A reaction of dibromo-o-xylene and 1-butanol to synthesize diether compound was carried out under two-phase phase-transfer catalysis (PTC) conditions. Mono-bromo-substituted product (o-bromomethyl 1-butanoxymethyl benzene) and dibromo-substituted product (o-di(1-butanoxymethyl)benzene) are both produced from the reaction. Rational reaction mechanism and kinetic model were built up by considering the reaction in aqueous and organic phase, the mass transfer of catalysts between two phases and the phase equilibrium of the catalysts between two phases. The concentration of the active catalyst, identified by instruments, was measured during the reaction. The two apparent rate constants and the two intrinsic rate constants in the organic phase were both obtained via experimental data and the technique of the parameter estimation. Effects of agitation, amount of water, catalysts, amount of tetrabutylammonium bromide (TBAB) catalyst, amount of potassium hydroxide, organic solvents and the temperature on the conversion and the rate constants were investigated in detail. The results are explained satisfactorily of the interaction between the reactants and the environmental species. (C) 2002 Elsevier Science B.V. All rights reserved.