| 摘要 |
A silver catalyst containing lithium and cesium as promoters for the direct oxidation of ethylene with oxygen to give ethylene oxide is applied to a porous carrier and essentially consists of alpha -alumina and contains certain amounts of soluble calcium, aluminum, potassium and sodium salts. The carrier has a BET surface area of from 0.4 to 0.8 m2/g, a pore volume of not less than 0.45 ml/g, the pores being equally accessible to cold and warm water, a bulk density of less than 700 kg/m3 and a shape which, in the reactor, provides a geometrical surface area of not less than 600 m2/m3, on which more than 13% by weight of silver are applied as active component and more than 115 kg of silver are available per m3 of reactor, and from 100 to 300 ppm by weight of lithium and from 200 to 600 ppm by weight of cesium are present as promoters. A process for the preparation of the silver catalyst and its use for the oxidation of ethylene are described.
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