New Insights into Green Protocols for Oxidative Depolymerization of Lignin and Lignin Model Compounds.

Oxidative depolymerization of lignin is a hot topic in the field of biomass valorization. The most recent and green procedures have been herein detailed. Photochemical and electrochemical approaches are reviewed highlighting the pros and cons of each method. Mechanochemistry activated strategies are able to combine oxidation and depolymerization in the deconstruction of lignin. Homogenous and heterogeneous catalytic systems are exemplified stressing the green aspects associated with both the procedures. Solvent-free approaches as well as those carried out in alternative media are listed. Finally, the few examples of selenium catalyzed lignin valorization reported so far are cited.