Rates of Reaction of Hydroxyalkyl Radicals with Molecular Oxygen

Article abstract of DOI:10.1021/j100370a052

The rate constants for the reactions of a series of hydroxyalkyl radicals with molecular oxygen have been measured at room temperature (296 +/- 4 K) by laser flash photolysis-photoionization mass spectrometry.Measured rate constants are k = (1.17 +/- 0.12) * 1E-11, k = (2.61 +/- 0.41) * 1E-11, k = (1.16 +/- 0.22) * 1E-11, k = 3.82 +/- 0.60) * 1E-12, and k = (3.71 +/- 0.62) * 1E-11, all in units of cm³ molecule^-1 s^-1.These reactions seem to be at high-pressure limits at experimental pressures (1.3-5.5 Torr of He).Although it has been suggested in previous studies that the reaction mechanisms are different between α- and β-hydroxyalkyl radicals (H atom abstractions and recombinations, respectively), the present rates of reaction involving both α- and β-hydroxyalkyl radicals were found to correlate well with the ionization potentials of the radicals.This results suggests that the rate constants for all these reactions are largely controlled by the long-range forces similar to the reactions of alkyl radicals with molecular oxygen.