JP3030335B2 - Purification method of fluorinated ether - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying a fluorine-containing ether.

[0002]

2. Description of the Related Art Various methods have been proposed for producing fluorine-containing ethers. For example, German Patent Publication No. 1294949, Japanese Patent Publication No. 2627406,
There is a method disclosed in Japanese Patent Application Laid-Open No. 9-40594. However, these conventional methods produce a large amount of a fluorinated ester as a by-product. The present inventors comprise a first reaction step of reacting a perfluoroacyl halide with an alkali metal fluoride in the presence of an aprotic organic solvent, and a second step of reacting the obtained reaction product with an alkylating agent. A method for producing a fluorinated ether was previously proposed. However, even with this improved method, several percent of a fluorine-containing ester is formed, and it is difficult to efficiently separate the fluorine-containing ester even by using a distillation column having 50 theoretical plates.
Similarly, when a fluorinated ether is used as a solvent or a solvent, if a fluorinated ester is mixed in, it is difficult to separate and purify by ordinary distillation.

[0003]

An object of the present invention is to provide a method for separating a fluorine-containing ester which is an impurity without decomposing a fluorine-containing ether.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, when an alkaline aqueous solution is brought into contact with a fluorinated ether containing a fluorinated ester as an impurity, the fluorinated ether is converted to Without decomposing, only the ester, which is an impurity, decomposed, and the decomposed product moved to the aqueous phase, and was found to be efficiently separated only by liquid separation, thereby completing the present invention. That is, according to the present invention,
The following general formula (1)

Embedded image In the fluorine-containing ether in the fluorine-containing ether represented
On the other hand, the following general formula (2) contained at a ratio of 0.5 to 5 mol%

Embedded image In the method for separating a fluorine-containing ester represented by the fluorine-containing ether from the fluorine-containing ether, the fluorine-containing ether containing the fluorine-containing ester is brought into contact with an alkaline aqueous solution to decompose the fluorine-containing ester, A purification method is provided.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The fluorine-containing ether used as a raw material to be treated in the present invention contains a fluorine-containing ester as an impurity. In this case, the fluorinated ether is a compound represented by the general formula (1),
On the other hand, the fluorinated ester as the impurity is a compound represented by the general formula (2). The mixing ratio of the fluorinated ester is 0.5 to 5 mol% with respect to the fluorinated ether,
In particular, it is 0.5 to 3 mol%. The fluorinated ether containing the fluorinated ester as an impurity is produced by the above-mentioned conventionally known various methods, or preferably produced by the two-step method previously proposed by the present inventors. This two-step method is used for producing the fluorinated ether represented by the general formula (1),

Embedded image A first reaction step of reacting a perfluoroacyl halide represented by the formula with an alkali metal fluoride in an aprotic polar organic solvent, and a second reaction step of reacting an alkylating agent with the obtained reaction product. It is. In the general formulas (1) to (3), Rf ¹ is a linear or branched saturated or unsaturated perfluoroalkyl group, and has 1 to 7, preferably 2 to 6 carbon atoms. .
In the general formula (1) or (2), R ² is an alkyl group having 1 to 4 carbon atoms. The alkyl group includes a linear or branched alkyl group. The alkyl group is a halogen (Cl, Br, F, etc.)
And may have a substituent such as a lower alkoxy group having a lower alkyl group having 1 to 3 carbon atoms, a lower alkylcarbonyloxy group, a lower alkyloxycarbonyl group, or the like. In the general formula (3), X represents a halogen. Halogen includes chlorine, bromine and fluorine.

