Composition containing fluorine-containing monomer and fluoride ion, method for producing fluorine-containing monomer having reduced fluoride ion content, and method for purifying fluorine-containing monomer

Abstract

To provide, among others: a composition containing a fluorine-containing monomer and fluoride ions, where the amount of fluoride ions mixed in the fluorine-containing monomer is small; a method for producing a fluorine-containing monomer having a further reduced fluoride ion content from a fluorine-containing monomer in which fluoride ions are mixed; and a method for refining a fluorine-containing monomer in which fluoride ions are mixed.SOLUTION: A composition contains a fluorine-containing monomer (M) and fluoride ions, where: the fluoride ion content is 0.01-1,000 mass ppm based on the mass of the composition; and the fluorine-containing monomer (M) is at least one type of monomer selected from the group consisting of compounds represented by formulas (M1), (M2) and (M3). [In the formulas, R1 to R10 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group.]SELECTED DRAWING: None

Description

[Technical field]

[0001] The present disclosure relates to a composition containing a fluorine-containing monomer and a fluoride ion, a method for producing a fluorine-containing monomer having a reduced fluoride ion content, and a method for purifying a fluorine-containing monomer. [Background technology]

[0002] Specific fluorine-containing monomers are used as raw materials for polymerizing fluorine-containing polymers. For example, fluorine-containing polymers obtained by polymerizing perfluoro(2-methylene-4-methyl-1,3-dioxolane), a fluorine-containing monomer having a ring structure, are useful as electronic materials, optical materials, etc.

[0003] Certain fluorine-containing monomers are prone to polymerization during storage. For this reason, techniques for suppressing polymerization have been reported with the aim of stably storing these monomers (Patent Document 1 or 2). Patent Document 1 describes a monomer composition containing a fluorine-containing monomer and 2,6-di-t-butyl-p-cresol or the like. Patent Document 2 describes a method for stabilizing perfluoro(2-methylene-4-methyl-1,3-dioxolane) by making a hydroxyl group-containing fluorine aromatic compound of a specific structure present in a perfluoro(2-methylene-4-methyl-1,3-dioxolane)-containing composition. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 062193 [Patent Document 2] International Publication No. 2020 / 130122 Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have found that a specific fluorine-containing monomer decomposes over time, for example during storage, to generate fluoride ions, which become contaminated by the fluorine-containing monomer. [Means for solving the problem]

[0006] The present inventors have found that if fluoride ions are mixed into a fluorine-containing monomer at a high concentration, the yield decreases when the fluorine-containing polymer is produced by polymerizing the fluorine-containing monomer, the fluoride ions react with the fluorine-containing monomer to decrease the fluorine-containing monomer concentration, and when a polymer obtained by polymerization of a fluorine-containing monomer is heated, a metal fluoride, which is a type of fluoride ion contained in the fluorine-containing monomer, is also contained in the polymer after polymerization, and the metal fluoride acts on polymer terminals such as COOH groups during heating, causing a decarboxylation reaction and resulting in decomposition of the polymer (deterioration in the thermal stability of the polymer). The present inventors have found that fluoride ions contaminated in the fluorine-containing monomer (M) can be simply and effectively reduced by adsorption with activated carbon or washing. The present disclosure aims to provide a composition containing a fluorine-containing monomer and fluoride ions, in which the amount of fluoride ions contaminated in the fluorine-containing monomer is small, to provide a method for producing a fluorine-containing monomer having a reduced fluoride ion content from a fluorine-containing monomer contaminated with fluoride ions, and to provide a method for purifying a fluorine-containing monomer contaminated with fluoride ions, etc.

