HCO formation in the thermal unimolecular decomposition of glyoxal: rotational and weak collision effects

Friedrichs, Gernot; Colberg, Mark R.; Dammeier, Johannes; Bentz, Tobias; Olzmann, Matthias

doi:10.1039/b809992h

Cited by 21 publications

(38 citation statements)

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“…Thermal dissociation of OCHCHO has been characterized experimentally behind shock waves 18,19 and theoretically. 19,37 It 31 and the reaction OCHCHO → OCHCO + H. There are isomers of OCHCO with bent C−C−O structures, but the most stable isomer has an almost linear C−C−O group.…”

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

“…19,37 It 31 and the reaction OCHCHO → OCHCO + H. There are isomers of OCHCO with bent C−C−O structures, but the most stable isomer has an almost linear C−C−O group. The corresponding bond dissociation enthalpy is 366.2 kJ mol −1 , which corresponds to Δ f H 298°( OCHCO) = −63.8 kJ mol −1 .…”

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

“…The thermodynamic properties for OCHCHO and OCHCO are shown in Table 1, 30,31 whereas Table 2 lists key reactions in the OCHCHO oxidation scheme. 2,19,32,34,35 The full mechanism, including pressure-dependent rate coefficients for many decomposition and recombination reactions, is available as Supporting Information.…”

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

“…A mechanism has been assembled from recent work on the chemistry of glyoxal, 2,19 formic acid, 26 formaldehyde, 27 carbon monoxide, 28 and hydrogen. 29 In the present work, the OCHCHO oxidation subset of the mechanism was updated.…”

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

“…1,2 Moreover, glyoxal is discussed as an important component in tropospheric chemistry. 3,4 Glyoxal can be formed from oxidation of C 2 H 2 at low to medium temperatures, 5−9 as well as in the atmosphere, 10 Previous studies of OCHCHO chemistry include thermal decomposition in static reactors 17 and shock tubes 18,19 as well as low-temperature oxidation 20−22 and determination of explosion limits in static reactors. 23 Also, data on the lowtemperature oxidation of glyoxal by H 2 O 2 24 and NO 2 25 have been reported.…”

Section: ■ Introductionmentioning

confidence: 99%

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Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O₂ and OCHCHO + HO₂

et al. 2015

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A detailed mechanism for the thermal decomposition and oxidation of the flame intermediate glyoxal (OCHCHO) has been assembled from available theoretical and experimental literature data. The modeling capabilities of this extensive mechanism have been tested by simulating experimental HCO profiles measured at intermediate and high temperatures in previous glyoxal photolysis and pyrolysis studies. Additionally, new experiments on glyoxal pyrolysis and oxidation have been performed with glyoxal and glyoxal/oxygen mixtures in Ar behind shock waves at temperatures of 1285−1760 K at two different total density ranges. HCO concentration−time profiles have been detected by frequency modulation spectroscopy at a wavelength of λ = 614.752 nm. The temperature range of available direct rate constant data of the hightemperature key reaction HCO + O 2 → CO + HO 2 has been extended up to 1705 K and confirms a temperature dependence consistent with a dominating direct abstraction channel. Taking into account available literature data obtained at lower temperatures, the following rate constant expression is recommended over the temperature range 295 K < T < 1705 K: k 1 /(cm 3 mol −1 s −1 ) = 6.92 × 10 6 × T 1.90 × exp(+5.73 kJ/mol/RT). At intermediate temperatures, the reaction OCHCHO + HO 2 becomes more important. A detailed reanalysis of previous experimental data as well as more recent theoretical predictions favor the formation of a recombination product in contrast to the formerly assumed dominating and fast OH-forming channel. Modeling results of the present study support the formation of HOCH(OO)CHO and provide a 2 orders of magnitude lower rate constant estimate for the OH channel. Hence, low-temperature generation of chain carriers has to be attributed to secondary reactions of HOCH(OO)CHO.

