WO2004018413A1

WO2004018413A1 - Method of drying fluorinated 2-alkoxypropionic acid derivative

Info

Publication number: WO2004018413A1
Application number: PCT/JP2003/007590
Authority: WO
Inventors: Kenji Ishii; Noriyuki Shinoki; Takuya Arase
Original assignee: Daikin Industries, Ltd.
Priority date: 2002-06-14
Filing date: 2003-06-16
Publication date: 2004-03-04
Also published as: JP4013953B2; AU2003241665A1; JPWO2004018413A1

Abstract

A method of drying a fluorinated 2-alkoxypropionic acid derivative, comprising sequentially subjecting to drying step (1) and drying step (2) a fluorinated 2-alkoxypropionic acid derivative represented by the general formula: (I) (wherein A represents an alkoxy, etc.; X represents a halogen atom; Y1 and Y2 may be identical with or different from each other and represent a fluorine atom, etc.; n is an integer of 0 to 3; m is an integer of 1 to 5; and Z represents a hydrophilic group), characterized in that the drying step (1) is performed at 90˚C or below until a water content exceeding 0.3 mass% but not greater than 10 mass% is reached while the drying step (2) is performed at 100˚C or above until a water content of 0.2 mass% or less is reached.

Description

Method for drying fluorinated 2-alkoxypropionic acid derivatives

The present invention relates to a method for removing water from a mixture of a fluorinated 2-alkoxypropionic acid derivative and water without denaturing the fluorinated propionic acid derivative. Background art

Water-soluble fluorinated vinyl ethers having a terminal hydrophilic group can be used as such or after protecting the terminal hydrophilic group by fluorination or esterification or amidation / diimidation. It can be used to obtain a copolymer by polymerizing with a compound.

Since the obtained copolymer can have a salt-forming hydrophilic group, its use as an ion-exchange membrane in salt electrolysis, chemical sensors, separation membranes, fuel cells, etc. is being studied. It can be used as a polymer super-strong acid catalyst as it is, or for lithium batteries.

Conventionally, water-soluble fluorinated butyl ethers having a hydrophilic group at the terminal have been subjected to a neutralization reaction as described in U.S. Patent No. 3,560,568, International Patent Publication No. 98/43952, and pamphlets. A method is disclosed in which a mixture comprising the fluorine-containing 2-alkoxypropionic acid derivative obtained in the above and water is dried through a drying step.

However, the mixture of the fluorinated 2-alkoxypropionic acid derivative and water tends to generate by-products in the drying step, and the once-formed by-product is fluorinated 2-alkoxypropionic acid. Since it is a salt of an organic compound similar in properties to the derivative, it is difficult to separate and purify the fluorinated 2-alkoxypropionic acid derivative from by-products by ordinary distillation and recrystallization methods. There has been a need for a method for removing water without altering the 2-alkoxypropionic acid derivative. As a method of removing water from a mixture of a fluorinated 2-alkoxypropionic acid derivative, water, and water, a method using a hot-air drier, a rotary drier, or the like has been conventionally used. However, in this method, only the surface of the mixture is in a state of high viscosity, and There was a problem that the inside of the compound did not dry even if heated or rotated for a long time.

As a method for removing water from a mixture of a fluorinated 2-alkoxypropionic acid derivative and water, a method using a device capable of reducing pressure and stirring in addition to heating has been used in some cases. However, this method has problems that foaming occurs and the viscosity becomes extremely high and stirring becomes impossible. Summary of the Invention

In view of the above situation, an object of the present invention is to efficiently remove water from a mixture of a fluorinated 2-alkoxypropionic acid derivative and water without denaturing a fluorinated 2-alkoxypropionic acid derivative. ₀ near to provide a drying method that can

The present invention has the following general formula (I)

(In the formula, Α represents an alkoxyl group, a halogen atom, 1 OM ¹ or 1 OM ² _1/2 , M ¹ represents an alkali metal, a quaternary nitrogen or a hydrogen atom, and M ² represents an alkaline earth metal. X represents a halogen atom, Y ¹ and Y ² are the same or different and each represents a fluorine atom, an elementary silicon atom, a perfluoroalkyl group or a cyclofluoroalkyl group, and n represents an integer of 0 to 3. Y ¹ may be the same or different, m represents an integer of 1 to 5. m Y ² may be the same or different, and Z is A hydrophilic group.) A fluorine-containing 2-alkoxypropionic acid derivative (hereinafter, referred to as “compound (I)”) represented by) is subjected to a drying step (2) after the drying step (1), followed by drying. A method for drying a fluorine-containing 2-alkoxypropionic acid derivative, the method comprising: The step (1) is performed at 90 ° C. or less until the amount of water exceeds 0.3% by mass and equal to or less than 10% by mass. Perform at 100 ° C or more until the amount becomes less than mass% And a method for drying a fluorinated 2-alkoxypropionic acid derivative. Detailed Disclosure of the Invention

Hereinafter, the present invention will be described in detail.