[0007] The present disclosure encompasses, for example, the following aspects. Section 1. A composition comprising a fluorine-containing monomer (M) and a fluoride ion, The fluoride ion content is 0.01 to 1000 ppm by mass relative to the mass of the composition, The fluorine-containing monomer (M) is Formula (M1) [ka] [In the formula, R 1and R 2 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M2) [ka] [In the formula, R 3 , R 4 , R 5 , and R 6 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M3) [ka] [In the formula, R 7 , R 8 , R 9 , and R 10 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. At least one monomer selected from the group consisting of compounds represented by composition. Section 2. Item 2. The composition according to item 1, wherein the fluorine-containing monomer (M) is at least one compound selected from the group consisting of a compound represented by the following formula (M1-1), a compound represented by the following formula (M2-1), a compound represented by the following formula (M2-2), a compound represented by the following formula (M3-1), and a compound represented by the following formula (M3-2): [ka] Section 3. Item 3. The composition according to item 1 or 2, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): [ka] Section 4. Item 4. The composition according to item 3, further comprising a compound represented by the following formula (C): [ka] Section 5. Item 5. The composition according to item 4, wherein the content of the compound represented by formula (C) is 0.01 to 10% by mass based on the mass of the composition. Section 6. 6. The composition according to any one of items 1 to 5, wherein the fluoride ion content is 50 to 600 ppm by mass based on the mass of the composition. Section 7. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): [ka] Item 2. The composition according to item 1, wherein the fluoride ion content is 50 to 600 ppm by mass based on the mass of the composition. Section 8. A method for producing a fluorine-containing monomer (M) having a reduced fluoride ion content from a fluorine-containing monomer (M) containing fluoride ions, comprising the steps of: a step of treating the fluorine-containing monomer (M) contaminated with fluoride ions with at least one method selected from the group consisting of activated carbon adsorption and washing to reduce the amount of fluoride ions, wherein the fluorine-containing monomer (M) produced has a fluoride ion content of 0.01 to 1000 ppm by mass, The fluorine-containing monomer (M) is Formula (M1) [ka] [In the formula, R 1 and R 2 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M2) [ka] [In the formula, R 3 , R 4 , R 5 , and R 6are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M3) [ka] [In the formula, R 7 , R 8 , R 9 , and R 10 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. At least one monomer selected from the group consisting of compounds represented by Manufacturing method. Section 9. Item 9. The method according to item 8, wherein the method for treating the fluorine-containing monomer (M) contaminated with fluoride ions is activated carbon adsorption. Section 10. Item 10. The production method according to Item 9, wherein the activated carbon adsorption treatment comprises distilling the fluorine-containing monomer (M) contaminated with fluoride ions, and subjecting the distilled fluorine-containing monomer (M) to activated carbon adsorption treatment. Section 11. Item 9. The method according to item 8, wherein the washing is with water or an alkaline aqueous solution. Section 12. The process according to any one of items 8 to 11, wherein the fluorine-containing monomer (M) is at least one compound selected from the group consisting of a compound represented by the following formula (M1-1), a compound represented by the following formula (M2-1), a compound represented by the following formula (M2-2), a compound represented by the following formula (M3-1), and a compound represented by the following formula (M3-2): [ka] Section 13. Item 12. The process according to any one of items 8 to 11, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): [ka] Section 14. Item 14. The method according to any one of Items 8 to 13, wherein the fluoride ion content in the produced fluorine-containing monomer (M) is 50 to 600 ppm by mass. Section 15. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): [ka] A method for treating a fluorine-containing monomer (M) contaminated with fluoride ions is (1) a method for treating the fluorine-containing monomer (M) contaminated with fluoride ions with activated carbon adsorption, (2) a method for distilling the fluorine-containing monomer (M) contaminated with fluoride ions and treating the distilled fluorine-containing monomer (M) with activated carbon adsorption, or (3) a method for washing the fluorine-containing monomer (M) contaminated with fluoride ions with water or an aqueous alkaline solution, Item 9. The production method according to item 8, wherein the fluoride ion content in the produced fluorine-containing monomer (M) is 50 to 600 ppm by mass. Section 16. A method for purifying a fluorine-containing monomer (M) contaminated with fluoride ions, comprising the steps of: The present invention includes a step of treating a fluorine-containing monomer (M) contaminated with fluoride ions with at least one method selected from the group consisting of activated carbon adsorption and washing to reduce the amount of fluoride ions, and the fluorine-containing monomer (M) is Formula (M1) [ka] [In the formula, R 1 and R 2 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M2) [ka] [In the formula, R 3 , R 4 , R 5 , and R 6are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M3) [ka] [In the formula, R 7 , R 8 , R 9 , and R 10 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. At least one monomer selected from the group consisting of compounds represented by Purification method. Section 17. Item 17. The purification method according to Item 16, wherein the purified fluorine-containing monomer (M) has a fluoride ion content of 0.01 to 1000 ppm by mass. Section 18. Item 17. The purification method according to Item 16, wherein the purified fluorine-containing monomer (M) has a fluoride ion content of 50 to 600 ppm by mass. Section 19. Item 17. The purification method according to Item 16, wherein the method for treating the fluorine-containing monomer (M) contaminated with fluoride ions is activated carbon adsorption. Section 20. Item 20. The purification method according to Item 19, wherein the activated carbon adsorption treatment comprises distilling the fluorine-containing monomer (M) contaminated with fluoride ions, and subjecting the distilled fluorine-containing monomer (M) to activated carbon adsorption treatment. Section 21. Item 17. The purification method according to Item 16, wherein the washing is with water or an alkaline aqueous solution. Section 22. 22. The purification method according to any one of items 16 to 21, wherein the fluorine-containing monomer (M) is at least one compound selected from the group consisting of a compound represented by the following formula (M1-1), a compound represented by the following formula (M2-1), a compound represented by the following formula (M2-2), a compound represented by the following formula (M3-1), and a compound represented by the following formula (M3-2): [ka] Section 23. 22. The purification method according to any one of items 16 to 21, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): [ka] Section 24. Item 24. The purification method according to Item 23, wherein the fluorine-containing monomer (M) contaminated with fluoride ions is a fluorine-containing monomer contaminated with fluoride ions and a compound represented by the following formula (C): [ka] Section 25. Item 25. The purification method according to Item 24, wherein the content of the compound represented by formula (C) in the purified fluorinated monomer (M) is 100 to 100,000 ppm by mass. Section 26. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): [ka] The fluorine-containing monomer (M) contaminated with fluoride ions is a fluorine-containing monomer contaminated with fluoride ions and a compound represented by the following formula (C): [ka] A method for treating a fluorine-containing monomer (M) contaminated with fluoride ions is (1) a method for treating the fluorine-containing monomer (M) contaminated with fluoride ions with activated carbon adsorption, (2) a method for distilling the fluorine-containing monomer (M) contaminated with fluoride ions and treating the distilled fluorine-containing monomer (M) with activated carbon adsorption, or (3) a method for washing the fluorine-containing monomer (M) contaminated with fluoride ions with water or an aqueous alkaline solution, the fluoride ion content in the produced fluorine-containing monomer (M) is 50 to 600 ppm by mass, Item 17. The purification method according to Item 16, wherein the content of the compound represented by formula (C) in the purified fluorinated monomer (M) is 100 to 100,000 ppm by mass. Effect of the Invention

[0008] According to the present disclosure, there is provided a method for reducing fluoride ions contaminated in a specific fluorine-containing monomer (a method for purifying a fluorine-containing monomer), and by using this method, it is possible to provide a composition containing a fluorine-containing monomer and fluoride ions, in which the amount of fluoride ions contaminated in the fluorine-containing monomer is small, and it is possible to produce a fluorine-containing monomer having a reduced fluoride ion content from a fluorine-containing monomer contaminated with fluoride ions. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] 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 the 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 exemplary 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.

