Method for stabilizing perfluorodioxolane compound, composition containing perfluorodioxolane compound, and method for producing perfluorodioxolane compound polymer

Abstract

Provided is a method for stabilizing a perfluorodioxolane compound, said method including causing a quinone compound to be present within a composition that includes the perfluorodioxolane compound, wherein the perfluorodioxolane compound is at least one type of compound selected from the group consisting of a perfluorodioxolane compound represented by general formula (1) and a perfluorodioxolane compound represented by general formula (2), and the quinone compound is at least one type of compound selected from the group consisting of a quinone compound represented by general formula (3) and a quinone compound represented by general formula (4). (In this formula, Rf1 and Rf2 each independently represent a fluorine atom or a C1-6 perfluoroalkyl group, and may have an ether bond within an arbitrary carbon-carbon bond of said perfluoroalkyl group. Additionally, Rf1 and Rf2 may be bonded to one another to form a ring.) (In this formula, Rf3 and Rf4 each independently represent a fluorine atom or a C1-6 perfluoroalkyl group, and may have an ether bond within an arbitrary carbon-carbon bond of said perfluoroalkyl group.) (In this formula, R1-R4 each independently represent a hydrogen atom, a fluorine atom, or a chlorine atom.) (In this formula, R5-R10 each independently represent a hydrogen atom, a fluorine atom, or a chlorine atom.)

Description

[Technical field]

[0001] The present invention relates to a method for stabilizing a perfluorodioxolane compound, a perfluorodioxolane compound-containing composition, and a method for producing a perfluorodioxolane compound polymer. [Background technology]

[0002] As a perfluorodioxolane compound, for example, perfluoro(2-methylene-4-methyl-1,3-dioxolane) can undergo radical polymerization in the presence of an initiator, and is used as a synthetic raw material for poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)]. Poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)] is promising as a resin for gas separation membranes, a transparent resin for optical fibers, and the like. In detail, poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)] is a transparent polymer having an amorphous structure and has a high glass transition temperature (133 to 136°C), and is therefore expected to be a next-generation resin for optical fibers and a resin for gas separation membranes (Non-Patent Document 1).

[0003] Meanwhile, in the past, for the purpose of stabilizing fluorine-containing monomers during storage, the addition of polymerization inhibitors such as the terpene compounds described in Patent Document 1 and the phenolic compounds described in Patent Document 2 has been considered. Patent Document 3 also discloses a 6-membered unsaturated hydrocarbon having a t-butyl group or the like as a polymerization inhibitor for a ring structure monomer containing perfluoro(2-methylene-4-methyl-1,3-dioxolane).

[0004] Patent Document 1: U.S. Patent No. 2,737,533 Patent Document 2: Japanese Patent Publication No. 50-7046 Patent document 3: WO2018 / 062193 publication

[0005] Non-patent document 1: Y. Okamoto, et.al., Polym.Adv.Technol. 2016, 27 33-41

Summary of the Invention

[0006] In the above applications where the application of poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)] is expected, it is necessary to control the molecular weight and polymer properties according to the purpose. For this purpose, it is desirable to suppress the progress of the polymerization reaction during the storage of the perfluorodioxolane compound, which is the raw material monomer, and use it in the polymerization reaction while maintaining the quality of the monomer. Furthermore, in optical applications, a high level of quality stability such as prevention of coloring is also required.

[0007] In addition, the polymerization inhibitor described in Patent Document 3 needs to be purified by distillation to remove the unsaturated hydrocarbon used as the polymerization inhibitor each time the polymerization reaction of the cyclic structure monomer is actually carried out (see paragraph 0034 of Patent Document 3, etc.). The operation is complicated, and dedicated equipment for polymerization is required.

[0008] In view of the above, one aspect of the present invention provides a new means for stabilizing perfluorodioxolane compounds. Specifically, one aspect of the present invention is less likely to cause quality changes such as polymerization reactions and coloring during storage, and the compound added for stabilization can be easily separated, or the polymerization reaction of the perfluorodioxolane compound can proceed without separation. A method for stabilizing a perfluorodioxolane compound is provided.

[0009] As a result of intensive studies on the method for stabilizing perfluorodioxolane, the present inventors have newly found that by allowing a quinone compound having a specific structure to be present in a composition containing a perfluorodioxolane compound, it is possible to make it less likely to cause quality changes such as polymerization reactions and coloring during storage. Furthermore, since the above quinone compound can be excellently stabilized even when present in a very small amount, it has also been found that the composition containing this quinone compound can be subjected to a polymerization reaction without easily separating the quinone compound or without the need for separation.

[0010] One aspect of the present invention is as follows.

[0011] [1] comprising the presence of a quinone compound in a composition containing a perfluorodioxolane compound, wherein the perfluorodioxolane compound is represented by the following general formula (1):

Chemical formula

Chemical formula

Chemical formula

Chemical formula

[10] The quinone compound-containing composition according to [9], which contains the quinone compound in a weight ratio of 0.1 to 500 ppm with respect to the perfluorodioxolane compound.

