In this work mass transfer phenomenon of liquid-liquid extraction process with structured packing was modeled. The model was validated by means of fluid-dynamic and mass transfer tests, for mass transfer from the continuous to the disperse phase with n-butanol/succinic acid/water system. The effect on hold-up and outlet concentration profiles of each phase were evaluated when the incoming flow of the disperse phase was disturbed between 10 and 30%. Surface velocity of each phase and hold-up were considered in the model as functions of time. The continuous phase dispersion phenomenon was also taken into account. Deviation percentage average of 8% between the experimental data and the simulation results of the disperse phase composition in steady state were obtained. For the dynamic model the inclusion of the dispersion effect of the disperse phase and more experimental tests are recommended. (c) 2007 Elsevier Ltd. All rights reserved.