Apparent Kinetics Study and Continuous Synthesis of Di-tert-butyl Hydroperoxide in a Microreactor

Di-tert-butyl hydroperoxide (DTBP) is mainly used as a polymerization initiator, with an annual global market of ∼$30 million. Industrial production of DTBP is carried out via the acid-catalyzed peroxidation of tert-butanol (TBA) by H2O2 in batch reactors. Because of its highly exothermic and reactive nature, a dropwise feeding method is required, leading to a low production efficiency. In addition, the large liquid holdup in batch operations poses a significant safety risk of runaway reactions. Here, we report a highly efficient, continuous-flow approach for the production of DTBP in a microreactor system, achieving a DTBP selectivity of 96.5% and a DTBP yield of 93.6% at a TBA conversion of 97.0% within a residence time of 420 s. This performance outperforms conventional batch operations, which typically yield ∼92% DTBP and require several hours for feeding and reaction. The markedly enhanced production efficiency is owed to the improved heat-removal capacity of the microreactor, which eliminates the need for dropwise feeding and allows the reaction to safely proceed at higher temperatures. The microreactor system also exhibits precise temperature control during the apparent kinetics measurements for DTBP formation, with any thermal runaway-induced temperature rise remaining below 3 °C. Density functional theory calculations indicate a lower energy barrier for the second step (acid-catalyzed condensation to form DTBP) than for the first step (peroxidation of TBA to tert-butyl hydroperoxide), consistent with the trend in apparent activation energies from kinetic studies. These kinetic and mechanistic insights can guide the optimization of continuous-flow DTBP production with an enhanced efficiency and safety.