Phenols and aromatics from fast pyrolysis of variously prepared lignins from hard- and softwoods

Custodis, Victoria B. F.; Bährle, Christian; Vogel, Frédéric; Bokhoven, Jeroen A. van

doi:10.1016/j.jaap.2015.07.018

Cited by 99 publications

(37 citation statements)

References 35 publications

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“…The appearance of these micro bubbles is indicative of vapor formation within the liquid phase via fragmentation reactions of ␤-O bonds to form phenols, alkoxy-ketones, and light gases [64].…”

Section: Behavior Of Organosolv Lignin During Pyrolysismentioning

confidence: 99%

Identification of the fractions responsible for morphology conservation in lignocellulosic pyrolysis: Visualization studies of sugarcane bagasse and its pseudo-components

Montoya

Pecha

Janna

et al. 2017

Journal of Analytical and Applied Pyrolysis

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a b s t r a c tPyrolysis of lignocellulosic materials typically form carbonaceous residues (chars) with structures similar to the starting material. However, previous studies reported in the literature have shown that fast pyrolysis of cellulose and lignin form a molten intermediate liquid resulting in chars with smooth surfaces and evidences of intense bubbling. The fraction responsible for morphology conservation during pyrolysis is not known. In this article, pyrolysis visualization studies were carried out with a fast camera on cellulose, xylan, Organosolv lignin (OL), milled wood lignin (MWL), and lignocellulosic sugarcane bagasse to identify the component responsible for morphological conservation. The materials were heated using a modified Pyroprobe with measured sample heating rates close to 100 • C/s. Our studies confirm that cellulose, lignin, and deashed xylan are completely transformed into an intermediate liquid; the intensity of bubbling for lignin was far superior that of cellulose. Xylan as received, however, only forms a small amount of intermediate liquid; it does not fully melt and maintains its general shape during pyrolysis. These results suggest that the presence of mineral matter is critical for lignocellulosic materials to retain their original morphology. We repeated the studies on raw bagasse and acid washed bagasse. The raw bagasse retains its morphology; the acid washed bagasse shrank dramatically, but was not completely converted into a liquid. Our results suggest that in addition to hemicellulose with the presence of ash, other biomass fractions or the different temperatures at which the different fractions melt and solidify could also be contributing to maintain the structure of the lignocellulosic material during pyrolysis.

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Section: Behavior Of Organosolv Lignin During Pyrolysismentioning

confidence: 99%

Identification of the fractions responsible for morphology conservation in lignocellulosic pyrolysis: Visualization studies of sugarcane bagasse and its pseudo-components

Montoya

Pecha

Janna

et al. 2017

Journal of Analytical and Applied Pyrolysis

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“…Klason lignin produced a higher quantity of phenols at temperatures exceeding 550 °C than organosolv and kraft lignin. The authors of this study hypothesized that in Klason lignin, the new C-C bonds formed by acid-catalyzed condensation between the aromatic C6 or C5 and carbonium ions formed stable radicals at higher temperatures, leading to relatively fewer rearrangement reactions of phenols (Dorrestijn et al 2000;Custodis et al 2015). FE-SEM Figure 6 shows the surface morphology of lignin samples after extraction by acetone/water (9:1).…”

Section: Py-gc-ms Analysismentioning

confidence: 99%

“…Compared to the control RML, the pyrolysis products of the SE degraded lignin (SEML) contained larger amounts of phenol. A related experiment was performed by Custodis et al (2015), who investigated fast pyrolysis of soft and hardwood lignin prepared by various methods. Klason lignin produced a higher quantity of phenols at temperatures exceeding 550 °C than organosolv and kraft lignin.…”

Section: Py-gc-ms Analysismentioning

confidence: 99%

The Critical Analysis of Catalytic Steam Explosion Pretreatment of Corn Stalk, Lignin Degradation, Recovery, and Characteristic Variations

Yang¹,

Li²,

Xu³

et al. 2016

BioResources

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The lignin degradation and its structural change as a result of catalytic steam explosion pretreatment can be considered of great importance for both the subsequent fermentation and the further utilization of the lignin fraction. This work investigated the degradation mechanism and change in the characteristics of lignin during dilute sulphuric-acid catalytic steam explosion (SE) pretreatment and ammonia catalytic steam explosion (AE) pretreatment of corn stalk. For this purpose, two types of lignin samples obtained from the two pretreatments of aqueous products and solid residues were fractionated, and they were then characterized by a series of comprehensive analyses that consisted of gas chromatography-mass spectroscopy (GC-MS), ion chromatography (IC), Fourier transform infrared (FT-IR), Carbon-13 nuclear magnetic resonance ( 13 C NMR), Carbon-Hydrogen two-dimensional heteronuclear single quantum coherence ( 13 C-1 H 2D HSQC), pyrolysis-GC-MS (Py-GC-MS), and field emission scanning electron microscopy (FE-SEM). Overall, the characteristic diversity of the lignin provides useful reference for highvalue applications of lignin.

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“…Model compounds are commonly studied to understand chemical upgrading and depolymerization and enable the study of a single bond or building block. Given the complexity and diversity of lignin, many chemical reactions and processes occur simultaneously during lignin treatment, so that specific behavior is generally hard to correlate to one chemical or physical property of the lignin . Model compounds, such as guaiacol and diphenylether, resemble a common intermediate (and building block) and the 4‐ O ‐5 bond.…”

Section: Introductionmentioning

confidence: 99%

How Inter‐ and Intramolecular Reactions Dominate the Formation of Products in Lignin Pyrolysis

Custodis

Hemberger

Bokhoven

2017

Chemistry A European J

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One of the key challenges in renewable chemical production is the conversion of lignin, especially by fast pyrolysis. The complexity of the lignin pyrolysis process has hindered the elucidation of the mechanism, inhibiting further industrial implementation. By combining pyrolysis of model compounds (4-phenoxyphenol and 2-methoxy-phenoxybenzene) with lignin bond characteristics both under vacuum and under realistic pressure conditions, the roles of inter- and intramolecular reactions were established. On the one hand, the stable 4-O-5 ether bond enables, without breaking, C-C bond formation and even directly forms naphthalene depending on the position and type of the substituent. p-Benzoquinone intermediates, on the other hand, are highly unstable at ambient pressure and directly decompose into coke and carbon monoxide. The system pressure (radical concentration) plays a crucial role in the dominant reaction mechanism by initiating intramolecular reactions, interfering with intramolecular reactions. H-transfer and recombination reactions suppress the decarbonylation of phenoxy radicals, thus yielding a very different product distribution.

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Phenols and aromatics from fast pyrolysis of variously prepared lignins from hard- and softwoods

Cited by 99 publications

References 35 publications

Identification of the fractions responsible for morphology conservation in lignocellulosic pyrolysis: Visualization studies of sugarcane bagasse and its pseudo-components

Identification of the fractions responsible for morphology conservation in lignocellulosic pyrolysis: Visualization studies of sugarcane bagasse and its pseudo-components

The Critical Analysis of Catalytic Steam Explosion Pretreatment of Corn Stalk, Lignin Degradation, Recovery, and Characteristic Variations

How Inter‐ and Intramolecular Reactions Dominate the Formation of Products in Lignin Pyrolysis

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