A new separator design for liquid-liquid systems has been proposed to decrease the coalescence time of dispersed phase drops. Aiming at making the separation process more efficient, the present work studies hydrodynamics and mass transfer in the mixer to estimate the overall mass transfer coefficient relative to the aqueous (water + oil) and organic (turpentine) phases involved. Samples were collected at the inlet and at the outlet of the system. The analyses were performed using the oil and grease content technique. A mass balance in the liquid phase calculated in the mixer allows us to determine the mass transfer coefficient, thereby optimizing the system. A correlation equation was found for the mass transfer coefficient as a function of the variables studied in the process. Transfer optimization in the mixing chamber will contribute significantly to an increase in the overall separation efficiency of the device.