A material that has long been treated mainly as an industrial waste product could become a valuable source of chemicals. Researchers have developed a new process that transforms one of the toughest forms of lignin into chemical building blocks used in products ranging from medicines to dyes and fertilisers.
The work, carried out by researchers at the US Department of Energy’s Lawrence Berkeley National Laboratory, focuses on kraft lignin, a complex material generated in large quantities by the pulp and paper industry. Scientists say their approach could make it easier to use this renewable material as an alternative source of chemicals traditionally derived from petroleum.
What is lignin?
Lignin is a natural polymer found in the cell walls of plants. It gives wood much of its strength and helps hold plant fibres together.
When wood is processed to make paper, large quantities of lignin are separated from the cellulose fibres. Around 100 million tonnes of lignin are produced globally each year, according to the Society of Chemical Industry, and much of it is currently burned to generate energy.
Scientists have long viewed lignin as a potentially valuable renewable resource. The problem is that its complicated molecular structure makes it difficult to break down and convert into specific chemicals.
Why is kraft lignin so difficult to use?
Not all lignin behaves in the same way.
The type produced during the kraft pulping process is particularly resistant to chemical processing. Its complex structure makes it challenging to separate into predictable molecules that can be used by the chemical industry.
This has limited the amount of lignin that can be turned into higher-value products.
The Berkeley Laboratory team set out to tackle exactly this problem.
Turning lignin into useful chemical building blocks
The researchers developed a process that converts kraft lignin into benzylamines, a family of compounds used in the manufacture of several products, including pharmaceutical ingredients, dyes, fertilisers and pesticides.
The researchers first converted lignin into smaller molecules known as alkyl guaiacols. These lignin-derived compounds were then transformed into phenolic benzylamines.
The process involved testing different alcohol solvents, including methanol, ethanol and isopropanol, together with formic acid and a ruthenium-on-carbon catalyst.
Among the combinations tested, methanol produced the strongest yields of the desired intermediate compounds.
Why this could reduce dependence on petroleum
Benzylamines are traditionally manufactured using benzyl chloride, a petroleum-derived chemical.
Producing petrochemical building blocks can require substantial energy and depends on fossil-based raw materials.
The new approach instead starts with lignin, which comes from biomass and is already generated as part of the paper-making process.
That means an industrial by-product could potentially become a feedstock for another part of the chemical industry.
From waste to a renewable resource
The research represents a broader idea known as biomass valorisation—finding higher-value uses for materials that would otherwise be burned, discarded or treated as low-value waste.
Instead of viewing lignin simply as something left over from paper production, scientists are investigating whether its carbon-rich structure can be converted into useful products.
This could help create additional value from existing industrial processes without requiring entirely new crops or raw materials.
Researchers also looked at economics
The team did not stop at demonstrating that the chemistry works.
Researchers worked with the Joint BioEnergy Institute to examine how the process might perform at larger scales.
Their analysis indicated that methanol was the most promising solvent for larger-scale production. The researchers also found that some catalytic additives did not improve benzylamine yields enough to justify their additional use in the process.
That economic consideration is important because a laboratory reaction does not automatically become a commercially viable technology.
What could happen next?
The researchers say their findings move lignin conversion closer to a practical and scalable manufacturing process.
Further development will be needed to determine how efficiently the approach can operate at industrial scale, how its costs compare with conventional chemical production and what environmental benefits can be achieved across the entire process.
If those challenges can be addressed, lignin could become a more important source of renewable chemical feedstocks.
A new future for an old industrial by-product
For decades, much of the lignin generated by the pulp and paper industry has been treated primarily as a source of energy.
The new research suggests there may be another option: turning this difficult material into useful chemical ingredients.
The significance of the work goes beyond lignin itself. It demonstrates how scientists are trying to redesign industrial chemistry around renewable carbon sources rather than relying exclusively on petroleum.
If the technology can be successfully scaled, a material once considered one of the toughest parts of biomass to process could become a valuable ingredient in the production of everyday chemicals and industrial products.
