Ultraviolet spectrum and reaction kinetics of the formyl radical

Hochanadel, C. J.; Sworski, Thomas J.; Ogren, Paul J.

doi:10.1021/j100440a001

Cited by 78 publications

(40 citation statements)

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“…In the data processing, it was found that no satisfactory fits could be achieved without adjusting the cross-section of HCO radical at 230 nm and the rate constants of the reaction of formyl and methyl radicals (reaction (3) was reduced to ca. factor of 2 to 3 lower than the evaluated literature value (2 · 10 À10 cm 3 molecule À1 s À1 [36]), and the absorption cross-section of HCO radical at 230 nm increased from 3.5 · 10 À18 cm 2 (as reported by Hochandanadel et al [27]) to (7-9) · 10 À18 cm 2 . These observations were the reason to perform additional direct measurements of the absorption cross-sections of HCO radical as well as the rate constants of reactions (2) and (3).…”

Section: Resultsmentioning

confidence: 47%

“…Minor channel (4b) produces methane and carbon monoxide, which do not lead to any kinetic interference under the experimental conditions of the current study. The kinetics of formyl radical decay was monitored by absorption in the UV (at 230 nm) [27] as well as at 614.6 nm (with FWHM = 1.0 nm). In the one pass arrangement, an Xe arc lamp (75 W, Oriel Instruments) was used as a monitoring light source.…”

Section: Methodsmentioning

confidence: 99%

“…In the course of the current study, it was found that the UV absorption cross-sections [27] of formyl radical, the rate constant for the HCO self-reaction (2) as well as the reaction of HCO with methyl radical (3) should be revised:…”

Section: Introductionmentioning

confidence: 99%

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Elementary reactions of formyl (HCO) radical studied by laser photolysis—transient absorption spectroscopy

Krasnoperov

Чесноков

Stark

et al. 2005

Proceedings of the Combustion Institute

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Section: Resultsmentioning

confidence: 47%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Elementary reactions of formyl (HCO) radical studied by laser photolysis—transient absorption spectroscopy

Krasnoperov

Чесноков

Stark

et al. 2005

Proceedings of the Combustion Institute

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“…CO þ H J(HCO) = 6.9 Â 10 À10 , 6.0 Â 10 À8 König et al [1984], Hochanadel et al [1980], DeMore et al [1992DeMore et al [ , 1990DeMore et al [ , 1987DeMore et al [ , 1985 DeMore et al [1997] process is very efficient and occurs all the way down to the surface. Mercapto radical quickly reacts with O 3 to form HSO (R43), which upon reaction with O 2 forms SO 2 (R50).…”

Section: Tsang and Hampsonmentioning

confidence: 99%

Chemical markers of possible hot spots on Mars

2003

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Although there is no evidence of active volcanism on Mars today, “localized” outgassing sources, the hot spots, may not be ruled out. If outgassing does occur somewhere on Mars, water, carbon dioxide, sulfur species, methane, and to a lesser extent, halogens would be the likely molecules of outgassing, based on terrestrial analogs. The sulfur species, methane, and halogens have not been detected in the Martian atmosphere, but the observations were averaged over large areas, which could result in substantial dilution in abundances. If the interpretation of certain Mars Global Surveyor images indicating recent ground water seepage and surface runoff [Malin and Edgett, 2000] is correct, it may imply that Mars could still be active internally in some places from time to time, and outgassing of the abovementioned species may occur with or without the water seepage. Moreover, if the tentative detection of formaldehyde (CH2O) in the equatorial region of Mars [Korablev et al., 1993] is confirmed by future observations, it would imply at least local outgassing of methane, whose oxidation results in the formation of CH2O. Considering the possibility of outgassing from some localized hot spots, we have developed a one‐dimensional photochemical model that includes methane (CH4), sulfur dioxide (SO2), and hydrogen sulfide (H2S), starting with their current “global average” upper limits of 0.02, 0.1, and 0.1 ppm at the surface, respectively, and then progressively increasing their abundances above possible hot spots. We find that the introduction of methane into the Martian atmosphere results in the formation of mainly formaldehyde, methyl alcohol (CH3OH), and ethane (C2H6), whereas the introduction of the sulfur species produces mainly sulfur monoxide (SO) and sulfuric acid (H2SO4). The effect of outgassed halogens on the Martian atmosphere is found to be negligible. Depending upon the flux of outgassed molecules from possible hot spots, some of these species and the resulting new molecules may be detectable locally, either by remote sensing or in situ measurements.

