Efficient Continuous-Flow Synthesis of Methyl Ethyl Ketone Peroxide in a Microreaction System

Abstract

Organic peroxides are important to the fine chemical industry because of their applications in polymerization and curing initiators. However, as a hazardous process, the peroxidation reaction to synthesize organic peroxide involves explosive intermediates, sensitive products, and exothermic reactions, resulting in many accidents reported each year. Recently, continuous-flow microreaction synthesis has emerged as a new technology for producing chemicals efficiently and safely. This work introduced a novel efficient continuous-flow microreaction system to intensify the methyl ethyl ketone peroxide (MEKPO) production process. A microreaction platform for MEKPO synthesis was established, with quantitative methods to uncover the effects of reaction conditions on the kinetics and thermodynamics of the reaction, which had never been reported before. Then, a continuous-flow microreaction process was developed to replace the existing batch method by optimizing the peroxidation reaction, phase separation, and dilution steps. Compared to the current batch process for the commercial MEKPO product V688, the conversion of MEK and H2O2 reached 69.11% (4% higher than V688) and 70.01%, respectively, when the nitric acid concentration in H2O2 was 0.5 wt % and the reaction reach time was 270 s at a temperature of 25 °C. Also, our product can achieve the same performance (gel time and gel to cure time) as V688 with a lower active oxygen content (9.5% for V688, 8–9% for microreaction products). These results indicated that both the safety of the peroxidation reaction process and the activity of products were improved by replacing the existing batch process with our continuous microreaction process, which provides great potential for the industrial scale-up of such a system.