Liquid–liquid mass transfer in a rotor–stator spinning disc reactor

► The liquid–liquid flow behaviour and mass transfer rates for a rotor–stator spinning disc reactor are reported. ► The measured mass transfer rate is at least 25 times higher compared to packed column. ► This makes that the rotor–stator spinning disc reactor is a promising multiphase reactor. This paper presents the liquid–liquid flow behaviour and the liquid–liquid mass transfer rates for a rotor–stator spinning disc reactor, with an axial disc spacing of 1mm, a rotor radius of 0.066m, and rotational disc speeds up to 1600rpm. The liquid–liquid mass transfer rate is determined from extraction experiments of benzoic acid from n-heptane to water. For the calculation of the overall mass transfer rate the dimerization and acid dissociation equilibria are taken into account. Three flow patterns are characterized. Up to 100rpm continuous radially inwards spiralling n-heptane patterns are observed. Between 100rpm and 300rpm this continuous spiral changes to spiralling n-heptane droplets. Above 300rpm fully dispersed phase flow is observed. The overall mass transfer rate increases from 0.17 mORG3 mR−3 s−1 at 100rpm and a water flow rate of 2.5×10−6 mAQ3 s−1 (water: n-heptane=1.1:1) to 51.47 mORG3 mR−3s−1 at 1600rpm and a water flow rate of 12.5×10−6 mAQ3 s−1 (water: n-heptane=5.6:1). These mass transfer rates are at least 25 times higher compared to those in packed columns, and at most 15 times higher compared to mass transfer rates in state of the art microchannels.