JP2657792B2 - Method for producing fluorinated ether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a fluorinated ether.

[0002]

2. Description of the Related Art Various methods have been proposed for producing fluorine-containing ethers. For example, according to German Patent Publication No. 1294949, the following general formula: (In the formula, n represents an integer of 0 to 6) as a raw material, which is prepared in an aprotic polar organic solvent such as dimethylformamide, diglycoldimethylether, or dimethylsulfoxide. There has been proposed a method of reacting with an alkylating agent such as a dialkyl sulfate or an alkyl halide in the presence of potassium fluoride. However, in this case,
Since the reaction raw material is very expensive perfluoroacyl fluoride, the production cost of the desired fluorinated ether is increased, and this perfluoroacyl fluoride absorbs moisture in the atmosphere. Since it generates highly toxic hydrogen fluoride, it involves safety issues, and because of its high volatility, its handling is difficult.Especially, it is necessary to increase the reaction pressure during the reaction. It included some problems.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a fluorine-containing ether which is inexpensive, has high safety and is less volatile than perfluoroacyl fluoride as a reaction raw material. It is an object of the present invention to provide a method for efficiently manufacturing the same.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention. That is, according to the present invention, the following general formula _{^{(1) R 1 CF 2 OR}} 2 (1) ( wherein, R ¹ represents a perfluoro lower alkyl group, R ²
Represents an aliphatic group) in the production of a fluorine-containing ether represented by the following general formula (2) R ¹ COCl (2) (wherein R ¹ has the same meaning as described above) in an aprotic polar solvent. A) an alkylating agent having an aliphatic group R ² and potassium fluoride, wherein the potassium fluoride has a specific surface area of at least 1 m ² / g or more. And a use ratio of the potassium fluoride is at least 2 mol per 1 mol of the perfluoroacyl chloride.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized in that perfluoroacyl chloride represented by the general formula (2) is used as a reaction raw material. In the general formula (2), the perfluoro-lower alkyl group represented by R ¹ has 1 to 7, preferably 2 to 6 carbon atoms.
The carbon number of the aliphatic group represented by R ² is not particularly limited, but is usually 1 to 18, preferably 1 to 6, and more preferably 1 to 4. The aliphatic group includes a linear, branched or cyclic saturated or unsaturated alkyl group. These aliphatic groups include halogens (Cl, Br, F
And the like, or a lower alkoxy group having a lower alkyl group having 1 to 7 carbon atoms, preferably 1 to 3 carbon atoms;
It may have a substituent such as a lower alkylcarbonyloxy group and a lower alkyloxycarbonyl group.

The perfluoroacyl chloride used as a reaction raw material in the present invention is extremely inexpensive when compared with the corresponding perfluoroacyl fluoride,
The gas generated when reacting with moisture in the atmosphere is hydrogen chloride, which is less toxic than hydrogen fluoride, so it is very excellent in terms of safety, and its boiling point is extremely high. It has advantages such as excellent handleability and low reaction pressure.

In order to produce the fluorinated ether of the present invention, the perfluoroacyl chloride, the alkylating agent and potassium fluoride are reacted in an aprotic polar organic solvent. The alkylating agent in this case has an aliphatic group corresponding to the aliphatic group R ² in the general formula (1), and is chlorinated (R ² -Cl) or brominated (R ^2-
Br) sulfate (R ² O—SO ₂ —OR) (wherein R
² and R represent an aliphatic group), and the like. Specific examples of these alkylating agents include dialkyl sulfate, alkyl paratoluenesulfonate, alkyl-trifluoromethanesulfonate, alkyl trifluoromethanesulfonate (triflate), and alkyl methanesulfonate (mesylate). These alkylating agents are described in detail in German Patent Publication No. 1294949.

The potassium fluoride used in the present invention is in the form of fine particles having a specific surface area of at least 1 m ² / g (BET method) or more, preferably 1.5 m ² / g or more. Is usually about 2 m ² / g.
The average particle size is 10 to 50 μm, and the water content is usually 0.3% by weight or less. Its bulk specific gravity is usually 0.7 g / ml or less, preferably 0.5 g / ml or less, and its lower limit is about 0.3 g / ml.
Such potassium fluoride can be obtained by spray drying a solution containing a precipitate of potassium fluoride by a spray drying method. Potassium fluoride having a small specific surface area obtained by filtering and drying a precipitate of potassium fluoride which has been generally used in the past cannot obtain a fluorine-containing ether in good yield.

As the aprotic polar organic solvent, various conventionally known solvents are used. Examples of such solvents include monoglyme, diglyme, triglyme, tetraglyme, diethyl ether, dibutyl ether, dioxane and the like. , Nitriles such as acetonitrile, chain amides such as dimethylformamide and dimethylacetamide, or 1,3-dimethyl-2-
Cyclic amides such as imidazolidinone and N-methyl-2-pyrrolidone;

The use ratio of potassium fluoride is at least 2 moles, preferably 2.2 moles or more, more preferably 2.5 to 3.5 moles, per mole of perfluoroacyl chloride as a reaction raw material. The upper limit is about 5 mol. If the use ratio of potassium fluoride is less than the above range, the desired fluorinated ether cannot be obtained in good yield. The proportion of the alkylating agent to be used is not particularly limited as long as it is 1 mol or more per 1 mol of perfluoroacyl chloride, and preferably 1 to 2 mol. Although the usage ratio of the organic solvent is not particularly limited, it is preferably 2 to 4 parts by weight based on 1 part by weight of perfluoroacyl chloride.