[0010] term Unless otherwise specified, the symbols and abbreviations 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. As used herein, the phrase "comprising" is intended to encompass the phrases "consisting essentially of" and "consisting of." The steps, treatments, or operations described herein may be carried out at room temperature unless otherwise specified. In this specification, room temperature may mean a temperature in the range of 10 to 40°C. In this specification, the notation "Cn-Cm" (wherein n and m are each a number) indicates that the number of carbon atoms is n or more and m or less, as is commonly understood by those skilled in the art. In this specification, the description of a compound can include all stereoisomers (enantiomers, diastereomers, geometric isomers, etc.) unless otherwise specified by a person skilled in the art.

[0011] In this specification, unless otherwise specified, the term "alkyl group" includes linear, branched, and cyclic alkyl groups. The alkyl group may be a linear or branched alkyl group. The alkyl group can have 1 to 12, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 6, 5, 4, 3, 2, or 1 carbon atom(s), for example. Examples of alkyl groups include straight-chain or branched 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, decyl, undecyl, and dodecyl; and cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.

[0012] In this specification, unless otherwise specified, the term "fluoroalkyl group" includes linear, branched, or cyclic alkyl groups in which at least one hydrogen atom is replaced with a fluorine atom. The fluoroalkyl group may be a linear or branched alkyl group. The fluoroalkyl group can have 1 to 12, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 6, 5, 4, 3, 2, or 1 carbon atom(s). The number of fluorine atoms in the fluoroalkyl group can be 1 or more (for example, 1 to 3, 1 to 5, 1 to 9, 1 to 11, or 1 to the maximum number that can be substituted). The fluoroalkyl group includes a perfluoroalkyl group, which is an alkyl group in which all hydrogen atoms have been replaced with fluorine atoms. 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), butyl having 1 to 9 fluorine atoms (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl), pentyl having 1 to 11 fluorine atoms (e.g., n-pentyl, tert-pentyl, neopentyl, isopentyl, sec-pentyl, 3-pentyl), 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, decyl having 1 to 21 fluorine atoms, undecyl having 1 to 23 fluorine atoms, dodecyl having 1 to 25 fluorine atoms, tridecyl having 1 to 27 fluorine atoms, tetradecyl having 1 to 29 fluorine atoms, and aryl having 1 to 31 fluorines.

[0043] Fluoroalkyl groups include linear or branched C1-C20 fluoroalkyl groups (e.g., C1-C10, C1-C4, C1-C3, etc., preferably C1-C7, more preferably C1-C6 fluoroalkyl groups (preferably perfluoroalkyl groups) such as pentadecyl having a fluorine atom, hexadecyl having 1-33 fluorine atoms, heptadecyl having 1-35 fluorine atoms, octadecyl having 1-37 fluorine atoms, nonadecyl having 1-39 fluorine atoms, and icosyl having 1-41 fluorine atoms; cyclic C3-C10 fluoroalkyl groups (e.g., C3-C6, C4-C6, C3-C5, C5-C6, C4-C8 fluoroalkyl groups) (preferably perfluoroalkyl groups) such as cyclofluoropropyl, cyclofluorobutyl, cyclofluoropentyl, cyclofluorohexyl, cyclofluoroheptyl, cyclofluorooctyl, and fluoroadamantyl. Examples of perfluoroalkyl groups include trifluoromethyl (CF3-), pentafluoroethyl (C2F5-), perfluoropropyl (e.g., CF3CF2CF2-, (CF3)2CF-), perfluorobutyl (e.g., CF3CF2CF2CF2-, (CF3)2CFCF2-, (CF3CF(CF3)CF2-, (CF3)3C-), perfluoropentyl (e.g., CF3CF2CF2CF2CF2-, (CF3)2CFCF2CF2-, CF3CF2CF(CF3)CF2-, CF3CF2CF2CF(CF3)-, CF3C(CF3)2CF2-), and the like. Specific examples of the fluoroalkyl group include the perfluoroalkyl groups exemplified above, a monofluoromethyl group, a difluoromethyl group, a 2,2,2-trifluoroethyl group (CF3CH2-), a tetrafluoropropyl group (e.g., HCF2CF2CH2-), a hexafluoropropyl group (e.g., (CF3)2CH-), and an octafluoropentyl group (e.g., HCF2CF2CF2CF2CH2-).

[0013] In this specification, unless otherwise specified, an "alkoxy group" can be a group represented by RO- [wherein R is an alkyl group]. The alkoxy group includes linear, branched, and cyclic alkoxy groups. The alkoxy group can be a linear or branched alkoxy group. The alkoxy group can have 1 to 12, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 6, 5, 4, 3, 2, or 1 carbon atom. Examples of alkoxy groups can include linear or branched alkoxy groups such as methoxy, ethoxy, propoxy, isopropoxy, butoxy, isobutoxy, sec-butoxy, tert-butoxy, pentyloxy, isopentyloxy, neopentyloxy, hexyloxy, heptyloxy, octyloxy, nonyloxy, and decyloxy, and cyclic alkoxy groups such as cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, and cyclooctyloxy.