[11] R in the general formula (3) 1 ~R 4 The perfluorodioxolane compound-containing composition according to [9] or

[10] , wherein at least one of them is a fluorine atom.

[12] The quinone compound-containing composition according to any one of [9] to

[11] , wherein the quinone compound contains the quinone compound represented by the general formula (3).

[13] The quinone compound-containing composition according to any one of [9] to

[12] , wherein the quinone compound contains perfluoro-p-benzoquinone.

[14] R in the general formula (4) 5 ~R 10 The perfluorodioxolane compound-containing composition according to any one of [9] to

[13] , wherein at least one of them is a fluorine atom.

[15] A method for producing a perfluorodioxolane compound polymer, which comprises adding a polymerization initiator to the perfluorodioxolane compound-containing composition according to any one of [9] to

[14] and polymerizing the perfluorodioxolane compound.

[16] The perfluorodioxolane compound-containing composition, wherein the content of the perfluorodioxolane compound polymer after storage under nitrogen for one week or more is 1.0% by weight or less.

[17] A method for producing a perfluorodioxolane compound polymer, which comprises adding a polymerization initiator to the perfluorodioxolane compound-containing composition according to

[16] and polymerizing the perfluorodioxolane compound.

[0012] According to one aspect of the present invention, a perfluorodioxolane compound-containing composition that is less likely to cause quality changes such as polymerization reaction and coloring during storage can be provided.

Mode for Carrying Out the Invention

[0013] [Stabilization Method] One aspect of the present invention relates to a method for stabilizing a perfluorodioxolane compound, which includes causing a quinone compound to be present in a composition containing the perfluorodioxolane compound. The perfluorodioxolane compound is one or more selected from the group consisting of the perfluorodioxolane compound represented by the general formula (1) and the perfluorodioxolane compound represented by the general formula (2), and the quinone compound is one or more selected from the group consisting of the quinone compound represented by the general formula (3) and the quinone compound represented by the general formula (4).

[0014] According to the above stabilization method, by causing a specific quinone compound to be present in the perfluorodioxolane compound, the progress of the polymerization reaction of the perfluorodioxolane compound during storage can be suppressed, and coloring can also be suppressed. The perfluorodioxolane compound may be a single component or a composition of two or more perfluorodioxolane compounds. Also, the specific quinone compound may be a single component or a composition of two or more quinone compounds. More specifically, according to the above stabilization method, by causing one or more selected from the group consisting of the quinone compound represented by the general formula (3) and the quinone compound represented by the general formula (4) to be present in the composition containing the perfluorodioxolane compound, the progress of the polymerization reaction of the perfluorodioxolane compound during storage can be suppressed, and coloring can also be suppressed.

[0015] [Perfluorodioxolane Compound] The perfluorodioxolane compound to be stabilized by the above stabilization method is selected from the group consisting of a perfluorodioxolane compound represented by the general formula (1) and a perfluorodioxolane compound represented by the general formula (2). Hereinafter, the perfluorodioxolane compound represented by the general formula (1) is referred to as "perfluorodioxolane compound A", and the perfluorodioxolane compound represented by the general formula (2) is referred to as "perfluorodioxolane compound B".

[0016] (Perfluorodioxolane compound A) The perfluorodioxolane compound A is represented by the general formula (1). In the general formula (1), Rf 1 , Rf 2 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and an ether bond may be present between any carbon-carbon bonds of the perfluoroalkyl group. Also, Rf 1 , Rf 2 may be bonded to each other to form a ring.

[0017] Rf 1 , Rf 2 The perfluoroalkyl group having 1 to 6 carbon atoms, which is one form of, may be linear or branched. Specific examples of such perfluoroalkyl groups include a trifluoromethyl group, a pentafluoroethyl group, a heptafluoro-n-propyl group, a heptafluoro-isopropyl group, a nonafluoro-n-butyl group, a nonafluoro-isobutyl group, a nonafluoro-sec-butyl group, a nonafluoro-tert-butyl group, a perfluoro(methoxymethyl) group, a perfluoro(ethoxymethyl) group, and the like. Among these, from the viewpoint of ease of production, a trifluoromethyl group, a pentafluoroethyl group, and a perfluoro(methoxymethyl) group are preferred, and a trifluoromethyl group is more preferred.

[0018] As Rf 1 , Rf 2 in the general formula (1), a fluorine atom and a trifluoromethyl group are particularly preferred. In one form, Rf 1 , Rf2 is preferably a fluorine atom in each case. In another embodiment, Rf 1 , Rf 2 is preferably a trifluoromethyl group in each case.

[0019] Examples of the perfluorodioxolane compound A include the following exemplified compounds. However, the present invention is not limited thereto.

[0020]

Chemical formula

[0021] The above-exemplified compound 1-2 is perfluoro(2-methylene-4-methyl-1,3-dioxolane). In the present invention, it is particularly preferable that the stabilization target is perfluoro(2-methylene-4-methyl-1,3-dioxolane).

[0022] The perfluorodioxolane compound A can be obtained by a method known in the literature, for example, the method described in Macromolecules 2005, 38, 4237-4245 and Patent No. 4776536.

