A Targeted Review on Lignin and Its Depolymerization Methodologies

Ankita Kumari; Jiaguang Zhang; Graham Pattison; Con Robert McElroy

doi:10.53941/npa.2026.100018

Abstract

The surge in demand for renewable energy and bio-based chemicals has heightened attention on lignocellulosic biomass as an alternative to fossil-derived resources. Lignin, a major component of lignocellulosic biomass, is not used to a sufficient extent despite its potential as a renewable resource for multiple important chemicals and biofuels. This survey examines extraction, characterisation, and decomposition of lignin, highlighting recent innovations and hurdles in lignin valorisation. Various lignin isolation techniques, such as kraft lignin, soda lignin, organosolv lignin, ionic liquids, hydrolysis lignin and deep eutectic solvents, are explored, emphasizing their impact on lignin purity and structural integrity. Analytical methods including NMR, FTIR, GPC, TGA, and DSC provide critical insights into lignin’s complex chemical structure and physicochemical properties. The review also investigates diverse depolymerisation strategies: acid-catalysed, base-catalysed, metal-catalysed, hydrogenolysis, electrocatalytic oxidative and reductive reaction pathways and microwave-assisted processes focusing on their efficiency, selectivity, and applicability for industrial-scale to convert lignin into value-added products. Despite technological advancements, problems such as lignin’s structural heterogeneity, high energy requirements for processing, low yields, and catalyst costs impede widespread commercialisation. Future research should address cost-effective, recyclable catalysts, process integration within biorefineries, and optimisation strategies to enhance economic feasibility. Advancing lignin valorisation technologies is vital for achieving a circular bioeconomy and reducing dependence on fossil-based resources.

References

1.
Chen, M.; Dai, W.; Wang, Y.; et al. Selective catalytic depolymerization of lignin to guaiacols over Mo-Mn/sepiolite in supercritical ethanol. Fuel 2023, 333, 126365. https://doi.org/10.1016/j.fuel.2022.126365.
2.
Margellou, A.; Triantafyllidis, K. Catalytic transfer hydrogenolysis reactions for lignin valorization to fuels and chemicals. Catalysts 2019, 9, 43. https://doi.org/10.3390/catal9010043.
3.
Zakzeski, J.; Bruijnincx, P.C.A.; Jongerius, A.L.; et al. The catalytic valorization of lignin for the production of renewable chemicals. Chem. Rev. 2010, 110, 3552–3599. https://doi.org/10.1021/cr900354u.
4.
Ji, Q.; Yu, X.; Chen, L.; et al. Comprehensive depolymerization of lignin from lignocellulosic biomass: A review. Crit. Rev. Environ. Sci. Technol. 2023, 53, 1866–1887. https://doi.org/10.1080/10643389.2023.2190314.
5.
Roy, R. Characterization of Naturally Derived Polymer by Oxidative, Thermal, and Spectrometric Methods. Ph.D. Thesis, South Dakota State University, Brookings, SD, USA, 2020.
6.
Koutsianitis, D.; Mitani, C.; Giagli, K.; et al. Properties of ultrasound extracted bicomponent lignocellulose thin films. Ultrason. Sonochemistry 2015, 23, 148–155.
7.
Pardo Cuervo, O.H.; Rosas, C.A.; Romanelli, G.P. Valorization of residual lignocellulosic biomass in South America: A review. Environ. Sci. Pollut. Res. 2024, 31, 44575–44607. https://doi.org/10.1007/s11356-024-33968-6.
8.
Cheng, F.; Zhao, X.; Hu, Y. Lignocellulosic biomass delignification using aqueous alcohol solutions with the catalysis of acidic ionic liquids: A comparison study of solvents. Bioresour. Technol. 2018, 249, 969–975. https://doi.org/10.1016/j.biortech.2017.10.089.
9.
Hassan, S.S.; Williams, G.A.; Jaiswal, A.K. Emerging technologies for the pretreatment of lignocellulosic biomass. Bioresour. Technol. 2018, 262, 310–318. https://doi.org/10.1016/j.biortech.2018.04.099.
10.
Ashokkumar, V.; Venkatkarthick, R.; Jayashree, S.; et al. Recent advances in lignocellulosic biomass for biofuels and value-added bioproducts—A critical review. Bioresour. Technol. 2022, 344, 126195. https://doi.org/10.1016/j.biortech.2021.126195.
11.
Raud, M.; Kikas, T.; Sippula, O.; et al. Potentials and challenges in lignocellulosic biofuel production technology. Renew. Sustain. Energy Rev. 2019, 111, 44–56. https://doi.org/10.1016/j.rser.2019.05.020.
12.
Agbor, V.B.; Cicek, N.; Sparling, R.; et al. Biomass pretreatment: Fundamentals toward application. Biotechnol. Adv. 2011, 29, 675–685. https://doi.org/10.1016/j.biotechadv.2011.05.005.
13.
Gregg, J.S.; Smith, S.J. Global and regional potential for bioenergy from agricultural and forestry residue biomass. Mitig. Adapt. Strateg. Glob. Chang. 2010, 15, 241–262. https://doi.org/10.1007/s11027-010-9215-4.
14.
Gomez, L.D.; Steele-King, C.G.; McQueen-Mason, S.J. Sustainable liquid biofuels from biomass: The writing’s on the walls. New Phytol. 2008, 178, 473–485. https://doi.org/10.1111/j.1469-8137.2008.02422.x.
15.
Tarabet, L.; Loubar, K.; Lounici, M.S.; et al. Eucalyptus biodiesel as an alternative to diesel fuel: Preparation and tests on DI diesel engine. BioMed Res. Int. 2012, 2012, 1–8. https://doi.org/10.1155/2012/235485.
16.
Shurpali, N.J.; Rannik, Ü.; Jokinen, S.; et al. Neglecting diurnal variations leads to uncertainties in terrestrial nitrous oxide emissions. Sci. Rep. 2016, 6, 25739. https://doi.org/10.1038/srep25739.
17.
Brosse, N.; Dufour, A.; Meng, X.; et al. Miscanthus: A fast-growing crop for biofuels and chemicals production. Biofuels Bioprod. Biorefining 2012, 6, 580–598.
18.
Karp, A.; Hanley, S.J.; Trybush, S.O.; et al. Genetic Improvement of Willow for Bioenergy and Biofuels Free Access. J. Integr. Plant Biol. 2011, 53, 151–165. https://doi.org/10.1111/j.1744-7909.2010.01015.x.
19.
Cybulska, I.; Chaturvedi, T.; Brudecki, G.P.; et al. Chemical characterization and hydrothermal pretreatment of Salicornia bigelovii straw for enhanced enzymatic hydrolysis and bioethanol potential. Bioresour. Technol. 2014, 153, 165–172. https://doi.org/10.1016/j.biortech.2013.11.071.
20.
Chhetri, A.B.; Tango, M.S.; Budge, S.M.; et al. Non-edible plant oils as new sources for biodiesel production. Int. J. Mol. Sci. 2008, 9, 169–180. https://doi.org/10.3390/ijms9020169.
21.
Achinas, S.; Euverink, G.J.W. Consolidated briefing of biochemical ethanol production from lignocellulosic biomass. Electron. J. Biotechnol. 2016, 23, 44–53. https://doi.org/10.1016/j.ejbt.2016.07.006.
22.
Xu, C.; Arancon, R.; Labidi, J.; et al. Lignin depolymerisation strategies: Towards valuable chemicals and fuels. Chem. Soc. Rev. 2014, 43, 7485–7500. https://doi.org/10.1039/c4cs00235k.
23.
Isikgor, F.; Becer, C. Lignocellulosic biomass: A sustainable platform for the production of bio-based chemicals and polymers. Polym. Chem. 2015, 6, 4497–4559. https://doi.org/10.1039/c5py00263j.
24.
Menon, V.; Rao, M. Trends in bioconversion of lignocellulose: Biofuels, platform chemicals & biorefinery concept. Prog. Energy Combust. Sci. 2012, 38, 522–550. https://doi.org/10.1016/j.pecs.2012.02.002.
25.
Sharma, A.; Pareek, V.; Zhang, D. Biomass pyrolysis—A review of modelling, process parameters and catalytic studies. Renew. Sustain. Energy Rev. 2015, 50, 1081–1096. https://doi.org/10.1016/j.rser.2015.04.193.
26.
Zhou, N.; Thilakarathna, W.P.D.W.; He, Q.S.; et al. A review: Depolymerization of lignin to generate high-value bio-products: Opportunities, challenges, and prospects. Front. Energy Res. 2022, 9, 758744. https://doi.org/10.3389/fenrg.2021.758744.
27.
Howard, R.L.; Abotsi, E.; Jansen, V.R.E.L.; et al. Lignocellulose biotechnology: Issues of bioconversion and enzyme production. Afr. J. Biotechnol. 2003, 2, 602–619. https://doi.org/10.5897/ajb2003.000-1115.
28.
Kumar, A.; Kumar, J.; Bhaskar, T. Utilization of lignin: A sustainable and eco-friendly approach. J. Energy Inst. 2020, 93, 235–271. https://doi.org/10.1016/j.joei.2019.03.005.
29.
Chaffey, N.; Alberts, B.; Johnson, A.; et al. Molecular biology of the cell. 4th edn. Ann. Bot. 2003, 91, 401. https://doi.org/10.1093/aob/mcg023.
30.
Roy, R.; Rahman, M.S.; Raynie, D.E. Recent advances of greener pretreatment technologies of lignocellulose. Curr. Res. Green Sustain. Chem. 2020, 3, 100035. https://doi.org/10.1016/j.crgsc.2020.100035.
31.
Bian, J.; Peng, F.; Peng, X.P.; et al. Acetic acid enhanced purification of crude cellulose from sugarcane bagasse: Structural and morphological characterization. BioResources 2012, 7, 4626–4639. https://doi.org/10.15376/biores.7.4.4626-4639.
32.
Kalia, S.; Dufresne, A.; Cherian, B.M.; et al. Cellulose-Based Bio- and Nanocomposites: A Review. Int. J. Polym. Sci. 2011, 2011, 1–35. https://doi.org/10.1155/2011/837875.
33.
Laureano-Perez, L.; Teymouri, F.; Alizadeh, H.; et al. Understanding factors that limit enzymatic hydrolysis of biomass: Characterization of pretreated corn stover. Appl. Biochem. Biotechnol. 2005, 124, 1081–1100. https://doi.org/10.1385/abab:124:1-3:1081.
34.
Zoghlami, A.; Paës, G. Lignocellulosic biomass: Understanding recalcitrance and predicting hydrolysis. Front. Chem. 2019, 7, 874. https://doi.org/10.3389/fchem.2019.00874.
