Method for producing fluorine-containing dioxolanes and compositions useful for the production thereof

Abstract

To provide a composition suitable for producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure with reduced by-production of HF adducts.SOLUTION: Provided is a composition comprising at least one compound selected from the group consisting of compounds represented by formula (3) and formula (4), and carbon dioxide [where, R1 to R4 each represent F or a C1-C7 fluoroalkyl group, M represents an alkali metal or alkaline earth metal atom, and Y represents H or an alkyl group in which one or more H atoms may be substituted with F].SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present disclosure relates to a method for producing a fluorine-containing dioxolane and a composition useful for the production thereof. [Background technology]

[0002] 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 constituting optical fibers. A known method for producing this perfluorodioxolane is, for example, a method using perfluoro(-3,6-bismethyl-1,4-dioxane-2-one as a raw material, as shown in the following formula, and converting it into a 2-COF product, a 2-carboxylate, and a 2-methylene product (e.g., Patent Documents 1 and 2). [ka]

[0003] In this method, a carbonyl fluoride is generally saponified with a base to convert it into a carboxylate, which is then thermally decomposed by heating to produce the desired difluoromethylene. However, if water, which is a proton source, is present during the thermal decomposition of the carboxylate obtained from the carbonyl fluoride, not only the desired difluoromethylene but also an HF adduct in which HF is added to the double bond in the difluoromethylene (for example, 2-hydroperfluoro(2,4-dimethyl-1,3-dioxolane) shown below) is produced. [ka] also be produced, resulting in a decrease in the yield of the desired product.

[0004] Furthermore, since the boiling point of this HF adduct is close to that of the desired difluoromethylene compound, it is not easy to separate the HF adduct from the desired difluoromethylene compound by distillation.

[0005] For this reason, attention has been focused on reducing the amount of water that coexists in carboxylates. For example, Patent Document 3 describes the following: "The present inventors have conducted extensive research into methods for producing perfluoro(2-methylene-4-methyl-1,3-dioxolane), and have found that the method comprises reacting at least one of the raw material perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) and its hydrolysis product 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 then separating the resulting liquid containing perfluoro(2,4-dimethyl-1,3-dioxolan-2-yl)carboxylic acid alkali metal salt or perfluoro(2,4-dimethyl-1,3-dioxolan-2-yl)carboxylic acid alkaline earth metal salt by a separation operation, and then subjecting the resulting liquid to a separation operation, followed by a step of removing water by distillation and then adsorbing water. We have newly discovered that by performing one or more of the selected moisture content reduction treatments and then using it in a liquid phase decarboxylation reaction, it is possible to obtain perfluoro(2-methylene-4-methyl-1,3-dioxolane) in high yield while suppressing the production of 2-hydroperfluoro(2,4-dimethyl-1,3-dioxolane), which is difficult to separate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 166632 [Patent Document 2] International Publication No. 2020 / 230822 [Patent Document 3] International Publication No. 2020 / 095915 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present 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-hydroperfluoro(2,4-dimethyl-1,3-dioxolane)) is suppressed. An object of the present disclosure is to provide a composition containing the carboxylate, which is useful for producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure, with the by-production of an HF adduct suppressed. [Means for solving the problem]

[0008] The present inventors have found that in a production process for a 1,3-dioxolane compound having a 2-(difluoromethylene) structure, when a product (or an aqueous solution of the product if the product is a non-aqueous solution) obtained by saponifying a carbonyl fluoride with a base and converting it into a carboxylate exceeds pH 11.0, adjusting the pH to within the range of 6.0 to 11.0 using carbon dioxide gas can suppress the by-production of an HF adduct by subsequent thermal decomposition of the carboxylate, thereby obtaining a high-purity target product, and can suppress corrosion of a reaction vessel, etc., compared to pH adjustment using an acid such as hydrofluoric acid.

[0009] The present disclosure typically includes the following aspects. Section 1. Formula (1): [ka] [In the formula, R 1 ~R 4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen. A method for producing a compound represented by the formula: A manufacturing method comprising the following steps A, B, C, and D. (Process A) Formula (2): [ka] [wherein X is a hydroxy group, a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms may be substituted by a fluorine atom; R 1 ~R 4 is the same as above.] A compound represented by reacting with at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals; Formula (3): [ka] [wherein M is an alkali metal atom or an alkaline earth metal atom, and R 1 ~R 4 is the same as above.] to obtain a reaction product having a pH in the range above pH 11.0. (Process B) Step B is to add carbon dioxide gas to the reaction product obtained in Step A or a liquid obtained by mixing the reaction product with water to adjust the pH to 6.0 to 11.0, thereby obtaining a pH-adjusted liquid. (Process C) Step C is to concentrate the pH-adjusted solution obtained 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) to produce the compound represented by formula (1). Section 2. R 1 ~R 4 are each independently a fluorine atom, a perfluoro C1-C7 alkyl group, or a perfluoro C1-C7 alkoxy group. Section 3. R 1 is a trifluoromethyl group or a fluorine atom, and R 2 ~R 4 and each of the formulas is a fluorine atom. Section 4. 4. The method according to any one of items 1 to 3, wherein X is a hydroxy group, a fluorine atom, a chlorine atom, methoxy, ethoxy, n-propoxy, i-propoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy. Section 5. 5. The method according to any one of Items 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. Section 6. Items 1 to 5, wherein the pH range of 6.0 to 11.0 in step B is 6.0 to 10.0. 1. The manufacturing method according to any one of the preceding claims. Section 7. 7. The method according to any one of items 1 to 6, wherein the amount of carbon dioxide gas added in step B is 100 to 10,000 mol % based on the content of the compound represented by formula (3) in the reaction product obtained in step A. Section 8. 8. The production method according to any one of Items 1 to 7, wherein the step C and the step D are carried out continuously in the same reactor. Section 9. R 1 is a trifluoromethyl group or a fluorine atom, R 2 ~R 4 are all fluorine atoms, X is a fluorine atom, methoxy, ethoxy, n-propoxy, or i-propoxy; the base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide; M is a potassium atom or a sodium atom, The pH range of 6.0 to 11.0 in step B is 6.5 to 8.5, the amount of carbon dioxide gas added in the step B is 500 to 6000 mol % relative to the content of the compound represented by formula (3) contained in the reaction product obtained in the step A; Item 9. The method for producing according to any one of Items 1 to 8. Section 10. R 1 is a trifluoromethyl group or a fluorine atom, R 2 ~R 4 are all fluorine atoms, X is a fluorine atom or methoxy, the base is at least one compound selected from the group consisting of potassium carbonate and potassium hydroxide, M is a potassium atom, The pH range of 6.0 to 11.0 in step B is 6.9 to 7.9, the amount of carbon dioxide gas added in the step B is 600 to 5000 mol % relative to the content of the compound represented by formula (3) in the reaction product obtained in the step A; Item 10. The method for producing according to any one of Items 1 to 9. Section 11. Formula (3): [ka] [In the formula, R 1 ~R 4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom. A compound represented by the formula: Formula (4): [ka] [wherein Y is a hydrogen atom or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom; R 1 ~R 4 is the same as above.] At least one compound selected from the group consisting of compounds represented by the formula: carbon dioxide A composition comprising: When 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), the pH of the aqueous solution is within the range of 6.0 to 11.0, and when the composition is a non-aqueous solution, the pH of the aqueous solution obtained by adding water to the composition is within the range of 6.0 to 11.0. Section 12. Item 12. The composition according to item 11, further comprising at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals. Section 13. R 1 ~R 4 are each independently a fluorine atom, a perfluoro C1-C7 alkyl group, or a perfluoro C1-C7 alkoxy group. Section 14. R 1 is a trifluoromethyl group or a fluorine atom, and R 2 ~R 4 Item 14. The composition according to any one of items 11 to 13, wherein each of Section 15. 15. The composition according to any one of items 11 to 14, wherein Y is a hydrogen atom, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl. Section 16. Item 16. The composition according to any one of Items 12 to 15, 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 17. Item 17. The composition according to any one of Items 11 to 16, wherein the pH of the aqueous solution is within the range of 6.0 to 10.0. Section 18. Item 17. The composition according to any one of Items 11 to 16, wherein the pH of the aqueous solution is within the range of 6.5 to 10.0. Section 19. R 1 is a trifluoromethyl group or a fluorine atom, R 2 ~R 4 are all fluorine atoms, the base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide; Y is methyl, ethyl, n-propyl, or i-propyl; M is a potassium atom or a sodium atom, The pH of the aqueous solution is within the range of 6.5 to 8.5, The content of the carbon dioxide gas is 0.2 to 30% by mass relative to the mass of the composition. Item 19. The composition according to any one of items 12 to 18. Section 20. R 1 is a trifluoromethyl group or a fluorine atom, R 2 ~R 4 are all fluorine atoms, the base is at least one compound selected from the group consisting of potassium carbonate and potassium hydroxide, Y is methyl, M is a potassium atom, The pH of the aqueous solution is in the range of 6.9 to 7.9, The content of the carbon dioxide gas is 0.3 to 17% by mass relative to the mass of the composition. 20. The composition according to any one of items 12 to 19. Section 21. Formula (3): [ka] [In the formula, R 1 ~R 4are each independently a C1-C7 fluoroalkyl group which may contain a fluorine atom or an etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom. A compound represented by the formula: Formula (4): [ka] [wherein Y is a hydrogen atom or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom; R 1 ~R 4 is the same as above.] At least one compound selected from the group consisting of compounds represented by the formula: A composition containing carbon dioxide gas, A composition having a carbon dioxide gas content of 0.05 to 1000% by mass relative to the mass of the composition. Section 22. Item 22. The composition according to item 21, wherein the carbon dioxide gas content is 0.1 to 500% by mass based on the mass of the composition. Section 23. Item 22. The composition according to item 21, wherein the carbon dioxide gas content is 0.1 to 100% by mass based on the mass of the composition. Section 24. R 1 ~R 4 are each independently a fluorine atom, a perfluoro C1-C7 alkyl group, or a perfluoro C1-C7 alkoxy group. Section 25. R 1 is a trifluoromethyl group or a fluorine atom, and R 2 ~R 4 Both are fluorine atoms. 25. The composition according to any one of items 21 to 24, wherein the composition is a child. Section 26. 26. The composition according to any one of items 21 to 25, wherein Y is a hydrogen atom, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl. Section 27. the composition further comprises a base; R 1 is a trifluoromethyl group or a fluorine atom, R 2 ~R 4 are all fluorine atoms, the base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide; Y is methyl, ethyl, n-propyl, or i-propyl; M is a potassium atom or a sodium atom, The pH of the aqueous solution is within the range of 6.5 to 8.5, The content of the carbon dioxide gas is 0.2 to 30% by mass relative to the mass of the composition. 27. The composition according to any one of items 21 to 26. Section 28. the composition further comprises a base; R 1 is a trifluoromethyl group or a fluorine atom, R 2 ~R 4 are all fluorine atoms, the base is at least one compound selected from the group consisting of potassium carbonate and potassium hydroxide, Y is methyl, M is a potassium atom, The pH of the aqueous solution is in the range of 6.9 to 7.9, The content of the carbon dioxide gas is 0.3 to 17% by mass relative to the mass of the composition. Item 28. The composition according to any one of items 21 to 27. [Effects of the Invention]

