Patent ID: 8742146

Claim:
A process for improving the selectivity of an ethylene epoxidation process employed in a reactor, said process comprising: (a) contacting an epoxidation catalyst comprising silver and rhenium with a feed comprising ethylene, oxygen, and an organic chloride for a period of time T 1 sufficient to produce at least 0.1 kilotons of ethylene oxide per cubic meter of epoxidation catalyst; (b) subsequent to step (a) and over a period of time T 2 , (i) reducing the quantity of organic chloride added to the feed by at least 50% and (ii) increasing the reactor temperature by about 1 to 30° C.; and (c) subsequent to step (b), increasing the quantity of organic chloride added to the feed such that the quantity present in the feed is between 80 and 120% of the quantity that was present in the feed prior to step (b), and reducing the reactor temperature to within 5° C. of the prior reactor temperature.