Decomposition, aniline radical cation

FIGURE 37. Schematic potential energy profiles illustrating the decomposition of aniline radical cation. Relative energies in kJ mol 1 were obtained from UB3LYP/6-311++G(d,p) + ZPE calculations... 

Decomposition of aniline radical cation HNC versus HCN elimination... 

FIGURE 38. The mechanism proposed for the decomposition of aniline radical cation leading to a HNC formation... 

Induced decomposition occurs particularly rapidly on addition of amines, which explains the explosive decomposition of benzoyl peroxide in the presence of amines. It proceeds, for example, in the case of benzoyl peroxide and dimethyl aniline via radical cations as follows ... 

It is assumed that nitrous acid forms in situ under the Knoevenagel diazotizaiton condition, which then combines with aniline to give a diazohydroxide, which can decomposes to yield the phenyl radical. However, in the presence of a strong acid, the diazohydroxide is further protonated and converted into the corresponding diazonium salt which may undergo a heterolytical or homolytical decomposition to give radicals or a cation intermediate, as shown below. 

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