# US 4,391,735 A · Cleaning and regenerating ethylene oxide catalysts

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- Number: US 4,391,735 A
- Document ID: US4391735A
- Status: Granted
- Kind: A
- Application number: 06/284,207
- Filed: 1981-07-17
- Granted: 1983-07-05
- Earliest claimed: 1981-07-17
- Assignees: InterNorth, Inc.
- Inventors: Paul J. Busse
- Web page: https://patentgrep.com/patent/US4391735A

## CPC

- B01J 23/96: of catalysts comprising metals, oxides or hydroxides of the noble metals
- B01J 23/66: Silver or gold
- B01J 38/62: organic
- C07D 301/10: with catalysts containing silver or gold
- Y02P 20/584: Recycling of 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 composition and method for removing alkali metal-containing impurities from supported silver catalysts wherein the composition is comprised of an inert organic liquid and a solubilizing agent. The method is used prior to regeneration of the catalyst with cesium, rubidium, or mixtures thereof to improve the selectivity of the regenerated catalyst.

## Claims

### Claim 1

A method for removing alkali metal-containing impurities from supported silver catalysts which have been used for the direct oxidation of ethylene to ethylene oxide which comprises washing the catalyst with a composition which is comprised of in inert organic liquid and about 0.1% to about 10%, by weight, of solubilizing agent which is selected from the group consisting of aliphatic and aromatic acids.

### Claim 2 (depends on 1)

The method of claim 1 wherein the inert organic liquid is selected from the group consisting of aliphatic, alicyclic, and aromatic hydrocarbons, ethers, alcohols, and ketones, and aliphatic and aromatic esters, amines, amides, aldehydes, and nitriles.

### Claim 3 (depends on 2)

The method of claim 2 wherein the concentration of the solubilizing agent is from about 0.1% to about 5%.

### Claim 4 (depends on 3)

The method of claim 3 wherein the washing procedure is carried out from 1 to 25 times.

### Claim 5 (depends on 1)

The method of claim 1 wherein the solubilizing agent is selected from the group consisting of acetic acid, propionic acid, lactic acid, and salicylic acid.

### Claim 6

A method of regenerating a supported silver catalyst which has been used for the direct oxidation of ethylene to ethylene oxide which comprises washing the catalyst to remove alkali metal-containing impurities with a composition comprised of an inert organic liquid and about 0.1% to about 10%, by weight, of a solubilizing agent which is selected from the group consisting of aliphatic and aromatic acids, and then applying to the catalyst from 1 to 1000 parts per 1 million parts of catalyst of cesium, rubidium, or a mixture thereof.

### Claim 7 (depends on 6)

The method of claim 6 wherein the inert organic liquid is selected from the group consisting of aliphatic, alicyclic, and aromatic hydrocarbons, ethers, alcohols, and ketones, and aliphatic and aromatic esters, amides, aldehydes, and nitriles.

### Claim 8 (depends on 7)

The method of claim 7 wherein the concentration of the solubilizing agent is from about 0.1% to about 5%.

### Claim 9 (depends on 8)

The method of claim 8 wherein the washing procedure is carried out from 1 to 25 times.

### Claim 10 (depends on 6)

The method of claim 6 wherein the solubilizing agent is selected from the group consisting of acetic acid, propionic acid, lactic acid, and salicylic acid.

### Claim 11

In a method for regenerating a supported silver catalyst which has been used for the direct oxidation of ethylene to ethylene oxide which comprises washing the catalyst with an inert organic liquid and then applying to the catalyst from 1 to 1000 parts per 1 million parts of catalyst of cesium, rubidium, or a mixture thereof, the improvement which comprises removing alkali metal-containing impurities by including about 0.1% to about 10% by weight, of a solubilizing agent in the inert organic liquid, said solubilizing agent selected from the group consisting of aliphatic and aromatic acids.

### Claim 12 (depends on 11)

The method of claim 11 wherein the inert organic liquid is selected from the group consisting of aliphatic, alicyclic, and aromatic hydrocarbons, ethers, alcohols, and ketones, and aliphatic and aromatic esters, amides, aldehydes, and nitriles.

### Claim 13 (depends on 12)

The method of claim 12 wherein the concentration of the solubilizing agent is from about 0.1% to about 5%.

### Claim 14 (depends on 13)

The method of claim 13 wherein the washing procedure is carried out from 1 to 25 times.

### Claim 15 (depends on 11)

The method of claim 11 wherein the solubilizing agent is selected from the group consisting of acetic acid, propionic acid, lactic acid, and salicylic acid.