ClO2-Mediated Oxidation of the TEMPO Radical: Fundamental Considerations of the Catalytic System for the Oxidation of Cellulose Fibers

Laura Giraldo Isaza; Gérard Mortha; Nathalie Marlin; Florian Molton; Carole Duboc

doi:10.3390/molecules28186631

ClO₂-Mediated Oxidation of the TEMPO Radical: Fundamental Considerations of the Catalytic System for the Oxidation of Cellulose Fibers

Molecules. 2023 Sep 15;28(18):6631. doi: 10.3390/molecules28186631.

Authors

Laura Giraldo Isaza¹, Gérard Mortha¹, Nathalie Marlin¹, Florian Molton², Carole Duboc²

Affiliations

¹ Institute of Engineering, University Grenoble Alpes, CNRS, Grenoble INP, LGP2, F-38000 Grenoble, France.
² Department of Molecular Chemistry, University Grenoble Alpes, CNRS, DCM, F-38000 Grenoble, France.

Abstract

The reaction mechanism of ClO2-mediated TEMPO oxidation was investigated by EPR spectroscopy and UV-Vis spectroscopy in the context of an alternative TEMPO sequence for cellulose fiber oxidation. Without the presence of a cellulosic substrate, a reversibility between TEMPO and its oxidation product, TEMPO+, was displayed, with an effect of the pH and reagent molar ratios. The involvement of HOCl and Cl-, formed as byproducts in the oxidation mechanism, was also evidenced. Trapping HOCl partly inhibits the reaction, whereas adding methylglucoside, a cellulose model compound, inhibits the reversibility of the reaction to TEMPO.

Keywords: EPR spectroscopy; TEMPO oxidation; UV–Vis spectroscopy; chlorine dioxide.

Grants and funding

This research received no external funding.