35.
Ou, L.; Dou, C.; Yu, J.H.; et al. Techno-economic analysis of sugar production from lignocellulosic biomass with utilization of hemicellulose and lignin for high-value co-products. Biofuels Bioprod. Biorefining 2021, 15, 404–415. https://doi.org/10.1002/bbb.2170.
36.
Kumar, R.; Singh, S.; Singh, O.V. Bioconversion of lignocellulosic biomass: Biochemical and molecular perspectives. J. Ind. Microbiol. Biotechnol. 2008, 35, 377–391. https://doi.org/10.1007/s10295-008-0327-8.
37.
Gray, M.C.; Converse, A.O.; Wyman, C.E. Sugar monomer and oligomer solubility: Data and predictions for application to biomass hydrolysis. Appl. Biochem. Biotechnol. 2003, 105, 179–194. https://doi.org/10.1385/abab:105:1-3:179.
38.
Yáñez-S, M.; Matsuhiro, B.; Nuñez, C.; et al. Physicochemical characterization of ethanol organosolv lignin (EOL) from Eucalyptus globulus: Effect of extraction conditions on the molecular structure. Polym. Degrad. Stab. 2014, 110, 184–194. https://doi.org/10.1016/j.polymdegradstab.2014.08.026.
39.
Kaiser, K.; Benner, R. Characterization of lignin by gas chromatography and mass spectrometry using a simplified CuO oxidation method. Anal. Chem. 2012, 84, 459–464. https://doi.org/10.1021/ac202004r.
40.
Roy, R.; Rahman, M.S.; Amit, T.A.; et al. Recent advances in lignin depolymerization techniques: A comparative overview of traditional and greener approaches. Biomass 2022, 2, 130–154. https://doi.org/10.3390/biomass2030009.
41.
Brandt, A.; Gräsvik, J.; Hallett, J.P.; et al. Deconstruction of lignocellulosic biomass with ionic liquids. Green Chem. 2013, 15, 550. https://doi.org/10.1039/c2gc36364j.
42.
Hosseini Koupaie, E.; Dahadha, S.; Bazyar Lakeh, A.A.; et al. Enzymatic pretreatment of lignocellulosic biomass for enhanced biomethane production-A review. J. Environ. Manag. 2019, 233, 774–784. https://doi.org/10.1016/j.jenvman.2018.09.106.
43.
Vanholme, R.; Demedts, B.; Morreel, K.; et al. Lignin biosynthesis and structure. Plant Physiol. 2010, 153, 895–905. https://doi.org/10.1104/pp.110.155119.
44.
Li, C.; Zhao, X.; Wang, A.; et al. Catalytic transformation of lignin for the production of chemicals and fuels. Chem. Rev. 2015, 115, 11559–11624. https://doi.org/10.1021/acs.chemrev.5b00155.
45.
Sen, S.; Patil, S.; Argyropoulos, D.S. Thermal properties of lignin in copolymers, blends, and composites: A review. Green Chem. 2015, 17, 4862–4887. https://doi.org/10.1039/c5gc01066g.
46.
Huang, D.; Li, R.; Xu, P.; et al. The cornerstone of realizing lignin value-addition: Exploiting the native structure and properties of lignin by extraction methods. Chem. Eng. J. 2020, 402, 126237. https://doi.org/10.1016/j.cej.2020.126237.
47.
Fernández-Rodríguez, J.; Erdocia, X.; Sánchez, C.; et al. Lignin depolymerization for phenolic monomers production by sustainable processes. J. Energy Chem. 2017, 26, 622–631. https://doi.org/10.1016/j.jechem.2017.02.007.
48.
Tejado, A.; Peña, C.; Labidi, J.; et al. Physico-chemical characterization of lignins from different sources for use in phenol–formaldehyde resin synthesis. Bioresour. Technol. 2007, 98, 1655–1663. https://doi.org/10.1016/j.biortech.2006.05.042.
49.
Li, M.; Pu, Y.; Ragauskas, A.J. Current understanding of the correlation of lignin structure with biomass recalcitrance. Front. Chem. 2016, 4, 45. https://doi.org/10.3389/fchem.2016.00045.
50.
Chakar, F.S.; Ragauskas, A.J. Review of current and future softwood kraft lignin process chemistry. Ind. Crops Prod. 2004, 20, 131–141. https://doi.org/10.1016/j.indcrop.2004.04.016.
51.
Demirbaş, A. Relationships between lignin contents and fixed carbon contents of biomass samples. Energy Convers. Manag. 2003, 44, 1481–1486. https://doi.org/10.1016/s0196-8904(02)00168-1.
52.
Adapa, P.; Tabil, L.; Schoenau, G. Compaction characteristics of barley, canola, oat and wheat straw. Biosyst. Eng. 2009, 104, 335–344. https://doi.org/10.1016/j.biosystemseng.2009.06.022.
53.
Huang, F.; Singh, P.M.; Ragauskas, A.J. Characterization of milled wood lignin (MWL) in loblolly pine stem wood, residue, and bark. J. Agric. Food Chem. 2011, 59, 12910–12916. https://doi.org/10.1021/jf202701b.
54.
Das, A.; Mondal, C. Comparative Kinetic Study of Anaerobic Treatment of Thermally Pretreated Source-Sorted Organic Market Refuse. J. Eng. 2015, 2015, 1–14. https://doi.org/10.1155/2015/684749.
55.
Amin, F.R.; Khalid, H.; Zhang, H.; et al. Pretreatment methods of lignocellulosic biomass for anaerobic digestion. AMB Express 2017, 7, 72. https://doi.org/10.1186/s13568-017-0375-4.
56.
Raud, M.; Tutt, M.; Olt, J.; et al. Dependence of the hydrolysis efficiency on the lignin content in lignocellulosic material. Int. J. Hydrogen Energy 2016, 41, 16338–16343. https://doi.org/10.1016/j.ijhydene.2016.03.190.
57.
Mahmood, N.; Yuan, Z.; Schmidt, J.; et al. Depolymerization of lignins and their applications for the preparation of polyols and rigid polyurethane foams: A review. Renew. Sustain. Energy Rev. 2016, 60, 317–329. https://doi.org/10.1016/j.rser.2016.01.037.
58.
Chio, C.; Sain, M.; Qin, W. Lignin utilization: A review of lignin depolymerization from various aspects. Renew. Sustain. Energy Rev. 2019, 107, 232–249. https://doi.org/10.1016/j.rser.2019.03.008.
59.
Cateto, C.A.; Barreiro, M.F.; Rodrigues, A.E. Monitoring of lignin-based polyurethane synthesis by FTIR-ATR. Ind. Crops Prod. 2008, 27, 168–174. https://doi.org/10.1016/j.indcrop.2007.07.018.
60.
Lora, J.H.; Glasser, W.G. Recent industrial applications of lignin: A sustainable alternative to nonrenewable materials. J. Polym. Environ. 2002, 10, 39–48. https://doi.org/10.1023/a:1021070006895.
61.
Nieminen, K.; Paananen, M.; Sixta, H. Kinetic model for carbohydrate degradation and dissolution during kraft pulping. Ind. Eng. Chem. Res. 2014, 53, 11292–11302. https://doi.org/10.1021/ie501359p.
62.
Zhu, W.; Westman, G.; Theliander, H. Investigation and characterization of lignin precipitation in the lignoboost process. J. Wood Chem. Technol. 2014, 34, 77–97. https://doi.org/10.1080/02773813.2013.838267.
63.
Tomani, P.E. The lignoboost process. Cellul. Chem. Technol. 2010, 44, 53–58.
64.
Argyropoulos, D.D.S.; Crestini, C.; Dahlstrand, C.; et al. Kraft lignin: A valuable, sustainable resource, opportunities and challenges. ChemSusChem 2023, 16, e202300492. https://doi.org/10.1002/cssc.202300492.
65.
Kouisni, L.; Gagné, A.; Maki, K.; et al. LignoForce system for the recovery of lignin from black liquor: Feedstock options, odor profile, and product characterization. ACS Sustain. Chem. Eng. 2016, 4, 5152–5159. https://doi.org/10.1021/acssuschemeng.6b00907.
66.
Gierer, J. Chemical aspects of kraft pulping. Wood Sci. Technol. 1980, 14, 241–266. https://doi.org/10.1007/bf00383453.
67.
Gellerstedt, G. Softwood kraft lignin: Raw material for the future. Ind. Crops Prod. 2015, 77, 845–854. https://doi.org/10.1016/j.indcrop.2015.09.040.
68.
Crestini, C.; Lange, H.; Sette, M.; et al. On the structure of softwood kraft lignin. Green Chem. 2017, 19, 4104–4121. https://doi.org/10.1039/c7gc01812f.
69.
Wang, C.; Kelley, S.S.; Venditti, R.A. Lignin-based thermoplastic materials. ChemSusChem 2016, 9, 770–783. https://doi.org/10.1002/cssc.201501531.
70.
Kun, D.; Pukánszky, B. Polymer/lignin blends: Interactions, properties, applications. Eur. Polym. J. 2017, 93, 618–641. https://doi.org/10.1016/j.eurpolymj.2017.04.035.
71.
Doherty, W.O.S.; Mousavioun, P.; Fellows, C.M. Value-adding to cellulosic ethanol: Lignin polymers. Ind. Crops Prod. 2011, 33, 259–276. https://doi.org/10.1016/j.indcrop.2010.10.022.
72.
Xing, Q.; Ruch, D.; Dubois, P.; et al. Biodegradable and High-Performance Poly(butylene adipate-co-terephthalate)–Lignin UV-Blocking Films. ACS Sustain. Chem. Eng. 2017, 5, 10342–10351. https://doi.org/10.1021/acssuschemeng.7b02370.
73.
Alexy, P.; Košı́ková, B.; Podstránska, G. The effect of blending lignin with polyethylene and polypropylene on physical properties. Polymer 2000, 41, 4901–4908. https://doi.org/10.1016/s0032-3861(99)00714-4.
74.
Wang, Q.; Du, H.; Zhang, F.; et al. Flexible cellulose nanopaper with high wet tensile strength, high toughness and tunable ultraviolet blocking ability fabricated from tobacco stalk via a sustainable method. J. Mater. Chem. A 2018, 6, 13021–13030. https://doi.org/10.1039/c8ta01986j.
75.
Llevot, A.; Grau, E.; Carlotti, S.; et al. From lignin-derived aromatic compounds to novel biobased polymers. Macromol. Rapid Commun. 2016, 37, 9–28. https://doi.org/10.1002/marc.201500474.
76.
