JP6107452B2 - Method for producing partially fluorinated dioxolane, method for producing dioxole, and method for producing electrolyte - Google Patents

Description

  The present invention relates to a method for producing partially fluorinated dioxolane, a method for producing dioxole, and a method for producing an electrolyte. More specifically, the present invention relates to producing dioxole such as perfluoro-2,2-dimethyldioxole (PDD). A method for producing partially fluorinated dioxolane that can be produced at low cost as a partially fluorinated dioxolane used as a raw material of the present invention, a method for producing dioxole using the partially fluorinated dioxolane obtained by this method, and an electrolyte It relates to a manufacturing method.

  The light transmission material uses an optical fiber having high light transmittance and a high refractive index as a core material to transmit information. The coating agent on the surface of building materials improves weather resistance by imparting high oil repellency and water repellency to prevent surface contamination. A secondary battery is composed of a negative electrode, a positive electrode, a separator, and an electrolytic solution. In order to suppress deterioration of the electrolytic solution, an additive for forming an oxide film on the surface of the negative electrode material has been developed. In a polymer electrolyte fuel cell, a membrane electrode assembly (MEA) in which an electrolyte membrane and an electrode (a mixture of a catalyst and a catalyst layer ionomer) are joined is used as a basic unit, and power is generated by a reaction between protons and oxygen.

  Since fluorine has a high electron-withdrawing property and strong carbon-fluorine bond energy, fluorine-based low molecules and polymers are used to realize the above materials. Lucina (registered trademark, manufactured by Asahi Glass Co., Ltd.) with excellent light transmittance, Cytop (registered trademark, manufactured by Asahi Glass Co., Ltd.) with excellent weather resistance and solubility, and fluoroethylene carbonate for forming an oxide film on the negative electrode surface And Nafion (registered trademark, manufactured by DuPont) and Flemion (registered trademark, manufactured by Asahi Glass Co., Ltd.), which are excellent in high proton conductivity and oxidation resistance. These compounds are excellent in light transmittance, oxidation resistance, weather resistance, proton conductivity and the like, but are generally expensive.

  However, there are still problems to be solved in order to use these widely. For example, if it is used as a weather-resistant paint, it is a method of introducing a fluorine-based substituent selectively in one step if it is soluble in a solvent and reducing the cost, and if it is an oxide film material for a secondary battery. In addition, for the spread of fuel cell vehicles, a means for reducing the cost by reducing the amount of Pt used for the catalyst is necessary. To achieve this, it is necessary to develop a catalyst layer ionomer with high proton conductivity and high oxygen permeability.

Conventionally, various proposals have been made to provide such various materials reliably, stably and safely.
For example, with respect to a method for producing an electrode ionomer for a fuel cell, Patent Document 1 describes a method in which hexafluoroacetone (HFA) and ethylene oxide are reacted to obtain bistrifluoromethyldioxolane (BTD).
Non-Patent Document 1 describes a method for producing a compound having a structure similar to BTD by reacting 2-chloroethyl trifluoroacetate, tetrafluoroethylene (TFE), and F anion.

Patent Document 2 describes a method for producing BTD in which hexafluoroacetone and 2-chlorohydrin are reacted and then the reaction product is alkali-treated.
Non-Patent Document 2 includes
(A) a method of reacting (trifluoromethyl) trimethylsilane (TMSCF ₃ ) with tributylammonium fluoride (TBAF) or CsF to generate a CF ₃ anion, and
(B) A method of obtaining a silylated hemiketal by reacting the generated CF ₃ anion with a partially fluorinated ester is disclosed.

Non-Patent Document 3 discloses a method in which trifluoromethane (CF ₃ H) is reacted with hexamethyldisilazane potassium (KHMDS) to generate a CF ₃ anion.
Furthermore, Non-Patent Document 4 describes a method of reacting CF ₃ CO ₂ CH ₃ with a nucleophile. This document describes that the ketal structure can be stably isolated by such a method.

  When BTD is used as a starting material, perfluoro-2,2-dimethyldioxole (PDD) can be synthesized. Since PDD is vinyl ether, an electrolyte polymer can be synthesized by copolymerizing with an electrolyte monomer having a vinyl group. It has been found that an electrolyte polymer containing PDD has high oxygen permeability, and when this is used for a fuel cell catalyst layer, the cell performance is remarkably improved even with a low Pt amount. However, the cost of this electrolyte polymer is high, which is a problem in the spread of fuel cell vehicles.

