La formation de la plupart des composes aromatiques produits lors de la pyrolyse du phenol, ne fait pas intervenir le carbone porteur de la fonction hydroxyle

Cypres, René; Bettens, Bernard

doi:10.1016/0040-4020(75)80046-9

Cited by 55 publications

(15 citation statements)

References 6 publications

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“…It is suggested that cyclopentadiene (CPD) can be a precursor for an additional PAH formation route [136]. Cyclopentadiene is formed via primary reactions of phenols (therefore lignin compounds), in which CO is eliminated from the initial chemical structures in wood, such that CPD is formed, as well as its methyl derivatives [139][140][141]. Further pyrolysis of CPD then leads to the formation of benzene, toluene, indene and naphtalene [142][143][144][145].…”

Section: Theory Of Soot Formation and Its Modelingmentioning

confidence: 99%

Numerical models for thermochemical degradation of thermally thick woody biomass, and their application in domestic wood heating appliances and grate furnaces

Haberle

Skreiberg

Łazar

et al. 2017

Progress in Energy and Combustion Science

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This paper reviews the current state of the art of numerical models used for thermochemical degradation and combustion of thermally thick woody biomass particles. The focus is on the theory of drying, devolatilization and char conversion with respect to their implementation in numerical simulation tools. An introduction to wood chemistry, as well as the physical characteristics of wood, is also given in order to facilitate the discussion of simplifying assumptions in current models. Current research on single, densified or non-compressed, wood particle modeling is presented, and modeling approaches are compared. The different modeling approaches are categorized by the dimensionality of the model (1D, 2D or 3D), and the one-dimensional models are separated into mesh-based and interface-based models. Additionally, the applicability of the models for wood stoves is discussed, and an overview of the existing literature on numerical simulations of small-scale wood stoves and domestic boilers is given. Furthermore, current bed modeling approaches in large-scale grate furnaces are presented and compared against single particle models.

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Section: Theory Of Soot Formation and Its Modelingmentioning

confidence: 99%

Numerical models for thermochemical degradation of thermally thick woody biomass, and their application in domestic wood heating appliances and grate furnaces

Haberle

Skreiberg

Łazar

et al. 2017

Progress in Energy and Combustion Science

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“…[1] DF formation in the homogeneous gas-phase pyrolysis and slow combustion of phenol has been ascribed to the dimerisation of two phenoxy radicals as the first step. [2,3] More recent kinetic and product studies [4,5] showed that DF formation from two phenoxy radicals can occur with an overall rate constant of 10 8  -1 s -1 and above, not so much less than k for the first step, which is approximately 10 10  -1 s -1 . A simple rationale is given in Scheme 1.…”

Section: Introductionmentioning

confidence: 97%

Products, Rates, and Mechanism of the Gas-Phase Condensation of Phenoxy Radicals between 500-840 K

Wiater¹,

Born

Louw

2000

Eur. J. Org. Chem.

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Phenols are demonstrated precursors of “dioxins” ‐ polychlorinated dibenzo‐p‐dioxins (DDs) and dibenzofurans (DFs) ‐ in thermal processes, especially incineration. Heterogeneous catalysis, depending on conditions, can play an important role, but mere gas‐phase combination of phenolic entities to ultimately DD and/or DF is always possible. The present paper addresses the fundamental role of phenol itself. Phenol has long been known to give DF upon pyrolysis and in similar thermal reactions. In the liquid phase under oxidative conditions it yields five condensation products (A‐E); this clearly occurs through the dimerization of two phenoxy (PhO) radicals, followed by enolisation/rearomatisation. Our study shows that in the gas phase, at the lower T end, such dimers are also formed, but still with very little DF. That DF, indeed, is almost the only condensation product at elevated temperatures is substantiated by thermochemical‐kinetic analysis (favouring the pathway of ortho‐C/ortho‐C combination of two PhO radicals), as well as by results obtained with two plausible intermediates, viz. 2,2′‐dihydroxybiphenyl (A) and 2‐phenoxyphenol (C). Mechanisms for the requisite enolisation and dehydration steps leading to DF are discussed.

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“…A number of researchers have investigated the pyrolysis of CPD and shown the importance of cyclopentadienic intermediates in the formation of the initial aromatics. − Several recent continuous flow reactor experiments have investigated the product distribution obtained in the thermal decomposition of CPD. Butler and Glassman measured a wide range of products including expected intermediates such as dihydronaphthalenes and methylcyclopentadienyls in atmospheric pressure experiments between 1000 and 1200 K using highly diluted CPD/nitrogen mixtures.…”

Section: Introductionmentioning

confidence: 99%

“…Ethene, alongside propene, is one of the major products in steam cracking, and CPD is easily formed as intermediate species (e.g., through the reactions of allyl + ethene ,, and allyl + ethyne), followed by subsequent H losses. High CPD formation rates are also to be expected if renewable feedstock sources containing large amounts of oxygenates are used, because molecules such as phenol, ,, anisole, and 2,5-dimethylfuran , are well-known precursors of CPD or CPDyl radicals.…”

Section: Introductionmentioning

confidence: 99%

Detailed Experimental and Kinetic Modeling Study of Cyclopentadiene Pyrolysis in the Presence of Ethene

et al. 2018

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A combined experimental and kinetic modeling study is presented to improve the understanding of the formation of polycyclic aromatic hydrocarbons at pyrolysis conditions. The copyrolysis of cyclopentadiene (CPD) and ethene was studied in a continuous flow tubular reactor at a pressure of 0.17 MPa and a dilution of 1 mol CPD/1 mol ethene/10 mol N2. The temperature was varied from 873 to 1163 K, resulting in cyclopentadiene conversions between 1 and 92%. Using an automated reaction network generator, RMG, we present an elementary step kinetic model for CPD pyrolysis that accurately predicts the initial formation of aromatic products. The model is able to reproduce the product yields measured during the pyrolysis of pure cyclopentadiene and the copyrolysis of cyclopentadiene and ethene. The addition of ethene as coreactant increases the benzene and toluene selectivity. In the absence of ethene, benzene formation is initiated by addition of a cyclopentadienyl radical to cyclopentadiene, following a complicated series of isomerizations and loss of a butadienyl radical. In the presence of ethene, the main pathway for the formation of benzene + CH3 shifts to ethene + cyclopentadiene. Toluene formation is initiated by vinyl radical addition to cyclopentadiene. Without the addition of ethene, vinyl radicals are mainly formed by hydrogen radical addition to ethyne. When ethene is added as coreactant, vinyl radical production happens via hydrogen abstraction from ethene.

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La formation de la plupart des composes aromatiques produits lors de la pyrolyse du phenol, ne fait pas intervenir le carbone porteur de la fonction hydroxyle

Cited by 55 publications

References 6 publications

Numerical models for thermochemical degradation of thermally thick woody biomass, and their application in domestic wood heating appliances and grate furnaces

Numerical models for thermochemical degradation of thermally thick woody biomass, and their application in domestic wood heating appliances and grate furnaces

Products, Rates, and Mechanism of the Gas-Phase Condensation of Phenoxy Radicals between 500-840 K

Detailed Experimental and Kinetic Modeling Study of Cyclopentadiene Pyrolysis in the Presence of Ethene

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