Revealing G-lignin model compounds pyrolysis behavior: β-O-4 and 5-5′ dimer and trimer

Wang, Lei; Yin, Jun; Jiang, Jungang; Zhang, Yifan; Song, Mingyao; Zhang, Ran; Dong, Zhiguo; Yang, Haiping; Yu, Hongbo

doi:10.1016/j.fuel.2022.123531

Cited by 17 publications

(5 citation statements)

References 42 publications

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“…This information complements the other study, in which the pyrolysis of Gβ2 was investigated at much higher temperatures, 450, 550, 650, and 750 °C [31]. In contrast to our study, no dimers were detected in those high severity conditions, being replaced with catechols resulting from the scission of the other ether bond, within the methoxy group of Gβ2 [31]. The other study that investigated this process did not find any products but guaiacol at 200 and even 300 °C.…”

Section: Stability Toward Mild Solvent-free Pyrolysissupporting

confidence: 83%

“…Figure 5 shows the Pyr-GC-MS TIC chromatograms obtained at three temperatures, 150, 200, and 250 °C. This information complements the other study, in which the pyrolysis of Gβ2 was investigated at much higher temperatures, 450, 550, 650, and 750 °C [31]. In contrast to our study, no dimers were detected in those high severity conditions, being replaced with catechols resulting from the scission of the other ether bond, within the methoxy group of Gβ2 [31].…”

Section: Stability Toward Mild Solvent-free Pyrolysissupporting

confidence: 80%

“…Figure 5 shows the Pyr-GC-MS TIC chromatograms obtained at three temperatures, 150, 200, and 250 • C. This information complements the other study, in which the pyrolysis of Gβ2 was investigated at much higher temperatures, 450, 550, 650, and 750 • C [31]. In contrast to our study, no dimers were detected in those high severity conditions, being replaced with catechols resulting from the scission of the other ether bond, within the methoxy group of Gβ2 [31]. The other study that investigated this process did not find any products but guaiacol at 200 and even 300 • C. Perhaps, the use of transfer lines in the Pyr-GC-MS setup precluded the detection of dimers and other less volatile products [32].…”

Section: Stability Toward Mild Solvent-free Pyrolysissupporting

confidence: 74%

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Stability and Reactivity of Guaiacylglycerol-β-Guaiacyl Ether, a Compound Modeling β-O-4 Linkage in Lignin

Rabiei,

Simons,

Folkmanova

et al. 2024

Separations

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Lignin, a complex and abundant biopolymer, is a major constituent of plant cell walls. Due to its chemical and structural complexity, lignin degradation is a challenging task for both natural and engineered systems. Therefore, investigation of lignin degradation using so called “model compounds” has been the focus of many research efforts in recent years. This study addresses the utility of guaiacylglycerol-β-guaiacyl ether (Gβ2) as a model compound for evaluating the β-O-4 bond cleavage under diverse thermal and aqueous medium conditions. Experimental conditions included varied pH (3–10), microbial biodegradation, subcritical water environment (150–250 °C), and mild pyrolysis (150–250 °C). A high-performance liquid chromatography with high-resolution mass spectrometry was employed for accurate detection and quantification of both Gβ2 and its degradation/modification products in an aqueous environment. Pyrolysis experiments were performed using gas chromatography-mass spectrometry analysis with a pyrolyzer. The results showed that Gβ2 remained stable under exposure to moderate pH and several bacterial strains, which were successfully used previously for biodegradation of other recalcitrant pollutants. We report, for the first time, differing Gβ2 breakdown pathways for subcritical water treatment vs. pyrolysis under an inert atmosphere. The scientific novelty lies in the presentation of differences in the degradation pathways of Gβ2 during subcritical water treatment compared to pyrolysis in an inert atmosphere, with water playing a key role. The observed differences are ascribed to the suppression of homolytic reactions by water as a solvent.

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Section: Stability Toward Mild Solvent-free Pyrolysissupporting

confidence: 83%

Section: Stability Toward Mild Solvent-free Pyrolysissupporting

confidence: 80%

Section: Stability Toward Mild Solvent-free Pyrolysissupporting

confidence: 74%

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Stability and Reactivity of Guaiacylglycerol-β-Guaiacyl Ether, a Compound Modeling β-O-4 Linkage in Lignin

Rabiei,

Simons,

Folkmanova

et al. 2024

Separations

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“…The comparison of the relative yield of pyrolysis products from the pulp versus wood could also give a hint about the origin of the products; for instance, guaiacol (G 1) is thought to be mainly produced by the direct breaking of β-O-4 bonds [39,40] or of 5-5 condensation linkages [41]. The fact that delignification consists mainly in depleting β-O-4 linkages and that guaiacol is enriched in pulp compared to wood (Table 1) points to the 5-5 bond, the second most abundant inter-unit linkage in softwood lignin and more resistant to degradation, as the guaiacol source.…”

