Reaction of radiolytically generated hydroxy radicals with maleic hydrazide

Abstract

Pulse radiolysis has been used to study the reaction of hydroxyl radicals with maleic hydrazide. The rate constants of OH˙ with the neutral hydrazide and its monoanion were found to be (2.9 ± 0.1)× 10⁹ dm³ mol^–1 s^–1 and (4.2 ± 0.1)× 10⁹ dm³ mol^–1 s^–1, respectively. In the reaction with the hydrazide monoanion 2/3 of the OH˙ yield diazasemiquinone radicals. The remaining 1/3 of the OH˙ radicals are proposed to yield an OH˙ adduct to the CC bond.

In the reaction with the neutral hydrazide no diazasemiquinone was detected. The radicals generated in this reaction are proposed to be OH˙ adducts. They are found to react with O₂ to yield peroxy radicals.

From product analysis it is concluded that O₂ reacts with the OH˙ adduct of the monoanion to yield a peroxy radical. The reaction of this peroxy radical with the diazasemiquinone is proposed to yield maleic acid.