The following are specific examples of the perfluoroacyl halide. CF ₃ COF, C ₂ F ₅ COF, C ₃ F ₇ COF, C ₄ F ₉ C
OF, C ₅ F ₁₁ COF, (CF ₃ ) ₂ CFCOF, (C
F ₃ ) ₂ CFCF ₂ COF, (CF ₃ ) ₂ CFC ₂ F ₄ CO
F, (CF ₃ ) ₃ C-COF, (CF ₃ ) ₃ C-CF ₂ CO
F, (CF ₃ ) ₃ C—C ₂ F ₄ COF, C ₆ H ₁₁ COF, C
F ₃ COCl, C ₂ F ₅ COCl, C ₃ F ₇ COCl, C ₄ F
₉ COCl, C ₅ F ₁₁ COCl, (CF ₃ ) ₂ CFCOC
1, (CF ₃ ) ₂ CFCF ₂ COCl, (CF ₃ ) ₂ CFC ₂
F ₄ COCl, (CF ₃ ) ₃ C—COCl, (CF ₃ ) ₃ C
—CF ₂ COCl, (CF ₃ ) ₃ C—C ₂ F ₄ COCl,
_{(CF 3) 3 C-C} 3 F 6 COCl, C 6 F 11 COCl like.

The alkali metal fluoride includes sodium fluoride, potassium fluoride, lithium fluoride and cesium fluoride. The use of potassium fluoride is preferred. As the potassium fluoride, it is particularly preferable to use 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. In this case, the upper limit of the specific surface area is usually 2 m ²
/ G, its average particle size is 10 to 50 µm, and its 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.
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.

The alkylating agent has an alkyl group corresponding to the alkyl group R ² in the general formula (1), and includes a chlorinated product (R ² —Cl) and a brominated product (R ² —B
r), a sulfate (R ² O—SO ₂ —OR) (wherein R
Represents 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 aprotic polar organic solvent includes:
Conventionally known various things are used, such as, for example, monoglyme, diglyme, triglyme, tetraglyme, diethyl ether, dibutyl ether, ethers such as dioxane, nitriles such as acetonitrile, dimethylformamide, dimethyl Chain amides such as acetamide or 1,3-dimethyl-2-
Cyclic amides such as imidazolidinone and N-methyl-2-pyrrolidone;

[0010] The method for producing the above-mentioned fluorinated ether includes the following steps.
It is carried out by two reaction steps including a reaction step and a second reaction step. Hereinafter, these reaction steps will be described in detail. (First Reaction Step) This first reaction step is a step in which perfluoroacyl halide is reacted with an alkali metal fluoride in the presence of an aprotic polar organic solvent as a reaction solvent to produce perfluoroalcoholate. is there. The reaction in this case is represented by the following equation.

Embedded image The ratio of alkali metal fluoride (MF), when used perfluoroacyl fluoride (Rf ¹ COF) as perfluoro acyl halide (Rf ¹ COX), ¹ mol per of Rf ¹ COF, 1 to 4 mol, Preferably 1 to
3 moles. When a raw material (Rf ¹ COX, X: Cl or Br) other than perfluoroacyl fluoride is used, 2 to 5 mol, preferably 2 to 4 mol, per mol thereof is used.
It is a mole ratio. The proportion of the reaction solvent used is not particularly limited, but is preferably 2 to 4 parts by weight per 1 part by weight of the perfluoroacyl halide. The reaction temperature is
Usually, it is 30 to 200 ° C, preferably 50 to 150 ° C. The reaction pressure is not particularly limited, and it can be used at any pressure from a normal pressure to a pressurized system.However, from the viewpoint of increasing the yield of the obtained acyl halide fluoride and suppressing by-products, the reaction pressure is from normal pressure to The use of a pressure of 3 kg / cm ² G is preferred.
This first reaction step is preferably carried out by gradually dropping perfluoroacyl halide into a reaction solvent containing an alkali metal fluoride.

(Second Reaction Step) This second reaction step is a step of reacting the product obtained in the first reaction step with an alkylating agent to produce a fluorinated ether. The reaction in this case is represented by the following equation.

