JP2003012605A - Method for producing fluorinated vinyl ether - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing fluorinated vinyl ether from a fluorinated acid fluoride compound having an ester group which is a precursor of carboxylic acid in a high yield. SOLUTION: This method for producing fluorinated vinyl ester is provided by first converting the fluorinated acid fluoride compound having a specific structure to its potassium salt, and then performing a heat decomposition reaction without solvent.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to a diaphragm for salt electrolysis and
Which is a useful raw material monomer for fluoropolymers
The present invention relates to a method for producing a fluorinated vinyl ether. [0002] 2. Description of the Related Art Salt electrolysis for producing caustic soda and chlorine
The ion exchange membrane method is widely used for
The current efficiency is excellent for an ion exchange membrane
Perfluorosulfonic acid polymer and perfluorocal
Laminated type film of boronic acid polymer is mainly used
I have. Perfluorosulfonic acid polymer used
And perfluorocarboxylic acid polymer
General formula (4): Embedded image (Wherein, m = 0 to 1, n = 1 to 5; X = COO
H, SO_ThreeH. ) Structure is common
(Haruhisa Miyake, "Development of Fluorine-based Materials", p. 105, CIE
Moussy, 1994). These polymers are generally
Equation (5): Embedded image (Where m and n are the same as those in the above general formula (4), X ′ = CO
OR, SO_TwoF and R are alkyl groups. )
Fluorinated vinyl ether monomer and tetrafluoroethyl
After forming a copolymer with styrene (TFE), the hydrolysis reaction
It is obtained by applying a reaction. [0003] This fluorinated vinyl ether monomer
The raw material of the perfluorocarboxylic acid polymer is
X '= COOR monomer in the above general formula (5)
There are various manufacturing methods proposed for each structure.
Have been. For example, the terminal CH_ThreeOCF_TwoCF_Two-Group
Of vinyl ether with a strong acid to introduce ester groups
Method (JP-A-60-156632),
Esterification of vinyl ether with acid fluoride
Method (Japanese Patent Laid-Open No. 54-112822), ICF_Two
CF_TwoO-structure precursor to vinyl by de-IF reaction
Method for introducing a group (JP-A-55-31004), etc.
However, the synthesis of raw materials is easy and the yield is relatively high.
The production method to give acid fluoride as shown below
It is a method of manufacturing by pyrolysis, and is the most useful manufacturing method.
One. [0004] Embedded image (Where M is a metal such as an alkali metal) In this method, heated alkaline powder such as sodium carbonate
Feeding the acid fluoride of the above general formula (1) into the powder;
Cooling and collecting vinyl ether monomer generated by thermal decomposition
(Hereinafter referred to as a flow method), the above general formula (1)
Is reacted with an alkali once to obtain the above-mentioned general formula
After being converted to the carboxylate of (6), it is heated and pyrolyzed to
A method for obtaining a phenyl ether monomer (hereinafter referred to as a two-stage method)
Is known. An example of the former flow method is disclosed in
JP-A-132519 discloses the above general formulas (1), (6),
In (2), m = 1 or 2, n = 2, M = Na, R
= CH _ThreeIn the case of m = 1, the yield is 67
%, M = 2, vinyl ether monomer with a yield of 61%
-Has been obtained. On the other hand, an example of the latter two-stage method is disclosed in
No. 78827, m = 0, n = 3, M =
Na, R = C_TwoH_Five61%, m = 0, n =
3, M = K, R = C_TwoH_Five63-65% in the case of
m = 1, n = 3, M = K, R = C_TwoH_FiveIn case of 5
A result of 1% has been reported. That is, in any case
But the yield is only in the 50-60% range,
Did not. In particular, in the former flow method, the acid
Since the boiling point of the oxide is lower than the reaction temperature,
There was also a disadvantage that the contact efficiency was poor and it was difficult to increase the conversion. Further, Japanese Patent Application Laid-Open No. 7-505164 discloses
In the general formula (1), m = 1, n = 2, and R = C
H_ThreeAfter conversion of the acid fluoride to the silyl ester,
By reacting with KF at a temperature, the above-mentioned general formula (2)
Methods for obtaining vinyl ethers are disclosed. But
In this method, the process is complicated and the yield is 69%.
