The goal of this work was to find a model for the calculation of the industrial scale column serving to the extraction of mercaptans from hydrocarbon fractions with alkaline solutions. The work is based on original experiment at laboratory and pilot scale. A simple, easy to handle model with a good resolution was obtained. The equation for the hydrodynamic behaviour of the column shows the dependency of the column capacity on the physical properties of the liquid-liquid system and the geometrical characteristics of the packing. The equation for the mass transfer shows the dependency of the overall mass transfer coefficients on the mercaptans acidity, concentration of the caustic and geometrical characteristics of the packing. The statistical tests applied on the mass transfer coefficients equation gave good results. (c) 2007 Elsevier B. V. All rights reserved.