Reactions between aromatic nitro-compounds and hydroxylamines in alkaline solution. Part I. Kinetic studies

Abstract

An e.s.r. study shows that the initial reactions in alkali under nitrogen between an aromatic nitro-compound and hydroxylamine or a monosubstituted hydroxylamine are (i)–(iv). K,k1, and k2 have been evaluated by monitoring RNHOH + OH– [graphic omitted] RNHO–+ H2O (i), ArNO2+ RNHO– [graphic omitted] (ArNO2·)–+ RNHO·(ii), 2(ArNO2·) [graphic omitted] Products (iii), 2RNHO· [graphic omitted] Products (iv) the build-up and decay of (ArNO2·)– radical-anions by use of p-nitrobenzoic acid and N-methyl-, N-benzyl-, and N-diphenylmethyl-hydroxylamines.With hydroxylamine the kinetic measurements are much less accurate owing to a pseudo-unimolecular gas evolution which appears to come from reactions (v). Hydroxylamine is also destroyed by reaction (vi), the 2NH2O·→ H4N2O2→ N2+ 2H2O (v), ArNO + 2NH2OH → ArN3+ 3H2O (vi) nitroso-compound being formed by the disproportionation (iii).