Investigation into reaction of hydroxyl radical with oxalate-ion in acid aqueous solution by pulse radiolysis

Reaction of .OH radical with oxalate-ion in acid aqueous solution was studied by the pulse radiolysis method. The solutions studied after applying an accelerated electron pulse are characterized by optical absorption in UV range induced by formation of .OH radicals and radical products of their interaction with oxalate-ion. Computer simulation of the process was made to describe oxidation of the oxalate-ions. The rate constant of the reaction yielding radical HOOC-COO. (λmax=250 nm, ε=1800 l mol-1 cm-1) is (5.0±0.5)x107 l mol-1 s-1. During interaction with hydrogen ion (k=1.1x107 l mol-1 s-1) radical HOOC-COO. is transformed into a radical of unstated nature, which is conditionally designated as H+(HOOC-COO). (λmax=260 nm, ε=4000 l mol-1 cm-1)