JP2002037880A - Method of producing fluorine containing polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of producing bifunctional perfluoro polyether with high molecular weight at high selectivity by utilizing a solution containing a special initiator as a polymerization catalyst. SOLUTION: The method of producing perfluoro polyether comprises polymerizing hexafluoropropylene oxide in a solution containing a polymerization initiator (A) expressed by the formula [I] below and an aprotic polar solvent: (FOC)x- Rf-(CF2OCs)y (wherein Rf represents perfluoroalkylene having 1 to 4 carbon atoms or perfluoroalkylene including an ether bond having 2 to 10 carbon atoms; and x and y have relations x+y=2 and 0.1<y<2).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a fluoropolymer. More specifically, the present invention relates to a method for producing perfluoropolyether by polymerizing hexafluoropropylene oxide in a special polymerization initiator-containing solution.

[0002]

BACKGROUND OF THE INVENTION Bifunctional perfluoropolyether oligomers are capable of performing a crosslinking reaction, increasing the molecular weight, etc., by utilizing functional groups at both ends, and have excellent solvent resistance and chemical resistance. It is useful as a resin for sealants, adhesives, vulcanized rubber molded products, and the like. For example, molded products such as O-rings, gaskets, diaphragms, tubes,
Alternatively, the bifunctional perfluoropolyether can be preferably used as a resin used for a sealing agent for piping in a chemical plant, a sealing agent for a tank flange, an adhesive, and the like.

[0003] Conventionally, as a method for producing a bifunctional perfluoropolyether (hereinafter sometimes referred to as "PFE"), hexafluoropropylene oxide (hereinafter referred to as "H
FPO ". ) Is polymerized in the presence of a suitable catalyst or polymerization initiator. Such HFPO polymerization is a polymerization method in which chain transfer from a compound other than a polymerization initiator, for example, a chemical species such as H ₂ O, HF or a carbonyl group is extremely likely to occur. By minimizing the contamination of chemical species, the polymerization reaction from such chemical species can be suppressed, and the polymerization reaction can be performed under conditions that can suppress the formation of by-products other than the target bifunctional perfluoropolyether. It was important to do it. In particular, since H ₂ O is present everywhere, such as in the air, and is highly likely to be mixed into the polymerization reaction system, elimination of such mixing was an important problem.

It has been known that in order to improve the selectivity of the bifunctional perfluoropolyether, it is necessary to carry out the reaction while keeping the polymerization temperature of HFPO as low as possible. In the polymerization of HFPO,
It has been known that lowering the polymerization temperature, in addition to suppressing chain transfer, increases the selectivity of the reaction and increases the degree of polymerization of the resulting polymer. Furthermore, when a bifunctional initiator is used as a polymerization initiator, a monofunctional polymer (by-product)
It was also known that the production of was reduced.

[0005] J. J. MACROMOL. SCI. −
CHEM. , 48 (3), 499-520 (1974), the presence of hexafluoropropene (hereinafter sometimes referred to as "HFP") during HFPO polymerization prevents chain transfer and the degree of polymerization of the resulting polymer. Are described. US Patent No. 3,660,3
No. 15 and Japanese Patent Publication No. 53-5360, cesium fluoride and tetraglyme and FOCCF (CF ₃ )
The following formula [V] in a homogeneous solvent obtained by mixing OCF ₂ CF ₂ OCF (CF ₃ ) COF and separating excess cesium fluoride

[0006]

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[0007] A method for producing bifunctional perfluoropolyether by reacting HFPO at a low temperature is described. The present inventors disclose the aforementioned US Pat. No. 3,660,31.
No. 5 and Japanese Patent Publication No. 53-5360, a compound represented by the general formula [V] is synthesized, and a bifunctional perfluoropolyether is produced from HFPO in the presence of the compound. However, as shown in Comparative Examples 1 and 2 of the present specification, when the maturity or concentration of the catalyst deviates from certain conditions, the degree of polymerization and selectivity of the bifunctional perfluoropolyether are low, There was a problem of lack of practicality.

Japanese Patent Application Laid-Open No. 10-101788 discloses that in producing a bifunctional perfluoropolyether, heat of polymerization is removed from a high-viscosity HFPO polymerization system to lower the polymerization temperature and increase the selectivity of the reaction. In addition, a method is described in which a liquefied gas of fluorocarbons having 1 to 4 carbon atoms is added to a reaction system to suppress chain transfer, and HFPO is polymerized while evaporating the liquefied gas from the polymerization system. However, in this method, in order to suppress a side reaction such as generation of a monofunctional product, it is necessary to prevent the presence of excessive HFPO, and there is a problem that control of the reaction may be difficult.

