Industrial production of ε-caprolactone, the monomer of biodegradable polycaprolactone, consists of acetic acid peroxidation and the Baeyer–Villiger oxidation of cyclohexanone in semi-batch reactors. The strong exothermic feature of the latter and ease of ε-caprolactone hydrolysis significantly affects the production efficiency. Here, collective effects of kinetic studies and density functional theory (DFT) calculations reveal activation energy of the Baeyer–Villiger oxidation is higher than that of ε-caprolactone hydrolysis and the hydrolysis barrier is controlled by hydrogen bond energy of the reaction medium. Then, we developed a microreactor system to intensify heat transfer thereby allowing safe and efficient production of ε-caprolactone. A yield of 99.6% was achieved within minutes via consecutive two-step reactions of peroxidation and the Baeyer–Villiger oxidation, as compared with state-of-the-art yield of 96% in hours of industrial operation. The high selectivity is attributed to high reaction temperature allowed by the microreactor and DFT-guided choice of solvent to mitigate the hydrolysis.

中文翻译：

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动力学指导在微反应器系统中高产率和快速生产 ε-己内酯

ε-己内酯（可生物降解的聚己内酯的单体）的工业生产包括半间歇反应器中的乙酸过氧化和环己酮的 Baeyer-Villiger 氧化。后者强烈的放热特性和ε-己内酯的易水解性显着影响生产效率。在这里，动力学研究和密度泛函理论 (DFT) 计算的集体效应表明 Baeyer-Villiger 氧化的活化能高于 ε-己内酯水解的活化能，并且水解能垒受反应介质的氢键能控制。然后，我们开发了一种微反应器系统来加强传热，从而可以安全高效地生产 ε-己内酯。产率为99。通过连续的过氧化和 Baeyer-Villiger 氧化两步反应在几分钟内实现了 6%，而最先进的产率为 96% 的工业操作数小时。高选择性归因于微反应器允许的高反应温度和 DFT 指导的溶剂选择以减轻水解。