Unique low-molecular-weight lignin with high purity extracted from wood by deep eutectic solvents (DES): a source of lignin for valorization

Journal Article · Fri Jan 01 00:00:00 EST 2016 · Green Chemistry

DOI:https://doi.org/10.1039/C6GC01007E· OSTI ID:1328828

Alvarez-Vasco, Carlos; Ma, Ruoshui; Quintero, Melissa; Guo, Mond; Geleynse, Scott; Ramasamy, Karthikeyan K.; Wolcott, Michael; Zhang, Xiao

This paper reports a new method of applying Deep Eutectic Solvents (DES) for extracting lignin from woody biomass with high yield and high purity. DES mixtures prepared from Choline Chloride (ChCl) and four hydrogen-bond donors–acetic acid, lactic acid, levulinic acid and glycerol–were evaluated for treatment of hardwood (poplar) and softwood (D. fir). It was found that these DES treatments can selectively extract a significant amount of lignin from wood with high yields: 78% from poplar and 58% from D. fir. The extracted lignin has high purity (95%) with unique structural properties. We discover that DES can selectively cleave ether linkages in wood lignin and facilitate lignin removal from wood. The mechanism of DES cleavage of ether bonds between phenylpropane units was investigated. The results from this study demonstrate that DES is a promising solvent for wood delignification and the production of a new source of lignin with promising potential applications.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1328828
• Report Number(s): PNNL-SA-118851
• Journal Information: Green Chemistry, Vol. 18, Issue 19; ISSN 1463-9262
• Publisher: Royal Society of Chemistry
• Country of Publication: United States
• Language: English