Embedded image The ratio of the alkylating agent (R ² Y) used is 1 to 4 per mole of the perfluoroalcoholate obtained in the first reaction step.
Mole, preferably 1 to 3 moles. This reaction is preferably carried out in the presence of a reaction solvent, but the use of the reaction solvent is not necessarily required, and can be omitted if necessary. Further, as the reaction solvent, the use of the aprotic polar organic solvent as described above is preferable, but it is not limited to these solvents, and other solvents, for example, a hydrocarbon solvent can be used. The use ratio of the reaction solvent is preferably 2 to 4 parts by weight per 1 part by weight of the perfluoroalcoholate obtained in the first reaction step.
The reaction temperature is usually 30 to 200 ° C., preferably 50 to 200 ° C.
１５０150 ° C. The reaction pressure is not particularly limited, and it can be used at any pressure from the normal pressure to the pressure system. However, from the viewpoint of increasing the yield of the alkylated product and suppressing by-products, the reaction pressure is from normal pressure to 3 kg / cm ^2. The use of a pressure of G is preferred.

When performing the first reaction step and the second reaction step, the number of reaction vessels may be one or two. 1
When one reaction vessel is used, an alkylating agent may be added to the obtained reaction product after the completion of the first reaction step, and the second reaction step may be performed. In this case, it is preferable that the alkylating agent is gradually added dropwise. On the other hand, when two reaction vessels are used, the reaction solution obtained by removing the alkali metal fluoride from the reaction product obtained in the first reaction step is transferred to the second reaction vessel, and an alkylating agent is added thereto. And the second reaction step may be performed. In some cases, perfluoroalcoholate is isolated from the reaction product obtained in the first reaction step, and the isolated perfluoroalcoholate is placed in a second reaction vessel together with a reaction solvent. Can also be implemented. Since both the first reaction step and the second reaction step are preferably performed at atmospheric pressure or a low pressure of 3 kg / cm ² G or less, it is preferable to use a reaction vessel equipped with a reflux tower.

According to the above-mentioned method, the yield is extremely high as compared with the conventional method in which perfluoroacyl fluoride, a reaction solvent, an alkali metal fluoride and an alkylating agent are simultaneously charged into a reaction vessel to carry out the reaction. The desired fluorinated ether can be produced. Specific examples of the fluorine-containing ether obtained as described above include the following. _{(CF 3) CF-CF 2} -O-CH 3, (CF 3) 2 CF-CF 2
—OC ₂ H ₅ , (CF ₃ ) ₂ CF—CF ₂ —OC ₃ H ₆ ,
_{F 3) 2 CF-C 2} F 4 -O-CH 3, (CF 3) 2 CF-C 2 F 4
—OC ₂ H ₅ , (CF ₃ ) ₂ CF—C ₂ F ₄ —OC ₃ H ₆ ,
_{(CF 3) 2 CF-C} 3 F 6 -O-CH 3, (CF 3) 2 CF-C 3
F ₆ -OC ₂ H ₅ , nC ₂ F ₅ OCH ₃ , nC ₃ F ₇ OC
_{H 3, n-C 3 F} 7 OC 2 H 5, n-C 4 F 9 OCH 3, n-C
_{4 F 9 OEt, n-C} 4 F 9 OPr, n-C 5 F 11 OMe,
_{n-C 5 F 11 OEt,} n-C 5 F 11 OPr, (CF 3) 2 CF
_{-C 4 F 8 -O-CH 3} , (CF 3) 2 CF-C 5 F 10 -O-C
_{H 3, (CF 3) 2} CF-C 6 F 12 -O-CH 3 and the like. The branched-chain fluorinated ethers were confirmed to be non-flammable, less likely to explode, exhibit no acute oral toxicity and mutagenicity, and were extremely safe compounds. Further, the fluorinated ether compound has an SP
The value is 7 (cal / cm ³ ) around ^0.5 , and the SP value of CFC-113 which has been conventionally used as a cleaning agent is 7.2 (c
al / cm ³ ) is close to ^0.5 , and can be substituted for CFC-113. Moreover, its surface tension is smaller than that of CFC-113, which is advantageous for precision cleaning and the like.

