Pulse radiolysis studies on .OH radical induced reactions with substituted iodobenzenes in aqueous solutions

Abstract

The transient optical absorption band formed on pulse radiolysis of N 2O saturated neutral aqueous solution of substituted iodobenzenes (C 6H 4XI, X = H, Br, CH 3, CF 3) has been assigned to hydroxy cyclohexadienyl radical, which absorbs in the region of 320–325 nm. In acidic solutions, the hydroxyl radicals react to form two transient optical absorption bands ( λ max = 310–320, 640–650 nm). The bands are assigned to solute radical cation formed on H +-catalyzed dehydration of OH-adduct. SO 4 .−, specific one-electron oxidant, is found to react with substituted iodobenzenes and form transient optical absorption bands, similar to those formed on reaction of .OH radicals in acidic solutions and are assigned to solute radical cations.