Accordingly, it is difficult to completely remove chain-transferable H ₂ O, HF or carbonyl group-containing compounds from HFPO which is a raw material of perfluoropolyether. Even so, it has been desired to develop a method for producing a bifunctional perfluoropolyether that can be easily and easily obtained with a high degree of polymerization and high selectivity.

[0010] Therefore, the present inventors have studied intensively to solve the above problems, comprises a polymerization initiator having a specific structure, free in solution Cs ⁺ F ^- polymerization initiator-containing solution which does not contain the When using as a polymerization catalyst, it was found that a bifunctional perfluoropolyether could be obtained with a high degree of polymerization and high selectivity, and the polymerization initiator-containing solution was found to be liquid even at a low temperature. The invention has been completed.

[0011]

An object of the present invention is to provide a polymer having a high degree of polymerization and high selectivity.
It is an object of the present invention to provide a simple method for producing a bifunctional perfluoropolyether.

[0012]

SUMMARY OF THE INVENTION A method for producing a perfluoropolyether according to the present invention is represented by the following general formula [I]:

[0013]

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[In the formula [I], Rf represents 1 to 4 carbon atoms.
Perfluoroalkylene, or 2 to 10 carbon atoms
Wherein x and y satisfy the relationship of x + y = 2 and 0.1 <y <2. And a perfluoropolyether is obtained by polymerizing hexafluoropropylene oxide in the presence of a polymerization initiator-containing solution comprising a polymerization initiator (A) represented by the following formula: and an aprotic polar solvent. .
Rf in the general formula [I] is the following general formula [II]

[0015]

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[In the formula [II], Rf ′ has 2 to 2 carbon atoms.
It is preferably 6 perfluoroalkylene. The polymerization of the hexafluoropropylene oxide is -3.
It is preferable to carry out at 0 ° C. or lower. The polymerization initiator (A)
Is preferably 4 × 10 ⁻⁴ mol / g or more in the polymerization initiator-containing solution.

In the polymerization of hexafluoropropylene oxide, hexafluoropropylene is further converted to
20 to the hexafluoropropylene oxide
It can be used in an amount of up to 50% by weight. The polymerization initiator (A) has the following general formula [III]

[0018]

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In [III], Rf ″ represents a perfluoroalkylene group having 1 to 4 carbon atoms or a perfluoroalkylene group having 2 to 10 carbon atoms and having an ether bond. ] Is preferably obtained by reacting perfluorodicarboxylic acid fluoride (B) represented by the formula (I) with CsF in an aprotic polar solvent. The perfluorodicarboxylic acid fluoride (B) has the following general formula [IV]

[0020]

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[In the formula [IV], Rf ′ ″ represents 2 carbon atoms.
And represents 4 to 4 perfluoroalkylene groups. ] Is preferable. Usage ratio of the perfluorodicarboxylic acid fluoride (B) and the CsF (CsF / perfluorodicarboxylic acid fluoride (B) (molar ratio))
Is preferably 0.1 or more and less than 2.

The aprotic polar solvent is preferably diglyme, triglyme, tetraglyme or sulfolane.

[0023]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, the present invention will be described in more detail. The method for producing a perfluoropolyether according to the present invention is characterized in that hexafluoropropylene oxide is polymerized in the presence of a special polymerization initiator-containing solution to obtain a perfluoropolyether. First, the polymerization initiator-containing solution will be described. <Polymerization initiator-containing solution> The polymerization initiator-containing solution according to the present invention has the following general formula [III]

[0024]

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[In the formula [III], Rf ″ has 1 to 1 carbon atoms.
4 perfluoroalkylene groups or 2 to 1 carbon atoms
A perfluoroalkylene group having an ether bond of 0 is shown. The perfluorodicarboxylic acid fluoride (B) and CsF are mixed and reacted in a molar ratio of 1: 0.1 to less than 2.0 in an aprotic polar solvent to obtain a compound represented by the following general formula: Formula [I]

[0026]

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[In the formula [I], Rf represents 1 to 4 carbon atoms.
Perfluoroalkylene, or 2 to 10 carbon atoms
Wherein x and y satisfy the relationship of x + y = 2 and 0.1 <y <2. ] The solution catalyst which produced | generated the polymerization initiator (A) represented by this. In the present specification, the polymerization initiator represented by the above formula [I] includes the following general formulas [I-1] and [I-2]

[0028]

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[In the formulas [I-1] and [I-2], Rf is a perfluoroalkylene having 1 to 4 carbon atoms or a perfluoroalkylene having an ether bond having 2 to 10 carbon atoms] Wherein x and y in the formula [I] are polymerization initiators represented by the above general formulas [I-1] and [I-2]. Two functional groups (-CF ₂ OCs) in the total polymerization initiator according to the mixing ratio of the agent.
And -COF).