In the fluorinated ether obtained by the two-step method, a fluorinated ester as an impurity is usually contained in an amount of 0.5 to 5 mol%, particularly
It is contained at a ratio of 0.5 to 3 mol%. According to the present invention, this fluorine-containing ester impurity is substantially zero percent.
(0.1 mol% or less).

In the present invention, in order to remove the fluorinated ester from a fluorinated ether containing a fluorinated ester as an impurity (hereinafter, also simply referred to as a raw material to be treated),
The raw material to be treated is brought into contact with an alkaline aqueous solution. Examples of the contact method in this case include a method of mixing the two, a method of mixing the two with a line mixer, and a method of mixing the two using ultrasonic waves. Also, this contact processing
A continuous type or a batch type may be used. In the alkaline aqueous solution, the alkaline components include NaOH, KO
In addition to basic compounds such as H, CaO, Ca (OH) ₂ , NaHCO ₃ , ammonia and pyridine, basic ion exchange resins and the like can be mentioned. In particular, NaOH, KOH, Ca
Use of an alkali metal hydroxide such as (OH) ₂ or an alkaline earth metal hydroxide is preferred from the viewpoint of cost. The concentration of the basic compound in the aqueous solution is usually 0.1% by weight or more,
It is preferably at least 5% by weight, and the upper limit is a value corresponding to the saturation solubility. The pH of the alkaline aqueous solution is 8 or more, preferably 10 or more, and the upper limit is not particularly limited.

By the contact treatment, the fluorinated ester as an impurity is decomposed, and the decomposed product moves into an aqueous solution and is removed from the fluorinated ether. The decomposition time depends on the efficiency of the apparatus, but usually decomposes completely within 30 minutes. Although the treatment temperature can be room temperature, it can be heated if desired. Generally, when the treatment is performed at a high temperature, the treatment time is shortened. However, when the treatment is performed at an excessively high temperature, the fluorine-containing ether may be partially decomposed. In the case of the present invention, the range of 0 ° C to 100 ° C is preferable. The pressure depends on the treatment temperature and the boiling point of the fluorinated ether, but is preferably in the vicinity of normal pressure. In this case, a reflux tower can be provided. If desired, it is also possible to increase the contact efficiency between the aqueous phase and the organic phase by adding a phase transfer catalyst, a surfactant, an alcohol, a polyether, a ketone, or the like.

The following are examples of the fluorinated ether used as the raw material to be treated. _{C 2 F 5 OCH 3, C} 2 F 5 OC 2 H 5, n-C 3 F 7 OCH 3,
_{n-C 3 F 7 OC 2} H 5, i-C 3 F 7 OCH 3, i-C 3 F 7
_{OC 2 H 5, n-C} 4 F 9 OCH 3, n-C 4 F 9 OC 2 H 5,
_{n-C 4 F 9 OCH 2} CH 2 CH 3, n-C 4 F 9 OCH (C
_{H 3) 2, i-C} 4 F 9 OCH 3, i-C 4 F 9 OC 2 H 5, i
-C ₄ F ₉ OCH ₂ CH ₂ CH ₃ , i-C ₄ F ₉ OCH (C
_{H 3) 2, tert-C} 4 F 9 OCH 3, tert-C 4 F 9
_{OC 2 H 5, tert-C} 4 F 9 OCH 2 CH 2 CH 3, te
_{rt-C 4 F 9 OCH (} CH 3) 2, n-C 5 F 11 OCH 3,
_{n-C 5 F 11 OC 2} H 5, n-C 5 F 11 OCH 2 CH 2 C
_{H 3, n-C 5 F} 11 OCH (CH 3) 2, i-C 5 F 11 OC
_{H 3, i-C 5 F} 11 OC 2 H 5, i-C 5 F 11 OCH 2 CH 2
_{CH 3, i-C 5 F} 11 OCH (CH 3) 2 and the like. The following are exemplified as the fluorine-containing ester as an impurity. CF ₃ COOMe, CF ₃ COOEt, C ₂ F ₅ COOM
_{e, C 2 F 5 COOEt,} n-C 3 F 7 COOMe, n-C
_{3 F 7 COOEt, n-C} 3 F 7 COOCH 2 CH 2 CH 3,
_{n-C 3 F 7 COOCH (} CH 3) 2, i-C 3 F 7 COOM
_{e, i-C 3 F 7} COOEt, i-C 3 F 7 COOCH 2 C
_{H 2 CH 3, i-C} 3 F 7 COOCH (CH 3) 2, n-C 4
F ₉ COOMe, n-C ₄ F ₉ COOEt, n-C ₄ F ₉ C
OOCH ₂ CH ₂ CH ₃ , nC ₄ F ₉ COOCH (CH ₃ )
_{2, i-C 4 F 9} COOMe, i-C 4 F 9 COOEt, i
_{-C 4 F 9 COOCH 2 CH 2} CH 3, i-C 4 F 9 COOC
H (CH ₃ ) ₂ , CH ₃ COOCH ₃ , CH ₃ COOEt,
_{C 2 H 5 COOMe, C 2} H 5 COOEt like.

