Quantitative Investigation of Free Radicals in Bio‐Oil and their Potential Role in Condensed‐Phase Polymerization

Kim, Kwang Ho; Bai, Xianglan; Cady, Sarah D.; Gable, Preston; Brown, Robert C.

doi:10.1002/cssc.201403275

Cited by 59 publications

(59 citation statements)

References 50 publications

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“…It postulated that these radicals could possibly be oligosaccharides in nature, given the fact that a radical in fifth position in a glucose ring is stabilized by the adjacent alkyl group and oxygen atom. This study provides an evidence for free‐radical generation during homolytic cleavage of glycosidic bonds leading to the formation of stable free‐radicals and decarbonylation of monomeric units which result in the formation of CO (Kim et al, ).…”

Section: Mechanistic and Intrinsic Kinetic Studies Of Biomass Pyrolysismentioning

confidence: 87%

Measuring biomass fast pyrolysis kinetics: State of the art

SriBala

Carstensen

Marin

2018

WIREs Energy & Environment

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Fast pyrolysis of lignocellulosic biomass is considered to be a promising thermochemical route for the production of drop‐in fuels and valuable chemicals. During the past decades, a comprehensive understanding of feedstock structure, fast pyrolysis kinetics, product distribution, and transport effects that govern the process has allowed to design better pyrolysis reactors and/or catalysts. A variety of lignocellulosic biomass feedstocks, like corn stover, pinewood, poplar, and model compounds like glucose, xylan, monolignols have been utilized to study the thermal decomposition at or close to fast pyrolysis conditions. Significant progress has been made in understanding the kinetics by developing unique setups such as drop‐tube, PHASR, and micropyrolyzer reactors in combination with the use of advanced analytical techniques such as comprehensive gas and liquid chromatography (GC, LC) with time‐of‐flight mass spectrometer (TOF‐MS). This has led to initial intrinsic kinetic models for biomass and its main components, namely cellulose, hemicellulose, and lignin, validated using experimental setups where the effects of heat and mass transfer on the performance of the process, expressed using Biot and pyrolysis numbers, are adequately negligible. Yet, not all aspects of fast pyrolysis kinetics of biomass components are equally well understood. The use of time‐resolved or multiplexed experimental techniques can further improve our understanding of reaction intermediates and their corresponding kinetic mechanisms. The novel experimental data combined with first principles based multiscale models can reshape biomass pyrolysis models and transform biomass fast pyrolysis to a more selective and energy efficient process. This article is categorized under: Energy and Climate > Climate and Environment Energy Research & Innovation > Science and Materials Bioenergy > Science and Materials

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Section: Mechanistic and Intrinsic Kinetic Studies Of Biomass Pyrolysismentioning

confidence: 87%

Measuring biomass fast pyrolysis kinetics: State of the art

SriBala

Carstensen

Marin

2018

WIREs Energy & Environment

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“…A recent study by Kim et al showed that the majority of radicals contained in pyrolysis oil from wood are the products of lignin pyrolysis. [22] However, it seems that those radicals are stable and do not influence the stability of the liquid obtained after pyrolysis towards repolymerization, at least on the short term. Catalytic/non-catalytic pyrolysis of lignin comprises a very complex set of reactions due to the wide variety of bonds and monomers in the lignin matrix.…”

Section: Fast Pyrolysis Chemistrymentioning

confidence: 99%

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

Custodis

Hemberger

et al. 2015

Chimia

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Conversion of lignin into renewable and value-added chemicals by thermal processes, especially pyrolysis, receives great attention. The products may serve as feedstock for chemicals and fuels and contribute to the development of a sustainable society. However, the application of lignin conversion is limited by the low selectivity from lignin to the desired products. The opportunities for catalysis to selectively convert lignin into useful chemicals by catalytic fast pyrolysis and our efforts to elucidate the mechanism of lignin pyrolysis are discussed. Possible research directions will be identified.

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“…Free radicals have been detected in various conditions during the pyrolysis of lignin and its model compounds in the gas phase, 11,12 bio-oil 13,14 and biochar media. 16 Kibet et al .…”

Section: Introductionmentioning

confidence: 99%

Radicals from the gas-phase pyrolysis of a lignin model compound: p-coumaryl alcohol

Khachatryan

Baev

et al. 2016

RSC Adv.

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The intermediate radicals produced in the gas-phase pyrolysis of one of the main building blocks of lignin – p-coumaryl alcohol (p-CMA) – were investigated using the low temperature matrix isolation technique interfaced with electron paramagnetic resonance spectroscopy (LTMI-EPR). An anisotropic EPR spectrum characterized by a high g-value (>2.0080) and a relatively low saturation coefficient (∼1.40) throughout the high pyrolytic temperature region (700 to 1000 °C) was observed. Theoretical calculations revealed plausible decomposition pathways for p-CMA comprising highly delocalized aromatic radicals. The results provide evidence for a dominant role of oxygen-centered radicals during the pyrolysis of p-CMA.

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Quantitative Investigation of Free Radicals in Bio‐Oil and their Potential Role in Condensed‐Phase Polymerization

Cited by 59 publications

References 50 publications

Measuring biomass fast pyrolysis kinetics: State of the art

Measuring biomass fast pyrolysis kinetics: State of the art

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

Radicals from the gas-phase pyrolysis of a lignin model compound: p-coumaryl alcohol

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