Researchers at the University of Wisconsin – Madison (UW) developed a new method to convert lignin, an important component of biomass waste, into simple chemicals revealed a study published in the journal Nature. Prof. Shannon Stahl et al., developed a method for the depolymerization of oxidized lignin under mild conditions, with relatively low temperatures (110°C/230°F) and low pressures, in aqueous formic acid that
results in more than 60% yield of low-molecular-mass aromatics.
The initial oxygen treatment step (producing the oxidized lignin) was previously reported by Alireza Rahimi, a UW postdoctoral researcher and Stahl. Rahimi explored many different approaches to break down the lignin. The team tried various metals under acidic conditions, when it discovered that acid without metals gave the best result. “The oxidation step weakens the links
in the lignin chains. The acid then breaks the links. Under these conditions, the aromatics formed in significantly higher yields than anyone has observed previously,” said Rahimi. Josh Coon, a professor of chemistry and graduate student from Arne Ulbrich showed that the resulting product mixture closely matches the distribution of subunits in the natural lignin.