JP4288451B2 - Process for producing 1,1,1,3,3,3-hexafluoropropan-2-ol - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention provides high purity 1,1,1,3,3,3-hexafluoropropan-2-ol (hereinafter abbreviated as “HFIP”) which is a useful compound as an intermediate for pharmaceuticals, agricultural chemicals and chemicals. Further, the present invention relates to a method for manufacturing at low cost.
[0002]
[Prior art and problems]
Since HFIP is used as an intermediate for pharmaceuticals and agricultural chemicals, especially an intermediate for anesthetics, it is desired to produce a high-purity product at low cost.
[0003]
On the other hand, as a method for producing HFIP by bringing hexafluoroacetone hydrate into contact with hydrogen in a liquid phase state and performing hydrogenation, for example, a reduction reaction using a palladium-carbon catalyst in Japanese Patent Publication No. 61-25694 In addition, JP-A-1-301631 discloses a reduction reaction using a palladium-alumina catalyst. However, HFIP obtained by these reactions is also described in JP-A-6-1884026. As shown in the figure, 1,1,1-trifluoroacetone (hereinafter abbreviated as “TFA”), which shows azeotropic behavior with HFIP, is included, and the recovery rate by distillation purification is low to obtain high purity HFIP. This is a factor that reduces productivity.
[0004]
An object of this invention is to provide the method of manufacturing HFIP highly purified and cheaply.
[0005]
[Means for Solving the Problems]
The present inventor has eagerly studied a catalyst with little by-product of TFA, which causes separation problems in hydrogenation in which hexafluoroacetone hydrate is brought into contact with hydrogen in a liquid phase. As a result, noble metal catalyst such as palladium black has been obtained. The inventors have found that it exhibits excellent selectivity, and have reached the present invention.
[0006]
That is, the present invention is characterized in that 1,1,1,3,3,3-hexafluoropropane is obtained by contacting hexafluoroacetone hydrate with hydrogen in the liquid phase in the presence of palladium black to perform hydrogenation. A method for producing -2-ol is provided.
[0007]
The present invention also provides hydrogenation by contacting hexafluoroacetone hydrate with hydrogen in the liquid phase in the presence of a noble metal catalyst to perform hydrogenation. A method for producing 1,1,1,3,3,3-hexafluoropropan-2-ol, wherein the selectivity of propan-2-ol is 99.9% or more.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hexafluoroacetone hydrate can be easily obtained by absorbing hexafluoroacetone in water, and has a general formula of (CF ₃ ) ₂ C (OH) ₂ .xH ₂ O (where x is 0 or more). As a stable form, a monohydrate of x = 0 (melting point: 46 ° C.) and a trihydrate of x = 2 (boiling point: 106 ° C.) are known as stable forms. Since the hydrate is uniformly mixed with water and exists in the form of an aqueous solution, hexafluoroacetone hydrate including the aqueous solution is represented by the above general formula.
[0009]
The water content of hexafluoroacetone hydrate used in this reaction is not particularly specified, but it is sufficient to use it in a liquid state of 2 to 10 hydrate, preferably a liquid of 2.5 to 4 hydrate. State. The aqueous solution corresponds to 2.5 to 4 hydrate.
[0010]
The noble metal catalyst used in the present invention is not particularly limited as long as it does not substantially produce TFA which is difficult to separate, but palladium black is particularly preferable.
[0011]
The amount of noble metal catalyst such as palladium black used in the present invention is not particularly limited, but 0.05 to 5% by weight of the amount calculated as a monohydrate of hexafluoroacetone hydrate is sufficient, preferably It is in the range of 0.1 to 2% by weight.
[0012]
Although the reaction temperature in the method of this invention is not specifically limited, Preferably it is 50-150 degreeC, More preferably, it is 60-100 degreeC.
[0013]
The hydrogen pressure used in the method of the present invention is not particularly limited, but is preferably 0.3 to 1.5 Mpa, more preferably 0.5 to 1 Mpa.