When the fluorine-containing ester contained in the reaction product containing the fluorine-containing ether obtained from the reaction step is decomposed and removed, the reaction product can be directly brought into contact with an alkaline aqueous solution. Can be roughly purified to remove components other than the fluorinated ether contained in the reaction product in advance, and then contacted with an alkaline aqueous solution.

[0019]

Next, the present invention will be described in more detail by reference examples and examples. In addition,% shown below is wt%
It is. The reagents used in the following reference examples (production examples of fluorine-containing ethers) are as follows. Spray-dried KF (Kurocat F): Morita Chemical Co., Ltd. C ₃ F ₇ COCl: Aldrich Co., Ltd. C ₃ F ₇ COF: Sale of Daikin chemical products C ₄ F ₉ COCl: Sale of Daikin chemical products (CF ₃ ) ₂ CFCF ₂ COF : Daikin Chemicals Sales Dimethyl Sulfate: Kanto Kagaku Kogyo Co., Ltd., Deer 1st Grade Diethyl Sulfate: Tokyo Kasei Kogyo Co., Ltd. Dinormal Propyl Sulfate: Tokyo Kasei Kogyo Co., Ltd. Ziglyme: Tokyo Kasei Kogyo Co., Ltd. Sodium Hydroxide: Wako Pure Chemical Co., Ltd. Manufactured anhydrous sodium sulfate: manufactured by Wako Pure Chemical Industries

Reference Example 1 500 g of diglyme as a reaction solvent and 174.3 g of KF (3 mol) were placed in a 1500 ml stainless steel autoclave equipped with a dropping funnel for high-pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas inlet and a discharge pipe. ) And sealed. Thereafter, a refrigerant at −20 ° C. is passed through the reflux tower,
While stirring at 0 rpm, the temperature was raised to 50 ° C., and C ₃ F ₇ C
232.5 g (1 mol) of OCI was added dropwise over 30 minutes. Then, after the temperature was gradually raised to 70 ° C., 252.3 g (2 mol) of dimethyl sulfuric acid was added dropwise over 1 hour. After completion of the dropwise addition, the reaction was carried out at 70 ° C. for 1 hour. C ₃ F ₇ C
The pressure increased to a maximum of 1.5 kg / cm ² G at the time of the dropwise addition of OCI, but dropped to 1 kg / cm ² G after the reaction was completed. After completion of the reaction, the product was extracted by a reduced pressure flash, and collected by cooling in an ethanol / dry ice bath (internal temperature: 5).
0-100 ° C). The collected product contained 2% of low boiling compounds such as CH ₃ F and CH ₂ F ₂ . The collected matter was washed with ice water in a separating funnel, and then an aqueous sodium hydroxide solution was gradually added to make the alkali side, and the collected matter was separated. The organic layer (lower layer) was further washed with pure water, dried over anhydrous sodium sulfate, and purified by atmospheric distillation. As a result, the GC yield (C ₄ F ₉ OMe) was 99%, the recovery rate was 93%, and 1% of ester was formed as a by-product (mol% based on fluorine-containing ether; the same applies hereinafter).

