Glycerolysis–interesterification in high-shear reactor using sodium silicate catalyst: effect of mixing rate on reaction kinetics

High-shear reactor (HSR) was used to improve glycerolysis-interesterification of immiscible fluids (palm stearin-olein blend and glycerol) to synthesize products containing high monoacylglycerol (MAG) and diacylglycerol (DAG). This study aimed to investigate the effect of mixing rate on the reaction kinetics of immiscible reactants in an HSR and to establish an equation for the relationship between mixing rate and reaction rate constants. The result showed that a high mixing rate (above 1000 rpm) improved the reaction at a relatively low temperature (110 °C). The TAG conversion rate increased about 1.25 times with the mixing rate. The mixing rate at 2000 rpm provided the highest TAG conversion (51.08). The interfacial area between immiscible reactants in glycerolysis-interesterification was improved by emulsion formation using HSR. The initial reaction rate constant increased with the mixing rate, with the highest initial reaction rate constant obtained at 2000 rpm. The power law equation expressed the relationship between mixing rate and initial reaction rate constant, with the power law constant at 3.43 × 10−6 and exponent value at 0.73. The best operating conditions were at 110 °C and 2000 rpm, and the initial reaction rate constant was 1.06 × 10–3. The mixing rate did not significantly affect the products' properties, such as melting point, hardness, and color profile. In summary, using HSR is a better alternative to improve the reaction of immiscible reactants in glycerolysis-interesterification. The mixing rate improved the glycerolysis–interesterification rate without altering the product's physical properties.