JP7839417B2 - Method for producing fluorine-containing dioxolane and composition useful for its production - Google Patents

Description

This disclosure relates to a method for producing fluorine-containing dioxolane and compositions useful for its production.

1,3-dioxolane compounds having a 2-(difluoromethylene) structure, such as perfluoro(2-methylene-4-methyl-1,3-dioxolane), are used as raw material monomers for fluororesins that constitute optical fibers. As a method for producing this perfluorodioxolane, for example, a method is known in which perfluoro(-3,6-bismethyl-1,4-dioxan-2-one) is used as a raw material and converted to a 2-COF compound, a 2-carboxylate salt, and a 2-methylene compound, as shown in the following formula (for example, Patent Document 1, Patent Document 2).

In this method, a carbonyl fluoride is generally reacted with a base to saponify it and convert it to a carboxylate salt, and then this carboxylate salt is thermally decomposed by heating to produce the desired difluoromethylene compound. However, if water, which is a proton source, is present when the carboxylate salt obtained from the carbonyl fluoride is thermally decomposed, not only the desired difluoromethylene compound but also an HF adduct (for example, 2-hydro-perfluoro(2,4-dimethyl-1,3-dioxolane) shown below) is formed by the addition of HF to the double bond in the difluoromethylene compound.
Because it also produces other substances, the yield of the target product decreases.

Furthermore, because the boiling point of this HF adduct is close to that of the target difluoromethylene compound, separating the HF adduct from the target difluoromethylene compound by distillation is not easy.

For this reason, attention is being paid to reducing the amount of water coexisting with carboxylates. For example, Patent Document 3 describes the following:
"The present inventors have diligently studied methods for producing perfluoro(2-methylene-4-methyl-1,3-dioxolane) and have found that at least one of the raw materials, perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) and its hydrolysis products, is reacted with a basic aqueous solution containing one or more cations selected from the group consisting of alkali metal ions and alkaline earth metal ions, and the resulting perfluoro(2,4-dimethyl-1,3-dioxolane-2-yl)carboxylic acid alkali metal We have newly discovered that by separating a liquid containing a salt or an alkaline earth metal salt of perfluoro(2,4-dimethyl-1,3-dioxolan-2-yl)carboxylate by liquid-liquid extraction, performing one or more water content reduction treatments selected from the group consisting of water distillation and water adsorption, and then using it for a decarboxylation reaction in the liquid phase, perfluoro(2-methylene-4-methyl-1,3-dioxolane) can be obtained in high yield while suppressing the formation of 2-hydro-perfluoro(2,4-dimethyl-1,3-dioxolane), which is difficult to separate.

International Publication No. 2020/166632 International Publication No. 2020/230822 International Publication No. 2020/095915

One objective of this disclosure is to provide a novel method for producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure (e.g., 2-(difluoromethylene)-4,4,5-trifluoro-5-(trifluoromethyl)-1,3-dioxolane) from a corresponding carboxylate salt, in which the by-production of an HF adduct (e.g., 2-hydro-perfluoro(2,4-dimethyl-1,3-dioxolane)) is suppressed.
One objective of this disclosure is to provide a composition containing the carboxylate salt that is useful for producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure in which the formation of HF adducts as by-products is suppressed.

The inventors have discovered that in the production process of 1,3-dioxolane compounds having a 2-(difluoromethylene) structure, if the pH of the product obtained by saponifying the carbonyl fluoride with a base to convert it to a carboxylate salt (or an aqueous solution of the product if the product is not an aqueous solution) is within the range of 7.0 to 11.0, or if the pH of the product (or an aqueous solution of the product if the product is not an aqueous solution) is outside the range of 7.0 to 11.0, the subsequent thermal decomposition of the carboxylate salt suppresses the formation of HF adducts as a by-product, thereby obtaining the target product of high purity.

This disclosure encompasses the following aspects:
Item 1.
Formula (1):
[In the formula, ^R1 to ^R4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen atom.]
A method for producing a compound represented by,
A manufacturing method comprising the following steps A, B, C, and D.
(Process A)
Formula (2):
[In the formula, X is a hydroxyl group, a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms are substituted with fluorine atoms, and ^R1 to ^R4 are the same as described above.]
The compound represented by
By reacting alkali metals and alkaline earth metals with at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides,
Formula (3):
[In the formula, M is an alkali metal atom or an alkaline earth metal atom, and ^R1 to ^R4 are the same as described above.]
Step A involves converting the compound to the compound represented by [formula] to obtain the reaction product.
(Process B)
Step B involves measuring the pH of the reaction product obtained in step A. If the pH is within the range of 7.0 to 11.0, the reaction product or a solution obtained by mixing the reaction product with water is used in the next step. If the pH is outside the range of 7.0 to 11.0, a pH-adjusted solution obtained by adjusting the pH of the reaction product to 7.0 to 11.0 is used in the next step.
(Process C)
Step C involves concentrating the reaction product obtained in Step A, the reaction product mixed with water, or the pH-adjusting solution, according to the pH measurement results in Step B, to obtain a concentrate.
(Process D)
Step D involves heating the concentrate obtained in step C to thermally decompose the compound represented by formula (3) and produce the compound represented by formula (1).
Item 2.
The manufacturing method according to claim 1, wherein each of the ^R1 to ^R4 is independently a fluorine atom, a perfluoroC1-C7 alkyl group, or a perfluoroC1-C7 alkoxy group.
Item 3.
The manufacturing method according to claim 1, wherein ^R1 is a trifluoromethyl group or a fluorine atom, and ^R2 to ^R4 are all fluorine atoms.
Item 4.
The manufacturing method according to any one of claims 1 to 3, wherein X is a hydroxyl group, a fluorine atom, a chlorine atom, methoxy, ethoxy, n-propoxy, i-propoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy.
Item 5.
The method for producing a product according to any one of claims 1 to 4, wherein the base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, sodium hydroxide, magnesium hydroxide, potassium methoxide, sodium methoxide, magnesium methoxide, potassium ethoxide, sodium ethoxide, and magnesium ethoxide.
Item 6.
The manufacturing method according to any one of claims 1 to 5, wherein the pH range of 7.0 to 11.0 in step B is 7.0 to 10.5.
Section 7.
The manufacturing method according to any one of claims 1 to 5, wherein step B is a step of measuring the pH of the reaction product obtained in step A, adjusting the pH of the reaction product to 7.0 to 9.0, and using the resulting pH-adjusted solution in the next step.
Section 8.
The manufacturing method according to any one of claims 1 to 7, wherein steps C and D are carried out continuously in the same reactor.
Item 9.
Formula (3):
[In the formula, ^R1 to ^R4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom.]
Compounds represented by formula (4):
[In the formula, Y is a hydrogen atom, or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms, and ^R1 to ^R4 are the same as described above.]
A composition comprising at least one compound selected from the group consisting of compounds represented by , and at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals,
A composition in which, if the composition is an aqueous solution of at least one compound selected from the group consisting of compounds represented by formula (3) and compounds represented by formula (4), its pH is in the range of 7.0 to 11.0, and if it is not an aqueous solution, the pH of the aqueous solution obtained by adding water to the composition is in the range of 7.0 to 11.0.
Item 10.
The composition according to claim 9, wherein each of the ^R1 to ^R4 is independently a fluorine atom, a perfluoroC1-C7 alkyl group, or a perfluoroC1-C7 alkoxy group.
Item 11.
The composition according to claim 9, wherein ^R1 is a trifluoromethyl group or a fluorine atom, and ^R2 to ^R4 are all fluorine atoms.
Item 12.
The composition according to any one of claims 9 to 11, wherein Y is a hydrogen atom, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl.
Item 13.
The composition according to any one of claims 9 to 12, wherein the base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, sodium hydroxide, magnesium hydroxide, potassium methoxide, sodium methoxide, magnesium methoxide, potassium ethoxide, sodium ethoxide, and magnesium ethoxide.
Section 14.
The composition according to any one of claims 9 to 13, wherein the pH of the aqueous solution is in the range of 7.0 to 10.5.
Item 15.
The composition according to any one of claims 9 to 13, wherein the pH of the aqueous solution is in the range of 7.0 to 9.0.
Section 16.
The composition according to any one of claims 9 to 15, wherein the composition is a non-aqueous solution of at least one compound selected from the group consisting of compounds represented by formula (3) and formula (4), and the water content is 3000 ppm or less relative to the mass of the composition.
Section 17.
The composition according to claim 16, wherein the water content is 1000 ppm or less relative to the mass of the composition.
Section 18.
The composition according to claim 16, wherein the water content is 100 ppm or less relative to the mass of the composition. Claim 19.
Formula (3):
[In the formula, ^R1 to ^R4 are each independently a C1-C7 fluoroalkyl group which may contain a fluorine atom or etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom.]
Compounds represented by formula (4):
[In the formula, Y is a hydrogen atom or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms, and ^R1 to ^R4 are the same as described above.]
A composition containing at least one compound selected from the group consisting of compounds represented by , and water,
A composition having a water content of 1 ppm to 400 ppm relative to the mass of the composition.
Section 20.
The composition according to claim 19, wherein the water content is 1 ppm to 200 ppm relative to the mass of the composition.
Section 21.
The composition according to claim 19, wherein the water content is 1 ppm to 100 ppm relative to the mass of the composition.
Section 22.
The composition according to any one of claims 19 to 21, wherein each of the ^R1 to ^R4 is independently a fluorine atom, a perfluoroC1-C7 alkyl group, or a perfluoroC1-C7 alkoxy group.
Section 23.
The composition according to any one of claims 19 to 21, wherein ^R1 is a trifluoromethyl group or a fluorine atom, and ^R2 to ^R4 are all fluorine atoms.
Section 24.
The composition according to any one of claims 19 to 23, wherein Y is a hydrogen atom, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl.