[0023] (Perfluorodioxolane compound B) The perfluorodioxolane compound B is represented by the general formula (2). In the general formula (2), Rf 3 , Rf 4 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and an ether bond may be present between any carbon-carbon bonds of the perfluoroalkyl group.

[0024] Rf 3 , Rf 4In one form, the perfluoroalkyl group having 1 to 6 carbon atoms may be linear or branched. Specific examples of such perfluoroalkyl groups include a trifluoromethyl group, a pentafluoroethyl group, a heptafluoro-n-propyl group, a heptafluoro-isopropyl group, a nonafluoro-n-butyl group, a nonafluoro-isobutyl group, a nonafluoro-sec-butyl group, a nonafluoro-tert-butyl group, a perfluoro(methoxymethyl) group, a perfluoro(ethoxymethyl) group, and the like. Among these, from the viewpoint of ease of production, a trifluoromethyl group, a pentafluoroethyl group, and a perfluoro(methoxymethyl) group are preferred, and a trifluoromethyl group is more preferred.

[0025] Rf in General Formula (2) 3 , Rf 4 is particularly preferably a fluorine atom or a trifluoromethyl group. In one form, it is preferred that both Rf 3 , Rf 4 are fluorine atoms. In another form, it is preferred that both Rf 3 , Rf 4 are trifluoromethyl groups.

[0026] The perfluorodioxolane compound B can be obtained by a method known from the literature, for example, the method described in Macromolecules 1993, 26, 5829 - 5834.

[0027] In the above stabilization method, a quinone compound is present in the composition containing the perfluorodioxolane compound. The perfluorodioxolane compound contained in such a composition can be only one kind in one form, and can be two or more kinds in another form. For example, the above composition can contain only one or two or more of perfluorodioxolane compound A, can contain only one or two or more of perfluorodioxolane compound B, or can contain one or two or more of perfluorodioxolane compound A and one or two or more of perfluorodioxolane compound B. Two or more perfluorodioxolane compounds can be contained in the above composition in an arbitrary mixing ratio.

[0028] <Quinone compound> Next, the quinone compound will be described.

[0029] The quinone compound present in the composition containing the perfluorodioxolane compound is selected from the group consisting of the quinone compound represented by the general formula (3) and the quinone compound represented by the general formula (4). Hereinafter, the quinone compound represented by the general formula (3) is referred to as "quinone compound a", and the quinone compound represented by the general formula (4) is referred to as "quinone compound b".

[0030] (Quinone compound a) Quinone compound a is represented by the general formula (3). In the general formula (3), R 1 ~R 4 each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.

[0031] R 1 ~R 4 Of these, it is preferable that at least one is a fluorine atom or a chlorine atom, and more preferably at least one is a fluorine atom. In one form, the quinone compound a represented by the general formula (3) is a perfluoro compound, that is, it is preferable that R 1 ~R 4 in the general formula (3) are all fluorine atoms.

[0032] Examples of the quinone compound a include the following exemplified compounds. However, the present invention is not limited thereto.

[0033]

Chemical formula

[0034] In general formula (3), it is more preferable that all of R 1 ~R 4 are fluorine atoms, that is, the quinone compound a is perfluoro-p-benzoquinone (exemplified compound 3-15) in terms of coloration suppression and polymerization suppression. The fact that the quinone compound a is perfluoro-p-benzoquinone is particularly preferable in terms of availability.

[0035] (Quinone compound b) The quinone compound b is represented by general formula (4). In general formula (4), R 5 ~R 10 each independently represents a hydrogen atom, a fluorine atom, or a chlorine atom.

[0036] R 5 ~R 10 Among them, it is preferable that at least one is a fluorine atom or a chlorine atom, and it is more preferable that at least one is a fluorine atom. In one embodiment, the quinone compound b represented by general formula (4) is a perfluoro compound, that is, it is preferable that all of R 5 ~R 10 in general formula (4) are fluorine atoms.

[0037] Examples of the quinone compound b include the following exemplified compounds. However, the present invention is not limited thereto.

[0038]

Chemical formula

[0039] In general formula (4), R 5 ~R 10 all being fluorine atoms, that is, the quinone compound b being perfluoro-p-naphthoquinone (exemplified compound 4-19), is more preferable in terms of coloring suppression and polymerization suppression.

[0040] In the above stabilization method, a quinone compound is present in the composition containing the perfluorodioxolane compound. The quinone compound added to such a composition can be only one kind in one form and can be two or more kinds in another form. For example, the above composition can contain only one kind or two or more kinds of quinone compound a, can contain only one kind or two or more kinds of quinone compound b, or can contain one or more kinds of quinone compound a and one or more kinds of quinone compound b. Two or more kinds of quinone compounds can be added to the above composition at an arbitrary mixing ratio. When two or more kinds of compounds are used, the content and the addition amount refer to the total amount of these two or more kinds of compounds.

