Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2022 Jan 4;15(1):350.
doi: 10.3390/ma15010350.

Structural Analysis of Lignin-Based Furan Resin

Xuhai Zhu  1 , Bardo Bruijnaers  2 , Tainise V Lourençon  1 , Mikhail Balakshin  1
Affiliations

Structural Analysis of Lignin-Based Furan Resin

Xuhai Zhu et al. Materials (Basel). .

Abstract

The global "carbon emission peak" and "carbon neutrality" strategic goals promote us to replace current petroleum-based resin products with biomass-based resins. The use of technical lignins and hemicellulose-derived furfuryl alcohol in the production of biomass-based resins are among the most promising ways. Deep understanding of the resulting resin structure is a prerequisite for the optimization of biomass-based resins. Herein, a semiquantitative 2D HSQC NMR technique supplemented by the quantitative 31P NMR and methoxyl group wet chemistry analysis were employed for the structural elucidation of softwood kraft lignin-based furfuryl alcohol resin (LFA). The LFA was fractionated into water-insoluble (LFA-I) and soluble (LFA-S) parts. The analysis of methoxyl groups showed that the amount of lignin was 85 wt% and 44 wt% in LFA-I and LFA-S fractions, respectively. The HSQC spectra revealed the high diversity of linkages formed between lignin and poly FA (pFA). The HSQC and 31P results indicated the formation of new condensed structures, particularly at the 5-position of the aromatic ring. Esterification reactions between carboxyl groups of lignin and hydroxyl groups of pFA could also occur. Furthermore, it was suggested that lignin phenolic hydroxyl oxygen could attack an opened furan ring to form several aryl ethers structures. Therefore, the LFA resin was produced through crosslinking between lignin fragments and pFA chains.

Keywords: NMR; bio-based resin; furfuryl alcohol; lignin; structural analysis.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Different pathways for the self-polymerization of furfuryl alcohol: (a) formation of methylene linkage; (b) formation of dimethyl ether linkage; (c) formation of conjugated double-bond sequences; (d) formation of branching linkage; (e) Diels-Alder cycloaddition reaction; (f) formation of γ-diketone structures [18,19,20].
Figure 2
Figure 2
The scheme of fractionation of LFA resin for the structural analysis.
Figure 3
Figure 3
Material balance analysis for LFA resin.
Figure 4
Figure 4
Identified HSQC signals for newly formed structures in LFA fractions, (a) aliphatic region of LFA-I fraction, (b) aliphatic region of LFA-S fraction, (c) aromatic region of LFA-I fraction, (d) aromatic region of LFA-S fraction.
Figure 5
Figure 5
Hypothesized reaction between furfuryl alcohol and lignin (see text for details).
Figure 6
Figure 6
31P NMR spectra of the original KL and LFA bioresin fractions and the calculated values (mmol/g). a Uncon./Con. is the ratio between the amount of 5-free PhOH and 5-condensed PhOH.
Figure 7
Figure 7
HSQC spectra of LFA fractions overlaid with simulated CS for models M1–9, (a) aromatic region of LFA-I, (b) aromatic region of LFA-S, (c) aliphatic region of LFA-I, (d) aliphatic region of LFA-S.
Figure 8
Figure 8
Two-dimensional (2D) HSQC NMR spectra of KL and LFA fractions in DMSO-d6: side-chain region of KL (a), LFA-I (b) and LFA-S (c); aromatic region of KL (d), LFA-I (e), and LFA-S (f), the lev0 is the value of lowest contour level in the spectrum, the colored structures are used to show the main structural linkages in samples (nlev = 50, lev0 = 50, toplev = 100%).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Ragauskas A.J., Beckham G.T., Biddy M.J., Chandra R., Chen F., Davis M.F., Davison B.H., Dixon R.A., Gilna P., Keller M., et al. Lignin Valorization: Improving Lignin Processing in the Biorefinery. Sciences. 2014;344:1246843. doi: 10.1126/science.1246843. - DOI - PubMed
    1. Dessbesell L., Paleologou M., Leitch M., Pulkki R., Xu C. Global lignin supply overview and kraft lignin potential as an alternative for petroleum-based polymers. Renew. Sustain. Energy Rev. 2020;123:109768. doi: 10.1016/j.rser.2020.109768. - DOI
    1. Gürbüz E.I., Gallo J.M.R., Alonso D.M., Wettstein S.G., Lim W.Y., Dumesic J.A. Conversion of hemicellulose into furfural using solid acid catalysts in γ-valerolactone. Angew. Chem. Int. Ed. 2013;52:1270–1274. doi: 10.1002/anie.201207334. - DOI - PubMed
    1. Perez R.F., Fraga M.A. Hemicellulose-derived chemicals: One-step production of furfuryl alcohol from xylose. Green Chem. 2014;16:3942–3950. doi: 10.1039/C4GC00398E. - DOI
    1. Gardziella A. Furanharze. In: Woebcken W., editor. Kunststoff-Handbuch. 2nd ed. Volume 10. Carl Hanser Verlag; München, Germany: 1988. pp. 70–84.

LinkOut - more resources