Pulsradiolytische Untersuchung primärer Schritte der Oxidation von Aminen in wäßriger Lösung / Pulsradiolytic Investigation of the Primary Steps in the Oxidation of Amines in Aqueous Solution

Abstract

The OH radical rapidly reacts with CH 3 NH 2 and C 6 H 5 NH 2 but reacts slower with CH 3 NH 3 ⊕ , respectively C 6 H 5 NH 3 ⊕ . In the reaction with methylamine. the complex is formed which loses water with τ½=26 µs. The addition of OH to the aromatic ring of aniline occurs in 20% of the reactions. The hydroxy-amino-cyclohexadienyl radical has its absorption maximum at 3500 A. It decays by elimination of water to yield the anilino radical C 6 H 5 NH (τ½= 5.7µs at pH = 7), H ⊕ and OH ⊖ ions catalyse the decay. In 80% of the reactions. · OH adds to the amino group of aniline. The subsequent loss of water or of OH ⊖ occurs rapidly (<1 µs). However, the basic form of the addition complex decays much more slowly (τ½=10 µs at pH= 13.7). The pK-value of the equilibrium is estimated to be equal to 11 — 12. The absorption spectra of C 6 H 5 NH 2 ® and the pK-value of 7.0 of C 6 H 5 NH 2 ⊕ first described by LAND and PORTER are confirmed.