Kinetics of the reaction between benzyl bromide (RBr) and sodium benzoate (C6H5COONa, PhCOONa) in liquid-liquid system catalyzed by aliquat 336 (QCl) was investigated in the present study. The yield of product benzyl benzoate (PhCOOR) was obtained above 98% at 70 degreesC within 3 h of reaction using chlorobenzene as the solvent. During the progress of reaction, about 80% of the catalyst was present as the catalytic intermediate in the organic phase, which is generated from the reaction of aqueous sodium benzoate with aliquat 336 at the aqueous-organic interface. When a great excess amount of aqueous reactant was employed, the concentration of catalytic intermediate was kept at near constant after the induction period. A conspicuous reduction of 40% of interfacial tension by forming catalytic intermediate methyltrioctylammonium benzoate (PhCOOQ) was applied to describe the interfacial phenomenon. A kinetic model describing the behavior of interfacial catalysis was proposed, and the experimental data were interpreted as a pseudo-first-order reaction, although the catalytic intermediate was produced in the interfacial re-ion. The effects of temperature, organic solvent and amounts of catalyst were investigated and the apparent activation energy was estimated at 63.96 kJ/mol in chlorobenzene. The present benzylation reaction catalyzed by aliquat 336 shows characteristics of the intermediate in phase-transfer catalysis (PTC). (C) 2003 Elsevier B.V. All rights reserved.