A pulse radiolytic study of aqueous nitroaniline solutions

Abstract

The reactions of hydroxyl radicals, hydrated electrons and hydrogen atoms with nitroaniline in aqueous solution have been studied by means of pulse radiolysis. The following values were obtained for the rate constants: k(OH + nitroaniline) = (1.4 ± 0.2) × 10 10 dm 3 mol -1 s -1, k(e - eq + nitroaniline) = (1.8 ± 0.2) × 10 9 dm 3 mol -1 s -1 and k(H + nitroaniline) = (2.0 ± 0.2) × 10 9 dm 3 mol -1 s -1. It was found that HNO 2 elimination occurs on hydroxylation, and a value of G(NO - 2) = 0.3 ± 0.02 was determined for this process both by means of electrical conductivity and analytical experiments. No cyclohexadienyl-type radical was observed as reaction product of either hydroxyl radicals or hydrogen atoms. It is concluded that OH radicals react with nitroaniline to form a π-complex which has certain radical characteristics; furthermore, that hydrogen atoms also react within the aromatic ring, but that hydrated electrons react with the NH 2 group.