Yes, not much. The above
In the general formula (6), when M is sodium and potassium
This suggests the difference in reactivity with
There have been no such reports, and in fact, JP-A-52-78827.
No significant difference was recognized in the gazette examples (m = 0, n = 3).
Had not been. As described above, the above general formula
From the acid fluoride represented by (1), the above-mentioned general formula (2)
The method for producing a fluorinated vinyl ether represented by
Thus, a high-yield production method has not been known. Those public
The reaction results of the intellectual literature are summarized below. <Flow method> (JP-A-53-132519) m = 1, n = 2, M = Na 67% yield m = 2, n = 2, M = Na yield 61% <Two-step method> (JP-A-52-78827) m = 0, n = 3, M = Na yield 61% m = 0, n = 3, M = K Yield 63-65% m = 1, n = 3, M = K Yield 51% Therefore, the acid fluoride of the general formula (1) is more
The method for producing the fluorinated vinyl ether of the formula (2) is
Inefficient, more economically advantageous, high-yield production process
Was desired. [0008] The present invention solves the above problems.
The specific acid fluoride in the above general formula (1)
The specific fluorinated vinyl in general formula (2)
With the aim of providing a method for producing
Target. [0009] Means for Solving the Problems The present inventors have made the above general description
From the acid fluoride represented by the formula (1), the general formula (2)
To produce fluorinated vinyl ether represented by
As a result of intensive studies to develop a method, the above general formula
Treating the specific acid fluoride in (1) under specific conditions
By converting, 100% conversion, high yield and high quality
Specific fluorinated vinyl ether in the above general formula (2)
To achieve the present invention.
Reached. That is, the present invention provides the following general formula (1): Embedded image (Wherein, m is an integer of 0 to 1, n is an integer of 1 to 5, R is alkyl
Group. ), The following general formula
(2): Embedded image (Where m, n, and R are the same as those in the general formula (1)).
To produce fluorinated vinyl ethers
In the general formula (1), m = 1, n = 2 acid fluoride
The following formula (3) derived from: Embedded image (In the formula, R is the same as the general formula (1).)
By thermally decomposing the lithium salt without solvent, the above general formula
In (2), the fluorinated vinyl ether having m = 1 and n = 2
Fluorinated vinyl ether characterized by producing
Is a manufacturing method. Hereinafter, the present invention will be described in detail. Book
In the manufacturing method of the invention, first, the structure applied is the above general formula
In (6), an acid fluoride having m = 1 and n = 2, that is,
Notation (7): Embedded image (Wherein R is the same as in the above general formula (1))
From the formula (2), m = 1 and n = 2
Fluorinated vinyl ether, that is, the following formula (8): Embedded image (Wherein R is the same as in the above general formula (1))
Limited to the method for producing a nyl ether, and the reaction
By specifying the conditions, it is possible to achieve a conversion of 100%.
Occasionally, the reaction yield is specifically increased. Specific reactions
The condition is that the two-step method is used instead of the flow method.
The intermediate carboxylate is limited to potassium salt
That is, the thermal decomposition is performed without a solvent. Important points in the manufacturing method of the present invention
Is an acid fluoride of the above formula (7) having a specific structure.
Is that it is converted to the potassium salt of the above formula (3). Obedience
The acid fluorinated compound of the above formula (7) has been widely used in the conventional method.
When converting rulide to the sodium salt, the above formula (3)
The corresponding sodium salt is dissolved at room temperature or at the temperature before pyrolysis.
It is easy to melt, and in this case, the above formula (7)
An ester of the following formula (9) in which the acid fluoride is esterified
Stele compound: Embedded image (Wherein R is the same as in the general formula (1)).