[0041] The addition amount of the quinone compound to the above composition is preferably 0.01 to 500 ppm, more preferably 0.1 to 500 ppm, still more preferably 0.5 to 100 ppm, even more preferably 0.5 to 40 ppm, and even more preferably 1 to 30 ppm in terms of weight ratio with respect to the perfluorodioxolane compound. Even if the amount of the quinone compound is extremely small, it can exhibit a stabilizing effect on the perfluorodioxolane compound, and a sufficient stabilizing effect can be exhibited at an addition amount of 500 ppm or less. From the viewpoint of being able to dispense with or simplify the removal operation of the quinone compound when performing the polymerization reaction, it is preferable that the addition amount of the quinone compound is 500 ppm or less, more preferably 100 ppm or less, and still more preferably 30 ppm or less. On the other hand, from the viewpoint of further enhancing the stabilizing effect, it is preferable that the addition amount of the quinone compound is 0.1 ppm or more, more preferably 0.5 ppm or more, and still more preferably 1 ppm or more. Hereinafter, the unit ppm by weight ratio is also referred to as "weight ppm". Also, from the perspective of using a composition containing a quinone compound in the production of a polymer, the addition amount of the quinone compound is preferably 0.01 to 4.0 ppm, more preferably 0.05 to 2.0 ppm, by weight ratio with respect to the perfluorodioxolane compound.

[0042] The above quinone compound may precipitate or phase-separate without dissolving in the composition containing the above perfluorodioxolane compound. In the composition containing the above perfluorodioxolane compound, it is preferable that the above quinone compound is dissolved, from the perspective of providing a more homogeneous stabilizing effect throughout the perfluorodioxolane compound contained in the composition during storage.

[0043] <Optional component> The composition containing the above perfluorodioxolane compound and quinone compound may also contain one or more other components. Examples of components that can be optionally contained in the above composition include by-products generated during the synthesis of the perfluorodioxolane compound. Such by-products include 2-hydroxy-perfluorodioxolane compounds represented by the following general formula (5).

[0044] [Chemical formula]

[0045] In the formula, Rf 9 , Rf 10 each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and any carbon-carbon bond in the perfluoroalkyl group may have an ether bond. Also, Rf 9 , Rf 10 may be bonded to each other to form a ring. Details of Rf 9 , Rf 10 are the same as the previous description regarding Rf 1 , Rf 2 .

[0046] The above composition may contain, as a 2 - hydro - perfluorodioxolane compound represented by the general formula (5), for example, 2 - hydro - perfluoro(2,4 - dimethyl - 1,3 - dioxolane) having the structure of the following formula (6), which is a by - product in the synthesis process of perfluoro(2 - methylene - 4 - methyl - 1,3 - dioxolane).

[0047] [Chemical formula]

[0048] Generally, the content of the above by - product is less than 10% by weight ratio with respect to the perfluorodioxolane compound.

[0049] Also, the above composition may contain a solvent. The solvent is not particularly limited, but a solvent that dissolves the perfluorodioxolane compound, does not react with the perfluorodioxolane compound, and does not inhibit the polymerization reaction in the next step is preferred. Specific examples of preferred solvents include perfluorohexane, fluorinated linear alkanes such as C6F 13 C2H5, C2F5CHFCHFCF3, etc., fluorinated cyclic alkanes such as c - C5F7H3, fluorinated aromatic compounds such as hexafluorobenzene, trifluoromethylbenzene, perfluorotoluene, etc., fluoroalkyl ethers such as CF3CH2OCF2CF2H, C4F9ОCH3, C4F9ОC2H5, C6F 13 ОCH3, etc., and fluorinated solvents such as perfluorotripropylamine, perfluorotributylamine, etc. The content of the solvent is preferably 0.1 - 10 times the weight ratio with respect to the perfluorodioxolane compound.

[0050] [Container of the composition] As a container for holding the above composition during storage, transportation, etc., for example, resin containers such as polyethylene, polypropylene, polytetrafluoroethylene, etc., metal containers such as stainless steel, glass containers, composite containers of resin and metal, etc. can be mentioned. Among them, resin containers and composite containers of resin and metal are preferred in terms of corrosion resistance, etc.

[0051] The various components contained in the above composition can be introduced into the container simultaneously or sequentially in any order. When there is a gas phase (i.e., space) in the container, it is preferable to make the atmosphere of the gas phase in the container an inert gas atmosphere. Examples of the inert gas include nitrogen, argon, carbon dioxide, etc. By filling the gas phase of the container with an inert gas, the stability against oxidation of the perfluorodioxolane compound can be enhanced.

[0052] <Temperature of the composition> The temperature of the above composition is preferably at or below room temperature, and more preferably maintained at 0°C or below. By setting it at 0°C or below, the stabilization effect can be maintained over a long period, and reactions dependent on temperature such as the dimerization reaction of the perfluorodioxolane compound can be suppressed, thereby enhancing the stabilization effect more effectively. Room temperature can be, for example, about 25°C.