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“…3 and 4 were not adopted in this study even though the reported rate measurements [3, 4] appear to have smaller estimated uncertainties than the previous measurements [57, 58]. Instead, we again applied a weighted least squares fitting to all experimental data available in the literature for k 24 [3,22, 57,[60][61][62][63][64][65][66][67][68][69][70][71][72][73], to yield a new rate correlation, [57] within 30%, and is about 2~3 times higher than the correlation recommended by Friedrichs 33 et al [3]. Over 500-1300 K where the rate coefficient of (R24) was measured by Friedrichs et al…”

Section: Hco + M = H + Co + M (R24) and Hco + O 2 = Ho 2 + Co (R25)mentioning

confidence: 99%

Chemical Kinetics in Support of Syngas Turbine Combustion

Dryer¹

2007

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Executive SummaryThis document is the final report on an overall program formulated to extend our prior work in developing and validating kinetic models for the CO/hydrogen/oxygen reaction by carefully analyzing the individual and interactive behavior of specific elementary and subsets of elementary reactions at conditions of interest to syngas combustion in gas turbines. A summary of the tasks performed under this work are: 1. Determine experimentally the third body efficiencies in H+O 2 +M = HO 2 +M (R1) for CO 2 Results are summarized in this document and its appendices. Three archival papers which contain a majority of the research results have appeared. Those results not published elsewhere are highlighted here, and will appear as part of future publications. Portions of the work appearing in the above publications were also supported in part by the Department of Energy under Grant No. DE-FG02-86ER-13503.As a result of and during the research under the present contract, we became aware of other reported results that revealed substantial differences between experimental characterizations of ignition delays for syngas mixtures and ignition delay predictions based upon homogenous kinetic modeling. We adjusted emphasis of Task 2 to understand the source of these noted disparities because of their key importance to developing lean premixed combustion technologies of syngas turbine applications. In performing Task 3, we also suggest for the first time the very significant effect that metal carbonyls may have on syngas combustion properties. This work is fully detailed in Appendix C. The work on metal carbonyl effects is entirely computational in nature. Pursuit of experimental verification of these interactions was beyond the scope of the present work.3 Results over this Progress Period ApproachThe present research further extended our prior work in developing and validating kinetic models for the CO/hydrogen/oxygen principally studied under Department of Energy Grant No. DE-FG02-86ER-13503, by providing additional experimental data using a Variable Pressure Flow Reactor (VPFR) on the collisional efficiencies of water and carbon dioxide in the reaction H+O 2 +M = HO 2 + M (R1) by carefully analyzing the individual and interactive behavior of specific elementary and subsets of elementary reactions at the conditions of interest, and by extending computational model comparisons with data obtained in this program and those appearing in the literature since 2004 to further test and refine the model at conditions relevant to gas turbine applications. Additionally, syngas contaminant species such as small hydrocarbons (e.g., methane) and other combustion gas components (e.g. NO x ) have been identified and it is suspected that these contaminants may affect syngas chemistry in gas turbine applications, particularly in mixing regions of entering fuel and air. These contaminants can have significant influence on some of the kinetic behavior. The initial research plan was to investigate only the effects of small local amo...

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Ultraviolet spectrum and reaction kinetics of the formyl radical

Cited by 78 publications

References 4 publications

Elementary reactions of formyl (HCO) radical studied by laser photolysis—transient absorption spectroscopy

Elementary reactions of formyl (HCO) radical studied by laser photolysis—transient absorption spectroscopy

Chemical markers of possible hot spots on Mars

Chemical Kinetics in Support of Syngas Turbine Combustion

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