[0014] In this specification, unless otherwise specified, a "fluoroalkoxy group" is an alkoxy group in which at least one hydrogen atom is replaced with a fluorine atom. The "fluoroalkoxy group" may be a linear or branched fluoroalkoxy group. The fluoroalkoxy group can have 1 to 12, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 6, 5, 4, 3, 2, or 1 carbon atom(s). The number of fluorine atoms in the fluoroalkoxy group can be 1 or more (for example, 1 to 3, 1 to 5, 1 to 9, 1 to 11, or 1 to the maximum number that can be substituted). Fluoroalkoxy groups include perfluoroalkoxy groups. A perfluoroalkoxy group is an alkoxy group in which all of the hydrogen atoms have been substituted with fluorine atoms. Examples of perfluoroalkoxy groups include trifluoromethyloxy (CF3O-), pentafluoroethyloxy (C2F5O-), perfluoropropyloxy (e.g., CF3CF2CF2O-, (CF3)2CFO-), perfluorobutyloxy (e.g., CF3CF2CF2CF2O-, (CF3)2CFCF2O-, (CF3CF(CF3)CF2O-, (CF3)3CO-), perfluoropentyloxy (e.g., CF3CF2CF2CF2CF2O-, (CF3)2CFCF2CF2O-, CF3CF2CF(CF3)CF2O-, CF3CF2CF2CF(CF3)O-, CF3C(CF3)2CF2O-), and the like. Specific examples of fluoroalkoxy groups include the perfluoroalkoxy groups exemplified above, monofluoromethoxy, difluoromethoxy, 2,2,2-trifluoroethyloxy (CFCHO-), tetrafluoropropyloxy (e.g., HCFCFCHO-), hexafluoropropyloxy (e.g., (CF)CHO-), octafluoropentyloxy (e.g., HCFCFCFCFCHO-), and the like.

[0015] composition One embodiment of the present disclosure is a composition containing a fluorine-containing monomer (M) and fluoride ions. In this composition, the fluoride ion content is low, for example, 0.01 to 1000 ppm by mass relative to the mass of the composition. Therefore, the composition of the present disclosure is useful as a source of the fluorine-containing monomer (M) when polymerizing the fluorine-containing monomer (M) to produce a fluorine-containing polymer. For example, the composition can be subjected to polymerization conditions to produce a fluorine-containing polymer as it is, or after optionally removing or reducing the fluoride ions contained in the composition. In addition, since the composition of the present disclosure has a low fluoride ion content, corrosion of containers, piping, etc. that come into contact with the fluorine-containing monomer (M) can be suppressed.

[0016] Fluorine-containing monomer (M) The fluorine-containing monomer (M) is represented by the formula (M1): [ka] [In the formula, R 1 and R 2 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. (Herein, also referred to as "monomer (M1)") represented by the following formula: Formula (M2) [ka] [In the formula, R 3 , R 4 , R 5 , and R 6 are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. (Herein, also referred to as "monomer (M2)") represented by the following formula: Formula (M3) [ka] [In the formula, R 7 , R 8 , R 9 , and R 10are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. The monomer (M) may be one type alone or two or more types in combination.

[0017] The method for producing the fluorine-containing monomer (M) is known, and in the present disclosure, the fluorine-containing monomer (M) may be produced by applying a known production method. For example, the monomer (M3) can be produced by the methods described in JP-A-2005-002014, WO2020 / 166632, WO2020 / 230822, etc.

[0018] During storage of the fluorine-containing monomer (M), the monomer may decompose over time to generate fluoride ions, and the fluorine-containing monomer may become contaminated with the fluoride ions. In the present disclosure, the fluorine-containing monomer (M) contaminated with fluoride ions is preferably the fluorine-containing monomer (M) generated in this manner. When fluoride ions are generated during the production of the fluorine-containing monomer (M) and a fluorine-containing monomer (M) containing fluoride ions is produced, this may be used as the fluorine-containing monomer (M) contaminated with fluoride ions. The fluorine-containing monomer (M) contaminated with fluoride ions may be one obtained by adding fluoride ions to the fluorine-containing monomer (M).

[0019] Monomer (M1) R 1 and R 2 may each independently be a fluorine atom, a perfluoro C1-C5 alkyl group, or a perfluoro C1-C5 alkoxy group. R 1 and R 2 may each independently be a fluorine atom, a perfluoro C1-C4 alkyl group, or a perfluoro C1-C4 alkoxy group. R 1 and R 2may each independently be a fluorine atom, a perfluoro C1-C3 alkyl group, or a perfluoro C1-C3 alkoxy group. R 1 and R 2 may each independently be a fluorine atom, a perfluoro C1-C2 alkyl group, or a perfluoro C1-C2 alkoxy group. R 1 and R 2 may each independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, or trifluoromethyloxy. R 1 and R 2 may all be fluorine atoms.

[0020] Suitable monomers (M1) include compounds represented by the following formula (M1-1) (also referred to as "monomer (M1-1)" in this specification). [ka]

[0021] Monomer (M2) R 3 , R 4 , R 5 , and R 6 may each independently be a fluorine atom, a perfluoro C1-C5 alkyl group, or a perfluoro C1-C5 alkoxy group. R 3 , R 4 , R 5 , and R 6 may each independently be a fluorine atom, a perfluoro C1-C4 alkyl group, or a perfluoro C1-C4 alkoxy group. R 3 , R 4 , R 5 , and R 6 may each independently be a fluorine atom, a perfluoro C1-C3 alkyl group, or a perfluoro C1-C3 alkoxy group. R 3 , R 4 , R5 , and R 6 may each independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, trifluoromethyloxy, or pentafluoroethyloxy. R 3 , R 4 , R 5 , and R 6 may each independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, or trifluoromethyloxy.

