Patent ID: 7932407
Filing Date: 2011-04-26
Classification: B01J,C07C,C07D,Y02P

Abstract:
1. A process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin, oxygen and an organic halide, in the presence of a catalyst comprising silver and rhenium deposited on a carrier, wherein the catalyst comprises rhenium in a quantity from 0.2 to 0.9 mmole/kg, relative to the weight of the catalyst, and 0.0001 to 0.0012 mmole/m 2 , relative to the surface area of the carrier, and a tungsten copromoter in a quantity of from 0.1 to 0.75 mmole/kg, relative to the weight of the catalyst, and in which process the reaction temperature is increased to at least partly reduce the effect of loss of activity of the catalyst while the organic halide is present in a relative quantity Q which is maintained constant, which relative quantity Q is the ratio of an effective molar quantity of active halogen species present in the feed to an effective molar quantity of hydrocarbons present in the feed and wherein the selectivity of the catalyst after 1.6 kT/m 3 of ethylene oxide production decreases no more than about 3 mole %.