Reference Example 2 In a 1500 ml stainless steel autoclave equipped with a dropping funnel for high pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas introduction and discharge pipe, diglyme (500 g), K
F174.3 g (3 mol) was charged and sealed. Thereafter, a refrigerant at -20 ° C is passed through the reflux tower, and C ₃ F ₇ COF 2
16 g (1 mol) were introduced from a gas tube. Thereafter, the temperature was gradually raised to 70 ° C., and 252.3 g of dimethyl sulfuric acid was obtained.
(2 mol) was added dropwise over 1 hour. After dropping, 7
The reaction was performed at 0 ° C. for 1 hour. The recovery and purification of the reaction product were the same as in Reference Example 1. As a result, the GC yield (C ₄ F ₉ OM
e) was 99%, the recovery was 93%, and 1% of ester was formed as a by-product.

Reference Example 3 In a 1500 ml stainless steel autoclave equipped with a dropping funnel for high-pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas inlet and outlet pipe, diglyme (500 g), K
F174.3 g (3 mol) was charged and sealed. Thereafter, a refrigerant at −20 ° C. is passed through the reflux tower, and C ₃ F ₇ COF (1
mol) was introduced from a gas tube. After that, gradually at 70 ° C
After the temperature was raised to 364.5 g of dinormal propyl sulfuric acid
(2 mol) was added dropwise over 1 hour. After the completion of the dropwise addition, the temperature was gradually raised to 100 ° C., and the reaction was performed for 2 hours. The recovery and purification of the reaction product were the same as in Reference Example 1. As a result, GC
The yield (C ₄ F ₉ OPr) was 87%, the recovery was 85%, and 1% of an ester was formed as a by-product.

Reference Example 4 500 g of diglyme and KF2 were placed in a 1500 ml stainless steel autoclave equipped with a dropping funnel for high pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas introduction and discharge pipe.
32.4 g (4 mol) was charged and sealed. afterwards,
The reflux column flowing -20 ° C. refrigerant, while stirring at 400 rpm, temperature was raised to 50 ℃, C ₄ F ₉ COCl 282.
5 g (1 mol) was added dropwise over 30 minutes. Thereafter, the temperature was gradually raised to 70 ° C., and 252.3 g of dimethyl sulfuric acid was obtained.
(2 mol) was added dropwise over 1 hour. 10 after dropping
The temperature was raised to 0 ° C., and the reaction was performed for 1 hour. Collection of reaction products,
Purification was the same as in Reference Example 1. As a result, the GC yield (C
₅ F ₁₁ OMe) 98% is by-product ester formation amount 2%
The recovery rate was 93%.

Reference Example 5 In a 1500 ml stainless steel autoclave equipped with a dropping funnel for high pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas inlet and outlet pipe, 500 g of diglyme, KF2
32.4 g (4 mol) was charged and sealed. afterwards,
A refrigerant at −20 ° C. was passed through the reflux tower, and the temperature was raised to 50 ° C. while stirring at 400 rpm, and C ₄ F ₉ COCl 282.
5 g (1 mol) was added dropwise over 30 minutes. Thereafter, the temperature was gradually raised to 70 ° C., and 252.3 g of diethyl sulfuric acid was obtained.
(2 mol) was added dropwise over 1 hour. 10 after dropping
The temperature was raised to 0 ° C., and the reaction was performed for 1 hour. Collection of reaction products,
Purification was the same as in Reference Example 1. As a result, the GC yield (C
₅ F ₁₁ OEt) is 89%, the amount of by-product ester produced is 3%,
The recovery was 87%.

