Determination and discussion of apparent reaction kinetics of liquid diacyl peroxide synthesis in a microreactor

Organic peroxides are highly reactive and hazardous substances requiring extra care during their synthesis and handling, especially the exothermic peroxidation reaction. In our previous study, efficient and safe synthesis of di-(3,5,5-trimethylhexanoyl) peroxide was realized by exploiting microreaction technology. For better understanding and guidance of the process, the apparent reaction kinetics of its synthesis in a microreactor is determined herein. Results show the reaction order of NaOH, H2O2, and 3,5,5-trimethylhexanoyl chloride are 0, 2.6, and 2 respectively. The pre-exponential factor (A) and activation energy (Ea) are 221 L3.6/(mol3.6·s) and 25.0 kJ/mol respectively. With the determined kinetics, three discussions are made. First, in terms of reactant usage optimization, the H2O2 concentration is key to affecting the reaction rate. Second, temperature profile simulation confirms that microreactors are thermally safer than traditional reactors. Third, for the reaction mechanism, it is proposed that perhydroxyl ions generated from H2O2 deprotonation are nucleophiles that are involved in the peroxidation in organic phase. This work is the first to determine the reaction kinetics of di-(3,5,5-trimethylhexanoyl) peroxide synthesis in a microreactor which not only provides guidance for related processes but is also informative to other liquid diacyl peroxides.