The method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention is characterized by drying the above compound (I).

The compound (I) forms a mixture with water before being dried by the drying step (1) and the drying step (2) described below by the method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention. ing.

In the present specification, a mixture comprising the above compound (I) and water is referred to as "compound (I) mono-water mixture". The above “compound (I) mono-water mixture” is the one before the drying step (1), the one during the drying step (1), and the one before the drying step (2). It is a concept that includes things inside.

The compound (I) mono-water mixture may be a compound that is not dissolved in a liquid containing water as a main component of the compound (I), for example, an aqueous dispersion of the compound (I) or water. It may be an aqueous solution of the above compound (I) dissolved in a solvent containing as a main component.

When the compound (I) -one water mixture is, for example, A in the above general formula (I) is 1 OM ¹ or 1 OM ² _1/2 described later, it is dissolved in water or a solvent containing water as a main component. It may be an aqueous solution of the above compound (I), and preferably an aqueous solution of the above compound (I) dissolved in water.

The above-mentioned compound (I) mono-water mixture may be obtained by dissolving a low boiling organic solvent such as an alcohol which can be evaporated under the conditions in the method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention.

A in the general formula (I), an alkoxyl group, a halogen atom, is also one OM ¹ shows an OM ² _1/2.

The alkoxyl group is not particularly limited, and includes, for example, a methoxy group, an ethoxy group, a propoxy group, an isopropoxy group and the like.

The halogen atom is any one of a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. It may be.

M ¹ represents an alkali metal, a quaternary nitrogen or a hydrogen atom. The alkali metal may be any of Li, Na, K and Cs, but is preferably Na which is industrially inexpensive.

In the present specification, the above “quaternary nitrogen” is an atom consisting of a nitrogen atom and three groups to which this nitrogen atom is covalently bonded other than the oxygen atom [1 O—] in —OM ¹ described above. Group, wherein the group is an atomic group or an atom other than a hydrogen atom. The quaternary nitrogen is not particularly limited, and examples thereof include NRiRSRSR ⁴ (R \ R ² , R ³ and R ⁴ are the same or different and represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms). For example, a salt may be formed with a hydroxide ion or the like, or the salt may be in an ionized state.

M ¹ may be any of an alkali metal, a quaternary nitrogen or a hydrogen atom, but is preferably an alkali metal.

The M ² represents an alkaline earth metal. The alkaline earth metal may be any of Be, Mg, Ca and the like.

A is preferably ^one OM1 or _OM21 _/ ² . The compound (I), when in the above-mentioned A gar OM ¹ or one OM ² _1/2, when cormorants row pyrolysis below as a post-step, decarboxylation proceeds easily.

The above represents a halogen atom. X may be any of a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

Y ¹ and Y ² in the general formula (I) are the same or different and each represent a fluorine atom, a chlorine atom, a perfluoroalkyl group or a cyclofluoroalkyl group.

The above-mentioned perfluoroalkyl group is not particularly limited, and examples thereof include a trifluoromethyl group and a pentafluoroethyl group.

Said Y ¹ is preferably a triflate Ruo Russia methyl, said Y ² is preferably a fluorine atom.

N in the above general formula (I) represents an integer of 0 to 3. The n Y ¹ 's may be the same or different. In order to contain many hydrophilic groups per unit mass of the compound (I), n is preferably 0 or 1, and 0 More preferably, there is.

M in the above general formula (I) represents an integer of 1 to 5. the m Y ² may be different or may be identical der connexion. The larger m is, the stronger the strength as an acid is, but the number of hydrophilic groups per unit mass of the compound (I) is reduced. Therefore, the m is preferably 2.

Z in the general formula (I) represents a hydrophilic group.

The hydrophilic group, _COOM ^3, _COOM ⁴ _1/2, one OS_〇 ₃ M ^3, one S0 ₃ M ^3, one _{^{0 2 PM 3, -OP (OM}} 3) 2ヽone 0 ₂ P (OM ^3), _OPO (OM ³ ) ₂ , one P0 ₂ (OM ³ ), -PO (OM ³ ) ₂ , — OS0 ₃ M ⁴ _1/2 , — S0 ₃ M ⁴ _1/2 , -0 ₂ PM ⁴ _1/2 , -OP (OM ⁴ _1/2 ) ₂ , 0 ₂ P (OM ⁴ _1/2 ), --OPO (OM ⁴ _1/2 ) ₂ , -P 0 ₂ (OM ⁴ _1/2 ), 1 PO (OM ⁴ _1/2 ) _1/2 ) ₂ or a substituted anquinio group which forms a salt with a conjugate base of a mineral acid or a fatty acid (substituents are preferably 2 to 3 identical or different alkyl groups), and M ³ is , An alkali metal, the quaternary nitrogen or a hydrogen atom described above, and M ⁴ is preferably an alkaline earth metal.

