# US 5,705,679 A · Honeycomb catalyst for vinyl acetate synthesis

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- Number: US 5,705,679 A
- Document ID: US5705679A
- Status: Granted
- Kind: A
- Application number: 08/627,960
- Filed: 1996-04-02
- Granted: 1998-01-06
- Earliest claimed: 1996-04-02
- Inventors: Ioan Nicolau; Philip M. Colling; Leland R. Johnson
- Web page: https://patentgrep.com/patent/US5705679A

## CPC

- B01J 37/0242: {Coating followed by impregnation}
- B01J 23/44: Palladium
- B01J 23/52: Gold
- B01J 23/58: with alkali- or alkaline earth metals
- B01J 23/66: Silver or gold
- B01J 35/57: Honeycombs
- C07C 67/055: in the presence of platinum group metals or their compounds
- B01J 21/08: Silica
- B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A catalyst particularly useful in the preparation of unsaturated esters such as the reaction of ethylene, oxygen and acetic acid in a vapor phase to form vinyl acetate. The catalyst comprises a honeycomb carrier coated with silica and containing palladium and gold throughout the silica coat. Such catalysts show reduced pressure drop and a high space time yield for vinyl acetate.

## Claims

### Claim 1

A method of preparing an unsaturated ester comprising reacting in a gas phase an olefin, an organic carboxylic acid and oxygen in the presence of a catalyst, the catalyst comprising a ceramic honeycomb carrier having-cells extending the entire length of the carrier, the carrier being provided with a silica coat within at least the cells, the catalyst further comprising palladium metal and gold metal distributed throughout the silica coat.

### Claim 2 (depends on 1)

The method of claim 1, wherein the olefin is ethylene.

### Claim 3 (depends on 2)

The method of claim 2, wherein a molar ratio of ethylene to oxygen is from about 80:20 to about 98:2.

### Claim 4 (depends on 1)

The method of claim 1, wherein the organic carboxylic acid is acetic acid.

### Claim 5 (depends on 4)

The method of claim 4, wherein a molar ratio of acetic acid to ethylene is from about 100:1 to about 1:100.

### Claim 6 (depends on 1)

The method of claim 1, wherein the unsaturated ester is prepared at a temperature of from about 150.degree. to about 220.degree. C.

### Claim 7 (depends on 1)

The method of claim 1, wherein the silica-coated cells of the catalyst carrier have a surface area of from about 50 m.sup.2 /g to about 500 m.sup.2 /g.

### Claim 8 (depends on 1)

The method of claim 1, wherein the catalyst carrier has a density of from 100 to 400 cells/in.sup.2.

### Claim 9 (depends on 1)

The method of claim 1, wherein the catalyst carrier has a density of from 200 to 400 cells/in.sup.2.

### Claim 10 (depends on 1)

The method of claim 1, wherein the silica coat comprises from about 15% to about 50% by weight of the catalyst.

### Claim 11 (depends on 1)

The method of claim 1, wherein the silica coat comprises from about 20% to about 40% by weight of the catalyst.

### Claim 12 (depends on 1)

The method of claim 1, wherein the reaction is carried out at a pressure of from about 1 to up to about 20 atmospheres gauge.

### Claim 13 (depends on 1)

The method of claim 1, wherein the amount of palladium metal comprises from about 1.5 gm/l to about 8.0 gm/l of the catalyst.

### Claim 14 (depends on 1)

The method of claim 1, wherein the amount of gold metal comprises from about 0.5 gm/l to about 8.0 gm/l of the catalyst.

### Claim 15 (depends on 1)

The method of claim 1, wherein the amount of gold metal in the catalyst comprises from about 6% to about 200% by weight relative to the amount of the palladium metal.

### Claim 16 (depends on 1)

The method of claim 1, wherein the cells comprise a tubular, square or a hexagonal shape.

### Claim 17 (depends on 1)

The method of claim 1, wherein said honeycomb carrier comprises cordierite, mullite or cordierite-mullite combination.