Epoxidation process

• US 10,040,055 B2
• Filed: 06/02/2016
• Issued: 08/07/2018
• Est. Priority Date: 06/02/2015
• Status: Active Grant

• Current Assignee: Scientific Design Company, Inc. (Clariant AG)
• Original Assignee: Scientific Design Company, Inc. (Clariant AG)
• Inventors: Verrier, Christelle, Suchanek, Wojciech L.
• Primary Examiner(s): Nguyen, Cam N.
• Application Number:
  US15/579,419
• Publication Number:
  US 20180141025A1
• Time in Patent Office: 796 Days
• CPC Class Codes: B01J 19/0013 Controlling the temperature of the process
• CPC Class Codes: B01J 21/04 Alumina
• CPC Class Codes: B01J 2219/00051 Controlling the temperature
• CPC Class Codes: B01J 23/04 Alkali metals
• CPC Class Codes: B01J 23/36 Rhenium
• CPC Class Codes: B01J 23/50 Silver
• CPC Class Codes: B01J 35/56 Foraminous structures having flow-through passages or channels, e.g. grids or three-dimensional monoliths
• CPC Class Codes: B01J 35/612 less than 10 m2/g
• CPC Class Codes: B01J 35/633 less than 0.5 ml/g
• CPC Class Codes: B01J 35/635 0.5-1.0 ml/g
• CPC Class Codes: B01J 35/638 more than 1.0 ml/g
• CPC Class Codes: B01J 35/66 Pore distribution
• CPC Class Codes: B01J 37/0018 Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
• CPC Class Codes: B01J 37/086 Decomposition of an organometallic compound, a metal complex or a metal salt of a carboxylic acid
• CPC Class Codes: C04B 2111/0081 as catalysts or catalyst carriers
• CPC Class Codes: C04B 35/10 based on aluminium oxide
• CPC Class Codes: C04B 38/00 Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof treating slag with gases or gas generating material C04B5/06 ; expanded graphite C04B35/536
• CPC Class Codes: C04B 38/0096 Pores with coated inner walls
• CPC Class Codes: C04B 38/08 by adding porous substances
• CPC Class Codes: C04B 41/009 characterised by the material treated
• CPC Class Codes: C04B 41/4535 : applied as a solution, emulsion, dispersion or suspension
• CPC Class Codes: C04B 41/455 : the coating or impregnating process including a chemical conversion or reaction
• CPC Class Codes: C04B 41/5116 : Ag or Au
• CPC Class Codes: C04B 41/88 : Metals
• CPC Class Codes: C07D 301/10 : with catalysts containing silver or gold
• CPC Class Codes: C07D 301/22 : by oxidation of saturated compounds with air or molecular oxygen of mixtures of unsaturated and saturated compounds C07D301/04
• CPC Class Codes: Y02P 20/52 : using catalysts, e.g. selective catalysts

Abstract

A method is provided for improving the performance of a silver-based epoxidation catalyst comprising a carrier. The carrier includes at least 80 percent alpha alumina and has a pore volume from 0.3 mL/g to 1.2 mL/g, a surface area from 0.3 m²/g to 3.0 m²/g, and a pore architecture that provides at least one of a tortuosity of 7 or less, a constriction of 4 or less and a permeability of 30 mdarcys or greater. A catalytic amount of silver and a promoting amount of one or more promoters is disposed on and/or in said carrier. The method further includes the steps of initiating an epoxidation reaction by reacting a feed gas composition containing ethylene and oxygen present in a ratio of from about 3.5:1 to about 12:1, in the presence of the silver-based epoxidation catalyst at a temperature of about 200° C. to about 230° C., and subsequently increasing the temperature either stepwise or continuously.

Claims

1. A method of improving the performance of a silver-based epoxidation catalyst comprising a carrier comprising at least 80 percent alpha alumina and having a pore volume from 0.3 mL/g to 1.2 mL/g, a surface area from 0.3 m²/g to 3.0 m²/g, and a pore architecture that provides at least one of a tortuosity of 7 or less, a constriction of 4 or less and a permeability of 30 mdarcys or greater;

a catalytic amount of silver disposed on and/or in said carrier; and

a promoting amount of one or more promoters disposed on said carrier;

which method further comprises;

initiating an epoxidation reaction by reacting a feed gas composition containing ethylene and oxygen present in a ratio of from about 2.5;

1 to about 12;

1, in the presence of the silver-based epoxidation catalyst at a temperature of about 200°

C. to about 230°

C.; and

subsequently increasing the temperature either stepwise or continuously.

2. The method according to claim 1, wherein the subsequently increasing step is conducted stepwise.

3. The method according to claim 2, wherein each temperature step is held for a period of about 20 hours to about 100 hours.

4. The method according to claim 1, wherein the feed gas composition contains about 20 mol % to about 35 mol % ethylene, about 3 mol % to 8 mol % oxygen, and less than 2 mol % carbon dioxide.

5. The method according to claim 1, wherein said one or more promoters comprise Group 1 alkali metal promoters, one or more transition metals, one or more Group 2 alkaline earth metals or any combination thereof.

6. The method according to claim 1, wherein the subsequently increasing step comprises a stepwise temperature increase of about 5°

C. to about 10°

C. to a second temperature and maintained at the second temperature for about 25 hours to about 100 hours and then subsequently a stepwise increase of about 5°

C. to about 10°

C. to a third temperature and maintained at the third temperature for about 25 hours to about 100 hours.

7. The method according to claim 1, wherein the subsequently increasing step comprises increasing the temperature stepwise to one or more higher temperature steps with each temperature step being about 5°

C. to about 10°

C. than a previous temperature step.

8. The method according to claim 1, wherein said one or more transition metals comprise rhenium, molybdenum, tungsten, or any combination thereof.

9. The method according to claim 1, wherein said Group 1 alkali metal promoters are selected from the group consisting of cesium, lithium, sodium, potassium, and rubidium.

10. The method according to claim 1, wherein said one or more promoters comprises a promoting combination of rhenium, cesium and lithium.

11. The method according to claim 1, wherein said catalytic amount of silver is from 10 to 50% by weight.

12. The method according to claim 1, wherein said carrier has alumina crystallites having a platelet morphology in a content of less than 20 percent by volume.