Thus, it was found that the yield of the target product was reduced. I
However, we did not call this a sodium salt,
To be a potassium salt of the above formula (3) having a specific structure
Keeps carboxylate in solid state even at thermal decomposition temperature
I found that. Therefore, once completely converted to carboxylate
Even if it is exchanged, the heat component remains in a solid state (a state without fluidity).
And the fluidization of the carboxylate
Since there is no side reaction, the target compound of the above formula (8) can be obtained in high yield.
The present invention has found that
Completed. The acid fluoride of the above formula (7) is
As a method for converting to the potassium salt of (3), a method in a solvent may be used.
Or react with alkali containing potassium atom without solvent
Just fine. Specific examples of the alkali containing a potassium atom include:
Include potassium carbonate, potassium hydroxide, potassium phosphate,
Potassium acetate and the like can be mentioned.
Potassium carbonate is preferred because it can be removed as a gas. Charcoal
As potassium acid, granules, powders, fine
Powder, granular with increased specific surface area, or
Powder or fine powder
it can. In addition, it is preferable to dry well before use.
No. When a solvent is used in the reaction with an alkali,
A neutral solvent is used. Specifically, water or methanol
Alcohol, such as ethanol, propanol,
Lahydrofuran, dioxane, ethylene glycol dime
Tyl ether, diethylene glycol dimethyl ether
Such as ethers, acetonitrile, propionitrile, etc.
Nitriles, dimethylformamide, dimethylacetate
Amides such as amides, dimethyl sulfoxide and the like.
It is. These solvents need to be removed after the reaction,
A solvent having a boiling point of 100 ° C. or less, which is easy to remove, is preferred. Also
If a protic solvent remains during thermal decomposition,
Protonated CF instead of Nyl group_ThreeCHF-
Aprotic solvent as a solvent
Medium is preferred. Solvents that meet these conditions include
Trahydrofuran, ethylene glycol dimethyl ether
And acetonitrile. Reaction with alkali
If a solvent is used at the reaction temperature,
Is preferably in the range of 0 to 80 ° C, more preferably in the range of 20 to 60 ° C.
More preferred. The reaction with alkali is performed without solvent.
You can also. In this case, the counter ion component of potassium
Performs reaction with potassium carbonate without solvent, which does not remain after reaction
Is preferred. In this case, the reaction temperature is 50 to 15
0 ° C is preferred, and 80 to 120 ° C is more preferred. [0013] The catalyst used when converting to a potassium salt
The amount of lukali is generally that acid fluoride is completely potassium
It is sufficient to use the equivalent required to convert to salt, but it is necessary
May be used in excess. For example, for potassium carbonate
In general, the range is generally equivalent to 4 equivalents, preferably equivalent to 2 equivalents.
Used in the range of equivalents. In the production method of the present invention,
The acid fluoride of the above formula (7) used has a high purity.
preferable. The acid fluoride of the above formula (7) contains impurities.
If this occurs, side reactions tend to occur and the yield decreases. this
In order to substantially eliminate the effects of such impurities,
The purity of the acid fluoride of the formula (7) is preferably 80% by weight or more.
More preferably, it is 90% by weight or more.
It is preferably at least 95% by weight. [0014] In addition, the acid fur
When producing an oride, the following general formula (10): Embedded image (Wherein, m is 0 or an integer of 2 or more, and R is the above general formula.
Same as (1). ) Is generally a by-product of acid fluoride
And therefore they are introduced as impurities
It is possible. That is, the acid fluoride of the above formula (7)
When the compound of the general formula (10) is contained as an impurity,
Preferably the amount is less than 20% by weight,
Preferably less than 10% by weight, more preferably 5% by weight.
% By weight. In the manufacturing method of the present invention, the above formula (7)
The alkyl group of R in the acid fluoride of
It is preferable that the number of carbon atoms is small because it is easy.
A lower alkyl group having 1 to 4 prime numbers is employed. Specific of R
Examples include methyl, ethyl, propyl, isop
Examples thereof include a propyl group and an n-butyl group.