The M ³ are, same as M ¹ described above, preferably an inexpensive N a for industrial, said M ³ are preferably the same kind of metal as the M ^1. The M ⁴ is preferably a metal of the same kind as the above M ^2.

The M ³ and M ⁴ in the case where the compound (I) is present as an aqueous solution, it is often present in a state of separated conductive.

In the present specification, the "substituent Anmoyuo group", and nitrogen atom, this nitrogen atom is engaged covalently binding to other sites represented by a (CFY ²⁾ _m _ in the above general formula (I) It means a group consisting of two or three identical or different alkyl groups. There are no particular restrictions regarding the aforementioned substituent Anmonio group, for example, one NR ⁵ R ⁶ H, one NR ⁵ R ⁶ (R ⁵ and R ⁶ are the same or different and represent an alkyl group.), And the like et be.

The substituted ammonium group forms a salt with a conjugate base of a monovalent or divalent or higher valent mineral acid or fatty acid. When the compound (I) exists as an aqueous solution, the conjugate base often exists in an ionized state from the substituted ammonium group. The mineral acid is not particularly limited, and examples thereof include hydrochloric acid, phosphoric acid, sulfuric acid, and nitric acid. The fatty acid is not particularly limited and includes, for example, formic acid, acetic acid, propionic acid and the like.

Z in the general formula (I) is preferably an S0 ₃ M ³ or one S0 ₃ M ⁴ _1/2.

In the method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention, as the compound (I), A is 1 OM ¹ or 1 OM ² _1/2 , Y ¹ is a trifluoromethyl group, It is a more preferable method when Y ² is a fluorine atom and m is 2.

In the method for drying a fluorinated 2-alkoxypropionic acid derivative according to the present invention, as the compound (I), A is one OM, M ¹ is Na, X is a fluorine atom, This is a more preferable method when n is 0, Y ² is a fluorine atom, m is 2, Z is —S 0 ₃ M ³ , and M ³ is Na.

The method for obtaining the above compound (I) is not particularly limited, and for example, known methods and the like can be used. Among the above compounds (I), for example, the following general formula

(Wherein, X, YY ² , η, m, Μ ¹ and Μ ³ are as described above).

(Wherein, Alpha ¹ represents an alkoxyl group or a halogen atom, Alpha ² represents a halogen atom. X, Υ \ Υ η and m are as defined above compound (I).) Are tables in Compound (a) is neutralized or saponified using a neutralizing reagent. You.

The above compound (a) can be produced by a conventionally known method. By reacting sulfur trioxide with tetrafluoroethylene [TFE], the following formula is obtained.

Is preferably obtained by obtaining a cycloadduct represented by the following formula, reacting with fluoride ion, and then reacting with hexafluoropropylene oxide [HFPO].

The neutralizing reagent is not particularly limited as long as it is a base, but is preferably an alkali metal hydroxide, and particularly preferably industrially inexpensive NaOH. The neutralizing reagent is usually used after being dissolved in a solvent for the neutralizing reagent. The solvent for the neutralizing reagent is usually water and Z or a water-soluble organic solvent, and water and alcohol are preferable. The neutralization is preferably performed using at least 4 equivalents of an alkali metal hydroxide per 1 mol of the compound (a). When the amount of the neutralizing reagent is less than 4 equivalents relative to 1 mol of the compound (a), all of the S0 ₂ A ² groups of the compound (a) do not become one S0 ₃ M ³ group. When n is 0 in the general formula for the compound (a), a cyclic by-product may be generated during the subsequent thermal decomposition. Although there is no particular problem if the amount of the neutralizing reagent is too large, it is industrially disadvantageous. Therefore, it is preferable that the neutralizing reagent be as small as possible within the above range.

The neutralization is performed by reacting at a temperature of 90 ° C. or lower for 1 to 48 hours in the presence of the neutralizing reagent. If the neutralization temperature exceeds 90 ° C., the compound (I) may be thermally decomposed. A preferred lower limit is 0 ° C, and a preferred upper limit is 80 ° C. If the reaction time of the neutralization is less than 1 hour, the neutralization may be insufficient. If the reaction time exceeds 48 hours, the neutralization reaction reaches an equilibrium state and the reaction does not proceed. The preferred lower limit is 3 hours and the preferred upper limit is 24 hours. In the above neutralization, the reaction rate of conversion from one SO ₂ A ² group to one S0 ₃ M ³ salt It is preferable to continue stirring for several hours after the neutralization reaction system changes to neutral. Thereafter, if the neutralization reaction system has changed to acidic, it is preferable to adjust the neutralization reaction system to be neutral by adding a neutralization reagent.

