# US 5,710,317 A · Preparation of difluoroacetic acid fluoride and difluoroacetic acid esters

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- Number: US 5,710,317 A
- Document ID: US5710317A
- Status: Granted
- Kind: A
- Application number: 08/506,730
- Filed: 1995-07-26
- Granted: 1998-01-20
- Earliest claimed: 1994-07-28
- Assignees: Asahi Glass Company, Limited
- Inventors: Kazuya Oharu; Seisaku Kumai
- Web page: https://patentgrep.com/patent/US5710317A

## CPC

- C07C 51/58: Preparation of carboxylic acid halides
- C07C 41/06: by addition of organic compounds only
- C07C 67/14: from carboxylic acid halides
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS

## Abstract

A method for preparing difluoroacetic acid fluoride, which comprises reacting a 1-alkoxy-1,1,2,2-tetrafluoroethane of the formula HCF.sub.2 CF.sub.2 OR.sup.1 wherein R.sup.1 is a C.sub.1-4 alkyl group in a gas phase in the presence of a metal oxide catalyst.

## Claims

### Claim 1

A method for preparing difluoroacetic acid fluoride, which comprises reacting a 1-alkoxy-1,1,2,2-tetrafluoroethane of the formula HCF.sub.2 CF.sub.2 OR.sup.1 wherein R.sup.1 is a C.sub.1-4 alkyl group in a gas phase in the presence of a metal oxide catalyst.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the metal oxide catalyst is at least one member selected from the group consisting of alumina, zirconia and titania.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the metal oxide catalyst is alumina.

### Claim 4 (depends on 1)

The method according to claim 1, wherein R.sup.1 is an ethyl group.

### Claim 5 (depends on 2)

The method according to claim 2, wherein R.sup.1 is an ethyl group.

### Claim 6 (depends on 3)

The method according to claim 3, wherein R.sup.I is an ethyl group.

### Claim 7

A method for preparing a difluoroacetic acid ester of the formula HCF.sub.2 COOR.sup.2 wherein R.sup.2 is a C.sub.1-4 alkyl group, which comprises reacting a 1-alkoxy-1,1,2,2-tetrafluoroethane of the formula HCF.sub.2 CF.sub.2 OR.sup.1 wherein R.sup.1 is a C.sub.1-4 alkyl group in a gas phase in the presence of a metal oxide catalyst to form difluoroacetic acid fluoride, and reacting the difluoroacetic acid fluoride with an alcohol of the formula R.sup.2 OH wherein R.sup.2 is as defined above.

### Claim 8 (depends on 7)

The method for preparing a difluoroacetic acid ester according to claim 7, wherein a tertiary amine is present together with the alcohol of the formula R.sup.2 OH.

### Claim 9 (depends on 7)

The method for preparing a difluoroacetic acid ester according to claim 7, wherein R.sup.2 is an ethyl group.

### Claim 10 (depends on 8)

The method for preparing a difluoroacetic acid ester according to claim 8, wherein R.sup.2 is an ethyl group.

### Claim 11 (depends on 7)

The method for preparing a difluoroacetic acid ester according to claim 7, wherein R.sup.1 and R.sup.2 are the same alkyl groups.

### Claim 12 (depends on 8)

The method for preparing a difluoroacetic acid ester according to claim 8, wherein R.sup.1 and R.sup.2 are the same alkyl groups.

### Claim 13 (depends on 9)

The method for preparing a difluoroacetic acid ester according to claim 9, wherein R.sup.1 and R.sup.2 are the same alkyl groups.

### Claim 14 (depends on 10)

The method for preparing a difluoroacetic acid ester according to claim 10, wherein R.sup.1 and R.sup.2 are the same alkyl groups.

### Claim 15

A method for producing a difluoroacetic acid ester containing substantially no alcohol, which comprises reacting a mixture of a difluoroacetic acid ester of the formula HCF.sub.2 COOR.sup.2 wherein R.sup.2 is a C.sub.1-4 alkyl group containing an alcohol of the formula R.sup.2 OH wherein R.sup.2 is as defined above with difluoroacetic acid fluoride.

### Claim 16 (depends on 15)

The method according to claim 15, wherein said reaction is carried out in the liquid phase at a temperature of from 0.degree. to 50.degree. C.

### Claim 17 (depends on 15)

The method of claim 15, wherein said reaction is carded out in the presence of an aprotic solvent.

### Claim 18 (depends on 15)

The method of claim 15, wherein said reaction is carried out in the presence of a tertiary amine.