Hereinafter, the perfluorodicarboxylic acid fluoride (B), the aprotic polar solvent, the polymerization initiator (A) and the like will be described in detail. (Perfluorodicarboxylic acid fluoride (B)) The perfluorodicarboxylic acid fluoride (B) according to the present invention is represented by the general formula [III].
f ″ represents a perfluoroalkylene group having 1 to 4 carbon atoms or a perfluoroalkylene group having 2 to 10 carbon atoms and having an ether bond.

As such Rf ″, specifically,

[0032]

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And the group represented by In the above formula, n is an integer of 1 to 6. Among them, in the present invention,

[0034]

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The group represented by the formula is preferred. In the present invention, among the perfluorodicarboxylic acid fluorides having such a group, the following general formula [IV] wherein n is an integer of 2 to 4

[0036]

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[In the formula [IV], Rf ′ ″ represents 2 carbon atoms.
And represents 4 to 4 perfluoroalkylene groups. ] Is particularly preferably used. (Aprotic polar solvent) The aprotic polar solvent used in the present invention preferably has a large dielectric constant ε and does not have a proton donating group. For example, in general, when used as a solvent for an organic ion reaction, since it has a high associative ability and a large proton-transforming ability, it dissociates to form a more stable solvation state when used as a solvent for an organic ion reaction. Those that show interaction are preferred.

Examples of such aprotic polar solvents include N, N-dimethylformamide, N, N-dimethylacetamide, tetramethylurea, dimethylsulfoxide, hexamethylphosphoramide, acetonitrile,
Examples include tetramethylene sulfone (sulfolane), propylene carbonate, nitrobenzene, nitromethane, dimethyl cyanamide, tetrahydrofuran, dioxane, pyridine and the like.

Hydrocarbon compounds having at least one, preferably 1 to 3 ether bonds in the molecule can also be preferably used. For example, ethyl methyl ether, diethyl ether, monoglyme (ethylene glycol dimethyl ether), diglyme ( Diethylene glycol dimethyl ether), tetrahydrofuran and the like can also be used.

Further, as chain or cyclic hydrocarbon compounds having five or more ether bonds in the molecule, tetraglyme (tetraethylene glycol dimethyl ether), crown ether (15-crown-5,18)
-Crown-6) can also be used. Among these, in the present invention, it is preferable to use monoglyme, diglyme, tetraglyme or sulfolane,
More preferably, it is desirable to use tetraglyme. (Polymerization Initiator (A) and Polymerization Initiator-Containing Solution) In the present invention, the perfluorodicarboxylic acid fluoride (B) represented by the general formula [III] and cesium fluoride (Cs) are mixed with When mixed and stirred in a protic polar solvent, the following general formula [I]

[0041]

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[In the formula [I], Rf represents 1 to 4 carbon atoms.
Perfluoroalkylene, or 2 to 10 carbon atoms
Wherein x and y satisfy the relationship of x + y = 2 and 0.1 <y <2. ] The polymerization initiator containing solution containing the polymerization initiator (A) represented by this can be obtained. In the method for producing a perfluoropolyether according to the present invention described below, hexafluoropropylene oxide can be polymerized in the presence of the polymerization initiator-containing solution to obtain a perfluoropolyether. In the preparation of the agent-containing solution, the polymerization initiator (A) used in the present invention can be produced by reacting the perfluorodicarboxylic acid fluoride (B) with the CsF at a specific ratio. By using an initiator-containing solution, a bifunctional perfluoropolyether having excellent selectivity and polymerization degree can be obtained.

The mixing ratio (CsF / perfluorodicarboxylic acid fluoride (B) (molar ratio)) is preferably 0.1 or more and less than 2, more preferably 0.3 to 1.8. And particularly preferably 0.5 to 1.
8 is desirable. One of the major factors why the chain transfer is by-produced monofunctional perfluoropolyether occurred, free Cs ⁺ F in the system ^- including but the action of the high by suppressing the amount A bifunctional perfluoropolyether can be obtained with selectivity. Therefore, CsF needs to be less than 2 for FOCRf-COF. As a result, the generation of surplus CsF can be avoided.

The smaller the mixing ratio of CsF, the more
Although the fluidity of the catalyst at a low temperature is maintained and the degree of polymerization and the selectivity can be improved, on the contrary, if the compounding ratio of CsF is too small, water, HF and the like mixed from the raw materials and the like in operation become inoperable. It is difficult to eliminate the effects, resulting in a decrease in selectivity and polymerization degree. Specifically, when the blending ratio is 2 or more, the selectivity of the obtained bifunctional perfluoropolyether is deteriorated, and the generation ratio of the monofunctional perfluoropolyether may increase.