Laurichesse, S.; Avérous, L. Chemical modification of lignins: Towards biobased polymers. Prog. Polym. Sci. 2014, 39, 1266–1290. https://doi.org/10.1016/j.progpolymsci.2013.11.004.
77.
Zinovyev, G.; Sumerskii, I.; Korntner, P.; et al. Molar mass-dependent profiles of functional groups and carbohydrates in kraft lignin. J. Wood Chem. Technol. 2017, 37, 171–183. https://doi.org/10.1080/02773813.2016.1253103.
78.
Ragauskas, A.J.; Beckham, G.T.; Biddy, M.J.; et al. Lignin valorization: Improving lignin processing in the biorefinery. Science 2014, 344, 1246843. https://doi.org/10.1126/science.1246843.
79.
Ma, R.; Xu, Y.; Zhang, X. Catalytic oxidation of biorefinery lignin to value-added chemicals to support sustainable biofuel production. ChemSusChem 2015, 8, 24–51.
80.
Kylili, A.; Koutinas, M.; Georgali, P.; et al. Lignin valorisation: Life cycle assessment (LCA) considerations for enabling circular bioeconomy. Int. J. Sustain. Energy 2023, 42, 1008–1027. https://doi.org/10.1080/14786451.2023.2250869.
81.
Strassberger, Z.; Tanase, S.; Rothenberg, G. The pros and cons of lignin valorisation in an integrated biorefinery. RSC Adv. 2014, 4, 25310–25318. https://doi.org/10.1039/c4ra04747h.
82.
Rinaldi, R.; Jastrzebski, R.; Clough, M.T.; et al. Paving the way for lignin valorisation: Recent advances in bioengineering, biorefining and catalysis. Angew. Chem. Int. Ed. 2016, 55, 8164–8215. https://doi.org/10.1002/anie.201510351.
83.
Bilal, M.; Qamar, S.A.; Qamar, M.; et al. Bioprospecting lignin biomass into environmentally friendly polymers—Applied perspective to reconcile sustainable circular bioeconomy. Biomass Convers. Biorefinery 2024, 14, 4457–4483. https://doi.org/10.1007/s13399-022-02600-3.
84.
Culbertson, C.; Treasure, T.; Venditti, R.; et al. Life Cycle Assessment of lignin extraction in a softwood kraft pulp mill. Nord. Pulp Pap. Res. J. 2016, 31, 30–40. https://doi.org/10.3183/npprj-2016-31-01-p030-040.
85.
Marson, A.; Samec, J.S.M.; Manzardo, A. Consequential life cycle assessment of kraft lignin recovery with chemical recycling. Sci. Total Environ. 2023, 882, 163660. https://doi.org/10.1016/j.scitotenv.2023.163660.
86.
Tokede, O.O.; Whittaker, A.; Mankaa, R.; et al. Life cycle assessment of asphalt variants in infrastructures: The case of lignin in Australian road pavements. Structures 2020, 25, 190–199. https://doi.org/10.1016/j.istruc.2020.02.026.
87.
Bernier, E.; Lavigne, C.; Robidoux, P.Y. Life cycle assessment of kraft lignin for polymer applications. Int. J. Life Cycle Assess. 2013, 18, 520–528. https://doi.org/10.1007/s11367-012-0503-y.
88.
Hermansson, F.; Janssen, M.; Svanström, M. Allocation in life cycle assessment of lignin. Int. J. Life Cycle Assess. 2020, 25, 1620–1632. https://doi.org/10.1007/s11367-020-01770-4.
89.
Yuan, T.Q.; Xu, F.; Sun, R.C. Role of lignin in a biorefinery: Separation characterization and valorization. J. Chem. Technol. Biotechnol. 2013, 88, 346–352. https://doi.org/10.1002/jctb.3996.
90.
Torres, L.A.Z.; Woiciechowski, A.L.; Tanobe, V.O.D.A.; et al. Lignin as a potential source of high-added value compounds: A review. J. Clean. Prod. 2020, 263, 121499. https://doi.org/10.1016/j.jclepro.2020.121499.
91.
Dessbesell, L.; Paleologou, M.; Leitch, M.; et al. Global lignin supply overview and kraft lignin potential as an alternative for petroleum-based polymers. Renew. Sustain. Energy Rev. 2020, 123, 109768. https://doi.org/10.1016/j.rser.2020.109768.
92.
Chung, H.; Washburn, N.R. Chemistry of lignin-based materials. Green Mater. 2013, 1, 137–160. https://doi.org/10.1680/gmat.12.00009.
93.
Gosselink, R.J.A.; Abächerli, A.; Semke, H.; et al. Analytical protocols for characterisation of sulphur-free lignin. Ind. Crops Prod. 2004, 19, 271–281. https://doi.org/10.1016/j.indcrop.2003.10.008.
94.
Azadi, P.; Inderwildi, O.; Farnood, R.; et al. Liquid fuels, hydrogen and chemicals from lignin: A critical review. Renew. Sustain. Energy Rev. 2013, 21, 506–523. https://doi.org/10.1016/j.rser.2012.12.022.
95.
Espinoza-Acosta, J.L.; Torres-Chávez, P.I.; Carvajal-Millán, E.; et al. Ionic liquids and organic solvents for recovering lignin from lignocellulosic biomass. BioResources 2014, 9, 3660. https://doi.org/10.15376/biores.9.2.3660-3687.
96.
Jablonský, M.; Kočiš, J.; Ház, A.; et al. The approach the isolation of lignins and its characterization. In Proceedings of the 5th International Scientific Conference Renewable Energy Sources, Tatranské Matliare, Slovak Republic, 20–22 May 2014.
97.
Zhang, M.; Xu, Y.; Li, K. Removal of residual lignin of ethanol-based organosolv pulp by an alkali extraction process. J. Appl. Polym. Sci. 2007, 106, 630–636. https://doi.org/10.1002/app.26622.
98.
Gomes, F.J.B.; Souza, R.E.D.; Brito, E.O.; et al. A review on lignin sources and uses. J. Appl. Biotechnol. Bioeng. 2020, 7, 100–105. https://doi.org/10.15406/jabb.2020.07.00222.
99.
Constant, S.; Basset, C.; Dumas, C.; et al. Reactive organosolv lignin extraction from wheat straw: Influence of Lewis acid catalysts on structural and chemical properties of lignins. Ind. Crops Prod. 2015, 65, 180–189. https://doi.org/10.1016/j.indcrop.2014.12.009.
100.
Li, M.F.; Sun, S.N.; Xu, F.; et al. Sequential solvent fractionation of heterogeneous bamboo organosolv lignin for value-added application. Sep. Purif. Technol. 2012, 101, 18–25. https://doi.org/10.1016/j.seppur.2012.09.013.
101.
Pan, X.; Arato, C.; Gilkes, N.; et al. Biorefining of softwoods using ethanol organosolv pulping: Preliminary evaluation of process streams for manufacture of fuel-grade ethanol and co-products. Biotechnol. Bioeng. 2005, 90, 473–481. https://doi.org/10.1002/bit.20453.
102.
Lange, H.; Decina, S.; Crestini, C. Oxidative upgrade of lignin—Recent routes reviewed. Eur. Polym. J. 2013, 49, 1151–1173. https://doi.org/10.1016/j.eurpolymj.2013.03.002.
103.
Vázquez, G.; Antorrena, G.; González, J.; et al. The influence of pulping conditions on the structure of acetosolv eucalyptus lignins. J. Wood Chem. Technol. 1997, 17, 147–162. https://doi.org/10.1080/02773819708003124.
104.
Rabelo, S.C.; Nakasu, P.Y.S.; Scopel, E.; et al. Organosolv pretreatment for biorefineries: Current status, perspectives, and challenges. Bioresour. Technol. 2023, 369, 128331. https://doi.org/10.1016/j.biortech.2022.128331.
105.
Lee, S.H.; Lee, S.B. The Hildebrand solubility parameters, cohesive energy densities and internal energies of 1-alkyl-3-methylimidazolium-based room temperature ionic liquids. Chem. Commun. 2005, 41, 3469–3471. https://doi.org/10.1039/b503740a.
106.
Zhu, S.; Wu, Y.; Chen, Q.; et al. Dissolution of cellulose with ionic liquids and its application: A mini-review. Green Chem. 2006, 8, 325. https://doi.org/10.1039/b601395c.
107.
Tan, S.; MacFarlane, D.; Upfal, J.; et al. Extraction of lignin from lignocellulose at atmospheric pressure using alkylbenzenesulfonate ionic liquid. Green Chem. 2009, 11, 339–345.
108.
Kamiya, N.; Matsushita, Y.; Hanaki, M.; et al. Enzymatic in situ saccharification of cellulose in aqueous-ionic liquid media. Biotechnol. Lett. 2008, 30, 1037–1040. https://doi.org/10.1007/s10529-008-9638-0.
109.
Cequier, E.; Aguilera, J.; Balcells, M.; et al. Extraction and characterization of lignin from olive pomace: A comparison study among ionic liquid, sulfuric acid, and alkaline treatments. Biomass Convers. Biorefinery 2019, 9, 241–252. https://doi.org/10.1007/s13399-019-00400-w.
110.
Brandt-Talbot, A.; Gschwend, F.J.V.; Fennell, P.S.; et al. An economically viable ionic liquid for the fractionation of lignocellulosic biomass. Green Chem. 2017, 19, 3078–3102. https://doi.org/10.1039/c7gc00705a.
111.
Liang, X.; Fu, Y.; Chang, J. Recovery of ionic liquid via a hybrid methodology of electrodialysis with ultrafiltration after biomass pretreatment. Bioresour. Technol. 2016, 220, 289–296. https://doi.org/10.1016/j.biortech.2016.08.092.
112.
Weerachanchai, P.; Lee, J.M. Recovery of lignin and ionic liquid by using organic solvents. J. Ind. Eng. Chem. 2017, 49, 122–132. https://doi.org/10.1016/j.jiec.2017.01.018.
113.
Yu, H.; Hu, J.; Fan, J.; et al. One-pot conversion of sugars and lignin in ionic liquid and recycling of ionic liquid. Ind. Eng. Chem. Res. 2012, 51, 3452–3457. https://doi.org/10.1021/ie2025807.
114.
Marcus, Y. The variety of deep eutectic solvents. In Deep Eutectic Solvents; Springer: Cham, Switzerland, 2019; pp. 13–44. https://doi.org/10.1007/978-3-030-00608-2_2.
115.
Chen, Y.; Zhang, L.; Yu, J.; et al. High-purity lignin isolated from poplar wood meal through dissolving treatment with deep eutectic solvents. R. Soc. Open Sci. 2019, 6, 181757. https://doi.org/10.1098/rsos.181757.
116.
