Pulse radiolysis: evidence for the reaction of HO2 with NO2 in aqueous solution

Abstract

Nitroform is the major radiation induced species observed after the pulse radiolysis of acidic oxygen saturated solutions of tetranitromethane (TNM) and formic acid. It is formed in three stages, of which a major component at pH < 3 is first order with t1/2 = 49 s, independent of [TNM] and pH. Evidence is provided for the reactions[Formula: see text]in which k14 = 0.014 ± 0.002 s−1. The data support similar conclusions reached previously in rapid mixingexperiments (1) from which it was concluded that k3 = 4 × 109 dm3 mol−1 s−1.Analysis of the fastest component of nitroform production over the pH range 1–4 shows that the COOH radical reduces TNM to nitroform with a rate constant about four times greater than that for its reaction with oxygen to produce HO2.