[0022] R 3 , R 4 , R 5 , and R 6 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-C5 alkyl group or a perfluoro C1-C2 alkoxy group. R 3 , R 4 , R 5 , and R 6 At least two groups are fluorine atoms, and the remaining groups, when there are a plurality of the remaining groups, may be independently a perfluoro C1-C5 alkyl group or a perfluoro C1-C2 alkoxy group. In this case, R 3 and R 4 are all fluorine atoms, and R 5 and R 6 are each independently a perfluoro C1-C2 alkyl group or a perfluoro C1-C2 alkoxy group. R 3 , R 4 , R 5 , and R 6 At least three groups are fluorine atoms, and the remaining groups may be perfluoro C1-C5 alkyl groups or perfluoro C1-C2 alkoxy groups. In this case, R 3 , R 5 , and R 6 are all fluorine atoms, and R 4 is suitably a perfluoro C1-C5 alkyl group or a perfluoro C1-C2 alkoxy group. R 3 , R 4 , R 5 , and R 6 At least three groups are fluorine atoms, and the remaining groups may be perfluoro C1-C2 alkoxy groups. In this case, R 3 , R 5 , and R 6 are all fluorine atoms, and R 4 is suitably a perfluoro C1-C2 alkoxy group. R 3 , R 4 , R 5 , and R 6 may all be fluorine atoms.

[0023] Suitable monomers (M2) include compounds represented by the following formula (M2-1) and compounds represented by the following formula (M2-2) (also referred to as "monomer (M2-1)" and "monomer (M2-2)" respectively in this specification). [ka]

[0024] Monomer (M3) R 7 , R 8 , R 9 , and R 10 may each independently be a fluorine atom, a perfluoro C1-C5 alkyl group, or a perfluoro C1-C5 alkoxy group. R 7 , R 8 , R 9 , and R 10 may each independently be a fluorine atom, a perfluoro C1-C4 alkyl group, or a perfluoro C1-C4 alkoxy group. R 7 , R 8 , R 9 , and R 10 may each independently be a fluorine atom, a perfluoro C1-C3 alkyl group, or a perfluoro C1-C3 alkoxy group. R7 , R 8 , R 9 , and R 10 may each independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, trifluoromethyloxy, or pentafluoroethyloxy. R 7 , R 8 , R 9 , and R 10 may each independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, or trifluoromethyloxy.

[0025] R 7 , R 8 , R 9 , and R 10 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-C2 alkoxy group. R 7 , R 8 , R 9 , and R 10 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-C2 alkoxy group. R 7 , R 8 , R 9 , and R 10 At least three groups are fluorine atoms, and the remaining groups may be perfluoro C1-C2 alkyl groups or perfluoro C1-C2 alkoxy groups. R 7 , R 8 , R 9 , and R 10 At least three groups are fluorine atoms, and the remaining groups may be perfluoro C1-C2 alkyl groups. R 7 , R 8 , R 9 , and R 10 may all be fluorine atoms.

[0026] As the monomer (M3), a compound represented by the following formula (M3-1) (perfluoro(2-methylene-4-methyl-1,3-dioxolane); also referred to in this specification as "monomer (M3-1)") or a compound represented by the following formula (M3-2) (perfluoro(2-methylene-1,3-dioxolane); also referred to in this specification as "monomer (M3-2)") is suitable. [ka]

[0027] In the composition of the present disclosure, the content of the fluorine-containing monomer (M) can be, for example, 89.9 to 99.99 mass %, preferably 91 to 99.99 mass %, and more preferably 92 to 99.99 mass %, based on the mass of the composition.

[0028] Fluoride ion The composition of the present disclosure contains fluoride ions in addition to the fluorine-containing monomer (M). In general, the fluorine-containing monomer (M) is decomposed during storage to generate fluoride ions. The fluoride ions cause disadvantages such as reducing the thermal stability of the polymer obtained by polymerizing the fluorine-containing monomer (M), causing corrosion of the production equipment, increasing the cost of waste liquid treatment, or requiring an additional process for removing or reducing the fluoride ions. However, the composition of the present disclosure has a low fluoride ion content. In the composition of the present disclosure, the fluoride ion content can be, for example, 0.01 to 1000 ppm by mass, preferably 0.01 to 800 ppm by mass, more preferably 0.01 to 600 ppm by mass, and even more preferably 50 to 600 ppm by mass, based on the mass of the composition.

[0029] How to determine fluoride ion content The fluoride ion content in the fluorine-containing monomer (M) can be determined as follows. Add 5 mL of pure water to 1 g of monomer (M) and stir at room temperature. Separate the resulting aqueous phase, and add 4 mL of total ionic strength adjustment buffer to 4 mL of the aqueous phase. Measure the fluoride ion concentration of the resulting solution with an ion meter. Taking into account the dilution rate, the concentration of fluoride ions (HF) is determined by multiplying the measured value by 10.

[0030] A compound represented by formula (C) The composition of the present disclosure has formula (C) [ka] (Herein, also referred to as "compound (C)") may be contained.

[0031] In the composition of the present disclosure, the content of compound (C) can be, for example, 0.01 to 10 mass %, preferably 0.01 to 8 mass %, and more preferably 0.01 to 6 mass %, relative to the mass of the composition.

