In order to intensify a phase transfer catalytic reactor with the third liquid phase, it is necessary to optimize multiple operation variables that are concerned with the mass transfer rate. In the present paper, we propose a systems approach by application of a rate based model for mass transfer between two phases. Application of the developed rate based model performs simulation with higher accuracy than the conventional partition equilibrium model, for numerical analysis of behavior of a batch process for the synthesis of 4-benzyloxy-vanillin by using tetrabutylammonium bromide as the phase transfer catalyst. Moreover, influences of the rotational speed of the impeller on changes in the overall mass transfer coefficients are analyzed by using estimation equations for the Sauter diameter and the specific interfacial area of the dispersed phase. Consequently, it is found that the assumption of spherical droplets for the dispersed phase is not applicable in the application of the estimation equations. Then, the sensitivity analysis based on the rate based model demonstrates that characteristics of liquid-liquid dispersion in the agitated triphase reactor is complex due to the role of the third phase as a surfactant.