Reactions of Hydro Peroxide Radicals in Hydrogen Combustion

Abstract

Molecules of H2O2 and H2O are detected in gas phase in deuterium—oxygen flame by their near IR emission spectra in the reactor, which surface was previously treated with atomic hydrogen. It was shown that both the formation of these compounds and the observed decrease in the lower limit of spontaneous ignition of D2 + O2 mix under influence of adsorbed hydrogen atoms are caused by heterogeneous elementary reactions providing chain propagation. The initial stage is the reaction of adsorbed atomic hydrogen with O2 from the gas phase. The emission spectra of hydrogen–oxygen and hydrogen–air flames at 0.1–1 atm exhibit a system of bands between 852 and 880 nm, which are assigned to the H2O2 molecule vibrationally excited into the overtone region. This molecule results from the reaction HO2 + O2. The overtone region also contains bands at 670 and 846 nm, which are assigned to the vibrationally excited HO2 radical. The radical is the product of the reaction between H and O2. The HO2 radicals resulting from H2 or D2 oxidation inhibited by small amounts of propylene are initially in vibrationally excited states.