According to this disclosure, when producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure by thermal decomposition of the corresponding carboxylate salt, the generation of the by-product 2-hydro-2-trifluoromethyl compound can be reduced, and the target product of high purity can be produced.
When the compositions of this disclosure are used as raw materials for the production of 1,3-dioxolane compounds having a 2-(difluoromethylene) structure, the generation of by-products can be suppressed, and 1,3-dioxolane compounds having a 2-(difluoromethylene) structure can be obtained in high purity.

The foregoing summary of this disclosure is not intended to describe any of the disclosed embodiments or all implementations of this disclosure.
The following description in this disclosure provides more specific examples of the embodiments.
In several places in this disclosure guidance is provided through examples, and these examples can be used in various combinations.
In each case, the exemplary group can function as a non-exclusive and representative group.
All publications, patents, and patent applications cited herein are incorporated herein by direct reference.

Unless otherwise specified, the terms, symbols, and abbreviations used herein should be understood to have the meanings commonly used in the technical field to which this disclosure pertains, in the context of this specification.

In this specification, the phrase "contains" is used to include the phrases "essentially derived from" and "consist of."

Unless otherwise specified, the processes, treatments, or operations described herein may be carried out at room temperature.
In this specification, room temperature can mean a temperature within the range of 10 to 40°C.

In this specification, the notation "Cn-Cm" (where n and m are numbers) represents a carbon atom with n or more carbon atoms and m or less carbon atoms, as would be commonly understood by those skilled in the art.

Unless otherwise specified herein, "alkyl group" refers to linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4), particularly preferably C1-C3 alkyl groups such as methyl, ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl), pentyl (e.g., n-pentyl, tert-pentyl, neopentyl, isopentyl, sec-pentyl, 3-pentyl), hexyl, heptyl, octyl, nonyl, and decyl; and cyclic C3-C10 (e.g., C3-C6, C4-C6, C3-C5, C5-C6) alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and adamantyl.

In this specification, unless otherwise specified, "alkoxy group" may be a group represented by RO-[wherein R is an alkyl group (e.g., C1-C10 alkyl group)].
Examples of alkoxy groups include linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4), particularly preferably C1-C3 alkyl groups such as methyl, ethyl, propyl (e.g., n-propyl, isopropyl), butyl (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl), pentyl (e.g., n-pentyl, tert-pentyl, neopentyl, isopentyl, sec-pentyl, 3-pentyl), hexyl, heptyl, octyl, nonyl, and decyl, as well as cyclic C3-C10 (e.g., C3-C6, C4-C6, C3-C5, C5-C6) alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, and adamantyl.

In this specification, unless otherwise specified, "fluoroalkyl group" refers to an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and also includes perfluoroalkyl groups in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms.
The number of carbon atoms in the fluoroalkyl group can be, for example, 1 to 10, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1.
Examples of fluoroalkyl groups include linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4, particularly preferably C1-C3) fluoroalkyl groups (preferably perfluoroalkyl groups), such as methyl having 1-3 fluorine atoms, ethyl having 1-5 fluorine atoms, propyl having 1-7 fluorine atoms (e.g., n-propyl, isopropyl), butyl having 1-9 fluorine atoms (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl), pentyl having 1-11 fluorine atoms (e.g., n-pentyl, tert-pentyl, neopentyl, isopentyl, sec-pentyl, 3-pentyl), hexyl having 1-13 fluorine atoms, heptyl having 1-15 fluorine atoms, octyl having 1-17 fluorine atoms, nonyl having 1-19 fluorine atoms, and decyl having 1-21 fluorine atoms.
The number of fluorine atoms in a fluoroalkyl group can range from one to the maximum number of substituted atoms, for example, 1 to 21, 1 to 19, 1 to 17, 1 to 15, 1 to 13, 1 to 11, 1 to 9, 1 to 7, 1 to 5, 1 to 3, etc.

