Dean, A.M., and Kistiakowsky, G.B. (1971)
Oxidation of Carbon Monoxide/Methane Mixtures in Shock Waves
J. Chem. Phys. 1971, 54, 1718.
Abstract
CO/O2/Ar mixtures with mole fractions of 4%/2%/94% and containing 180 or 500 ppm CH4 were investigated in incident shock waves at about 5E+17 particles/cm3 total concentration. The reaction was followed by measuring infrared emissions from CO2 and CO for about 1500 µs particle time over the temperature range 1750-2575 K. The rate of CO2 production initially increased exponentially and then became constant after several percent conversion. The observed [CO2]-time profiles were compared to those calculated by numerical integration on IBM 360/65 computer. It was possible to quantitatively describe the observations in terms of a mechanism with the following main reactions: (31), (99), (38), (-52), (11), (156), (10), and (A) (rate constants are shown below), in addition to several relatively unimportant reactions involving chain carriers CH4 and trace impurities H2 and H2O. Values of k(99) and k(38) were taken from the literature; others were determined by finding the best fit of the calculated [CO2]-time profiles to the experimental ones. Consequently, some change of the individual rate parameter values is possible without losing reasonable agreement with experiments. However, a substantial disagreement between the values of k(-52) and k(156) and literature values is attributed to the earlier workers´ use of only the induction period data. Methane was found to be more effective than either H2 or H2O in promoting the branching chain oxidation of CO. Extending these observations, it is pointed out that extremely small concentrations of organic compounds can strongly influence many features of the CO/O2 system.

REACTION RATE COEFFICIENTS SUGGESTED IN THIS WORK:

GRI-Mech
Number
('-' sign
means
reverse)		 Reaction Rate Coefficient
A T^n exp(-E/RT)		 Temperature
Range
(K)
A
(mol,cm3,s)		 n
(T in K)		 E
(cal/mol)
10 CH3 + O -> H + CH2O 6.02E+13     1750-2575
11 O + CH4 -> OH + CH3 1.57E+14   7950 1750-2575
31 CO + O2 -> O + CO2 1.2E+13   60000 1750-2575
-52 CH4 + M -> H + CH3 + M 1.63E+18   103000 1750-2575
156 CH3 + O2 -> OH + CH2O 3.01E+13   10000 1750-2575
A O + CH2O -> H + CO + OH 6.02E+13     1750-2575