TEMPO-mediated oxidation of polysaccharides: survey of methods and applications

This review deals with TEMPO as a catalyst in oxidation of alcohol functions in polysaccharides. Synthesis of TEMPO and derivatives and the mechanism of the oxidative cycle in which TEMPO is involved in oxidation of alcohols are discussed. Results of oxidation of various polysaccharides with respect to yield, and introduction of the functional groups (aldehyde and/or carboxylate) are presented. Most of the primary oxidants are not ideal, as they produce large amounts of salts, e.g., sodium chloride from sodium hypochlorite. Results and perspectives are given to change the salt-based oxidative systems for much cleaner oxygen or hydrogen peroxide/enzyme-based TEMPO systems. Moreover, several immobilized TEMPO systems have been developed.