Eco-friendly and efficient modification of native hemicelluloses via click reactions

Abstract

This paper reports the functionalization of heterogeneous hemicelluloses from Tacuara cane using the “click reaction”. The synthesis was designed as a two-step strategy. The first step was the introduction of azido groups onto the backbone of hemicellulose by etherification of the natural polymer with 1-azido-2,3-epoxypropane to obtain HC-N3. In the second step, different terminal alkynes functionalized with aliphatic and aromatic groups were grafted onto HC-N3 by copper-catalyzed azide-alkyne cycloaddition (CuAAC). Hemicellulose-based products were obtained in high yields and further characterized using spectroscopic (NMR-1H and ATR-FTIR), thermal (TGA) and chromatographic techniques (HPAEC) evidencing that click chemistry is an attractive modification strategy to graft hemicellulose with different molecules through a triazole ring. This methodology was designed as a possible approach to valorise native hemicelluloses and to facilitate their use as a potential platform to support different reagents or biomolecules.