[0032] The composition of the present disclosure may contain other components other than the compound (C) in addition to the fluorine-containing monomer (M) and fluoride ions. Examples of other components include impurities that are mixed in during the production process of the fluorine-containing monomer (M). The content of the other components can be, for example, 0.001 to 8 mass%, 0.001 to 6 mass%, 0.001 to 5 mass%, etc., relative to the mass of the composition.

[0033] The composition of the present disclosure can be obtained, for example, by applying a purification method described below to a fluorine-containing monomer (M) contaminated with fluoride ions. Alternatively, the composition of the present disclosure may be produced by blending fluoride ions with a fluorine-containing monomer (M) not contaminated with fluoride ions.

[0034] Method for purifying fluorine-containing monomer (M) A method for purifying a fluorine-containing monomer (M) contaminated with fluoride ions has not been considered. The purification method of the present disclosure is a method for purifying a fluorine-containing monomer (M) contaminated with fluoride ions, and includes a step of treating the fluorine-containing monomer (M) contaminated with fluoride ions with at least one method selected from the group consisting of activated carbon adsorption and washing to reduce the fluoride ions. By including this step, the purification method of the present disclosure can effectively reduce fluoride ions from the fluorine-containing monomer (M).

[0035] In the process of reducing the amount of fluoride ions in a fluorine-containing monomer (M) contaminated with fluoride ions by activated carbon adsorption treatment (activated carbon adsorption process), for example, the fluorine-containing monomer (M) contaminated with fluoride ions is contacted with activated carbon to adsorb the fluoride ions onto the activated carbon, and the activated carbon is separated to obtain a fluorine-containing monomer (M) with a reduced amount of fluoride ions contaminated therein.

[0036] The fluoride ion content in the fluorine-containing monomer (M) containing fluoride ions may be 0.01 to 1000 ppm by mass, 0.01 to 800 ppm by mass, 0.01 to 600 ppm by mass, or the like.

[0037] The method of activated carbon adsorption treatment is not particularly limited as long as the activated carbon is in contact with the fluorine-containing monomer (M) containing fluoride ions, and the activated carbon may be added to the fluorine-containing monomer (M) containing fluoride ions, or the fluorine-containing monomer (M) containing fluoride ions may be passed through a column packed with activated carbon, etc. After the activated carbon adsorption, the activated carbon can be removed from the fluorine-containing monomer (M) by a known solid-liquid separation method.

[0038] The amount of activated carbon used in the activated carbon adsorption step can be, for example, 1 g or more, 1 to 20 g, and preferably 1 to 10 g, per 100 g of the fluorine-containing monomer (M) containing fluoride ions. The temperature of the activated carbon adsorption treatment is, for example, -40 to 25°C, and preferably -20 to 25°C.

[0039] The fluorine-containing monomer (M) purified by the production method of the present disclosure may contain a compound (C). The content of the compound represented by formula (C) in the purified fluorine-containing monomer (M) may be 100 to 100,000 ppm by mass.

[0040] In the purification method of the present disclosure, a step of distilling the fluorine-containing monomer (M) contaminated with fluoride ions (distillation step) may be provided prior to the activated carbon adsorption step. Distilling the fluorine-containing monomer (M) contaminated with fluoride ions is advantageous in that high-boiling point components such as oligomers of the fluorine-containing monomer (M) can be removed.

[0041] The distillation treatment can be carried out, for example, by applying a known distillation method to the fluorine-containing monomer (M) containing fluoride ions. The distillation temperature is, for example, 30 to 60°C, preferably 30 to 50°C. The distillation pressure is, for example, 50 to 500 hPa, preferably 200 to 500 hPa. The liquid obtained by liquefying the evaporated components produced by distillation by cooling (for example, -78 to -20°C) is subjected to an activated carbon adsorption step.

[0042] In the step of reducing the amount of fluoride ions by washing the fluorine-containing monomer (M) contaminated with fluoride ions (washing step), for example, the fluorine-containing monomer (M) contaminated with fluoride ions is brought into contact with a washing liquid to extract the fluoride ions into an aqueous phase, and the aqueous phase is separated and removed to obtain a non-aqueous phase, thereby obtaining a fluorine-containing monomer (M) contaminated with reduced amounts of fluoride ions. The washing step may be carried out once or may be repeated multiple times, preferably 1 to 3 times.

[0043] The cleaning liquid used in the cleaning step may be water, a KOH aqueous solution, a K2CO3 aqueous solution, a KHCO3 aqueous solution, a NaOH aqueous solution, a NaHCO3 aqueous solution, a Na2CO3 aqueous solution, a CsOH aqueous solution, a Cs2CO3 aqueous solution, a Ca(OH)2 aqueous solution, a Ba(OH)2 aqueous solution, or the like, and is preferably pure water, a KOH aqueous solution, a K2CO3 aqueous solution, or a KHCO3 aqueous solution, and more preferably pure water.

[0044] The amount of the washing liquid used in the washing step can be, for example, 20 g or more, 20 to 500 g, and preferably 50 to 200 g, per 100 g of the fluorine-containing monomer (M) containing fluoride ions. The temperature for the washing treatment is, for example, 5 to 40°C, and preferably 10 to 30°C.

[0045] In the washing step, the non-aqueous phase obtained by the washing treatment may be contacted with a desiccant (molecular sieve, silica gel, calcium chloride, calcium oxide, etc.) to remove the moisture remaining in the non-aqueous phase. The desiccant can be removed from the non-aqueous phase by a known solid-liquid separation method. The amount of the desiccant used may be an appropriate amount, and may be, for example, 1 to 20 g per 100 g of the non-aqueous phase.