[0053] [Perfluorodioxolane compound-containing composition] Moreover, one aspect of the present invention relates to a perfluorodioxolane compound-containing composition (hereinafter, also referred to as "Composition 1") that contains a perfluorodioxolane compound and a quinone compound, wherein the perfluorodioxolane compound is one or more selected from the group consisting of the perfluorodioxolane compound represented by the above general formula (1) and the perfluorodioxolane compound represented by the above general formula (2), and the quinone compound is one or more selected from the group consisting of the quinone compound represented by the above general formula (3) and the quinone compound represented by the above general formula (4). The details of such a composition are as described above.

[0054] In addition, one aspect of the present invention relates to a perfluorodioxolane compound-containing composition (hereinafter, also referred to as "Composition 2") in which the content of the perfluorodioxolane compound polymer after storage under nitrogen for 1 week or more is 1.0% by weight or less. The above storage refers to storage at room temperature, for example, storage in a storage environment at 25°C. Further, the time point when an arbitrary time has elapsed since the preparation of the perfluorodioxolane compound-containing composition can be set as the start time of the above storage. The above perfluorodioxolane compound-containing composition preferably has a content of the perfluorodioxolane compound polymer of 1.0% by weight or less after storage at room temperature for 30 days under light shielding and nitrogen enclosure. Here, the perfluorodioxolane compound polymer after the above storage means a polymer that can be recovered as a solid residue by drying the perfluorodioxolane compound-containing composition or adding a poor solvent and then filtering. The content of the perfluorodioxolane compound polymer after storage can be, for example, 0.1 weight ppm or more, and can also be less than this value. In one form, it is preferable that no solid residue is confirmed after the above storage.

[0055] In this specification, the matters described for Composition 1 can also be applied to Composition 2, and the matters described for Composition 2 can also be applied to Composition 1.

[0056] [Method for producing perfluorodioxolane compound polymer] In addition, one aspect of the present invention relates to a method for producing a perfluorodioxolane compound polymer (hereinafter, also referred to as "Production Method 1") in which a polymerization initiator is added to a perfluorodioxolane compound-containing composition containing a perfluorodioxolane compound and a quinone compound, and the perfluorodioxolane compound is polymerized. The perfluorodioxolane compound is one or more selected from the group consisting of the perfluorodioxolane compound represented by the general formula (1) and the perfluorodioxolane compound represented by the general formula (2), and the quinone compound is one or more selected from the group consisting of the quinone compound represented by the general formula (3) and the quinone compound represented by the general formula (4).

[0057] The above manufacturing method may be either a method of polymerizing the above composition from which the quinone compound has been removed or a method of polymerizing the above composition without removing the quinone compound. Even without removing the quinone compound, the resulting polymer can be colorless and exhibit sufficient transparency, and since a quinone compound removal step such as distillation purification can be omitted, a method of polymerizing a composition containing a quinone compound is preferred.

[0058] During polymerization, the above composition may contain other monomers. Examples of other monomers include tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, vinylidene fluoride, vinyl fluoride, ethylene, propylene, methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, tert-butyl vinyl ether, 2-ethylhexyl vinyl ether, cyclohexyl vinyl ether, ethylene glycol vinyl ether, diethylene glycol divinyl ether, 1,4-butanediol vinyl ether, 1,4-butanediol divinyl ether, 1,4-cyclohexanedimethanol divinyl ether, 2-chloroethyl vinyl ether, perfluoro(methyl vinyl ether), perfluoro(ethyl vinyl ether), perfluoro(n-propyl vinyl ether), perfluoro(isopropyl vinyl ether), 2-(heptafluoropropoxy)hexafluoropropyl trifluorovinyl ether, perfluoro(3-butenyl vinyl ether), perfluoro(allyl vinyl ether), perfluoro α-olefin (hexafluoropropylene, etc.), (perfluoroalkyl)ethylene ((perfluorobutyl)ethylene, etc.), (perfluoroalkyl)propene (3-perfluorooctyl-1-propene, etc.), perfluoro(alkyl vinyl ether), etc.

[0059] As the polymerization method, polymerization methods such as emulsion polymerization method, solution polymerization method, suspension polymerization method, bulk polymerization method, etc. can be used. As the polymerization method, solution polymerization method and suspension polymerization method are preferable. In the case of the solution polymerization method, in the reactor, the monomer component is polymerized in the polymerization medium in the presence of a polymerization initiator to obtain a mixture containing a fluorine-containing polymer, an unreacted cyclic structure monomer, a polymerization medium, an initiator decomposition product, etc. As the polymerization medium, solvents such as chlorofluorocarbon, hydrochlorofluorocarbon, hydrofluorocarbon, hydrofluoroether, 1,1,2,2,3,3,4-heptafluorocyclopentane, etc. are preferable, and hydrofluorocarbon, hydrofluoroether, 1,1,2,2,3,3,4-heptafluorocyclopentane with low environmental load are more preferable. Examples of the polymerization initiator include perfluorobenzoyl peroxide, etc. The usage amount of the polymerization initiator is preferably 0.01 to 10 parts by mass based on the total amount of the monomer component. The polymerization temperature is preferably 0°C to +100°C. The polymerization time is preferably 1 minute or more and 48 hours or less.

