Catalytic Hydrogenolysis of Aryl Ethers: A Key Step in Lignin Valorization to Valuable Chemicals

Lignin is a robust biomacromolecule (or a polymer) that gives structural integrity to plants and constitutes 25-35% of the woody biomass. Lignin is inedible, barely used, and contains mostly aromatic building blocks. Because of these features, lignin is considered an important renewable feedstock for the production of fine chemicals (or fuels) and the only significant feedstock providing aromatic compounds. The C-O bonds of aryl ethers are the most abundant linkages in the framework of lignin. In this Perspective, the state-of-the-art of selective hydrogenolysis (HGL) of C-O bonds of aryl ethers is discussed. Particularly, progress made recently and ethers relevant to lignin valorization are reviewed.