On the Ability of Nitrous Oxide to Convert Hydrated Electrons into Hydroxyl Radical

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Abstract
The nature and reactivity of the oxidizing entity formed when N2O scavenges X-ray-induced hydrated electrons (e-ag) has been studied. In the presence of N2O, pyridoxal-5-phosphate (PLP) was degraded with a G-value twice that found in O2. The results show that N2O converts e-aq into an oxidizing species which in this system is stoichiometrically equivalent to the OH radical. The hydroxylation and degradation of p-aminobenzoic acid (PABA) was increased by N2O in the absence of O2 to the same extent as by the electron scavenger NO3-. In a mixture of 20% O2 and 80% N2O the degradation was the same as in O2. The results can be accounted for by the fact that N2O removes e-aq thus interfering with the back reactions that otherwise reduce the yield of degradation of PABA. The results indicate that at neutral pH, N2O- does not decompose spontaneously to OH radicals at any appreciable rate. They suggest that N2O- radicals may have an appreciable life-time at neutral pH and that this radical is less reactive than OH radicals, but more reactive than O2- and potassium nitroso disulfonate radicals.