Silver-containing catalysts, the manufacture of such silver-containing catalysts, and the use thereof
View Patent ↗A high activity and high selectivity silver catalyst comprising silver and, optionally, one or more promoters supported on a suitable support material having the form of a shaped agglomerate. The structure of the shaped agglomerate is that of a hollow cylinder having a relatively small inside (bore) diameter. The catalyst is made by providing the shaped material of a particular geometry and incorporating the catalytic components therein. The catalyst is useful in the epoxidation of ethylene.
1. A catalyst, which catalyst comprises silver deposited on a shaped support material having a hollow cylinder geometric configuration such that the length-to-outside diameter ratio of said shaped support material is in the range of from about 0.3 to about 2 and the internal diameter is in the range upwardly to 30 percent of the outside diameter of said shaped support material.
2. A catalyst as recited in claim 1 , wherein silver is present in a quantity in the range exceeding 15 weight percent of the total weight of the catalyst.
3. A catalyst as recited in claim 2 , wherein silver is present in a quantity in the range of exceeding 20 weight percent to and at most 50 weight percent, of the total weight of the catalyst.
4. A catalyst as recited in claim 1 , wherein the support material has a water absorption exceeding 40%.
5. A catalyst as recited in claim 1 , wherein the support material has a surface area in the range of from 0.03 m 2 /g to 10 m 2 /g.
6. A catalyst as recited in claim 1 , wherein the support material has a water absorption in the range of from 42.5% to 80%, and a surface area in the range of from 0.5 m 2 /g to 5 m 2 /g.
7. A catalyst as recited in claim 1 , wherein the length-to-outside diameter ratio is in the range of from about 0.5 to about 1.6 and the ratio of internal diameter to outside diameter is in the range of from 0.01 to 0.25.
8. A catalyst as recited in claim 7 , wherein the length-to-outside diameter ratio is in the range of from about 0.9 to about 1.1 and the ratio of internal diameter to outside diameter is in the range of from 0.02 to 0.2.
9. A catalyst as recited in claim 1 , wherein the outside diameter is in the range of from 4 to 16 mm, and the bore diameter is smaller than 3.5 mm.
10. A catalyst as recited in claim 1 , wherein the outside diameter is in the range of from 5 to 12 mm, and the bore diameter is in the range of from 0.1 to 3 mm.
11. A catalyst as recited in claim 1 , wherein the bore diameter is in the range of from about 0.2 mm to about 2 mm.
12. A catalyst as recited in claim 1 , wherein the catalyst further comprises a promoter component comprising a rare earth metal, magnesium, rhenium, or an alkali metal.
13. A catalyst as recited in claim 1 , wherein the catalyst further comprises a promoter component comprising rhenium, an alkali metal selected from lithium, potassium, rubidium and cesium, and, in addition, a rhenium copromoter comprising sulfur, molybdenum, tungsten or chromium.
14. A method, comprising:
providing a shaped support material having a geometric configuration such that the length-to-outside diameter ratio is in the range of from about 0.3 to about 2 and the internal diameter is in the range upwardly to 30 percent of the outside diameter of said shaped catalyst support; and
depositing silver on the shaped support.
15. A method as recited in claim 14 , comprising depositing on the support, in addition to silver, a promoter component comprising rhenium, and a rhenium copromoter comprising sulfur, molybdenum, tungsten or chromium, wherein the rhenium copromoter is deposit prior to or simultaneous with the deposition of silver, and rhenium is deposited after at least a portion of the silver has been deposited.