US Pat. No. 3,324,145 Japanese Patent Laid-Open No. 06-092957

Macromolecules 1993, 26, 5829 J. Org. Chem. 1991, 56, 984 Science 2012, 338, 1324 J. Org. Chem. 1987, 52, 5026

The problem to be solved by the present invention is to provide a method for producing partially fluorinated dioxolane, which can produce partially fluorinated dioxolane used as a raw material for producing dioxole such as PDD at low cost.
Another object of the present invention is to provide a method for producing dioxole using a partially fluorinated dioxolane obtained by such a method, and a method for producing an electrolyte.

In order to solve the above problems, a method for producing a partially fluorinated dioxolane according to the present invention comprises:
(1) and a partially fluorinated ester having a leaving group X ₁ having the structure represented by the formula, CF ₃ ^- is reacted with a partially fluorinated dioxolane having the structure represented by the formula (2) The gist is that the reaction step is obtained.

但し、
Ｒ ₁ は、炭素数１以上１０以下のパーフルオロアルキル基、
ｎは、１以上５以下の整数、
各Ｒは、それぞれ、水素、炭素数１以上１０以下のアルキル基、又は、アリール基、
Ｘ₁は、Ｃｌ、Ｂｒ、Ｉ、トシラート、メシラート、又は、トリフラート。

However,
R ₁ is a perfluoroalkyl group having 1 to 10 carbon atoms,
n is an integer of 1 to 5,
Each R is hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aryl group,
X ₁ is Cl, Br, I, tosylate, mesylate or triflate.

The method for producing dioxole according to the present invention comprises a step of obtaining a partially fluorinated dioxolane by the method according to the present invention and producing dioxolol using the partially fluorinated dioxolane.
Furthermore, the method for producing an electrolyte according to the present invention includes a step of obtaining dioxole by the method according to the present invention and producing an electrolyte using the dioxole.

  The partially fluorinated ester represented by the formula (1) is less expensive than HFA. Therefore, when this is used as a starting material, a partially fluorinated dioxolane such as BTD can be produced at a low cost. When the partially fluorinated dioxolane thus obtained is used as a starting material, dioxole and an electrolyte polymer using the dioxole can be produced at low cost.

Hereinafter, an embodiment of the present invention will be described in detail.
[1. Method for producing partially fluorinated dioxolane]
The process for producing a partially fluorinated dioxolane according to the present invention comprises:
(1) A partially fluorinated dioxolane having a structure represented by the formula (2) is prepared by reacting a partially fluorinated ester having a leaving group X ₁ having a structure represented by the formula with an R ₂ anion. The reaction process to obtain is provided.

但し、
Ｒ₁、Ｒ₂は、それぞれ、（ｉ）炭素数１以上１０以下のアルキル基、部分フッ素化アルキル基若しくはパーフルオロアルキル基、又は、（ｉｉ）アリール基、
Ｒ₁及びＲ₂の少なくとも一方は、付け根部分の炭素に結合している水素の少なくとも１つがフッ素原子に置換されている部分フッ素化アルキル基又はパーフルオロアルキル基、
ｎは、１以上５以下の整数、
各Ｒは、それぞれ、水素、炭素数１以上１０以下のアルキル基、又は、アリール基、
Ｘ₁は、Ｃｌ、Ｂｒ、Ｉ、トシラート（ｐ−トルエンスルホニル基）、メシラート、又は、トリフラート（トリフルオロメタンスルホナート）。

However,
R ₁ and R ₂ are each (i) an alkyl group having 1 to 10 carbon atoms, a partially fluorinated alkyl group or a perfluoroalkyl group, or (ii) an aryl group,
At least one of R ₁ and R ₂ is a partially fluorinated alkyl group or a perfluoroalkyl group in which at least one of hydrogen bonded to the carbon of the base portion is substituted with a fluorine atom;
n is an integer of 1 to 5,
Each R is hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aryl group,
X ₁ is Cl, Br, I, tosylate (p-toluenesulfonyl group), mesylate, or triflate (trifluoromethanesulfonate).

[1.1. Partially fluorinated ester]
By "partially fluorinated ester" refers a carboxylic acid having R _1, the carboxylic acid ester consisting of an alcohol having a leaving group X _1.
The alkyl group, the partially fluorinated alkyl group and the perfluoroalkyl group constituting R ₁ may each contain a branched or cyclic structure or an ether bond.
Examples of the aryl group constituting R ₁ include benzene, naphthalene, biphenyl and the like.

