A composition containing a fluorine-containing monomer and fluoride ions, a method for producing a fluorine-containing monomer with reduced fluoride ion content, and a method for purifying a fluorine-containing monomer.

Abstract

To provide a composition containing a fluorine-containing monomer and a fluoride ion, with a small amount of the fluoride ion mixed into the fluorine-containing monomer, to provide a method for producing a fluorine-containing monomer with a further reduced fluoride ion content, from a fluorine-containing monomer mixed with a fluoride ion, and to provide a method of purifying a fluorine-containing monomer mixed with a fluoride ion, and the like.SOLUTION: A composition includes a fluorine-containing monomer and a fluoride ion, where the fluoride ion content is 0.01-1,000 mass ppm relative to the mass of the composition, and the fluorine-containing monomer is at least one monomer selected from the group consisting of compounds expressed by the formula (M1), the formula (M2) and the formula (M3). R1-R10 are each F, a perfluoroalkyl group, or a perfluoroalkoxy group.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to compositions containing fluorine-containing monomers and fluoride ions, methods for producing fluorine-containing monomers with reduced fluoride ion content, and methods for purifying fluorine-containing monomers, etc. [Background technology]

[0002] Certain 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 with a ring structure, are useful as electronic components and optical materials.

[0003] Certain fluorine-containing monomers are prone to polymerization during storage. For this reason, techniques to suppress 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, etc. Patent Document 2 describes a method for stabilizing perfluoro(2-methylene-4-methyl-1,3-dioxolane) by adding a hydroxyl group-containing fluorine aromatic compound of a specific structure to 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 [Overview of the project] [Problems that the invention aims to solve]

[0005] The inventors of the present invention have noticed that certain fluorine-containing monomers decompose over time, for example during storage, to generate fluoride ions, which then contaminate the fluorine-containing monomers. [Means for solving the problem]

[0006] The inventors have learned that when fluoride ions are mixed in with fluorine-containing monomers at a high concentration, the yield decreases when polymerizing the fluorine-containing monomers to produce fluorine-containing polymers; the concentration of fluorine-containing monomers decreases due to the reaction between fluoride ions and fluorine-containing monomers; and when the polymer obtained by polymerizing fluorine-containing monomers is heated, metal fluorides, which are a type of fluoride ion contained in the fluorine-containing monomers, are also contained in the polymer after polymerization. As a result, when heated, the metal fluorides act on polymer ends such as COOH groups, causing a decarboxylation reaction, which leads to the decomposition of the polymer (decreased thermal stability of the polymer). The inventors have found that fluoride ions mixed into a fluorine-containing monomer (M) can be easily and effectively reduced by activated carbon adsorption or washing. This disclosure aims to provide compositions containing fluorine-containing monomers and fluoride ions, which have a low amount of fluoride ions mixed into the fluorine-containing monomer; a method for producing fluorine-containing monomers with a further reduced fluoride ion content from fluorine-containing monomers contaminated with fluoride ions; and a method for purifying fluorine-containing monomers contaminated with fluoride ions.

[0007] This disclosure includes, for example, the following aspects: Section 1. A composition containing a fluorine-containing monomer (M) and fluoride ions, The fluoride ion content is 0.01 to 1000 ppm by mass relative to the composition mass. The aforementioned fluorine-containing monomer (M) is Formula (M1) [ka] [In the formula, R 1and R 2 each independently represent a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group.] a compound represented by Formula (M2)

Chemical Formula

Chemical Formula

Chemical Formula

Chemical Formula

[0008] According to this disclosure, a method for reducing fluoride ions mixed in with a specific fluorine-containing monomer (a method for purifying a fluorine-containing monomer) is provided. By using this method, a composition containing a fluorine-containing monomer and fluoride ions can be provided, which has a low amount of fluoride ions mixed in with the fluorine-containing monomer. Furthermore, a fluorine-containing monomer with an even lower fluoride ion content can be produced from a fluorine-containing monomer that is contaminated with fluoride ions. [Modes for carrying out the invention]

[0009] The foregoing summary of this disclosure is not intended to describe any of the disclosed embodiments or all implementations of this disclosure. The following description in this disclosure provides more specific examples of the embodiments. In several places in this disclosure guidance is provided through examples, and these examples can be used in various combinations. In each case, the exemplary group can function as a non-exclusive and representative group. All publications, patents, and patent applications cited herein are incorporated herein by direct reference.