Ijardar, S.P.; Singh, V.; Gardas, R.L. Revisiting the physicochemical properties and applications of deep eutectic solvents. Molecules 2022, 27, 1368. https://doi.org/10.3390/molecules27041368.
117.
Smith, E.L.; Abbott, A.P.; Ryder, K.S. Deep Eutectic Solvents (DESs) and Their Applications. Chem. Rev. 2014, 114, 11060–11082. https://doi.org/10.1021/cr300162p.
118.
Satlewal, A.; Agrawal, R.; Bhagia, S.; et al. Natural deep eutectic solvents for lignocellulosic biomass pretreatment: Recent developments, challenges and novel opportunities. Biotechnol. Adv. 2018, 36, 2032–2050. https://doi.org/10.1016/j.biotechadv.2018.08.009.
119.
Alvarez-Vasco, C.; Ma, R.; Quintero, M.; et al. Unique low-molecular-weight lignin with high purity extracted from wood by deep eutectic solvents (DES): A source of lignin for valorization. Green Chem. 2016, 18, 5133–5141. https://doi.org/10.1039/c6gc01007e.
120.
Francisco, M.; van den Bruinhorst, A.; Kroon, M.C. New natural and renewable low transition temperature mixtures (LTTMs): Screening as solvents for lignocellulosic biomass processing. Green Chem. 2012, 14, 2153–2157. https://doi.org/10.1039/c2gc35660k.
121.
Yiin, C.L.; Yusup, S.; Quitain, A.T.; et al. Physicochemical properties of low transition temperature mixtures in water. Chem. Eng. Trans. 2015, 45, 1525–1530. https://doi.org/10.3303/cet1545255.
122.
Evstigneyev, E.I.; Yuzikhin, O.S.; Gurinov, A.A.; et al. Study of Structure of Industrial Acid Hydrolysis Lignin, Oxidized in the H₂O₂-H₂SO₄ System. J. Wood Chem. Technol. 2016, 36, 259–269. https://doi.org/10.1080/02773813.2015.1137945.
123.
Vishtal, A.; Kraslawski, A. Challenges in industrial applications of technical lignins. BioResources 2011, 6, 3547–3568. https://doi.org/10.15376/biores.6.3.3547-3568.
124.
Zhang, J.; Deng, H.; Lin, L.; et al. Isolation and characterization of wheat straw lignin with a formic acid process. Bioresour. Technol. 2010, 101, 2311–2316. https://doi.org/10.1016/j.biortech.2009.11.037.
125.
Chandra, R.; Bura, R.; Mabee, W.; et al. Substrate pretreatment: The key to effective enzymatic hydrolysis of lignocellulosics? In Advances in Biochemical Engineering/Biotechnology; Springer: Berlin/Heidelberg, Germany, 2007; pp. 67–93. https://doi.org/10.1007/10_2007_064.
126.
Nakagame, S.; Chandra, R.P.; Kadla, J.F.; et al. The isolation, characterization and effect of lignin isolated from steam pretreated Douglas-fir on the enzymatic hydrolysis of cellulose. Bioresour. Technol. 2011, 102, 4507–4517. https://doi.org/10.1016/j.biortech.2010.12.082.
127.
Sazanov, Y.N.; Kulikova, E.M.; Fedorova, G.N.; et al. Potential activity of hydrolytic lignin in copolymerization reactions. Russ. J. Appl. Chem. 2009, 82, 1592–1599. https://doi.org/10.1134/s107042720909016x.
128.
Carrott, P.; Carrott, M. Lignin—From natural adsorbent to activated carbon: A review. Bioresour. Technol. 2007, 98, 2301–2312. https://doi.org/10.1016/j.biortech.2006.08.008.
129.
Wen, J.L.; Sun, S.L.; Xue, B.L.; et al. Recent Advances in Characterization of Lignin Polymer by Solution-State Nuclear Magnetic Resonance (NMR) Methodology. Materials 2013, 6, 359–391. https://doi.org/10.3390/ma6010359.
130.
Naegele, H.; Pfitzer, J.; Ziegler, L.; et al. In Lignin in Polymer Composites; William Andrew Publishing; Norwich, NY, USA, 2016.
131.
Wang, H.; Pu, Y.; Ragauskas, A.; et al. From lignin to valuable products–strategies, challenges, and prospects. Bioresour. Technol. 2019, 271, 449–461. https://doi.org/10.1016/j.biortech.2018.09.072.
132.
Ramezani, N.; Sain, M. Thermal and physiochemical characterization of lignin extracted from wheat straw by organosolv process. J. Polym. Environ. 2018, 26, 3109–3116. https://doi.org/10.1007/s10924-018-1199-2.
133.
Salm, O.S.; Kudrjashova, M.; Kulp, M. Green non-destructive approach for quantifying hydroxyl groups in lignin using ATR-FTIR spectroscopy and chemometric methods. Vib. Spectrosc. 2026, 143, 103897. https://doi.org/10.1016/j.vibspec.2026.103897.
134.
Zirbes, M.; Graßl, T.; Neuber, R.; et al. Peroxodicarbonat als grünes Oxidationsmittel für den selektiven Abbau von Kraft-Lignin zu Vanillin. Angew. Chem. 2023, 135, e202219217. https://doi.org/10.1002/ange.202219217.
135.
Lindenbeck, L.; Dahlhaus, S.; Wende, L.; et al. Breaking down lignin in gamma-valerolactone: Advances into a bioelectrorefinery. Green Chem. Lett. Rev. 2024, 17, 2390867. https://doi.org/10.1080/17518253.2024.2390867.
136.
Liu, Y.; Lindenbeck, L.M.; Frauscher, M.; et al. Nickel-Driven Electrochemical Upgrading of Kraft Lignin to Value-Added Aliphatic and Phenolic Products. Molecules 2025, 30, 2544. https://doi.org/10.3390/molecules30122544.
137.
Han, Y.; Simmons, B.A.; Singh, S. Perspective on oligomeric products from lignin depolymerization: Their generation, identification, and further valorization. Ind. Chem. Mater. 2023, 1, 207–223. https://doi.org/10.1039/d2im00059h.
138.
Duan, D.; Ruan, R.; Lei, H.; et al. Microwave-assisted co-pyrolysis of pretreated lignin and soapstock for upgrading liquid oil: Effect of pretreatment parameters on pyrolysis behavior. Bioresour. Technol. 2018, 258, 98–104. https://doi.org/10.1016/j.biortech.2018.02.119.
139.
Zhou, C.; Jiang, W.; Via, B.; et al. Prediction of mixed hardwood lignin and carbohydrate content using ATR-FTIR and FT-NIR. Carbohydr. Polym. 2015, 121, 336–341. https://doi.org/10.1016/j.carbpol.2014.11.062.
140.
Nowak, P.M. What does it mean that “something is green”? The fundamentals of a Unified Greenness Theory. Green Chem. 2023, 25, 4625–4640. https://doi.org/10.1039/d3gc00800b.
141.
Wang, W.; Wang, Y.; Qi, Y.; et al. Interfacial Electronic Modulation Redirects Anodic Radical Chemistry for Selective C─C Bond Cleavage in Electro-Oxidative Lignin Depolymerization. Angew. Chem. Int. Ed. 2026, 65, e1876863. https://doi.org/10.1002/anie.1876863.
142.
Zakzeski, J.; Bruijnincx, P.C.A.; Weckhuysen, B.M. In situ spectroscopic investigation of the cobalt-catalyzed oxidation of lignin model compounds in ionic liquids. Green Chem. 2011, 13, 671–680. https://doi.org/10.1039/c0gc00437e.
143.
Lindenbeck, L.M.; Brand, S.; Schatz, F.; et al. One-pot electrocatalytic lignin depolymerization with in situ extraction: A feasible approach for the production of biomass-based oils. Green Chem. 2025, 27, 9927–9936.
144.
Duan, D.; Zhao, Y.; Fan, L.; et al. Low-Power Microwave Radiation-assisted Depolymerization of Ethanol Organosolv Lignin in Ethanol/Formic Acid Mixtures. BioResources 2017, 12, 5308. https://doi.org/10.15376/biores.12.3.5308-5320.
145.
El Mansouri, N.E.; Yuan, Q.; Huang, F. Synthesis and characterization of kraft lignin-based epoxy resins. BioResources 2011, 6, 2492–2503. https://doi.org/10.15376/biores.6.3.2492-2503.
146.
Nunes, K.S.D.; Pardini, L.C. Purification and characterization methods for lignin biomass as a potential precursor for carbon materials. Cellul. Chem. Technol. 2019, 53, 227–242. https://doi.org/10.35812/cellulosechemtechnol.2019.53.23.
147.
Yang, C.; Qin, J.; Sun, S.; et al. Progress in developing methods for lignin depolymerization and elucidating the associated mechanisms. Eur. Polym. J. 2024, 210, 112995. https://doi.org/10.1016/j.eurpolymj.2024.112995.
148.
Wei, N.; Qi, S.; Wang, G.; et al. Acid-promoted lignin reductive depolymerization under mild conditions via a condensation minimizing approach: From organosolv lignin to woody biomass. Fuel 2023, 338, 127311. https://doi.org/10.1016/j.fuel.2022.127311.
149.
Liu, B.; Liu, L.; Deng, B.; et al. Application and prospect of organic acid pretreatment in lignocellulosic biomass separation: A review. Int. J. Biol. Macromol. 2022, 222, 1400–1413. https://doi.org/10.1016/j.ijbiomac.2022.09.270.
150.
Guan, W.; Tsang, C.W.; Lin, C.S.K.; et al. A review on high catalytic efficiency of solid acid catalysts for lignin valorization. Bioresour. Technol. 2020, 298, 122432. https://doi.org/10.1016/j.biortech.2019.122432.
151.
Zabeti, M.; Baltrusaitis, J.; Seshan, K. Chemical routes to hydrocarbons from pyrolysis of lignocellulose using Cs promoted amorphous silica alumina catalyst. Catal. Today 2016, 269, 156–165. https://doi.org/10.1016/j.cattod.2015.11.024.
152.
Zou, Q.; Lin, W.; Xu, D.; et al. Study the effect of zeolite pore size and acidity on the catalytic pyrolysis of Kraft lignin. Fuel Process. Technol. 2022, 237, 107467. https://doi.org/10.1016/j.fuproc.2022.107467.
153.
Kurnia, I.; Karnjanakom, S.; Bayu, A.; et al. In-situ catalytic upgrading of bio-oil derived from fast pyrolysis of lignin over high aluminum zeolites. Fuel Process. Technol. 2017, 167, 730–737. https://doi.org/10.1016/j.fuproc.2017.08.026.
154.
