Green Synthesis of 1H-Benzo[d]Imidazol-2-yl-4-(Aryldiazenyl)Phenol and Bis Benzo[d]Imidazoles Using Fe3O4@Silicapropyl@Vanillin/Thiamin Nanoparticles

Abstract

Fe3O4@Silicapropyl@Vanillin/Thiamin nanoparticles were synthesized by a simple immobilization method using cheap and natural materials. The nanocatalyst was analyzed by XRD, FT-IR, FE-SEM, TEM, VSM and TGA techniques and was applied as a new, effective and magnetically recoverable solid acid for the synthesis of azo-linked benzo[d]imidazoles or bis benzo[d]imidazoles via the reaction of corresponding aldehydes and 1,2-diaminobenzene in water as green solvent. At the end of reaction, the catalyst could be separated by filtration of mixture in the presence of an external magnet and recycled for 7 consecutive runs, without significant decrease in efficiency. This avenue for the synthesis of benzo[d]imidazoles has advantages such as simplicity in operation, and green aspect by avoiding toxic conventional catalysts and solvents.