Kinetics of the NH[sub 2] + NO reaction. Effects of temperature on the total rate constant and the OH/H[sub 2]O branching ratio

Journal Article · Thu Apr 14 04:00:00 EDT 1994 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100066a022· OSTI ID:7165830

Diau, E W; Yu, T; Wagner, M A.G.; Lin, M C ^[1]

---

1. Emory Univ., Atlanta, GA (United States)

The rate constant for the reaction of NH[sub 2] with NO has been measured between 297 and 673 K using the cavity-ring-down technique to monitor the disappearance of the NH[sub 2] radical. The measured bimolecular rate constant can be effectively represented by the expression k[sup II] = (2.2 [+-] 0.7) x 10[sup [minus]12] exp[525 [+-] 80/T] cm[sup 3]/s, which agrees reasonably well with the results of several other recent measurements employing various diagnostic methods. A multichannel RRKM calculation has been carried out to account for the observed negative temperature dependence and the product branching ratio, OH/H[sub 2]O, based on Walch's recent potential energy surface data for various transition states and stable intermediates leading to the formation of the OH and H[sub 2]O products. The predicted temperature dependencies agree reasonably well with experimental observations. We have also performed kinetic modeling using a set of of reactions involving H, NH[sub 3], NH[sub 2], NO, and their anticipated products. The result of the modeling aided by sensitivity analysis suggests that the unknown [open quotes]third channel[close quotes] responsible for the decline of the ([OH] + [H[sub 2]O])/[NH[sub 2]][sub 0] ratio at high temperatures (ref 23) may result from secondary reactions which produce neither OH nor H[sub 2]O. These reactions include NH[sub 2] + H [yields] NH + H[sub 2] and NH[sub 2] + NH[sub 2] [yields] NH + NH[sub 3]. 69 refs., 9 figs., 5 tabs.

• OSTI ID: 7165830
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 98:15; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
54 ENVIRONMENTAL SCIENCES
540120 -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (1990-)
AMMONIA
CHALCOGENIDES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
DATA
EXPERIMENTAL DATA
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
KINETICS
MATHEMATICAL MODELS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN OXIDES
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
RADICALS
REACTION KINETICS
SENSITIVITY ANALYSIS
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 0273-0400 K
TEMPERATURE RANGE 0400-1000 K
THEORETICAL DATA