Process for preparing an alkali metal-promoted silver catalyst

摘要

A supported silver catalyst for the oxidation of ethylene with molecular oxygen to ethylene oxide is made by depositing silver on a support capable of selectively adsorbing alkali metals, activating the silver under conditions chosen to provide the optimum selectivity to ethylene oxide and thereafter depositing an amount of an alkali metal sufficient to increase selectivity of the silver catalyst above its alkali-free state. The catalyst most preferably employs a ceramic support having a surface area of 0.3-0.8 m2/gm. The amount of alkali metal on the finished catalyst is most preferably 50-300 ppm by weight. The catalyst may also include additional promoters, such as the alkaline earth metals, preferably barium.