Electrochemical Study of the S_N2 Reaction of 1-p-Toluenesulfonyl-2,4-dinitronaphthalene with Hydroxide Ions at the Nitrobenzene-Water Interface

The rate of the interfacial nucleophilic reaction of 1-p-toluenesulfonyl-2,4-dinitronaphthalene (TSDNN) with OH^- ions at the polarized nitrobenzene (NB)-water (W) interface was studied using a polarographic technique. The TSDNN partitioned into the aqueous phase underwent a displacement of the p-toluenesulfonyl moiety with OH^-. The transfer of one of the products, 2,4-dinitronaphthalate (DNN^-), from the W phase to the NB phase was monitored as the current across the interface. The rate constant of the reaction of TSDNN with OH^- in the aqueous phase was estimated to be 1.03±0.23 dm³ mol^-1 s^-1 at 25°C, which is ten-times higher than the rate constant of the displacement of 2,4-dinitrofluorobenzene with OH^- in the aqueous phase, 1.01±0.13×10^-1 dm³mol^-1 s^-1. The contribution from the reactions in the NB phase and at the interface to the formation of DNN^- seems to be negligible, suggesting the absence of an interfacial facilitation of the reaction.