Influence of reaction conditions on solvolysis of organosolv lignin using water and green organic co-solvents as reaction medium

Hashmi, Syed Farhan; Meriö-Talvio, Heidi; Ruuttunen, Kyösti; Sixta, Herbert

doi:10.1016/j.fuproc.2019.106200

Cited by 15 publications

(10 citation statements)

References 41 publications

(64 reference statements)

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“…Successive fractionation is effective in obtaining lignin fragments, derived from different sources and extraction methods, with diversity in the main connections and functional groups. Some advantages reported in the literature include the increase by fractionation, of some active functional groups, such as phenolic hydroxyl groups and methoxyl groups. − In this case, the content of methoxyl groups and phenolic hydroxyl groups had a tendency to decrease as the molar mass of lignin increased . In practically all works that presented results of polydispersity, the reduction of the same after fractionation as been reported, as it is in the case of the work of Song et al Authors highlighted that purity and thermal stability were also improved.…”

Section: Lignin Fractionation Methodsmentioning

confidence: 89%

Lignin Fractionation Methods: Can Lignin Fractions Be Separated in a True Industrial Process?

Rodrigues

Lima

Araújo

et al. 2021

Ind. Eng. Chem. Res.

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Lignin is among one of the largest natural resources in the world, with aromatic structures that can serve as a raw material in the synthesis of high value-added chemicals, the production of bioenergy, and the development of carbon-based products, among others. A better understanding of the chemical structure of lignin and its valorization methods is necessary to overcome current technological challenges for industrial scale applications. The main challenge found to provide the most abundant source of aromatics in the world is the fractionation of lignin. Current studies propose a way to fractionate lignin to obtain more homogeneous and less complex fractions, because of the fact that aromatic compounds are essential intermediates in the manufacture of polymers, and lignin is the main source of biologically aromatic-based substrates. Numerous review articles have addressed research aimed at understanding the structure of lignin, however, a limited focus has been given to its fractionation methods. This article aims to review papers published in recent years using different lignin fractionation techniques, focusing on the four main types of fractionations: in organic solvents, gel permeation chromatography in preparatory scale, ultrafiltration and precipitation by varying acid gradient. This a Review summarizes the most recent innovations in the area of biorefineries for the chemical valorization of lignin derived from various botanical sources through different fractionation methods.

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Section: Lignin Fractionation Methodsmentioning

confidence: 89%

Lignin Fractionation Methods: Can Lignin Fractions Be Separated in a True Industrial Process?

Rodrigues

Lima

Araújo

et al. 2021

Ind. Eng. Chem. Res.

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“…In general, low boiling alcohols or a mixture of water and low boiling alcohols are used ( possibility to quench the free lignin radicals by their hydrogen-donating behavior) or other green solvents such as DESs. [217][218][219] Guo et al investigated the reductive depolymerization of several KLs (6 g L −1 ) at 220 °C (20 h-48 h) with C 1 -C 3 alcohol/water (7 : 3 v/v) mixtures under autogenous pressure. MeOH and ethanol systems were less likely to produce monomers and dimers.…”

Section: Biocatalytic Depolymerizationmentioning

confidence: 99%

“…The addition of more 2-MTHF or water resulted in higher residual lignin and/or char content of 3.1 wt% residual lignin and 10.4 wt% char and 23.7 wt% residual lignin and 2.3 wt% char and lower depolymerized lignin yields of 75.8 wt% and 57.7 wt%, respectively. Increasing the reaction temperature from 270 °C to 310 °C led to a small increase in the depolymerized lignin yield to 88.6 wt% 217 Erdocia et al applied high temperature (300 °C, 40 min) to obtain supercritical polar solvents to convert 3 different OLs (acetosolv, formosolv and acetosolv/formosolv) from olive tree pruning (lignin loading of 1 : 20 w/v) under N 2 into phenolic monomers. The oil yield (>20 wt%) was dependent on the lignin (source and delignification technique) and solvents employed.…”

Section: Biocatalytic Depolymerizationmentioning

confidence: 99%

Sustainable lignin modifications and processing methods: green chemistry as the way forward

et al. 2023

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“…As the M w of a large part of the sample is too high for optimal application, controlled depolymerization of especially the large lignin fragments to a lower molar mass may have potential to tailor lignin characteristics for a better control over its solubility, reactivity, and thermal properties. Most literature examples however focus on deep polymerization and target the production of monomeric phenolics via full lignin depolymerization using thermochemical, oxidative, reductive, photocatalytic, and biochemical processes. − Only very few studies report on, e.g., optimization of the oligomer product instead. , Indeed, the strategy of tailoring macromolecular properties via partial depolymerization of an isolated lignin (and its fractions) remains to be demonstrated. Within the deep depolymerization examples, reductive approaches have gained particular interest as they achieve high monomer yields, in particular when applied in a lignin-first-type strategy.…”

Section: Introductionmentioning

confidence: 99%

Reductive Partial Depolymerization of Acetone Organosolv Lignin to Tailor Lignin Molar Mass, Dispersity, and Reactivity for Polymer Applications

Smit

Dezaire

Riddell

et al. 2023

ACS Sustainable Chem. Eng.

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Lignin partial depolymerization by reduction (PDR) was developed as a strategy to tailor a technical lignin's molar mass and reduce its heterogeneity and to potentially increase the reactivity of lignin hydroxyl groups in polymer applications such as PU foams and coatings. The process aims to cleave remaining lignin β-O-4 linkages, thereby reducing the molar mass of large lignin fragments and overall lignin dispersity. Acetone organosolv lignin from pilot-scale fractionation of industrial-size wood chips was depolymerized using methanol, a Ru/C catalyst, and externally supplied hydrogen. The effect of reaction temperatures (in the presence and absence of the catalyst) was fully detailed using SEC, 31 P NMR, and 2D-HSQC NMR analyses of the depolymerized lignin. The Ru/C catalyst promoted molar mass reduction by hydrogenolysis and slightly increased the lignin aliphatic OH content. Process parameter screening showed effective depolymerization at high lignin concentrations but required relatively high catalyst loadings. PDR depolymerization efficiency proved to be dependent on the technical lignin's quality. A less-condensed lignin with a higher β-O-4 content showed improved ether cleavage, yielding a lower lignin molar mass after PDR and increased formation of 4-n-propanol end groups. Overall, the PDR process provides control over key lignin characteristics, which in turn offers potential to tailor biobased polymer properties for various applications.

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Influence of reaction conditions on solvolysis of organosolv lignin using water and green organic co-solvents as reaction medium

Cited by 15 publications

References 41 publications

Lignin Fractionation Methods: Can Lignin Fractions Be Separated in a True Industrial Process?

Lignin Fractionation Methods: Can Lignin Fractions Be Separated in a True Industrial Process?

Sustainable lignin modifications and processing methods: green chemistry as the way forward

Reductive Partial Depolymerization of Acetone Organosolv Lignin to Tailor Lignin Molar Mass, Dispersity, and Reactivity for Polymer Applications

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