# US 5,705,661 A · Catalyst for production of ethylene oxide

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- Number: US 5,705,661 A
- Document ID: US5705661A
- Status: Granted
- Kind: A
- Application number: 08/716,890
- Filed: 1996-09-20
- Granted: 1998-01-06
- Earliest claimed: 1995-09-25
- Assignees: Mitsubishi Chemical Corporation
- Inventors: Tomoatsu Iwakura; Takako Imamoto; Katsumi Nakashiro
- Web page: https://patentgrep.com/patent/US5705661A

## CPC

- B01J 23/66: Silver or gold
- B01J 23/688: {with manganese, technetium or rhenium}
- B01J 35/60: characterised by their surface properties or porosity
- B01J 37/0205: {in several steps}
- C07D 301/10: with catalysts containing silver or gold
- B01J 21/04: Alumina
- B01J 21/12: Silica and alumina
- B01J 35/612: {less than 10 m2/g}
- B01J 35/633: {less than 0.5 ml/g}
- Y02P 20/52: using catalysts, e.g. selective catalysts
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07D: HETEROCYCLIC COMPOUNDS (macromolecular compounds C08)
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

A catalyst for oxidizing ethylene and producing ethylene oxide, said catalyst being prepared by pretreating a porous carrier with a solution containing a lithium compound and a cesium compound, thereafter, impregnating a solution containing a silver compound and a cesium compound in the pretreated porous carrier and then heat-treating the impregnated porous carrier. The use of the catalyst of this invention provides high selectivity in the production of ethylene oxide by the vapor contact oxidation of ethylene.

## Claims

### Claim 1

A catalyst for oxidizing ethylene and producing ethylene oxide, said catalyst being prepared by pretreating a porous carrier with a solution containing a lithium compound and a cesium compound, thereafter, impregnating a solution containing a silver compound and a cesium compound in the pretreated porous carrier and then heat-treating the impregnated porous carrier.

### Claim 2 (depends on 1)

A catalyst according to claim 1, wherein said catalyst contains silver of 5 to 30% by weight.

### Claim 3 (depends on 1)

A catalyst according to claim 1, wherein said catalyst contains lithium of 100 to 2000 ppm and cesium of 250 to 2000 ppm.

### Claim 4 (depends on 1)

A catalyst according to claim 1, wherein a weight ratio (Li/Cs) of lithium to cesium is in a range of 0.1:1 to 4:1.

### Claim 5 (depends on 1)

A catalyst according to claim 1, wherein 10 to 80% of the total cesium to be impregnated in said porous carrier is impregnated at the same time as said lithium compound.

### Claim 6 (depends on 1)

A catalyst according to claim 1, wherein said carrier has a surface area in a range of 0.6 to 5 m.sup.2 /g.

### Claim 7 (depends on 1)

A catalyst according to claim 1, wherein a main component of said carrier is .alpha.-alumina.

### Claim 8 (depends on 1)

A catalyst according to claim 1, wherein said lithium compound is lithium carbonate or lithium bicarbonate.

### Claim 9 (depends on 1)

A catalyst according to claim 1, wherein said lithium compound is lithium carboxylate.

### Claim 10 (depends on 1)

A catalyst according to claim 1, wherein said pretreatment comprises the steps of impregnating a solution containing a lithium compound and a cesium compound in said porous carrier and then heat-treating the impregnated porous carrier.

### Claim 11 (depends on 10)

A catalyst according to claim 10, wherein superheated steam is employed to perform the heat treatment in said pretreatment.

### Claim 12 (depends on 1)

A catalyst according to claim 1, wherein said silver compound and said cesium compound are both impregnated by using an aqueous solution containing a silver compound, a cesium compound, and amine as a complex forming agent.

### Claim 13 (depends on 1)

A catalyst according to claim 1, wherein superheated steam is employed to perform said step of impregnating a silver compound and a cesium compound in the porous carrier and then heat-treating the impregnated porous carrier.

### Claim 14 (depends on 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)

A process for producing ethylene oxide wherein ethylene is subjected to vapor contact oxidation with molecular oxygen in the presence of the catalyst according to any of claims 1 to 13.