In this specification, unless otherwise specified, "fluoroalkoxy group" refers to an alkoxy group in which at least one hydrogen atom is substituted with a fluorine atom, and also includes perfluoroalkoxy groups in which all hydrogen atoms of the alkoxy group are substituted with fluorine atoms.
The number of carbon atoms in the fluoroalkoxy group can be, for example, 1 to 10, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1.
Examples of fluoroalkoxy groups include methoxy having 1 to 3 fluorine atoms, ethoxy having 1 to 5 fluorine atoms, propoxy having 1 to 7 fluorine atoms (e.g., n-propoxy, isopropoxy), butoxy having 1 to 9 fluorine atoms (e.g., n-butoxy, isobutoxy, sec-butoxy, tert-butoxy), and pentoxy having 1 to 11 fluorine atoms (e.g., n-pentoxy, tert-pentoxy, neopentoxy, isopentoxy, sec-pentoxy, 3-pentoxy). The fluoroalkoxy groups (preferably perfluoroalkoxy groups) are linear or branched, C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4, particularly preferably C1-C3), such as hexyloxy having 1 to 13 fluorine atoms, heptyloxy having 1 to 15 fluorine atoms, octyloxy having 1 to 17 fluorine atoms, nonyloxy having 1 to 19 fluorine atoms, and decyloxy having 1 to 21 fluorine atoms.
The number of fluorine atoms in the fluoroalkoxy group can range from one to the maximum number that can be substituted, for example, 1 to 21, 1 to 19, 1 to 17, 1 to 15, 1 to 13, 1 to 11, 1 to 9, 1 to 7, 1 to 5, 1 to 3, etc.

In this specification, unless otherwise specified, "C1-C7 fluoroalkyl group which may contain etheric oxygen" includes the aforementioned fluoroalkyl groups having 1 to 7 carbon atoms, and C1-C7 fluoroalkyl groups containing etheric oxygen. Furthermore, "C1-C7 fluoroalkyl group which may contain etheric oxygen" includes perfluoro C1-C7 alkyl groups which may contain etheric oxygen, in which all hydrogen atoms of the alkyl group are replaced with fluorine atoms.
C1-C7 fluoroalkyl groups containing etheric oxygen include C1-C7 fluoroalkyl groups (preferably perfluoroC1-C alkyl groups) that have an etheric oxygen atom, "-O-", at their terminus or internally. Therefore, C1-C7 fluoroalkyl groups containing etheric oxygen can also be referred to as groups having an etheric oxygen atom at the terminus or between carbon-carbon bonds of a C1-C7 fluoroalkyl group. Trifluoromethoxy ( _CF3 -O-) is an example of a fluoroalkyl group having "-O-" at its terminus, and perfluoro(methoxymethyl) ( _CF3 -O- _CF2- ) is an example of a fluoroalkyl group having "-O-" internally in its structure.
The number of etheric oxygen atoms in a C1-C7 fluoroalkyl group containing etheric oxygen can be 1, 2, 3, etc., but 1 or 2 is preferred, and 1 is preferred.
The number of carbon atoms in the C1-C7 fluoroalkyl group containing etheric oxygen is 1 to 7, preferably C1-C6, more preferably C1-C4, and even more preferably C1-C3.

C1-C7 fluoroalkyl groups containing etheric oxygen include C1-C7 fluoroalkoxy groups, C1-C6 fluoroalkoxytrifluoromethyl groups, C1-C5 fluoroalkoxypentafluoroethyl groups, and others.

Examples of C1-C7 fluoroalkoxy groups include methoxy groups having 1-3 fluorine atoms, ethoxy groups having 1-5 fluorine atoms, propoxy groups having 1-7 fluorine atoms (e.g., n-propoxy, isopropoxy), butoxy groups having 1-9 fluorine atoms (e.g., n-butoxy, isobutoxy, sec-butoxy, tert-butoxy), pentyloxy groups having 1-11 fluorine atoms (e.g., n-pentyloxy, tert-pentyloxy, neopentyloxy, isopentyloxy, sec-pentyloxy, 3-pentyloxy), hexyloxy groups having 1-13 fluorine atoms, and heptyloxy groups having 1-15 fluorine atoms.

The C1-C6 fluoroalkoxytrifluoromethyl group is C1-C6 fluoroalkoxy- _CF2- . Examples of C1-C6 fluoroalkoxy groups are described in the "Examples of Fluoroalkoxy Groups" above.

The C1-C5 fluoroalkoxypentafluoroethyl group is C1-C5 fluoroalkoxy- _CF2- . Examples of C1-C5 fluoroalkoxy groups are described in the examples of "fluoroalkoxy groups" above.

In this specification, unless otherwise specified, "a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms" includes C1-C3 alkyl groups and C1-C3 alkyl groups in which one or more hydrogen atoms are substituted with fluorine atoms. In other words, "a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms" includes C1-C3 alkyl groups and C1-C3 fluoroalkyl groups. Furthermore, a C1-C3 alkyl group in which one or more hydrogen atoms are substituted with fluorine atoms includes perfluoroC1-C3 alkyl groups in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms.
Examples of C1-C3 alkyl groups and C1-C3 fluoroalkyl groups are described in the above-mentioned examples of alkyl groups and fluoroalkyl groups.

In this specification, unless otherwise specified, "a C1-C3 alkoxy group in which one or more hydrogen atoms may be substituted with fluorine atoms" includes a C1-C3 alkoxy group and a C1-C3 alkoxy group in which one or more hydrogen atoms are substituted with fluorine atoms. In other words, "a C1-C3 alkoxy group in which one or more hydrogen atoms may be substituted with fluorine atoms" includes a C1-C3 alkoxy group and a C1-C3 fluoroalkoxy group. Furthermore, a C1-C3 alkoxy group in which one or more hydrogen atoms are substituted with fluorine atoms includes a perfluoroC1-C3 alkoxy group in which all hydrogen atoms of the alkoxy group are substituted with fluorine atoms.
Examples of C1-C3 alkoxy groups and C1-C3 fluoroalkoxy groups are described in the examples of alkoxy groups and fluoroalkoxy groups mentioned above.

In this specification, unless otherwise specified, examples of "alkali metals" include lithium, sodium, potassium, rubidium, cesium, and francium; preferred examples include lithium, sodium, and potassium; and more preferred examples include sodium and potassium.

In this specification, unless otherwise specified, examples of "alkaline earth metals" include beryllium, magnesium, calcium, strontium, barium, and radium, with preferred examples including magnesium and calcium.

Method for producing a compound represented by formula (1) One embodiment of the present disclosure is formula (1):
[In the formula, ^R1 to ^R4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen atom.]
This is a method for producing a compound represented by (which may be referred to as compound (1) in this specification).
The manufacturing method includes steps A, B, C, and D.
Steps A, C, and D, with the exception of step B, may be carried out in known ways, for example, in accordance with the methods described in Patent Document 1, Patent Document 2, Japanese Patent Application Publication No. 2005-002014, U.S. Patent No. 3,308,107, or U.S. Patent No. 6,664,431. These publications are incorporated herein by reference.

