybrid with high specific surface area was successfully prepared. The 3-aminopropyltriethoxysilane (APTES) on KIT-5 was reacted with chlorosulfonic acid and accurately characterized by the FT-IR, XRD, SEM, EDAXS, and TGA techniques. This heterogeneous and recyclable catalyst catalyzed one pot, multicomponent condensation of benzil, aromatic aldehydes, and ammonium acetate in the presences of 0.05 g of nanocatalyst under solvent-free conditions to afford triaryl-imidazoles in excellent yields. This catalyst showed high catalytic activity under green conditions. This reaction was performed under open air conditions and required no special reaction conditions or chromatographic separation for purification.