[0060] Further, one aspect of the present invention relates to a method for producing a perfluorodioxolane compound polymer (hereinafter, also referred to as "production method 2") in which a polymerization initiator is added to the above perfluorodioxolane compound-containing composition having a perfluorodioxolane compound polymer content of 1.0% by weight or less after storage under nitrogen for 1 week or more, and the perfluorodioxolane compound is polymerized. The composition to which the polymerization initiator is added can be, in one form, the composition after the above storage, and in another form, the composition that has not been subjected to the above storage.

[0061] In this specification, the matters described for production method 1 can also be applied to production method 2, and the matters described for production method 2 can also be applied to production method 1.

Examples

[0062] The present invention will be specifically described by the following examples, but the present invention is not limited only to these examples. In the analysis, the following equipment was used. GC: Shimadzu GC-2025 Viscometer: Brookfield Digital Viscometer DV-I Prime GPC: Tosoh HLC-8320GPC

[0063] [Example 1] Into a 30 mL polyethylene sample bottle filled with nitrogen, 20.0 g of a perfluorodioxolane compound-containing composition, namely perfluoro(2-methylene-4-methyl-1,3-dioxolane) (GC area percentage = 99.90%, 2-hydroxy-perfluoro(2,4-dimethyl-1,3-dioxolane) GC area percentage = 0.05%) was added. Then, as the quinone compound, 0.0020 g (100 weight ppm) of perfluoro-p-benzoquinone, which is the exemplified compound 3-15 shown above, was added. Thereafter, the sample bottle was shaken at room temperature, and it was visually confirmed that perfluoro-p-benzoquinone was completely dissolved. Then, the sample bottle was stored at room temperature for 30 days under light shielding and nitrogen enclosure. After 30 days of storage, in order to confirm the polymerization inhibitory effect, a part (0.30 g) of the solution after storage was taken and added to 3.0 g of c-C5F7H3 (Zeolora-H manufactured by Nippon Zeon Co., Ltd.), which is a poor solvent for poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)]. As a result, a homogeneous solution was obtained, and it was confirmed that no polymer of perfluoro(2-methylene-4-methyl-1,3-dioxolane) was formed. Furthermore, when a part (1.20 g) of the solution after storage was dried by an evaporator, it was confirmed that there was no residue of solid residue (polymer). That is, it was confirmed that the polymerization inhibitory effect was exhibited. Also, when the color of the solution after storage was visually confirmed, it was colorless. That is, it was also confirmed that coloring was suppressed.

[0064] [Comparative Example 1] The test was conducted in the same manner as in Example 1 except that perfluoro-p-benzoquinone was not added. After 30 days, a portion (0.30 g) of the solution was collected and added to 3.0 g of c-C5F7H3 (Zeolara-H manufactured by Nippon Zeon Co., Ltd.), which is a poor solvent for poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)]. As a result, a white precipitate was formed, suggesting that partial polymerization had proceeded during storage. Also, a portion (1.18 g) of the solution after storage was dried to dryness using an evaporator and then dried under reduced pressure. As a result, a residual solid residue (polymer) of 0.014 g (1.2 wt%) was confirmed.

[0065] [Example 2, Comparative Examples 2 to 4] The same test as in Example 1 was conducted in the same manner except that the compounds shown in Table 1 were present in the perfluoro(2-methylene-4-methyl-1,3-dioxolane) at the concentrations shown in Table 1 as stabilizers. The results are shown in Table 1.

[0066]

Table 1

[0067] From the results shown in Table 1, it can be confirmed that in Example 1 and Example 2, the coloring of the composition after storage was suppressed and an excellent polymerization suppression effect was exhibited. On the other hand, in Comparative Example 2 and Comparative Example 3 in which phenols, which have been conventionally known as stabilizers, were present, the polymerization suppression effect could not be confirmed. In Comparative Example 4 in which DL-α-tocopherol was added, the coloring after storage was significant.

[0068] [Examples 3 to 11, Comparative Example 5] Into a 30 ml polyethylene sample bottle filled with nitrogen, 30.0 g of perfluoro(2-methylene-4-methyl-1,3-dioxolane) (GC area percentage = 99.90%, 2-hydroxy-perfluoro(2,4-dimethyl-1,3-dioxolane) GC area percentage = 0.05%, viscosity = 0.6 mPa·s) was added as a perfluoro(2-methylene-4-methyl-1,3-dioxolane)-containing composition. Next, as a quinone compound, the stabilizer shown in Table 2 was added so as to have the concentration shown in Table 2 to prepare a sample. In Examples 3, 4, 6 to 11 and Comparative Example 5, the sample bottle was stored at room temperature for 30 days under light shielding and nitrogen encapsulation. After 30 days of storage, in order to confirm the progress of polymerization of the content, the viscosity was measured using a viscometer (measurement temperature 20 °C). In Example 5, the sample bottle was stored at -20 °C for 3 months under light shielding and nitrogen encapsulation, and after 3 months of storage, in order to confirm the progress of polymerization of the content, the viscosity was measured using a viscometer (measurement temperature 20 °C). Also, in Examples 3 to 11 and Comparative Example 5, for the samples to which 500 weight ppm of the stabilizer was added, the color of the solution after storage was visually confirmed. The results are shown in Table 2.

