According to a report this past week by Omicron Technology Ltd., Chicago, Ill., USA, on their Phys.org website, there may be new possibilities on the horizon for processing lignin. Lignin, the report explains, is not a pretty sight—an oily, almost black sludge. In addition, it smells much worse than it looks.

 

Inspecting lignin, especially up close and with an unblocked nose, it's hard to believe that it is now being treated as a potentially important renewable source of valuable aromatic compounds for the chemical industry. Unfortunately, despite many years of attempts by teams of chemists from all over the world, they still have not managed to develop efficient methods of converting lignin.

 

Researchers are now a step closer to cheap solar biorefineries capable of processing lignin on an industrial scale using the new photocatalysts developed at the Institute of Physical Chemistry of the Polish Academy of Sciences (IPC PAS) in Warsaw, Poland, in cooperation with the Warsaw University of Technology and the University of Cordoba.

 

In nature, lignin is present primarily in wood, where it is responsible for wood's consistency and hardness. It is the reason why trees do not creep over the ground, but instead reach upwards of 100 ft. into the air. The lignin content of wood is typically from 10% to 40%, depending on the tree species (the species also affects the chemical composition of the lignin). Lignin is produced in large quantities during the manufacture of paper, as a waste product in the wood softening process. World reserves of lignin are huge and continuing to increase. The current estimate is 300 billion tons, so it is a raw material that is more ubiquitous than crude oil (whose reserves are approximately 230 billion tons).

 

"From the chemical point of view, lignin is a natural polymer with a very complex three-dimensional structure, constructed of, among others, many derivative aromatic compounds including those from various phenyl alcohols. This chemical richness makes lignin a potentially very interesting raw material for the chemical industry. Unfortunately, at the same time, this is its curse, because it is very difficult to develop chemical reactions that would efficiently transform lignin into a specific, single chemical compound, readily suitable for further processing," said Prof. Juan Carlos Colmenares (IPC PAS).

 

More information is available in the full article published online.