Kong, L.; Liu, C.; Gao, J.; et al. Efficient and controllable alcoholysis of Kraft lignin catalyzed by porous zeolite-supported nickel-copper catalyst. Bioresour. Technol. 2019, 276, 310–317. https://doi.org/10.1016/j.biortech.2019.01.015.
155.
Yu, X.; Wei, Z.; Lu, Z.; et al. Activation of lignin by selective oxidation: An emerging strategy for boosting lignin depolymerization to aromatics. Bioresour. Technol. 2019, 291, 121885. https://doi.org/10.1016/j.biortech.2019.121885.
156.
Yuan, Z.; Cheng, S.; Leitch, M.; et al. Hydrolytic degradation of alkaline lignin in hot-compressed water and ethanol. Bioresour. Technol. 2010, 101, 9308–9313. https://doi.org/10.1016/j.biortech.2010.06.140.
157.
Adhikari, S.; Srinivasan, V.; Fasina, O. Catalytic pyrolysis of raw and thermally treated lignin using different acidic zeolites. Energy Fuels 2014, 28, 4532–4538. https://doi.org/10.1021/ef500902x.
158.
Shu, R.; Xu, Y.; Ma, L.; et al. Controllable production of guaiacols and phenols from lignin depolymerization using Pd/C catalyst cooperated with metal chloride. Chem. Eng. J. 2018, 338, 457–464. https://doi.org/10.1016/j.cej.2018.01.002.
159.
Galkin, M.V.; Samec, J.S.M. Selective route to 2-propenyl aryls directly from wood by a tandem organosolv and palladium-catalysed transfer hydrogenolysis. ChemSusChem 2014, 7, 2154–2158. https://doi.org/10.1002/cssc.201402017.
160.
Shao, Y.; Xia, Q.; Dong, L.; et al. Selective production of arenes via direct lignin upgrading over a niobium-based catalyst. Nat. Commun. 2017, 8, 16104. https://doi.org/10.1038/ncomms16104.
161.
Wanmolee, W.; Laosiripojana, N.; Daorattanachai, P.; et al. Catalytic conversion of organosolv lignins to phenolic monomers in different organic solvents and effect of operating conditions on yield with methyl isobutyl ketone. ACS Sustain. Chem. Eng. 2018, 6, 3010–3018. https://doi.org/10.1021/acssuschemeng.7b02721.
162.
Güvenatam, B.; Heeres, E.H.J.; Pidko, E.A.; et al. Lewis acid-catalyzed depolymerization of soda lignin in supercritical ethanol/water mixtures. Catal. Today 2016, 269, 9–20. https://doi.org/10.1016/j.cattod.2015.08.039.
163.
Fearon, O.; Kuitunen, S.; Vuorinen, T. Reaction kinetics of strong nucleophiles with a dimeric non-phenolic lignin model compound with α-carbonyl functionality (adleron) in aqueous alkali solution. Holzforschung 2016, 70, 811–818. https://doi.org/10.1515/hf-2015-0236.
164.
Hidajat, M.J.; Riaz, A.; Park, J.; et al. Depolymerization of concentrated sulfuric acid hydrolysis lignin to high-yield aromatic monomers in basic sub- and supercritical fluids. Chem. Eng. J. 2017, 317, 9–19. https://doi.org/10.1016/j.cej.2017.02.045.
165.
Poletto, M. (Ed.) In Lignin—Trends and Applications; BoD–Books on Demand: Hamburg, Germany, 2018. https://doi.org/10.5772/intechopen.68464.
166.
Long, J.; Zhang, Q.; Wang, T.; et al. An efficient and economical process for lignin depolymerization in biomass-derived solvent tetrahydrofuran. Bioresour. Technol. 2014, 154, 10–17. https://doi.org/10.1016/j.biortech.2013.12.020.
167.
Mensah, M.; Tia, R.; Adei, E.; et al. A DFT mechanistic study on base-catalyzed cleavage of the β-O-4 ether linkage in lignin: Implications for selective lignin depolymerization. Front. Chem. 2022, 10, 793759. https://doi.org/10.3389/fchem.2022.793759.
168.
Lin, X.; Chen, L.; Li, H.; et al. Mild depolymerization of the sinocalamus oldhami alkali lignin to phenolic monomer with base and activated carbon supported nickel-tungsten carbide catalyst composite system. Bioresour. Technol. 2021, 333, 125136. https://doi.org/10.1016/j.biortech.2021.125136.
169.
Rößiger, B.; Röver, R.; Unkelbach, G.; et al. Production of Bio-Phenols for Industrial Application: Scale-Up of the Base-Catalyzed Depolymerization of Lignin. Green Sustain. Chem. 2017, 7, 193–202. https://doi.org/10.4236/gsc.2017.73015.
170.
Long, J.; Xu, Y.; Wang, T.; et al. Efficient base-catalyzed decomposition and in situ hydrogenolysis process for lignin depolymerization and char elimination. Appl. Energy 2015, 141, 70–79. https://doi.org/10.1016/j.apenergy.2014.12.025.
171.
Lancefield, C.S.; Panovic, I.; Deuss, P.J.; et al. Pre-treatment of lignocellulosic feedstocks using biorenewable alcohols: Towards complete biomass valorisation. Green Chem. 2017, 19, 202–214. https://doi.org/10.1039/c6gc02739c.
172.
Seo, E.J.; Cho, Y.T.; Park, J.H. Status and Applicability of Lignin Depolymerization Technology. J. Korean Soc. Environ. Eng. 2025, 47, 23–49. https://doi.org/10.4491/ksee.2025.47.1.23.
173.
Chaudhary, R.; Dhepe, P.L. Solid base catalyzed depolymerization of lignin into low molecular weight products. Green Chem. 2017, 19, 778–788. https://doi.org/10.1039/c6gc02701f.
174.
Dabral, S.; Engel, J.; Mottweiler, J.; et al. Mechanistic studies of base-catalysed lignin depolymerisation in dimethyl carbonate. Green Chem. 2018, 20, 170–182. https://doi.org/10.1039/c7gc03110f.
175.
Mahmood, N.; Yuan, Z.; Schmidt, J.; et al. Production of polyols via direct hydrolysis of kraft lignin: Effect of process parameters. Bioresour. Technol. 2013, 139, 13–20. https://doi.org/10.1016/j.biortech.2013.03.199.
176.
Erdocia, X.; Prado, R.; Corcuera, M.Á.; et al. Base catalyzed depolymerization of lignin: Influence of organosolv lignin nature. Biomass Bioenergy 2014, 66, 379–386. https://doi.org/10.1016/j.biombioe.2014.03.021.
177.
Agarwal, A.; Rana, M.; Park, J.H. Advancement in technologies for the depolymerization of lignin. Fuel Process. Technol. 2018, 181, 115–132. https://doi.org/10.1016/j.fuproc.2018.09.017.
178.
Song, Q.; Wang, F.; Xu, J. Hydrogenolysis of lignosulfonate into phenols over heterogeneous nickel catalysts. Chem. Commun. 2012, 48, 7019. https://doi.org/10.1039/c2cc31414b.
179.
Song, Q.; Wang, F.; Cai, J.; et al. Lignin depolymerization (LDP) in alcohol over nickel-based catalysts via a fragmentation–hydrogenolysis process. Energy Environ. Sci. 2013, 6, 994. https://doi.org/10.1039/c2ee23741e.
180.
Zhang, J.; Teo, J.; Chen, X.; et al. A Series of NiM (M = Ru, Rh, and Pd) Bimetallic Catalysts for Effective Lignin Hydrogenolysis in Water. Acs Catal. 2014, 4, 1574–1583. https://doi.org/10.1021/cs401199f.
181.
Zhang, J.; Cai, Y.; Lu, G.; et al. Facile and selective hydrogenolysis of β-O-4 linkages in lignin catalyzed by Pd–Ni bimetallic nanoparticles supported on ZrO₂. Green Chem. 2016, 18, 6229–6235. https://doi.org/10.1039/c6gc02265k.
182.
Zhai, Y.; Li, C.; Xu, G.; et al. Depolymerization of lignin via a non-precious Ni–Fe alloy catalyst supported on activated carbon. Green Chem. 2017, 19, 1895–1903. https://doi.org/10.1039/c7gc00149e.
183.
Tang, D.; Huang, X.; Tang, W.; et al. Lignin-to-chemicals: Application of catalytic hydrogenolysis of lignin to produce phenols and terephthalic acid via metal-based catalysts. Int. J. Biol. Macromol. 2021, 190, 72–85. https://doi.org/10.1016/j.ijbiomac.2021.08.188.
184.
Xu, W.; Miller, S.J.; Agrawal, P.K.; et al. Depolymerization and hydrodeoxygenation of switchgrass lignin with formic acid. ChemSusChem 2012, 5, 667–675. https://doi.org/10.1002/cssc.201100695.
185.
Van den Bosch, S.; Schutyser, W.; Vanholme, R.; et al. Reductive lignocellulose fractionation into soluble lignin-derived phenolic monomers and dimers and processable carbohydrate pulps. Energy Environ. Sci. 2015, 8, 1748–1763. https://doi.org/10.1039/c5ee00204d.
186.
Ouyang, X.; Huang, X.; Zhu, J.; et al. Catalytic Conversion of Lignin in Woody Biomass into Phenolic Monomers in Methanol/Water Mixtures without External Hydrogen. ACS Sustain. Chem. Eng. 2019, 7, 13764–13773. https://doi.org/10.1021/acssuschemeng.9b01497.
187.
Cheng, C.; Li, P.; Yu, W.; et al. Nonprecious metal/bimetallic catalytic hydrogenolysis of lignin in a mixed-solvent system. ACS Sustain. Chem. Eng. 2020, 8, 16217–16228. https://doi.org/10.1021/acssuschemeng.0c05362.
188.
Barta, K.; Warner, G.R.; Beach, E.S.; et al. Depolymerization of organosolv lignin to aromatic compounds over Cu-doped porous metal oxides. Green Chem. 2014, 16, 191–196. https://doi.org/10.1039/c3gc41184b.
189.
Konnerth, H.; Zhang, J.; Ma, D.; et al. Base promoted hydrogenolysis of lignin model compounds and organosolv lignin over metal catalysts in water. Chem. Eng. Sci. 2015, 123, 155–163. https://doi.org/10.1016/j.ces.2014.10.045.
190.
Zhu, G.; Ouyang, X.; Yang, Y.; et al. Selective cleavage of aryl ether bonds in dimeric lignin model compounds. RSC Adv. 2016, 6, 17880–17887. https://doi.org/10.1039/c5ra26235f.
191.
