JPH08259477A - Production of 1,1,1,3,3-pentafluoropropene and production of 1,1,1,3,3-pentafluoropropane - Google Patents

Abstract

PURPOSE: To provide both a method for producing 1,1,1,3,3-pentafluoropropene and a method for producing 1,1,1,3,3-pentafluoropropane by using 1,1,1,3,3- pentafluoropropene as a raw material obtained by the method. CONSTITUTION: This method for producing 1,1,1,3,3-pentafluoropropene comprises reacting a 2-trifluoromethyl-3,3,3-trifluoropropionic acid ester with a metal salt in an aprotic solvent. 1,1,1,3,3-Pentafluoropropene obtained by the method is hydrogenated in the presence of a hydrogenating catalyst to give 1,1,1,3,3- pentafluoropropane to provide the objective method for producing 1,1,1,3,3- pentafluoropropane.

Description

Detailed Description of the Invention

[0001]

The present invention relates to 1,1,1,3,3-pentafluoropropane which is a useful compound which can be used as a substitute compound for CFC and HCFC used as a refrigerant, a foaming agent and a cleaning agent. A method for producing 1,1,1,3,3-pentafluoropropene useful as an intermediate for producing or a monomer of a fluorine-containing polymer, and the 1,1,1,
1,1, made from 3,3-pentafluoropropene
The present invention relates to a method for producing 1,3,3-pentafluoropropane.

[0002]

2. Description of the Related Art As a method for producing 1,1,1,3,3-pentafluoropropene, 2-trifluoromethyl-
A method is known in which an alkali metal salt of 3,3,3-trifluoropropionic acid is obtained by decarboxylation (Sy
ntheses of Fluoroorganic Compounds, Knunyants I.
L., Yakobuson GG, Springer-Verlag, 1985, 8-9
Pages, pages 53-54).

However, this method requires the use of highly toxic perfluoroisobutene in order to obtain the starting material, 2-trifluoromethyl-3,3,3-trifluoropropionic acid. Is difficult to implement.

Further, heptafluoroisobutenyl methyl ether obtained by dehydrogenating octafluoroisobutyl methyl ether, which is a methanol adduct of perfluoroisobutene, and concentrated hydrochloric acid are reacted in a water-soluble solvent to give 2-
A method for obtaining trifluoromethyl-3,3,3-trifluoropropionic acid (JP-A-63-35539) is also known. However, with this method, it is difficult to remove water from the carboxylic acid or the carboxylic acid alkali metal salt,
When the decarboxylation reaction is carried out while the water remains, the yield is remarkably reduced, which is not economical.

[0005]

An object of the present invention is to provide a method for producing 1,1,1,3,3-pentafluoropropene industrially efficiently and economically, and a method for producing the same. An object of the present invention is to provide a production method for economically obtaining 1,1,1,3,3-pentafluoropropane from the thus-obtained 1,1,1,3,3-pentafluoropropene as a raw material.

[0006]

The inventor of the present invention has
As a result of diligent examination of an industrial, efficient and economical production method of 1,3,3-pentafluoropropene,
When an easily available ester of 2-trifluoromethyl-3,3,3-trifluoropropionic acid is reacted with a metal salt in an aprotic solvent, 2-trifluoromethyl-3,3,3 is reacted in the reaction system. It was found that a metal salt of 3-trifluoropropionic acid is produced, and further a decarboxylation reaction proceeds in the system to produce 1,1,1,3,3-pentafluoropropene all at once. Completed

That is, according to the present invention, an ester of 2-trifluoromethyl-3,3,3-trifluoropropionic acid is reacted with a metal salt in an aprotic solvent to give 1,1,1.
1,1,3,3-Pentafluoropropene is obtained, 1,1,
The present invention relates to a method for producing 1,3,3-pentafluoropropene.

Taking the reaction of methyl 2-trifluoromethyl-3,3,3-trifluoropropionate and sodium iodide as an example, the reaction in the present invention is considered to proceed as follows.

