This work studies the kinetics of a reaction known to occur in the liquid-liquid interfacial monolayer : the butylation of phenylacetonitrile with 1-bromobutane in the presence of aqueous sodium hydroxide. The reaction is conducted at a flat liquid-liquid interface in the absence of a phase-transfer catalyst. Effects of various operating parameters, such as temperature, impeller speed, interfacial area, concentration of the anions in the aqueous phase, and mole ratio of the reactants, on the rate of the reaction have been studied. The evidence gathered in this study further supports the interfacial reaction hypothesis. A model for the kinetics of the reaction is proposed. Interfacial concentrations of the reactants required for estimating the intrinsic interfacial rate constant have been determined from their bulk concentration through the application of the interfacial adsorption isotherm. The parameters of the isotherm are determined through interfacial tension measurements. The proposed model is shown to fit the experimental data satisfactorially.