Process for the oxacylation of olefins in the gaseous phase

In the process for oxacylation of ethylene, propylene or isobutylene in the gaseous phase in the presence of oxygen and a carrier catalyst consisting essentially of palladium salts or palladium salts and as additives therefor alkali and alkaline earth metal salts, gold, gold salts, cadmium, cadmium salts, bismuth, bismuth salts, the improvement consisting essentially of adding a barium carboxylic acid aurate of a carboxylic acid having from 2 to 10 carbon atoms to said carrier catalyst and oxacylating said ethylene, propylene or isobutylene with said catalyst.