TEMPO-oxidized-cellulose nanofibers-immobilized copper(II) foam as an efficient heterogeneous catalyst for the azide-alkyne reaction in water

Abstract

In this work, a new sustainable catalyst for the click chemistry copper-catalyzed [3 + 2] cycloaddition reaction of azides and alkynes (CuAAC) was developed. This sustainable approach relies on preparing cellulose nanofibers, which were naturally extracted then oxidized by TEMPO and loaded with copper(II) (Cu(II)-TOCNF) as bio-catalyst for CuAAC in water. The characterization and analysis of the prepared cellulose-based catalyst were performed by different techniques such as SEM, EDX, BET, FTIR, TGA, and AFM analysis. The Cu(II)-TOCNF catalyst was highly active in the CuAAC reaction of various organic azides with alkynes, resulting in the regioselective synthesis of pure 1,4-disubstituted 1,2,3-triazoles in water at room temperature. The reported catalyst has the advantages of being sustainably prepared from biopolymer support, additive-free, recoverable, and reused for at least four consecutive times without a significant loss of efficiency.