The reaction temperature varies depending on the amount of the catalyst, the type of the organic solvent, the type of the alkylating agent and the like.
° C, preferably 50 to 150 ° C. The reaction pressure is not particularly limited, and any pressure from a normal pressure to a pressurized system can be used, but from the viewpoint of operability and the like, normal pressure to 20 kg / cm ² G
The use of a pressure of is preferred.

[0012]

Next, the present invention will be described in more detail with reference to examples.

Example 1 A 1500 ml stainless steel synthesis kettle equipped with a pressure gauge, a thermometer, a stirrer, a gas inlet tube and a gas outlet tube was charged with 201 g (0.86 mol) of heptafluorobutyryl chloride.
l), 150 g of spray-dried potassium fluoride (2.
59 mol) and 132 g (1.05 mol) of dimethyl sulfate
l) and 600 g of dried diglyme as a solvent
l and sealed. Thereafter, the synthesis kettle was heated to a temperature of 80-85 ° C. and maintained at a stirring speed of 300 RPM. After heating starts,
After about one hour, heat generation in the synthesis kettle was observed, and the temperature inside the kettle rose from 85 to 100 ° C. This heat generation also subsided after a while, and a decrease in the pressure inside the synthesis pot was gradually observed. When the reaction was carried out while maintaining the reaction temperature at 80 ° C., no pressure drop was observed after about 10 hours, indicating a constant pressure. The reaction product was withdrawn from the synthesis vessel by depressurizing the inside of the synthesis vessel and collecting the vapor that had been distilled out by heating at the outlet using a trap.
As a result, 184 g of a colorless transparent liquid was obtained. This was subjected to atmospheric distillation to obtain a desired fluorinated ether (1,1,2,2,3,3,3) as a fraction having a boiling point of 60 ° C.
4,4,4-Nonafluorobutyl-methyl ether (C
₄ F ₉ OCH ₃ ) was obtained.

The properties of the spray-dried potassium fluoride (Morita Chemical Industries, Ltd.) are as follows. (1) Appearance: fine white powder (2) Moisture: 0.3% by weight or less (Karl-Fischer method) (3) Particle size: 10-50 μm (4) Specific surface area: 1-2 m ² / g (BET method)

Example 2 201 g (0.86 mol) of heptafluorobutyryl chloride was placed in a 1500 ml stainless steel synthesis kettle equipped with a pressure gauge, a thermometer, a stirrer, a gas inlet tube and a gas outlet tube.
l), 150 g of spray-dried potassium fluoride (2.
59 mol) and 132 g (1.05 mol) of dimethyl sulfate
1) and, as a solvent, dried 1,3-dimethyl-2
-500 ml of imidazolidinone was added and sealed under atmospheric pressure. Thereafter, stirring was started and the reaction temperature was increased to 50, 60, 7
The temperature was gradually increased to 0 ° C., and the reaction was carried out at about 80 ° C. As the temperature rose, the pressure of the system also increased, and when the temperature was 80 ° C., it rose to 3.9 kg / cm ² G. After that, the pressure of the system gradually decreased at a constant reaction temperature and continued for 10 hours. Later, it showed a constant pressure of 1.4 kg / cm ² G at 80 ° C. The reaction was carried out for 12 hours, after which the reaction temperature was returned to room temperature, and the reaction product was withdrawn from the synthesis vessel. The reaction product was extracted from the synthesis kettle by heating the inside of the synthesis kettle under reduced pressure, and cooling and collecting the distilled steam at the outlet using a trap. as a result,
202 g of a colorless transparent liquid was obtained. The reaction mixture contained a small amount of heptafluoropropyl methyl ester (crude yield: 17%). Crude yield of C ₄ F ₉ OCH ₃ : 69% (based on acyl chloride as raw material) Thereafter, purification was carried out using an atmospheric distillation column, and the desired fluorinated ether (C ₄ F) was obtained as a fraction having a boiling point of 60 ° C. ₉ OCH
₃ ) Got it. Isolation yield of C ₄ F ₉ OCH ₃ : 54% (based on starting material acyl chloride)

[0016]

According to the present invention, a fluorinated ether can be produced with good yield and safety from perfluoroacyl chloride as a raw material. The fluorinated ether obtained by the present invention has low toxicity, is chemically and thermally stable, and does not contain chlorine atoms, so that it can destroy the ozone layer in the stratosphere even if released into the atmosphere. There is no. The fluorinated ether according to the present invention has a high detergency and is widely used as a substitute for a conventional chlorofluorocarbon in the field of metal surface cleaning agents and the like.

Continuing on the front page (72) Inventor Naoto Takada 6th floor of Hongo Sonoyama Building, 2-22-3 Hongo, Bunkyo-ku, Tokyo New Refrigerant, etc. Project Room (72) Inventor Etsuo Fujimoto Bunkyo, Tokyo 2-22 Hongo Ward, Hongo Sonoyama Building 6F, New Refrigerant Project Room (72) Inventor Akira Sekiya 1-1-1 Higashi, Tsukuba, Ibaraki Pref. Examiner Toshiro Fujimori (56) References JP-A-8-34755 (JP, A)

Claims (1)

(57) [Claims] 1. A following general formula _{^{(1) R 1 CF 2 OR}} 2 (1) ( wherein, R ¹ represents a perfluoro lower alkyl group, R ²
Represents an aliphatic group) in the production of a fluorine-containing ether represented by the following general formula (2) R ¹ COCl (2) (wherein R ¹ has the same meaning as described above) in an aprotic polar solvent. A) an alkylating agent having an aliphatic group R ² and potassium fluoride, wherein the potassium fluoride has a specific surface area of at least 1 m ² / g or more. Wherein the potassium fluoride is used at a rate of at least 2 moles per 1 mole of the perfluoroacyl chloride.