In the formula (2), at least one of R ₁ and R ₂ consists of a partially fluorinated alkyl group in which at least one of hydrogen bonded to the carbon of the base portion is substituted with a fluorine atom, or a perfluoroalkyl group. . When such conditions are satisfied, it is possible to suppress nucleophilic substitution of R ₁ during the reaction with the R ₂ anion.
The “carbon at the base” is the carbon constituting the carbonyl group (—C (═O) —) in the formula (1) or the carbon constituting the carbonyl group in the formula (2) (═C (— O-) Carbon directly bonded to ₂ ).
R ₁ is particularly preferably a perfluoroalkyl group. When R ₁ is a perfluoroalkyl group, nucleophilic substitution of R ₁ during the reaction with the R ₂ anion is further suppressed.

n is related to the number of carbon atoms between —O— and the leaving group X ₁ . In order to obtain a partially fluorinated dioxolane, n needs to be 1 or more.
On the other hand, if n becomes too large, formation of a ring structure becomes difficult. Therefore, n needs to be 5 or less. n is preferably 2 or less.

R represents a substituent bonded to carbon constituting the alcohol moiety. Each R consists of hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aryl group. Each R may be the same or different from each other.
The alkyl group constituting R may contain a branched or cyclic structure, or an ether bond.
Examples of the aryl group constituting R include benzene, naphthalene, biphenyl and the like.

The partially fluorinated ester is preferably synthesized from a compound represented by the formula (3) and provided with a structure represented by the formula (1.1). When a compound represented by the formula (3) is reacted with an alcohol having a leaving group X ₁ , a partially fluorinated ester represented by the formula (1.1) is obtained.

但し、
Ｒ₁は、（ｉ）炭素数１以上１０以下のアルキル基、部分フッ素化アルキル基若しくはパーフルオロアルキル基、又は、（ｉｉ）アリール基、
Ｘ₁は、Ｃｌ、Ｂｒ、Ｉ、トシラート、メシラート、又は、トリフラート。

However,
R ₁ is (i) an alkyl group having 1 to 10 carbon atoms, a partially fluorinated alkyl group or a perfluoroalkyl group, or (ii) an aryl group,
X ₁ is Cl, Br, I, tosylate, mesylate or triflate.

The partially fluorinated ester is particularly preferably one synthesized from trifluoroacetic acid (TFA) represented by the formula (3.1) and having a structure represented by the formula (1.2). When TFA represented by the formula (3.1) is reacted with an alcohol having a leaving group X ₁ , a partially fluorinated ester represented by the formula (1.2) is obtained. Further, when this partially fluorinated ester is reacted with CF ₃ anion, BTD is obtained.

但し、
Ｘ₁は、Ｃｌ、Ｂｒ、Ｉ、トシラート、メシラート、又は、トリフラート。

However,
X ₁ is Cl, Br, I, tosylate, mesylate or triflate.

  The compound represented by the formula (3) (particularly TFA) is less expensive than HFA. Therefore, when this is used as a starting material, partially fluorinated dioxolane can be produced at low cost. In addition, when this partially fluorinated dioxolane is used as a starting material, dioxole and an electrolyte can be produced at low cost.

[1.2. R ₂ anion]
“R ₂ anion” refers to a monovalent negatively charged structure (R ₂ ⁻ ) obtained by reacting compound R ₂ X ₂ with a reactant.
R ₂ represents (i) an alkyl group having 1 to 10 carbon atoms, a partially fluorinated alkyl group or a perfluoroalkyl group, or (ii) an aryl group.
The details of the alkyl group, the partially fluorinated alkyl group, the perfluoroalkyl group, and the aryl group constituting R ₂ are the same as those of R ₁ described above.
X ₂ is a leaving group and represents a silicon substituent such as H, Cl, Br, I, tosylate, mesylate, triflate, or trimethylsilyl group.

Examples of the compound capable of generating R ₂ anion (R ₂ X ₂ ) include:
(1) RfSiMe ₃ (TMSRf), RfH, RfI (where Rf is a perfluoroalkyl group such as CF ₃ ),
(2) Hexafluoroacetone DBU complex,
(3) PhSO ₂ CF ₃ ,
(4) TMSCF ₂ H, TMSCFH ₂ ,
and so on.