[0069]

Table 2

[0070] From the results shown in Table 2, it can be confirmed that in Examples 3 to 11, an excellent stabilizing effect (polymerization inhibition effect) is exhibited even at a low stabilizer concentration. On the other hand, in Comparative Example 5 in which DL-α-tocopherol was present as a stabilizer, it was suggested that the viscosity of the liquid increased and polymerization was progressing at a concentration of less than 100 weight ppm. Further, from the results shown in Table 2, it can be confirmed that in Examples 3 to 11 in which the quinone compound represented by General Formula (3) or General Formula (4) was present, coloring was suppressed as compared with Comparative Example 5 in which DL-α-tocopherol was present. Among them, it can also be confirmed that in Examples 5 and 11 in which a perfluoro compound was present as the quinone compound represented by General Formula (3) or General Formula (4), the coloring suppression effect was large.

[0071] [Examples 12, 13] Into a 30 ml polyethylene sample bottle filled with nitrogen, 25.0 g of perfluoro(2-methylene-4-methyl-1,3-dioxolane) (GC area percentage = 99.27%, 2-hydroxy-perfluoro(2,4-dimethyl-1,3-dioxolane) GC area percentage = 0.46%, viscosity = 0.6 mPa·s) was put as a perfluoro(2-methylene-4-methyl-1,3-dioxolane)-containing composition. Next, as the quinone compound, perfluoro-p-benzoquinone, which is Exemplary Compound 3-15, was added so as to have the concentrations shown in Table 3 to prepare samples. In Example 12, the sample bottle was stored at room temperature for 90 days under light shielding and nitrogen enclosure. After 90 days of storage, in order to confirm the progress of polymerization of the content, the viscosity was measured using a viscometer (measurement temperature: 20°C). Also, for each sample, the color of the solution after storage was visually confirmed. In Example 13, the sample bottle was stored at -20°C for 6 months under light shielding and nitrogen enclosure, and after 6 months, in order to confirm the progress of polymerization of the content, the viscosity was measured using a viscometer (measurement temperature: 20°C). Also, for each sample, the color of the solution after storage was visually confirmed. The results are shown in Table 3.

[0072]

Table 3

[0073] From the results shown in Table 3, it can be confirmed that in Example 12 and Example 13, an excellent stabilization effect (polymerization inhibition effect) is exhibited even at a low stabilizer concentration.

[0074] [Example 14, Comparative Example 6] In a glass tube (internal volume 100 mL), 10 g of perfluoro(2-methylene-4-methyl-1,3-dioxolane) containing 10 weight ppm of perfluoro-p-benzoquinone, which is Exemplary Compound 3-15 as a quinone compound (GC area percentage = 99.90%, 2-hydro-perfluoro(2,4-dimethyl-1,3-dioxolane) GC area percentage = 0.05%), 40 g of c-C5F7H3 (Zeoroller-H manufactured by Nippon Zeon Co., Ltd.) as a polymerization solvent, and 0.086 g of perfluorobenzoyl peroxide as a polymerization initiator were placed, and the mixture was reacted at 55 °C for 24 hours. After the reaction, the resulting precipitate was filtered to obtain poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)]. The yield and molecular weight (GPC method) of the obtained polymer were compared with those of Comparative Example 6 in which the same operation was carried out without adding a stabilizer. The results are shown in Table 4 as shown below.

[0075]

Table 4

[0076] From the results shown in Table 4, it can be confirmed that in Example 14, it was not necessary to perform an operation for removing the stabilizer by distillation purification or the like before polymerization, and the polymerization reaction could proceed in the same manner as in the case of not containing the stabilizer.

[0077] According to one aspect of the present invention, it has become possible to provide a composition containing a perfluorodioxolane compound that is less likely to cause quality changes such as polymerization reaction and coloring during storage. The composition containing the perfluorodioxolane compound thus stabilized can be used as a synthetic raw material for a resin for a gas separation membrane and a transparent resin for an optical fiber.

Claims

1. Comprising the presence of a quinone compound in a composition containing a perfluorodioxolane compound, wherein the perfluorodioxolane compound is the following general formula (1): 【Chemical 1】 (wherein, Rf １ , Rf ２ each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and may have an ether bond between any carbon-carbon bonds of the perfluoroalkyl group. Further, Rf １ , Rf ２ may be bonded to each other to form a ring.) a perfluorodioxolane compound represented by, and the following general formula (2): 【Chemical 2】 (wherein, Rf ３ , Rf ４ each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and may have an ether bond between any carbon-carbon bonds of the perfluoroalkyl group.) a perfluorodioxolane compound represented by, is one or more selected from the group consisting of, wherein the quinone compound is the following general formula (3): 【Chemical Formula 3】 (wherein, R １ ~R ４ each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.) a quinone compound represented by, and the following general formula (4): 【Chemical Formula 4】 (wherein, R ５ ~R １０ each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.) a quinone compound represented by, A method for stabilizing a perfluorodioxolane compound, which is one or more selected from the group consisting of.

