High-Temperature Reaction Kinetics of the e_aq^- and HO₂^• Radicals with Iron(II) Ions in Aqueous Solutions

Pulsed electron radiolysis was used to determine the chemical reaction kinetics and Arrhenius parameters for iron(II) reactions in aqueous solutions under irradiation. The second-order Fe²⁺ reactions with the hydrated electron (e_aq^-) and the perhydroxyl radical (HO₂^•), arising from water radiolysis, were measured to high temperatures using custom-built flow-through cells with a multichannel optical detection system. The reaction with the HO₂^• radical was found to proceed via the formation of a metal-ion adduct species, Fe²⁺-HO₂^•. The adduct's molar extinction coefficient and its first-order decay rate coefficients are also reported.