[0010] According to the present disclosure, when a 1,3-dioxolane compound having a 2-(difluoromethylene) structure is produced by thermal decomposition of a corresponding carboxylate, the production of a by-product, a 2-hydro-2-trifluoromethyl compound, can be reduced, and a highly pure target product can be produced. According to the present disclosure, after preparing the carboxylate salt, the pH of the reaction solution is adjusted to 6.0 to 11.0 using carbon dioxide gas, thereby avoiding the use of inorganic acids (such as sulfuric acid, hydrochloric acid, and hydrofluoric acid) and suppressing corrosion of equipment (e.g., reaction vessels) caused by inorganic acids. When the composition of the present disclosure is used as a raw material for producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure, it is possible to suppress the production of by-products and obtain a highly pure 1,3-dioxolane compound having a 2-(difluoromethylene) structure. DETAILED DESCRIPTION OF THE INVENTION

[0011] The above summary of the present disclosure is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The remainder of this disclosure more particularly exemplifies example embodiments. In several places in this disclosure, guidance is provided through examples, which examples can be used in various combinations. In each instance, the exemplified group can serve as a non-exclusive and representative group. All publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety.

[0012] term Unless otherwise specified, the symbols and abbreviations used in this specification should be understood to have the meanings commonly used in the technical field to which this disclosure pertains, in accordance with the context of this specification.

[0013] As used herein, the phrase "comprising" is intended to encompass the phrases "consisting essentially of" and "consisting of."

[0014] Unless otherwise specified, the steps, 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.

[0015] In this specification, the notation "Cn-Cm" (where n and m are each numbers) indicates that the number of carbon atoms is n or more and m or less, as would be commonly understood by a person skilled in the art.

[0016] Unless otherwise specified, in this specification, examples of the "alkyl group" include linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, still 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.

[0017] Unless otherwise specified, in this specification, an "alkoxy group" can be a group represented by RO- [wherein R is an alkyl group (e.g., a C1-C10 alkyl group, a C1-C7 alkyl group, a C1-C6 alkyl group, a C1-C4 alkyl group, or a C1-C3 alkyl group)]. Examples of alkoxy groups include methoxy, ethoxy, propoxy (e.g., n-propoxy, isopropoxy), butoxy (e.g., n-butoxy, isobutoxy, sec-butoxy, tert-butoxy), pentyloxy (e.g., n-pentyloxy, tert-pentyloxy, neopentyloxy, isopentyloxy, sec-pentyloxy, 3-pentyloxy), hexyloxy, heptyloxy, octyloxy, nonyloxy, and decyloxy. These include linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4), particularly preferably C1-C3) alkoxy groups, and cyclic C3-C10 (for example, C3-C6, C4-C6, C3-C5, C5-C6) alkoxy groups such as cyclopropoxy, cyclobutoxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, cyclooctyloxy, and adamantyloxy.

[0018] In this specification, unless otherwise specified, a "fluoroalkyl group" refers to an alkyl group in which at least one hydrogen atom is substituted with a fluorine atom, and also includes a perfluoroalkyl group in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms. The fluoroalkyl group can have 1 to 10 carbon atoms, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1 carbon atom, for example. Examples of the fluoroalkyl group include methyl having 1 to 3 fluorine atoms, ethyl having 1 to 5 fluorine atoms, propyl having 1 to 7 fluorine atoms (e.g., n-propyl, isopropyl), and butyl having 1 to 9 fluorine atoms (e.g., n-butyl, isobutyl, se).

[0039] Fluorine atoms include linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4, and particularly preferably C1-C3) fluoroalkyl groups (preferably perfluoroalkyl groups), such as hexyl having 1 to 13 fluorine atoms, heptyl having 1 to 15 fluorine atoms, octyl having 1 to 17 fluorine atoms, nonyl having 1 to 19 fluorine atoms, and decyl having 1 to 21 fluorine atoms. The number of fluorine atoms contained in the fluoroalkyl group may be from 1 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.

[0019] In this specification, unless otherwise specified, a "fluoroalkoxy group" refers to an alkoxy group in which at least one hydrogen atom is substituted with a fluorine atom, and also includes a perfluoroalkoxy group in which all hydrogen atoms of an alkoxy group are substituted with fluorine atoms. The fluoroalkoxy group can have 1 to 10, 1 to 7, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 1 to 2, or 1 carbon atom(s), for example. Examples of the fluoroalkoxy group 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), pentyloxy having 1 to 11 fluorine atoms (e.g., n-pentyloxy, tert-pentyloxy, neopentyloxy, isopentyloxy, sec-pentyloxy, 3-

[0039] Fluoroalkoxy groups include linear or branched C1-C10 (preferably C1-C7, more preferably C1-C6, even more preferably C1-C4, and particularly preferably C1-C3) fluoroalkoxy groups (preferably perfluoroalkoxy groups), such as pentyloxy, 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 contained in the fluoroalkoxy group may be from 1 to the maximum substitutable number, 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.