2. R in the general formula (3) １ ~R ４ The method for stabilizing a perfluorodioxolane compound according to claim 1, wherein at least one of them is a fluorine atom.

3. The method for stabilizing a perfluorodioxolane compound according to claim 1 or 2, wherein the quinone compound comprises a quinone compound represented by general formula (3).

4. The method for stabilizing a perfluorodioxolane compound according to any one of claims 1 to 3, wherein the quinone compound comprises perfluoro-p-benzoquinone.

5. R in the general formula (4) ５ ~R １０ The method for stabilizing a perfluorodioxolane compound according to any one of claims 1 to 4, wherein at least one of them is a fluorine atom.

6. The method for stabilizing a perfluorodioxolane compound according to any one of claims 1 to 5, wherein the quinone compound is present in a weight ratio of 0.1 to 500 ppm with respect to the perfluorodioxolane compound.

7. The method for stabilizing a perfluorodioxolane compound according to claim 6, further comprising holding the composition in which the quinone compound is present in a container and making the atmosphere in the gas phase part of the container an inert gas atmosphere.

8. The method for stabilizing a perfluorodioxolane compound according to any one of claims 1 to 7, further comprising maintaining the temperature of the composition in which the quinone compound is present at 0 °C or lower.

9. Containing a perfluorodioxolane compound and a quinone compound, wherein the perfluorodioxolane compound is the following general formula (1): 【Chemical Formula 5】 (wherein, Rf １ , Rf ２ each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and may have an ether bond between any carbon-carbon bonds of the perfluoroalkyl group. Further, Rf １ , Rf ２ may be bonded to each other to form a ring.) a perfluorodioxolane compound represented by, and the following general formula (2): ​ (wherein, Rf ３ , Rf ４ each independently represents a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and may have an ether bond between any carbon-carbon bonds of the perfluoroalkyl group.) a perfluorodioxolane compound represented by, is one or more selected from the group consisting of, wherein the quinone compound is the following general formula (3): 【Chemical Formula 7】 (wherein, R １ ~R ４ each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.) a quinone compound represented by, and the following general formula (4): 【Chemical 8】 (wherein, R ５ ~R １０ each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.) a quinone compound represented by, A composition containing a perfluorodioxolane compound, which is one or more selected from the group consisting of.

10. The composition containing a perfluorodioxolane compound according to claim 9, wherein the quinone compound is contained in a weight ratio of 0.1 to 500 ppm with respect to the perfluorodioxolane compound.

11. R in the general formula (3) １ ~R ４ The perfluorodioxolane compound-containing composition according to claim 9 or 10, wherein at least one of them is a fluorine atom.

12. The quinone compound-containing composition according to any one of claims 9 to 11, wherein the quinone compound contains a quinone compound represented by the general formula (3).

13. The quinone compound-containing composition according to any one of claims 9 to 12, wherein the quinone compound contains perfluoro-p-benzoquinone.

14. R in the general formula (4) ５ ~R １０ The perfluorodioxolane compound-containing composition according to any one of claims 9 to 13, wherein at least one of them is a fluorine atom.

15. A method for producing a perfluorodioxolane compound polymer, comprising adding a polymerization initiator to the perfluorodioxolane compound-containing composition according to any one of claims 9 to 14 and polymerizing the perfluorodioxolane compound.

16. A perfluorodioxolane compound-containing composition, wherein the perfluorodioxolane compound is represented by the following general formula (1): 【Chemical Formula 9】 (In the formula, Rf1 and Rf2 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and an ether bond may be present between any carbon-carbon bonds of the perfluoroalkyl group. Further, Rf1 and Rf2 may be bonded to each other to form a ring.) a perfluorodioxolane compound represented by, and the following general formula (2): 【Chemical 10】 (In the formula, Rf3 and Rf4 each independently represent a fluorine atom or a perfluoroalkyl group having 1 to 6 carbon atoms, and an ether bond may be present between any carbon-carbon bonds of the perfluoroalkyl group.) a perfluorodioxolane compound represented by, and is at least one selected from the group consisting of the perfluorodioxolane compound-containing composition further contains a quinone compound represented by the following general formula (3): 【Chemical 11】 (wherein, R １ to R ４ each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.) and a quinone compound represented by the following general formula (4): 【Chemical Formula 12】 (wherein, R ５ to R １０ each independently represents a hydrogen atom, a fluorine atom or a chlorine atom.) and is at least one quinone compound selected from the group consisting of and the content of the perfluorodioxolane compound polymer after storage under nitrogen for 1 week or more is 1.0% by weight or less. A perfluorodioxolane compound-containing composition.

17. A method for producing a perfluorodioxolane compound polymer, comprising adding a polymerization initiator to the perfluorodioxolane compound-containing composition according to claim 16 without performing the step of removing the quinone compound or after performing the step of removing the quinone compound, and polymerizing the perfluorodioxolane compound.

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