Protected lignin biorefining through cyclic extraction: gaining fundamental insights into the tuneable properties of lignin by chemometrics

Karlsson, Maria; Vegunta, Vijaya Lakshmi; Deshpande, Raghu; Lawoko, Martin

doi:10.1039/d1gc04171a

Cited by 17 publications

(33 citation statements)

References 42 publications

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“…Lignin solubility changes with the pH of the solution, and precipitates. As examples of these methods: (i) the lignin is dissolved in NaOH at pH 12 and by HNO 3 the LNPs precipitate [102]; (ii) the lignin is dissolved in ethylene glycol and the LNPs are precipitated by adding hydrochloric acid [95]. The use of an acid to precipitate the LNP makes the process more expensive and dangerous, but the acid can be recovered, and the method has the advantage of attaining well-defined LNP with a good shape and stability [58].…”

Section: Techniques Used For the Synthesis Of Lnpmentioning

confidence: 99%

“…The first one is about lignin's variability in nature that is quite heterogeneous (as already mentioned in this chapter); therefore, its isolation will produce a mixture of products, apart from being a challenging task and less economically feasible to purify all the different compounds for further applications [45,71]. The second point is related to the lignin fractionation methodologies that yield complex condensed lignin, which limits its high-value applicability [71,94], difficulties in attaining lignin in high yield and with good chemical and physical properties (e.g., molecular weight distribution, solubility, reactivity and number of functional groups), and with quality (in relation to the inter-units linkages, condensed lignin is not attractive) [43,95]. The third point is associated with LNP production and their adequate stabilization for different applications [96].…”

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confidence: 99%

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Lignin as Feedstock for Nanoparticles Production

Lourenço¹,

Gominho²

2023

Lignin - Chemistry, Structure, and Application

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Lignin is an interesting natural polymer with characteristics that contribute for the development and growth of plants. Lignin presents high variability associated with the diversity of plants, which presents great challenges for its recovery after delignification (technical lignin), because lignin is prone to irreversible degradation, producing recalcitrant condensed structures that are difficult to disassemble afterward. Although researchers have made efforts to obtain lignin in high yields and with good characteristics for specific uses, this is not an easy task. The mind-set has changed and new biorefinery concepts are emerging, where lignin is the primary goal to achieve, and the so-called lignin-first approach has arisen. Lignin can be obtained firstly to prevent structural degradations, enabling an efficient and highly selectivity of the lignin monomers. Therefore, this concept places lignin and its valorization at the head of the biorefinery. However, lignin valorization is still a challenge, and to overcome this, lignin nanoparticles (LNPs) production presents a good way to achieve this goal. This chapter presents a resume of the several techniques to attain lignin, how to produce LNPs, and their possible applications (from pharmaceutical to the automobile and polymer industries).

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Section: Techniques Used For the Synthesis Of Lnpmentioning

confidence: 99%

mentioning

confidence: 99%

Lignin as Feedstock for Nanoparticles Production

Lourenço¹,

Gominho²

2023

Lignin - Chemistry, Structure, and Application

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“…However, due to the heterogeneity of lignin, its chemical and physical properties still require deeper investigations. The increased fundamental knowledge about lignin properties is of relevance for understanding the reactivity of lignin under certain process conditions, predicting reactions and subsequently developing valorization strategies for extracted lignin …”

Section: Introductionmentioning

confidence: 99%

“…In our earlier work, , we developed an ethanol-based organosolv lignin biorefinery process using an additive-free physical protection concept, where the native lignin structure is preserved to a high degree. The physical protection is attributed to the cyclic extraction methodology.…”

Section: Introductionmentioning

confidence: 99%

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Lignin Structure and Reactivity in the Organosolv Process Studied by NMR Spectroscopy, Mass Spectrometry, and Density Functional Theory

et al. 2023

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There is need for well-defined lignin macromolecules for research related to their use in biomaterial and biochemical applications. Lignin biorefining efforts are therefore under investigation to meet these needs. The detailed knowledge of the molecular structure of the native lignin and of the biorefinery lignins is essential for understanding the extraction mechanisms as well as chemical properties of the molecules. The objective of this work was to study the reactivity of lignin during a cyclic organosolv extraction process adopting physical protection strategies. As references, synthetic lignins obtained by mimicking the chemistry of lignin polymerization were used. State-of-the-art nuclear magnetic resonance (NMR) analysis, a powerful tool for the elucidation of lignin inter-unit linkages and functionalities, is complemented with matrix-assisted laser desorption/ionization-time-of-flight-mass spectrometry (MALDI-TOF MS), to gain insights into linkage sequences and structural populations. The study unraveled interesting fundamental aspects on lignin polymerization processes, such as identifications of molecular populations with high degrees of structural homogeneity and the emergence of branching points in lignin structure. Furthermore, a previously proposed intramolecular condensation reaction is substantiated and new insights into the selectivity of this reaction are introduced and supported by density functional theory (DFT) calculations, where the important role of intramolecular π−π stacking is emphasized. The combined NMR and MALDI-TOF MS analytical approach, together with computational modeling, is important for deeper fundamental lignin studies and will be further exploited.

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Rapid Lignin Thermal Property Prediction through Attenuated Total Reflectance‐Infrared Spectroscopy and Chemometrics

Riddell,

Lindner,

de Peinder

et al. 2024

ChemSusChem

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To expedite the valorisation of lignin as a sustainable component in materials applications, rapid and generally available analytical methods are essential to overcome the bottleneck of lignin characterisation. Where features of a lignin’s chemical structure have previously been found to be predicted by Partial Least Squares (PLS) regression models built on Infrared (IR) data, we now show for the first time that this approach can be extended to prediction of the glass transition temperature (Tg), a key physicochemical property. This methodology is shown to be convenient and more robust for prediction of Tg than prediction through empirically‐derived relationships (e.g., Flory‐Fox). The chemometric analysis provided root mean squared errors of prediction (RMSEP) as low as 10.0 °C for a botanically, and a process‐diverse set of lignins, and 6.2 °C for kraft‐only samples. The PLS models could separately predict both the Tg as well as the degree of allylation (%allyl) for allylated lignin fractions, which were all derived from a single lignin source. The models performed exceptionally well, delivering RMSEP of 6.1 °C, and 5.4 %, respectively, despite the conflicting influences of increasing molecular weight and %allyl on Tg. Finally, the method provided accurate determinations of %allyl with RMSEP of 5.2 %.

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Protected lignin biorefining through cyclic extraction: gaining fundamental insights into the tuneable properties of lignin by chemometrics

Abstract: Lignin is a renewable source of aromatics with great potential as substitute for fossil-based phenolic compounds that are used in several material applications. However, available technical lignins are heterogenic and...

Cited by 17 publications

References 42 publications

Lignin as Feedstock for Nanoparticles Production

Lignin as Feedstock for Nanoparticles Production

Lignin Structure and Reactivity in the Organosolv Process Studied by NMR Spectroscopy, Mass Spectrometry, and Density Functional Theory

Rapid Lignin Thermal Property Prediction through Attenuated Total Reflectance‐Infrared Spectroscopy and Chemometrics

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