[0020] In this specification, unless otherwise specified, the term "C1-C7 fluoroalkyl group which may contain etheric oxygen" includes the above-mentioned fluoroalkyl groups having 1 to 7 carbon atoms and C1-C7 fluoroalkyl groups which contain etheric oxygen. In addition, the term "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 have been substituted with fluorine atoms. The C1-C7 fluoroalkyl group containing an etheric oxygen includes a C1-C7 fluoroalkyl group (preferably a perfluoro C1-C alkyl group) having an etheric oxygen "-O-" at its terminal or inside. Therefore, the C1-C7 fluoroalkyl group containing an etheric oxygen can also be referred to as a group having an etheric oxygen atom at the terminal or between the carbon-carbon bond of the C1-C7 fluoroalkyl group. Trifluoromethoxy (CF3-O-) is an example of a fluoroalkyl group having "-O-" at the terminal, and perfluoro(methoxymethyl) (CF3-O-CF2-) is an example of a fluoroalkyl group having "-O-" inside the structure. The number of etheric oxygen atoms contained in the C1-C7 fluoroalkyl group containing an etheric oxygen can be 1, 2, 3, etc., but 1 or 2 is preferred, and 1 is more preferred. The C1-C7 fluoroalkyl group containing an etheric oxygen has 1 to 7 carbon atoms, preferably C1-C6, more preferably C1-C4, and even more preferably C1-C3.

[0021] The C1-C7 fluoroalkyl group containing an etheric oxygen includes a C1-C7 fluoroalkoxy group, a C1-C6 fluoroalkoxytrifluoromethyl group, a C1-C5 fluoroalkoxypentafluoroethyl group, and the like.

[0022] Examples of C1-C7 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), pentyloxy having 1 to 11 fluorine atoms (e.g., n-pentyloxy, tert-pentyloxy, neopentyloxy, isopentyloxy, sec-pentyloxy, 3-pentyloxy), hexyloxy having 1 to 13 fluorine atoms, and heptyloxy having 1 to 15 fluorine atoms.

[0023] The C1-C6 fluoroalkoxytrifluoromethyl group is C1-C6 fluoroalkoxy-CF2-. Examples of C1-C6 fluoroalkoxy are described above in the examples of "fluoroalkoxy group".

[0024] A C1-C5 fluoroalkoxypentafluoroethyl group is a C1-C5 fluoroalkoxy-C2F4-. Examples of C1-C5 fluoroalkoxy are described above in the examples of "fluoroalkoxy group."

[0025] Unless otherwise specified, in this specification, a "C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with fluorine atoms" includes a C1-C3 alkyl group and a C1-C3 alkyl group 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 a C1-C3 alkyl group and a C1-C3 fluoroalkyl group. Furthermore, a C1-C3 alkyl group in which one or more hydrogen atoms are substituted with fluorine atoms includes a perfluoro C1-C3 alkyl group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms. Examples of the C1-C3 alkyl group and the C1-C3 fluoroalkyl group are the same as those described above in the examples of the alkyl group and the examples of the fluoroalkyl group.

[0026] Unless otherwise specified, in this specification, 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 perfluoro C1-C3 alkoxy group in which all hydrogen atoms of the alkoxy group are substituted with fluorine atoms. Examples of the C1-C3 alkoxy group and the C1-C3 fluoroalkoxy group are the same as those described above in the examples of the alkoxy group and the examples of the fluoroalkoxy group.

[0027] In this specification, unless otherwise specified, examples of the "alkali metal" include lithium, sodium, potassium, rubidium, cesium, and francium, preferred examples include lithium, sodium, and potassium, and more preferred examples include sodium and potassium.

[0028] In this specification, unless otherwise specified, examples of the "alkaline earth metal" include beryllium, magnesium, calcium, strontium, barium, and radium, and preferred examples include magnesium and calcium.

[0029] Method for producing a compound represented by formula (1) One embodiment of the present disclosure is a compound of formula (1): [ka] [In the formula, R 1 ~R 4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen. The present invention relates to a method for producing a compound represented by the following formula (sometimes referred to as compound (1) in this specification): The production method includes steps A, B, C, and D. Steps A, C, and D, excluding step B, may be carried out by known methods, for example, in accordance with the methods described in Patent Document 1, Patent Document 2, JP 2005-002014 A, U.S. Pat. No. 3,308,107, or U.S. Pat. No. 6,664,431, all of which are incorporated herein by reference.

[0030] R 1 ~R 4 may each independently be a fluorine atom, a linear or branched C1-C7 fluoroalkyl group, or a linear or branched C1-C7 fluoroalkyl group containing an etheric oxygen. R 1 ~R 4may each independently be a fluorine atom, a linear or branched C1-C6 fluoroalkyl group, or a linear or branched C1-C6 fluoroalkyl group containing an etheric oxygen. R 1 ~R 4 may each independently be a fluorine atom, a linear or branched C1-C5 fluoroalkyl group, or a linear or branched C1-C5 fluoroalkyl group containing an etheric oxygen. R 1 ~R 4 may each independently be a fluorine atom, a linear or branched C1-C4 fluoroalkyl group, or a linear or branched C1-C4 fluoroalkyl group containing an etheric oxygen. R 1 ~R 4 may each independently be a fluorine atom, a linear or branched C1-C3 fluoroalkyl group, or a linear or branched C1-C3 fluoroalkyl group containing an etheric oxygen.

[0031] R 1 ~R 4 may each independently be a fluorine atom, a linear or branched perfluoro C1-C7 alkyl group, or a linear or branched perfluoro C1-C7 alkyl group containing an etheric oxygen. R 1 ~R 4 may each independently be a fluorine atom, a linear or branched perfluoro C1-C6 alkyl group, or a linear or branched perfluoro C1-C6 alkyl group containing an etheric oxygen. R 1 ~R 4 may each independently be a fluorine atom, a linear or branched perfluoro C1-C5 alkyl group, or a linear or branched perfluoro C1-C5 alkyl group containing an etheric oxygen. R 1 ~R 4may each independently be a fluorine atom, a linear or branched perfluoro C1-C4 alkyl group, or a linear or branched perfluoro C1-C4 alkyl group containing an etheric oxygen. R 1 ~R 4 may each independently be a fluorine atom, a linear or branched perfluoro C1-C3 alkyl group, or a linear or branched perfluoro C1-C3 alkyl group containing an etheric oxygen.

[0032] R 1 ~R 4 can each independently be a fluorine atom, a perfluoro C1-C7 alkyl group, or a perfluoro C1-C7 alkoxy group. R 1 ~R 4 may each independently be a fluorine atom, a perfluoro C1-C6 alkyl group, or a perfluoro C1-C6 alkoxy group. R 1 ~R 4 can each independently be a fluorine atom, a perfluoro C1-C5 alkyl group, or a perfluoro C1-C5 alkoxy group. R 1 ~R 4 can each independently be a fluorine atom, a perfluoro C1-C4 alkyl group, or a perfluoro C1-C4 alkoxy group. R 1 ~R 4 can each independently be a fluorine atom, a perfluoro C1-C3 alkyl group, or a perfluoro C1-C3 alkoxy group.

[0033] R 1 ~R 4 wherein at least one group is a fluorine atom, and the remaining groups, when there are a plurality of such remaining groups, may independently be a perfluoro C1-C2 alkyl group or a perfluoro C1-C3 alkoxy group. R 1 ~R 4wherein at least two groups are fluorine atoms, and the remaining groups, when there are a plurality of such remaining groups, may independently be a perfluoro C1-C2 alkyl group or a perfluoro C1-C3 alkoxy group. R 1 ~R 4 In the formula, at least three groups are fluorine atoms, and the remaining groups may be perfluoro C1-C3 alkyl groups or perfluoro C1-C2 alkoxy groups. R 1 ~R 4 In the formula, at least three groups are fluorine atoms, and the remaining groups may be perfluoro C1-C3 alkyl groups. R 1 ~R 4 may all be fluorine atoms. R 1 is a trifluoromethyl group or a fluorine atom, and R 2 ~R 4 may all be fluorine atoms.

