Nucleophilic Substitution on Nitrobenzene Derivatives in W/O Microemulsions

Nucleophilic substitution of nitrobenzene derivatives with various amines was conducted so as to clarify the effects of W/O microemulsion surface on reaction rates. In W/O microemulsions produced in octane by sodium bis (2-ethylhexyl) sulfosuccinate (AOT) or cetyltrimethylammonium bromide (CTAB), water-soluble sodium 2, 4, 6-trinitrobenzenesulfonate or octane-soluble 2, 4-dinitrofluorobenzene was found to react with either a water-soluble amine (sodium β-aminoethane sulfonate, sodium glycine, or sodium phenylalanine), or an octane-soluble amine (benzylamine, 1-phenylethylamine, or octylamine). Reaction rate was dependent on ionic charge of surfactant and reagents, surfactant concentration, and [water] / [surfactant] molar concentration ratio (w). Based on a pseudo-phase model, the present results were explained as arising from local concentrations of nitrobenzene derivative and amine at the microemulsion surface due to electrostatic binding of ionic reactants and amphiphilic binding of neutral reactants.