If the blending ratio is less than 0.1, the polymerization rate and selectivity of the bifunctional perfluoropolyether may be reduced during handling or by a chain transfer agent such as H ₂ O or HF mixed from the raw materials. is there. The method for preparing the polymerization initiator-containing solution containing the polymerization initiator (A) is not particularly limited. For example, the perfluorodicarboxylic acid fluoride (B) is placed in a flask equipped with a stirrer into which Cs is inserted. And a mixed solution of the above and an aprotic polar solvent may be added dropwise while stirring the flask. The temperature of the mixing and stirring is not particularly limited, and may be generally performed at about room temperature.

In the polymerization initiator (A), -CF ₂ OC
The formation of the s bond can be confirmed by observing the -COF group at the molecular terminal of the perfluorodicarboxylic acid fluoride (B) in the solution. Specifically, for such a -COF at the molecular end, the integrated value of the F atom of the -COF is measured by ¹⁹ F-NMR from -COF contained in a sample obtained by partially collecting a reaction solution during mixing and stirring. You can confirm it.

More specifically, when perfluorodicarboxylic acid fluoride (B) and cesium fluoride (Cs) are mixed and stirred, after a certain period of time, the terminal-of the raw material perfluorodicarboxylic acid fluoride (B) has a negative polarity. The COF group decreases and the F peak of cesium fluoride disappears in ¹⁹ F-NMR, and the reaction between perfluorodicarboxylic acid fluoride (B) and cesium fluoride (Cs) proceeds almost quantitatively. .

The polymerization initiator thus produced
The concentration of (A) contained in the polymerization initiator-containing solution is 4
× 10^-FourMol / g or more, more preferably
Preferably 4 × 10^-Four~ 20 × 10^-FourMol / g, especially preferred
Or 4 × 10^-Four-10 × 10 ^-FourMol / g
desirable. The concentration is 4 × 10^-FourLess than mol / g
And perfluorodicarboxylic acid fluoride (B)
When polymerized at a low temperature to prevent chain transfer,
Coagulation is more likely to occur. Therefore, the heavy
To reduce the association between the initiators (A),
Fluorodicarboxylic acid fluoride (B)
Reacting with Cium (Cs) at a dilute concentration is heavy.
Co-initiator containing solution can no longer function as a catalyst
Therefore, it is not appropriate. <Production method of perfluoropolyether> According to the present invention
The method for producing perfluoropolyether is as described above.
In the presence of a polymerization initiator-containing solution that can be obtained as
Hexafluoropropylene oxide (HFPO)
Can be obtained together. Specifically, as described above,
The polymerization initiator containing which can be obtained after a fixed period of time
Hexafluoropropylene oxide (HFP)
O) is preferably supplied to carry out the polymerization of HFPO,
As shown in the following formula, the polymerization represented by the general formula [I]
Depending on the type of the initiator (A), it is represented by the following general formula [VI]
Various HFPO polymers (C) can be obtained.

[0049]

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In the above formula [VI], Rf represents 1 to 4 carbon atoms.
Or a perfluoroalkylene group of 2 to 10 carbon atoms
A perfluoroalkylene group having an ether bond, wherein a = b + c. The supply amount of the HFPO is appropriately selected, and is preferably from 10 to 400 mol based on 1 mol of the polymerization initiator (A) in the polymerization initiator-containing solution.
More preferably, it is desirable to carry out in the range of 20 to 200 mol. The supply of HFPO may be in a gaseous or liquid state.

The temperature at the time of mixing the polymerization initiator-containing solution and HFPO is -30 to -40 ° C, preferably -33 to -40 ° C.
The temperature is desirably 38 ° C., and preferably in this range, under such a condition that the temperature is kept constant during mixing.
The supply time is not particularly limited, and the supply is preferably performed for 3 to 120 hours. The reaction temperature after mixing the polymerization initiator-containing solution and HFPO is preferably −30 ° C. or lower, more preferably −50 to −30 ° C., and particularly preferably −35 to −35 ° C.
Desirably, it is −40 ° C.

After completion of the polymerization, the internal temperature is maintained at -40 to -30 ° C., preferably at −35 to -40 ° C., and after aging for about 1 to 10 hours, the temperature is raised. A perfluoropolyether as represented can be obtained. When HFPO is polymerized in the presence of the polymerization initiator (A), hexafluoropropylene is converted to HFP.
O may be supplied simultaneously with the supply of O. The supply amount of such hexafluoropropylene is preferably 20 to 100% by weight, more preferably 30 to 90% by weight, based on the hexafluoropropylene oxide.

[0053]

According to the method for producing perfluoropolyether according to the present invention, a special polymerization initiator-containing solution is used as a polymerization catalyst, so that the bifunctional perfluoropolyether has a high degree of polymerization and high selectivity. And the resulting polymerization initiator-containing solution is highly active, so that even if it contains some chain transfer substance, a high degree of polymerization and a highly selective bifunctional perfluoropolyether can be obtained. Can be.