[0034] Specific examples of compound (1) include 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), and perfluoro(2 -methylene-4-methoxymethyl-1,3-dioxolane), perfluoro(2-methylene-4-ethoxymethyl-1,3-dioxolane), 2-(difluoromethylene)-3a,4,4,6,6,6a-hexafluorotetrahydrofuro[3,4-d][1,3]dioxole, 2-(difluoromethylene)-3a,4,4,5,5,6,6,7,7,7a-decafluorohexahydrobenzo[d][1,3]dioxole, perfluoro(2-methylene-1,3-dioxolane), Perfluoro(2-methylene-4-methyl-1,3-dioxolane) is preferred.

[0035] Process A In step A, the compound of formula (2): [ka] [wherein X is a hydroxy group, a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms may be substituted by a fluorine atom; R 1 ~R 4 is the same as above.] (hereinafter, sometimes referred to as compound (2)) with at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals, Formula (3): [ka] [wherein M is an alkali metal atom or an alkaline earth metal atom, and R 1 ~R 4 is the same as above.] (sometimes referred to as compound (3) in this specification) to obtain a reaction product having a pH in the range exceeding pH 11.0.

[0036] 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.

[0037] X can be a hydroxy group, a fluorine atom, a chlorine atom, or a C1-C3 alkoxy group in which one or more hydrogen atoms may be substituted with fluorine atoms. X can be a hydroxy group, a fluorine atom, a chlorine atom, methoxy, ethoxy, n-propoxy, i-propoxy, trifluoromethoxy, or 2,2,2-trifluoroethoxy. X can be a hydroxy 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 fluorine atoms. 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, ethoxy, n-propoxy, or i-propoxy. X can be a fluorine atom, methoxy, or trifluoromethoxy. X can be a fluorine atom or methoxy.

[0038] 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-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. i-propyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid trifluoromethyl ester, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid 2,2,2-trifluoroethyl ester. Suitable 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.

[0039] The base includes hydroxides, carbonates, and alkoxides of alkali metals, and hydroxides, carbonates, and alkoxides of alkaline earth metals, and may be used singly 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.

[0040] The base is preferably at least one selected from the group consisting of potassium carbonate, sodium carbonate, magnesium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, 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. The base is even more preferably at least one selected from the group consisting of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide. The base is particularly preferably at least one selected from the group consisting of potassium carbonate and sodium hydroxide.

[0041] Compound (3) is a carboxylate of compound (2) corresponding to the base used in step A. Specific examples and preferred specific examples of compound (3) are carboxylates corresponding to the specific examples and preferred specific examples of compound (2) above, respectively. M can be an alkali metal atom or an alkaline earth metal atom. M is preferably an alkali metal atom, more preferably a potassium atom or a sodium atom, and even more preferably a potassium atom. M can be a group corresponding to the base used in step A. Thus, if the base is a potassium salt, M can be a potassium atom.

[0042] Step A may be carried out in the presence or absence of a solvent. The solvent may be water or an organic solvent, and one solvent may be used alone or two or more solvents may be used in combination.

[0043] Examples of the organic solvent include alkyl alcohol solvents, ether solvents, aromatic solvents, saturated hydrocarbon solvents, nitrile solvents, sulfoxide solvents, and halogenated hydrocarbon solvents. Suitable examples of the organic solvent include alkyl alcohol solvents, ether solvents, halogenated hydrocarbon solvents, and nitrile solvents.

[0044] Examples of alkyl alcohol solvents include linear or branched C1-C10 alkyl alcohols. The alcohol is preferably a linear or branched C1-5 alkyl alcohol, more preferably a linear or branched C1-4 alkyl alcohol, even more preferably methanol, ethanol, n-propanol, isopropanol, n-butyl alcohol, sec-butyl alcohol, or tert-butyl alcohol, and particularly preferably methanol or ethanol.

[0045] Specific preferred examples of the ether solvent include 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 ethers.

[0046] 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-dicyanobutane, 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, chlorobenzene, and perfluorohexane.

[0047] 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-dicyanobutane, methylene chloride, chloroform, tetrahydrofuran, perfluorohexane, and acetonitrile.

[0048] The amount of the base used in step A can be within a range of 0.05 to 10 mol, a range of 0.1 to 10 mol, or a range of 0.1 to 5 mol, per 1 mol of compound (2), preferably within a range of 0.5 to 10 mol, more preferably within a range of 0.5 to 5 mol. The amount of base is preferably an amount that causes the pH of the reaction product obtained in step A or a liquid obtained by mixing the reaction product with water to exceed 11.0.

[0049] When a solvent is used in step A, the amount of the solvent used may be an amount that can function as a solvent based on common technical knowledge, etc.

[0050] The reaction temperature in step A may be preferably within the range of -50 to 120°C, more preferably within the range of -20 to 100°C, and even more preferably within the range of -10 to 70°C.

[0051] The reaction time for step A is not particularly limited as long as the target substance is produced, but is preferably within the range of 0.1 to 48 hours, more preferably within the range of 0.1 to 24 hours, and even more preferably within the range of 0.1 to 12 hours.

[0052] 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 or non-aqueous solution. Aqueous solutions include aqueous solutions of compound (3). Non-aqueous solutions include organic solvents containing compound (3) and solids containing compound (3). When water or a mixture of water and other solvents is used as the solvent in step A, the reaction The product may be obtained as an aqueous solution of compound (3). When an organic solvent is used as the solvent in step A, the reaction product can be obtained as an organic solvent (including a slurry) containing compound (3). When no solvent is used in step A, the reaction product can be obtained as a solid (including a slurry) containing compound (3). The pH of the reaction product may range above 11.0 and may range up to 12.0 or higher. The reaction product is subjected to the next step B.

[0053] Process B Step B is a step of adjusting the pH of the reaction product (which may be a liquid) obtained in Step A, which has a pH in the range exceeding 11.0, to a range of 6.0 to 11.0 using carbon dioxide gas before subjecting it to the subsequent concentration step, Step C. This pH may be 6.0 to 10.0, 6.5 to 10.0, etc., preferably 6.5 to 9.0, even more preferably 6.5 to 8.5, and particularly preferably 6.9 to 7.9. Prior to the pH adjustment, the pH of the reaction product obtained in Step A may be measured to confirm that the pH of the reaction product exceeds 11.0. The pH-adjusted reaction product (sometimes referred to as a "pH-adjusted solution") is subjected to Step C.

[0054] Explain pH measurement. pH can be measured using pH test paper, a pH meter (e.g., a HORIBA benchtop pH / water quality analyzer) F-74), or a value determined by titration with a pH indicator, preferably p This is the value specified by the H meter. The reaction product obtained in step A may be a liquid or a solid. In measuring the pH of the reaction product obtained in step A to confirm the pH, it is not necessary to measure the pH of the entire reaction product obtained in step A, and the pH may be measured on a portion of the reaction product. When the reaction product obtained in step A is an aqueous solution of compound (3), a part or all of this aqueous solution can be subjected to pH measurement. When the reaction product obtained in step A is an organic solvent containing compound (3) (including an organic solvent solution in which compound (3) is dissolved (e.g., an alcohol solution in which compound (3) is dissolved)), the same applies below.), a mixture obtained by mixing water with part or all of this organic solvent can be subjected to pH measurement. Note that when the mixture separates into an aqueous phase and an organic phase upon standing, the aqueous phase can be subjected to pH measurement. When the reaction product obtained in step A is a solid containing compound (3), a liquid obtained by mixing water with part or all of this solid to dissolve compound (3) can be subjected to pH measurement.

