To check the kinetics of extraction using hydrated ethanol, two experimental conditions were chosen: C (25 ◦C, ethanol 96%) and D (55 ◦C, ethanol 96% + 20% biodiesel, in mass). Those were the worst and best conditions considered within the limits studied in this work. Table 2 shows the parameters and errors for conditions C and D of extractions using hydrated ethanol, while Fig. 6 shows their means and the fitted second-order and mass transfer models, represented by the dashed and solid lines, respectively. In these kinetics, condition C showed a high correlation with the secondorder kinetic model (R2 =0.9865), while condition D showed a high correlation with the MTKM (R2 = 0.9915). The maximum amount of solute extracted at condition C was slightly higher than 6%, which represents approximately 40% of the maximum amount extracted using anhydrous ethanol (15.1%) at the same conditions. On the other hand, the results obtained at condition D (hydrated ethanol with 20% of biodiesel added as a co-solvent, Fig. 6) were very similar to that using anhydrous ethanol (EtOH) and its mixtures with biodiesel (EtOH5% and EtOH10%) at 55 ◦C, where it was possible
to perform the complete extraction of the soybean oil. However, if there were used contents of biodiesel lower than 20% in condition D, lower extraction rates and lower extraction yields might be achieved.