Reference Example 6 The reaction solvent diglyme 5 was placed in a 1500 ml stainless steel autoclave equipped with a dropping funnel for high-pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas introduction and discharge pipe.
00g, KF174.3g (3mol), ( CF 3) 2 C
266.0 g (1 mol) of FCF ₂ COF was charged and sealed. Thereafter, a refrigerant at −20 ° C. is passed through the reflux tower,
After the temperature was gradually raised to 70 ° C. while stirring at 0 rpm, 252.3 g (2 mol) of dimethyl sulfuric acid was added dropwise over 1 hour. After completion of the dropping, the temperature was gradually raised to 100 ° C., and the reaction was carried out for 1 hour. The recovery and purification of the reaction product were the same as in Reference Example 1. As a result, GC yield (i-C ₅ F ₁₁ O
Me) was 94%, the amount of by-product ester produced was 3%, and the recovery was 92%.

Reference Example 7 A reaction solvent, diglyme 5, was placed in a 1500 ml stainless steel autoclave equipped with a dropping funnel for high pressure reaction, a reflux tower, a pressure gauge, a thermometer, a stirrer, a gas introduction and discharge pipe.
00g, KF174.3g (3mol), ( CF 3) 2 C
266.0 g (1 mol) of FCF ₂ COF was charged and sealed. Thereafter, a refrigerant at −20 ° C. is passed through the reflux tower,
After the temperature was gradually raised to 70 ° C. while stirring at 0 rpm, 308.4 g (2 mol) of diethyl sulfuric acid was added dropwise over 1 hour. After completion of the dropping, the temperature was gradually raised to 100 ° C., and the reaction was carried out for 1 hour. The recovery and purification of the reaction product were the same as in Reference Example 1. As a result, GC yield (i-C ₅ F ₁₁ O
Et) was 88%, the amount of by-product ester produced was 3%, and the recovery was 85%.

Example 1 nC ₄ F ₉ O containing 2.48% of nC ₃ F ₇ COOMe
5 g of Me and 40 g of a 10 wt% KOH aqueous solution were charged into a pressure-resistant glass container, and stirred at 50 ° C. for 2 hours at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no n-C ₃ F ₇ COOMe was detected. Also, no decomposition of nC ₄ F ₉ OMe was observed.

Example 2 nC ₄ F ₉ O containing 2.48% of nC ₃ F ₇ COOMe
5 g of Me and 40 g of a 5 wt% KOH aqueous solution were charged into a pressure-resistant glass container, and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no n-C ₃ F ₇ COOMe was detected. Also, no decomposition of nC ₄ F ₉ OMe was observed.

Example 3 n-C ₄ F ₉ O containing 2.48% of n-C ₃ F ₇ COOMe
5 g of Me and 20 g of a 1 wt% KOH aqueous solution were charged into a pressure-resistant glass container, and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no nC ₃ F ₇ COOMe was detected. Also, no decomposition of nC ₄ F ₉ OMe was observed.

Example 4 nC ₄ F ₉ O containing 2.48% of nC ₃ F ₇ COOMe
5 g of Me and 40 g of a 5 wt% Ca (OH) ₂ aqueous solution were charged into a pressure-resistant glass container, and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no nC ₃ F ₇ COOMe was detected. Also, no decomposition of nC ₄ F ₉ OMe was observed.

Example 5 nC ₅ F _{11 with} 0.20% nC ₄ F ₉ COOMe
5 g of OMe and 40 g of a 5 wt% KOH aqueous solution were charged into a pressure-resistant glass container, and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no nC ₄ F ₉ COOMe was detected. It was also not observed the degradation of n-C5 ₅ F ₁₁ OMe.

Example 6 i-C ₅ F ₁₁ containing 1.98% of i-C ₄ F ₉ COOEt
5 g of OEt and 40 g of a 5 wt% KOH aqueous solution were charged into a pressure-resistant glass container, and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no iC ₄ F ₉ COOEt was detected. In addition, the degradation of i-C5 ₅ F ₁₁ OEt was not observed.