[0010] term Unless otherwise specified, symbols and abbreviations used herein should be understood in the context of this specification and in the art to which this disclosure belongs as commonly used. In this specification, the phrase "contains" is used to include the phrases "essentially consist of" and "consist of". The processes, treatments, or operations described herein may be carried out at room temperature unless otherwise specified. In this specification, room temperature may mean a temperature within the range of 10 to 40°C. In this specification, the notation "Cn-Cm" (where n and m are numbers, respectively) means, as is usually understood by those skilled in the art, that the number of carbon atoms is n or greater and m or less. In this specification, the notation of compounds may include all stereoisomers (enantiomers, diastereomers, geometric isomers, etc.) unless otherwise specified by those skilled in the art.

[0011] In this specification, unless otherwise specified, "alkyl group" includes linear, branched, and cyclic alkyl groups. An alkyl group may be a linear or branched alkyl group. The number of carbon atoms in the alkyl group can be, for example, 1 to 12, 1 to 6, 1 to 5, 1 to 4, 1 to 3, 6, 5, 4, 3, 2, or 1. Examples of alkyl groups include linear 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, as well as cyclic alkyl groups such as cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, and cyclooctyl.

[0012] In this specification, unless otherwise specified, "fluoroalkyl group" includes linear, branched, or cyclic alkyl groups in which at least one hydrogen atom is substituted with a fluorine atom. A fluoroalkyl group may be a linear or branched alkyl group. The number of carbon atoms in a fluoroalkyl group can be, for example, 1-12, 1-6, 1-5, 1-4, 1-3, 6, 5, 4, 3, 2, or 1. The number of fluorine atoms in a fluoroalkyl group can be one or more (e.g., 1 to 3, 1 to 5, 1 to 9, 1 to 11, or 1 to the maximum number of substituted atoms). Fluoroalkyl groups include perfluoroalkyl groups. Perfluoroalkyl groups are groups in which all hydrogen atoms in the alkyl group are replaced with fluorine atoms. Examples of fluoroalkyl groups include methyl (having 1-3 fluorine atoms), ethyl (having 1-5 fluorine atoms), propyl (e.g., n-propyl, isopropyl) (having 1-7 fluorine atoms), butyl (e.g., n-butyl, isobutyl, sec-butyl, tert-butyl) (having 1-9 fluorine atoms), pentyl (e.g., n-pentyl, tert-pentyl, neopentyl, isopentyl, sec-pentyl, 3-pentyl) (having 1-11 fluorine atoms), hexyl (having 1-13 fluorine atoms), heptyl (having 1-15 fluorine atoms), octyl (having 1-17 fluorine atoms), nonyl (having 1-19 fluorine atoms), and fluoroalkyl groups with 1-21 fluorine atoms. Fluoroalkyl groups such as decyl, 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, pentadecyl having 1 to 31 fluorine atoms, hexadecyl having 1 to 33 fluorine atoms, heptadecyl having 1 to 35 fluorine atoms, octadecyl having 1 to 37 fluorine atoms, nonadecyl having 1 to 39 fluorine atoms, and icosyl having 1 to 41 fluorine atoms, which are linear or branched C1-C20 fluoroalkyl groups (e.g., C1-C10, C1-C4, C1-C3, preferably C1-C7, more preferably C1-C6 fluoroalkyl groups). The group (preferably a perfluoroalkyl group); includes cyclic C3-C10 fluoroalkyl groups such as cyclofluoropropyl, cyclofluorobutyl, cyclofluoropentyl, cyclofluorohexyl, cyclofluoroheptyl, cyclofluorooctyl, and fluoroadamantyl (e.g., C3-C6, C4-C6, C3-C5, C5-C6, and C4-C8 fluoroalkyl groups) (preferably a perfluoroalkyl group). 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-), etc. Examples of fluoroalkyl groups include the perfluoroalkyl groups exemplified above, monofluoromethyl groups, difluoromethyl groups, 2,2,2-trifluoroethyl groups (CF3CH2-), tetrafluoropropyl groups (e.g., HCF2CF2CH2-), hexafluoropropyl groups (e.g., (CF3)2CH-), and octafluoropentyl groups (e.g., HCF2CF2CF2CF2CH2-).

