Sustainable lignin modifications and processing methods: green chemistry as the way forward

B. Jacobs, Y.W. Yao, I. Van Nieuwenhove, D. Sharma, G.J. Graulus, K. Bernaerts*, A. Verberckmoes*

*Corresponding author for this work

Research output: Contribution to journal(Systematic) Review article peer-review

Abstract

The anthropologic impact on climate has reached a critical level given that society relies on non-renewable fossil resources for energy. Thus, to alleviate this, lignins can play a key role in the transition from petroleum-based chemistry towards a more sustainable and green approach. The commercially available lignins are to a large extent technical lignins, which are obtained from the soda, Kraft or sulfite process, and to a lesser extent, lignins from biorefineries (i.e., organosolv and hydrolysis lignin). However, solely the incorporation of lignins at the application level is insufficient to improve sustainability and increase the greenness of processes. In this case, the path from lignin biomass to the final product should also be considered. Therefore, in this review, initially we present an adaptation of the CHEM21 metrics toolkit to assess the greenness of valorization strategies based on strategically chosen criteria. Subsequently, we present a detailed evaluation of different solvents, demonstrating the greenness of a wide variety of solvents, which will be beneficial to readers. In addition, it can be used as an instrument to design green ionic liquids that can be applied during the valorization of lignins. Furthermore, green lignin modification and depolymerization strategies (to increase the solubility, reactivity and processability and improve the structural uniformity and alter functionalities) are evaluated based on green chemistry principles considering the adapted CHEM21 metrics toolkit. Finally, the methods for processing lignins (i.e., blending and polymer synthesis) are assessed to determine if they can be considered sustainable approaches.
Original languageEnglish
Pages (from-to)2042-2086
Number of pages45
JournalGreen Chemistry
Volume25
Issue number6
Early online date1 Feb 2023
DOIs
Publication statusPublished - 20 Mar 2023

Keywords

  • DEEP EUTECTIC SOLVENTS
  • SOFTWOOD KRAFT LIGNIN
  • BASE-CATALYZED DEPOLYMERIZATION
  • MULTICRITERIA DECISION-ANALYSIS
  • ORGANOSOLV LIGNIN
  • IONIC LIQUIDS
  • FORMIC-ACID
  • OXIDATIVE DEPOLYMERIZATION
  • MODEL COMPOUNDS
  • CHEMICAL-MODIFICATION

Cite this