Pathways for the decomposition of alkylaryltriazenes in aqueous solution

Abstract

Primary alkylaryltriazenes give solvent-equilibrated alkanediazonium ions and anilines in aqueous solution at 25 °C by two processes. The first, an A–S_E2(N) reaction, involves immobilisation of a molecule of catalysing acid, and a transition state in which the proton is essentially completely transferred and little breakage of the N–N bond has occurred. The structure of this transition state varies with the strength of the catalysing acid and the pK_a of the liberated aniline in a way interpretable in terms of a More O'Ferrall–Jencks diagram. The second process is the departure of aniline anion without acid assistance. The first process is governed by positive, the second by negative, β_1g values.