^R1 to ^R4 can each be independently a fluorine atom, a linear or branched C1-C7 fluoroalkyl group, or a linear or branched C1-C7 fluoroalkyl group containing etheric oxygen.
^R1 to ^R4 can each be independently a fluorine atom, a linear or branched C1-C6 fluoroalkyl group, or a linear or branched C1-C6 fluoroalkyl group containing etheric oxygen.
^R1 to ^R4 can each be independently a fluorine atom, a linear or branched C1-C5 fluoroalkyl group, or a linear or branched C1-C5 fluoroalkyl group containing etheric oxygen.
^R1 to ^R4 can each be independently a fluorine atom, a linear or branched C1-C4 fluoroalkyl group, or a linear or branched C1-C4 fluoroalkyl group containing etheric oxygen.
^R1 to ^R4 can each be independently a fluorine atom, a linear or branched C1-C3 fluoroalkyl group, or a linear or branched C1-C3 fluoroalkyl group containing etheric oxygen.

^R1 to ^R4 can each be independently a fluorine atom, a linear or branched perfluoroC1-C7 alkyl group, or a linear or branched perfluoroC1-C7 alkyl group containing etheric oxygen.
^R1 to ^R4 can each independently be a fluorine atom, a linear or branched perfluoroC1-C6 alkyl group, or a linear or branched perfluoroC1-C6 alkyl group containing etheric oxygen.
^R1 to ^R4 can each independently be a fluorine atom, a linear or branched perfluoroC1-C5 alkyl group, or a linear or branched perfluoroC1-C5 alkyl group containing etheric oxygen.
^R1 to ^R4 can each be independently a fluorine atom, a linear or branched perfluoroC1-C4 alkyl group, or a linear or branched perfluoroC1-C4 alkyl group containing etheric oxygen.
^R1 to ^R4 can each independently be a fluorine atom, a linear or branched perfluoroC1-C3 alkyl group, or a linear or branched perfluoroC1-C3 alkyl group containing etheric oxygen.

^R1 to ^R4 can each be independently a fluorine atom, a perfluoroC1-C7 alkyl group, or a perfluoroC1-C7 alkoxy group.
^R1 to ^R4 can each be independently a fluorine atom, a perfluoroC1-C6 alkyl group, or a perfluoroC1-C6 alkoxy group.
^R1 to ^R4 can each be independently a fluorine atom, a perfluoroC1-C5 alkyl group, or a perfluoroC1-C5 alkoxy group.
^R1 to ^R4 can each be independently a fluorine atom, a perfluoroC1-C4 alkyl group, or a perfluoroC1-C4 alkoxy group.
^R1 to ^R4 can each be independently a fluorine atom, a perfluoro C1-C3 alkyl group, or a perfluoro C1-C3 alkoxy group.

^R1 to ^R4 each have at least one fluorine atom, and the remaining groups, if there are multiple such remaining groups, may independently be perfluoroC1-C2 alkyl groups or perfluoroC1-C3 alkoxy groups.
^R1 to ^R4 consist of at least two fluorine atoms, and the remaining groups, if there are multiple such remaining groups, may independently be perfluoroC1-C2 alkyl groups or perfluoroC1-C3 alkoxy groups.
^R1 to ^R4 have at least three groups consisting of fluorine atoms, and the remaining group consists of perfluorocarbons.
It may be a 1-C3 alkyl group or a perfluoroC1-C2 alkoxy group.
^R1 to ^R4 may consist of at least three fluorine atoms, and the remaining groups may be perfluoro C1-C3 alkyl groups.
^R1 to ^R4 may all be fluorine atoms.
^R1 may be a trifluoromethyl group or a fluorine atom, and ^R2 to ^R4 may all be fluorine atoms.

Specific examples of compound (1) are perfluoro(2-methylene-1,3-dioxolane), perfluoro(2-methylene-4-methyl-1,3-dioxolane), perfluoro(2-methylene-4-ethyl-1,3-dioxolane), perfluoro(2-methylene-4,5-dimethyl-1,3-dioxolane), perfluoro(2-methylene-4,5-diethyl-1,3-dioxolane), perfluoro(2 It includes -methylene-4-methoxymethyl-1,3-dioxolane), perfluoro(2-methylene-4-ethoxymethyl-1,3-dioxolane), 2-(difluoromethylene)-3a,4,4,6,6,6a-hexafluorotetrahydrofluoro[3,4-d][1,3]dioxol, and 2-(difluoromethylene)-3a,4,4,5,5,6,6,7,7,7a-decafluorohexahydrobenzo[d][1,3]dioxol, and perfluoro(2-methylene-1,3-dioxolane),
Perfluoro(2-methylene-4-methyl-1,3-dioxolane) is preferred.

Process A
In process A, equation (2):
[In the formula, X is a hydroxyl group, a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms are substituted with fluorine atoms, and ^R1 to ^R4 are the same as described above.]
A compound represented by (which may be referred to as compound (2) in this specification) is reacted with at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals.
Formula (3):
[In the formula, M is an alkali metal atom or an alkaline earth metal atom, and ^R1 to ^R4 are the same as described above.]
The reaction product is obtained by converting to a compound represented by (which may be referred to as compound (3) in this specification).

Compound (2) is a known compound and can be produced, for example, by the method described in Patent Document 1 or 2, or by appropriately modifying said method.

X can be a hydroxyl group, a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms are substituted with fluorine atoms. X can be a hydroxyl group, a fluorine atom, a chlorine atom, methoxy, ethoxy, n-propoxy, i-propoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy. X can be a hydroxyl group, a fluorine atom, methoxy, ethoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy.
X can be a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms may be substituted with a fluorine atom. X can be a fluorine atom, a chlorine atom, methoxy, ethoxy, n-propoxy, i-propoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy. X can be a fluorine atom, methoxy, ethoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy. X can be a fluorine atom, methoxy, or trifluoromethoxy.

Specific examples of compound (2) are perfluoro(2-formyl-2,4-dimethyl-1,3-dioxolane), 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carbonyl chloride, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid methyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid ethyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid n-propyl ester, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid This includes i-propyl esters, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid trifluoromethyl esters, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid 2,2,2-trifluoroethyl esters.
Preferred specific examples of compound (2) include perfluoro(2-formyl-2,4-dimethyl-1,3-dioxolane), 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid methyl ester, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid trifluoromethyl ester.

