2597-43-5Relevant articles and documents
Addition of Water to Premixed Laminar Methanol-Air Flames: Experimental and Computational Results
Olsson, Jim O.,Karlsson, Lennart S.,Andersson, Lars L.
, p. 1458 - 1464 (1986)
Premixed laminar methanol-air flames at 100 torr were studied by experiment and computation.The composition CH3OH/O2/N2/Ar (12.3 percent /18.4 percent /65.3 percent /4.0 percent) corresponds to a stoichiometric composition.The effect of water addition was studied in stoichiometric flames containing about 2.3 mol percent water and 63 mol percent nitrogen but with methanol, oxygen, and argon concentrations unchanged.The amount of water added corresponded to 10 wt percent of the liquid phase.Species profiles were measured by using a modulated molecular beam mass spectrometer.They changed in an insignificant way when water was added.Detailed models for methanol-air combustion, including chemical kinetics and molecular diffusion, were used to compute the flame structure.The base mechanism used was a subunit of the mechanism developed by Westbrook, Dryer, and Schugh.Computations were also made with a mechanism developed by Warnatz.Water addition did not affect the computational concentration profiles significantly.Sensitivity analysis indicated the importance of HCO and CH2OH consumption reactions.Comparisons of experimental and computed concentration profiles supported a high value of the rate constant for the HCO decomposition reaction.This value, about a factor of 5 higher than the one used in the base mechanism, was in agreement with the value recommended by Warnatz.
High-temperature shock tube study of the reactions CH3 + OH → products and CH3OH + Ar → products
Vasudevan, Venkatesh,Cook, Robert D.,Hanson, Ronald K.,Bowman, Craig T.,Golden, David M.
, p. 488 - 495 (2008/12/21)
The reaction between methyl and hydroxyl radicals has been studied in reflected shock wave experiments using narrow-linewidth OH laser absorption. OH radicals were generated by the rapid thermal decomposition of tert-butyl hydroperoxide. Two different species were used as CH3 radical precursors, azomethane and methyl iodide. The overall rate coefficient of the CH3 + OH reaction was determined in the temperature range 1081-1426 K under conditions of chemical isolation. The experimental data are in good agreement with a recent theoretical study of the reaction. The decomposition of methanol to methyl and OH radicals was also investigated behind reflected shock waves. The current measurements are in good agreement with a recent experimental study and a master equation simulation.
Laboratory and theoretical study of the oxy radicals in the OH- and Cl-initiated oxidation of ethene
Orlando, John J.,Tyndall, Geoffrey S.,Bilde, Merete,Ferronato, Corinne,Wallington, Timothy J.,Vereecken, Luc,Peeters, Jozef
, p. 8116 - 8123 (2007/10/03)
The products of the OH-initiated oxidation mechanism of ethene have been studied as a function of temperature (between 250 and 325 K) in an environmental chamber, using Fourier transform infrared spectroscopy for end product analysis. The oxidation proceeds via formation of a peroxy radical, HOCH2CH2O2. Reaction of this peroxy radical with NO is exothermic and produces chemically activated HOCH2CH2O radicals, of which about 25% decompose to CH2OH and CH2O on a time scale that is rapid compared to collisions, independent of temperature. The remainder of the HOCH2CH2O radicals are thermalized and undergo competition between decomposition, HOCH2CH2O → CH2OH + CH2O (6), and reaction with O2, HOCH2CH2O + O2 → HOCH2-CHO + HO2 (7). The rate constant ratio, k6/k7, for the thermalized radicals was found to be (2.0 ± 0.2) × 1025 exp[-(4200 ± 600)/T] molecule cm-3 over the temperature range 250-325 K. With the assumption of an activation energy of 1-2 kcal mol-1 for reaction 7, the barrier to decomposition of the HOCH2CH2O radical is found to be 10-11 kcal mol-1. A study of the Cl-atom-initiated oxidation of ethene was also carried out; the main product observed under conditions relevant to the atmosphere was chloroacetaldehyde, ClCH2CHO Theoretical studies of the thermal and "prompt" decomposition of the oxy radicals were based on a recent ab initio characterization that highlighted the role of intramolecular H bonding in HOCH2CH2O. Thermal decomposition is described by transition state and the Troe theories. To quantify the prompt decomposition of chemically activated nascent oxy radicals, the energy partitioning in the initially formed radicals was described by separate statistical ensemble theory, and the fraction of activated radicals dissociating before collisional stabilization was obtained by master equation analysis using RRKM theory. The barrier to HOCH2CH2O decomposition is inferred independently as being 10-11 kcal mol-1, by matching both of the theoretical HOCH2CH2O decomposition rates at 298 K with the experimental results. The data are discussed in terms of the atmospheric fate of ethene.
