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Tom Welton is Professor of Sustainable Chemistry and Head of the Department of Chemistry. He has been working with postdoctoral researcher Agi Brandt and Jason Hallett, a research lecturer from the Department, to develop a process to break down wood to help the production of biofuels.
What have you invented?
We’ve developed a process that enables us to separate out the component parts of wood. Wood is made up of, in a roughly even split, cellulose, hemicellulose and lignin. Of these, cellulose and hemi-cellulose can be used in the production of biofuels; they can be converted through biological processes into sugars, and then alcohol.
How does your process work?
We use ionic liquids (salts in a liquid state) which are powerful solvents. They’re one of the few substances which can dissolve wood. Generally, using ionic liquids would result in something like a ‘wood soup’, which could then be processed, but the process steps require extreme operating conditions. What we’ve done is to use a specific ionic liquid which selectively dissolves the lignin in wood, leaving behind hemi- cellulose and cellulose.
Why is this useful?
Wood is potentially a useful source for biofuel, but it’s difficult to get at the cellulose and hemi-cellulose due to the lignin, which is very good at resisting the biological processes one would use to treat the wood to produce biofuels. Our method seeks to remove the lignin and leave behind the content that can be processed for biofuels, but also to retain the lignin, which is also potentially very useful.
How might lignin be useful?
Aromatic compounds, which are largely derived from coal and oil, are used in many applications, from polystyrene to pharmaceuticals. Because these will eventually run out, there need to be alternative sources. Lignin is the only biological material you can get aromatic compounds from so we’re currently conducting work aimed at deriving aromatic compounds from lignin.