Dehydrochlorination of β-chlorohydrin in continuous microflow system: Reaction kinetics and process intensification

Abstract

Glycidyl esters, as a class of terminal epoxides, are important raw materials for the synthesis and modification of epoxy resins. Their synthetic routes via the dehydrochlorination of β-chlorohydrin esters are typically conducted under heterogeneous condition. Under the control of multiphase mass transfer, the inherently fast reaction can exhibit a very low observed reaction rate. Here we developed a continuous microflow system to determine the kinetic parameters of dehydrochlorination in the presence of aqueous NaOH solution. The same device was applied for the continuous production of glycidyl esters, and the conditions including flow velocity, alkali concentration, phase ratio and temperature were fully optimized. Comparing the obtained reaction performances in the microreactor with the conventional batch reactors, the required reaction time was shortened by 1/20 and the space–time yield was increased by 15 times, which is attributed to the mass transfer enhancement and the continuous operating mode. Finally, a mathematical model was established to calculate the volumetric mass transfer coefficients, whose value were in the range of 0.005–0.03 s−1. The established microflow system and research methods could have high merit for guiding the kinetic studies and process intensification of other dehydrohalogenation reactions.