Process for the production of an olefin oxide
View Patent ↗The invention provides a process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin and oxygen in the presence of a catalyst comprising a carrier and silver deposited on the carrier, which carrier comprises at least 85 weight percent α-alumina and has a surface area of at least 1.3 m 2 /g, a median pore diameter of more than 0.8 μm, and a pore size distribution wherein at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm.
1. A process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin and oxygen in the presence of a catalyst comprising a carrier and silver deposited on the carrier, which carrier comprises at least 85 weight percent α-alumina and has a surface area of at least 1.3 m 2 /g, a median pore diameter of more than 0.8 μm, and a pore size distribution wherein at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm.
2. A process as claimed in claim 1 , wherein the olefin is ethylene.
3. A process as claimed in claim 1 , wherein the feed further comprises a reaction modifier selected from the group consisting of organic halides, organic nitrogen compounds, nitrogen oxides, hydrazine, hydroxylamine and ammonia.
4. A process as claimed in claim 1 , wherein the feed additionally comprises carbon dioxide in a concentration of above 1 mole percent, relative to the total feed.
5. A process as claimed in claim 1 , wherein the feed additionally comprises carbon dioxide in a concentration of 1 mole percent or lower, relative to the total feed.
6. A process as claimed in claim 1 , wherein an olefin oxide is formed at a work rate in the range of from 0.5 to 10 kmole olefin oxide per m 3 of catalyst per hour.
7. A process as claimed in claim 1 wherein the carrier has a pore size distribution such that at least 90% of the total pore volume is contained in the pores with diameters in the range of from 0.1 to 10 μm; at least 90% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm; the pores with diameters greater than 10 μm represent less than 10% of the total pore volume; and the pores with diameters less than 0.3 μm represent less than 10% of the total pore volume.
8. A process as claimed in claim 7 wherein the pores with diameters greater than 10 μm represent at most 8% of the total pore volume; and the pores with diameters less than 0.3 μm represent at most 3% of the total pore volume.
9. A process as claimed in claim 1 wherein the carrier has a median pore diameter of at most 2 μm, a total pore volume in the range of from 0.25 to 0.8 ml/g and a surface area of at most 5 m 2 /g, a total pore volume in the range of from 0.3 to 0.7 ml/g and a surface area in the range of from 1.3 to 3 m 2 /g.
10. A process as claimed in claim 1 wherein the carrier has a total pore volume of at most 0.6 ml/g.
11. A process as claimed in claim 1 wherein the carrier comprises at least 95 weight percent α-alumina and the carrier has a median pore diameter in the range of from 0.9 to 1.8 μm, a water absorption in the range of from 0.3 to 0.7 g/g and a surface area in the range of from 1.4 m 2 /g to 2.5 m 2 /g.
12. A process as claimed in claim 1 wherein the carrier has a water absorption of at most 0.6 g/g.
13. A process as claimed in claim 1 wherein silver is deposited on the carrier in a quantity of from 10 to 500 g/kg, relative to the weight of the catalyst.
14. A process as claimed in claim 1 wherein the carrier comprises alumina and a bond material.
15. A process as claimed in claim 14 wherein the carrier has an α-alumina content of at least 95 weight percent, and wherein the bond material comprises an alkaline earth metal silicate bond material.
16. A process as claimed in claim 15 wherein the bond material further comprises one or more additional components selected from the group consisting of a hydrated alumina, a zirconium component and a titanium component.
17. A process as claimed in claim 1 which comprises, deposited on the carrier in addition to silver, one or more further elements selected from the group consisting of nitrogen, sulfur, phosphorus, boron, fluorine, Group IA metals, Group IIA metals, rhenium, molybdenum, tungsten, chromium, titanium, hafnium, zirconium, vanadium, manganese, thallium, thorium, tantalum, niobium, gallium and germanium and mixtures thereof.
18. A process as claimed in claim 17 wherein the Group IA metals are selected from the group consisting of lithium, potassium, rubidium and cesium.
19. A process as claimed in claim 1 which comprises, deposited on the carrier in addition to silver, one or more of rhenium, molybdenum, tungsten, Group IA metals, and nitrate- or nitrite-forming compounds.
20. A process as claimed in claim 1 which comprises rhenium deposited on the carrier in addition to silver, and optionally a rhenium co-promoter selected from the group consisting of sulfur, phosphorus, boron, and compounds thereof.
21. A process as claimed in claim 1 wherein the carrier has a pore size distribution such that at least 75%, the pore volume contained in pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.4 to 10 μm.
22. A process as claimed in claim 1 wherein the carrier has a pore size distribution such that the pores with diameters in the range of from 0.1 to 10 μm represent more than 90% of the total pore volume and at least 15% of the pore volume contained in pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 5 to 10 μm.
23. A process as claimed in claim 1 wherein the carrier is in the form of formed bodies fired at a temperature of at least 1250° C.
24. A process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin and oxygen in the presence of a catalyst comprising a carrier and silver deposited on the carrier, which carrier comprises a bond material and at least 85 weight percent α-alumina, and has a surface area of at least 1 m 2 /g, a median pore diameter of more than 0.8 μm, and a pore size distribution wherein at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm.
25. A process as claimed in claim 24 wherein the surface area is at least 1.3 m 2 /g.
26. A process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin and oxygen in the presence of a catalyst comprising a carrier and silver deposited on the carrier, which carrier is in the form of formed bodies fired at a temperature of at least 1250° C. comprising at least 85 weight percent α-alumina, and has a surface area of at least 1 m 2 /g, a median pore diameter of more than 0.8 μm, and a pore size distribution wherein at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm.
27. A process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin and oxygen in the presence of a catalyst comprising a carrier and silver deposited on the carrier, which carrier comprises at least 85 weight percent α-alumina and has a non-platelet morphology, a surface area of at least 1 m 2 /g, a median pore diameter of more than 0.8 μm, and a pore size distribution wherein at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm.
28. A process for the epoxidation of an olefin, which process comprises reacting a feed comprising an olefin and oxygen in the presence of a catalyst comprising a carrier and silver deposited on the carrier, which carrier has a surface area of at least 1 m 2 /g, a water absorption of at most 0.6 g/g, a median pore diameter of more than 0.8 μm, and a pore size distribution wherein at least 80% of the total pore volume is contained in pores with diameters in the range of from 0.1 to 10 μm and at least 80% of the pore volume contained in the pores with diameters in the range of from 0.1 to 10 μm is contained in pores with diameters in the range of from 0.3 to 10 μm.