Section: Pulp Residual Lignin and Wood Have Different Patterns Of Pyr...mentioning

confidence: 99%

Analytical Pyrolysis as a Tool to Assess Residual Lignin Content and Structure in Maritime Pine High-Yield Pulp

Alves¹,

Graça²,

Rodrígues³

2022

Forests

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The residual lignin content of unbleached maritime pine (Pinus pinaster Aiton) Kraft pulps was assessed by analytical pyrolysis (Py-lignin) and the results were compared to the Klason lignin content and kappa number. Thirty samples, each from an individual tree, were delignified under identical conditions. The residual lignin content of the pulps varied widely as assessed by Py-lignin (5.9%–9.2%), Klason (8.2–15.1), and kappa number (59–112). Despite a systematic difference between Py-lignin and Klason, they were strongly correlated (R2 = 0.90). The H/G ratio of the residual pulp lignin ranged from 0.145 to 0.195, with a mean of 0.165, which is more than two times the average H/G ratio of Maritime pine wood lignin (0.064). The results show that Kraft pulping, which selectively degrades lignin with more labile inter-unit links, changed the pattern of pyrolysis products of pulp lignin considerably and, consequently, its structure. This pattern shows an enrichment in H-lignin-derived products, namely phenol, p-cresol, and m-cresol, and in some G-lignin-derived products such as guaiacol and 4-mthylguaiacol, and a decrease in coniferylaldehyde, homovanillin, and eugenol. Principal component analysis (PCA) of the G- and H-lignin-derived pyrolysis products shows that pulps are distributed along PC 1 based on their residual lignin content. The loadings plot shows that this separation is mainly due to a small number of G-lignin products, including 4-methyl guaiacol, 4-vinyl guaiacol, isoeugenol (trans), and guaiacol, which are more abundant in pulps with higher residual lignin content. The obtained results show that analytical pyrolysis is an appropriate method for quantifying the residual lignin content and H/G ratio of unbleached Kraft pulps and provide information regarding how lignin is degraded during the pulping process.

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“…Massive studies have focused on lignin pyrolysis using different techniques such as TGA (thermogravimetric analysis), Py-GC/MS (pyrolysis-gas chromatograph/mass spectroscopy) and fixed-/fluidized-bed reactors, and the products evolution was investigated comprehensively [ 38 – 41 ]. For deeply understanding the pyrolysis mechanism, some studies also used lignin-derived model compounds as pyrolyzed subjects, revealing that several linkages cleavage (such as C β –O and C α –C β ) occurred simultaneously [ 42 , 43 ].…”

Section: Introductionmentioning

confidence: 99%

A review on lignin pyrolysis: pyrolytic behavior, mechanism, and relevant upgrading for improving process efficiency

2022

Biotechnol Biofuels

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Lignin is a promising alternative to traditional fossil resources for producing biofuels due to its aromaticity and renewability. Pyrolysis is an efficient technology to convert lignin to valuable chemicals, which is beneficial for improving lignin valorization. In this review, pyrolytic behaviors of various lignin were included, as well as the pyrolytic mechanism consisting of initial, primary, and charring stages were also introduced. Several parallel reactions, such as demethoxylation, demethylation, decarboxylation, and decarbonylation of lignin side chains to form light gases, major lignin structure decomposition to generate phenolic compounds, and polymerization of active lignin intermediates to yield char, can be observed through the whole pyrolysis process. Several parameters, such as pyrolytic temperature, time, lignin type, and functional groups (hydroxyl, methoxy), were also investigated to figure out their effects on lignin pyrolysis. On the other hand, zeolite-driven lignin catalytic pyrolysis and lignin co-pyrolysis with other hydrogen-rich co-feedings were also introduced for improving process efficiency to produce more aromatic hydrocarbons (AHs). During the pyrolysis process, phenolic compounds and/or AHs can be produced, showing promising applications in biochemical intermediates and biofuel additives. Finally, some challenges and future perspectives for lignin pyrolysis have been discussed.

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Revealing G-lignin model compounds pyrolysis behavior: β-O-4 and 5-5′ dimer and trimer

Cited by 17 publications

References 42 publications

Stability and Reactivity of Guaiacylglycerol-β-Guaiacyl Ether, a Compound Modeling β-O-4 Linkage in Lignin

Stability and Reactivity of Guaiacylglycerol-β-Guaiacyl Ether, a Compound Modeling β-O-4 Linkage in Lignin

Analytical Pyrolysis as a Tool to Assess Residual Lignin Content and Structure in Maritime Pine High-Yield Pulp

A review on lignin pyrolysis: pyrolytic behavior, mechanism, and relevant upgrading for improving process efficiency

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