CuSO4 nanoparticles loaded on carboxymethylcellulose/polyaniline composites: A highly efficient catalyst with enhanced catalytic activity in the synthesis of propargylamines, benzofurans, and 1,2,3‐triazoles

Abstract A novel and efficient heterogeneous CuSO 4 nanoparticles (CuSO 4 NPs) immobilized on carboxymethylcellulose/polyaniline (CuSO 4 NPs@CMC/PANI) composites were prepared via one‐pot and one‐step interfacial oxidative polymerization of aniline with sodium carboxymethylcellulose (CMC) as soft template and CuSO 4 as catalyst. The in situ formed CuSO 4 NPs were dispersed uniformly and firmly on the resultant composites and stabilized by complexation with hydroxyl groups (─OH), carboxylate groups (─COO − ), nitrogen atoms, and delocalized π‐π conjugate benzenoid and quinoid moieties of CMC/PANI composites. The morphology, composition, and structure of the as‐fabricated composites were systematically characterized by X‐ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), thermogravimetric analysis (TGA), and derivative thermogravimetry (DTG) techniques. The CuSO 4 NPs@CMC/PANI composites were successfully applied as catalysts in aldehyde‐alkyne‐amine (A 3 ) coupling reactions, A 3 ‐cycloisomerization tandem reactions, and Cu‐catalyzed azide‐alkyne cycloaddition (CuAAC) reactions. All reactions proceeded smoothly and afforded the desired products in excellent yields. Moreover, no significant decrease in catalytic ability was observed in A 3 model reaction after 15 recycles, indicating CuSO 4 NPs@CMC/PANI composites exhibited easy separability and high reusability. Tolerance of wide scope of substrate, excellent catalytic activity, easy operation, recycling of catalyst, and environmental benign are the salient features of these catalytic process.