nano kaolin-so3h as a new efficient and reusable catalyst for one-pot synthesis of 2,4,5-trisubstituted imidazoles under solvent-free conditions

Nano kaolin-so3h as a new reusable and green heterogeneous catalyst was prepared by reaction of kaolin nanoparticles with chlorosulfonic acid. this new type of solid acid which contains the properties of a lewis acid (al^3+) and a brønsted acid (so3h group), was characterized by ft-ir, xrd, sem, tem, xrf, eds and tga. nano kaolinso3h was used as a recoverable acidic heterogeneous catalyst for onepot synthesis of 2,4,5-trisubstituted imidazoles via three component condensation of 1,2-diketones, various aromatic aldehydes and ammonium acetate. short reaction time, simple workup, high yields, solvent-free conditions and environmental friendly catalyst are some advantages of this protocol.