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
. 2023 Dec 30;29(1):219.
doi: 10.3390/molecules29010219.

Study on the Relationship between the Structure and Pyrolysis Characteristics of Lignin Isolated from Eucalyptus, Pine, and Rice Straw through the Use of Deep Eutectic Solvent

Tengfei Li  1 , Xin Jin  1 , Xinyao Shen  1 , Hangdan Liu  1 , Ruiping Tong  1 , Xuzhen Qiu  1 , Junfei Xu  1
Affiliations

Study on the Relationship between the Structure and Pyrolysis Characteristics of Lignin Isolated from Eucalyptus, Pine, and Rice Straw through the Use of Deep Eutectic Solvent

Tengfei Li et al. Molecules. .

Abstract

Understanding the pyrolysis product distributions of deep eutectic solvent (DES)-isolated lignins (DESLs) from different types of biomass is of great significance for lignin valorization. The structure and pyrolysis properties of DESLs obtained from eucalyptus (E-DESL), pine (P-DESL), and rice straw (R-DESL) were studied through the use of various methods such as elemental analysis, GPC, HS-GC, and NMR techniques, and the pyrolysis characteristics and product distributions of the DESLs were also further investigated through the use of TGA, Py-GC/MS, and tubular furnace pyrolysis. DESLs with high purity (88.5-92.7%) can be efficiently separated from biomass while cellulose is retained. E-DESL has a relatively low molecular weight, and P-DESL has a relatively higher hydrogen-carbon effective ratio and a lower number of condensation structures. The Py-GC/MS results show that, during DESL pyrolysis, the monomeric aromatic hydrocarbons, p-hydroxyphenyl-type phenols, and catechol-type phenols are gradually released when the guaiacyl-type phenols and syringyl-type phenols decrease with the rising temperature. 4-methylguaiacol and 4-methylcatechol, derived from the guaiacyl-type structural units, are positively correlated with temperature, which causes a significant increase in products with a side-chain carbon number of 1 from P-DESL pyrolysis. 4-vinylphenol, as a representative product of the R-DESL, derived from p-hydroxyphenyl-type structural units, also gradually increased. In addition, the P-DESL produces more bio-oil during pyrolysis, while gases have the highest distribution in E-DESL pyrolysis. It is of great significance to study the characteristic product distribution of lignin isolated through the use of DES for lignin directional conversion into specific high-value aromatic compounds.

Keywords: deep eutectic solvent; lignin; molecular structure; phenolic compounds; pyrolysis.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflicts of interest.

Figures

Figure 1
Figure 1
The 2D 13C-1H (HSQC) spectra of the DESLs, and the chemical structure corresponding to each spectral peak.
Figure 2
Figure 2
Curves of TGA and DTG for the different DESLs.
Figure 3
Figure 3
Product distributions from the E-DESL, P-DESL, and R-DESL pyrolysis at different temperatures. (a): E-DESL pyrolysis products; (b): P-DESL pyrolysis products; (c): R-DESL pyrolysis products. G-phenols: guaiacyl-type phenols; S-phenols: syringyl-type phenols; H-phenols: p-hydroxyphenyl-type phenols; C-phenols: catechol-type phenols; MAHs: monomeric aromatic hydrocarbons.
Figure 4
Figure 4
The distributions of the main products from E-DESL, P-DESL, and R-DESL pyrolysis at different temperatures. (a) E-DESL pyrolysis products; (b) P-DESL pyrolysis products; (c) R-DESL pyrolysis products.
Figure 5
Figure 5
The carbon distribution of products from E-DESL, P-DESL and R-DESL pyrolysis under different temperatures.
Figure 6
Figure 6
The carbon number distributions of the longest side-chain of products from E-DESL, P-DESL, and R-DESL pyrolysis under different temperatures.
Figure 7
Figure 7
The yield of three-phase pyrolysis products from E-DESL, P-DESL, and R-DESL pyrolysis at different temperatures.
See this image and copyright information in PMC

References

    1. Bhatia S.K., Jagtap S.S., Bedekar A.A., Bhatia R.K., Rajendran K., Pugazhendhi A., Rao C.V., Atabani A.E., Kumar G., Yang Y.H. Renewable Biohydrogen Production from Lignocellulosic Biomass Using Fermentation and Integration of Systems with Other Energy Generation Technologies. Sci. Total Environ. 2021;765:144429. doi: 10.1016/j.scitotenv.2020.144429. - DOI - PubMed
    1. Yuan J.-M., Li H., Xiao L.-P., Wang T.-P., Ren W.-F., Lu Q., Sun R.-C. Valorization of lignin into phenolic compounds via fast pyrolysis: Impact of lignin structure. Fuel. 2022;319:123758. doi: 10.1016/j.fuel.2022.123758. - DOI
    1. Zhang X., Zhou Y., Xiong W., Wang P., Wei W., Ma J. Ex-situ catalytic microwave pyrolysis of alkali lignin facilitates the production of monophenols and monoaromatics under the application of LaFe1−xCuxO3 perovskites. Fuel. 2023;335:126987. doi: 10.1016/j.fuel.2022.126987. - DOI
    1. Chen S., Lu Q., Han W., Yan P., Wang H., Zhu W. Insights Into the Oxidation–Reduction Strategy for Lignin Conversion to High-Value Aromatics. Fuel. 2021;283:119333. doi: 10.1016/j.fuel.2020.119333. - DOI
    1. Dou Z., Zhang Z., Wang M. Self-Hydrogen Transfer Hydrogenolysis of Native Lignin Over Pd-PdO/TiO2. Appl. Catal. B-Environ. 2022;301:120767. doi: 10.1016/j.apcatb.2021.120767. - DOI

LinkOut - more resources