(CF ₃ ) ₂ CHCOOMe + NaI →
(CF ₃ ) ₂ CHCOONa + MeI (CF ₃ ) ₂ CHCOONa → CF ₃ CH = CF ₂ + N
aF

In this reaction, by reacting methyl 2-trifluoromethyl-3,3,3-trifluoropropionate with sodium iodide, sodium 2-trifluoromethyl-3,3,3-trifluoropropionate is obtained. And methyl iodide is produced. In fact, the production of methyl iodide has been confirmed in this reaction. 2 generated in the reaction system
-Metal salts such as sodium trifluoromethyl-3,3,3-trifluoropropionate are more easily decarboxylated as compared with ordinary hydrocarbon-based carboxylic acid salts, and immediately decarboxylated at the reaction temperature. , 1,1,3,3-Pentafluoropropene.

2-trifluoromethyl-in the present invention
Examples of 3,3,3-trifluoropropionic acid esters include esters with alcohols having 1 to 10 carbon atoms such as methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, and isobutyl ester. Particularly preferred is methyl ester.

As the metal salt, halides,
Cyanide, thiolate or mercaptide, alcoholate and the like can be mentioned.

The salt of this metal is reacted with the ester of 2-trifluoromethyl-3,3,3-trifluoropropionic acid, usually in at least stoichiometric amounts.

As the above-mentioned halide, LiF, Li
Cl, LiBr, LiI, NaCl, NaBr, Na
I, CaCl ₂ , CaBr ₂ , and CaI ₂ , and other examples include Cs salt and Rb salt. However, from the economical viewpoint, Li salt, Na salt, and Ca salt are preferable, and Na salt is more preferable.

The cyanide may be NaC.
N, KCN, etc. are mentioned.

The above thiol salt (mercaptide)
Examples thereof include mercaptans obtained from mercaptans having 1 to 4 carbon atoms or thiophenol and having Li, Na and K as cations.

Further, examples of the alcoholate include alcoholates obtained from alcohols having 1 to 6 carbon atoms such as tert-butyl alcohol and having Li, Na and K as cations.

As the aprotic solvent usable in the present invention, amides such as N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolidone and hexamethylphosphoric triamide; dimethyl sulfoxide, sulfolane Such as sulfoxides; ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and other glymes; ethyl acetate, butyl acetate, and other esters; acetone, methyl ethyl ketone, and other ketones; acetonitrile, benzonitrile, and other nitriles; To be

The reaction temperature in the present invention may be varied depending on the solvent used, but is usually in the range of 30 to 180 ° C, preferably 40 to 160 ° C.

If necessary, crown ether,
A phase transfer catalyst such as a quaternary ammonium salt may be used.

An ester of 2-trifluoromethyl-3,3,3-trifluoropropionic acid, which is a starting material for the reaction in the present invention, such as 2-trifluoromethyl-3,
Methyl 3,3-trifluoropropionate can be easily obtained by reacting octafluoroisobutyl methyl ether, which is a methanol adduct of perfluoroisobutene, with sulfuric acid (Syntheses of Fluoroorg).
anic Compounds, Knunyants IL, Yakobuson GG,
Springer-Verlag, 1985, p. 65).

The present invention also uses 1,1,1,3,3-pentafluoropropene obtained by the above method according to the present invention (first invention) as a raw material, and hydrogenates it in the presence of a hydrogenation catalyst. The present invention also provides a method for producing 1,1,1,3,3-pentafluoropropane.

In this hydrogenation reaction, the reaction product containing 1,1,1,3,3-pentafluoropropene obtained by the first invention is used as it is, or it is separated by commonly known rectification. It is possible to use it after purifying 1,1,1,3,3-pentafluoropropene.

The reaction product obtained by the first invention includes
In addition to 1,1,1,3,3-pentafluoropropene, carbon dioxide, 1,1,1,3,3,3-hexafluoropropane, and in some cases alkyl halides such as methyl chloride and methyl iodide Including, but these are
Since it does not affect the subsequent hydrogenation reaction,
It is possible to use 1,3,3-pentafluoropropene as it is without separation, or if desired, it may be purified and separated before use.

The reaction is carried out in the liquid phase,
It is possible to carry out the reaction in the gas phase, it is also possible to use a solvent in the liquid phase, and in the gas phase reaction, a system such as a fixed bed type gas phase reaction or a fluidized bed type gas phase reaction can be adopted.

The hydrogenation catalyst is preferably a noble metal catalyst, and examples thereof include palladium, platinum and rhodium catalysts.
Particularly, a palladium catalyst is preferable.

The hydrogenation catalyst is preferably supported on a carrier, such as activated carbon, alumina, silica gel, titanium oxide,
Zirconia and other carriers can be used, but those supported on activated carbon are preferred.

