Measurements were made for the rate constant of OH + CO + He at 293 K, and OD + CO + M (M = He, Ar, N2, air, SF6) at 253−343 K. Results were also obtained for OH + CO in a shock tube at 1400−2600 K using OH and CO absorption. A two-channel RRKM model of these and other representative results was constructed, with five adjustable parameters. A systematic optimization method was then employed to produce the best fit of the data and provide predictive k(T,P,D/H) expressions for other conditions.

Seven mixtures of formaldehyde and oxygen diluted in argon were studied behind reflected shock waves at temperatures from 1340 to 2270 K and pressures from 0.7 to 2.5 atm. Mixture compositions covered a range from pure pyrolysis to lean oxidation at a stoichiometric ratio of 0.17. The progress of reaction was monitored by laser absorption of CO molecules. Experimental rates of CO formation were found to be 80% higher, in the case of pyrolysis, and 30% lower, under lean oxidation, than those predicted by the current reaction model, GRI-Mech 1.2. The collected experimental data were subjected to extensive detailed chemical kinetics analysis, including optimization with the solution mapping technique. The analysis identified a strong correlation between two rate constants. Assuming a recent literature expression for one of them produced k - 1a = 2.66 × 1024 T -2.57e-215/ T cm6 mol-2 s-1 for the reaction H + HCO + M → CH2O + M. A new expression was developed for the reaction HO2 + CH2O → HCO + H2O2, k 6 = 4.11 × 104 T 2.5e-5136/ T cm3 mol-1 s-1, by fitting the present and literature results. With these modifications, the new reaction model provides good agreement with our experimental data and an acceptable agreement with most literature experimental observations.

Nine mixtures of acetylene and oxygen diluted in argon were studied behind reflected shock waves at temperatures of 1150-2132 K and pressures of 0.9-1.9 atm. Initial compositions were varied from very fuel-lean to moderately fuel-rich, covering equivalence ratios of 0.0625-1.66. Two more mixtures with added ethylene were used to boost the sensitivity to reactions of vinyl oxidation. The progress of reaction was monitored by laser absorption of CO molecules. The collected experimental data were subjected to extensive detailed chemical kinetics analysis. The initial kinetic model was assembled based on recent literature data and then optimized using the solution mapping technique. The analysis was extended to include recent experimental observations of Hidaka and co-workers (Combust Flame 1996, 107, 401). The derived model reproduces closely both sets of experimental data, the result obtained by modifying nine rate coefficients and three enthalpies of formation of intermediate species. The identified parameter tradeoffs and justification for the changes are discussed.

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