Alkali-metal compounds in oxygen-rich flames. A reinterpretation of experimental results

Abstract

Results of early experiments on alkali metals in premixed oxygen-rich H₂/O₂/N₂ flames are re-examined in the light of subsequent work. It is suggested that these results may be satisfactorily interpreted in terms of reactions of free atoms and hydroxides alone, without recourse to postulating the presence of superoxides. The interpretation offered removes a gross discrepancy between reported values of rate coefficients for production of superoxides. Both the flame results and those of recent independent experiments on superoxide formation are consistent with bond energies for Na—O₂ and K—O₂ of 170 ± 25 and 170 ± 30 kJ mol^–1, respectively.