Further, the particle size of the carrier has almost no effect on the reaction, and when the hydrogenation reaction is carried out in the liquid phase, it is powdery, while when the hydrogenation reaction is carried out in the gas phase, it is from 0.1 to Ten
0 mm is suitable.

A wide range of supported concentrations of 0.05 to 10% by weight can be used, but 0.5 to 5% by weight is usually recommended.

The reaction temperature is usually -20 to 300 ° C, preferably -20 to 200 ° C. In the case of gas phase reaction, by-products are formed when the reaction is carried out at 300 ° C or higher.

In the hydrogenation reaction of 1,1,1,3,3-pentafluoropropene in the gas phase, the ratio of hydrogen to the raw material can be varied greatly. However, hydrogenation is usually carried out using at least a stoichiometric amount of hydrogen. It is possible to use considerably more than stoichiometric amounts of hydrogen, based on the total moles of starting material, for example 3 times the molar amount or more.

The reaction pressure is not particularly limited, and it can be carried out under pressure, under reduced pressure, or under normal pressure. However, since the apparatus becomes complicated under reduced pressure, it is preferable to carry out the reaction under pressure or under normal pressure.

The contact time is usually 0.1 to 300 seconds, especially 1
~ 30 seconds.

In the hydrogenation reaction of 1,1,1,3,3-pentafluoropropene in the liquid phase, the reaction is continued until the consumption of hydrogen by the reaction is completed. The reaction is under pressure,
Especially, it can be performed within a pressure range of 1 to ²⁰ kg / cm ² G.

In the liquid phase hydrogenation reaction, the catalyst can be reused after the reaction product is recovered after the reaction is completed.

[0036]

According to the present invention, an ester of 2-trifluoromethyl-3,3,3-trifluoropropionic acid is reacted with a metal salt in an aprotic solvent to give 1,1,1.
1,3,3-pentafluoropropene is obtained, and the 1,1,1,3,3-pentafluoropropene is hydrogenated in the presence of a hydrogenation catalyst to give 1,1,1,3,3-pentafluoropropene. Since fluoropropane is obtained, 2-
A metal salt of trifluoromethyl-3,3,3-trifluoropropionic acid is produced, and further, a decarboxylation reaction proceeds in the system, and 1,1,1,3,3-pentafluoropropene is produced all at once. However, the target product can be produced efficiently and economically using easily available raw materials, and useful 1,1,1,3,3-pentafluoropropane can be produced economically.

[0037]

The present invention will be described in more detail with reference to the following examples.

Example 1 N- in a 100 ml four-necked flask equipped with a dropping funnel.
7.5 g (0.05 mol) of sodium iodide was dissolved in 50 ml of methylpyrrolidone and heated to 110 ° C.

While maintaining the temperature, from the dropping funnel,
10.5 g (0.05 mol) of methyl hexafluoroisobutyrate
It dripped over time. The low boiling point gas generated during this reaction was extracted from the upper part of the flask and collected in a receiver cooled with dry ice-acetone.

The amount of collected gas was 10.2 g, and the target 5FH (1,1,1,3,3-pentafluoropropene) and 236fa (1,1,1,3,3,3-hexafluoro) were used. It was a mixture of propane) and methyl iodide.
Analysis of the respective mixing ratios by gas chromatography revealed that the weight ratio of 5FH: 236fa: methyl iodide was 52.
It was 4: 3.7: 43.9, and the yield of 5FH was 81%.

Example 2 In the same reactor as in Example 1, 3.0 g (0.05 mol) of sodium chloride was suspended in 50 ml of N-methylpyrrolidone and heated to 140 ° C.

While maintaining the temperature, from the dropping funnel,
Methyl hexafluoroisobutyrate 10.5 g (0.05 mol)
It was added dropwise over 1.5 hours. The low boiling point gas generated during the reaction was extracted from the upper part of the flask and collected in a receiver cooled with dry ice-acetone.

The amount of collected gas was 7.2 g, which was a desired mixture of 5FH, 236fa, and methyl chloride. Gas chromatographic analysis of the respective mixing ratios revealed that the weight ratio of 5FH: 236fa: methyl chloride was 10.
It was 1: 61.4: 28.5, and the yield of 5FH was 11%.

Example 3 7.5 g (0.05 mol) of sodium iodide was dissolved in 50 ml of acetone and refluxed in a 100 ml four-necked flask equipped with a dropping funnel and a condenser.