[0054]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these Examples.

[0055]

[Catalyst Preparation Example 1] [Preparation of catalyst solution (a)] The mixture was calcined at 300 ° C for 2 hours in a 500 ml flask having a sufficiently dried dropping funnel, condenser, gas inlet tube and stirrer, and further pulverized. CsF (4.8 g, 31.6 mm
ol) was inserted. 220 ° C, 1m in this flask
It dried under reduced pressure at mHg for 1 hour. Next, at room temperature (20 ° C)
Bottom, tetraglyme (45 g) and F-CO-C (CF ₃ ) F-OC
F ₂ CF ₂ O-CF (CF ₃ ) -COF (13.5 g, 31.6 mmol) was inserted from the dropping funnel, and after the completion of dropping, the mixture was stirred at a temperature of 30 ° C. Raw material in reaction solution FOC-CF (CF ₃ ) -OCF ₂ CF
_{2 O-CF (CF 3)} 19 of the presence of -COF group at the end of -COF F-N
The stirring was continued while confirming by MR, and the stirring was stopped when the terminal -COF group was reduced to almost half. Room temperature (20
C)), and left undisturbed overnight (about 12 hours).
sF was removed. The resulting catalyst solution polymerization initiator _{CsO-CF 2- CF (CF 3} ) in _{(a) -OCF 2 CF 2 O} -CF (CF 3) Concentration of -CFO is 5
It was calculated to be × 10 ^-4 mol / g. The molar ratio of FOCRfCOF to CsF (FOCRfCOF: CsF) was calculated to be 1: 1.

[0056]

[Catalyst preparation example 2] [Preparation of catalyst solution (b)] In the catalyst preparation example 1, F-CO-CCF ₃ F-OCF ₂ CF ₂ O-CFCF ₃ -CO-F
4.9 g (34.98 mmol) and 7.1 g of CsF (4
The raw materials were mixed and stirred in the same manner as in Catalyst Preparation Example 1 except that 6.71 mmol) was used. In the same manner as in Catalyst Preparation Example 1,
Stirring was stopped when the terminal -COF group was reduced. After leaving it at room temperature (20 ° C.) overnight (about 12 hours), unreacted CsF was removed to prepare a catalyst solution (b). Polymerization initiator (OCF) _0.5 CF (CF ₃ ) -OCF ₂ CF ₂ O-CF (CF ₃ )-(CF
The concentration of ( _2- OCs) _1.5 was calculated to be 5 × 10 ^-4 mol / g. The molar ratio of FOCRfCOF to CsF (FOCRfCOF: CsF) is 1:
1.5 was calculated.

[0057]

[Catalyst preparation example 3] [Preparation of catalyst solution (c)] In catalyst preparation example 1, 6.8 g (43.3 mmol) of CsF and FOCC
10.5 g of F (CF ₃ ) OCF ₂ CF ₂ OCF (CF ₃ ) COF (26.64 mm
ol) and 31.3 g of tetraglyme, except that catalyst preparation example 1 was carried out to prepare a catalyst solution (c). (F
OC) _0.25 CF (CF ₃ ) OCF ₂ CF ₂ OCF (CF ₃ )-(CF ₂ OCs) The concentration of _1.75 is 5 × 10 ⁻⁴ mol / g, and the molar ratio between FOCRfCOF and CsF (FOCRfCOF: CsF) Was calculated as 1: 1.75.

[0058]

[Catalyst preparation example 4] [Preparation of catalyst solution (d)] Except that 2.9 g (19.0 mmol) of CsF was used in catalyst preparation example 1, the same procedure as in catalyst preparation example 1 was carried out. )
Was prepared. (FOC) _1.4 -CF (CF ₃ ) OCF ₂ CF ₂ OCF (CF ₃ )-(CF ₂ -O
Cs) The concentration of _0.6 is 5 × 10 ^-4 mol / g and the FOCRfCOF
And the molar ratio of CsF to 1: 0.6 was calculated.

[0059]

