Chemicals from Lignin by Catalytic Fast Pyrolysis, from Product Control to Reaction Mechanism

Ma, Zhewen; Custodis,; Hemberger, Patrick; Bährle, Christian; Vogel, Frédéric; Jeschk, G; Ja, van Bokhoven

doi:10.2533/chimia.2015.597

Cited by 25 publications

(4 citation statements)

References 17 publications

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“…In the presence of a zeolite, phenol alkoxy compounds undergo dealkoxylation to form the corresponding aromatics and phenols. However, phenols are intermediates and are not easily further deoxygenated, therefore, only the lowest Si/Al zeolite with the highest fraction of acid sites is ideal to further convert them …”

Section: Resultssupporting

confidence: 65%

Optimization of the Reaction Conditions for Catalytic Fast Pyrolysis of Pretreated Lignin over Zeolite for the Production of Phenol

Ghosh

Asthana

et al. 2017

ChemCatChem

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The catalytic fast pyrolysis of lignin for the production of phenols over commercial zeolites was studied in‐depth. The results show that the production of phenols depended on several parameters, such as lignin pretreatment methods, pyrolysis temperature, zeolite structure and acidity, pyrolysis time, and feed‐to‐catalyst weight ratio. Lignin pretreatments had a significant influence on the liquid‐product distribution. Hydrogen chloride pretreatment of lignin increased the depolymerization of the lignin matrix, resulting in an increase of the liquid yield, as well as the phenol fraction. High temperature (e.g., 650 °C) and a fast heating rate (20 °C ms−1) were required to depolymerize lignin and increase the yield of liquid products, and large‐pore‐size zeolites (e.g., FAU) with Si/Al of approximately 15 favored the formation of phenols. A long pyrolysis time (20 s) was also beneficial for phenol to desorb from the catalyst. The medium feed‐to‐catalyst weight ratio of approximately 1:1 prevented further conversion of phenols to deoxygenated products such as aromatic hydrocarbons (benzene, toluene, and xylene).

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Section: Resultssupporting

confidence: 65%

Optimization of the Reaction Conditions for Catalytic Fast Pyrolysis of Pretreated Lignin over Zeolite for the Production of Phenol

Ghosh

Asthana

et al. 2017

ChemCatChem

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“…Similar to the methyl radical, other radical intermediates are expected to survive the few wall collisions within the reactor in the few millisecond transfer time to detection. Several indications point to a strong binding of the radicals to the catalyst surface or a rapid quenching before desorption: First, by using electron paramagnetic resonance (EPR) spectroscopy, Bährle et al 4243. showed a radical concentration enhancing effect during catalytic pyrolysis of lignin.…”

Section: Resultsmentioning

confidence: 99%

Understanding the mechanism of catalytic fast pyrolysis by unveiling reactive intermediates in heterogeneous catalysis

et al. 2017

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Catalytic fast pyrolysis is a promising way to convert lignin into fine chemicals and fuels, but current approaches lack selectivity and yield unsatisfactory conversion. Understanding the pyrolysis reaction mechanism at the molecular level may help to make this sustainable process more economic. Reactive intermediates are responsible for product branching and hold the key to unveiling these mechanisms, but are notoriously difficult to detect isomer-selectively. Here, we investigate the catalytic pyrolysis of guaiacol, a lignin model compound, using photoelectron photoion coincidence spectroscopy with synchrotron radiation, which allows for isomer-selective detection of reactive intermediates. In combination with ambient pressure pyrolysis, we identify fulvenone as the central reactive intermediate, generated by catalytic demethylation to catechol and subsequent dehydration. The fulvenone ketene is responsible for the phenol formation. This technique may open unique opportunities for isomer-resolved probing in catalysis, and holds the potential for achieving a mechanistic understanding of complex, real-life catalytic processes.

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“…Industrially, it is obtained as a byproduct in the production of cellulose-rich pulp fibers. The application potential of such macromolecules includes fields such as energy, chemicals, , and polymeric or carbon materials.…”

Section: Introductionmentioning

confidence: 99%

Tunable Thermosetting Epoxies Based on Fractionated and Well-Characterized Lignins

et al. 2018

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Here we report the synthesis of thermosetting resins from low molar mass Kraft lignin fractions of high functionality, refined by solvent extraction. Such fractions were fully characterized by P NMR, 2D-HSQC NMR, SEC, and DSC in order to obtain a detailed description of the structures. Reactive oxirane moieties were introduced on the lignin backbone under mild reaction conditions and quantified by simpleH NMR analysis. The modified fractions were chemically cross-linked with a flexible polyether diamine ( M ≈ 2000), in order to obtain epoxy thermosets. Epoxies from different lignin fractions, studied by DSC, DMA, tensile tests, and SEM, demonstrated substantial differences in terms of thermo-mechanical properties. For the first time, strong relationships between lignin structures and epoxy properties could be demonstrated. The suggested approach provides unprecedented possibilities to tune network structure and properties of thermosets based on real lignin fractions, rather than model compounds.

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Chemicals from Lignin by Catalytic Fast Pyrolysis, from Product Control to Reaction Mechanism

Cited by 25 publications

References 17 publications

Optimization of the Reaction Conditions for Catalytic Fast Pyrolysis of Pretreated Lignin over Zeolite for the Production of Phenol

Optimization of the Reaction Conditions for Catalytic Fast Pyrolysis of Pretreated Lignin over Zeolite for the Production of Phenol

Understanding the mechanism of catalytic fast pyrolysis by unveiling reactive intermediates in heterogeneous catalysis

Tunable Thermosetting Epoxies Based on Fractionated and Well-Characterized Lignins

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