At the time of the neutralization, there is a possibility that hydrogen fluoride that cannot be completely neutralized may be generated. Therefore, it is preferable to use a reactor having corrosion resistance. In addition, since the heat generated by the neutralization is severe, it is desirable to perform the neutralization while cooling the reactor.

When the compound (I) is obtained by the above-mentioned neutralization or saponification, it is obtained as a mixture of water in which the above-mentioned neutralization reagent is dissolved and water generated by the neutralization. In the present invention, the compound (I) may be used as an aqueous solution as long as it is a mixture with water before drying, regardless of whether the compound (I) is formed through the above-described neutralization or saponification. It may be present or may not be dissolved in a liquid containing water as a main component.

The method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention is characterized in that the compound (I) is dried by performing a drying step (2) after the drying step (1).

In the present specification, the term "drying the compound (I)" means removing water from a mixture of the compound (I) and water.

The drying step (1) is performed at 90 ° C or less until the water content exceeds 0.3% by mass and is 10% by mass or less. When water is left in an amount exceeding 10 mass ° / ₀ and left at a temperature exceeding 90 ° C, for example, at a temperature of 100 ° C or more for a long time, the above compound (I) has the following general formula

(Wherein, X, YY ² , n, m and Ζ are as defined in the above compound (I)).

In the present specification, “water” in the drying step (1) and the drying step (2) described later means the amount of water in the compound (I) -one water mixture. The drying step (1) is preferably performed at 60 ° C. or higher as long as the temperature is within the above range. If the temperature is lower than 60 ° C, drying may take a long time.

Since the compound (I) has high hygroscopicity, the drying step (1) is more preferably performed at a temperature of 70 ° C. or higher as long as the temperature is within the above range from the viewpoint of efficient drying. .

The drying time in the drying step (1) is preferably several seconds to 50 hours, although it depends on the drying temperature, the air volume during drying, the charged amount, and the like. If it exceeds 50 hours, it is not preferable in terms of economy.

In the drying step (1), it is preferable that the temperature is further lowered in order to precipitate a solid. The solid is mainly composed of the compound (I). The temperature is preferably lowered by 1 ° C. or more from the temperature before the temperature lowering, and more preferably to a temperature at which the solid precipitates.

In the process of performing the drying step (1), the surface during which the drying of the compound (I) monohydrate mixture contained in the container or the like is to be performed is referred to as “on the way”, which is the time to perform the cooling. The state of high viscosity is preferable, and the “state of high viscosity” is, for example, a state in which fluidity is extremely reduced. When the surface of the compound (I) mono-aqueous mixture has a high viscosity, if the temperature is lowered to a temperature at which a solid precipitates, the water evaporates from the gap between the solids, so It can be dried. When drying is performed at a constant temperature, the surface of the above-mentioned compound (I) mono-water mixture is in a high-viscosity state, and no solid is formed, so the inside may not be dried.

After the cooling, the temperature is preferably returned to the temperature before the cooling and drying is continued. The process of once lowering the temperature and then raising it again may be repeated. The method for lowering the temperature is not particularly limited, and examples thereof include a method of taking out from a dryer and the like.

In the drying step (1), it is preferable to further perform mechanical pulverization of the precipitated solid and / or stirring of the compound (I) -aqueous mixture whose surface has a high viscosity. The compound having a high water content is obtained by mechanically pulverizing the surface of the above-mentioned compound (I) mono-aqueous mixture from which a solid is precipitated and stirring the mixture or stirring the above-mentioned compound (I) mono-aqueous mixture having a high viscosity. (I) The above compound (I) It can be exposed on the surface of an object to promote the evaporation of water. The solid on the surface may be cracked by cooling, the solid may be cracked by mechanical force, or both may be used in combination.

The above-mentioned grinding and the above-mentioned stirring may be carried out by a human using a spatula or the like, or a mixer such as a mixer with a conical screw capable of heating and flowing moisture and having a stirrer therein, a kind of kneader, etc. May be used.

The solid deposited on the container wall surface due to the above-mentioned temperature drop may be scraped off.

The drying step (2) is performed at a temperature of 100 ° C. or more until the water content becomes 0.2% by mass or less. When the temperature is lower than 100 ° C, the above compound (I) has a high hygroscopicity, so the water content is 0.2 mass. It is difficult to make it less than / ₀ . A more preferred lower limit is 110 ° C. A preferred upper limit is 200 ° C. When the temperature exceeds 200 ° C, the compound (I) is easily decomposed.

