Influence of RANEY Nickel on the Formation of Intermediates in the Degradation of Lignin

Forchheim, D.; Hornung, Ursel; Kempe, Philipp; Kruse, Andrea; Steinbach, D.

doi:10.1155/2012/589749

Cited by 38 publications

(57 citation statements)

References 26 publications

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“…Fig. 4 shows the Arrhenius-plot of this reaction in water at different temperatures [112]. There is a kink between the sub-critical and near-critical data indicating a change in the reaction mechanism.…”

Section: The Role Of Water In the Different Processesmentioning

confidence: 97%

“…This is remarkable, because the chemical mechanism seems to be an ionic one at hydrothermal conditions [2] but which cannot be ionic at dry conditions with missing stabilization by water as a solvent. As an assumption, water as solvent opens a low-temperature, ionic [115] and via pyrolysis [116] (Copyright © 2012 Daniel Forchheim et al [112]). pathways to products, which are formed via free radical reaction in dry pyrolysis.…”

Section: The Role Of Water In the Different Processesmentioning

confidence: 99%

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Water – A magic solvent for biomass conversion

Kruse

Dahmen

2015

The Journal of Supercritical Fluids

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254

148

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Section: The Role Of Water In the Different Processesmentioning

confidence: 97%

Section: The Role Of Water In the Different Processesmentioning

confidence: 99%

Water – A magic solvent for biomass conversion

Kruse

Dahmen

2015

The Journal of Supercritical Fluids

Self Cite

254

148

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“…Table 1 presents the predominant bonds in lignin. According to Forchheim et al [14], reactions including mild alkylation, hydro deoxygenation, reploymerization, and depolymerisation are predominant in lignin HTL. Liguori and Barth [15], reported reactions like hydro-deoxygenated, demethylated and demethoxylated at the ether bond positions.…”

Section: Lignin Composition and Chemistrymentioning

confidence: 99%

“…Recalling that, β-O-4 bond is the predominant in lignin structure, large quantity of guaiacol is expected during HTL. The production of guaiacol depends on the cleavage of C-O and C-C bonds during lignin degradation [14]. Increasing reaction temperature reduces the yield of guaiacol-derivatives at the expense of their benzendiol counterparts (Catechol).…”

Section: Guaiacolmentioning

confidence: 99%

Lignin Hydrothermal Liquefaction into Bifunctional Chemicals: A Concise Review

Alhassan¹,

Hornung²,

Bugaje³

2020

Biorefinery Concepts, Energy and Products

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Lignin, the second largest biomass after cellulose is underutilized. Yet, it remains the only natural source of aromatic, and phenolic compounds. It is imperative to, amidst the expanding interest on biomass conversion, to accord the necessary attention towards lignin degradation into value added chemicals. Specifically, its phenyl, guaiacyl, and syringyl derivatives. Understanding lignin degradation chemistry, goes a long way in its selective valorization into fuels and chemicals via thermochemical routes such as hydrothermal liquefaction (HTL). Therefore, development of technologies targeting value addition of products and by-products from lignin, would undoubtedly give way to emerging markets in the industry. Previous review papers focused on the general HTL of biomass, food waste, algae, and their model compounds. However, review on HTL of lignin is scarcely available. This paper presents the detailed literature analyses of the current trend in lignin degradation via HTL. Effect of HTL conditions including temperature, heating rate and catalyst has been reviewed. In-depth discussion on use of ionic liquids as catalyst for HTL of lignin has also been compiled. Other lignin degradation techniques such as pyrolysis and hydrolysis were also discussed. This is aimed at bringing together an up-to-date information on lignin degradation into selected chemical intermediates.

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“…Guaiacol, as another representative lignin depolymerization product, contains abundant phenolic and methoxy groups, which are the basic functional elements of lignin matrix [50]. HDO of guaiacol was widely studied over Ni/CNTs [44,58], Ni/HZSN-5 [46], Raney Ni [59], Ni/Al-MCM-41 [49], Ni/CeO 2 [60], and Ni/MgO catalyst [50]. Escalona and co-workers studied the HDO of guaiacol over Ni/CNTs at 300 • C under 5 MPa and found that the hydrogenation (HYD) of the aromatic ring of guaiacol occurred initially and subsequently demethoxylation (DMO) was observed [44].…”

Section: Monometallic Ni-based Catalysts For Hdo Of Ligninmentioning

confidence: 99%

Lignin Valorizations with Ni Catalysts for Renewable Chemicals and Fuels Productions

Chen

Guan

Tsang³

et al. 2019

Catalysts

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Energy and fuels derived from biomass pose lesser impact on the environmental carbon footprint than those derived from fossil fuels. In order for the biomass-to-energy and biomass-to-chemicals processes to play their important role in the loop of the circular economy, highly active, selective, and stable catalysts and the related efficient chemical processes are urgently needed. Lignin is the most thermal stable fraction of biomass and a particularly important resource for the production of chemicals and fuels. This mini review mainly focuses on lignin valorizations for renewable chemicals and fuels production and summarizes the recent interest in the lignin valorization over Ni and relevant bimetallic metal catalysts on various supports. Particular attention will be paid to those strategies to convert lignin to chemicals and fuels components, such as pyrolysis, hydrodeoxygenation, and hydrogenolysis. The review is written in a simple and elaborated way in order to draw chemists and engineers' attention to Ni-based catalysts in lignin valorizations and guide them in designing innovative catalytic materials based on the lignin conversion reaction.Catalysts 2019, 9, 488 2 of 39 processes to play their important role in the loop of the circular economy, first, the process must be energy efficient itself [2]. Second, according to Anastas's second principle [3], atom economy should be maximized and excess starting materials which will not be contained in the final product should be avoided. Thus, developing highly active and selective catalysts and enzymes is an urgent need. Current technology for lignocellulosic valorization includes biochemical fermentation, chemical and thermochemical methods using enzymes and metal catalysts, respectively. Thermochemical methods, including combustion, pyrolysis, and gasification, and chemical methods, such as hydrodeoxygenation (HDO), hydrogenolysis, and oxidative cleavage, have the advantages of higher throughputs due to the short reaction time, and thus are more suitable for commercialized and industrialized scale-up.Woody and herbaceous biomasses are large polymeric networks consisting of ca. 35-50% cellulose, 25-30% hemicellulose (glucomannan and glucuronoxylan), and 15-30% of lignin (macromolecular polymer networks with interconnected phenylpropane and phenol units with various formula, e.g., (C 31 H 34 O 11 ) n ) by weight. Lignin is one of the most thermal stable fractions and a particularly important resource for the production of chemicals and fuels. With careful design of the metal catalysts, either aromatic platform molecules, or fuels components such as naphthenes, can be preferentially produced in high yields and with high selectivity.Over the past decade, numerous monometallic and bimetallic metal catalysts using both precious and base metal precursors on various supports have been reported to successfully convert lignin into valuable products. Transition metals such as Ni (price = US$ 12.628/kg as of April 2019) are much more economically viable than precious metals...

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Influence of RANEY Nickel on the Formation of Intermediates in the Degradation of Lignin

Cited by 38 publications

References 26 publications

Water – A magic solvent for biomass conversion

Water – A magic solvent for biomass conversion

Lignin Hydrothermal Liquefaction into Bifunctional Chemicals: A Concise Review

Lignin Valorizations with Ni Catalysts for Renewable Chemicals and Fuels Productions

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