Patent ID: 8513444

Claim:
A method of producing ethylene oxide comprising: passing a reaction mixture comprising ethylene, oxygen and a gaseous chlorine-containing promoter species over a supported catalyst comprising silver and a promoting amount of rhenium to undergo an epoxidation reaction at a first operating condition to form ethylene oxide in a reactor; and subsequently performing the epoxidation reaction within the reactor at a preferred operating condition, wherein the preferred operating condition is characterized by an efficiency of the epoxidation reaction toward the ethylene oxide, wherein the efficiency is lower than that of a maximum efficiency achievable at an operating temperature corresponding to the preferred operating condition, wherein the preferred operating condition is further characterized by a productivity of the epoxidation reaction, wherein the productivity of the epoxidation reaction at the preferred operating condition is higher than that obtained at the maximum efficiency achievable at the operating temperature corresponding to the preferred operating condition and wherein the preferred operating condition is further characterized by an overall catalyst chloriding effectiveness value that is higher than when the epoxidation reaction is performed at the maximum efficiency achievable at the operating temperature corresponding to the preferred operating condition and wherein the reactor is operated at the preferred operating condition for a cumulative ethylene oxide production of at least 250 kmole per m 3 of the catalyst.