Nanometer scale restructuring of alumina carrier surface and catalysts for the production of alkene oxides

• US 20060252643A1
• Filed: 05/09/2005
• Published: 11/09/2006
• Est. Priority Date: 05/09/2005
• Status: Active Grant

• Current Assignee: SD Lizenzverwertungsgesellschaft mbH & Co. KG
• Original Assignee: Scientific Design Company, Inc. (Clariant AG)
• Inventors: Pak, Serguei
• Granted Patent: US 7,507,844 B2
• Time in Patent Office: Days
• US Class Current: 502/439
• CPC Class Codes: B01J 21/04 Alumina
• CPC Class Codes: B01J 23/50 Silver
• CPC Class Codes: B01J 23/66 Silver or gold
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/50 characterised by their shape or configuration
• CPC Class Codes: B01J 37/06 Washing B01J37/0009, B01J37/0018 take precedence
• CPC Class Codes: B01J 38/60 using acids
• CPC Class Codes: B01J 38/64 using alkaline material; using salts
• CPC Class Codes: C07D 301/10 with catalysts containing silver or gold
• CPC Class Codes: Y02P 20/584 Recycling of catalysts

Abstract

A carrier and a catalyst useful for the oxidation of ethylene to ethylene oxide which uses the carrier. The carrier is composed of an inert, refractory solid support such as alpha alumina and has a surface exhibiting a plurality of nanometer scale protrusions projecting outwardly from the surface, and has a catalytically effective amount of silver thereon.

Claims

1. A carrier for a catalyst useful for the epoxidation of an olefin which comprises an inert, refractory solid support, the support having a surface and a plurality of protrusions projecting outwardly from the surface of the support, which protrusions are present at a frequencies in a range of from about 250 cycles/micrometer or more.

2. The carrier of claim 1 wherein the support comprises aluminum oxide, charcoal, pumice, magnesia, zirconia, titania, kieselguhr, fuller'"'"'s earth, silicon carbide, silica, silicon dioxide, magnesia, clays, artificial zeolites, natural zeolites, ceramics and combination thereof.

3. The carrier of claim 1 wherein the protrusions are in the shape of rods, tubes, fibers, or combinations thereof.

4. The carrier of claim 1 wherein the protrusions have an average diameter in the range of from about 1 nm to about 100 nm.

5. The carrier of claim 1 wherein the protrusions have an average height in the range of from about 1 nm to about 300 nm.

6. The carrier of claim 1 wherein the protrusions are present on the surface of the support at a frequency in the range from about 250 to about 800 cycles/micrometer as measured by power spectral density analysis.

7. A process for producing a carrier for a catalyst useful for the epoxidation of an olefin which comprises providing an inert, refractory solid support, the support having a surface, and treating a surface of the support to thereby provide a plurality of protrusions projecting outwardly from the surface of the support, which protrusions are present at a frequencies in a range of from about 250 cycles/micrometer or more.

8. The process of claim 7 wherein the protrusions are in the shape of rods, tubes, fibers, or combinations thereof.

9. The process of claim 7 wherein the protrusions have an average diameter in the range of from about 1 nm to about 100 nm.

10. The process of claim 7 wherein the protrusions have an average height in the range of from about 1 nm to about 300 nm.

11. The process of claim 7 wherein the protrusions are present on the surface of the support at a frequency in the range from about 250 to about 800 cycles/micrometer as measured by power spectral density analysis.

12. The process of claim 7 wherein the treating is conducted by soaking the support in a solution of an organic acid, an inorganic acid, a base, a salt, or combinations thereof for a time and at temperature sufficient to dissolve a portion of the support and redeposit the dissolved portion back onto the surface of the support.

13. The process of claim 7 wherein the treating is conducted by soaking the support in a solution of an alkali hydroxide, or HNO₃.

14. The process of claim 7 wherein the treating is conducted by soaking the support in an aqueous solution of an alkali hydroxide, or HNO₃ at a concentration in the range of from about 0.01 molar to about 10 molar.

15. The process of claim 7 wherein the treating is conducted by soaking the support in an aqueous solution of an alkali hydroxide, or HNO₃ at a concentration in the range of from about 0.01 molar to about 10 molar for from about 1 minute to about 30 days at a temperature of from about 0°

C. to about 250°

C., with optional subsequent drying.

16. A catalyst useful for the epoxidation of an olefin which comprises a carrier which comprises an inert, refractory solid support, the support having a surface and a plurality of protrusions projecting outwardly from the surface, which protrusions are present at a frequencies in a range of from about 250 cycles/micrometer or more;

the carrier comprising a catalytically effective amount of silver thereon.

17. The catalyst of claim 16 further comprising a promoting amount of a promoter thereon, the promoter comprising one or more of an alkali metal containing compounds, one or more transition metal containing compounds, one or more sulfur components, one or more fluorine containing components, or combinations thereof.

18. The catalyst of claim 16 wherein the transition metal comprises an element selected from Groups 5b, 6b, 7b and 8 of the Periodic Table of the Elements, and combinations thereof.

19. The catalyst of claim 16 wherein the transition metal comprises rhenium, molybdenum, tungsten or combinations thereof.

20. The catalyst of claim 16 wherein the alkali metal containing compound comprises lithium, sodium, potassium, rubidium, cesium or combinations thereof.

21. A process for the oxidation of ethylene to ethylene oxide which comprises the vapor phase oxidation of ethylene with molecular oxygen in a fixed bed, tubular reactor, in the presence of the catalyst of claim 16.