[0055] Carbon dioxide gas is used to adjust the pH. The use of carbon dioxide gas suppresses the by-production of HF adducts (e.g., 2-hydroperfluoro(2,4-dimethyl-1,3-dioxolane)) in which HF is added to the double bond in the difluoromethylene compound, more than other pH adjustment treatments (e.g., acidic solution treatment). The target of the carbon dioxide gas treatment is not particularly limited as long as the pH can be adjusted by the carbon dioxide gas treatment. The reaction product may be subjected to the pH adjustment treatment as it is, or the filtrate obtained by filtering the reaction product may be subjected to the pH adjustment treatment, or a concentrate obtained by concentrating the reaction product may be subjected to the pH adjustment treatment. When the reaction product obtained in step A is an aqueous solution of compound (3), this aqueous solution can be subjected to carbon dioxide gas treatment. When the reaction product obtained in step A is an organic solvent solution in which compound (3) is dissolved, this organic solvent solution can be subjected to carbon dioxide gas treatment. When the reaction product obtained in step A is an organic solvent containing compound (3), a mixture obtained by mixing this organic solvent with water, or an aqueous phase obtained by separating the mixture, is subjected to carbon dioxide gas treatment. obtain. When the reaction product obtained in step A is a solid containing compound (3), this solid can be mixed with water or an organic solvent to dissolve compound (3), and the resulting solution can be subjected to carbon dioxide gas treatment.

[0056] Examples of carbon dioxide treatment methods include bubbling, which supplies carbon dioxide gas into the target liquid, pressurizing carbon dioxide gas into the target liquid in a sealed container, and adding dry ice (which may be powdered or solid) during the reaction and utilizing the vaporized carbon dioxide gas. However, the method is not limited as long as the pH of the target substance can be adjusted to within the desired range using carbon dioxide gas. The conditions for the carbon dioxide gas treatment are not limited as long as the pH of the target substance can be adjusted to within a desired range. The amount of carbon dioxide gas added can be, for example, 100 to 10,000 mol %, 300 to 10,000 mol %, etc., preferably 300 to 6,000 mol %, even more preferably 500 to 6,000 mol %, and particularly preferably 600 to 5,000 mol %, relative to the content of the compound represented by formula (3) in the reaction product obtained in step A. The temperature for the carbon dioxide gas treatment may be, for example, -100 to 100°C, preferably -10 to 40°C. The time for the carbon dioxide gas treatment may be, for example, 0.1 to 72 hours, preferably 0.5 to 24 hours. Carbonation can be carried out under elevated pressure, reduced pressure, or atmospheric pressure. The pH-adjusted solution obtained by the carbon dioxide gas treatment is subjected to the next step C.

[0057] Process C In step C, the pH-adjusted solution obtained in step B is concentrated.

[0058] The concentration step can be carried out in accordance with a known concentration method. Examples of concentration methods include vacuum distillation, drying, extraction, precipitation, distillation, chromatography, etc., which can be used alone or in combination of two or more. Preferred concentration methods are vacuum distillation and drying. Examples of the concentration conditions include vacuum distillation at 0 to 150°C and drying at 0 to 150°C. The concentrate obtained by concentration can be in liquid, gel, or solid form. In the concentration step, the compound (3) is concentrated until its concentration reaches, for example, 90% by mass or more, 92% by mass or more, or 94% by mass or more.

[0059] 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 to produce compound (1) in high purity. Step D can be carried out in the reactor in which the concentration treatment in step C was carried out.

[0060] 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 is a solvent that can decarboxylate compound (3). The organic solvent may be a solvent known to be usable for decarboxylation of compound (3). Examples and preferred examples of organic solvents are the same as those of the organic solvent in Step A. Specific preferred examples of the organic solvent include 1,2-dimethoxyethane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, 1,4-dicyanobutane, and acetonitrile.

[0061] The amount of organic solvent used in step D may be an amount that can function as a solvent based on common technical knowledge, etc.

[0062] When the object to be heated contains a solvent, the reaction temperature in step D is preferably in the range of 50 to 400°C, more preferably in the range of 70 to 300°C, and even more preferably in the range of 100 to 200°C. When the object to be heated does not contain a solvent, the temperature may be preferably in the range of 100 to 400°C, more preferably in the range of 150 to 400°C, and even more preferably in the range of 150 to 350°C.

[0063] The reaction time in step D is not particularly limited as long as compound (1) is produced, but may be preferably within a range of 0.1 to 48 hours, more preferably within a range of 0.1 to 24 hours, and even more preferably within a range of 0.1 to 12 hours.

[0064] The reaction of step D can be carried out in the presence or absence of an inert gas (eg, nitrogen gas), and is preferably carried out in the absence of an inert gas.

[0065] Step D can be carried out under reduced pressure, atmospheric pressure, or elevated pressure.

[0066] Compound (1) produced in step D can be isolated or purified, if desired, by a conventional method such as extraction, dissolution, concentration, precipitation, dehydration, adsorption, distillation, rectification, chromatography, or a combination thereof.

[0067] Composition (1) One embodiment of the present disclosure is a compound of formula (3): [ka] [In the formula, R 1 ~R 4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom. A compound represented by the formula: Formula (4): [ka] [wherein Y is a hydrogen atom or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom; R 1 ~R 4 is the same as above.] At least one compound selected from the group consisting of compounds represented by the formula (4) (sometimes referred to as compound (4) in this specification), and A composition containing carbon dioxide gas, When the composition is an aqueous solution of at least one compound selected from the group consisting of compound (3) and compound (4), the pH of the composition (aqueous solution) is within the range of 6.0 to 11.0, and when the composition is a non-aqueous solution, the pH of the aqueous solution obtained by adding water to the composition (non-aqueous solution) is within the range of 6.0 to 11.0 (sometimes referred to as composition (1) in this specification).

[0068] The composition may be an aqueous or non-aqueous solution. The aqueous solution contains 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) (an organic solvent solution in which at least one compound selected from the group consisting of compounds (3) and (4) is dissolved (for example, an alcohol solution in which at least one compound selected from the group consisting of compounds (3) and (4) is dissolved)) (the same applies hereinafter). If the composition is an aqueous solution, its pH ranges from 6.0 to 11.0, and if it is a non-aqueous solution, the pH of the aqueous solution obtained by adding water to the composition may be in the range of 6.0 to 11.0. The pH of either solution may be 6.0 to 10.0, 6.5 to 10.0, etc., preferably 6.5 to 9.0, even more preferably 6.5 to 8.5, and particularly preferably 6.9 to 7.9. When the non-aqueous solution is an organic solvent solution containing at least one compound selected from the group consisting of compounds (3) and (4), the pH of the solution may be within the range of 6.0 to 11.0, such as 6.0 to 10.0 or 6.5 to 10.0, preferably 6.5 to 9.0, more preferably 6.5 to 8.5, and particularly preferably 6.9 to 7.9. When the non-aqueous solution is an organic solvent containing at least one compound selected from the group consisting of compounds (3) and (4), the pH of the mixture obtained by mixing this organic solvent with water or the aqueous phase obtained by separating the mixture may be within the range of 6.0 to 11.0. The pH may be 6.0 to 10.0, 6.5 to 10.0, etc., preferably 6.5 to 9.0, even more preferably 6.5 to 8.5, and particularly preferably 6.9 to 7.9.

[0069] Y can be a hydrogen atom or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom. 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 have been replaced 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.

[0070] Examples of Y include a hydrogen atom, methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, 2,2,2-trifluoroethyl, pentafluoroethyl, perfluoro-n-propyl, and perfluoro-i-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 can be methyl, ethyl, n-propyl, i-propyl, trifluoromethyl, or 2,2,2-trifluoroethyl. Y can be methyl, ethyl, n-propyl, or i-propyl. Y can be methyl.

[0071] Compound (3), Compound (4), R 1 ~R 4 For details of and M, the above explanations about them apply.

[0072] 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, 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, Examples include 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid i-propyl ester, 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid trifluoromethyl ester, and 4,4,5-trifluoro-2,5-bis(trifluoromethyl)-1,3-dioxolane-2-carboxylic acid 2,2,2-trifluoroethyl ester. Specific preferred 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.

[0073] Since compound (3) is produced by step A, composition (1) can be the pH-adjusted solution obtained after the carbon dioxide gas treatment. Therefore, this composition can be produced, for example, by step B. Alternatively, this composition can also be produced by mixing at least one compound selected from the group consisting of compound (3) and compound (4) with carbon dioxide gas.

[0074] 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, 0.1 to 99.9 mass%, preferably 1 to 90 mass%, more preferably 5 to 80 mass%, based on the mass of composition (1).