The drying time in the drying step (2) depends on the drying temperature, but is preferably several seconds to 20 hours. Exceeding 20 hours is not preferable in terms of economy. The dryer used in the drying step (1) and the drying step (2) is not particularly limited, and includes, for example, a circulating hot air dryer, an infrared dryer, a vacuum dryer, a rotary dryer, a dryer with a stirrer, Spray dryers and the like can be mentioned. However, care should be taken when drying the above compound (I) with the above vacuum dryer because foaming may occur because the above compound (I) has a surfactant-like molecular structure. .

When the compound (I) is to be dried by the hot air circulating dryer or the rotary dryer, the surface of the compound (I) -one water mixture becomes a high viscosity state in the drying step (1), (I) Since the inside of the one-water mixture may not be sufficiently dried, it is preferable to perform the above-mentioned temperature lowering or stirring.

The method for drying a fluorinated 2-alkoxypropionic acid derivative according to the present invention is characterized in that drying is performed in two stages of the drying step (1) and the drying step (2). In the above drying step (1), it is difficult to reduce the water content to 3% by mass or less, for example, 0.2% by mass or less, even if dried for a long time at a temperature of 90 ° C or less, for example, 80 ° C. However, following the drying step (1), in the drying step (2), the water content is increased by raising the temperature to a temperature of 100 ° C. or higher, preferably 110 ° C. to 200 ° C. Efficient drying in a relatively short time until is reduced to 0.1% by mass or less be able to.

The compound (I) is dried using the method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention, and then thermally decomposed by heating, for example, to form a water-soluble fluorinated butyl ether such as sodium butyl ether sulfonate. Generate When A in the above general formula (I) representing the above-mentioned fluorinated 2-alkoxypropionic acid derivative is 1 OM ¹ or 1 OM ² _1/2 , the organic solvent (A) is converted into the above-mentioned fluorinated 2-alkoxypropionic acid derivative. —Also present in an amount of 10 to 100 parts by mass, more preferably 30 to 300 parts by mass, based on 100 parts by mass of the alkoxypropionic acid derivative, at least 70 ° C. and 170 ° C. . It is preferably carried out at a temperature below C, more preferably below 150 ° C. The reaction time of the thermal decomposition depends on the temperature at which the thermal decomposition is performed, but is preferably 10 to 600 minutes after the reaction temperature is reached. If the reaction time is less than 10 minutes, thermal decomposition may be insufficient. A more preferred lower limit is 30 minutes, and a more preferred upper limit is 300 minutes.

The organic solvent (A) is an organic solvent having a coordinating ability to the alkali metal or alkaline earth metal ion of the fluorinated 2-alkoxypropionic acid derivative. As the organic solvent (A), a solvent comprising an aprotic organic polar solvent is preferable.

Examples of the aprotic organic polar solvent include ether solvents, sulfolane, hexamethylphosphoric triamide, acetonitrile, dimethylformamide, dimethylsulfoxide, tetramethylurea, and the like. A glyme solvent is preferred. And diethylene glycol dimethyl ether is more preferred.

By the above thermal decomposition, the following general formula (II)

A water-soluble fluorinated vinyl ether such as a fluorinated sulfoalkyl bier ether represented by the following formula is obtained. After the thermal decomposition, the water-soluble fluorinated vinyl ether forms a mixture with the organic solvent (A) and the inorganic salt. The inorganic salt is formed by the thermal decomposition It is a by-product generated, and examples thereof include sodium fluoride, potassium fluoride, and cesium fluoride. Therefore, the water-soluble fluorinated bier ether is preferably purified so as to remove the organic solvent (A) and the inorganic salt. When the above-mentioned inorganic salt is sodium fluoride, the above-mentioned purification can be preferably applied. In the above-mentioned purification, the above-mentioned water-soluble fluorine-containing ether is mixed with an organic solvent (B) by mixing an aqueous solution comprising the above-mentioned organic solvent (A) and an inorganic salt to remove the above-mentioned organic solvent (A). , And the mixture obtained by the first purification is mixed with an organic solvent (C) and the inorganic salt is separated by filtration (hereinafter, referred to as "second purification"). It is preferable to perform this. The organic solvent (B) is separated into two phases when mixed with an equal amount of water at 25 ° C, and is an organic solvent in which the solubility of the water-soluble fluorinated vinyl ether is 10% by mass or less. Yes, for example, those having a relative dielectric constant of 4 to 10 are preferable. The organic solvent (C) is an organic solvent that does not dissolve the inorganic salt but dissolves the water-soluble fluorinated butyl ether, and includes, for example, ketones such as acetone; esters such as ethyl acetate; Alcohols are preferred. The amount of the organic solvent (C) depends on the solubility of the mixture of the water-soluble fluorinated beer ether and the inorganic salt in the organic solvent (C). Preferably it is ~ 100 parts by weight. A more preferred lower limit is 500 parts by weight, and a more preferred upper limit is 500 parts by weight.