Groups and ethyl groups are preferred, and methyl groups are particularly preferred. Up
The potassium salt of the above formula (3) should be heated above the thermal decomposition temperature.
Decarboxylation reaction to produce vinyl ether of the above formula (8)
To achieve. This thermal decomposition itself can be carried out with or without a solvent.
Although it proceeds, it is not necessary to suppress side reactions and increase the yield.
Must be done with solvent. Heating temperature causes the decarboxylation reaction to proceed
Temperature is acceptable, but generally 120 to 30
It is carried out at 0 ° C, preferably at 150 to 250 ° C. Thermal decomposition
In order to prevent the generated vinyl ether from staying in the system
And the thermal decomposition temperature is
If the boiling point is higher than the pressure, the vinyl ether
It is preferable to guide the crab to a crab and collect it. Ma
Even if the thermal decomposition temperature is below the boiling point of vinyl ether
Such as reducing the pressure inside or flowing an inert gas
It is preferable to remove vinyl ether from the system by a method.
Good. Fluorinated vinyl prepared by the method of the present invention
Ethers are obtained in high yields and have 100% conversion.
Contains no unreacted acid fluoride and has few side reactions
In high purity. Therefore, the production method of the present invention
It has the feature that subsequent purification is very easy. that's all
As described above, the production method of the present invention is an ion exchange membrane for salt electrolysis.
Fluorinated vinyl ether used as a raw material for
It can be produced in high yield and is very useful. Also, the person of the present invention
The vinyl ether produced by the method has high purity,
It has the feature that purification as a process is easy. Hereinafter, the present invention will be described with reference to examples.
You. In addition, the reaction yield was determined by converting from the purity of the raw material. EXAMPLE 1 14.5 g of charcoal was placed in a 100 ml flask.
Potassium salt and 20 ml of ethylene glycol dimethyl ether
And add it to the acid fluoride of the above formula (7).
And R = CH_Three48.8 g of the compound (purity 96% by weight)
Was added dropwise at 40 ° C. The stirring was continued for 2 hours.
After that, the solvent is distilled off under reduced pressure, and further dried at 100 ° C. under vacuum.
Thus, a solid potassium salt containing KF was obtained. Completely potash
Is converted to um salt¹⁹Confirm by F-NMR
Was. Attach the distillation head and condenser to the flask,
Heat to 200 ° C under normal pressure until liquid formation stops
Heating was continued at 200 ° C. Meanwhile, the potassium salt is solid
Had maintained his state. 38.3 g of the recovered liquid is gasket
Analysis by chromatography showed that the equation (8)
Nyl ether was contained at a purity of 96% by weight (yield 9
1%). The diester of the above formula (9) contains 2% by weight.
Had been rare. [0018] Comparative Example 1 11.1 g of carbonic acid instead of potassium carbonate
The reaction was carried out in the same manner as in Example 1 except that sodium was used.
Was. The sodium salt obtained by distilling off the solvent is a viscous liquid
Met. In addition, 35.3 g of the liquid obtained by pyrolysis was
When analyzed by chromatography, the above formula (8) was obtained.
Of vinyl ether was 80% by weight (yield 66
%), And 17% by weight of the diester of the above formula (9) is contained.
Was. Comparative Example 2 18.5 g of a 200 ml three-necked flask
Potassium carbonate was charged and heated to 220 ° C. this
Among them, the same acid fluorinated compound of the above formula (7) used in Example 1 was used.
48.8 g of rulide were added dropwise little by little. The product is
It was collected with a denser, and 39.2 g of the obtained liquid was
Analysis by chromatography showed that the equation (8)
Nyl ether is 65% by weight (yield 61%, selectivity 76
%), 25% by weight of unreacted acid fluoride,
The diester of (9) was contained in an amount of 1% by weight. [0019] Comparative Example 3 14.2 g of carbonic acid instead of potassium carbonate
The reaction was carried out in the same manner as in Comparative Example 2 except that sodium was used.
Was. 40.3 g of the obtained liquid is subjected to gas chromatography.