As a reactive agent, for example,
(1) alkali metals (Li, Na, K),
(2) alkaline earth metal (Mg),
(3) Alkali metal salts (CsF, LiHMDS, NaHMDS, KHMDS, tBuOK, KF),
(4) Tetraalkylammonium fluoride (NR ' ₄ F)
and so on.

When R ₂ X ₂ is reacted with the reactant, X ₂ is eliminated, and an ion pair structure of R ₂ ⁻ and M ⁺ (cation derived from the reactant) is obtained. The structure of R ₂ does not change when reacted with a reactant. Specific examples of the method for generating the R ₂ anion include the following methods.
(1) TMSRf and the CsF was reacted, Rf ^- method of generating.
(2) RfH and hexamethyldisilazane potassium (KHMDS) is reacted, Rf ^- method of generating.
Among RfH, CF ₃ H is a by-product compound in the synthesis of tetrafluoroethylene (TFE), but is usually a discarded reagent. However, enormous energy is required for the disposal. Since CF ₃ H can be used effectively in this method, the manufacturing cost can be reduced as compared with the case of using TMSCF ₃ . Also, the method using CF ₃ H is very valuable in other manufacturing processes in which CF ₃ groups are introduced nucleophilically.

(3) RfI and tetrakis - (dimethylamino) is reacted with ethylene (TDAE), Rf ^- method of generating.
(4) A method in which hexafluoroacetone DBU complex and tBuOK are reacted to generate CF ₃ ⁻ .
(5) A method of generating CF ₃ ⁻ by reacting PhSO ₂ CF ₃ and tBuOK.

[1.3. Partially fluorinated dioxolane]
When a partially fluorinated ester represented by the formula (1) is reacted with an R ₂ anion, a partially fluorinated dioxolane represented by the formula (2) is obtained. Since the details of the expression (2) are as described above, the description thereof is omitted.

[1.4. Reaction conditions]
When the partially fluorinated ester represented by the formula (1), the compound capable of generating R ₂ anion, and the reactant are dissolved in a solvent and reacted for a predetermined time, the partial fluorination represented by the formula (2) Dioxolane is obtained.
The solvent is preferably a non-aqueous polar solvent such as tetrahydrofuran (THF) or diethyl ether (Et ₂ O). This is because when the solvent contains water, the R ₂ anion is deactivated.
As the reaction temperature, an optimum temperature is selected according to the kind of the starting material. The reaction temperature may be a low temperature of 0 ° C. or lower, or may be room temperature.

[2. Method for producing dioxole]
The method for producing dioxole according to the present invention includes a step for producing dioxolol using the partially fluorinated dioxolane obtained by the method according to the present invention.
The method for producing dioxole from partially fluorinated dioxolane is not particularly limited, and a known method can be used.

For example, perfluoro-2,2-dimethyldioxole (PDD) is
(1) reacting bistrifluoromethyldioxolane (BTD) with Cl ₂ to produce intermediate (1) in which four substituents R are Cl;
(2) The intermediate (1) is reacted with SbCl ₅ and SbF ₃ to produce an intermediate (2) in which two Cls are substituted with F.
(3) The intermediate (2) can be produced by reducing with Mg or with TiCl ₄ and LiAlH ₄ . See equation (5) below.
Dioxoles other than PDD can be produced by the same method.

[3. Method for producing electrolyte]
The method for producing an electrolyte according to the present invention includes a step of producing an electrolyte using dioxole obtained by the method according to the present invention.
Since dioxole is a vinyl ether, a polymer can be synthesized by copolymerizing with a monomer having a vinyl group.
Examples of vinyl monomers copolymerized with dioxole include, for example:
(1) a vinyl ether monomer having a SO ₂ F group,
(2) tetrafluoroethylene (TFE),
(3) a vinyl ether monomer having -P (= O) (OR) ₂ group,
(4) vinyl monomer having a -SO ₂ NHSO ₂ Rf group,
and so on.

The following formula (4) shows an example of the reaction between dioxole and a vinyl ether monomer having a SO ₂ F group.

[4. Action]
Formula (5) shows a conventional PDD synthesis scheme. Conventionally, in order to synthesize PDD, first, a method of synthesizing BTD from HFA has been taken (see Patent Document 1). However, since HFA is expensive, the cost of PDD is increased, and as a result, the cost of the electrolyte polymer is increased.