Zhang, J. Catalytic transfer hydrogenolysis as an efficient route in cleavage of lignin and model compounds. Green Energy Environ. 2018, 3, 328–334. https://doi.org/10.1016/j.gee.2018.08.001.
192.
Cheng, C.; Shen, D.; Gu, S.; et al. State-of-the-art catalytic hydrogenolysis of lignin for the production of aromatic chemicals. Catal. Sci. Technol. 2018, 8, 6275–6296. https://doi.org/10.1039/c8cy00845k.
193.
Ye, K.; Liu, Y.; Wu, S.; et al. A review for lignin valorization: Challenges and perspectives in catalytic hydrogenolysis. Ind. Crops Prod. 2021, 172, 114008. https://doi.org/10.1016/j.indcrop.2021.114008.
194.
Chen, B.; Li, F.; Yuan, G. Highly stable and recyclable graphene layers protected nickel–cobalt bimetallic nanoparticles as tunable hydrotreating catalysts for phenylpropane linkages in lignin. Catal. Lett. 2017, 147, 2877–2885. https://doi.org/10.1007/s10562-017-2179-1.
195.
Park, J.; Oh, S.; Kim, J.Y.; et al. Comparison of degradation features of lignin to phenols over Pt catalysts prepared with various forms of carbon supports. RSC Adv. 2016, 6, 16917–16924. https://doi.org/10.1039/c5ra21875f.
196.
Huang, Y.; Duan, Y.; Qiu, S.; et al. Lignin-first biorefinery: A reusable catalyst for lignin depolymerization and application of lignin oil to jet fuel aromatics and polyurethane feedstock. Sustain. Energy Fuels 2018, 2, 637–647. https://doi.org/10.1039/c7se00535k.
197.
Nolte, M.W.; Zhang, J.; Shanks, B.H. Ex situ hydrodeoxygenation in biomass pyrolysis using molybdenum oxide and low pressure hydrogen. Green Chem. 2016, 18, 134–138. https://doi.org/10.1039/c5gc01614b.
198.
Ma, R.; Hao, W.; Ma, X.; et al. Catalytic ethanolysis of Kraft lignin into high-value small-molecular chemicals over a nanostructured α-molybdenum carbide catalyst. Angew. Chem. 2014, 126, 7438–7443. https://doi.org/10.1002/ange.201402752.
199.
Sergeev, A.; Webb, J.; Hartwig, J. A heterogeneous nickel catalyst for the hydrogenolysis of aryl ethers without arene hydrogenation. J. Am. Chem. Soc. 2012, 134, 20226–20229. https://doi.org/10.1021/ja3085912.
200.
Sun, J.; Karim, A.M.; Zhang, H.; et al. Carbon-supported bimetallic Pd–Fe catalysts for vapor-phase hydrodeoxygenation of guaiacol. J. Catal. 2013, 306, 47–57. https://doi.org/10.1016/j.jcat.2013.05.020.
201.
Parsell, T.H.; Owen, B.C.; Klein, I.; et al. Cleavage and hydrodeoxygenation (HDO) of C-O bonds relevant to lignin conversion using Pd/Zn synergistic catalysis. Chem. Sci. 2013, 4, 806–813. https://doi.org/10.1039/c2sc21657d.
202.
Chen, M.; Li, Y.; Liu, H.; et al. Lignin hydrogenolysis: Tuning the reaction by lignin chemistry. Int. J. Biol. Macromol. 2024, 279, 135169. https://doi.org/10.1016/j.ijbiomac.2024.135169.
203.
Nguyen, L.T.; Phan, D.P.; Sarwar, A.; et al. Valorization of industrial lignin to value-added chemicals by chemical depolymerization and biological conversion. Ind. Crops Prod. 2021, 161, 113219. https://doi.org/10.1016/j.indcrop.2020.113219.
204.
Zhang, J.; Asakura, H.; Rijn, J.V.; et al. Highly efficient, NiAu-catalyzed hydrogenolysis of lignin into phenolic chemicals. Green Chem. 2014, 16, 2432–2437. https://doi.org/10.1039/c3gc42589d.
205.
He, J.; Zhao, C.; Lercher, J.A. Ni-catalyzed cleavage of aryl ethers in the aqueous phase. J. Am. Chem. Soc. 2012, 134, 20768–20775. https://doi.org/10.1021/ja309915e.
206.
Song, Q.; Cai, J.; Zhang, J.; et al. Hydrogenation and cleavage of the C-O bonds in the lignin model compound phenethyl phenyl ether over a nickel-based catalyst. Chin. J. Catal. 2013, 34, 651–658. https://doi.org/10.1016/s1872-2067(12)60535-x.
207.
Cooreman, E.; Vangeel, T.; Van Aelst, K.; et al. Perspective on overcoming scale-up hurdles for the reductive catalytic fractionation of lignocellulose biomass. Ind. Eng. Chem. Res. 2020, 59, 17035–17045. https://doi.org/10.1021/acs.iecr.0c02294.
208.
Ouyang, X.; Huang, X.; Hendriks, B.M.S.; et al. Coupling organosolv fractionation and reductive depolymerization of woody biomass in a two-step catalytic process. Green Chem. 2018, 20, 2308–2319. https://doi.org/10.1039/c8gc00639c.
209.
Torr, K.M.; van de Pas, D.J.; Cazeils, E.; et al. Mild hydrogenolysis of in-situ and isolated Pinus radiata lignins. Bioresour. Technol. 2011, 102, 7608–7611. https://doi.org/10.1016/j.biortech.2011.05.040.
210.
McVeigh, A.; Bouxin, F.P.; Jarvis, M.C.; et al. Catalytic depolymerisation of isolated lignin to fine chemicals: Part 2—Process optimisation. Catal. Sci. Technol. 2016, 6, 4142–4150. https://doi.org/10.1039/c5cy01896j.
211.
Kim, K.H.; Simmons, B.A.; Singh, S. Catalytic transfer hydrogenolysis of ionic liquid processed biorefinery lignin to phenolic compounds. Green Chem. 2017, 19, 215–224. https://doi.org/10.1039/c6gc02473d.
212.
Musolino, M.; Scarpino, L.; Mauriello, F.; et al. Selective transfer hydrogenolysis of glycerol promoted by palladium catalysts in absence of hydrogen. Green Chem. 2009, 11, 1511. https://doi.org/10.1039/b915745j.
213.
Toledano, A.; Serrano, L.; Labidi, J.; et al. Heterogeneously catalysed mild hydrogenolytic depolymerisation of lignin under microwave irradiation with hydrogen-donating solvents. ChemCatChem 2013, 5, 977–985. https://doi.org/10.1002/cctc.201200616.
214.
Anderson, E.M.; Stone, M.L.; Katahira, R.; et al. Flowthrough reductive catalytic fractionation of biomass. Joule 2017, 1, 613–622. https://doi.org/10.1016/j.joule.2017.10.004.
215.
Zhou, L.; Zhu, Z.; Luo, B.; et al. Bimetallic NiCo catalyzed enzymatic hydrolysis lignin hydrogenolysis to produce aromatic monomers. Fuel 2023, 333, 126357. https://doi.org/10.1016/j.fuel.2022.126357.
216.
Li, H.; Huang, Y.; Lin, X.; et al. Microwave-assisted depolymerization of lignin with synergic alkali catalysts and a transition metal catalyst in the aqueous system. React. Chem. Eng. 2022, 7, 1750–1761. https://doi.org/10.1039/d2re00091a.
217.
Dhar, P.; Vinu, R. Understanding lignin depolymerization to phenols via microwave-assisted solvolysis process. J. Environ. Chem. Eng. 2017, 5, 4759–4768. https://doi.org/10.1016/j.jece.2017.08.031.
218.
Jiang, L.; Guo, H.; Li, C.; et al. Selective cleavage of lignin and lignin model compounds without external hydrogen, catalyzed by heterogeneous nickel catalysts. Chem. Sci. 2019, 10, 4458–4468. https://doi.org/10.1039/c9sc00691e.
219.
Zhou, M.; Sharma, B.K.; Liu, P.; et al. Microwave Assisted Depolymerization of Alkaline Lignin over Hydrotalcite-Based CuNiAl Mixed Oxides. ACS Sustain. Chem. Eng. 2018, 6, 11519–11528. https://doi.org/10.1021/acssuschemeng.8b01697.
220.
Shao, L.; Wang, C.; Liu, Y.; et al. Efficient depolymerization of lignin through microwave-assisted Ru/C catalyst cooperated with metal chloride in methanol/formic acid media. Front. Bioeng. Biotechnol. 2022, 10, 1082341. https://doi.org/10.3389/fbioe.2022.1082341.
221.
Zhu, G.; Qiu, X.; Zhao, Y.; et al. Depolymerization of lignin by microwave-assisted methylation of benzylic alcohols. Bioresour. Technol. 2016, 218, 718–722. https://doi.org/10.1016/j.biortech.2016.07.021.
222.
Liu, X.; Bouxin, F.P.; Fan, J.; et al. Microwave-assisted catalytic depolymerization of lignin from birch sawdust to produce phenolic monomers utilizing a hydrogen-free strategy. J. Hazard. Mater. 2021, 402, 123490. https://doi.org/10.1016/j.jhazmat.2020.123490.
223.
Zhu, G.; Jin, D.; Zhao, L.; et al. Microwave-assisted selective cleavage of Cα–Cβ bond for lignin depolymerization. Fuel Process. Technol. 2017, 161, 155–161. https://doi.org/10.1016/j.fuproc.2017.03.020.
224.
Duan, D.; Wang, Y.; Ruan, R.; et al. Comparative study on various alcohols solvolysis of organosolv lignin using microwave energy: Physicochemical and morphological properties. Chem. Eng. Process.-Process Intensif. 2018, 126, 38–44. https://doi.org/10.1016/j.cep.2017.10.023.
225.
Zhou, N.; Yang, J.; Lu, X.; et al. Microwave-assisted depolymerization of lignin and a biphasic extraction method for the recovery of bio-oil and phenolic monomers. J. Anal. Appl. Pyrolysis 2022, 161, 105403. https://doi.org/10.1016/j.jaap.2021.105403.
226.
Polidoro, D.; Selva, M.; Luque, R. Microwave-assisted catalytic transfer hydrogenolysis of lignin-derived aromatic ethers over Ru/C. Mol. Catal. 2023, 542, 113082. https://doi.org/10.1016/j.mcat.2023.113082.
227.
Santana, J.A.; Carvalho, W.S.; Ataíde, C.H. Catalytic effect of ZSM-5 zeolite and HY-340 niobic acid on the pyrolysis of industrial kraft lignins. Ind. Crops Prod. 2018, 111, 126–132. https://doi.org/10.1016/j.indcrop.2017.10.023.