[Catalyst Preparation Example 5] [Preparation of catalyst solution (e)] Thorough drying
With dropping funnel, condenser, gas inlet tube, stirrer
2 hours at 300 ° C in a 500ml inner volume flask
Calcined and further ground CsF (9 g, 59.2 mmol)
Was inserted. 220 ° C, 1mmH in this flask
and dried under reduced pressure for 1 hour. Next, at room temperature (20 ° C),
Traglyme (31.3 g) and F-CO-C (CF_Three) F-OCF_Two
CF_TwoO-CF (CF_Three) -CO-F (4.2 g, 19.86 mmol) was added dropwise.
Insert from the lower funnel. After dropping, mix at 30 ° C.
The mixture was stirred. Raw material FOC-CF (CF_Three) -OCF_TwoCF
_TwoO-CF (CF_Three) The presence of a terminal -COF group in -COF ¹⁹FN
The stirring was continued while confirming with MR, and the terminal -COF group disappeared.
At this point, the stirring was stopped. As it is at room temperature (20 ° C)
After resting overnight (about 12 hours), unreacted CsF
Removed. Further, the obtained reaction solution is mixed with the terminal -COF group.
The catalyst solution (e) was allowed to stand for a total of 24 hours after disappearance of
I got Polymerization initiator CsO-CF in the obtained catalyst solution (e)
_2-CF (CF_Three) -OCF_TwoCF_TwoO-CF (CF_Three) -CF_TwoThe concentration of -OCs is 2 × 1
0 ^-FourIt was calculated as mol / g. The molar ratio of FOCRfCOF and CsF (F
OCRfCOF: CsF) was calculated to be 1: 6.

[0060]

[Catalyst Preparation Example 6] [Preparation of catalyst solution (f)] The mixture was calcined at 300 ° C. for 2 hours in a sufficiently dried 500 ml flask equipped with a dropping funnel, a condenser, a gas inlet tube, and a stirrer, and further pulverized. CsF (9 g, 59.2 mmol)
Was inserted. 220 ° C, 1mmH in this flask
and dried under reduced pressure for 1 hour. Next, tetraglyme (31.3 g) and F-CO-C (CF ₃ ) F-OCF ₂ at room temperature (20 ° C.)
CF ₂ O—CF (CF ₃ ) —CO—F (10.5 g, 24.64 mmol) was inserted from the dropping funnel, and after completion of the dropping, at a temperature of 30 ° C.
The mixture was stirred. Raw material in reaction solution FOC-CF (CF ₃ ) -OCF _{2
CF 2 O-CF (CF 3} ) the presence of -COF group at the end of -COF ¹⁹ F-
The stirring was continued while confirming by NMR, and the stirring was stopped when the terminal -COF group disappeared. Room temperature (20 ° C)
After standing overnight (about 12 hours), unreacted CsF
Was removed. Further, the obtained reaction solution was mixed with the terminal-COF.
After the group disappeared, the mixture was allowed to stand for a total of 24 hours to obtain a catalyst solution (f). Polymerization initiator in the obtained catalyst solution (f)
_{CsO-CF 2- CF (CF 3} ) -OCF 2 CF 2 O-CF (CF 3) Concentration of -CF ₂ -OCs is
It was calculated to be 5 × 10 ^-4 mol / g. The molar ratio of FOCRfCOF to CsF (FOCRfCOF: CsF) was calculated to be 1: 2.4.

[0061]

Example 1 Into a 500 ml flask having a sufficiently dried internal volume, 4 parts of the catalyst solution (a) prepared in Catalyst Preparation Example 1 was added.
3.5 g (5 × 10 ⁻⁴ mol / g) were charged. Thereafter, 12 g of hexafluoropropylene (HFP) was supplied at room temperature, followed by stirring for 50 minutes.
And further supplied with 12 g of HFP. Hexafluoropropylene oxide (HFPO)
A mixed gas of 135 g and 87 g of HFP was added to a mixture of -35 to -32.
The injection was carried out at a temperature of ° C. for 17 hours. HFPO and H
After the supply of the mixed gas of FP was completed, the mixture was further stirred for 1 hour at the same temperature, and then heated to recover unreacted HFP.

[0062] 300 g of methanol was added to the obtained reaction solution.
88 g of CF ₂ ClCFCl ₂ was added and stirred for 30 minutes. The lower layer separated is separated and the volatile component is distilled off at 120 ° C./1 mmHg, and the bifunctional perfluoroether represented by the following formula (A) and the monofunctional represented by the following formula (B) 115 g of a liquid mixture with perfluoropolyether was obtained.

[0063]

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Table 1 shows the results of ¹⁹ F-NMR spectrum of this mixed liquid.

[0065]

[Table 1]

From the above measurement results, the average degree of polymerization was 38.8 and the selectivity (A) / (B) was 95/5, as described below. Average degree of polymerization = 2 m / (k + 0.5x) = 38.8 Selectivity = [100 (k-0.5x) / (k + 0.5x)] / [100x / (k + 0.5x)] = 95 /
Five

[0067]

Example 2 Into a 500 ml flask having a sufficiently dried inner volume, 3 parts of the catalyst solution (b) prepared in Catalyst Preparation Example 2 were added.
8.8 g (5 × 10 ⁻⁴ mol / g) were charged. Thereafter, 10 g of hexafluoropropylene (HFP) was supplied at room temperature, and the mixture was stirred for 40 minutes.
, And 11 g of HFP was further supplied. Hexafluoropropylene oxide (HFPO)
A mixed gas of 114 g and 65 g of HFP was added to a mixture of -35 to -32.
Injected at a temperature of ° C. over 20 hours. HFPO and H
After the supply of the mixed gas of FP was completed, the mixture was further stirred for 1 hour at the same temperature, and then heated to recover unreacted HFP.