The bases include alkali metal hydroxides, carbonates, and alkoxides, as well as alkaline earth metal hydroxides, carbonates, and alkoxides, and may be used individually or in combination of two or more.
Examples of hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, calcium hydroxide, and barium hydroxide.
Examples of carbonates include sodium carbonate, potassium carbonate, lithium carbonate, magnesium carbonate, calcium carbonate, barium carbonate, sodium bicarbonate, potassium bicarbonate, and lithium bicarbonate.
Examples of alkoxides include sodium methoxide, sodium ethoxide, sodium butoxide, potassium methoxide, potassium ethoxide, potassium butoxide, lithium methoxide, lithium ethoxide, magnesium methoxide, magnesium ethoxide, calcium methoxide, and calcium ethoxide.

The base is preferably at least one selected from the group consisting of potassium carbonate, sodium carbonate, magnesium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, sodium hydroxide, magnesium hydroxide, potassium methoxide, sodium methoxide, magnesium methoxide, potassium ethoxide, sodium ethoxide, and magnesium ethoxide.
The base is more preferably at least one selected from the group consisting of potassium carbonate, sodium carbonate, magnesium carbonate, potassium hydroxide, and sodium hydroxide.

Compound (3) is a carboxylate salt of compound (2) corresponding to the base used in step A. Specific examples and preferred examples of compound (3) are carboxylate salts corresponding to specific examples and preferred examples of compound (2), respectively.
M can be an alkali metal atom or an alkaline earth metal atom.
M is preferably an alkali metal atom, and more preferably a potassium atom or a sodium atom.
M can be a group corresponding to the base used in step A. Therefore, if the base is a potassium salt, M can be a potassium atom.

Step A may be carried out in the presence or absence of a solvent.
Water or an organic solvent may be used as the solvent. The solvent can be used alone or in combination of two or more.

Examples of organic solvents include alkyl alcohol solvents, ether solvents, aromatic solvents, saturated hydrocarbon solvents, nitrile solvents, sulfoxide solvents, and halogenated hydrocarbon solvents.
Suitable examples of organic solvents include alkyl alcohol solvents, ether solvents, halogenated hydrocarbon solvents, and nitrile solvents.

Examples of alkyl alcohol solvents include linear or branched C1-C10 alkyl alcohols, preferably linear or branched C1-5 alkyl alcohols, more preferably linear or branched C1-4 alkyl alcohols, even more preferably methanol, ethanol, n-propanol, isopropanol, n-butyl alcohol, sec-butyl alcohol, or tert-butyl alcohol, and particularly preferably methanol or ethanol.

Suitable examples of ether-based solvents include dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran, and 1,2-dimethoxyethane and crown ethers.

Suitable examples of aromatic solvents include benzene, toluene, and xylene.
Suitable examples of saturated hydrocarbon solvents include n-pentane, n-hexane, cyclohexane, and n-heptane.
Suitable examples of nitrile solvents include 1,4-dicyabutane, acetonitrile, and benzonitrile.
Suitable examples of sulfoxide solvents include dimethyl sulfoxide and sulfolane.
Suitable examples of halogenated hydrocarbon solvents include methylene chloride, chloroform, carbon tetrachloride, 1,2-dichloroethane, 1,2-dichlorobenzene, and chlorobenzene and perfluorohexane.

Suitable examples of organic solvents include methanol, ethanol, dimethyl ether (DME), diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,4-dicyabutane, methylene chloride, chloroform, tetrahydrofuran, perfluorohexane, and acetonitrile.

The amount of base used in step A may be preferably in the range of 0.05 to 10 moles, more preferably in the range of 0.1 to 10 moles, and even more preferably in the range of 0.1 to 5 moles, per mole of compound (2).
Furthermore, the amount of base may be such that the pH of the aqueous solution of the reaction product obtained in step A falls within a predetermined range (for example, 7.0 to 11.0, preferably 7.0 to 10.5, more preferably 7.0 to 9.0). If the amount is such that the step of adjusting the pH of the aqueous solution in the next step B can be omitted.

When using a solvent in process A, the amount should be determined based on common technical knowledge and other factors that allow it to function as a solvent.

The reaction temperature in step A is preferably in the range of -50 to 120°C, more preferably in the range of -20 to 100°C, and even more preferably in the range of -10 to 70°C.

The reaction time in step A is not particularly limited as long as the target substance is produced, but is preferably in the range of 0.1 hours to 48 hours, more preferably in the range of 0.1 hours to 24 hours, and even more preferably in the range of 0.1 hours to 12 hours.

In step A, compound (2) is converted to compound (3), and a reaction product containing compound (3) is obtained.
The reaction product may be an aqueous solution or a non-aqueous solution. An aqueous solution includes aqueous solutions of compound (3). A non-aqueous solution includes organic solvents containing compound (3) and solids containing compound (3).
If water or a mixed solvent of water and another solvent is used as the solvent in step A, the reaction product is obtained as an aqueous solution of compound (3).
When an organic solvent is used as the solvent in step A, the reaction product is obtained as an organic solvent containing compound (3).
If no solvent is used in step A, the reaction product is obtained as a solid containing compound (3).
The reaction product is subjected to the next step B.

Process B
Step B is a step in which the pH of the reaction product obtained in Step A (which may be a concentrated reaction product) is checked by pH measurement to ensure that it is between 7.0 and 11.0 (preferably 7.0 and 10.5, more preferably 7.0 and 9.0) before being subjected to the concentration step in the next step C. If the pH is outside this range, the pH is adjusted to bring it within that range. Therefore, if the pH of the reaction product obtained in Step A is between 7.0 and 11.0 (preferably 7.0 and 10.5, more preferably 7.0 and 9.0), it is not necessary to adjust the pH of the reaction product.
Therefore, in step B, the pH of the reaction product obtained in step A (i.e., the reaction product containing compound (3)) is measured and adjusted to 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0) as necessary.
pH may be a value determined by pH test strips, a pH meter (for example, HORIBA F-74 benchtop pH/water quality analyzer), or titration using a pH indicator.
The reaction product obtained in step A may be a liquid or a solid.
If the measured pH is within the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0), the reaction product obtained in step A is adjusted to the pH in step B.
The product may be subjected to step C after measurement, or the reaction product obtained in step A may be mixed with water to obtain a liquid (sometimes referred to as "water mixture") which may then be subjected to step C. If the reaction product is a solid and dissolves in water, the water mixture may be an aqueous solution of the solid.
If the measured pH is outside the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0), a solution (sometimes referred to as "pH-adjusted solution") in which the pH of the reaction product obtained in step A has been adjusted to the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0) can be supplied to step C.

Let's explain pH measurement.
If the reaction product obtained in step A is an aqueous solution of compound (3), then part or all of this aqueous solution can be subjected to pH measurement.
If the reaction product obtained in step A is an organic solvent containing compound (3), a mixture obtained by mixing some or all of this organic solvent with water can be used for pH measurement. If the mixture separates into an aqueous phase and an organic phase when allowed to stand, the aqueous phase can be used for pH measurement.
If the reaction product obtained in step A is a solid containing compound (3), water can be mixed with part or all of this solid to dissolve compound (3), and the resulting solution can be used for pH measurement.

