Preparation of tin-modified mono-ammonium phosphate fertilizer and its application as heterogeneous catalyst in the benzimidazoles and benzothiazoles synthesis

Abstract

This work presents an efficient, easy and green method for the benzimidazoles and benzothiazoles synthesis by a condensation reaction of 1,2-diamino benzene and 2-amino thiophenol with various aromatic aldehydes using SnP2O7 as a new heterogeneous catalyst. This catalyst was prepared by adding MAP to the solution of SnCl2 and characterized by microscopic and spectroscopic methods namely X-ray diffraction, scanning electron microscopy and infrared which proved that the chemical structure of MAP has been modified when SnCl2 was added leading to the formation of SnP2O7. On the other hand, the reaction conditions were optimized namely the nature of the solvent and the mass of the catalyst. The high yields (85–97%) and very short reaction times (5–40 min) obtained for various benzimidazoles and benzothiazoles derivatives synthesis show that the new catalyst is very interesting because of its good catalytic activity and its reusability for at least five cycles without any degradation of its activity.