Facile Synthesis of Chitosan-ZnO-α-Fe2O3 as Hybrid Nanocatalyst and Their Application in Nitrothiopheneacetate Reduction and Cyclization of Aminothiopheneacetate

Abstract

In the present research work, two films of Chitosan-ZnO-α-Fe2O3 nanocatalyst were synthesized by sol gel method using ZnO and Fe2O3 in equimolar concentration along with chitosan. The synthesized catalysts were characterized by fourier-transform infrared spectroscopy, ultraviolet–visible spectroscopy (UV–Vis), X-ray diffraction, field emission scanning electron microscopy and energy dispersive X-ray spectroscopic methods. Morphological studies revealed spongy spherical shaped nanoparticles in both film (A and B) having nanoparticle size 25 nm and 39.5 nm. The synthesized films were employed as a catalyst for reduction of nitrothiophene acetate along with Fe/FeSO4 and the reaction completion was monitored by TLC and UV–Visible spectral analysis. The reduction yield was 79% and 88% respectively for both the film A and film B. Further, the cyclization of formed aminothiophene with trimethylaluminum lead to the formation of dihydrotheinopyrrolone, which was confirmed by liquid chromatography with mass spectral detector and proton nuclear magnetic resonance (1H-NMR) spectroscopic characterization techniques. Thus, the result indicates that the synthesized Chitosan-ZnO-α-Fe2O3 nanocatalysts are efficient over other traditional catalysts for effective reduction of nitro group.