For pH adjustment, known substances can be used as pH adjusters. Examples of substances used for pH adjustment include, as acids, aqueous solutions of hydrogen fluoride, sulfuric acid, hydrogen chloride, and phosphoric acid; and as bases, potassium carbonate, sodium carbonate, magnesium carbonate, potassium hydroxide, sodium hydroxide, sodium methoxide, sodium ethoxide, sodium butoxide, potassium methoxide, potassium ethoxide, potassium butoxide, magnesium methoxide, magnesium ethoxide, calcium methoxide, and calcium ethoxide. These can be used individually or in combination of two or more.

Process C
In step C, the reaction product obtained in step A, a solution obtained by mixing the reaction product with water (water mixture), or a pH adjusting solution is concentrated according to the pH measurement results in step B.

The concentration process can be carried out in accordance with known concentration methods. Examples of concentration methods include vacuum distillation, drying, extraction, precipitation, distillation, and chromatography, which can be used individually or in combination of two or more. Preferred concentration methods are vacuum distillation and drying.
Examples of concentration conditions include vacuum distillation at 0–140°C and drying at 0–140°C.
The concentrate obtained by concentration can be liquid, gel-like, or solid.
In the concentration step, the compound (3) is concentrated until its concentration reaches, for example, 99% by mass or more.

Process D
In step D, the concentrate obtained in step C is heated. By heating the concentrate, compound (3) contained in the concentrate is decarboxylated, and compound (1) is produced in high purity.

Step D may be carried out in an organic solvent or without a solvent. The organic solvent is not particularly limited as long as it can decarboxylate compound (3). The organic solvent may be any solvent known to be usable for the decarboxylation of compound (3). Examples and preferred examples of organic solvents are the same as those for the organic solvent in Step A. Preferred specific examples of organic solvents include 1,2-dimethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,4-dicyabutane, and acetonitrile.

The amount of organic solvent used in step D should be determined based on common technical knowledge and other factors, selecting an amount that functions effectively as a solvent.

The reaction temperature in step D may preferably be in the range of 50 to 400°C, more preferably 70 to 300°C, and even more preferably 100 to 200°C, if a solvent is present. If no solvent is present, the reaction temperature may preferably be in the range of 100 to 400°C, more preferably 150 to 400°C, and even more preferably 150 to 350°C.

The reaction time in step D is not particularly limited as long as compound (1) is formed, but is preferably in the range of 0.1 hours to 48 hours, more preferably in the range of 0.1 hours to 24 hours, and even more preferably in the range of 0.1 hours to 12 hours.

The reaction in step D may be carried out in or without an inert gas (e.g., nitrogen gas), preferably in its absence.

Process D may be carried out under reduced pressure, atmospheric pressure, or pressurized conditions.

The compound (1) produced in step D can be isolated or purified, if desired, by conventional methods such as extraction, dissolution, concentration, precipitation, dehydration, adsorption, distillation, rectification, chromatography, or a combination thereof.

Composition (1)
One embodiment of the present disclosure is formula (3):
[In the formula, ^R1 to ^R4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom.]
Compounds represented by formula (4):
[In the formula, Y is a hydrogen atom, or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms, and ^R1 to ^R4 are the same as described above.]
The composition contains at least one compound selected from the group consisting of compounds represented by (which may be referred to as compound (4) in this specification), and at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals.

The composition may be an aqueous solution or a non-aqueous solution. The aqueous solution includes an aqueous solution of at least one compound selected from the group consisting of compounds (3) and (4). The non-aqueous solution includes an organic solvent containing at least one compound selected from the group consisting of compounds (3) and (4), or a solid containing at least one compound selected from the group consisting of compounds (3) and (4).
The composition (which may be referred to as composition (1) in this specification) is such that, if it is an aqueous solution, its pH is in the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0), and if it is not an aqueous solution, the pH of the aqueous solution obtained by adding water to the composition is in the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0).

Y can be a hydrogen atom, or a C1-C3 alkyl group in which one or more hydrogen atoms are substituted with fluorine atoms.
Y can be a hydrogen atom, a C1-C3 alkyl group, or a perfluoro C1-C3 alkyl group.
Y can be a hydrogen atom, or a C1-C3 alkyl group in which one or more hydrogen atoms are substituted with fluorine atoms.
Y can be a hydrogen atom or a C1-C3 alkyl group.
Y can be a hydrogen atom or a perfluoro C1-C3 alkyl group.

Examples of Y include hydrogen atoms, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, perfluoron-propyl, and perfluoroi-propyl.
Y may be a hydrogen atom, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl.
Y may be a hydrogen atom, methyl, ethyl, or trifluoromethyl.
Y may be methyl, ethyl, n-propyl, or i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl.

For details regarding ^R1 to ^R4 and M in equations (3) and (4), the above-mentioned descriptions apply.

Specific examples of compound (4) are 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid methyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid ethyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid n-propyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid i-propyl ester, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid This includes trifluoromethyl esters, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid, and 2,2,2-trifluoroethyl ester.
Preferred specific examples of compound (4) include 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid methyl ester, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid trifluoromethyl ester.

Since compounds (3) and (4) are produced by step A, composition (1) is
The composition may be the reaction product obtained in step A, a water mixture of the reaction product (for example, an aqueous solution of the reaction product), a pH adjusting solution, etc. Therefore, this composition can be produced by steps A, B, etc. This composition can also be produced by mixing at least one compound selected from the group consisting of compound (3) and compound (4), and the base.

Composition (1) may be the reaction product obtained in step A, which may be the target of concentration in step C, a liquid obtained by mixing the reaction product with water, or a pH adjusting solution obtained by adjusting the pH of the reaction product to pH 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0).
Therefore, composition (1) can be the reaction product obtained in step A or a liquid obtained by mixing water with the reaction product obtained in step A, when the pH of the reaction product obtained in step A is in the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0), and when the pH of the aqueous solution of the reaction product obtained in step A is outside the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0), it can be a liquid obtained by adjusting the pH of the reaction product obtained in step A to within the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0).

Composition (1) may contain at least one compound selected from the group consisting of compound (3) and compound (4) in an amount of, for example, 1 to 99.9% by mass, preferably 10 to 99.9% by mass, and more preferably 50 to 99.9% by mass, relative to the mass of composition (1).

When composition (1) contains compound (3) and compound (4), the content of compound (3) can be, for example, 0.1 to 99.9% by mass, preferably 50 to 99.9% by mass, and more preferably 75 to 99.9% by mass, relative to the total content of compound (3) and compound (4).

Composition (1) may contain a base in an amount of, for example, 0.1 ppm to 500 ppm relative to the mass of composition (1), preferably 0.1 ppm to 100 ppm, and more preferably 0.1 ppm to 50 ppm.