[0014]
In the present invention, the selectivity of HFIP may be determined by measuring the ratio of HFIP in the product by gas chromatography, preferably 99.9% or more, more preferably 99.95% or more, and still more preferably 99.99. % Or more, particularly 100%.
[0015]
【The invention's effect】
According to the production method of the present invention, when palladium black is used as a catalyst, TFA that is difficult to separate is not substantially generated, and thus high-purity HFIP can be easily obtained.
[0016]
【Example】
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated in detail, these do not limit this invention.
Example 1
60 g of hexafluoroacetone trihydrate was charged into a 200 ml autoclave equipped with a stirrer, and 360 mg (0.6 wt%) of palladium black was added.
[0017]
The inside of the container was replaced with hydrogen and heated to 100 ± 5 ° C. with a band heater.
[0018]
When the hydrogen pressure was kept at 0.7 MPa and stirring was started, hydrogen absorption started.
[0019]
After 7 hours, the heating and stirring was stopped, and the reaction solution was subjected to GC and NMR analysis. As a result, the reaction rate of hexafluoroacetone trihydrate was 97%, and the selectivity of HFIP was 99.95% by GC analysis. The product had a TFA of 0.05% and 1,1,1-trifluoroisopropanol of 0.00%.
(Example 2)
The reaction was performed in the same manner as in Example 1 except that the amount of palladium black used was 240 mg (0.4 wt%).
[0020]
As a result of GC and NMR analysis of the reaction solution, the reaction rate of hexafluoroacetone trihydrate was 68%, the selectivity of HFIP was 100.00% by GC analysis, and the by-product TFA was 0.00%. 1,1,1-trifluoroisopropanol was 0.00%.
(Example 3)
The reaction was performed in the same manner as in Example 1 except that the amount of palladium black used was 60 mg (0.1% by weight).
[0021]
As a result of GC and NMR analysis of the reaction solution, the reaction rate of hexafluoroacetone trihydrate was 14%, the selectivity of HFIP was 100.00% by GC analysis, and the by-product TFA was 0.00%. 1,1,1-trifluoroisopropanol was 0.00%.
(Comparative Example 1)
60 g of hexafluoroacetone trihydrate was charged into a 200 ml autoclave equipped with a stirrer, and 3 g (5 wt%) of 5% palladium-carbon was added.
[0022]
The inside of the container was replaced with hydrogen and heated to 70 ± 5 ° C. with a band heater.
[0023]
When the hydrogen pressure was kept at 0.7 MPa and stirring was started, hydrogen absorption started.
[0024]
After 5 hours, heating and stirring were stopped, and the reaction solution was analyzed by GC and NMR. As a result, the reaction rate of hexafluoroacetone trihydrate was 98%, and the selectivity of HFIP was 98.74% by GC analysis. The product had a TFA of 0.66% and 1,1,1-trifluoroisopropanol of 0.60%.
(Comparative Example 2)
60 g of hexafluoroacetone trihydrate was charged into a 200 ml autoclave equipped with a stirrer, and 3 g (5 wt%) of 5% palladium-alumina was added.
[0025]
The inside of the container was replaced with hydrogen and heated to 70 ± 5 ° C. with a band heater.
[0026]
When the hydrogen pressure was kept at 0.7 MPa and stirring was started, hydrogen absorption started.
[0027]
After 6 hours, heating and stirring were stopped, and the reaction solution was analyzed by GC and NMR. As a result, the reaction rate of hexafluoroacetone trihydrate was 87%, and the selectivity of HFIP was 99.22% by GC analysis. The product had a TFA of 0.78% and 1,1,1-trifluoroisopropanol of 0.00%.

Claims (1)

1,1,1,3,3,3-hexafluoropropan-2-ol, which is hydrogenated by contacting hexafluoroacetone hydrate with hydrogen in the presence of palladium black in a liquid phase. Production method.