[0046] Method for producing fluorine-containing monomer (M) having reduced fluoride ion content The production method of the present disclosure is a method for producing a fluorine-containing monomer (M) having a reduced fluoride ion content (for example, a fluorine-containing monomer (M) having a fluoride ion content of 0.01 to 1000 ppm by mass) from a fluorine-containing monomer (M) contaminated with fluoride ions, and includes a step of treating the fluorine-containing monomer (M) contaminated with fluoride ions with at least one method selected from the group consisting of activated carbon adsorption and washing to reduce the fluoride ions (fluoride ion reduction step).

[0047] The fluoride ion reduction step can be carried out, for example, by applying the above-mentioned method for purifying a fluorine-containing monomer (M) to a fluorine-containing monomer (M) contaminated with fluoride ions. Therefore, the above description regarding the method for purifying a fluorine-containing monomer (M) can be applied to the fluoride ion reduction step to the extent possible.

[0048] The fluorine-containing monomer (M) produced by the production method of the present disclosure has a fluoride ion content of, for example, 0.01 to 1000 ppm by mass, preferably 0.01 to 800 ppm by mass, and more preferably 0.01 to 600 ppm by mass.

[0049] Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. EXAMPLES

[0050] 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.

[0051] The fluorine-containing monomers and the like used in the following examples are as follows. (Fluorine-containing monomer) Perfluoro(2-methylene-4-methyl-1,3-dioxolane (monomer (M3-1)) (Adsorbent; activated carbon) Shirasagi A (Osaka Gas Chemicals Co., Ltd.) (Adsorbent; molecular sieve) Molecular sieves 4A 1 / 16 (Fujifilm Wako Pure Chemical Industries, Ltd.) (Adsorbent: Silica gel) Wakogel (trademark) C-300 (Fujifilm Wako Pure Chemical Industries, Ltd.) (Adsorbent: Alumina) Activated alumina (Fujifilm Wako Pure Chemical Industries, Ltd.)

[0052] (Method for measuring fluoride ion content in fluorine-containing monomer) The fluoride ion content in the fluorine-containing monomer was measured as follows. 5 mL of pure water was added to 1 g of fluorine-containing monomer and stirred at room temperature. The resulting aqueous phase was separated, and 4 mL of total ionic strength adjustment buffer was added to 4 mL of the aqueous phase. The fluoride ion concentration of the prepared solution was measured with an ion meter. Taking into account the dilution rate, the value obtained was 10 times the measured value, which was taken as the fluoride ion (HF) content.

[0053] (Distillation process) The distillation process was carried out as follows. A fluorine-containing monomer was placed in a glass flask, distilled at a temperature of 40° C. and a pressure of 400 hPa, and trapped in acetone at −78° C. cooled with dry ice to obtain a fluorine-containing monomer.

[0054] (Activated carbon adsorption treatment) 0.5 g of activated carbon was added to 10 g of the fluoromonomer, and the mixture was shaken for 10 minutes at 0° C. The fluoromonomer was filtered through a syringe filter to separate and remove the activated carbon, thereby obtaining a purified fluoromonomer.

[0055] (Cleaning process) Pure water or a 5% (w / v) KOH aqueous solution was used as the cleaning solution. 10 g of the fluoromonomer was added with 10 g of the cleaning solution and stirred. The resulting aqueous phase was removed to obtain a non-aqueous phase. 10 g of a new cleaning solution was added to the non-aqueous phase, and a non-aqueous phase was obtained in the same manner. 10 g of a new cleaning solution was added to this non-aqueous phase, and a non-aqueous phase was obtained in the same manner. The cleaning solution was added and stirred (washed) three times. 0.5 g of molecular sieves was added to the obtained non-aqueous phase and stirred to reduce the remaining cleaning solution components. The obtained non-aqueous phase was filtered with a syringe filter to separate and remove the molecular sieves, and a purified fluoromonomer was obtained.

[0056] Production Example 1 (Preparation of Monomer (M3-1)) Monomer (M3-1) was produced by a known method. The fluoride ion content of the resulting monomer (M3-1) was 3000 ppm by mass.

[0057] Example 1 (activated carbon adsorption treatment) The monomer (M3-1) obtained in Production Example 1 was subjected to an activated carbon adsorption treatment. The fluoride ion content of the obtained monomer (M3-1) was 500 ppm by mass. The fluoride ion content was reduced from 3000 ppm by mass to 500 ppm by mass.

[0058] Example 2 (Distillation and Activated Carbon Adsorption Treatment) The monomer (M3-1) obtained in Production Example 1 was distilled and then purified by activated carbon adsorption. The fluoride ion content of the obtained monomer (M3-1) was 80 ppm by mass. The fluoride ion content was reduced from 3000 ppm by mass to 80 ppm by mass.

[0059] Example 3 (Washing with Water) The monomer (M3-1) obtained in Production Example 1 was washed with pure water. The fluoride ion content of the obtained monomer (M3-1) was 340 ppm by mass. The fluoride ion content was reduced from 3000 ppm by mass to 340 ppm by mass.

[0060] Example 4 (Cleaning with 5% KOH aqueous solution) The monomer (M3-1) obtained in Production Example 1 was washed with a 5% KOH aqueous solution. The fluoride ion content of the obtained monomer (M3-1) was 290 ppm by mass. The fluoride ion content was reduced from 3000 ppm by mass to 290 ppm by mass.