[0013] In this specification, unless otherwise specified, "alkoxy group" may be a group represented by RO-[wherein R is an alkyl group]. Alkoxy groups include linear, branched, and cyclic alkoxy groups. Alkoxy groups may be linear or branched alkoxy groups. The number of carbon atoms in the alkoxy group can be, for example, 1-12, 1-6, 1-5, 1-4, 1-3, 6, 5, 4, 3, 2, or 1. Examples of alkoxy groups 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, as well as 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 substituted with a fluorine atom. A "fluoroalkoxy group" can be a linear or branched fluoroalkoxy group. The number of carbon atoms in the fluoroalkoxy group can be, for example, 1-12, 1-6, 1-5, 1-4, 1-3, 6, 5, 4, 3, 2, or 1. The number of fluorine atoms in a fluoroalkoxy group can be one or more (e.g., 1 to 3, 1 to 5, 1 to 9, 1 to 11, or the maximum number of substituted atoms from 1). Fluoroalkoxy groups include perfluoroalkoxy groups. A perfluoroalkoxy group is a group in which all hydrogen atoms in an alkoxy group are replaced by 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-), etc. Specifically, examples of fluoroalkoxy groups include the perfluoroalkoxy groups exemplified above. Examples include alkoxy groups, monofluoromethoxy, difluoromethoxy, 2,2,2-trifluoroethyloxy (CF3CH2O-), tetrafluoropropyloxy (e.g., HCF2CF2CH2O-), hexafluoropropyloxy (e.g., (CF3)2CHO-), and octafluoropentyloxy (e.g., HCF2CF2CF2CF2CH2O-).

[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. For this reason, the composition of the present disclosure is useful as a source of fluorine-containing monomer (M) when polymerizing the fluorine-containing monomer (M) to produce a fluorine-containing polymer. For example, a fluorine-containing polymer can be produced by subjecting this composition to polymerization conditions, either as is or after optionally removing or reducing the fluoride ions contained in this composition. Furthermore, because the composition of the present disclosure has a low fluoride ion content, corrosion of containers, pipes, 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 given by formula (M1) [ka] [In the formula, R 1 and R 2 Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by (also referred to as "monomer (M1)" in this specification), Formula (M2) [ka] [In the formula, R 3 , R 4 , R 5 , and R 6 Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by (hereinafter also referred to as "monomer (M2)"), and Formula (M3) [ka] [In the formula, R 7 , R 8 , R 9 , and R 10Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. It is at least one monomer selected from the group consisting of compounds represented by (hereinafter also referred to as "monomer (M3)"). Monomer (M) may be a single type or a combination of two or more types.

[0017] Methods for producing fluorine-containing monomers (M) are publicly known, and in this disclosure, fluorine-containing monomers (M) can be produced by applying known production methods. For example, monomer (M3) can be produced by the methods described in Japanese Patent Application Publication No. 2005-002014, WO2020 / 166632, WO2020 / 230822, etc.

[0018] During storage, the fluorine-containing monomer (M) may decompose over time to generate fluoride ions, which can contaminate the fluorine-containing monomer. In this disclosure, the fluorine-containing monomer (M) contaminated with fluoride ions is preferably the fluorine-containing monomer (M) produced in this manner. As the fluorine-containing monomer (M) contaminated with fluoride ions, if 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 can also be used. The fluorine-containing monomer (M) contaminated with fluoride ions may also be obtained by adding fluoride ions to the fluorine-containing monomer (M).

