Rate of CH[sub 4] dissociation over 2800-4300 K: The low-pressure-limit rate constant

Journal Article · Thu Jan 14 04:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100104a024· OSTI ID:6207523

Kiefer, J H; Kumaran, S S ^[1]

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1. Univ. of Illinois, Chicago (United States)

The rate of dissociation of CH[sub 4] dilute in both Kr and Ar has been measured in incident shock waves with the laser-schlieren technique. The measurements cover the very high temperature range 2800-4400 K in 2% CH[sub 4]-Kr, 2% CH[sub 4]-Ar, and 0.5% CH[sub 4]-Kr, with moderate pressures of 230-660 Torr. Density gradient profiles are model-extrapolated some 0.5[mu]s to t = 0 and rate constants evaluated at the vibrationally-relaxed, chemically frozen condition. These rate constants form a quite consistent set (RMS deviations [+-]7%) with no discernible difference between mixtures. Their temperature variation shows definite Arrhenius curvature, but this is in full accord with an adjusted RRKM model of k[sub o] having the known bond energy as the barrier. This model also predicts rates very close to a summary of previous work below 2500K. A modified-Arrhenius fit of these RRKM calculations of the low-pressure-limit rate constant should be accurate ([+-]50%) over 1600-4000 K. 37 refs., 7 figs., 6 tabs.

• OSTI ID: 6207523
• Journal Information: Journal of Physical Chemistry; (United States), Journal Name: Journal of Physical Chemistry; (United States) Vol. 97:2; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
ALKANES
ARGON
ARRHENIUS EQUATION
CHEMICAL REACTION KINETICS
DISPERSIONS
DISSOCIATION
ELEMENTS
EQUATIONS
FLUIDS
GASES
HYDROCARBONS
KINETICS
KRYPTON
LOW PRESSURE
MATHEMATICAL MODELS
METHANE
MIXTURES
NONMETALS
ORGANIC COMPOUNDS
PHOTOGRAPHY
RARE GASES
REACTION KINETICS
SCHLIEREN METHOD
SHOCK WAVES
TEMPERATURE DEPENDENCE
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
TEMPERATURE RANGE OVER 4000 K