[0061] Comparative Examples 1 to 3 (Distillation and Adsorption Treatment) The monomer (M3-1) obtained in Production Example 1 was purified in the same manner as in Example 2, except that the adsorbent was changed from activated carbon to molecular sieves, silica gel, or alumina. The fluoride ion contents of the obtained monomer (M3-1) were 2780 ppm by mass, 1340 ppm by mass, and 1900 ppm by mass, respectively.

[0062] The results of Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1. In Examples 1 to 4, the content of fluoride ions mixed into the fluorine-containing monomer was greatly reduced.

[0063] [Table 1]

Claims

1. A method for producing a fluorine-containing monomer (M) having a reduced fluoride ion content from a fluorine-containing monomer (M) containing fluoride ions, comprising the steps of: the method includes a step of subjecting the fluorine-containing monomer (M) contaminated with fluoride ions to activated carbon adsorption treatment to reduce the amount of fluoride ions, and the fluoride ion content in the produced fluorine-containing monomer (M) is 0.01 to 1000 ppm by mass; The fluorine-containing monomer (M) is Formula (M1) 【Chemistry 1】 [In the formula, R １ and R ２ are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M2) 【Chemistry 2】 [In the formula, R ３ , R ４ , R ５ , and R ６ are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M3) 【Chemistry 3】 [In the formula, R ７ , R ８ , R ９ , and R １０ are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. At least one monomer selected from the group consisting of compounds represented by Manufacturing method.

2. The production method according to claim 1, wherein the activated carbon adsorption treatment comprises distilling the fluorine-containing monomer (M) containing fluoride ions and subjecting the distilled fluorine-containing monomer (M) to activated carbon adsorption treatment.

3. The production method according to claim 1 or 2, wherein the fluorine-containing monomer (M) is at least one compound selected from the group consisting of a compound represented by the following formula (M1-1), a compound represented by the following formula (M2-1), a compound represented by the following formula (M2-2), a compound represented by the following formula (M3-1), and a compound represented by the following formula (M3-2): 【Chemistry 4】

4. The method according to claim 1 or 2, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): 【Chemistry 5】

5. The process according to claim 1 or 2, wherein the fluoride ion content in the produced fluorine-containing monomer (M) is 50 to 600 ppm by mass.

6. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): 【Chemistry 6】 The activated carbon adsorption treatment of the fluorine-containing monomer (M) contaminated with fluoride ions is (1) a treatment of the fluorine-containing monomer (M) contaminated with fluoride ions with activated carbon adsorption, or (2) a treatment of the fluorine-containing monomer (M) contaminated with fluoride ions with activated carbon adsorption, and a treatment of the distilled fluorine-containing monomer (M), The production method according to claim 1, wherein the fluorine-containing monomer (M) produced has a fluoride ion content of 50 to 600 ppm by mass.

7. A method for purifying a fluorine-containing monomer (M) contaminated with fluoride ions, comprising the steps of: The method includes a step of subjecting a fluorine-containing monomer (M) contaminated with fluoride ions to an activated carbon adsorption treatment to reduce the amount of fluoride ions, and the fluorine-containing monomer (M) is Formula (M1) 【Chemistry 7】 [In the formula, R １ and R ２ are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M2) 【Chemistry 8】 [In the formula, R ３ , R ４ , R ５ , and R ６ are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. A compound represented by the formula: Formula (M3) 【Chemistry 9】 [In the formula, R ７ , R ８ , R ９ , and R １０ are each independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. At least one monomer selected from the group consisting of compounds represented by Purification method.

8. The purification method according to claim 7, wherein the purified fluorine-containing monomer (M) has a fluoride ion content of 0.01 to 1000 ppm by mass.

9. The purification method according to claim 7, wherein the purified fluorine-containing monomer (M) has a fluoride ion content of 50 to 600 ppm by mass.

10. 8. The purification method according to claim 7, wherein the activated carbon adsorption treatment comprises distilling the fluorine-containing monomer (M) contaminated with fluoride ions, and subjecting the distilled fluorine-containing monomer (M) to activated carbon adsorption treatment.

11. The purification method according to any one of claims 7 to 10, wherein the fluorine-containing monomer (M) is at least one compound selected from the group consisting of a compound represented by the following formula (M1-1), a compound represented by the following formula (M2-1), a compound represented by the following formula (M2-2), a compound represented by the following formula (M3-1), and a compound represented by the following formula (M3-2): 【Chemistry 10】

12. The purification method according to any one of claims 7 to 10, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): 【Chemistry 11】

13. The purification method according to claim 12, wherein the fluorine-containing monomer (M) contaminated with fluoride ions is a fluorine-containing monomer contaminated with fluoride ions and a compound represented by the following formula (C): 【Chemistry 12】

14. The purification method according to claim 13, wherein the content of the compound represented by formula (C) in the purified fluorinated monomer (M) is 100 to 100,000 ppm by mass.

15. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1): 【Chemistry 13】 The fluorine-containing monomer (M) containing fluoride ions is a fluorine-containing monomer containing fluoride ions and a compound represented by the following formula (C): 【Chemistry 14】 The activated carbon adsorption treatment of the fluorine-containing monomer (M) contaminated with fluoride ions is (1) a treatment of the fluorine-containing monomer (M) contaminated with fluoride ions with activated carbon adsorption, or (2) a treatment of the fluorine-containing monomer (M) contaminated with fluoride ions with activated carbon adsorption, and a treatment of the distilled fluorine-containing monomer (M), the purified fluorine-containing monomer (M) has a fluoride ion content of 50 to 600 ppm by mass, The purification method according to claim 7, wherein the content of the compound represented by formula (C) in the purified fluorinated monomer (M) is 100 to 100,000 ppm by mass.

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