Process for preparing silver catalyst for ethylene epoxidation

摘要

An improved silver catalyst for the oxidation of ethylene with molecular oxygen is made by impregnating a porous support with a silver salt of an acid; subjecting the impregnated support to a multi-stage activation in an atmosphere containing less oxygen than air by heating at a first temperature in the range of 150 DEG to 200 DEG C. for less than an hour, heating at a second temperature in the range of from greater than 200 DEG C. to 300 DEG C. for less than one hour, heating at a third temperature in the range of from greater than 300 DEG C. to 400 DEG C. for less than one hour and finally heating at a fourth temperature in the range of from greater than 400 DEG C. to 500 DEG C.; and post impregnating the support with an alkali metal, preferably cesium, from an anhydrous alcohol solution followed by washing with alcohol solvent and rapid drying to produce a finished catalyst having from 1-6x10-3 gew of the alkali metal per kg of catalyst.