If composition (1) is a non-aqueous solution, composition (1) may contain a small amount of water. Composition (1) may contain water in an amount of, for example, 3000 ppm or less relative to the mass of composition (1), preferably 1000 ppm or less, and more preferably 100 ppm or less.
If composition (1) is a non-aqueous solution and contains water, composition (1) may contain water in an amount of, for example, 1 ppm or more, preferably 5 ppm or more, and more preferably 10 ppm or more, relative to the mass of composition (1).
The amount of water contained in composition (1) can be within a range obtained by appropriately combining the upper and lower limits, for example, 1 ppm to 3000 ppm, 5 ppm to 3000 ppm, 10 ppm to 3000 ppm, 1 ppm to 1000 ppm, 5 ppm to 1000 ppm, 10 ppm to 1000 ppm, 1 ppm to 100 ppm, 5 ppm to 100 ppm, 10 ppm to 100 ppm, etc.

Composition (1) may contain, in addition to at least one compound selected from the group consisting of compound (3) and compound (4), and a base, other components. Examples of other components include alkali metal or alkaline earth metal salts of hydrogen halides, alkali metal or alkaline earth metal salts of inorganic acids, etc. Composition (1) may contain the other components in an amount of, for example, 0.1 to 30% by mass relative to the mass of composition (1).

By subjecting composition (1) to step C for concentration and heating the concentrate in step D, compound (3) is decarboxylated, producing high-purity compound (1). At the same time, the formation of HF adducts, which are by-products and difficult to separate from compound (1), is reduced. This is presumed to be due to the pH of composition (1) being in the range of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0). Composition (1) is useful as a source of compound (1).

Composition (2)
One embodiment of the present disclosure is formula (3):
[In the formula, ^R1 to ^R4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom.]
Compounds represented by formula (4):
[In the formula, Y is a hydrogen atom, or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms, and ^R1 to ^R4 are the same as described above.]
A composition containing at least one compound selected from the group consisting of compounds represented by [formula], and water, wherein the water content is 1 ppm to 400 ppm relative to the mass of the composition (this composition may be referred to as composition (2) in this specification).

For details regarding ^R1 to ^R4 , M, and Y in formulas (3) and (4), the above-mentioned descriptions apply.

Composition (2) can be a concentrate obtained in step C. Therefore, composition (2) can be produced by step C, etc. In this production method, the water content after concentration can be reduced by concentrating a composition with a pH of 7.0 to 11.0 (preferably 7.0 to 10.5, more preferably 7.0 to 9.0).
Furthermore, composition (2) may be prepared by mixing at least one compound selected from the group consisting of compound (3) and compound (4), and water.

Composition (2) may contain at least one compound selected from the group consisting of compound (3) and compound (4) in an amount of, for example, 1 to 99.9% by mass relative to the mass of composition (2), preferably 10 to 99.9% by mass, and more preferably 50 to 99.9% by mass.

When composition (2) contains compound (3) and compound (4), the content of compound (3) can be, for example, 0.1 to 99.9% by mass, preferably 50 to 99.9% by mass, and more preferably 75 to 99.9% by mass, relative to the total of compound (3) and compound (4).

Composition (2) may contain water in an amount of, for example, 1 ppm to 400 ppm relative to the mass of composition (2), preferably 1 ppm to 200 ppm, more preferably 1 ppm to 100 ppm, and even more preferably 1 ppm to 50 ppm.

Composition (2) may contain, in addition to water, at least one compound selected from the group consisting of compound (3) and compound (4). Examples of other components include alkali metal or alkaline earth metal salts of hydrogen halides, alkali metal or alkaline earth metal salts of inorganic acids, etc. Composition (2) may contain the other components in an amount of, for example, 0.1 to 50% by mass relative to the mass of composition (2).

By subjecting composition (2) to step D and heating it, compound (3) is decarboxylated, producing high-purity compound (1), while the formation of HF adducts, which are by-products and difficult to separate from compound (1), is reduced. This is presumed to be due to the very low water content of composition (2). Composition (2) is useful as a source of compound (1).

The amount of water contained in compositions (1) and (2) can be determined by the Karl Fischer method (coulometric titration).

While the embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims.

The following describes in more detail one embodiment of this disclosure with reference to examples, but this disclosure is not limited thereto.

In the examples, pH was measured using a HORIBA F-74 benchtop pH/water quality analyzer, and water content was measured using the Karl Fischer method (coulometric titration), expressed as the amount relative to the mass of the composition.

The symbols and abbreviations used in the examples, etc., are used with the following meanings.
GC: Gas chromatography Compounds a-f: Compounds represented by the following formulas

Manufacturing Example 1: Manufacturing of Compounds a and b. A crude compound containing compound a was synthesized according to the descriptions in Examples 1 and 2 of Patent Document 1, and a crude compound containing compound b was synthesized according to the descriptions in Examples 1 to 3 of Patent Document 1. These were used as raw materials for the Comparative Example and the Example.

Comparative Example 1
7.2 g (74% purity) of the crude compound a was added to the reaction vessel, and 12.7 g of potassium carbonate and 28 g of 1,2-dimethoxyethane were added, and the mixture was stirred at 60°C for 2 hours to obtain the reaction solution. The reaction solution was filtered and concentrated, and analyzed by NMR, which revealed a concentrate containing 7.2 g of compound e (yield 46%). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 12.0. The obtained concentrate was added to the reactor and heated at 200°C for 4 hours and then at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC, yielding a product containing compound c in a yield of 55% (compound c:compound d = 92:8 (molar ratio)).

Comparative Example 2
12.1 g (95% purity) of the crude compound a was added to the reaction vessel, and 5.3 g of potassium carbonate and 10 g of water were added. The mixture was stirred at 0-10°C for 3 hours to obtain the reaction solution. The reaction solution was filtered and concentrated, and analyzed by NMR. The concentrate contained 13.0 g of compound e (yield 98%). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 12.0. The obtained concentrate was added to the reactor and heated at 200°C for 4 hours and then at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result was a product containing compound c in a yield of 63% (compound c:compound d = 88:12 (molar ratio)).

Comparative Example 3
41 g of crude compound b (98% purity) was added to the reaction vessel, and 7.4 g of potassium hydroxide and 42 g of methanol were added. The mixture was stirred at 20°C for 1 hour to obtain the reaction solution. The reaction solution was filtered and concentrated, and analyzed by NMR. The concentrate contained 44.8 g of compound e (yield 95%). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 13.6. The obtained concentrate was added to the reactor and heated at 200°C for 4 hours and then at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result was a product containing compound c in 72% yield (compound c:compound d = 90:10 (molar ratio)).