In the purification of the water-soluble fluorinated vinyl ether, it is preferable to perform drying during the purification after the first purification. By performing the drying during the purification, the crystals of the inorganic salt can be grown, and the second purification can be facilitated.

In the purification of the water-soluble fluorinated vinyl ether, it is preferable that after the second purification, drying is performed during the purification to remove the organic solvent (C).

The drying at the time of each purification is preferably performed at a drying temperature of 25 to 200 ° C. The water-soluble fluorinated bierether obtained by the above thermal decomposition can be used as it is or after the terminal hydrophilic group is protected by fluorination or esterification or amidation / imidation, as a monomer. It can be used to obtain a copolymer with an olefin such as yne.

The water-soluble fluorinated vinyl ether is chlorinated after the purification, It is preferable to obtain a fluorine-containing vinyl ether having a black end and fluorinating the same to obtain a fluorine-containing vinyl ether having a fluorine terminal. The chlorination is preferably performed by reacting the water-soluble fluorinated vinyl ether with a chlorinating reagent. There are no particular restrictions regarding the chlorinating reagent, for example, it includes _{_{PC 1 5, PC 1 3,}} S0 2 C 1 or the like, PC 1 ₅ is preferred. PC 1 ₅ for use as the chlorinating reagent, it is preferable to use the water-soluble fluorine-containing vinyl ether 1 mol per 1 equivalent or more. The fluorinated vinyl ether having a chloro terminal obtained by performing the above chlorination can be fluorinated by reacting with a conventionally known method, for example, NaF, KF or the like in a sulfolane solvent.

The copolymer of the water-soluble fluorinated vinyl ether obtained by the above-mentioned thermal decomposition and an olefin such as fluoroolefin is suitably used for ion exchange membranes, catalysts, lithium batteries and the like. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Production Example 1

Synthesis of fluorinated 2-alkoxypropionic acid derivatives

1.1) in 6 liters glass-lined pressure-resistant Otokureipu of monkey fan (Nissokinzokukagaku Inc.) from freshly placed distilled S0 ₃ (2 liters), after displacement purge between internal air with pure nitrogen gas, When tetrafluoroethylene was injected, the exothermic reaction started immediately, so the reaction was continued while adjusting the temperature to 40 to 60 ° C and the pressure to 0.1 to 0.2 MPa. After 40 minutes, the amount of the product increased to 5.2 liters, and when the absorption of tetrafluoroethylene no longer occurred, the reaction was stopped by cooling. The reaction was a clear, colorless liquid which was found by distillation to be almost pure tetrafluoroethane-sultone.

1.2) 400 g of potassium fluoride dried at 300 ° C for 10 minutes is placed in a 6-liter glass-lined pressure-resistant auto tare, sealed immediately under a nitrogen stream, and then Then, diethylenedalicol dimethyl ether (1 liter) was added thereto, and tetrafluoroethane J3-sulfone (1 liter) obtained in step 1.1) was gradually added dropwise. Markedly correct an exothermic reaction, the free 30 ₂ 〇 ₂ 〇 ₂ 011 but also observed generation of, be complete almost isomerization reaction to quantitatively FS_〇 ₂ CF ₂ COF is the ¹⁹ F- NM R confirmed.

1.3) Step 1. The same reactor used as that used in 2), the hexa full O b propylene O wherein de [HFPO] gas to = 25 ° C in the FS 0 ₂ CF ₂ COF produced under the same conditions When the pressure was increased to 0.2 MPa, an exothermic reaction started immediately. Therefore, the reaction was continued for 3 hours under a pressure of 1 to 0.2 MPa while adjusting the temperature to 20 to 40 ° C. After that, the reaction was interrupted and the residual gas was released because the pressure drop rate became low. The volume of the product in 2.7 Rittonore, the product made from the lower phase of a yellow upper phase and a colorless, according to distillation, 90 volume% of the product that one adduct of HF PO following compound F S0 ₂ CF ₂ CF ₂ OCF (CF ₃ ) COF

, And the generation of Wazukani FS0 ₂ CF ₂ COF and 2 adduct was observed.

1.4) Neutralize the compound obtained in step 1.3) with a 20% by mass aqueous sodium hydroxide solution to quantitatively determine the following compound U)

Na S0 ₃ CF ₂ CF ₂ OCF (CF ₃ ) COON a

A 36% by mass aqueous solution of a fluorinated 2-alkoxypropionic acid derivative represented by the following formula was obtained. Example 1

4 kg of a 36% by mass aqueous solution of the above-mentioned fluorinated 2-alkoxypropionic acid derivative was placed in a 35 Omm X 45 Omm vat, and charged into a hot air circulating drier maintained at 80 ° C. After 12 hours, the surface became highly viscous, so the vat was once removed and cooled to around 25 ° C. When the surface crystallized and became opaque, it was stirred with a spatula. The powder was again put into a hot air circulating drier at 80 ° C and dried for 24 hours to obtain powder A. The powder A (1 g) was dispersed in 14 g of ethylene glycol dimethyl ether, the supernatant was measured by Karl Fischer titration, and the water content in ethylene glycol dimethyl ether measured separately was subtracted. Powder water The minute was 0.5% by mass.

