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

Abstract

The reaction mechanism of ClO (Formula presented.) -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 (Formula presented.), was displayed, with an effect of the pH and reagent molar ratios. The involvement of HOCl and Cl (Formula presented.), 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.