Rate coefficient for the reaction H+O sub 2 r arrow OH+O: Results at high temperatures, 2000 to 5300 K

Journal Article · Wed Jan 15 04:00:00 EST 1992 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.462194· OSTI ID:5523616

Du, H; Hessler, J P ^[1]

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1. Gas Phase Chemical Dynamics Group, Chemistry Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 (United States)

The tunable-laser flash-absorption technique has been used to study the high-temperature behavior of the reaction H+O{sub 2}{r arrow}OH+O by monitoring the absorption of the hydroxyl radical. Sensitivity analysis of a detailed reaction mechanism shows that for fuel rich mixtures only two reactions are sensitive when hydroxyl is monitored: H{sub 2}+M{r arrow}2H+M and H+O{sub 2}{r arrow}OH+O. Rate coefficients for these reactions have been determined by least-squares analysis of measured absorption profiles. For the rate of dissociation of H{sub 2} in krypton we obtain {ital k}{sub 1}({ital T})=(8.86{plus minus}0.88){times}10{sup {minus}10} exp({minus}48321/{ital T}(K)) cm{sup 3} s{sup {minus}1} from 3450 to 5300 K. For the H+O{sub 2} reaction we combined our results with previous low temperature measurements and recommend {ital k}{sub 2}({ital T})=(1.62{plus minus}0.12){times}10{sup {minus}10} exp({minus}(7474{plus minus}122)/{ital T}(K)) cm{sup 3} s{sup {minus}1} from 960 to 5300 K. The uncertainties are at the 95% confidence level. Measured cross sections for rotational and vibrational energy transfer in O{sub 2} and OH have been used to show that relaxation effects do not influence the results. We compare our results to recent trajectory calculations. In addition, we calculate the rate of the reverse reaction, OH+O{r arrow}H+O{sub 2}, and compare it to trajectory and statistical adiabatic channel calculations. Finally, we point out that the first excited surface of the hydroperoxyl radical, {sup 2}{ital A}{prime}, which correlates with H({sup 2}{ital S})+O{sub 2}({sup 1}{Delta}{sub {ital g}}), may be needed to explain very high temperature results.

• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5523616
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 96:2; ISSN JCPSA; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
664300 -- Atomic & Molecular Physics-- Collision Phenomena-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DISSOCIATION
ELEMENTS
FLASH HEATING
FLUIDS
GASES
HEATING
HYDROGEN
HYDROGEN COMPOUNDS
HYDROXIDES
KINETICS
KRYPTON
LASERS
LEAST SQUARE FIT
MAXIMUM-LIKELIHOOD FIT
MONITORING
NONMETALS
NUMERICAL SOLUTION
OXYGEN
OXYGEN COMPOUNDS
RARE GASES
REACTION KINETICS
SENSITIVITY ANALYSIS
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
TEMPERATURE RANGE OVER 4000 K
TUNING