Biomass fuel needs to deoxify.

• Position: Biorefineries

Biomass, which is useful as a supplement or replacement for petroleum, is processed in biorefineries and can be used as fuels or starting materials for the production of chemicals. However, the high oxygen content of many biomass components poses a problem. In the journal Angewandte Chemie, German researchers have introduced a process based on a tandem reaction that could reduce the oxygen content of both lignin and bio-oils under unusually mild conditions.

In principle, a biorefinery works like the petroleum version: a complex mixture of substances is separated into individual components and partially refined, chemically converted into other, more useful compounds. Lignin is one of the major components of biomass and is a by-product produced in large amounts by the paper and pulp industry. Even in the biorefineries, no better application than its use as solid fuel has been found so far.

Lignin is a heterogeneous group of phenolic macromolecules. Phenols are aromatic six-membered rings of carbon atoms with some number of alcohol (OH) functional groups. The depolymerization of lignin to form low-boiling arenas-oxygen-free aromatics--instead of high-boiling phenols would represent a great simplification of conventional refining processes.

However, phenolic OH groups are not so easy to cleave because the bond between the phenolic oxygen atom and the aromatic ring is very strong. Previous methods have been forced to...