| 摘要 |
This invention relates to an epoxidation catalyst having improved selectivity stability which catalyst comprises silver, a promoting amount of alkali metal, a promoting amount of magnesium, a promoting amount of rhenium and, optionally, a promoting amount of rhenium co-promoter selected from sulphur, molybdenum, tungsten, chromium and mixtures thereof, supported on a carrier comprising at least 85 percent by weight of alpha alumina and from 0.001 to 2 percent by weight (measured as the element) of magnesium in the form of an oxide. |