[0019] Monomer (M1) R 1 and R 2 Each of these may independently be a fluorine atom, a perfluoroC1-C5 alkyl group, or a perfluoroC1-C5 alkoxy group. R 1 and R 2 Each of these may independently be a fluorine atom, a perfluoroC1-C4 alkyl group, or a perfluoroC1-C4 alkoxy group. R 1 and R 2Each of these may independently be a fluorine atom, a perfluoroC1-C3 alkyl group, or a perfluoroC1-C3 alkoxy group. R 1 and R 2 Each of these may independently be a fluorine atom, a perfluoroC1-C2 alkyl group, or a perfluoroC1-C2 alkoxy group. R 1 and R 2 Each of these may independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, or trifluoromethyloxy. R 1 and R 2 These can all be fluorine atoms.

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

[0021] Monomer (M2) R 3 , R 4 , R 5 , and R 6 Each of these may independently be a fluorine atom, a perfluoroC1-C5 alkyl group, or a perfluoroC1-C5 alkoxy group. R 3 , R 4 , R 5 , and R 6 Each of these may independently be a fluorine atom, a perfluoroC1-C4 alkyl group, or a perfluoroC1-C4 alkoxy group. R 3 , R 4 , R 5 , and R 6 Each of these may independently be a fluorine atom, a perfluoroC1-C3 alkyl group, or a perfluoroC1-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 when there are a plurality of remaining groups, the remaining groups may each 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 when there are a plurality of remaining groups, the remaining groups may each independently be a perfluoro C1-C5 alkyl group or a perfluoro C1-C2 alkoxy group. In this case, R 3 and R 4 are both fluorine atoms, and R 5 and R 6 are preferably 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 group may be a perfluoro C1-C5 alkyl group or a perfluoro C1-C2 alkoxy group. In this case, R 3 , R 5 , and R 6 are all fluorine atoms, and R 4 is preferably 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 preferably 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 a compound represented by the following formula (M2-1) and a compound represented by formula (M2-2) (each also referred to as "monomer (M2-1)" and "monomer (M2-2)" herein, respectively).

Chemical Formula

[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 Each of these may independently be a fluorine atom, trifluoromethyl, pentafluoroethyl, trifluoromethyloxy, or pentafluoroethyloxy. R 7 , R 8 , R 9 , and R 10 Each of these may 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, if there are multiple such remaining groups, may independently be perfluoroC1-C2 alkyl groups or perfluoroC1-C2 alkoxy groups. R 7 , R 8 , R 9 , and R 10 At least two of the groups are fluorine atoms, and the remaining groups, if there are multiple such remaining groups, may independently be perfluoroC1-C2 alkyl groups or perfluoroC1-C2 alkoxy groups. R 7 , R 8 , R 9 , and R 10 The group comprises at least three fluorine atoms, and the remaining groups may be perfluoroC1-C2 alkyl groups or perfluoroC1-C2 alkoxy groups. R 7 , R 8 , R 9 , and R 10 This group may have at least three fluorine atoms, and the remaining groups may be perfluoroC1-C2 alkyl groups. R 7 , R 8 , R 9 , and R 10 These can 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 herein as "monomer (M3-1)") or a compound represented by the following formula (M3-2) (perfluoro(2-methylene-1,3-dioxolane); also referred to herein as "monomer (M3-2)") is preferred. [ka]

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

[0028] Fluoride ions The compositions of this disclosure contain fluoride ions in addition to a fluorine-containing monomer (M). Generally, fluorine-containing monomers (M) decompose during storage to generate fluoride ions. Fluoride ions have disadvantages such as reducing the thermal stability of polymers polymerized from fluorine-containing monomers (M), causing corrosion of manufacturing equipment, increasing wastewater treatment costs, or requiring further processes for fluoride ion removal or reduction. However, the compositions of this disclosure have a low fluoride ion content. In the compositions of this 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, relative to the mass of the composition.

