α,α-difluoroacetaldehyde production method

Patent metadata

Field	Value
Publication number	US-9440900-B2
Application number	US-201414761774-A
Country	US
Kind code	B2
Filing date	Jan 23, 2014
Priority date	Jan 25, 2013
Publication date	Sep 13, 2016
Grant date	Sep 13, 2016

Abstract

A production method of α,α-difluoroacetaldehyde according to the present invention includes reaction of an α,α-difluoroacetic acid ester with hydrogen gas (H 2 ) in the presence of a ruthenium catalyst. It is possible to selectively obtain α,α-difluoroacetaldehyde as a partially reduced product of the hydrogenation reaction by the adoption of specific reaction conditions (in particular, reaction solvent and reaction temperature). This hydrogenation process can be alternative to the industrially unpractical hydride reduction process.

First claim

The invention claimed is:

1. A method for producing α,α-difluoroacetaldehyde of the formula [3], comprising: reaction of α,α-difluoroacetic acid ester of the general formula [1] with hydrogen gas (H s ) in the presence of a ruthenium complex of the general formula [2]

where R 1 represents an alkyl group or a substituted alkyl group;

where R each independently represents a hydrogen atom, an alkyl group, a substituted alkyl group, an aromatic ring group or a substituted aromatic ring group; Ar each independently represents an aromatic ring group or a substituted aromatic ring group; X each independently represents a ligand with a formal charge of −1 or 0, wherein the sum of the formal charges of three X is −2; and n each independently represents an integer of 1 or 2.

2. The method according to claim 1 , wherein the reaction is performed in the presence of a base.

3. The method according to claim 2 , wherein the ruthenium complex is a ruthenium complex of the general formula [4]

where Ph represents a phenyl group.

4. The method according to claim 1 , wherein the α,α-difluoroacetic acid ester of the general formula [1] is an α,α-difluoroacetic acid ester of the general formula [5],

where R 2 is an alkyl group.

5. The method according to claim 1 , wherein the reaction is performed at a reaction temperature of 30° C. or lower with the use of an alcohol solvent as a reaction solvent.

6. The method according to claim 4 , wherein the reaction is performed at a reaction temperature of 20° C. or lower with the use of an alcohol solvent as a reaction solvent.

7. The method according to claim 1 , wherein the reaction is performed at a reaction temperature of 50° C. or lower with the use of an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, a halogenated solvent or an ether solvent as a reaction solvent.

8. The method according to claim 7 , wherein the reaction is performed at a reaction temperature of 40° C. or lower with the use of an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, a halogenated solvent or an ether solvent as a reaction solvent.

9. The method according to claim 1 , comprising:
stopping the reaction at the time when the selectivity of the α,α-difluoroacetaldehyde of the formula [3] and β,β-difluoroethanol is α,α-difluoroacetaldehyde:β,β-difluoroethanol=90 or more:10 or less; and
recovering and recycling unreacted α,α-difluoroacetic acid ester.

10. The method according to claim 1 , further comprising post-treatment to, when the α,α-difluoroacetaldehyde is obtained as a stable equivalent of the general formula [6] or [7], purify the α,α-difluoroacetaldehyde as a hemiacetal of the general formula [8] by contact of the stable equivalent with methanol or ethanol,

where R 3 represents a methyl group or an ethyl group,

where R 4 represents a methyl group or an ethyl group,

11. A method for producing α,α-difluoroacetaldehyde of the formula [3], comprising: reaction of an α,α-difluoroacetic acid ester of the general formula [1] with hydrogen gas (H 2 ) in the presence of a ruthenium complex of the general formula [4],

where R 1 represents an alkyl group or a substituted alkyl group,

where Ph represents a phenyl group.

12. The method according to claim 11 , wherein the reaction is performed in the presence of a base.

13. The method according to claim 11 , wherein the reaction is performed at a reaction temperature of 30° C. or lower with the use of an alcohol solvent as a reaction solvent.

14. The method according to claim 13 , wherein the reaction is performed at a reaction temperature of 20° C. or lower with the use of an alcohol solvent as a reaction solvent.

15. The method according to claim 11 , wherein the reaction is performed at a reaction temperature of 50° C. or lower with the use of an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, a halogenated solvent or an ether solvent as a reaction solvent.

16. The method according to claim 15 , wherein the reaction is performed at a reaction temperature of 40° C. or lower with the use of an aliphatic hydrocarbon solvent, an aromatic hydrocarbon solvent, a halogenated solvent or an ether solvent as a reaction solvent.

17. The method according to claim 11 , comprising:
stopping the reaction at the time when the selectivity of the α,α-difluoroacetaldehyde of the formula [3] and β,β-difluoroethanol is α,α-difluoroacetaldehyde:β,β-difluoroethanol=90 or more:10 or less; and
recovering and recycling unreacted α,α-difluoroacetic acid ester.

18. The method according to claim 11 , further comprising post-treatment to, when the α,α-difluoroacetaldehyde is obtained as a stable equivalent of the general formula [6] or [7], purify the α,α-difluoroacetaldehyde as a hemiacetal of the general formula [8] by contact of the stable equivalent with methanol or ethanol,

where R 3 represents a methyl group or an ethyl group,

where R 4 represents a methyl group or an ethyl group,

Assignees

• Central Glass Co Ltd

Inventors

• Ootsuka Takashi
• Imamura Mari
• Ishii Akihiro
• Ueda Koji
• Mimura Shunsuke

Classifications

• C07C45/41 Primary

  by hydrogenolysis or reduction of carboxylic groups or functional derivatives thereof · CPC title

• Y02P20/582

  Recycling of unreacted starting or intermediate materials · CPC title

• C07C47/14

  containing halogen · CPC title