Catalytic properties of a ternary oxide of silver, copper, and manganese in the reaction of ethylene oxidation

A ternary oxide of silver, copper, and manganese (Ag₂CuMnO₄) is prepared by hydrothermal synthesis in an alkaline medium in the presence of sodium peroxodisulfate. The obtained product with the delafossite structure has no admixtures of other crystallized phases and is tested as an ethylene oxidation catalyst. The catalytic properties of the ternary oxide are modified by pretreatments in inert (He, T = 400-600 °C) and reducing (1% CO/He, T = 200 °C) media resulting in partial or complete destruction of the pristine structure. It is established that pre-treatment of the ternary oxide diminishes its catalytic activity in the ethylene oxidation reaction. The main reaction products are ethylene oxide, acetaldehyde, carbon dioxide, and water; their yields depend on the pretreatment type and the changes during the heating–cooling cycle.