[0029] Method for determining fluoride ion content The fluoride ion content in a 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 ion strength adjustment buffer to 4 mL of the aqueous phase. Measure the fluoride ion concentration of the prepared solution using an ion meter. Considering the dilution ratio, take 10 times the measured value as the fluoride ion (HF) concentration.

[0030] Compound represented by formula (C) The compositions disclosed herein are of formula (C) [ka] The material may contain a compound represented by (hereinafter also referred to as "compound (C)") as shown herein.

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

[0032] The compositions of this disclosure may contain other components besides compound (C) in addition to the fluorine-containing monomer (M) and fluoride ions. Examples of other components include impurities introduced during the manufacturing process of the fluorine-containing monomer (M). The content of the other components can be, for example, 0.001 to 8% by mass, 0.001 to 6% by mass, 0.001 to 5% by mass, etc., relative to the mass of the composition.

[0033] The compositions of this disclosure can be obtained, for example, by applying the purification method described later to a fluorine-containing monomer (M) contaminated with fluoride ions. Alternatively, the compositions of this disclosure may be produced by compounding fluoride ions into a fluorine-containing monomer (M) that is not contaminated with fluoride ions.

[0034] Method for purifying fluorine-containing monomers (M) No method had been investigated for purifying fluorine-containing monomers (M) contaminated with fluoride ions. The purification method of this disclosure is a method for purifying fluorine-containing monomers (M) contaminated with fluoride ions, and includes a step of reducing fluoride ions by treating the fluorine-containing monomers (M) contaminated with fluoride ions with at least one method selected from the group consisting of activated carbon adsorption and washing. By including this step, the purification method of this disclosure can effectively reduce fluoride ions from fluorine-containing monomers (M).

[0035] In the process of reducing 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 brought into contact with activated carbon to adsorb the fluoride ions onto the activated carbon, and the activated carbon is separated, thereby obtaining a fluorine-containing monomer (M) with a reduced amount of fluoride ions.

[0036] The fluoride ion content in a fluorine-containing monomer (M) contaminated with fluoride ions can be 0.01 to 1000 ppm by mass, 0.01 to 800 ppm by mass, 0.01 to 600 ppm by mass, etc.

[0037] The method of activated carbon adsorption treatment is not particularly limited as long as the activated carbon comes into contact with the fluorine-containing monomer (M) contaminated with fluoride ions. Activated carbon may be added to the fluorine-containing monomer (M) contaminated with fluoride ions, or the fluorine-containing monomer (M) contaminated with fluoride ions may be passed through a column packed with activated carbon. After 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 process can be, for example, 1g or more, and preferably 1 to 10g, per 100g of fluorine-containing monomer (M) mixed with fluoride ions. The temperature for the activated carbon adsorption treatment is, for example, -40 to 25°C, preferably -20 to 25°C.

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

[0040] In the purification method of this disclosure, a step of distilling the fluorine-containing monomer (M) contaminated with fluoride ions (distillation step) may be provided before the activated carbon adsorption step. This is advantageous because distilling the fluorine-containing monomer (M) contaminated with fluoride ions can remove high-boiling-point components such as oligomers of the fluorine-containing monomer (M).

[0041] Distillation methods are known, for example, for fluorine-containing monomers (M) contaminated with fluoride ions. This can be carried out by applying the distillation method described above. 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 evaporated components produced by distillation are liquefied by cooling (for example, -78 to -20°C), and the resulting liquid is subjected to the activated carbon adsorption process.

[0042] In the washing process, which reduces the amount of fluoride ions in a fluorine-containing monomer (M) contaminated with fluoride ions, for example, the fluorine-containing monomer (M) contaminated with fluoride ions is brought into contact with a washing solution to extract the fluoride ions into the aqueous phase, and the aqueous phase is separated and removed to obtain a non-aqueous phase, thereby obtaining a fluorine-containing monomer (M) with a reduced amount of fluoride ions. The washing process may be performed once or repeated multiple times, preferably 1 to 3 times.

