Radicals in flames

If indeed S02 and S03 are effective in reducing the superequilibrium concentration of radicals in flames, sulfur compounds must play a role in NO formation from atmospheric nitrogen in flame systems. Since S02 and S03 form no matter what type of sulfur compound is added to combustion systems, these species should reduce the oxygen atom concentration and hence should inhibit NO formation. Wendt and Ekmann [46] have reported flame data that appear to substantiate this conclusion. 

Barnes ct al. (61a) have detected ground state CH radicals in flame at atmospheric pressure by measuring the CH(/12A - A 2FI) fluorescence intensities excited by a tunable dye laser at 4315 A. 

Laser-Induced Fluorescence Spectroscopy Applied to the Hydroxyl Radical in Flames... 

Laser induced fluorescence is particularly well suited to combustion chemistry, as a sensitive "in-situ" probe for free radicals in flames or under more controlled conditions in laboratory flash photolysis, discharge flow tube, or shock tube experiments. Using laser-saturation fluorescence previous studies from this laboratory (J ) have shown that C2(a3n ) is present in high concentrations in the hot region of an oxy-acetylene flame. C2(a-,n and X1 ) reacts with 0 .(2,3 4) One of the products of this reaction (and/or the reaction of C2H+02) is CC0.(2) In the present study, we report C20()rn.-f, i 7 fluorescence excitation spectra, A"3 , lifetimes and quenching rate constants, and... 

The OH, together with H and O, are some of the most important free radicals in flame combustion pro-... 

K.H. Becker, D. Haaks, T. Taitarczyk, Measurements of C2-radicals in flames with atunable dye lasers. Z. Naturforsch. A 29, 829 (1974)... 

In Germany, Dr. H. Gg. Wagner and his associates have carried out studies of flame structure and free radicals in flames at the Institut fiir Physikalische Chemie at the Universitat Gottingen directed by Prof. Wilhelm Jost. 

This reaction AHlgg = —203.1 kJ) is very fast and therefore one of the main sinks of CH3 radicals in flame propagation in addition to CH3 recombination and combination with H atoms. Consequently, flame propagation is rather sensitive to the rate coefficients of this step (Fig. 4). Though this is a radical-radical reaction, there is a considerable amount of experimental information available in the literature, enabling a relatively safe recommendation (Fig. 32). 

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