Conversion of Organosolv and Kraft lignins into value-added compounds assisted by an acidic deep eutectic solvent

Sosa, Filipe H. B.; Bjelić, Ana; Coutinho, João A. P.; Costa, Mariana C.; Likozar, Blaž; Grojzdek, Edita Jasiukaitytė; Grilc, Miha; Lopes, André M. da Costa

doi:10.1039/d2se00859a

Cited by 13 publications

(4 citation statements)

References 71 publications

(142 reference statements)

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“…18b) to get the final product. The catalytic conversion of kraft lignin and organosolv was also carried out by Sosa et al 163 using acidic DESs made of ChCl : OA at 80 °C. Further addition of H 2 SO 4 and H 2 O 2 as a co-catalyst to the DESs system improves the lignin depolymerization from kraft and organosolv lignin by up to 26.1% and 27.8%, respectively.…”

Section: Usedmentioning

confidence: 99%

Recent advances in catalytic conversion of lignin to value-added chemicals using ionic liquids and deep eutectic solvents: a critical review

Singh,

Mehra,

Kumar

2024

Green Chem.

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Section: Usedmentioning

confidence: 99%

Recent advances in catalytic conversion of lignin to value-added chemicals using ionic liquids and deep eutectic solvents: a critical review

Singh,

Mehra,

Kumar

2024

Green Chem.

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“…Besides, in previous reports, acidic DESs had been applied in lignin conversion. For example, Lopes et al reported that dissolution of lignin in acidic DES favored the formation of lignin oligomers, which could be further convert into syringol, acetosyringone, vanillic and syringic acids 48 . Yuan et al described that phenolic diketones could be obtained from lignin oil after acidic DES dissolution 49 .…”

Section: Characterization Of the Regenerated Lignin From The Des Solu...mentioning

confidence: 99%

Biomass-Based Acidic Deep Eutectic Solvents for Efficient Dissolution of Lignin: Towards Performance and Mechanism Elucidation

Huang¹,

Chen²,

Zhao³

et al. 2023

Acta Physico Chimica Sinica

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Lignocellulose utilization has the unique feature of net-zero carbon emissions. Thus, the utilization of lignocellulose as a renewable alternative to fossil-based carbon resources is one of the most promising strategies to achieve "carbon neutrality". Lignin has been recognized as the most abundant aromatic biopolymer on Earth; hence, it could be the most promising alternative to fossil-based aromatics. The efficient dissolution of lignin is crucial for lignin upgrading, which relies on the design of innovative and robust solvents. Herein, we designed several biomass-derived acidic deep eutectic solvents (DESs) using choline chloride, betaine, and L-carnitine as hydrogen bond acceptors (HBAs), and four protic compounds as hydrogen bond donors (HBDs), namely, oxalic acid, benzoic acid, ethyl gallate, and 5-methoxysalicylic acid. The designed DESs can dissolve different types of lignin, including alkali lignin (AL), dealkaline lignin (DAL), enzymatic hydrolysis lignin (EHL), and Kraft lignin (KL). Lignin dissolution was found to be affected by the relative contents of three phenylpropanoid monomers in lignin: syringyl (S), guaiacyl (G), and p-hydroxyphenyl (H) units. More S and fewer H units in lignin could result in higher solubility. G-, S-, and H-type structural units were found in EHL, while AL, KL, and DAL had only G-type structural units. Therefore, EHL could be more easily dissolved than AL, KL, and DAL in the most developed DESs. The hydroxyl group content of the four lignin samples had a significant impact on lignin dissolution. AL (1.98 mmol•g −1 ) and EHL (1.93 mmol•g −1 ) had much higher contents of phenolic hydroxyl groups than DAL (0.62 mmol•g −1 ), implying that AL and EHL had higher polarity than DAL. This resulted in different dissolution behaviors in different DESs with varying polarities. However, the sulfonate groups afforded KL with much higher polarity, thus resulting in the special dissolution behavior of KL. It is to be noted that not all cases of dissolving lignin in the developed DESs conformed to the above rules. Therefore, it is necessary to further explore the effect of the properties of the DESs on the dissolution of different lignins. Choline chloride was the preferred HBA to construct DESs with good performance and adaptability to lignin dissolution, whereas suitable acidity enabled benzoic acid and ethyl gallate to be favorable HBDs. Systematic investigation revealed that an efficient DES for lignin dissolution should possess stronger hydrogen-bonding acidity (α > 0.95) and appropriate polarity matching with the dissolved lignin. In addition, the pKa value of the HBD and the acidity of the DESs were also efficient indices for estimating the performance of an acidic DES in dissolving lignin, and the pKa value and acidity could be well correlated with the polarity. Generally, HBDs (e.g., BA and EG in this study) with moderate pKa values can be employed to construct robust DESs to dissolve lignin with satisfactory solubility. Additionally, the viscosity of the DESs should have an impac...

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“…Lignin properties, mainly ionizable functional groups and molecular weights, were studied for their effects on the LNP formation. Three types of lignin (i.e., kraft lignin (KL), organosolv lignin (OL), and ethanol soluble lignin (EKL)), which are commonly reported as starting materials for value-added lignin application, 44 were studied covering a reasonable range of ionizable functional group contents and molecular weight distributions. As summarized in Table 1, KL had 14% and 41% higher phenolic groups than OL and EKL, respectively.…”

Section: Effects Of Lignin Properties On the Lnp Formationmentioning

confidence: 99%

Size-tailorable lignin nanoparticle synthesis: effects of solution chemistry and DLVO forces on amphiphilic balance of lignin

Li,

Zhang,

Lee

et al. 2023

Green Chem.

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Conversion of Organosolv and Kraft lignins into value-added compounds assisted by an acidic deep eutectic solvent

Abstract: In this study, an acidic deep eutectic solvent (DES) was used as benign solvent to valorise technical lignins by breaking down their structure into value-added aromatic compounds. The action of...

Cited by 13 publications

References 71 publications

Recent advances in catalytic conversion of lignin to value-added chemicals using ionic liquids and deep eutectic solvents: a critical review

Recent advances in catalytic conversion of lignin to value-added chemicals using ionic liquids and deep eutectic solvents: a critical review

Biomass-Based Acidic Deep Eutectic Solvents for Efficient Dissolution of Lignin: Towards Performance and Mechanism Elucidation

Size-tailorable lignin nanoparticle synthesis: effects of solution chemistry and DLVO forces on amphiphilic balance of lignin

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