Epoxidation catalyst, a process for preparing the catalyst, and a process for the production of an olefin oxide, a 1,2-diol, a 1,2-diol ether, a 1,2-carbonate, or an alkanolamine

1. A catalyst for the epoxidation of an olefin comprising a carrier and, deposited on the carrier, silver, a rhenium promoter, a first co-promoter, and a second co-promoter; wherein

the quantity of the rhenium promoter deposited on the carrier is at least 2 mmole/kg, relative to the weight of the catalyst;

the first co-promoter is selected from the group consisting of sulfur, phosphorus, boron, and mixtures thereof;

the second co-promoter is selected from the group consisting of tungsten, molybdenum, chromium, and mixtures thereof; and

the total quantity of the first co-promoter and the second co-promoter deposited on the carrier is at most 3.8 mmole/kg, relative to the weight of the catalyst.

2. The catalyst as claimed in claim 1 , wherein the quantity of the rhenium promoter is from 2 to 10 mmole/kg, relative to the weight of the catalyst.

3. The catalyst as claimed in claim 1 , wherein the total quantity of the first co-promoter and the second co-promoter is at most 3.5 mmole/kg, relative to the weight of the catalyst.

4. The catalyst as claimed in claim 1 , wherein the total quantity of the first co-promoter and the second co-promoter is at least 0.5 mmole/kg, relative to the weight of the catalyst.

5. The catalyst as claimed in claim 1 , wherein the second co-promoter comprises tungsten.

6. The catalyst as claimed in claim 1 , wherein the second co-promoter comprises molybdenum.

7. The catalyst as claimed in claim 1 , wherein the first co-promoter comprises sulfur.

8. The catalyst as claimed in claim 1 , wherein the catalyst further comprises a further element selected from the group consisting of nitrogen, fluorine, alkali metals, alkaline earth metals, titanium, hafnium, zirconium, vanadium, thallium, thorium, tantalum, niobium, gallium and germanium and mixtures thereof.

9. The catalyst as claimed in claim 8 , wherein the alkali metals are selected from the group consisting of lithium, sodium, and cesium.

10. The catalyst as claimed in claim 1 , wherein the catalyst further comprises deposited on the carrier a potassium promoter in a quantity of at least 0.5 mmole/kg, relative to the weight of the catalyst.

11. The catalyst as claimed in claim 1 , wherein the catalyst further comprises deposited on the carrier a potassium promoter in a quantity of at least 1.5 mmole/kg, relative to the weight of the catalyst.

12. The catalyst as claimed in claim 1 , wherein the catalyst has a water extractable quantity of potassium in the range of from 1.25 to 10 mmole/kg, relative to the weight of the catalyst.

13. The catalyst as claimed in claim 1 , wherein the catalyst has a water extractable quantity of potassium in the range of from 1.5 to 7.5 mmole/kg, relative to the weight of the catalyst.

14. The catalyst as claimed in claim 1 , wherein silver is present in a quantity in the range of 10 to 500 g/kg, relative to the weight of the catalyst.

15. The catalyst as claimed in claim 1 , wherein silver is present in a quantity in the range of 50 to 450 g/kg, relative to the weight of the catalyst.

16. The catalyst as claimed in claim 1 , wherein the molar ratio of the first co-promoter to the second co-promoter is greater than 2.

17. The catalyst as claimed in claim 1 , wherein the molar ratio of the first co-promoter to the second co-promoter is greater than 2 and at most 20.