Powder A (1.2 kg) obtained by drying the above compound (i) at 80 ° C for 36 hours is further charged into a hot air circulating drier maintained at 120 ° C, and dried for 12 hours. I got body B. Thereafter, the water content of the powder B was measured by the same method as that for the powder A, and it was 0.1% by mass. The compound obtained by a two-step drying process as described above the powder (i) was dissolved in water, ¹⁹ F- was measured NMR (reference material: CFC 1 ₃₎ between the roller, the compound (i one _{C (O) CF1 (CF 3} ) O- underlined from fluorine atom of δ = _ 1 26. 5 p pm near the peak and the following compound _{_{in) (ii) CF 3 CFHOCF 2}} CF 2 S0 3 Na

From the area ratio of the underlined CF ₃ C! HO—fluorine atom-derived δ = -145.5 peak in the decomposition product of the above compound (ii), it was concluded that the compound (ii) was not formed at all. I was assured. Comparative Example 1

120 Drying was performed in the same manner as in Example 1 except that drying at 20 ° C. was omitted, and the water content was measured in the same manner as in Example 1. The water content of the powder of the compound (i) was 0.5% by mass, and it was confirmed that the compound (ii) was not formed at all. Comparative Example 2

200 g of an aqueous solution containing 36% by mass of the above compound (i) was placed in a 300-milliliter viscous solution, dried at 80 ° C for 64 hours without stirring at all, and water was removed in the same manner as in Example 1. As a result of the measurement, the water content was 0.9% by mass, and it was confirmed that the compound (ii) was not formed at all. Comparative Example 3

200 g of an aqueous solution containing 36% by mass of the above compound (i) was placed in a 300-mL viscous solution, dried at 130 ° C. for 6 hours without stirring at all, and the water content was measured in the same manner as in Example 1. However, the water content was 0.1% by mass, but the compound (ii) contained 13 mol%. Comparative Example 4

In Example 1, after drying at 80 ° C for 12 hours and stirring at 80 ° C, the whole became a syrup. The resultant was further dried for 24 hours, and the water content was measured in the same manner as in Example 1. The water content was 0.8% by mass, and it was confirmed that the compound (ii) was not formed at all. Reference Example 1 (The thermal decomposition of a fluorinated 2-alkoxypropionic acid derivative and the purification of the water-soluble fluorinated butyl ether obtained by this thermal decomposition)

Glass vessel 20 liters equipped with a stirrer, a N AOC obtained in Example _{1 (O) CF (CF 3} ) OCF 2 CF 2 S0 3 N a (6. 4 kg), diethylene glycol dimethyl ether ( 6 liters, 85 parts by mass based on 100 parts by mass of the above-mentioned fluorinated 2-alkoxypropionic acid derivative). Was subjected to heating with a mantle heater, the internal temperature Rei_0 ₂ occurs from the time it reaches the 1 00 ° C. Thereafter, the temperature was gradually increased until the internal temperature reached 140 ° C. After heating for 180 minutes, generation of C0 ₂ ceased, so heating was stopped.

After the completion of the reaction, lowering the internal temperature to 90 ° C, to distill off the 2. reduced to 0 X 10 ³ P a di ethyleneglycidyl comb dimethyl ether (3 liters). 6 liters of pure water was added to the obtained reaction solution to dissolve it, and furthermore, porcelain form (6 liters) was added and stirred. The solution was allowed to stand, and when the liquid level was clearly separated, the lower layer was extracted. The operations of charging, stirring and withdrawing the outlet form were repeated seven times, and the obtained aqueous solution was put in a bag, and put in a hot-air circulating drier kept at 80 ° C for 12 hours to obtain a powder. The obtained powder was dissolved in 6 liters of acetone and filtered. The filtrate was dried on a rotary evaporator at 80 ° C. to obtain CF ₂ = CFOCF ₂ CF ₂ SO ₃ Na (5.2 kg). Reference Example 2 (Chlorination and fluorination of terminal group of water-soluble fluorine-containing vinyl ether) · A 10 liter glass container equipped with a stirrer was heated to 50 ° C, and CF ₂ = CFOCF ₂ CF ₂ S0 ₃ Na (4.6 kg) and PC 1 ₅ (6.8 kg And) were alternately added little by little. Hydrochloric acid gas was generated vigorously during the charging. After charging was completed, a distillation apparatus was attached, and a fraction at around 105 ° C was extracted. The obtained fraction was dropped into 3 liters of cold water, the lower part of the liquid separated into two phases was extracted, and CF ₂ = C

The FOCF _₂ CF ₂ S_〇 ₂ C l to give 3. 3 kg.

