Sustainable Routes for the Synthesis of Renewable Heteroatom-Containing Chemicals

One of the biggest discrepancies between the structure of many utilized chemicals and petrochemicals is the ubiquity of heteroatoms in the former and the lack thereof in the latter. Many commodity chemicals and almost all specialty chemicals and pharmaceuticals contain one or more heteroatoms, but introducing functionalities containing oxygen, nitrogen, sulfur or phosphorus into crude oil-derived chemicals is often a very energy- and resource-intensive endeavor. This and the inevitable depletion of fossil resources in the not too distant future are the main reasons for the development of sustainable ways to produce compounds bearing heteroatoms. Synthesis of oxygen-containing compounds from renewable resources such as starch, cellulose and hemicellulose is already well-known, and the production of phenolic compounds from lignin is garnering significant attention recently. In the meantime, there is a surge in the valorization of chitin from waste crustacean and insect shells for the production of various nitrogen-containing compounds. Much less explored is the valorization of sulfur- and phosphorus-containing biomass components, although they find some high market value applications. Catalysis plays a central role to enable the conversion of biomass into value-added products with high activity and selectivity. Further developments made by chemical engineers and process technologists will be required to make those processes economically feasible and competitive with current synthetic schemes from fossil resources. This perspective highlights the most recent advances and the upcoming challenges in the development of renewable and sustainable routes toward heteroatom-containing chemicals.