Efficient synthesis of benzimidazoles in solvent-free conditions using chitosan-copper (II) complex extracted from Persian Gulf shrimp shell

In this research, cheap, eco-friendly and reusable catalysis has been synthesized with a suitable method. For this purpose, firstly, chitosan particles were prepared through the process of deacetylation from Persian Gulf shrimp shell waste, and then the copper-based complex was successfully obtained on a bed of chitosan particles. The structure of chitosan-copper(II) complex was confirmed by using of various techniques such as Fourier transform infrared spectrometry analysis, X-ray diffraction, scanning electron microscopy, X-ray energy diffraction spectroscopy and visible-ultraviolet spectroscopy. Considering the wide application of benzimidazoles in industry and pharmaceuticals, the catalytic properties of the chitosan-copper(II) complex in the two-component reaction of the synthesis of various benzimidazole derivatives were studied under solvent-free conditions. The use of chitosan-copper(II) complex catalyst in the synthesis of benzimidazole derivatives showed several advantages, including significant efficiency, mild reaction conditions, short reaction time, easy separation of the catalyst and avoiding the production of toxic waste. Furthermore, the chitosan-copper(II) complex was easily recovered by filtration and could be reused for five cycles without loss of catalytic activity.