[0075] When composition (1) contains compound (3) and compound (4), the content of compound (3) can be, for example, 0.1 to 99.9 mass%, preferably 50 to 99.9 mass%, and more preferably 75 to 99.9 mass%, based on the total of compound (3) and compound (4).

[0076] Composition (1) can contain carbon dioxide gas in an amount of, for example, 0.05 to 1000 mass%, 0.1 to 500 mass%, etc., based on the mass of composition (1), preferably 0.1 to 100 mass%, more preferably 0.2 to 50 mass%, even more preferably 0.2 to 30 mass%, and particularly preferably 0.3 to 17 mass%.

[0077] The composition (1) may contain water and / or an organic solvent. For details of the organic solvent, the description of the organic solvent explained in the production method above can be applied. The composition (1) can contain water in an amount of, for example, 5 to 90 mass %, preferably 10 to 80 mass %, and more preferably 10 to 70 mass %, based on the mass of the composition (1). The composition (1) can contain, for example, 5 to 90 mass % of the organic solvent, preferably 10 to 80 mass %, and more preferably 10 to 70 mass %, based on the mass of the composition (1).

[0078] Composition (1) may contain other components in addition to at least one compound selected from the group consisting of compound (3) and compound (4) and carbon dioxide gas. Examples of other components include a base, an alkali metal or alkaline earth metal salt of a hydrogen halide, and an alkali metal or alkaline earth metal salt of an inorganic acid. The description of the base in the production method of the present disclosure can be applied to the base. Composition (1) may contain other components in an amount of, for example, 0.1 to 30 mass %, 0.1 to 20 mass %, etc., relative to the mass of composition (1).

[0079] Composition (1) is subjected to step C to be concentrated, and the concentrate is heated in step D to decarboxylate compound (3) and produce highly pure compound (1). At this time, the production of a by-product, an HF adduct, which is not easily separated from compound (1), is reduced. This is because composition (1) contains carbon dioxide gas and the pH of composition (1) is 6.0 to 11.0, 6.0 to 12.0, or 6.0 to 13.0. This is presumably because the molecular weight is within the range of 10.0, 6.5 to 10.0, 6.5 to 9.0, 6.5 to 8.5, or 6.9 to 7.9. Composition (1) is useful as a supply source of compound (1).

[0080] Composition (2) One embodiment of the present disclosure is a compound of formula (3): [ka] [In the formula, R 1 ~R 4 are each independently a fluorine atom or a C1-C7 fluoroalkyl group which may contain an etheric oxygen, and M is an alkali metal atom or an alkaline earth metal atom. A compound represented by the formula: Formula (4): [ka] [wherein Y is a hydrogen atom or a C1-C3 alkyl group in which one or more hydrogen atoms may be substituted with a fluorine atom; R 1 ~R 4 is the same as above.] At least one compound selected from the group consisting of compounds represented by the formula: A composition containing carbon dioxide gas, The carbon dioxide gas content is 0.05 to 1000% by mass relative to the mass of the composition (sometimes referred to as composition (2) in this specification).

[0081] Compound (3), Compound (4), R 1 ~R 4 For details of M and Y, the above explanations about them apply.

[0082] Since compound (3) is produced by step A, composition (1) can be the pH-adjusted solution obtained after the carbon dioxide gas treatment or the concentrate obtained after the concentration treatment. Therefore, this composition can be produced, for example, by step B or C. This composition can also be produced by mixing at least one compound selected from the group consisting of compound (3) and compound (4) with carbon dioxide gas.

[0083] Composition (2) can 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 mass%, preferably 10 to 99.9 mass%, more preferably 50 to 99.9 mass%, based on the mass of composition (2).

[0084] When composition (2) contains compound (3) and compound (4), the content of compound (3) can be, for example, 0.1 to 99.9 mass%, preferably 50 to 99.9 mass%, more preferably 75 to 99.9 mass%, based on the total of compound (3) and compound (4).

[0085] Composition (2) can contain carbon dioxide gas in an amount of, for example, 0.1 to 10,000 mol %, preferably 0.1 to 7,000 mol %, more preferably 0.1 to 5,000 mol %, and even more preferably 1 to 5,000 mol %, based on the content of compound (3). Composition (2) may contain carbon dioxide gas in an amount of, for example, 0.05 to 1000 mass%, 0.1 to 500 mass%, etc., based on the mass of composition (2), preferably 0.1 to 100 mass%, more preferably 0.2 to 50 mass%, even more preferably 0.2 to 30 mass%, and particularly preferably 0.3 to 17 mass%.

[0086] Composition (2) may contain water and / or an organic solvent. For details of the organic solvent, the description of the organic solvent explained in the production method above can be applied. The composition (2) can contain water in an amount of, for example, 0.001 to 90 mass %, preferably 0.001 to 80 mass %, and more preferably 0.001 to 70 mass %, based on the mass of the composition (2). Composition (2) can contain an organic solvent in an amount of, for example, 0.001 to 90 mass %, preferably 0.001 to 80 mass %, and more preferably 0.001 to 70 mass %, based on the mass of composition (2).

[0087] Composition (2) may contain other components in addition to at least one compound selected from the group consisting of compound (3) and compound (4) and carbon dioxide gas. Examples of other components include a base, an alkali metal or alkaline earth metal salt of a hydrogen halide, and an alkali metal or alkaline earth metal salt of an inorganic acid. The description of the base in the production method of the present disclosure can be applied to the base. Composition (2) may contain other components in an amount of, for example, 0.1 to 30 mass %, 0.1 to 20 mass %, etc., relative to the mass of composition (2).

[0088] Composition (2) is subjected to step C to be concentrated, and the concentrate is heated in step D. Alternatively, if composition (2) is sufficiently concentrated, composition (2) is heated in step D. This decarboxylates compound (3) to produce highly pure compound (1). During this process, the production of a by-product, an HF adduct, which is difficult to separate from compound (1), is reduced. This is presumably because composition (2) contains carbon dioxide gas, and the carbon dioxide gas content is 0.05 to 1000 mass% relative to the mass of composition (2). Composition (2) is useful as a supply source of compound (1).

[0089] In the present disclosure, the amount of carbon dioxide can be determined by the Orsat method, gas absorption method, electrical conductivity method, thermal conductivity method, infrared absorption method, gas chromatography method, mass spectrometry, ion electrode method, measurement of gas phase pressure and liquid phase temperature, conversion method from pH and alkalinity, etc. When the amount of carbon dioxide differs depending on the determination method, the amount of carbon dioxide determined by measurement of gas phase pressure and liquid phase temperature, specifically by the method described in the Examples, is used.

[0090] Although the embodiments have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the claims. [Example]

[0091] Hereinafter, one embodiment of the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited thereto.

[0092] In the examples, pH measurements were performed using a HORIBA F-74 benchtop pH / water quality analyzer. The amount of carbon dioxide was calculated from the gas phase pressure and liquid phase temperature and expressed as the amount (mol%) relative to the amount of compound (3). Specifically, the amount of carbon dioxide was calculated by subtracting the amount of carbon dioxide when the temperature and pressure in the reactor became roughly constant after introduction from the initial amount of carbon dioxide introduced into the reactor (amount of carbon dioxide added). The latter amount of carbon dioxide was calculated based on the temperature and pressure in the reactor. and calculated by measuring the volume of space.

[0093] The symbols and abbreviations in the examples have the following meanings: GC: Gas chromatography Compounds a to e: Compounds represented by the following formulae [ka]

[0094] Production Example 1: Production of Compounds a and b A crude product (purity 95%) containing compound a was synthesized according to the description in Reference Example 1 of Patent Document 3, and a crude product (purity 98%) containing compound b was synthesized according to the description in Example 5 of Patent Document 1, and these were used as raw materials in the comparative examples and examples.

[0095] Comparative Example 1 12.1 g of crude material containing compound a (95% purity) was added to a 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 a reaction solution. The reaction solution was filtered, concentrated, and analyzed by NMR. This resulted in a concentrate containing 12.6 g of compound e (98% yield). 1 g of the concentrate was dissolved in 50 g of water, and the pH was measured, which was 12.0. The resulting 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. A product containing compound c was obtained in a 63% yield (compound c:compound d = 88:12 (molar ratio)).