228.
Gosz, K.; Kosmela, P.; Hejna, A.; et al. Biopolyols obtained via microwave-assisted liquefaction of lignin: Structure, rheological, physical and thermal properties. Wood Sci. Technol. 2018, 52, 599–617. https://doi.org/10.1007/s00226-018-0991-4.
229.
Shao, L.; Zhang, Q.; You, T.; et al. Microwave-assisted efficient depolymerization of alkaline lignin in methanol/formic acid media. Bioresour. Technol. 2018, 264, 238–243. https://doi.org/10.1016/j.biortech.2018.05.083.
230.
da Cruz, M.G.A.; Rodrigues, B.V.M.; Ristic, A.; et al. On the product selectivity in the electrochemical reductive cleavage of 2-phenoxyacetophenone, a lignin model compound. Green Chem. Lett. Rev. 2022, 15, 153–161. https://doi.org/10.1080/17518253.2022.2025462.
231.
Wang, Y.; Sun, S.; Li, F.; et al. Production of vanillin from lignin: The relationship between β-O-4 linkages and vanillin yield. Ind. Crops Prod. 2018, 116, 116–121. https://doi.org/10.1016/j.indcrop.2018.02.043.
232.
Luo, J.; Liu, T.L. Electrochemical valorization of lignin: Status, challenges, and prospects. J. Bioresour. Bioprod. 2023, 8, 1–14. https://doi.org/10.1016/j.jobab.2022.11.003.
233.
Bilal, M.; Menezes, P.W.; Thomas, A.; et al. Electrocatalytic valorization of lignin. RSC Sustain. 2026, 4, 2042–2077. https://doi.org/10.1039/d5su00803d.
234.
Zhu, H.; Wang, L.; Chen, Y.; et al. Electrochemical depolymerization of lignin into renewable aromatic compounds in a non-diaphragm electrolytic cell. RSC Adv. 2014, 4, 29917. https://doi.org/10.1039/c4ra03793f.
235.
Yang, C.; Maldonado, S.; Stephenson, C.R.J. Electrocatalytic lignin oxidation. ACS Catal. 2021, 11, 10104–10114. https://doi.org/10.1021/acscatal.1c01767.
236.
Guschakowski, M.; Schröder, U. Direct and indirect Electrooxidation of glycerol to value-added products. ChemSusChem 2021, 14, 5216–5225. https://doi.org/10.1002/cssc.202100556.
237.
Ayub, R.; Raheel, A. High-value chemicals from electrocatalytic depolymerization of lignin: Challenges and opportunities. Int. J. Mol. Sci. 2022, 23, 3767. https://doi.org/10.3390/ijms23073767.
238.
Jiang, H.; Xue, A.; Wang, Z.; et al. Electrochemical degradation of lignin by ROS. Sustain. Chem. 2020, 1, 345–360. https://doi.org/10.3390/suschem1030023.
239.
Putra, F.J.N.; Aliyah, A.; Kahar, P.; et al. Electrochemical Strategies for Lignin Valorization: Advancing Biomass Utilization. Molecules 2026, 31, 2109. https://doi.org/10.3390/molecules31122109.
240.
Li, S.; Davis, K.; Leem, G. Electrocatalytic and photocatalytic approaches to lignin conversion. In Lignin Utilization Strategies: From Processing to Applications; American Chemical Society: Washington, DC, USA, 2021; pp. 97–121. https://doi.org/10.1021/bk-2021-1377.ch005.
241.
Xie, B.; Tobimatsu, Y.; Kamitakahara, H.; et al. Reaction selectivity in electro-oxidation of lignin dimer model compounds and synthetic lignin with different mediators for the laccase mediator system (PZH, NHPI, ABTS). ACS Sustain. Chem. Eng. 2022, 10, 6633–6641. https://doi.org/10.1021/acssuschemeng.2c00432.
242.
Wu, Z.; Zhang, X.; Fan, H.; et al. Allyl halide induced electrochemical degradation of lignin into double-bonded phenolic monomers. Int. J. Biol. Macromol. 2023, 242, 124947. https://doi.org/10.1016/j.ijbiomac.2023.124947.
243.
Tolba, R.; Tian, M.; Wen, J.; et al. Electrochemical oxidation of lignin at IrO₂-based oxide electrodes. J. Electroanal. Chem. 2010, 649, 9–15. https://doi.org/10.1016/j.jelechem.2009.12.013.
244.
He, Y.; Li, R.; Hu, M.; et al. Selective oxidative cleavage of lignin through tailored reactive oxygen species. Tetrahedron Green Chem. 2025, 7, 100090. https://doi.org/10.1016/j.tgchem.2025.100090.
245.
Di Fidio, N.; Timmermans, J.W.; Antonetti, C.; et al. Electro-oxidative depolymerisation of technical lignin in water using platinum, nickel oxide hydroxide and graphite electrodes. New J. Chem. 2021, 45, 9647–9657. https://doi.org/10.1039/d1nj01037a.
246.
Zirbes, M.; Schmitt, D.; Beiser, N.; et al. Anodic degradation of lignin at active transition metal-based alloys and performance-enhanced anodes. ChemElectroChem 2019, 6, 155–161. https://doi.org/10.1002/celc.201801218.
247.
Ouyang, D.; Gao, D.; Qiang, Y.; et al. Highly-efficient conversion of lignin to electricity by nickel foam anode loaded with solid electrocatalysts. Appl. Catal. B Environ. 2023, 328, 122491. https://doi.org/10.1016/j.apcatb.2023.122491.
248.
Wang, R.; Sun, D.; Zheng, C.; et al. Oxidative Depolymerization of Lignin to Aromatic Monomers Catalyzed by MgFe₂O₄ Under Alkaline Conditions. ChemistrySelect 2026, 11, e05099. https://doi.org/10.1002/slct.202505099.
249.
Zhu, H.; Chen, Y.; Qin, T.; et al. Lignin depolymerization via an integrated approach of anode oxidation and electro-generated H₂O₂ oxidation. Rsc Adv. 2014, 4, 6232. https://doi.org/10.1039/c3ra47516f.
250.
Brix, A.C.; Krysiak, O.A.; Cechanaviciutè, I.A.; et al. Oxidative depolymerisation of Kraft lignin: From fabrication of multi-metal-modified electrodes for vanillin electrogeneration via pulse electrolysis to high-throughput screening of multi-metal composites. ChemElectroChem 2024, 11, e202300483. https://doi.org/10.1002/celc.202300483.
251.
Wang, J.; Li, Y.; Hummel, C.; et al. Electrocatalytic Production of a Liquid Organic Hydrogen Carrier with Anodic Valorization of the Process: Review and Outlook. Energy Fuels 2025, 39, 132–165. https://doi.org/10.1021/acs.energyfuels.4c04644.
252.
Biswas, B.; Sakhakarmy, M.; Rahman, T.; et al. Selective production of phenolic monomer via catalytic depolymerization of lignin over cobalt-nickel-zirconium dioxide catalyst. Bioresour. Technol. 2024, 398, 130517. https://doi.org/10.1016/j.biortech.2024.130517.
253.
Stiefel, S.; Schmitz, A.; Peters, J.; et al. An integrated electrochemical process to convert lignin to value-added products under mild conditions. Green Chem. 2016, 18, 4999–5007. https://doi.org/10.1039/c6gc00878j.
254.
Biswas, B.; Kumar, A.; Krishna, B.B.; et al. Catalytic depolymerization of lignin for the selective production of phenolic monomers over cobalt-supported calcium catalysts. Energy Fuels 2023, 37, 3813–3824. https://doi.org/10.1021/acs.energyfuels.2c04193.
255.
Lim, H.W.; Cho, D.K.; Park, J.H.; et al. Rational design of dimensionally stable anodes for active chlorine generation. ACS Catal. 2021, 11, 12423–12432. https://doi.org/10.1021/acscatal.1c03653.
256.
Shao, D.; Liang, J.; Cui, X.; et al. Electrochemical oxidation of lignin by two typical electrodes: Ti/Sb SnO₂ and Ti/PbO₂. Chem. Eng. J. 2014, 244, 288–295. https://doi.org/10.1016/j.cej.2014.01.074.
257.
Teng, J.; Zhang, Y.; Li, P.; et al. Hydroxyl radical in anodic oxidation-based electrochemical advanced oxidation processes: Critical understanding and a new perspective. Sustain. Horizons 2025, 16, 100156. https://doi.org/10.1016/j.horiz.2025.100156.
258.
Alkhadra, M.A.; Su, X.; Suss, M.E.; et al. Electrochemical methods for water purification, ion separations, and energy conversion. Chem. Rev. 2022, 122, 13547–13635. https://doi.org/10.1021/acs.chemrev.1c00396.
259.
Ngokpho, B.; Therdkatanyuphong, P.; Krukkratoke, P.; et al. Controlling electrochemical lignin depolymerization via halide chemistry at boron-doped diamond electrodes. RSC Adv. 2025, 15, 33209–33223. https://doi.org/10.1039/d5ra05524e.
260.
Liu, X.; You, S.; Ma, F.; et al. Characterization of electrode fouling during electrochemical oxidation of phenolic pollutant. Front. Environ. Sci. Eng. 2021, 15, 53. https://doi.org/10.1007/s11783-020-1345-7.
261.
Ferreira, M.; Varela, H.; Torresi, R.M.; et al. Electrode passivation caused by polymerization of different phenolic compounds. Electrochim. Acta 2006, 52, 434–442. https://doi.org/10.1016/j.electacta.2006.05.025.
262.
Xia, Z.; Li, J.; Zhang, J.; et al. Processing and valorization of cellulose, lignin and lignocellulose using ionic liquids. J. Bioresour. Bioprod. 2020, 5, 79–95. https://doi.org/10.1016/j.jobab.2020.04.001.
263.
Di Marino, D.; Stöckmann, D.; Kriescher, S.; et al. Electrochemical depolymerisation of lignin in a deep eutectic solvent. Green Chem. 2016, 18, 6021–6028. https://doi.org/10.1039/c6gc01353h.
264.
Li, P.; Zhou, H.; Tao, Y.; et al. Recent development and perspectives of solvents and electrode materials for electrochemical oxidative degradation of lignin. Electroanalysis 2022, 34, 1529–1539. https://doi.org/10.1002/elan.202200100.
265.
Stiefel, S.; Lölsberg, J.; Kipshagen, L.; et al. Controlled depolymerization of lignin in an electrochemical membrane reactor. Electrochem. Commun. 2015, 61, 49–52. https://doi.org/10.1016/j.elecom.2015.09.028.
266.