While refluxing, 10.5 g (0.05 mol) of methyl hexafluoroisobutyrate was added dropwise from the dropping funnel over 3 hours. The low boiling point gas generated during the reaction was extracted from the upper part of the cooling tube and collected in a receiver cooled with dry ice-acetone.

The amount of collected gas was 7.1 g, which was a target mixture of 5FH, 236fa, and methyl iodide. Gas chromatographic analysis of the respective mixing ratios revealed that the weight ratio of 5FH: 236fa: methyl iodide was 3
It was 8.4: 33.4: 28.2, and the yield of 5FH was 41%.

Example 4 In the same reactor as in Example 1, 3.0 g (0.05 mol) of sodium iodide was dissolved in 50 ml of triethylene glycol dimethyl ether and heated to 120 ° C.

While maintaining the temperature, from the dropping funnel,
2 parts of methyl hexafluoroisobutyrate 10.5 g (0.05 mol)
It dripped over time. The low boiling point gas generated during the reaction was extracted from the upper part of the flask and collected in a receiver cooled with dry ice-acetone.

The collected gas was 9.2 g, which was a target mixture of 5FH, 236fa, and methyl iodide. Gas chromatographic analysis of the respective mixing ratios revealed that the weight ratio of 5FH: 236fa: methyl iodide was 5
The ratio was 5.0: 5.8: 39.2, and the yield of 5FH was 77%.

Example 5 50 ml of N-methylpyrrolidone was added to the same reactor as in Example 1.
Suspend 11.0 g (0.1 mol) of calcium chloride to give 140
Heated to ° C. While maintaining the temperature, add 10.5 g (0.05 mol) of methyl hexafluoroisobutyrate from the dropping funnel.
It was added dropwise over 1.5 hours. The low boiling point gas generated during the reaction was extracted from the upper part of the flask and collected in a receiver cooled with dry ice-acetone.

The gas collected was 7.8 g, which was the desired mixture of 5FH, 236fa, and methyl chloride. Analysis of the respective mixing ratios by gas chromatography revealed that the weight ratio of 5FH: 236fa: methyl chloride was 27.
It was 1: 46.7: 26.2, and the yield of 5FH was 32%.

Example 6 Palladium catalyst 2.3 cc supported on activated carbon at a concentration of 0.5% by weight in a SUS316 reaction tube having an inner diameter of 7 mm and a length of 150 mm
Was charged and heated to 100 ° C. in an electric furnace while flowing nitrogen gas, and after reaching a predetermined temperature, rectification (after using the 15-stage Oldershaw type rectification column was obtained in Example 1) 1, 1,1,3,3-pentafluoropropene and hydrogen were introduced at a rate of 5.5 cc / min and 14.5 cc / min, respectively. The reaction temperature was kept at 100 ° C.

The produced gas was washed with water and then analyzed by gas chromatography. The conversion rate of 1,1,1,3,3-pentafluoropropene is almost 100%.
Selectivity of 1,3,3-pentafluoropropane is 99.5%
Met.

Example 7 The same reactor as in Example 6 was charged with 2.3 cc of a palladium catalyst supported on activated carbon at a concentration of 0.5% by weight, and heated to 50 ° C. in an electric furnace while flowing nitrogen gas, to a predetermined temperature. 1,1, which was obtained in Example 1 and then separated by rectification (using a 15-stage Oldershaw type rectification column) 1,1,
1,3,3-Pentafluoropropene was introduced at a rate of 5.5 cc / min, and hydrogen was introduced at a rate of 14.5 cc / min. The reaction temperature was 50 ° C.

The produced gas was washed with water and then analyzed by gas chromatography. The conversion rate of 1,1,1,3,3-pentafluoropropene is almost 100%.
Selectivity of 1,3,3-pentafluoropropane is 99.6%
Met.

Example 8 The same reactor as in Example 6 was charged with 1.9 cc of a palladium catalyst supported on alumina at a concentration of 0.5% by weight, and the temperature was raised to room temperature (23 ° C.) while flowing nitrogen gas. Fractionation after obtaining in 1 (using 15-stage Oldershaw type rectification tower)
1,1,1,3,3-pentafluoropropene separated by the above method was introduced at a rate of 5.5 cc / min, and hydrogen was introduced at a rate of 14.5 cc / min. The reaction temperature was 23 ° C.