[0096] Comparative Example 2 41 g of crude material containing compound b (98% purity) was added to a reaction vessel, and 7.4 g of potassium hydroxide and 42 g of methanol were further added and stirred at 20 °C for 1 hour to obtain a reaction solution. The reaction solution was filtered, concentrated, and analyzed by NMR, revealing a concentrate containing 42.7 g of compound e (yield 95%). 1 g of this concentrate was dissolved in 50 g of water and the pH was measured, which was found to be 13.6. The resulting concentrate was added to the reactor and heated at 200 °C for 4 hours and 300 °C for 1 hour. The product was collected in a -78 °C trap and analyzed by NMR and GC. A product containing compound c was obtained in a 72% yield (compound c:compound d = 90:10 (molar ratio)).

[0097] Reference example 1 12.1 g of crude material containing compound a (95% purity) was added to a reaction vessel, followed by 6.2 g of potassium carbonate and 10 g of water, and the mixture was stirred at 0 to 10°C for 3 hours to obtain a reaction solution. The entire reaction solution was filtered, and the pH was confirmed to be 12.0. Hydrofluoric acid was added to the reaction solution to prepare a pH-adjusted solution with a pH of 7.9 (composition (A): a composition containing compound e, potassium carbonate, KF, and water). The pH-adjusted solution was filtered and concentrated to obtain a concentrate. NMR analysis of the resulting concentrate revealed that it contained 12.6 g of compound e (yield: 98%). After the reaction, the interior of the stainless steel reactor was inspected and corroded. The resulting concentrate was added to the reactor and vacuum-dried at 140°C for 15 hours. After confirming that a highly concentrated product (composition (B): 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. The product was analyzed by NMR and GC, and as a result, it was found that a product containing compound c was obtained in a yield of 70% (compound c:compound d =>99:<1 (molar ratio)).

[0098] Reference example 2 41.0 g (purity 98%) of crude material containing compound b was added to a reaction vessel, and 8.4 g of potassium hydroxide and 42 g of methanol were further added and stirred at 20 °C for 1 hour to obtain a reaction solution. The entire reaction solution was filtered, and 1 g of the reaction solution was added to 10 g of water. After vigorously stirring and allowing to stand, the pH of the aqueous phase was confirmed to be pH 12.0. Hydrofluoric acid was added to the reaction solution to prepare a pH-adjusted solution (composition (C): 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. NMR analysis of the obtained concentrate revealed that it contained 42.8 g of compound e (yield 95%). After the reaction, the interior of the SUS reactor was inspected and corrosion of the vessel surface was confirmed. The resulting product was added to a reactor and vacuum dried at 140°C for 15 hours. After confirming that it had become a highly concentrated product (composition (D): a composition containing compound e, potassium hydroxide, and water (54 ppm)), 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. Analysis of the product by NMR and GC showed that a product containing compound c was obtained in an 80% yield (compound c:compound d = >99:<1 (molar ratio)).

[0099] Example 1 11.5 g of crude material containing compound a (95% purity) was added to a reaction vessel, followed by 5.5 g of potassium carbonate and 10 g of water, and the mixture was stirred at 0 to 10°C for 3 hours to obtain a reaction solution. The entire reaction solution was filtered, and the pH was confirmed to be 12.0. The filtrate was transferred to a 2.0 L stainless steel pressure vessel, and 8.9 g (600 mol%) of carbon dioxide was added and stirred for 1 hour to prepare a pH-adjusted solution with a pH of 7.9. The temperature inside the reaction vessel was 25°C and the pressure was 0.25 MPaG. The resulting pH-adjusted solution was concentrated, and NMR analysis of the concentrate revealed the presence of 11.6 g of compound e (95% yield). After the reaction, the interior of the stainless steel reactor was inspected, and no corrosion was observed on the vessel surface. The resulting concentrate was added to the reactor and vacuum-dried at 140°C for 15 hours (Step C). After confirming that a highly concentrated product (water content 100 ppm or less) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour (Step D). The product was collected in a trap at -78°C. Analysis of the product by NMR and GC revealed that a product containing compound c was obtained in a yield of 78% (compound c:compound d =>99:<1 (molar ratio)).

[0100] The mass of the pH-adjusted solution (compositions (1) and (2)) was 27 g, and its composition was 11.6 g of compound e, 10 g of water, 0.09 g of carbon dioxide (the molar ratio relative to compound e was 6 mol%, or 0.3% by mass relative to the mass of the composition), 1.9 g of potassium fluoride, and a small amount of potassium carbonate. The amount of carbon dioxide was determined as follows, using the volume of the reaction vessel (2 L), the amount of carbon dioxide added (8.9 g; 600 mol%), the temperature inside the reaction vessel (25°C), and the pressure inside the reaction vessel (0.25 MPaG). This determination method was similar for other examples.

[0101] In the gas equation of state: PV=nRT, P: 0.25 [MPaG] V: 1.985 [L] (calculated from reaction vessel volume - content volume) Content volume: Volume of solvent (weight / specific gravity used) + Volume of compound e (weight / specific gravity produced: 2.5 g / mL) + Volume of compound b (weight / specific gravity produced: 1.7 g / mL) The specific gravity of the solvent is 1.0 g / mL for water and 0.78 g / mL for methanol. n: The amount of carbon dioxide in the gas phase you want to calculate [mol] R:8.31×10 3 [Pa·L / (mol·K)] T: 298[K](25[℃]) Rearrange the gas equation of state to n=PV / RT, n = (0.25 × 10 6 ×(2.0-(10 / 1+11.6 / 2.5) / 1000)) / (8.31×10 3 ×298) =0.199 The amount of carbon dioxide in the composition (0.201-0.199=0.002 mol (0.09 g)) was calculated by subtracting the amount of carbon dioxide in the gas phase (0.199 mol) from the amount of carbon dioxide added (8.9 g (0.201 mol)).

[0102] Example 2 11.0 g of crude material containing compound a (95% purity) was added to a reaction vessel, followed by 5.5 g of potassium carbonate and 10 g of water, and the mixture was stirred at 0-10°C for 3 hours to obtain a reaction solution. The entire reaction solution was filtered and the pH was confirmed to be 12.0. The filtrate was transferred to a 2.0 L stainless steel pressure vessel, and 21.4 g (1500 mol%) of carbon dioxide was added and stirred for 1 hour to prepare a pH-adjusted solution with a pH of 7.4. The temperature inside the reaction vessel was 25°C and the pressure was 0.60 MPaG. The resulting pH-adjusted solution was concentrated, and NMR analysis of the concentrate revealed that it contained 11.2 g of compound e (96% yield). Furthermore, the interior of the stainless steel reactor was inspected after the reaction, and no corrosion was observed on the vessel surface. The resulting concentrate was added to a reactor and vacuum dried at 140°C for 15 hours (step C). After confirming that it had become a highly concentrated product (water content 100 ppm or less), the temperature was raised to 300°C and further heated at 300°C for 1 hour (step (D)). The product was collected in a -78°C trap. Analysis of the product by NMR and GC revealed that a product containing compound c was obtained in a yield of 78% (compound c:compound d => 99: < 1 (molar ratio)).

[0103] The mass of the pH-adjusting solution (compositions (1) and (2)) was 27 g, and its composition was as follows: 11.2 g of compound e, 10 g of water, 0.24 g of carbon dioxide (the molar ratio relative to compound e was 17 mol%, or 0.9% by mass relative to the mass of the composition), 1.8 g of potassium fluoride, and a small amount of potassium carbonate.

[0104] Example 3 11.2 g (95% purity) of crude material containing compound a was added to a reaction vessel, followed by 5.5 g of potassium carbonate and 10 g of water, and the mixture was stirred at 0 to 10°C for 3 hours to obtain a reaction solution. The entire reaction solution was filtered and the pH was confirmed to be 12.0. The filtrate was transferred to a 2.0 L stainless steel pressure vessel, and 74.2 g (5000 mol%) of carbon dioxide was added and stirred for 1 hour to prepare a pH-adjusted solution with a pH of 6.9. The temperature inside the reaction vessel was 25°C and the pressure was 2.08 MPaG. The resulting pH-adjusted solution was concentrated, and NMR analysis of the concentrate revealed that it contained 11.7 g of compound e (98% yield). Furthermore, the interior of the stainless steel reactor was inspected after the reaction, and no corrosion was observed on the vessel surface. The resulting concentrate was added to a reactor and vacuum dried at 140°C for 15 hours (step C). After confirming that it had become a highly concentrated product (water content 100 ppm or less), the temperature was raised to 300°C and further heated at 300°C for 1 hour (step (D)). The product was collected in a -78°C trap. Analysis of the product by NMR and GC revealed that a product containing compound c was obtained in an 82% yield (compound c:compound d => 99: < 1 (molar ratio)).

