Epoxidation of ethylene by anion radicals of α-oxygen on the surface of FeZSM-5 zeolite

The stoichiometric oxidation of ethylene by anion radicals of α-oxygen, (FeIII−Oradical dot–)α, created on the surface of non-modified and Na-modified FeZSM-5 zeolite was studied in the temperature range from 25 down to −60 °C. Upon extraction, the products were identified using the gas chromatography, gas chromatography–mass spectrometry, and nuclear magnetic resonance. Unlike the oxidation of methane, the reaction С2Н4 + Oα was shown to proceed without hydrogen abstraction from the ethylene (infrared spectroscopy data). It leads to Oα addition over the double Cdouble bond; length as m-dashC bond yielding the ethylene oxide (EO) primary product. Sodium modification of the zeolite strongly increases the selectivity for EO, which attains 80–84% at the reaction temperature of −60 °C. A much lower selectivity at room temperature relates mainly to a secondary reaction of EO with ethylene leading to butyraldehyde. High epoxidizing selectivity of α-oxygen is discussed in relation to the mechanism of ethylene epoxidation on silver catalyst.