Annular centrifugal extractors (ACE) based on Taylor-Couette flow have been studied for axial mixing and mass transfer with chemical reaction. The residence time distribution (RTD) was measured in three size extractors having 50,150 and 250 mm rotor diameter. The power consumption per unit mass in the annular region was in the range of 25-750 W/kg. Alkaline hydrolysis of a chloro-substituted ester was carried out in ACE 50 at various rotor speeds. The effect of helical baffles on axial mixing and in turn on chemical reaction was observed by conducting two separate sets of experiments, viz., in the absence and in presence of helical baffles. An excellent agreement has been observed between the experimental results and the CFD predictions of the extents of axial mixing and chemical reaction. (C) 2013 Elsevier Ltd. All rights reserved