Example 7 1. n-C ₄ F ₉ OMe containing 12.2% C ₂ H ₅ COOMe
5 g and 40 g of a 10 wt% KOH aqueous solution were charged into a pressure-resistant glass container and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of stirring, the organic phase (lower layer) sampling, washed with water, and was analyzed by gas chromatography C ₂ H ₅
COOMe was not detected. Further, n-C ₄ F ₉ OM
No decomposition of e was observed.

Example 8 ₅ g of C ₂ F ₅ OMe containing 1.31% CF ₃ COOMe
And 40 g of a 10 wt% KOH aqueous solution were charged into a pressure-resistant glass container, and stirred at room temperature for 30 minutes at a stirring speed of 100 rpm. After completion of the stirring, the organic phase (lower layer) was sampled, washed with water, and analyzed by ¹⁹ F-NMR and gas chromatography, but no CF ₃ COOMe was detected. Also,
No decomposition of C ₂ F ₅ OOMe was observed.

Example 9 Diglyme solvent (10 g), KF (3.48 g), n-
After stirring C ₃ F ₇ COF (4.3 g) at 70 ° C., 3 g of dimethyl sulfate was added dropwise. After completion of the dropwise addition, stirring was continued at 70 ° C. for 2 hours. After completion of the reaction, a portion of the product ¹⁹ F-N
Analysis by MR revealed that nC ₄ F ₉ OMe had an integrated value of 10
With respect to 0, nC ₃ F ₇ COOMe produced an integrated value of 1.4. 40g of NaOH aqueous solution (10wt%)
After stirring at room temperature for 30 minutes, 120 cc of water was added, and after stirring, the organic phase (lower layer) was sampled and washed with water.
It was analyzed by gas chromatography and ¹⁹ F-NMR,
n-C ₃ F ₇ COOMe was detected. Also, n-
No decomposition of C ₄ F ₉ OMe was observed.

[0036]

According to the present invention, a fluorinated ester as an impurity is selectively and efficiently decomposed and removed from a fluorinated ether containing a fluorinated ester as an impurity, and a high-purity fluorinated ether is obtained in a high yield. Can be obtained at a rate.

────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yuji Mochizuki 6F, Hongo Wakai Building, Hongo 2-40-17, Hongo, Bunkyo-ku, Tokyo New Refrigerant Project Room, etc. (72) Etsuo Fujimoto, Inventor 6-floor Hongo Wakai Building, Hongo 2-40-17, Bunkyo-ku, Tokyo New Research Project Room for New Refrigerants, etc. (72) Inventor Akira Sekiya 1-1-1, Higashi, Tsukuba, Ibaraki Pref. Examiner in the Technical Research Laboratory Toshiro Fujimori (56) References JP-A-8-3075 (JP, A) JP-A-8-291084 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 41/44 C07C 43/12

Claims (3)

(57) [Claims] [Claim 1] The following general formula (1) In the fluorine-containing ether in the fluorine-containing ether represented
On the other hand, the following general formula (2) contained at a ratio of 0.5 to 5 mol% : In the method for separating a fluorine-containing ester represented by the fluorine-containing ether from the fluorine-containing ether, the fluorine-containing ether containing the fluorine-containing ester is brought into contact with an alkaline aqueous solution to decompose the fluorine-containing ester, Purification method. 2. The fluorine-containing ether having 10 or more carbon atoms.
Fluorinated ether containing at least 5 fluorine atoms below
InAnd the following general formula (3) R _f ¹ COX (3) (Where R _f ¹ Has the same meaning as above, and X is halogen
Represents an atom) perfluoroacyl halide
Alkali metal fluoride in aprotic polar organic solvents
Reaction step of reacting with a compound, and the obtained reaction product
Comprising a second reaction step of reacting an alkylating agent with
Is obtained in The method of claim 1. 3. A proportion of the fluorine-containing ester in the fluorine-containing ether after the fluorine-containing ether is contacted with said aqueous alkaline solution is substantially zero% claim 1 or 2
the method of.