Energized complex quantum Rice-Ramsperger-Kassel analysis on reactions of NH sub 2 with HO sub 2 , O sub 2 , and O atoms

Journal Article · Thu Feb 09 04:00:00 EST 1989 · Journal of Physical Chemistry; (USA)

DOI:https://doi.org/10.1021/j100340a009· OSTI ID:5049809

Bozzelli, J W; Dean, A M ^[1]

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1. Exxon Research and Engineering Co., Annandale, NJ (USA)

The addition reactions of NH{sub 2} with HO{sub 2}, O{sub 2}, and O to form energized adducts have been analyzed as a chemically activated system by using a bimolecular version of the quantum Rice-Ramsperger-Kassel (QRRK) theory for temperatures from 200 to 1900 K and pressures from 0.001 to 10 atm with various bath gases. We predict that essentially 100% of the (NH{sub 2}OOH)* adduct from the NH{sub 2} + HO{sub 2} reaction dissociates to the low-energy exit channel NH{sub 2}O + OH over the above temperature and pressure regimes. Stabilization or isomerization of the complex and subsequent dissociation to NHO + H{sub 2}O does not occur to any significant extent. This result suggests that NH{sub 2} + HO{sub 2} {yields} NH{sub 2}O + OH should be included in kinetic models for ammonia oxidation. Our calculations on the reaction of NH{sub 2} + O{sub 2} {yields} NH{sub 2}O{sub 2} are in agreement with the experimentally observed upper limits obtained in previous studies. We utilize the room-temperature upper limit rate constant data of Michael et al. to calculate an upper limit bond strength for NH{sub 2}-OO of 12.5 kcal/mol. The isomerization barrier height NH{sub 2}O{sub 2} {leftrightarrow} HNOOH in the NH{sub 2} + O{sub 2} reaction is shown to be dominant, below 600 K, for control of the principal reaction channel NH{sub 2}O + O versus NHO + OH. Above this temperature NH{sub 2}O + OH versus HNO + H products calculated from fundamental thermodynamic and kinetic principles are in remarkably good agreement with the experimental results of Dransfield et al. These branching ratios are nearly independent of pressure up to 10 atm but are somewhat dependent on exit channel barriers. Stabilization to NH{sub 2}O is unimportant below 10 atm.

• OSTI ID: 5049809
• Journal Information: Journal of Physical Chemistry; (USA), Journal Name: Journal of Physical Chemistry; (USA) Vol. 93:3; ISSN 0022-3654; ISSN JPCHA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
54 ENVIRONMENTAL SCIENCES
540110
ADDUCTS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
ELEMENTS
HYDROPEROXY RADICALS
INFORMATION
KINETICS
MECHANICS
NITROGEN COMPOUNDS
NONMETALS
NUMERICAL DATA
OXYGEN
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
QUANTUM MECHANICS
RADICALS
REACTION INTERMEDIATES
REACTION KINETICS
THEORETICAL DATA
THERMODYNAMIC PROPERTIES
THERMODYNAMICS