Radical Chemistry in the Thermal Decomposition of Anisole and Deuterated Anisoles: An Investigation of Aromatic Growth

Scheer, Adam M.; Mukarakate, Calvin; Robichaud, David J.; Ellison, G. Barney; Nimlos, Mark R.

doi:10.1021/jp102046p

Cited by 101 publications

(137 citation statements)

References 91 publications

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“…It can thus be concluded that there was no degradation of the anisole during the experiments. Further detailed discussion about the anisole thermal decomposition and its initial pyrolysis can be found in [24], [25].…”

Section: Calibration Of the Single Excitation Two-colour Detection Tementioning

confidence: 99%

Temperature measurements in a rapid compression machine using anisole planar laser-induced fluorescence

Tran¹,

Guibert

Morin

et al. 2015

Combustion and Flame

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, et al.. Temperature measurements in a rapid compression machine using anisole planar laser-induced fluorescence. Combustion and Flame, Elsevier, 2015, 162, pp.3960 -3970. <10.1016/j.combustflame.2015 AbstractAdvanced combustion processes induced by self-ignition mechanisms in piston engines, such as Homogeneous Charge Compression Ignition (HCCI), especially need an accurate spatio-temporal temperature information because their phenomenology therefore their performances highly depend on the thermal conditions. The objective of this study is to measure the temperature distribution inside a rapid compression machine (RCM) using anisole planar laser induced fluroescence. The present paper gives a new insight into the interpretation of RCM autoignition data. It also brings useful information for kinetics-related combustion research and combustion modeling. The anisole planar laser-induced fluorescence (PLIF) technique is applied, in order to observe the formation and the evolution of temperature heterogeneities in the combustion chamber prior to the autoignition process. Anisole is used as a novel tracer species, and the fluorescence signal's dependence on parameters, such as temperature, pressure and bath gas composition, is quantified in a high-pressure, high-temperature facility. Calibration of the fluorescence signal is defined under RCM-related temperature and pressure conditions and a protocol is proposed for postprocessing of the PLIF image sequences, allowing the quantitative field temperatures to be determined at successive instants following compression. In order to gain a better understanding of the mixture process, Particle Image Velocimetry (PIV) measurements are analysed under the same conditions. The correlation between thermal and aerodynamic phenomena is determined. The temperature field is found to be non-uniform, with hot and cold centre positions resulting from recirculation inside the chamber, combined with heat transfer effects from the chamber wall.

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Section: Calibration Of the Single Excitation Two-colour Detection Tementioning

confidence: 99%

Temperature measurements in a rapid compression machine using anisole planar laser-induced fluorescence

Tran¹,

Guibert

Morin

et al. 2015

Combustion and Flame

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“…All other frequencies remain unchanged. The partition function for a hindered rotation is obtained by first approximating the hindrance potential with a truncated Fourier series, second calculating the averaged reduced moment of inertia for the one-dimensional rotation at the I (2,3) level as defined by East and Radom [19] based on the work of Kilpatrick and Pitzer [20], and third solving the Schroedinger equation numerically using the wave functions of the free rotor as basis functions. The solution is a set of energy eigenvalues, which immediately yields the partition function for this mode as well as derived properties such as the contribution of this mode to the thermodynamic functions enthalpy (H ), entropy (S), and heat capacities (C p ).…”

Section: Pes and Thermochemistry Calculationsmentioning

confidence: 99%

“…Pyrolysis studies on lignin revealed that the initial pyrolysis products are constituted largely of its monomers such as guaiacols, coniferyl alcohol, and so on [1], which upon further decomposition in the gas phase yield phenoxy radicals as intermediates. CO loss from phenoxy radical leads to cyclopentadienyl radical, a precursor to benzene and naphthalene [2,3]. A detailed description of the tar (molecular weight growth species) forming chemistry thus must include a thorough understanding of the unimolecular decomposition of phenoxy radicals.…”

Section: Introductionmentioning

confidence: 99%

A quantitative kinetic analysis of CO elimination from phenoxy radicals

Carstensen

Dean

2011

Int J of Chemical Kinetics

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Phenoxy radicals are expected to play an important role in the thermal decomposition of lignin. At high enough temperatures, the dissociation to cyclopentadienyl radicals plus carbon monoxide dominates over bimolecular channels. While earlier experimental and theoretical studies agree on the mechanism, the experimental data suggest a substantially lower overall barrier than that found in theoretical studies. To address this discrepancy, we performed electronic structure calculations at the CBS-QB3 level of theory and at a modified version of it to construct the relevant portion of the C 6 H 5 O potential energy surface (PES).The new results are in good agreement with previous studies. We then used the molecular information to calculate thermodynamic properties of the reactants and activated complexes, the high-pressure rate constants, and the pressure dependence. Three different methods were employed for the last step: the quantum version of the Rice-Ramsperger-Kassel/modified strong collision theory approach by Dean (J Phys Chem 1985, 89, 4600-4608), the stochastic treatment by Barker (Int J Chem Kinet 2001, 33, 232-245) using the MultiWell package, and the master equation program Unimol by Gilbert and coworkers. Theory of Unimolecular and Recombination Reactions. Oxford, Blackwell Scientific Publications. All methods predict the experimentally determined phenoxy decomposition rate constant to be in the falloff region. This explains the almost 10 kcal mol −1 difference between reported activation energies and calculated barriers. Both the Lin and Lin (J Phys Chem 1986, 90, 425-431) and Frank et al. (Proc Combust Inst 1994, 25, 833-840) data can be reproduced within the assumed uncertainty limits without any adjustments of the PES. We also report on falloff behavior in the CO elimination from methyl-, hydroxy-, and methoxy-substituted phenoxy radicals in the para position and compare it to that of the unsubstituted phenoxy radical.

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“…[3] The oxidation of phenol with dioxygen in the presence of metallic copper resulted in the aromatic ring contraction to afford substituted cyclopentenes. [4] Carbocycle contraction to benzvalene followed by opening of the ring to form benzene was postulated in theoretical studies on the high-temperature intramolecular topomerization of [1,2-13 C 2 ]benzene to [1, [3][4][5][6][7][8][9][10][11][12][13] C 2 ]-and [1,4-13 C 2 ]benzene. [5] In more general terms, the benzene contraction belongs to an exclusive group of reactions where the cleavage of aromatic structures is of fundamental importance.…”

mentioning

confidence: 99%

A Facile Palladium‐Mediated Contraction of Benzene to Cyclopentadiene: Transformations of Palladium(II) p‐Benziporphyrin

2011

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Radical Chemistry in the Thermal Decomposition of Anisole and Deuterated Anisoles: An Investigation of Aromatic Growth

Cited by 101 publications

References 91 publications

Temperature measurements in a rapid compression machine using anisole planar laser-induced fluorescence

Temperature measurements in a rapid compression machine using anisole planar laser-induced fluorescence

A quantitative kinetic analysis of CO elimination from phenoxy radicals

A Facile Palladium‐Mediated Contraction of Benzene to Cyclopentadiene: Transformations of Palladium(II) p‐Benziporphyrin

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