Lignin pyrolysis reactions

Kawamoto, Hiroyuki

doi:10.1007/s10086-016-1606-z

Cited by 451 publications

(305 citation statements)

References 113 publications

(192 reference statements)

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“…The greater proportion of phenolics for the inertinite-rich sample ( Table 2) may also be consistent with a fire-origin for the major inertinite macerals of this sample, as concluded by Moroeng et al (2018a). This is based on the fact that pyrolysis experiments using ligninrich wood at temperatures below 400°C produces phenolic moieties (Asmadi et al 2011;Kawamoto 2017). However, the phenolic moieties produced during the pyrolysis experiments are methoxy-substituted.…”

Section: Comparison Of Organic Geochemistry Of the Vitrinite-rich Andsupporting

confidence: 77%

Comparative study of a vitrinite-rich and an inertinite-rich Witbank coal (South Africa) using pyrolysis-gas chromatography

Moroeng

Mhuka

Nindi

et al. 2019

Int J Coal Sci Technol

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This study aims to compare iso-rank vitrinite-rich and inertinite-rich coal samples to understand the impact of coal-forming processes on pyrolysis chemistry. A medium rank C bituminous coal was density-fractionated to create a vitrinite-rich and an inertinite-rich sub-sample. The vitrinite-rich sample has 83 vol% total vitrinite (mineral-matter-free basis), whereas the inertinite-rich counterpart has 66 vol% total inertinite. The vitrinite-rich sample is dominated by collotelinite and collodetrinite. Fusinite, semifusinite, and inertodetrinite are the main macerals of the inertinite-rich sample. Molecular chemistry was assessed using a pyrolysis gas chromatograph (py-GC) equipped with a thermal desorption unit coupled to a time of flight mass spectrometer (MS) (py-GC/MS) and solid-state nuclear magnetic resonance ( 13 C CP-MAS SS NMR). The pyrolysis products of the coal samples are generally similar, comprised of low and high molecular weight alkanes, alkylbenzenes, alkylphenols, and alkyl-subtituted polycyclic aromatic hydrocarbons, although the vitrinite-rich sample is chemically more diverse. The lack of diversity exhibited by the inertinite-rich sample upon pyrolysis may be interpreted to suggest that major components were heated in their geologic history. Based on the 13 C CP-MAS SS NMR analysis, the inertinite-rich sample has a greater fraction of phenolics, reflected in the py-GC/MS results as substituted and unsubstituted derivatives. The greater abundance of phenolics for the inertinite-rich sample may suggest a fire-related origin for the dominant macerals of this sample. The C 2 -alkylbenzene isomers (p-xylene and o-xylene) were detected in the pyrolysis products for the vitrinite-rich and inertinite-rich samples, though more abundant in the former. The presence of these in both samples likely reflects common source vegetation for the dominant vitrinite and inertinite macerals.

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Section: Comparison Of Organic Geochemistry Of the Vitrinite-rich Andsupporting

confidence: 77%

Comparative study of a vitrinite-rich and an inertinite-rich Witbank coal (South Africa) using pyrolysis-gas chromatography

Moroeng

Mhuka

Nindi

et al. 2019

Int J Coal Sci Technol

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“…There was also char formation through some of the intermediates. In practice, tar or coke formation was the main issue in thermal process development …”

Section: Expanding the Use Of Lignin Through Depolymerizationmentioning

confidence: 99%

The current and emerging sources of technical lignins and their applications

Rao

2018

Biofuels Bioprod Bioref

161

142

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Technical lignins are bulk feedstocks. They are generated as byproducts from pulping or cellulosic ethanol production. Since lignin undergoes significant structural changes in the chemical and physical treatments, all technical lignins are unique in terms of chemical structure, molecular weight, polydispersity, and impurity profile. Kraft lignin is potentially the largest source of technical lignin as new isolation technologies have been implemented on industrial scale in recent years. Lignosulfonate has been an integral product in sulfite pulping biorefinery. It has a well-established market in construction industry. Organosolv-like lignin production is increasing as cellulosic ethanol has been promoted as the substitute of fossil fuel. It may have unique applications because it has low molecule weight and is free from sulfur. Technical lignin application is expected to expand as the characteristics are improved with fractionation or chemical modification. The application of technical lignin has been focusing on developing products equivalent to those made by petroleum chemicals. The recent development in technical lignin supply should increase its market share as additives in polyurethanes and as the substitute of phenol-formaldehyde adhesives. Quality improvement of technical lignin may also encourage the study of lignin as an alternative feedstock for carbon fiber. In addition, technical lignin depolymerization has been extensively explored to provide renewable aromatic chemicals. Starting from controlled pyrolysis and thermal liquefaction as the baseline technologies, many different chemical depolymerization have been invented with a wide range of underlying chemical principles.

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“…Among these components, lignin exhibits a random three-dimensional structure with the p-hydroxyphenyl, syringyl, and guaiacyl units; in addition, it is major renewable source of aromatic compounds [2][3][4][5][6][7]. Meanwhile, pyrolysis produces combustible gases, liquid fuels, and chemical feedstock directly from lignin or lignocellulosic biomass [8][9][10][11][12][13][14][15]. The pyrolysis is roughly divided into two steps: the primary heterogeneous pyrolysis involving the volatilization from biomass solids and the secondary homogeneous vapor-phase cracking of the released volatiles [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Computational Study on the Thermal Decomposition of Phenol‐Type Monolignols

Furutani

Dohara

Kudo

et al. 2018

Int J of Chemical Kinetics

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A detailed chemical kinetic model has been developed to theoretically predict the pyrolysis behavior of phenol‐type monolignol compounds (1‐(4‐hydroxyphenyl)prop‐2‐en‐1‐one, HPP; p‐coumaryl alcohol, 3‐hydroxy‐1‐(4‐hydroxyphenyl)propan‐1‐one, HHPP; 1‐(4‐hydroxyphenyl)propane‐1,3‐diol, HPPD) released from the primary heterogeneous pyrolysis of lignin. The possible thermal decomposition pathways involving unimolecular decomposition, H‐addition, and H‐abstraction by H and CH3 radicals were investigated by comparing the activation energies calculated at the M06–2X/6–311++G(d,p) level of theory. The results indicated that all phenol‐type monolignol compounds convert to phenol by side‐chain cleavage. p‐Coumaryl alcohol decomposes into phenol via the formation of 4‐vinylphenol, whereas HPP, HHPP, and HPPD decompose into phenol via the formation of 4‐hydroxybenzaldehyde. The pyrolytic pathways focusing on the reactivity of the hydroxyl group in HPP and producing cyclopentadiene (cyc‐C5H6) were also investigated. The transition state theory (TST) rate constants for all the proposed elementary reaction channels were calculated at the high‐pressure limit in the temperature range of 300–1500 K. The kinetic analysis predicted the two favorable unimolecular decomposition pathways in HPP: the one is the dominant channel below 1000 K to produce cyc‐C5H6, and the other is above 1000 K to yield phenol (C6H5OH).

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Lignin pyrolysis reactions

Cited by 451 publications

References 113 publications

Comparative study of a vitrinite-rich and an inertinite-rich Witbank coal (South Africa) using pyrolysis-gas chromatography

Comparative study of a vitrinite-rich and an inertinite-rich Witbank coal (South Africa) using pyrolysis-gas chromatography

The current and emerging sources of technical lignins and their applications

Computational Study on the Thermal Decomposition of Phenol‐Type Monolignols

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