Volume 94 Issue 11 | p. 10 | Concentrates
Issue Date: March 14, 2016

Nickel catalyst converts tough plant lignin into valuable chemicals

Waste from the grass Miscanthus yields compounds useful in the flavor and fragrance industry
Department: Science & Technology
News Channels: Biological SCENE, Environmental SCENE, Organic SCENE
Keywords: biobased chemicals, lignin, Miscanthus, phenolics, flavors and fragrances, renewables
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Using a nickel catalyst, researchers converted lignin from Miscanthus grass into phenolic compounds, such as propylsyringol and ferulic acid methyl esters, that can be converted into valuable flavor and fragrance compounds.
Credit: Sponner/Shutterstock
Photo of a Miscanthus crop with structures of compounds that can be derived from lignin.
 
Using a nickel catalyst, researchers converted lignin from Miscanthus grass into phenolic compounds, such as propylsyringol and ferulic acid methyl esters, that can be converted into valuable flavor and fragrance compounds.
Credit: Sponner/Shutterstock

To make fuels and chemicals from biomass, producers typically use the sugar-containing cellulose components. But first they must remove the surrounding lignin, a hardy phenolic biopolymer that helps support plant structure. Researchers have been looking for viable methods to crack apart the lignin into useful chemical intermediates, with some success coming from using precious-metal catalysts. A new study shows that an inexpensive nickel catalyst can transform 68% of lignin from the grass Miscanthus into aromatic compounds, while preserving residual plant sugars for subsequent conversion to fuels and other chemicals (ACS Sustainable Chem. Eng. 2016, DOI: 10.1021/acssuschemeng.5b01776). Mahdi M. Abu-Omar of Purdue University and colleagues combine 1 g of milled Miscanthus with 45 mL of methanol in a reactor containing nickel dispersed on activated carbon. The researchers place the catalyst in a microporous stainless steel cage so that the nickel can contact phenolic oligomers that form as the lignin breaks apart under high pressure and temperature, while keeping the catalyst separate from the carbohydrate residue left behind by the reaction. The catalyst deoxygenates the oligomers, turning them into a range of compounds, including dihydroeugenol, propylsyringol, and ferulic acid methyl ester, which can be used to make vanillin, the principal component of vanilla flavoring. The team further treats the residue with an iron chloride catalyst to make furfural and levulinic acid—products that can be used to make biofuels or other chemicals.

 
Chemical & Engineering News
ISSN 0009-2347
Copyright © American Chemical Society

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