Popescu, A.E.P.; Torralba, J.; Bonet, J.; et al. Solvent Screening and Process Simulation for Vanillin Production from Lignin. CET J.-Chem. Eng. Trans. 2020, 81, 835. https://doi.org/10.3303/cet2081140.
267.
Schmitt, D.; Regenbrecht, C.; Hartmer, M.; et al. Highly selective generation of vanillin by anodic degradation of lignin: A combined approach of electrochemistry and product isolation by adsorption. Beilstein J. Org. Chem. 2015, 11, 473–480. https://doi.org/10.3762/bjoc.11.53.
268.
Du, X.; Zhang, H.; Sullivan, K.P.; et al. Electrochemical lignin conversion. ChemSusChem 2020, 13, 4318–4343. https://doi.org/10.1002/cssc.202001187.
269.
García-Rollán, M.; Toscano-de los Riscos, M.; Ruiz-Rosas, R.; et al. Oxidative electrochemical depolymerization of lignin using highly active self-standing electrocatalysts prepared by electrospinning of lignin. Biomass Bioenergy 2025, 193, 107560. https://doi.org/10.1016/j.biombioe.2024.107560.
270.
Geng, S.; González-Cobos, J.; Pérez-Carcelén, L.; et al. Towards the development of smart nickel/carbon-based materials for lignin electrolysis: First steps for unravelling the influence of nickel loading and catalyst morphology on lignin electrooxidation. Appl. Catal. B Environ. Energy 2025, 365, 124947. https://doi.org/10.1016/j.apcatb.2024.124947.
271.
Brachi, M.; El Housseini, W.; Beaver, K.; et al. Advanced electroanalysis for electrosynthesis. ACS Org. Inorg. Au 2024, 4, 141–187. https://doi.org/10.1021/acsorginorgau.3c00051.
272.
Jiang, F.; Dong, Z.; Lou, X.; et al. Selective and mild oxidation of α-hydroxyl groups in lignin by 2-iodoxybenzoic acid. Front. Bioeng. Biotechnol. 2025, 13, 1654739. https://doi.org/10.3389/fbioe.2025.1654739.
273.
Kroll, C.; Borchert, H. Metabolism of the stable nitroxyl radical 4-oxo-2, 2, 6, 6-tetramethylpiperidine-N-oxyl (TEMPONE). Eur. J. Pharm. Sci. 1999, 8, 5–9. https://doi.org/10.1016/s0928-0987(98)00047-5.
274.
Rafiee, M.; Alherech, M.; Karlen, S.D.; et al. Electrochemical aminoxyl-mediated oxidation of primary alcohols in lignin to carboxylic acids: Polymer modification and depolymerization. J. Am. Chem. Soc. 2019, 141, 15266–15276. https://doi.org/10.1021/jacs.9b07243.
275.
Bosque, I.; Magallanes, G.; Rigoulet, M.; et al. Redox catalysis facilitates lignin depolymerization. ACS Cent. Sci. 2017, 3, 621–628. https://doi.org/10.1021/acscentsci.7b00140.
276.
Bhardwaj, M.; Grover, P.; Rasool, B.; et al. Recent Advances in N-Hyrdoxypthalimide: As a Free Radical Initiator and its Applications. Asian J. Org. Chem. 2022, 11, e202200442. https://doi.org/10.1002/ajoc.202200442.
277.
Liu, W.; Cui, Y.; Du, X.; et al. High efficiency hydrogen evolution from native biomass electrolysis. Energy Environ. Sci. 2016, 9, 467–472. https://doi.org/10.1039/c5ee03019f.
278.
Zhang, Z.; Gogoi, P.; Geng, Z.; et al. Low temperature lignin depolymerization to aromatic compounds with a redox couple catalyst. Fuel 2020, 281, 118799. https://doi.org/10.1016/j.fuel.2020.118799.
279.
Wang, L.; Liu, S.; Meng, J.; et al. Electrocatalytic Lignin Valorization via Enhanced H₂O₂ Generation Using a MWNCT-Modified Gas Diffusion Electrode. ChemPlusChem 2025, 90, e202400769. https://doi.org/10.1002/cplu.202400769.
280.
Liu, X.; Wang, Y.; Duan, H. Recent progress in electrocatalytic conversion of lignin: From monomers, dimers, to raw lignin. Precis. Chem. 2024, 2, 428–446. https://doi.org/10.1021/prechem.4c00024.
281.
Hasan, M.; Akbari, A.; Greenlee, L.F. Combined electrocatalytic oxidation and reduction to selectively cleave β-O-4 linkage of lignin over platinum electrode in organic solvent: Secondary treatment opportunity for CELF process. ACS Sustain. Chem. Eng. 2023, 11, 15262–15272. https://doi.org/10.1021/acssuschemeng.3c03191.
282.
Du, Y.; Chen, X.; Shen, W.; et al. Electrocatalysis as an efficient alternative to thermal catalysis over PtRu bimetallic catalysts for hydrogenation of benzoic acid derivatives. Green Chem. 2023, 25, 5489–5500. https://doi.org/10.1039/d3gc01540h.
283.
Lang, M.; Li, H. Toward mild synthesis of functional chemicals from lignin-derived phenolics via emerging catalytic technology. Chem Catal. 2023, 3, 100609. https://doi.org/10.1016/j.checat.2023.100609.
284.
Tian, Y.; Gao, M.; Tang, Z.; et al. In-situ generated hydrogen for selective hydrogenolysis of lignin catalyzed by Mg-Al mixed oxides with nested Ni nanoparticles. J. Catal. 2024, 440, 115833. https://doi.org/10.1016/j.jcat.2024.115833.
285.
Zeng, Y.; Zhao, M.; Zeng, H.; et al. Recent progress in advanced catalysts for electrocatalytic hydrogenation of organics in aqueous conditions. Escience 2023, 3, 100156. https://doi.org/10.1016/j.esci.2023.100156.
286.
Yun, Y.S.; Berdugo-Díaz, C.E.; Flaherty, D.W. Advances in understanding the selective hydrogenolysis of biomass derivatives. ACS Catal. 2021, 11, 11193–11232. https://doi.org/10.1021/acscatal.1c02866.
287.
Garedew, M.; Young-Farhat, D.; Bhatia, S.; et al. Electrocatalytic cleavage of lignin model dimers using ruthenium supported on activated carbon cloth. Sustain. Energy Fuels 2020, 4, 1340–1350. https://doi.org/10.1039/c9se00912d.
288.
Lam, J.C.H.; Lowe, C.B.; Li, Z.; et al. Electrocatalytic upgrading of model lignin monomers with earth abundant metal electrodes. Green Chem. 2014, 17, 601–609. https://doi.org/10.1039/c4gc01632g.
289.
Tan, S.L.; Liu, G.B.; Gao, X.; et al. Raney Ni–Al alloy-mediated reduction of alkylated phenols in water. J. Chem. Res. 2009, 2009, 5–7. https://doi.org/10.3184/030823409x393637.
290.
Mahdavi, B.; Lafrance, A.; Martel, A.; et al. Electrocatalytic hydrogenolysis of lignin model dimers at Raney nickel electrodes. J. Appl. Electrochem. 1997, 27, 605–611. https://doi.org/10.1023/a:1018463131891.
291.
Cyr, A.; Chiltz, F.; Jeanson, P.; et al. Electrocatalytic hydrogenation of lignin models at Raney nickel and palladium-based electrodes. Can. J. Chem. 2000, 78, 307–315. https://doi.org/10.1139/cjc-78-3-307.
292.
Luo, H.; Weeda, E.P.; Alherech, M.; et al. Oxidative catalytic fractionation of lignocellulosic biomass under non-alkaline conditions. J. Am. Chem. Soc. 2021, 143, 15462–15470. https://doi.org/10.1021/jacs.1c08635.
293.
Liu, M.; Wen, Y.; Qi, J.; et al. Fine Chemicals Prepared by Bamboo Lignin Degradation through Electrocatalytic Redox between Cu Cathode and Pb/PbO₂ Anode in Alkali Solution. ChemistrySelect 2017, 2, 4956–4962. https://doi.org/10.1002/slct.201700881.
294.
Wu, W.B.; Huang, J.M. Electrochemical cleavage of aryl ethers promoted by sodium borohydride. J. Org. Chem. 2014, 79, 10189–10195. https://doi.org/10.1021/jo5018537.
295.
Sbei, N.; Hardwick, T.; Ahmed, N. Green chemistry: Electrochemical organic transformations via paired electrolysis. ACS Sustain. Chem. Eng. 2021, 9, 6148–6169. https://doi.org/10.1021/acssuschemeng.1c00665.
296.
Liu, F.; Gao, X.; Guo, Z.; et al. Sustainable adipic acid production via paired electrolysis of lignin-derived phenolic compounds with water as hydrogen and oxygen sources. J. Am. Chem. Soc. 2024, 146, 15275–15285. https://doi.org/10.1021/jacs.4c02835.
297.
Ali, A.; Jönsson, L.J.; Ji, X.; et al. Electrochemical coupling of lignin-derived phenolic valorization and green hydrogen production: A minireview. Mater. Adv. 2026, 7, 2563–2578. https://doi.org/10.1039/d5ma01203a.
298.
Chang, C.; Gupta, P. Exploring the oxidative effects of the microbial electro-Fenton process on the depolymerization of lignin extracted from rice straw in a bio-electrochemical system coupled with wastewater treatment. Biomacromolecules 2023, 24, 1220–1232. https://doi.org/10.1021/acs.biomac.2c01281.
299.
Amouzegar, K.; Savadogo, O. Electrocatalytic hydrogenation of phenol on highly dispersed Pt electrodes. Electrochim. Acta 1994, 39, 557–559. https://doi.org/10.1016/0013-4686(94)80101-0.
300.
Li, Z.; Garedew, M.; Lam, C.H.; et al. Mild electrocatalytic hydrogenation and hydrodeoxygenation of bio-oil derived phenolic compounds using ruthenium supported on activated carbon cloth. Green Chem. 2012, 14, 2540. https://doi.org/10.1039/c2gc35552c.
301.
Zhou, P.; Guo, S.X.; Li, L.; et al. Selective Electrochemical Hydrogenation of Phenol with Earth-abundant Ni−MoO₂ Heterostructured Catalysts: Effect of Oxygen Vacancy on Product Selectivity. Angew. Chem. 2023, 135, e202214881. https://doi.org/10.1002/ange.202214881.
302.
Wijaya, Y.; Grossmann-Neuhaeusler, T.; Dhewangga Putra, R.; et al. Electrocatalytic hydrogenation of guaiacol in diverse electrolytes using a stirred slurry reactor. ChemSusChem 2020, 13, 629–639.

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