Formation of Epoxycyclooctane during the Co-Oxidation of Cyclooctene and Alkylbenzenes

Cyclooctene and alkylbenzenes are subjected to co-oxidation in oxygen and a system of two catalysts. Radical catalyst Fe(acac)₃/NHPI mediates the formation of alkylbenzene hydroperoxides, which are consumed in situ during the MoO₃/SiO₂-catalyzed epoxidation of cyclooctene. The chain oxidation rate is limited in cyclooctene and MoO₃/SiO₂, but radical catalyst Fe(acac)₃/NHPI retains fairly high activity in the oxidation of alkylbenzene in hydroperoxide. It is found that isopropylbenzene is a better co-reducing agent than ethylbenzene because it ensures more vigorous and selective formation of epoxycyclooctane. At optimized amounts of components and a temperature of 80°C, selectivity toward epoxycyclooctane reaches 92 and 96% in ethylbenzene or isopropylbenzene, respectively, with more than 70% conversion of cyclooctene.