Thermochemical lignin depolymerization and conversion to aromatics in subcritical methanol: effects of catalytic conditions

Singh, Sunit Kumar; Nandeshwar, Kunal; Ekhe, J. D.

doi:10.1039/c5nj02916c

Cited by 41 publications

(22 citation statements)

References 26 publications

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“…Ekhe and co‐workers performed catalytic depolymerization of Kraft lignin in H 2 O/MeOH co‐solvents without addition of hydrogen and obtained high yields of alkylphenols with minimum char formation . Methanol reforming and condensation mechanism of lignin was proposed in the same group . The combination of Raney Ni and H‐USY outperformed Raney Ni or H‐USY alone for the catalytic hydrogenolysis of lignin due to synergistic catalytic effect .…”

Section: Conventional Approach – Catalytic Depolymerization Of Technimentioning

confidence: 99%

Recent Advances in the Catalytic Depolymerization of Lignin towards Phenolic Chemicals: A Review

et al. 2020

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The efficient valorization of lignin could dictate the success of the 2nd generation biorefinery. Lignin, accounting for on average a third of the lignocellulosic biomass, is the most promising candidate for sustainable production of value‐added phenolics. However, the structural alteration induced during lignin isolation is often depleting its potential for value‐added chemicals. Recently, catalytic reductive depolymerization of lignin has appeared to be a promising and effective method for its valorization to obtain phenolic monomers. The present study systematically summarizes the far‐reaching and state‐of‐the‐art lignin valorization strategies during different stages, including conventional catalytic depolymerization of technical lignin, emerging reductive catalytic fractionation of protolignin, stabilization strategies to inhibit the undesired condensation reactions, and further catalytic upgrading of lignin‐derived monomers. Finally, the potential challenges for the future researches on the efficient valorization of lignin and possible solutions are proposed.

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Section: Conventional Approach – Catalytic Depolymerization Of Technimentioning

confidence: 99%

Recent Advances in the Catalytic Depolymerization of Lignin towards Phenolic Chemicals: A Review

et al. 2020

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“…The main components determined in wild and cultivated doraji are methyl‐furan (10.16, 10.29%), furfural (10.08, 16.17%), 5‐methyl‐furfural (8.49, 10.14%), 2‐furanmethanol (3.29, 2.31%) and 1‐(2‐furanyl)‐ethanone (3.38, 4.06%). The compounds 2‐methoxy‐phenol [1] (3.65%), 2‐methoxy‐4‐(1‐propenyl)‐phenol [2] (0.97%) and 1‐(4‐hydroxy‐3‐methoxyphenyl)‐2‐propanone [3] (2.05%) (Figure ), which might be the products of thermochemical lignin depolymerization (Singh, Nandeshwar, & Ekhe, ), in wild doraji were nearly 3 times higher than those in cultivated doraji with relative percentages of 1.08, 0.34 and 0.64%, respectively. These compounds together with furfural, methyl‐furfural, 1‐hydroxy‐2‐butanone, 2‐furanmethanol, acetate, 2‐hydroxy‐3‐methyl‐2‐cyclopenten‐1‐one, 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone and 2,2‐methylenebis‐furan, were significantly different in their percentages between the two kinds of samples ( P < 0.05).…”

Section: Resultsmentioning

confidence: 99%

Application of a solvent‐free solid injection technique coupled with GC–MS for discrimination between the secondary metabolites of wild and cultivated South Korean medicinal foods

Truong

El‐Aty

Kim

et al. 2017

Biomedical Chromatography

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Solvent-free solid injection was applied to differentiate between wild and cultivated South Korean medicinal foods, including dureup (Aralia elata), deodeok (Codonopsis lanceolata) and doraji (Platycodon grandiflorus). A number of compounds were identified in wild and cultivated dureup (53 and 46), deodeok (47 and 51) and doraji (43 and 38). Secondary metabolites, including butanal,2-methyl-, β-caryophyllene, neoclovene, α-humulene, γ-curcumene, β-bisabolene, and phytol, were identified in dureup with significantly (P < 0.05) different amounts between both types. In deodeok, squalene and other main components such as acetic acid, methyl ester, furan-methyl-furfural, 2-furan-methanol, and 5-methyl-furfural, were statistically different between the two types. Doraji has significantly different compounds such as furfural, 5-methyl-furfural, 2-methoxy-phenol, 2-methoxy-4-(1-propenyl)-phenol, and 1-(4-hydroxy-3-methoxyphenyl)-2-propanone. Although we failed to confirm the key compounds, a new compound, namely desaspidinol, was synthesized for the first time and its retention index determined under the experimental conditions. This solventless, easy technique can be used as a simple way to discriminate between wild and cultivated types of medicinal plants via identification of volatile markers or specific fingerprints.

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“…The intermediate products undergo a condensation reaction, leading to a final product which is rich in solid carbon residues. This phenomenon is not observed in the case of zeolites, due to the presence of acid centers capable of catalyzing the direct methylation of the aromatic ring, which retard or prevent any potential condensation reactions [27].…”

Section: Depolymerization In Supercritical Liquidsmentioning

confidence: 99%

“…It is becoming increasingly common for the depolymerization of lignin to be carried out with the use of supercritical liquids [27][28][29][30]. The thermochemical depolymerization of lignin in supercritical methanol with various catalysts was studied by Singh et al [27]. Zeolites, sodium hydroxide, and iron filings were used in the process.…”

Section: Depolymerization In Supercritical Liquidsmentioning

confidence: 99%

Depolymerization and Activation of Lignin: Current State of Knowledge and Perspectives

Kłapiszewski¹,

Szalaty²,

Jesionowski³

2018

Lignin - Trends and Applications

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A very important topic in present-day research is the depolymerization of lignin, meaning the multi-parametric decomposition of the biopolymer into low-molecular-weight products (monomers) by breaking of the intermolecular bonds. Depolymerization can occur under many different factors, such as high temperature or catalysts, which determine the mechanism of disintegration. In the case of lignin, this process is carried out in order to obtain many valuable low-molecular-weight compounds. It is becoming more and more popular as a result of the use of ionic liquids, but methods using alkaline, acidic, and metallic catalysts, as well as pyrolysis and supercritical fluids, are also known. All of these methods will be described in detail in this chapter.

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Thermochemical lignin depolymerization and conversion to aromatics in subcritical methanol: effects of catalytic conditions

Abstract: Solvolytic depolymerization of lignin was studied under three different catalytic conditions and explained using a schematic representation of the mechanisms.

Cited by 41 publications

References 26 publications

Recent Advances in the Catalytic Depolymerization of Lignin towards Phenolic Chemicals: A Review

Recent Advances in the Catalytic Depolymerization of Lignin towards Phenolic Chemicals: A Review

Application of a solvent‐free solid injection technique coupled with GC–MS for discrimination between the secondary metabolites of wild and cultivated South Korean medicinal foods

Depolymerization and Activation of Lignin: Current State of Knowledge and Perspectives

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