Pulse radiolysis study of concentrated phosphoric acid solutions

Abstract

In the pulse radiolysis of concentrated phosphoric acid solutions, in the direct action on radiation on phosphoric acid gives rise to the phosphate radical. The yields of the phosphate radical and the hydroxyl radical are proportional, respectively, to the electron fractions of phosphoric acid and water, and can be quantified as G(˙OH + H₂PO^˙₄)= 0.30f_w+ 0.33f_sµmol J^–1. The forward and reverse rate constants of the equilibrium ˙OH + H₃PO₄⇄ H₂O + H₂PO^˙₄ were evaluated as 4.2 × 10⁴ and 2.5 × 10³ dm³ mol^–1 s^–1 respectively, from which E⁰(H₂PO^˙₄, H⁺/H₃PO₄)= 2.65 V was derived. The decay kinetics and the reactions of the phosphate radical have also been studied.