The obtained reaction solution was mixed with 300 g of methanol,
88 g of CF ₂ ClCFCl ₂ was added and stirred for 30 minutes. The lower layer separated is separated and the volatile component is distilled off at 120 ° C./1 mmHg, and the bifunctional perfluoroether represented by the following formula (A) and the monofunctional represented by the following formula (B) 122 g of a liquid mixture with perfluoropolyether was obtained.

[0069]

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Table 2 shows the results of ¹⁹ F-NMR spectrum of this mixed liquid.

[0071]

[Table 2]

From the above measurement results, the average degree of polymerization was 40.7 and the selectivity (A) / (B) was 89/11, as described below. Average degree of polymerization = 2m / (k + 0.5x) = 40.7 Selectivity = [100 (k-0.5x) / (k + 0.5x)] / [100x / (k + 0.5x)] = 89 /
11

[0073]

Example 3 Into a 500 ml flask having a sufficiently dried inner volume, 2 parts of the catalyst solution (c) prepared in Catalyst Preparation Example 3 was added.
7.7 g (5 × 10 ⁻⁴ mol / g) were charged. Thereafter, 12 g of hexafluoropropylene (HFP) was supplied at room temperature, and the mixture was stirred for 60 minutes.
And further supplied with 12 g of HFP. Hexafluoropropylene oxide (HFPO)
A mixed gas of 92 g and 32 g of HFP was cooled to -35 to -32 ° C.
At a temperature of 14 hours. HFPO and HF
After the supply of the mixed gas of P was completed, the mixture was further stirred at the same temperature for one hour, and then heated to recover unreacted HFP.

The obtained reaction solution was mixed with 300 g of methanol,
70 g of CF ₂ ClCFCl ₂ was added and stirred for 30 minutes. The lower layer separated is separated and the volatile component is distilled off at 120 ° C./1 mmHg, and the bifunctional perfluoroether represented by the following formula (A) and the monofunctional represented by the following formula (B) 95 g of a liquid mixture with perfluoropolyether was obtained.

[0075]

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Table 3 shows the results of ¹⁹ F-NMR spectrum of this mixed liquid.

[0077]

[Table 3]

From the above measurement results, the average degree of polymerization was 42.7 and the selectivity (A) / (B) was 91/9, as described below. Average degree of polymerization = 2 m / (k + 0.5x) = 42.7 Selectivity = [100 (k-0.5x) / (k + 0.5x)] / [100x / (k + 0.5x)] = 91 /
9

[0079]

Example 4 Into a 500 ml flask having a sufficiently dried inner volume, 4 parts of the catalyst solution (d) prepared in Catalyst Preparation Example 4 was added.
2.5 g (5 × 10 ⁻⁴ mol / g) were charged. Thereafter, 12 g of hexafluoropropylene (HFP) was supplied at room temperature, and the mixture was stirred for 60 minutes.
And further supplied with 12 g of HFP. Hexafluoropropylene oxide (HFPO)
A mixed gas of 126 g and 91 g of HFP was added to a mixture of -35 to -32.
The injection was carried out at a temperature of ° C. for 26 hours. HFPO and H
After the supply of the mixed gas of FP was completed, the mixture was further stirred for 1 hour at the same temperature, and then heated to recover unreacted HFP.

The obtained reaction solution was mixed with 300 g of methanol,
88 g of CF ₂ ClCFCl ₂ was added and stirred for 30 minutes. The lower layer separated is separated and the volatile component is distilled off at 120 ° C./1 mmHg, and the bifunctional perfluoroether represented by the following formula (A) and the monofunctional represented by the following formula (B) 97 g of a liquid mixture with perfluoropolyether was obtained.

[0081]

Embedded image

Table 4 shows the results of ¹⁹ F-NMR spectrum of this mixed liquid.

[0083]

[Table 4]

From the above measurement results, the average degree of polymerization was 41.5 and the selectivity (A) / (B) was 92/8, as described below. Average degree of polymerization = 2 m / (k + 0.5x) = 41.5 Selectivity = [100 (k-0.5x) / (k + 0.5x)] / [100x / (k + 0.5x)] = 92 /
8

[0085]

Comparative Example 1 A catalyst solution (e) prepared in Catalyst Preparation Example 5 was charged into a sufficiently dried 500-ml flask with a volume of 13.0.
g (2 × 10 ⁻⁴ mol / g) and stirred at −35 ° C. for 15 minutes. Then, hexafluoropropylene (HF
P) After supplying 4 g, the mixture was stirred for 60 minutes, the resulting mixed solution was cooled to -38 ° C, and a mixed gas of 108 g of hexafluoropropylene oxide (HFPO) and 54 g of HFP was charged at a temperature of -38 to -32 ° C. Entered. About 30 minutes after the charging of the mixed gas was started, the reaction system solidified. No perfluoropolyether was obtained.