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Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

Section: ■ Detailed Kinetic Modelmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

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Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O₂ and OCHCHO + HO₂

et al. 2015

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Experimental and Kinetic Modeling Study of C₂H₂ Oxidation at High Pressure

Giménez-López

Rasmussen

Hashemi

et al. 2016

Int J of Chemical Kinetics

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A detailed chemical kinetic model for oxidation of C 2 H 4 in the intermediate temperature range and high pressure has been developed and validated experimentally. New ab initio calculations and RRKM analysis of the important C 2 H 3 + O 2 reaction was was used to obtain rate coefficients over a wide range of conditions (0.003-100 bar, 200-3000 K). The results indicate that at 60 bar vinyl peroxide, rather than CH 2 O and HCO, is the dominant product.The experiments, involving C 2 H 4 /O 2 mixtures diluted in N 2 , were carried out in a high pressure flow reactor at 600-900 K and 60 bar, varying the reaction stoichiometry from very lean to fuel-rich conditions. Model predictions are generally satisfactory. The governing reaction mechanisms are outlined based on calculations with the kinetic model. Under the investigated conditions the oxidation pathways for C 2 H 4 are more complex than those prevailing at higher temperatures and lower pressures. The major differences are the importance of the hydroxyethyl (CH 2 CH 2 OH) and 2-hydroperoxyethyl 1 (CH 2 CH 2 OOH) radicals, formed from addition of OH and HO 2 to C 2 H 4 , and vinyl peroxide, formed from C 2 H 3 + O 2 . Hydroxyethyl is oxidized through the peroxide HOCH 2 CH 2 OO (lean conditions) or through ethenol (low O 2 concentration), while 2-hydroperoxyethyl is converted through oxirane. [2][3][4][5][6][7], shock tubes [8][9][10][11][12] and premixed laminar flames [13][14][15][16][17], covering a wide range of stoichiometries and temperatures. Most of the reported work, however, have been carried out at near atmospheric pressure. A few results are available from flow reactor studies at 5-10 bar [6], but despite their relevance for the chemistry in engines, gas turbines, and gas-to-liquid processes, data at high pressures are limited.The objective of the present study is to obtain experimental results for the oxidation of C 2 H 4 at high pressure (60 bar) as functions of temperature (600-900 K) and stoichiometry (lean to fuel-rich) and analyze them in terms of a detailed chemical kinetic model. The oxidation pathways for C 2 H 4 under these conditions are different from those prevailing at higher temperatures and lower pressures and the results of the current work help to extend the validation range for chemical kinetic modeling of C 2 H 4 oxidation. This paper is part of a series investigating the high-pressure, medium temperature oxidation of simple fuels: previously work has been reported for CO/H 2 , CH 4 , and CH 4 /C 2 H 6 mixtures [18,19]. The present kinetic model draws on this work, as well as recent results in tropospheric chemistry. Furthermore, the important reaction of C 2 H 3 with O 2 was characterized from ab initio calculations over a wide range of pressure and temperature. 3 ExperimentalThe experimental setup is a laboratory-scale high pressure laminar flow reactor designed to approximate plug-flow. The setup is described in detail elsewhere [18] and only a brief description is provided here. The system enables well-defined investigations of...

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Statistical Rate Theory in Combustion: An Operational Approach

Olzmann

2013

Cleaner Combustion

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HCO formation in the thermal unimolecular decomposition of glyoxal: rotational and weak collision effects

Cited by 21 publications

References 49 publications

Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O₂ and OCHCHO + HO₂

Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O₂ and OCHCHO + HO₂

Experimental and Kinetic Modeling Study of C₂H₂ Oxidation at High Pressure

Statistical Rate Theory in Combustion: An Operational Approach

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HCO formation in the thermal unimolecular decomposition of glyoxal: rotational and weak collision effects

Cited by 21 publications

References 49 publications

Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O2 and OCHCHO + HO2

Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O2 and OCHCHO + HO2

Experimental and Kinetic Modeling Study of C2H2 Oxidation at High Pressure

Statistical Rate Theory in Combustion: An Operational Approach

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Product

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Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O₂ and OCHCHO + HO₂

Glyoxal Oxidation Mechanism: Implications for the Reactions HCO + O₂ and OCHCHO + HO₂

Experimental and Kinetic Modeling Study of C₂H₂ Oxidation at High Pressure