Process intensification using a spiral capillary microreactor for continuous flow synthesis of performic acid and it’s kinetic study

Abstract

The continuous production of performic acid is getting significant importance due to it’s versatile oxidizing properties in various applications such as in the food, oil and chemical industries. In this work, an attempt has been made for synthesis of performic acid in a continuous flow microreator in polytetrafluoroethylene spiral capillary microreactor (PSCMR) with and without homogeneous catalyst. The effect of catalyst concentration, hydrogen peroxide concentration, temperature and radius of curvature on formation of perfomic acid was studied. The maximum conversion of FA was obtained within 6 min at 30 °C and 4 mol% catalyst. The maximum PFA was obtained (5.175 mol/L) when the reaction was performed in spiral capillary microreactor having 13.25 mm radius of curvature (Number of turns = 21). However, in the radius of curvature of 18.25 mm (Number of turns = 15) and 23.25 mm (Number of turns = 12) of the PSCMR gave 3.393 mol/L and 3.105 mol/L of PFA respectively at residence time of 9 min. Based on the kinetic equations and experimental data, the kinetic constants were determined. Thus, the average rate constants for forward and backward reaction are 0.0097 and 0.04354 L/(mol min) respectively. Based on the kinetic data, it was found that the activation energies of PFA synthesis and hydrolysis were 31.716 and 13.701 kJ/mol respectively.