HFA (anhydride) is a gas. In general, stability and handleability can be improved by using a hydrate (HFA.3H ₂ O) structure. Also, hydrates are less expensive than anhydrides.
However, if water is present when BTD is synthesized by the method of Patent Document 1, the target reaction does not proceed. The hydrogen atom of hexafluoroacetone hydrate has high acidity. Under acidic conditions, ethylene oxide and water react to produce ethylene glycol. From the above, it is difficult to obtain BTD by the reaction of hexafluoroacetone trihydrate and ethylene oxide. Therefore, when using a hydrate as a raw material, it is necessary to dehydrate beforehand.

  Further, the fact that the raw material is a gas means that a dedicated facility (pressure vessel) may be required for BTD synthesis, which also causes an increase in the cost of the PDD. On the other hand, in Patent Document 2, BTD is obtained by reacting HFA with 2-chlorohydrin and then dehydrohalogenating under basic conditions. Although this method does not require high temperature and high pressure, since the raw materials used are almost the same as in Patent Document 1, the production cost is expected to be high.

On the other hand, the partially fluorinated ester represented by the formula (1) is less expensive than HFA. For example, since the price of TFA is about 1/30 that of HFA, partially fluorinated esters synthesized using TFA are also low in cost. In addition, the partially fluorinated ester represented by the formula (1) can be synthesized using a reagent substantially free of water (for example, TFA that is liquid at normal temperature) as a starting material.
Therefore, when such a partially fluorinated ester is used as a starting material, a partially fluorinated dioxolane such as BTD can be produced at a low cost. When the partially fluorinated dioxolane thus obtained is used as a starting material, dioxole and an electrolyte polymer using the dioxole can be produced at low cost.

Example 1
A synthesis scheme of BTD is shown in the following formula (10.1).

Ester A (2-chloroethyl trifluoroacetate) (15.15 g) and CsF (15.42 g, 1.2 eq) were mixed, dehydrated THF (30 mL) was added, and the mixture was cooled to -78 ° C. To this, TMSCF ₃ (14 mL, 1.1 equivalent) was added and stirred for about 10 minutes. Thereafter, the temperature was gradually raised to room temperature, followed by stirring for 3 hours. From the ¹ H NMR spectrum of the crude solution, it was confirmed that the conversion rate of ester A was 100%.
This solution was distilled to obtain BTD (43% yield). Boiling point: 106 ° C. ¹ H NMR spectrum (CDCl ₃ ) 4.3 ppm (s), ¹⁹ F NMR spectrum (CDCl ₃ ) -80.1 ppm.

(Example 2)
The synthesis scheme of BTD is shown in the following formula (10.2).

Ester A (1.30 g) and CsF (1.23 g, 1.2 eq) were mixed, dehydrated THF (5 mL) was added, and the mixture was cooled to 0 ° C. To this, TMSCF ₃ (1.2 mL, 1.1 equivalent) was added and stirred for about 10 minutes. Thereafter, the temperature was raised to room temperature, followed by stirring for 3 hours. From the ¹ H NMR spectrum of the crude solution, it was confirmed that the conversion rate of ester A was 100%.

(Reference Example 3)
The following (10.3) formula shows a synthesis scheme of partially fluorinated dioxolane.

Dehydrated THF (5 mL) was added to ester A (1.51 g) and cooled to -78 ° C. To this, 3.6 mL (1.2 equivalents) of n-BuLi (2.6 M, hexane solution) was added and stirred for about 10 minutes. Thereafter, the temperature was gradually raised to room temperature, followed by stirring for 3 hours. From the ¹ H NMR spectrum of the crude solution, it was confirmed that the conversion rate of ester A was 100%.
The reaction was stopped by adding water, the organic layer was taken out and dried over MgSO ₄ . The presence of the cyclized product was confirmed by GC / MS (the area value ratio of the GC / MS spectrum was 11.3%).

Example 4
The following (10.4) Formula shows the synthetic scheme of partially fluorinated dioxolane.

2 Chloroethyl acetate (1.65 g) and CsF (2.45 g, 1.2 eq) were mixed, dehydrated THF (5 mL) was added, and the mixture was cooled to -78 ° C. To this, TMSCF ₃ (2.2 mL, 1.1 equivalents) was added and stirred for about 10 minutes. Thereafter, the temperature was raised to room temperature, followed by stirring for 3 hours. From the ¹ H NMR spectrum of the crude solution, it was confirmed that the ester conversion was 100%.
The reaction was stopped by adding water, and then the organic layer was taken out and dried over MgSO ₄ . The presence of a cyclized product was confirmed by GC / MS (17.5% in the area value ratio of GC / MS spectrum).

