Method for producing α,α-difluoroacetaldehyde

Patent metadata

Field	Value
Publication number	US-10351502-B2
Application number	US-201616071829-A
Country	US
Kind code	B2
Filing date	Dec 1, 2016
Priority date	Jan 21, 2016
Publication date	Jul 16, 2019
Grant date	Jul 16, 2019

Abstract

Disclosed is an industrial method for efficient production of an α,α-difluoroaldehyde compound, which includes reaction of an α,α-difluoroacetate with hydrogen gas (H 2 ) in the presence of a ruthenium catalyst and a base. By the adoption of specific reaction conditions (catalyst, base, pressure etc.), it is possible to produce the target α,α-difluoroaldehyde compound with a high conversion rate and high selectivity.

First claim

The invention claimed is:

1. A method for producing an α,α-difluoroacetaldehyde of the formula [3] or α,α-difluoroacetaldehyde alkyl hemiacetal of the general formula [4], comprising reaction of an α,α-difluoroacetate of the general formula [1] with hydrogen in the presence of a ruthenium complex of the formula [2] and a base,

in which R 1 represents an alkyl group or substituted alkyl group,

in which Ph represents a phenyl group,

in which R 2 has the same meaning as R 1 in the general formula [1],
wherein the reaction is performed under conditions that:
the base is an alkali metal alkoxide and is used in an amount of 0.001 mol or more per 1 mol of the α,α-difluoroacetate; and
a pressure the hydrogen used is 1.0 MPa to 10 MPa in terms of absolute pressure,
whereby a rate of conversion of the α,α-difluoroacetate during the reaction is 80% or higher; and a selectivity of the α,α-difluoroacetaldehyde or α,α-difluoroacetaldehyde alkyl hemiacetal formed from the α,α-difluoroacetate to β,β-difluoroethanol formed as a by-product during the reaction is in a range of α,α-difluoroacetaldehyde or α,α-difluoroacetaldehyde alkyl hemiacetal:β,β-difluoroethanol=90% or higher:10% or lower.

2. The method according to claim 1 , wherein the alkali metal alkoxide is lithium methoxide, sodium methoxide, potassium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, lithium isopropoxide, sodium isopropoxide, potassium isopropoxide, lithium tert-butoxide, sodium tert-butoxide or potassium tert-butoxide.

3. The method according to claim 2 , wherein the alkali metal alkoxide is lithium methoxide, sodium methoxide, potassium methoxide, lithium ethoxide, sodium ethoxide or potassium ethoxide.

4. The method according to claim 1 ,
wherein the α,α-difluoroacetate of the general formula [1] is ethyl α,α-difluoroacetate
wherein the α,α-difluoroacetaldehyde alkyl hemiacetal of the general formula [4] is α,α-difluoroacetaldehyde ethyl hemiacetal,
wherein the base is sodium ethoxide and is used in an amount of 0.01 to 5.0 mol per 1 mol of the ethyl α,α-difluoroacetate;
wherein the pressure of the hydrogen used is 2.0 MPa to 6.0 MPa in terms of absolute pressure,
wherein the rate of conversion of the ethyl α,α-difluoroacetate during the reaction is 90% or higher; and
wherein the selectivity of the α,α-difluoroacetaldehyde or α,α-difluoroacetaldehyde ethyl hemiacetal formed from the ethyl α,α-difluoroacetate to β,β-difluoroethanol formed as a byproduct during the reaction is in a range of α,α-difluoroacetaldehyde or α,α-difluoroacetaldehyde ethyl hemiacetal:β,β-difluoroethanol=93% or higher:7% or less.

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

Assignees

• Central Glass Co Ltd

Inventors

• Inazu Asami
• Nishizawa Eri
• Akiba Shinya
• Nadano Ryo

Classifications

• C07B61/00

  Other general methods · CPC title

• C07C47/14

  containing halogen · CPC title

• C07C43/317

  having [IMAGE cpc-sch-C07C-0961.gif] groups, X being hydrogen or metal · CPC title

• B01J31/24

  Phosphines {, i.e. phosphorus bonded to only carbon atoms, or to both carbon and hydrogen atoms, including e.g. sp2-hybridised phosphorus compounds such as phosphabenzene, phosphole or anionic phospholide ligands} · CPC title

• B01J2523/821

  Ruthenium · CPC title