Pulse-radiolytic investigation of the reduction of titanium(III) ions in aqueous solutions

Abstract

The absorption spectrum and decay kinetics of intermediates formed by the reaction of titanium(III) ions with H atoms, hydrated electrons, and carboxyl radicals have been studied in aqueous solution using the pulse-radiolysis technique. The product of the reaction with H atoms in acid solution is a Ti³⁺–H hydride intermediate which decomposes by a first-order process with a half-life of ca. 3 s. Titanium(II) is formed by reaction with hydrated electrons and ˙CO₂H radicals. The absorption spectrum of titanium(II) and the kinetics of its reactions are reported and discussed. The formation of molecular hydrogen by reaction of Ti²⁺ with water is suppressed by the other solutes in the solutions. Titanium(III) reacts with ˙CO₂H, ˙CH₂CO₂H, and ˙CH(CO₂H)₂ radicals to give titanium–radical complexes.