[0086]

Comparative Example 2 The catalyst solution (f) prepared in Catalyst Preparation Example 6 was placed in a sufficiently dried 500 ml flask having a capacity of 20.0 ml.
g (5 × 10 ⁻⁴ mol / g), cooled to −35 ° C.
Stir for 1 hour. Thereafter, 5 g of hexafluoropropylene (HFP) was supplied, and the mixture was stirred at that temperature for 20 minutes. To this solution, 85.7 g of hexafluoropropylene oxide (HFPO) and 100.8 g of a mixed gas of 15.1 g of HFP were charged over 13 hours at a temperature of −38 to −32 ° C. After the supply of the mixed gas of HFPO and HFP was completed, the mixture was further stirred at a temperature of −38 to −32 ° C. for 4 hours. After the reaction was completed, unreacted gas was distilled off under reduced pressure while cooling. Thereafter, 100 g of methanol was added to the obtained reaction solution, and the mixture was further stirred for 10 minutes.
The separated lower layer is separated, and volatile components are distilled off at 120 ° C./1 mmHg. The bifunctional perfluoroether represented by the formula (A) and the monofunctional represented by the formula (B) are removed. 42 g of a liquid mixture with perfluoropolyether was obtained.

[0087]

[Table 5]

From the above measurement results, the average degree of polymerization was 11, and the selectivity (A) / (B) was 51/49, as described below. Average degree of polymerization = 2m / (k + 0.5x) = 11 Selectivity = [100 (k-0.5x) / (k + 0.5x)] / [100x / (k + 0.5x)] = 51 /
49

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Grinevskaya Bella Constantinonya Moscow 113054 Davininskaya Estee. 38 / 40-G Apty. 52 F-term (reference) 4J005 AA09 BA00 BB02

Claims (9)

[Claims] [Claim 1] The following general formula [I] [In the formula [I], Rf is a perfluoroalkylene having 1 to 4 carbon atoms or a perfluoroalkylene having an ether bond having 2 to 10 carbon atoms, and x and y
Satisfy the relationship of x + y = 2 and 0.1 <y <2. Wherein a perfluoropolyether is obtained by polymerizing hexafluoropropylene oxide in the presence of a polymerization initiator-containing solution comprising a polymerization initiator (A) represented by the following formula: and an aprotic polar solvent. A method for producing perfluoropolyether. 2. The compound represented by the following general formula [II] wherein Rf in the general formula [I] is [In the formula [II], Rf ′ is a perfluoroalkylene having 2 to 6 carbon atoms, The method for producing perfluoropolyether according to claim 1, wherein 3. The method according to claim 1, wherein the polymerization of the hexafluoropropylene oxide is performed at −30 ° C. or lower. 4. The method according to claim 1, wherein the concentration of the polymerization initiator (A) in the solution containing the polymerization initiator is 4 × 10 ⁻⁴ mol / g or more. Production method of perfluoropolyether. 5. The method according to claim 1, wherein in the polymerization of the hexafluoropropylene oxide, hexafluoropropylene is further used in an amount of 20 to 50% by weight based on the hexafluoropropylene oxide. A process for producing a perfluoropolyether according to the above. 6. The polymerization initiator (A) is represented by the following general formula [III]: [In formula [III], Rf ″ represents a perfluoroalkylene group having 1 to 4 carbon atoms or a perfluoroalkylene group having an ether bond having 2 to 10 carbon atoms. ] Perfluorodicarboxylic acid fluoride (B)
The method for producing perfluoropolyether according to any one of claims 1 to 5, wherein the method is obtained by reacting CsF with CsF in an aprotic polar solvent. 7. The perfluorodicarboxylic acid fluoride (B) is represented by the following general formula [IV]: [In formula [IV], Rf ″ ′ represents a perfluoroalkylene group having 2 to 4 carbon atoms. The method for producing a perfluoropolyether according to claim 6, which is represented by the following formula: 8. The use ratio of the perfluorodicarboxylic acid fluoride (B) and the CsF (CsF / perfluorodicarboxylic acid fluoride (B) (molar ratio))
Is greater than or equal to 0.1 and less than 2.
Or the method for producing a perfluoropolyether according to 7. 9. The method for producing a perfluoropolyether according to claim 1, wherein the aprotic polar solvent is diglyme, triglyme, tetraglyme or sulfolane.