In a 5 liter glass vessel equipped with a stirrer and five rectification columns, the obtained CF ₂ =

3.3 kg of CF0CF ₂ CF ₂ S0 ₂ C 1, 1.9 kg of sulfolane, Na F

1.Introduce 3 kg, heat and extract a fraction at around 75 ° C, CF ₂ = CF〇

2.8 kg of CF ₂ CF ₂ SO ₂ F was obtained. The yield based on the fluorinated 2-alkoxypropionic acid derivative was 58%.

Reference example 3

Compounds containing water obtained in Comparative Example 1 0.5% by weight of (i) was allowed to pyrolysis in the same manner as in Reference Example _{_{1, CF 2 = CFOCF 2 CF}} 2 S_〇 ₃ Na is 43 mol ⁰ _{_{_{/ 0, CF 3 CFHOCF 2 CF}}} 2 S0 3 Na was obtained in a proportion of 57 mol ^_0/0. Industrial applicability

Since the method for drying a fluorinated 2-alkoxypropionic acid derivative of the present invention has the above-described configuration, water can be efficiently removed without altering the fluorinated 2-alkoxypropionic acid derivative.

Claims

The scope of the claims

1. The following general formula (I)

(Wherein, Alpha represents an alkoxyl group, a halogen atom, an OM ¹ or one OM ² _1/2, M ¹ represents an alkali metal, quaternary nitrogen or a hydrogen atom, M ² is an alkaline earth metal. X represents a halogen atom, Y ¹ and Y ² are the same or different and each represents a fluorine atom, a chlorine atom, a perfluoroalkyl group or a chlorofluoroalkyl group, and n represents an integer of 0 to 3. n Y ¹ may be the same or different, m represents an integer of 1 to 5. m Y ² may be the same or different. A hydrophilic group.) A fluorine-containing 2-alkoxypropionic acid derivative obtained by drying a fluorine-containing 2-alkoxypropionic acid derivative represented by the formula (1) followed by a drying step (2) A derivative drying method,

The drying step (1) is performed at 90 ° C. or less until the amount of water exceeds 0.3% by mass and 10% by mass or less,

The drying step (2) is performed at 100 ° C. or more until the water content becomes 0.2% by mass or less.

A method for drying a fluorinated 2-alkoxypropionic acid derivative.

2. hydrophilic ^{_{groups, - COOM 3, -OS0 3 M}} 3, one _{^{_{S0 3 M 3, - 0 2}}} PM 3, - OP (OM 3) 2, -0 2 P (OM 3), one OPO (OM ³ ) ₂ , -P0 ₂ (OM ³ ), -PO (OM ³ ) ₂ , one COOM ⁴ _1/2 , one OS0 ₃ M ⁴ _1/2 , one S0 ₃ M ⁴ _1/2ヽ one 0 ₂ PM ⁴ _{1 / 2} , —OP (OM ⁴ _1/2 ) ₂ , one O ₂ P (OM ⁴ _1/2 ), —OPO (OM ⁴ 1/2) 2, one PO2 O! I _1/2 ), one PO ( OM ⁴ _1/2 ) ₂ or a substituted ammonium group which forms a salt with a conjugate base of a mineral acid or a fatty acid (substituents are 2 to 3 identical or different alkyl groups), and M ³ is Alkali metal, quaternary nitrogen or water 2. The method for drying a fluorine-containing 2-alkoxypropionic acid derivative according to claim 1, wherein the element is a hydrogen atom, and M ⁴ is an alkaline earth metal.

3. The method for drying a fluorinated 2-alkoxypropionic acid derivative according to claim 1 or 2, wherein the drying step (1) further comprises mechanical pulverization.

4. The method for drying a fluorinated 2-alkoxypropionic acid derivative according to claim 1, 2, or 3, wherein the drying step (1) further comprises lowering the temperature in order to precipitate a solid.

5. The method for drying a fluorinated 2-alkoxypropionic acid derivative according to claim 1, wherein n is 0 or 1.

6. hydrophilic groups, over S0 ₃ M ³ or _S0 ₃ M ⁴ _1/2 Dearu claims second, 4 or 5, wherein the fluorine-containing 2-alkoxypropionic acid derivative drying method described.

7. A is — OM ¹ or 1 OM ² _1/2 , Y ¹ is a trifluoromethyl group, Y ² is a fluorine atom, and m is 2. The method for drying a fluorine-containing 2-alkoxypropionic acid derivative according to the above item.

8. The method for drying a fluorine-containing 2-alkoxypropionic acid derivative according to claim 7, wherein n is 0.