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

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

[0045] In the washing process, a desiccant (such as molecular sieves, silica gel, calcium chloride, or calcium oxide) may be brought into contact with the non-aqueous phase obtained from the washing treatment to remove any remaining moisture in the non-aqueous phase. The desiccant can be removed from the non-aqueous phase by known solid-liquid separation methods. The amount of desiccant used can be appropriate, but for example, it may be 1 to 20 g per 100 g of non-aqueous phase.

[0046] Method for producing a fluorine-containing monomer (M) with a reduced fluoride ion content. The present disclosure provides a method for producing a fluorine-containing monomer (M) with a further reduced fluoride ion content (for example, a fluorine-containing monomer (M) with 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 reducing the fluoride ions by 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 (fluoride ion reduction step).

[0047] The fluoride ion reduction process can be carried out, for example, by applying the above-described purification method for fluoride-containing monomers (M) to fluoride-containing monomers (M) contaminated with fluoride ions. Therefore, the above-described method for purifying fluoride-containing monomers (M) can be applied to the fluoride ion reduction process to the extent possible.

[0048] The fluoride ion content in the fluorine-containing monomer (M) produced by the manufacturing method of this disclosure is, 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 embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. [Examples]

[0050] The following describes in more detail one embodiment of this disclosure by reference to examples, but this disclosure is not limited to the above. It is not limited to that.

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

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

[0053] (Distillation process) The distillation process was carried out as follows: Fluorine-containing monomers were placed in a glass flask, distilled at 40°C and 400 hPa, and then trapped with acetone at -78°C cooled with dry ice to obtain the fluorine-containing monomers.

[0054] (Activated carbon adsorption treatment) 10 g of fluorine-containing monomer was mixed with 0.5 g of activated carbon and shaken at 0°C for 10 minutes. The activated carbon was separated and removed by filtering the fluorine-containing monomer through a syringe filter to obtain purified fluorine-containing monomer.

[0055] (Cleaning process) For the washing solution, pure water or a 5% (w / v) KOH aqueous solution was used. 10g of fluorine-containing monomer 10 g of washing solution was added to the mixture and stirred. The resulting aqueous phase was removed to obtain a non-aqueous phase. 10 g of fresh washing solution was added to the non-aqueous phase and a non-aqueous phase was obtained in the same manner. 10 g of fresh washing solution was added to this non-aqueous phase and a non-aqueous phase was obtained in the same manner. The mixture was stirred (washed) three times in total. 0.5 g of molecular sieve was added to the obtained non-aqueous phase and stirred to reduce the remaining washing solution components. The molecular sieve was separated and removed by filtering the obtained non-aqueous phase through a syringe filter to obtain a purified fluorine-containing monomer.

[0056] Manufacturing Example 1 (Preparation of monomer (M3-1)) Monomer (M3-1) was prepared by a known method. The fluoride ion content of the obtained 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 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 subjected to distillation 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 treatment 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 (Washing treatment 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 1-3 (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 content of the obtained monomer (M3-1) was 2780 ppm by mass, 1340 ppm by mass, and 1900 ppm by mass, respectively.

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

[0063] [Table 1]

Claims

1. A composition containing a fluorine-containing monomer (M) and fluoride ions, The content of fluorine-containing monomers (M) is 89.9 to 99.99% by mass relative to the mass of the composition. The fluoride ion content is 0.01 to 1000 ppm by mass relative to the composition mass. The fluorine-containing monomer (M) is Formula (M1) 【Chemistry 1】 [In the formula, R １ and R ２ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by, Formula (M2) 【Chemistry 2】 [In the formula, R ３ , R ４ , R ５ , and R ６ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by, and Formula (M3) 【Transformation 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.]] It is at least one monomer selected from the group consisting of compounds represented by composition.

2. The composition according to claim 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). 【Chemistry 4】

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

4. The composition according to claim 3, further comprising a compound represented by the following formula (C). 【Transformation 6】

5. The composition according to claim 4, wherein the content of the compound represented by formula (C) is 0.01 to 10% by mass relative to the mass of the composition.

