JP6813003B2 - Method for producing perfluoroalkaziene compound - Google Patents

Description

The present disclosure relates to a method for producing a perfluoroalkaziene compound.

The perfluoroalkadiene compound is a compound useful as a dry etching gas for semiconductors, various refrigerants, foaming agents, heat transfer media, etc., and has two double bonds between carbon and carbon. In particular, hexafluorobutadiene having four carbon atoms and having double bonds at both ends is utilized in various applications.

As a method for producing this perfluoroalkaziene compound, ICF ₂ CF ₂ CF ₂ CF ₂ I is used as a reactant using an organometallic compound such as Mg, Zn, Cd, or Li at a desired temperature in the presence of an organic solvent. A method is known by de-IFing a compound such as (see, for example, Patent Document 1). On the other hand, as a method for producing a perfluoroalkadiene compound, it is also known that de-IF of a compound such as ICF ₂ CF ₂ CF ₂ CF ₂ I is performed in the presence of metallic zinc and a nitrogen-containing compound (for example, a patent). Reference 2).

Japanese Unexamined Patent Publication No. 62-26240 Japanese Unexamined Patent Publication No. 2001-192345

An object of the present disclosure is to provide a method capable of obtaining a perfluoroalkadiene compound in a high yield while reducing the amount of impurities that are difficult to separate.

The present disclosure includes the following configurations.
Item 1. General formula (1):
CF ₂ = CF-(CF ₂ ) _n-4 -CF = CF ₂ (1)
[In the formula, n indicates an integer from 4 to 20. ]
It is a method for producing a perfluoroalkadiene compound represented by.
In an organic solvent, in the presence of nitrogen-containing compounds, as well as zinc or zinc alloys,
General formula (2):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF ₂ -CF ₂ X ³ (2)
[In the formula, n is the same as above. X ¹ , X ² and X ³ are the same or different, X ¹ and X ² represent halogen atoms, and X ³ represents chlorine, bromine or iodine atoms. However, both X ¹ and X ² do not become fluorine atoms. ]
Equipped with a reaction step for reacting the compound represented by
The reaction step is a production method including a mixing step of sequentially mixing a solution containing zinc or a zinc alloy and an organic solvent, a nitrogen-containing compound, and the compound represented by the general formula (2).
Item 2. The mixing step includes a step of mixing a solution containing zinc or a zinc alloy and an organic solvent with a nitrogen-containing compound.
Item 2. The production method according to Item 1, wherein the nitrogen-containing compound is added to a solution containing the zinc or zinc alloy and an organic solvent at an addition rate of 0.1 to 600 mol / hour with respect to 1 mol of the zinc or zinc alloy.
Item 3. In the mixing step, a solution containing the zinc or zinc alloy and an organic solvent is mixed with the compound represented by the general formula (2), and then the obtained mixed solution and the nitrogen-containing compound are mixed. Item 2. The production method according to Item 1 or 2.
Item 4. In the mixing step, a solution containing the zinc or zinc alloy and an organic solvent is mixed with the nitrogen-containing compound, and then the obtained mixed solution and the compound represented by the general formula (2) are mixed. , Item 1 or 2.
Item 5. In the mixing step, the compound represented by the general formula (2) is added to 1 mol of the zinc or zinc alloy with respect to the mixed solution of the solution containing the zinc or zinc alloy and the organic solvent and the nitrogen-containing compound. Item 4. The production method according to Item 4, wherein the zinc is added at an addition rate of 0.05 to 30 mol / hour.
Item 6. Item 5. The method according to any one of Items 3 to 5, wherein the mixing step is a temperature of 50 to 200 ° C. when the solution containing the zinc or zinc alloy and the organic solvent is mixed with the nitrogen-containing compound. Manufacturing method.
Item 7. Item 8. The production method according to any one of Items 1 to 6, wherein the nitrogen-containing compound is N, N-dimethylformamide.
Item 8. Item 8. The production method according to any one of Items 1 to 7, wherein the boiling point of the organic solvent is equal to or lower than the boiling point of the nitrogen-containing compound.
Item 9. General formula (1):
CF ₂ = CF-(CF ₂ ) _n-4 -CF = CF ₂ (1)
[In the formula, n indicates an integer from 4 to 20. ]
With the perfluoroarcdiene compound represented by
General formula (3):
CF ₂ = CF-(CF ₂ ) _n-4 -CF ₂ -CF ₂ H (3)
[In the formula, n is the same as above. ]
And the compound represented by
General formula (4A):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF = CF ₂ (4A)
[In the formula, n is the same as above. X ¹ and X ² are the same or different and represent halogen atoms. However, both X ¹ and X ² do not become fluorine atoms. ]
Compound represented by and / or general formula (4B):
CF ₂ H-CFX ^2- (CF ₂ ) _n-4 -CF _{2 -} CF ₂ H (4B)
[In the formula, n is the same as above. X ² indicates a halogen atom. ]
And the compound represented by
General formula (5):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF ₂ -CF ₂ H (5)
[In the formula, n is the same as above. X ¹ and X ² are the same or different and represent halogen atoms. However, both X ¹ and X ² do not become fluorine atoms. ]
A perfluoroalkaziene composition containing a compound represented by.
Item 10. Item 2. The perfluoroalkane compound according to Item 9, wherein the content of the perfluoroalkaziene compound represented by the general formula (1) is 30 to 99.8 mol%, where the total amount of the perfluoroalkaziene composition is 100 mol%. Diene composition.
Item 11. Item 9. The perfluoroalkaziene composition according to Item 9 or 10, wherein the perfluoroalkaziene compound represented by the general formula (1) is hexafluorobutadiene.
Item 12. Item 9. An etching gas, a refrigerant, a heat transfer medium, a foaming agent, or a resin monomer comprising the perfluoroarcdiene composition according to any one of Items 9 to 11.