When the vinyl ether of the above formula (8)
8% by weight (yield 64%, selectivity 72%), unreacted acid
13% by weight of rulide and 9% of diester of the above formula (9)
% By weight. [0020] Example 2 In a 200 ml three-necked flask, 27.6 g of
Put potassium carbonate, and at 100 ° C, same as in Example 1.
48. Acid fluoride of the above formula (7) (purity: 95% by weight)
8 g was added dropwise. After continuing the reaction for another 2 hours,
The body solidified. At this stage, ¹⁹Acid Fluoride by F-NMR
Make sure that the salt is completely converted to potassium salt
Was. Heat the flask to 200 ° C as it is
Responded. The obtained 39.5 g of liquid was subjected to gas chromatography.
Analysis of the vinyl ether of the above formula (8)
91% by weight (89% yield).
It contained 4% by weight of ester. [0021] Comparative Example 4 In place of the acid fluoride of the above formula (7), C
H_ThreeOCOCF_TwoCF_TwoOCF (CF_Three) COF (above
In the general formula (1), m = 0, n = 2, R = CH_Three)
Example 1 (purity 93% by weight) except that 32.2 g was used.
The reaction was carried out in the same manner as described above. Completely converted to potassium salt in the middle
What is being done¹⁹Confirmed by F-NMR. Potassium salt
Decomposes when heated to 200 ° C, producing violent white smoke
However, heating was continued at 200 ° C until the generation of liquid stopped.
Was. Gas chromatography of 15.7 g of the recovered liquid
As a result of the above analysis, in the above general formula (2), m =
0, n = 2, R = CH _ThreeContaining a small amount of vinyl ether
It was a rough mixture. Comparative Example 5 11.1 g of carbonic acid instead of potassium carbonate
The reaction was carried out in the same manner as in Comparative Example 4 except that sodium was used.
Was. The sodium salt formed in the middle is a viscous liquid.
Was. In addition, 16.5 g of the liquid obtained by the thermal decomposition was subjected to gas chromatography.
When analyzed by chromatography, the same vinyl
It was a complex mixture containing a small amount of thiol ether. [0022] Comparative Example 6 In place of the acid fluoride of the above formula (7)
In the general formula (1), m = 1, n = 3, R = CH_Threeof
53.8 g of acid fluoride (purity 95% by weight), potassium carbonate
Instead of using 11.1 g of sodium carbonate instead of
The reaction was carried out in the same manner as in Example 1. Solvent
The sodium salt obtained was a viscous liquid. Also the heat
39.2 g of the liquid obtained by the solution was subjected to gas chromatography.
As a result, m = 1 in the general formula (2),
n = 3, R = CH_Three73% pure vinyl ether
% (Yield 64%), and the diester compound was 18% by weight.
% Was included. [0023] As described above, the production method of the present invention provides
Fluorinated vinyl acetate used as a raw material for exchange membranes
Ter can be produced in high yield and is very useful. Again
Vinyl ether produced by the Ming method has high purity.
And it is easy to purify as a post-process.
You.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Nobuyuki Uematsu             1 Asahi Kasei stock, 2 Samejima, Fuji City, Shizuoka Prefecture             In the company F-term (reference) 4H006 AA02 AC26 BB15 BC10 BE12                       BM10 BM71 BP10 KF10

Claims (1)

[Claim 1] The following general formula (1): (Wherein, m is an integer of 0 to 1 and n is an integer of 1 to 5 and R is an alkyl group) from the acid fluoride represented by the following general formula (2): (Where m, n, and R are the same as those in the general formula (1)). In the production of the fluorinated vinyl ether represented by the general formula (1), an acid fluoride having m = 1 and n = 2 in the general formula (1) is used. Induced, the following formula (3): (Wherein R is the same as in the above general formula (1)) by thermally decomposing the potassium salt represented by the general formula (1) without solvent to obtain a fluorinated vinyl ether having m = 1 and n = 2 in the above general formula (2). A method for producing a fluorinated vinyl ether, characterized by producing