6. The composition according to claim 1, wherein the fluoride ion content is 50 to 600 ppm by mass relative to the mass of the composition.

7. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1), 【Transformation 7】 The composition according to claim 1, wherein the fluoride ion content is 50 to 600 ppm by mass relative to the mass of the composition.

8. A method for producing a fluorine-containing monomer (M) with a further reduced fluoride ion content from a fluorine-containing monomer (M) contaminated with fluoride ions, The process includes a step of reducing the amount of fluoride ions in a fluorine-containing monomer (M) contaminated with fluoride ions by washing it with water or an alkaline aqueous solution, wherein 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) 【Transformation 8】 [In the formula, R １ and R ２ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by, Formula (M2) 【Chemistry 9】 [In the formula, R ３ , R ４ , R ５ , and R ６ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by, and Formula (M3) 【Chemistry 10】 [In the formula, R ７ , R ８ , R ９ , and R １０ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. It is at least one monomer selected from the group consisting of compounds represented by Manufacturing method.

9. The aforementioned washing treatment involves water, KOH aqueous solution, K ２ CO ３ Aqueous solution, or KHCO ３ The manufacturing method according to claim 8, wherein the washing treatment is performed with an aqueous solution.

10. The manufacturing method according to claim 8, wherein the washing treatment is a washing treatment with water or an aqueous KOH solution.

11. The method for producing the product according to claim 8 or 9, 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 11】

12. The production method according to claim 8 or 9, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1). 【Chemistry 12】

13. The manufacturing method according to claim 8 or 9, wherein the fluoride ion content in the fluorine-containing monomer (M) produced is 50 to 600 ppm by mass.

14. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1), 【Chemistry 13】 The manufacturing method according to claim 8, wherein the fluoride ion content in the fluorine-containing monomer (M) produced is 50 to 600 ppm by mass.

15. A method for purifying a fluorine-containing monomer (M) contaminated with fluoride ions, The process includes a step of reducing the amount of fluoride ions in a fluorine-containing monomer (M) contaminated with fluoride ions by washing it with water or an alkaline aqueous solution, wherein the fluorine-containing monomer (M) is Formula (M1) 【Chemistry 14】 [In the formula, R １ and R ２ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by, Formula (M2) 【Chemistry 15】 [In the formula, R ３ , R ４ , R ５ , and R ６ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. Compounds represented by, and Formula (M3) 【Chemistry 16】 [In the formula, R ７ , R ８ , R ９ , and R １０ Each of these is independently a fluorine atom, a perfluoroalkyl group, or a perfluoroalkoxy group. It is at least one monomer selected from the group consisting of compounds represented by Purification method.

16. The purification method according to claim 15, wherein the fluoride ion content in the purified fluorine-containing monomer (M) is 0.01 to 1000 ppm by mass.

17. The purification method according to claim 15, wherein the fluoride ion content in the purified fluorine-containing monomer (M) is 50 to 600 ppm by mass.

18. The aforementioned washing treatment involves water, KOH aqueous solution, K ２ CO ３ Aqueous solution, or KHCO ３ The purification method according to claim 15 or 16, wherein the washing is performed with an aqueous solution.

19. The purification method according to claim 15 or 16, wherein the washing treatment is a washing treatment with water or an aqueous KOH solution.

20. The purification method according to claim 15 or 16, 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 17】

21. The purification method according to claim 15 or 16, wherein the fluorine-containing monomer (M) is a compound represented by the following formula (M3-1). [Chemistry 18]

22. The purification method according to claim 21, 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 19】

23. The purification method according to claim 22, wherein the content of the compound represented by formula (C) in the purified fluorine-containing monomer (M) is 100 to 100,000 ppm by mass.

24. The fluorine-containing monomer (M) is a compound represented by the following formula (M3-1), 【Chemistry 20】 A 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 21】 The fluoride ion content in the purified fluorine-containing monomer (M) is 50 to 600 ppm by mass. The purification method according to claim 15, wherein the content of the compound represented by formula (C) in the purified fluorine-containing monomer (M) is 100 to 100,000 ppm by mass.

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