Evidence for the Addition of the Superoxide Anion to the Anti-Oxidant n-Propyl Gallate in Aqueous Solution

Abstract

n-Propyl gallate reacts with the superoxide radical anion in aqueous solution (k = 5.1 × 10⁵ mol⁻¹ dm³s⁻¹). The spectrum of the transient species so formed has been measured (absorbance maximum at 550nm, ϵ = 1360mol⁻¹dm³cm⁻¹). Electron or H atom transfer processes as well as proton abstraction have been excluded as possible mechanisms, and it is proposed that an addition reaction takes place.

Key Words:

• Superoxide
• anti-oxidant
• n-propyl gallate
• pulse radiolysis