Process for the preparation of a supported silver catalyst

Claim 1

A process for the preparation of a supported silver catalyst suitable for the production of ethylene oxide by the controlled, vapor phase, partial oxidation of ethylene with molecular oxygen, said catalyst preparation process comprising the following steps: a. impregnating a porous refractory support with a liquid containing a compound or complex of silver by immersing said support in said liquid and maintaining the support and the liquid in contact until the liquid has been absorbed into the pores of the support; b. separating the thus-impregnated particles from any non-absorbed remainder of said liquid; c. activating the thus-impregnated particles by converting the silver compounds or complex to at least one member of the group consisting of silver oxides and elemental silver, at least part of the silver being in elemental form, said conversion being accomplished by heating the impregnated particles in the presence of an essentially oxygen-free inert gas to a temperature at which the silver compound or complex decomposes to yield, at least in part, elemental silver; d. heating the activated particles in the presence of an oxygen-containing gas at a temperature in the range of 160° - 300° C. for a period of from 0.5 to 24 hours prior to step (e) hereinafter described; e. depositing upon the activated particles from 4 × 10 -5 to 4 × 10 -3 gram atoms per kilogram of catalyst of at least one alkali metal of the group consisting of potassium, rubidium, and cesium, said alkali metal being in the form of a salt in solution in a solvent; f. removing the solvent employed in step (e).