In the present work, three benzimidazole derivatives were synthesized by the reaction oo-phenylenediamine with 2-arylaldehydes with and without p-substituted electron-donating and electron-withdrawing groups using unmodified and modified cadmium oxide nanoparticles as heterogeneous catalysts. To the best of our knowledge, cadmium oxide nanoparticles have not been previously used for the synthesis of benzimidazoles. The influence of various experimental parameters, such as pH, reaction time, type and amount of catalyst, type of solvent on the reaction time was studied in detail. The structures of the synthesized benzimidazoles were characterized by NMR and FTIR spectroscopy. It was shown that the addition of a catalyst neutralizes the effect of the substituent nature on the percentage yield of the synthesis product. The effect of the substituent nature in aldehydes on the reaction time and the required mass of the nanosorbent was established. The advantages of the developed technique are an excellent yield of products (89-91%) and the possibility of catalyst recycling

doi.org/10.32737/0005-2531-2025-2-52-58