Reaction of 2,6-dinitroanisole with cyclohexylamine in toluene–octanol binary solvents. Further support for the ‘dimer nucleophile mechanism’ in aromatic nucleophilic substitution

Abstract

The reaction of 2, 6-dinitroanisole with cyclohexylamine in toluene, octanol and toluene–octanol mixtures has been studied at several amine concentrations. The reactions in toluene and in octanol–toluene mixtures up to 30% octanol show a third-order kinetic dependence on [amine]. Although the reaction rates in toluene and octanol are very similar, addition of small amounts of octanol to the toluene solution diminishes the rate of reaction, reaching a minimum value at 30–50% octanol, after which the rate increases almost linearly with the octanol content. These and other results, here described, are satisfactorily explained by the previously proposed ‘dimer nucleophile mechanism’. Previously reported similar observations in methanol–benzene mixtures were criticised as being due to the reversibility of the reaction. The present results confirm the previously reported mechanism and the irreversibility of the reaction under the reaction conditions.