Ab initio and kinetic modeling studies of formic acid oxidation

Marshall, Paul; Glarborg, Peter

doi:10.1016/j.proci.2014.05.091

Cited by 46 publications

(77 citation statements)

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“…26 All HCO profiles from glyoxal decomposition behind shock waves could be very well-simulated, both in terms of absolute HCO concentrations and signal shapes, using the glyoxal decomposition mechanism adopted from Colberg and Friedrichs 2 with branching fractions taken from Friedrichs et al 19 The established glyoxal pyrolysis mechanism was able to predict the measured HCO concentration−time profiles of this work without any modifications. Moreover, by adding oxygen to the reaction mixtures, the rate constant for the reaction HCO + O 2 could be measured at temperatures 1285 K ≤ T ≤ 1705 K, hence significantly extending the range of direct measurements toward higher temperatures.…”

Section: ■ Conclusionmentioning

confidence: 72%

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: ■ Conclusionmentioning

confidence: 72%

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

et al. 2015

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“…Since glyoxal and formic acid are important intermediates in acetylene oxidation under the present conditions, the reaction subsets for these species become important. Both subsets were drawn from recent work by the authors; for glyoxal oxidation from Fassheber et al and for formic acid from Marshall and Glarborg . Experimental data for validation of oxidation mechanisms for glyoxal and formic acid are very limited, and more work on these subset are desirable.…”

Section: Detailed Kinetic Modelmentioning

confidence: 99%

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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“…Additionally, as indicated in the equations above, for each form there are two possible channels of the H-abstraction: an acid (a) or formyl (b). [18,[21][22][23][24][25][26][27][28] In some of these works a catalytic effect of a single water molecule on the gas phase reaction thermodynamics was taken into account. [20] Since this process is of great importance in atmospheric chemistry, there are a number of works investigating this reaction in the gas phase.…”

Section: Resultsmentioning

confidence: 99%

The Mechanism of Oxidation of Formic Acid in Acidic Solutions on Boron‐Doped Diamond Electrodes: A Quantum Chemical Study

et al. 2019

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The oxidation of formic acid (syn-FA and anti-FA forms) by hydroxyl radicals generated on the boron-doped diamond anode in acidic aqueous solution is examined by means of quantum chemical calculations under the assumption that the reaction proceeds according to the outer sphere mechanism, without adsorption of reactants on the electrode. A number of possible reactive complexes [FA ··· HO] and product complexes [COOH ··· H 2 O] formed in solution, as well as the corresponding transition-state structures, were optimized at the MP2/aug-cc-pVTZ theory level, followed by single-point CCSD(T) calcula-tions. It is shown that in aqueous solution the formyl hydrogen abstraction is energetically favored and associated with the effective barriers ΔH b of 0.1-0.2 eV, which are about two times lower than that for carboxylic hydrogen abstraction. The overall reaction is highly exothermic (ΔH of about À 5.8 eV) and expected to be very fast. The results confirm the validity of our hypothesis that the electrochemical incineration of formic acid may occur in solution according to the outer sphere mechanism.[a] Dr. A. Ignaczak, M. Adamiak

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Ab initio and kinetic modeling studies of formic acid oxidation

Cited by 46 publications

References 60 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

The Mechanism of Oxidation of Formic Acid in Acidic Solutions on Boron‐Doped Diamond Electrodes: A Quantum Chemical Study

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Ab initio and kinetic modeling studies of formic acid oxidation

Cited by 46 publications

References 60 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

The Mechanism of Oxidation of Formic Acid in Acidic Solutions on Boron‐Doped Diamond Electrodes: A Quantum Chemical Study

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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