Example 1
7.2 g (74% purity) of crude compound a was added to the reaction vessel, and 2.4 g of potassium carbonate and 28 g of 1,2-dimethoxyethane were added. The mixture was stirred at 60°C for 2 hours to obtain a reaction solution (composition (1): a composition containing compound e, potassium carbonate, KF, and water (860 ppm)). The reaction solution was filtered and concentrated, and analyzed by NMR. The concentrate contained 3.1 g of compound e (yield 51%). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 10.9. The obtained concentrate was added to the reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (2): a composition containing compound e, potassium carbonate, KF, and water (92 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 78% yield (compound c:compound d =>99:< 1 (molar ratio)).

Example 2
7.2 g (74% purity) of crude compound a was added to a reaction vessel, and 12.7 g of potassium carbonate and 28 g of 1,2-dimethoxyethane were added and the mixture was stirred at 60°C for 2 hours to obtain a reaction solution. The reaction solution was filtered, 1 g of the reaction solution was added to 10 g of water, stirred vigorously, and then allowed to stand. The pH of the aqueous phase was checked and found to be 12.0. Hydrofluoric acid was added to the reaction solution to prepare a pH-adjusted solution with a pH of 7.7 (composition (1): a composition containing compound e, potassium carbonate, KF, and water). The pH-adjusted solution was filtered and concentrated to obtain a concentrate. The obtained concentrate was analyzed by NMR and found to contain 2.7 g of compound e (yield 44%). The obtained concentrate was added to a reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (2): a composition containing compound e, potassium carbonate, KF, and water (63 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 85% yield (compound c:compound d =>99:< 1 (molar ratio)).

Example 3
12.1 g (95% purity) of crude compound a was added to a reaction vessel, and 5.2 g of potassium carbonate and 10 g of water were added. The mixture was stirred at 0-10°C for 3 hours to obtain a reaction solution (composition (1): a composition containing compound e, potassium carbonate, KF, and water). The reaction solution was filtered and concentrated, and analyzed by NMR. The result was a concentrate containing 12.7 g of compound e (98% yield). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 9.6. The obtained concentrate was added to a reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (2): a composition containing compound e, potassium carbonate, KF, and water (70 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 69% yield (compound c:compound d =>99:< 1 (molar ratio)).

Example 4
12.1 g (95% purity) of crude compound a was added to a reaction vessel, and 6.2 g of potassium carbonate and 10 g of water were added. The mixture was stirred at 0-10°C for 3 hours to obtain a reaction solution. The reaction solution was filtered and its pH was confirmed to be 12.0. Hydrofluoric acid was added to the reaction solution to prepare a pH-adjusted solution (composition (1): a composition containing compound e, potassium carbonate, KF, and water) with a pH of 7.9. The pH-adjusted solution was filtered and concentrated to obtain a concentrate. The obtained concentrate was analyzed by NMR and found to contain 12.9 g of compound e (yield 98%). The obtained concentrate was added to a reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (2): a composition containing compound e, potassium carbonate, KF, and water (97 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 70% yield (compound c:compound d =>99:< 1 (molar ratio)).

Example 5
12.1 g (95% purity) of crude compound a was added to a reaction vessel, and 4.0 g of sodium carbonate and 12 g of water were added. The mixture was stirred at 0-10°C for 3 hours to obtain a reaction solution (composition (1): a composition containing compound f, sodium carbonate, NaF, and water). The reaction solution was filtered and concentrated, and analyzed by NMR. The result was a concentrate containing 12.1 g of compound f (95% yield). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 9.9. The obtained concentrate was added to a reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (2): a composition containing compound f, sodium carbonate, NaF, and water (87 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 73% yield (compound c:compound d =>99:< 1 (molar ratio)).

Example 6
41.0 g (98% purity) of crude compound b was added to the reaction vessel, and 7.3 g of potassium hydroxide and 42 g of methanol were added. The mixture was stirred at 20°C for 1 hour to obtain a reaction solution (Composition (1): Composition containing compound b: 1.6 GC%, compound e, potassium hydroxide, and water (2022 ppm)). The reaction solution was filtered and concentrated, and analyzed by NMR. The concentrate contained 43.5 g of compound e (yield 95%). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured to be 10.1. The obtained concentrate was added to the reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (Composition (2): Composition containing compound e, potassium hydroxide, and water (121 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 78% yield (compound c:compound d =>99:< 1 (molar ratio)).

Example 7
41.0 g (98% purity) of crude compound b was added to a reaction vessel, and 8.4 g of potassium hydroxide and 42 g of methanol were added. The mixture was stirred at 20°C for 1 hour to obtain a reaction solution. The reaction solution was filtered, and 1 g of the reaction solution was added to 10 g of water. After vigorous stirring, the mixture was allowed to stand, and the pH of the aqueous phase was checked to be 12.0. Hydrofluoric acid was added to the reaction solution to prepare a pH-adjusted solution (composition (1): compound b: 2.0 GC%, compound e, potassium hydroxide, water) with a pH of 7.5. The pH-adjusted solution was filtered and concentrated to obtain a concentrate. The obtained concentrate was analyzed by NMR and found to contain 43.0 g of compound e (yield 95%). The obtained product was added to a reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (2): composition containing compound e, potassium hydroxide, and water (54 ppm)) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour. The product was collected in a -78°C trap and analyzed by NMR and GC. The result showed that a product containing compound c was obtained in 80% yield (compound c:compound d =>99:< 1 (molar ratio)).

Claims (5)

Formula (3):
[In the formula, ^R1 is a trifluoromethyl group or a fluorine atom, R2 ^to R4 ^are all fluorine atoms , and M is a potassium atom or a sodium atom.]
Compounds represented by formula (4):
[In the formula, Y is a hydrogen atom or a C1 -C3 alkyl group, and ^R1 to ^R4 are the same as described above.]
A composition comprising at least one compound selected from the group consisting of compounds represented by , and at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals,
The composition is an organic solvent or solid containing at least one compound selected from the group consisting of compounds represented by formula (3) and compounds represented by formula (4), and the pH of an aqueous solution obtained by adding water to the composition is in the range of 7.0 to 11.0.
The water content of the composition is 1 ppm to 3000 ppm relative to the mass of the composition.
The organic solvent is at least one selected from the group consisting of methanol, ethanol, n-propanol, isopropanol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, diethyl ether, diisopropyl ether, dioxane, tetrahydrofuran, 1,2-dimethoxyethane, and crown ether.
The base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, sodium bicarbonate, potassium bicarbonate, potassium hydroxide, sodium hydroxide, potassium methoxide, sodium methoxide, potassium ethoxide, and sodium ethoxide.
composition. The composition according to claim 1 , wherein the pH of the aqueous solution is in the range of 7.0 to 10.5. The composition according to claim 1 or 2 , wherein the pH of the aqueous solution is in the range of 7.0 to 9.0. The composition according to any one of claims 1 to 3 , wherein the water content is 1 ppm to 1000 ppm relative to the mass of the composition. The composition according to any one of claims 1 to 4 , wherein the water content is 1 ppm to 100 ppm relative to the mass of the composition.