(Comparative Example 1)
The following (10.5) formula shows a synthesis scheme of partially fluorinated dioxolane.

Dehydrated THF (5 mL) was added to 2 chloroethyl acetate (1.48 g) and cooled to -78 ° C. To this, 5.1 mL (1.2 equivalents) of n-BuLi (2.6 M, hexane solution) was added and stirred for about 10 minutes. Thereafter, the temperature was gradually raised to room temperature, followed by stirring for 3 hours. From the ¹ H NMR spectrum of the crude solution, it was confirmed that the ester conversion was 100%.
The reaction was stopped by adding water, and then the organic layer was taken out and dried over MgSO ₄ . The solution part was taken out and the target product was inspected by GC / MS, but the compound considered to be a cyclized product was not contained.

(Example 5)
The following formula (10.6) shows a reaction formula of partially fluorinated dioxolane using the method according to the present invention.

  This reaction is considered to be a reaction mechanism that gives cyclized product B after passing through hemiketal (C) as an intermediate. It is known that when a nucleophilic agent composed of a hydrocarbon is allowed to act on a hydrocarbon-substituted ester, it decomposes into a ketone substituted with the nucleophilic agent and an alcohol (D).

Therefore, from the reaction of R ₁ (R ₁ = CX ₃ , X is F or H) and the nucleophile R ₂ Li (R ₂ = CX ₃ , X is F or H) by theoretical calculation, The formation enthalpies of the generated hemiketal structure C and D (ketone + lithium 2-chloroethoxide) were compared (Gaussian09). If C is more stable than D, it is considered that a reaction giving cyclized product B from C is likely to occur. Table 1 summarizes the enthalpy differences (kcal / mol) between C and D.

When both R ₁ and R ₂ are CH ₃ groups, the structure cannot be optimized with the hemiketal structure C, and the structure of D is given. In all other structures, the hemiketal structure C was thermodynamically more stable. Therefore, if at least one of R ₁ and R ₂ is substituted with F (in other words, if at least one hydrogen bonded to the carbon of the base portion is substituted with a fluorine atom), the ring It was found to give Compound B.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various modifications can be made without departing from the scope of the present invention.

  A method for producing a partially fluorinated dioxolane according to the present invention includes a light transmission material, a dustproof cover for a photomask, a protective coating material, an oxide film forming material on the negative electrode surface of a secondary battery, a gas separation membrane, and a high oxygen permeable electrolyte. It can be used as a method for producing raw materials.

Claims (6)

(1) and a partially fluorinated ester having a leaving group X ₁ having the structure represented by the formula, CF ₃ ^- is reacted with a partially fluorinated dioxolane having the structure represented by the formula (2) A process for producing a partially fluorinated dioxolane comprising a reaction step to obtain.

However,
R ₁ is a perfluoroalkyl group having 1 to 10 carbon atoms,
n is an integer of 1 to 5,
Each R is hydrogen, an alkyl group having 1 to 10 carbon atoms, or an aryl group,
X ₁ is Cl, Br, I, tosylate, mesylate or triflate. The partially fluorinated dioxolane according to claim 1, wherein the partially fluorinated ester is synthesized from a compound represented by the formula (3) and has a structure represented by the formula (1.1). Manufacturing method.

However,
R ₁ is a perfluoroalkyl group having 1 to 10 carbon atoms,
X ₁ is Cl, Br, I, tosylate, mesylate or triflate. The partially fluorinated ester is synthesized from trifluoroacetic acid (TFA) represented by the formula (3.1) and has a structure represented by the formula (1.2). Or the method for producing a partially fluorinated dioxolane described in 2;

However,
X ₁ is Cl, Br, I, tosylate, mesylate or triflate. The method for producing a partially fluorinated dioxolane according to claim 3, wherein the partially fluorinated dioxolane is bistrifluoromethyldioxolane. A method for producing dioxole comprising a step of obtaining a partially fluorinated dioxolane by the method according to any one of claims 1 to 4 and producing dioxole using the partially fluorinated dioxolane. A method for producing an electrolyte, comprising the step of obtaining dioxole by the method according to claim 5 and producing an electrolyte using the dioxole.