The produced gas was washed with water and analyzed by gas chromatography. The target 1,1,1,3,3-pentafluoropropane was obtained with a reaction rate of 75.3% and a selectivity of 99.7%.

Example 9 The same reactor as in Example 6 was charged with 2.3 cc of a palladium catalyst supported on activated carbon at a concentration of 2% by weight, and heated to 50 ° C. in an electric furnace while flowing nitrogen gas, to a predetermined temperature. After reaching the temperature of, carbon dioxide (10 wt%), 1,1,1,3,3,3
A mixed gas of the reaction product of the example consisting of 3-hexafluoropropane (2% by weight), methyl iodide (0.3% by weight) and 1,1,1,3,3-pentafluoropropene (87.7% by weight) was used. Hydrogen was introduced at a rate of 5.5 cc / min and hydrogen at a rate of 14.5 cc / min. The reaction temperature was 50 ° C.

The produced gas was washed with water and then analyzed by gas chromatography. The reaction proceeded without any problems,
The conversion rate of 1,1,1,3,3-pentafluoropropene in the mixed gas is almost 100%.
The selectivity from pentafluoropropene to 1,1,1,3,3-pentafluoropropane was 99.6%.

Example 10 The same reactor as in Example 6 was charged with 2.3 cc of a palladium catalyst supported on activated carbon at a concentration of 2% by weight, and heated to 50 ° C. in an electric furnace while flowing a nitrogen gas to a predetermined temperature. After reaching the temperature of, carbon dioxide (5% by weight), 1,1,1,3,3,3
A mixed gas of the reaction product of Example 2 consisting of 3-hexafluoropropane (11% by weight), methyl chloride (25% by weight) and 1,1,1,3,3-pentafluoropropene (57% by weight) was added. Hydrogen was introduced at a rate of 5.5 cc / min and hydrogen at a rate of 14.5 cc / min. The reaction temperature was 50 ° C.

The produced gas was washed with water and then analyzed by gas chromatography. The reaction proceeded without any problems,
The conversion rate of 1,1,1,3,3-pentafluoropropene in the mixed gas is almost 100%.
-The selectivity from pentafluoropropene to 1,1,1,3,3-pentafluoropropane was 99.4%.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location C07C 19/08 C07C 19/08 // C07B 61/00 300 C07B 61/00 300

Claims (14)

[Claims] 1. 2-Trifluoromethyl-3,3,3-
Reaction of an ester of trifluoropropionic acid with a salt of a metal in an aprotic solvent to give 1,1,1,3,3-pentafluoropropene, which is 1,1,1,3,3-pentafluoropropene Production method. 2. 2-trifluoromethyl-3,3,3-
The ester of trifluoropropionic acid has 1 to 10 carbon atoms.
The method according to claim 1, which is an ester of the alcohol with. 3. The metal salt is a metal halide, cyanide, thiolate or alcoholate of a metal.
The method described in. 4. A metal salt is treated with 2-trifluoromethyl-
The method according to claim 1, wherein at least a stoichiometric amount is used with respect to the ester of 3,3,3-trifluoropropionic acid. 5. The method according to claim 1, wherein the aprotic solvent is an amide, a sulfoxide, a glyme, an ester, a ketone or a nitrile. 6. The method according to claim 1, wherein the reaction is carried out in the temperature range of 30 to 180 ° C. 7. 1,1,1,3,3-Pentafluoropropene obtained by the method according to any one of claims 1 to 5 is hydrogenated in the presence of a hydrogenation catalyst to give 1,1. ，
Obtain 1,3,3-pentafluoropropane, 1,1,
A method for producing 1,3,3-pentafluoropropane. 8. The method according to claim 7, wherein 1,1,1,3,3-pentafluoropropene is hydrogenated as it is or after being purified. 9. The method according to claim 7, wherein the hydrogenation reaction is carried out in a gas phase or a liquid phase. 10. The method according to claim 7, wherein hydrogen is used in at least a stoichiometric amount. 11. A noble metal catalyst is used as the hydrogenation catalyst,
The method according to claim 7. 12. The loading concentration of the hydrogenation catalyst on each type of carrier is set to 0.
The method according to claim 11, wherein the amount is 05 to 10% by weight. 13. The reaction is carried out in the temperature range of −20 to 300 ° C.
The method according to claim 7. 14. The method according to claim 7, wherein the reaction is carried out under pressure.