[0105] The mass of the pH-adjusting solution (compositions (1) and (2)) was 28 g, and its composition was as follows: 11.7 g of compound e, 10 g of water, 0.96 g of carbon dioxide (the molar ratio relative to compound e was 65 mol%, 3% by mass relative to the mass of the composition), 1.9 g of potassium fluoride, and a small amount of potassium carbonate.

[0106] Example 4 43.0 g (98% purity) of crude material containing compound b was added to a reaction vessel, and 8.1 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 entire reaction solution was filtered, and 1 g of the filtrate was added to 10 g of water. The mixture was vigorously stirred and then allowed to stand. The pH of the aqueous phase was confirmed to be 13.6. The filtrate was transferred to a 10 L stainless steel pressure vessel, and 32.3 g (600 mol%) of carbon dioxide was added and stirred for 1 hour to prepare a pH-adjusted solution with a pH of 7.9. The temperature inside the reaction vessel was 25 °C and the pressure was 0.17 MPaG. The resulting pH-adjusted solution was concentrated, and NMR analysis of the concentrate revealed that it contained 42.3 g of compound e (93% yield). Furthermore, the interior of the stainless steel reactor was inspected after the reaction, and no corrosion was observed on the vessel surface. The resulting concentrate was added to a reactor and vacuum dried at 140°C for 15 hours (step C). After confirming that it had become a highly concentrated product (water content 100 ppm or less), the temperature was raised to 300°C and further heated at 300°C for 1 hour (step (D)). The product was collected in a -78°C trap. Analysis of the product by NMR and GC revealed that a product containing compound c was obtained in a yield of 79% (compound c:compound d => 99: < 1 (molar ratio)).

[0107] The mass of the pH-adjusting solution (compositions (1) and (2)) was 95 g, and its composition was 42.3 g of compound e, 0.76 g of compound b, 45.8 g of methanol, 2.3 g of carbon dioxide gas (the molar ratio relative to compound e was 42 mol%, 2% by mass relative to the mass of the composition), 0.7 g of potassium fluoride, a small amount of potassium carbonate, and a small amount of water.

[0108] Example 5 44.5 g (98% purity) of crude material containing compound b was added to a reaction vessel, and 8.3 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. The entire reaction solution was filtered, and 1 g of the filtrate was added to 10 g of water. The mixture was vigorously stirred and then allowed to stand. The pH of the aqueous phase was confirmed to be 13.8. The filtrate was transferred to a 10 L stainless steel pressure vessel, and 81.5 g (1500 mol%) of carbon dioxide was added and stirred for 1 hour to prepare a pH-adjusted solution with a pH of 7.4. The temperature inside the reaction vessel was 25 °C and the pressure was 0.43 MPaG. The resulting pH-adjusted solution was concentrated, and NMR analysis of the concentrate revealed that it contained 42.7 g of compound e (91% yield). Furthermore, the interior of the stainless steel reactor was inspected after the reaction, and no corrosion was observed on the vessel surface. The resulting concentrate was added to a reactor and vacuum dried at 140°C for 15 hours (step C). After confirming that it had become a highly concentrated product (water content 100 ppm or less), the temperature was raised to 300°C and further heated at 300°C for 1 hour (step (D)). The product was collected in a -78°C trap. Analysis of the product by NMR and GC showed that a product containing compound c was obtained in an 80% yield (compound c:compound d = >99:<1 (molar ratio)).

[0109] The mass of the pH-adjusting solution (compositions (1) and (2)) was 100 g, and its composition was 42.7 g of compound e, 0.65 g of compound b, 45.9 g of methanol, 5.7 g of carbon dioxide gas (the molar ratio relative to compound e was 105 mol%, 6% by mass relative to the mass of the composition), 0.7 g of potassium fluoride, a small amount of potassium carbonate, and a small amount of water.

[0110] Example 6 46.0 g of crude material containing compound b (purity 98%) was added to a reaction vessel, and 8.0 g of potassium hydroxide and 42 g of methanol were further added and stirred at 20°C for 1 hour to obtain a reaction solution. The reaction solution was filtered, and 1 g of the filtrate was added to 10 g of water, vigorously stirred, and then allowed to stand. The pH of the aqueous phase was confirmed to be 13.6. The filtrate was transferred to a 10 L stainless steel pressure vessel, and then 277.4 g (5000 mol%) of carbon dioxide was added and stirred for 1 hour to prepare a pH-adjusted solution with a pH of 6.9. The temperature inside the reaction vessel was 25°C and the pressure was 1.46 MPaG. The resulting pH-adjusted solution was concentrated, and NMR analysis of the concentrate revealed that it contained 43.6 g of compound e (90% yield). After the reaction, the interior of the stainless steel reactor was inspected, and no corrosion was observed on the vessel surface. The resulting concentrate was added to the reactor and vacuum-dried at 140°C for 15 hours (step C). After confirming that a highly concentrated product (water content 100 ppm or less) had been obtained, the temperature was raised to 300°C and further heated at 300°C for 1 hour (step (D)). The product was collected in a -78°C trap. Analysis of the product by NMR and GC revealed that a product containing compound c was obtained in an 84% yield (compound c:compound d = >99:<1 (molar ratio)).

[0111] The mass of the pH-adjusting solution (compositions (1) and (2)) was 115 g, and its composition was 43.6 g of compound e, 0.41 g of compound b, 46.0 g of methanol, 19.4 g of carbon dioxide gas (the molar ratio relative to compound e was 350 mol%, 17% by mass relative to the mass of the composition), 0.72 g of potassium fluoride, a small amount of potassium carbonate, and a small amount of water.

Claims

1. Formula (3): 【Chemistry 1】 [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.] A compound represented by the formula: Formula (4): 【Chemistry 2】 wherein Y is methyl, ethyl, n-propyl, or i-propyl; R １ ~R ４ is the same as above.] At least one compound selected from the group consisting of compounds represented by the formula: carbon dioxide A composition comprising: the content of at least one compound selected from the group consisting of compounds represented by formula (3) and compounds represented by formula (4) is 1 to 90 mass% relative to the mass of the composition; A composition having a carbon dioxide gas content of 0.2 to 30% by mass relative to the mass of the composition, and when 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), the pH of the composition is in the range of 6.0 to 11.0, and when the composition is a non-aqueous solution, the pH of an aqueous solution obtained by adding water to the composition is in the range of 6.0 to 11.

0.

2. 10. The composition of claim 1, further comprising at least one base selected from the group consisting of hydroxides, carbonates, and alkoxides of alkali metals and alkaline earth metals.

3. 3. The composition of claim 2, 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.

4. The composition according to any one of claims 1 to 3, wherein the pH of the aqueous solution is in the range of 6.0 to 10.

0.

5. The composition according to any one of claims 1 to 3, wherein the pH of the aqueous solution is in the range of 6.5 to 10.

0.

6. The base is at least one compound selected from the group consisting of potassium carbonate, sodium carbonate, potassium hydroxide, and sodium hydroxide, The pH of the aqueous solution is in the range of 6.5 to 8.

5. The composition of claim 2.

7. The base is at least one compound selected from the group consisting of potassium carbonate and potassium hydroxide, Y is methyl, M is a potassium atom, the pH of the aqueous solution is in the range of 6.9 to 7.9; The content of the carbon dioxide gas is 0.3 to 17% by mass relative to the mass of the composition. The composition of claim 2.

8. The composition according to claim 1, which is used as a raw material for producing a 1,3-dioxolane compound having a 2-(difluoromethylene) structure.

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