According to the present disclosure, a perfluoroalkaziene compound can be obtained in a high yield while reducing the amount of impurities that are difficult to separate.

As used herein, "contains" is a concept that includes any of "comprise," "consist essentially of," and "consist of." Further, in the present specification, when the numerical range is indicated by "A to B", it means A or more and B or less.

The method for producing the perfluoroalkadiene compound of the present disclosure is described in the general formula (1):
CF ₂ = CF-(CF ₂ ) _n-4 -CF = CF ₂ (1)
[In the formula, n indicates an integer from 4 to 20. ]
It is a method for producing a perfluoroalkadiene compound represented by.
In an organic solvent, in the presence of nitrogen-containing compounds, as well as zinc or zinc alloys,
General formula (2):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF ₂ -CF ₂ X ³ (2)
[In the formula, n is the same as above. X ¹ , X ² and X ³ are the same or different, X ¹ and X ² represent halogen atoms, and X ³ represents chlorine, bromine or iodine atoms. However, both X ¹ and X ² do not become fluorine atoms. ]
The reaction step includes a reaction step of reacting the compound represented by (1), and the reaction step includes a mixing step of mixing a nitrogen-containing compound with a solution containing zinc or a zinc alloy and an organic solvent.

In the present disclosure, the yield is higher than that of the methods of Patent Documents 1 and 2, and 1,1,1,2,4,4,4-heptafluoro-2-butene and the like are separated as compared with Patent Document 2. The desired product can be obtained by suppressing difficult impurities.

In particular, the compound represented by the general formula (2) has CF ₂ X ³ and the adjacent group is CF ₂ , so ClCF ₂ CFClCF ₂ CF ₂ H, ICF ₂ CF ₂ CF ₂ CF ₂ H, BrCF ₂ Impurities such as CF ₂ CF ₂ CF ₂ H (compounds represented by the general formula (5) described later) are formed in the liquid phase of the collection cylinder and are hardly present in the gas phase. Therefore, it is an impurity that does not cause a problem when only the gas phase of the collecting cylinder is collected, but it is an impurity that becomes a problem when collecting the gas phase and the liquid phase of the collecting cylinder as described later. In the present disclosure, as described above, a solution containing a zinc or zinc alloy and an organic solvent and a nitrogen-containing compound are mixed (in particular, the nitrogen-containing compound is added to a solution containing zinc or a zinc alloy and an organic solvent). Therefore, the amount of this impurity produced can be reduced.

In the general formulas (1) and (2), n is an integer of 4 to 20, more preferably an integer of 4 to 10. Within this range, a perfluoroarcdiene compound can be obtained in a higher yield while reducing the amount of impurities that are difficult to separate.

That is, the perfluoroalkaziene compounds represented by the general formula (1) to be produced are hexafluorobutadiene (CF ₂ = CF-CF = CF ₂ ) and octafluoropentadiene (CF ₂ = CF-CF ₂ -CF). = CF ₂ ), decafluorohexadiene (CF ₂ = CF-CF ₂ -CF ₂ -CF = CF ₂ ) and the like.

In the general formula (2), X ¹ and X ² are halogen atoms, and examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. In the general formula (2), X ³ is a chlorine atom, a bromine atom or an iodine atom. X ¹ , X ² and X ³ may be the same or different. However, when both X ¹ and X ² become fluorine atoms, the reaction does not proceed and a perfluoroarcdiene compound cannot be obtained. Therefore, both X ¹ and X ² do not become fluorine atoms. Among them, X ¹ includes chlorine atom, bromine atom, iodine atom and the like (particularly chlorine atom) from the viewpoint that a perfluoroalkaziene compound can be obtained in a higher yield while reducing the amount of impurities that are difficult to separate. , Bromine atom, etc.) is preferable, as X ² , fluorine atom, chlorine atom, bromine atom, etc. (particularly fluorine atom, chlorine atom, etc.) are preferable, and as X ³ , chlorine atom, bromine atom, iodine atom, etc. (particularly bromine atom, etc.) are preferable. , Iodine atom, etc.) is preferable.

Examples of the compound represented by satisfying such conditions the general formula (2), for _{example, ClCF 2 -CFCl-CF 2 -CF} 2 I, ClCF 2 -CFCl-CF 2 -CF 2 -CF 2 I, ClCF 2 -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ I, ICF ₂ -CF ₂ -CF ₂ -CF ₂ I, ICF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ I, ICF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ I, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ Br, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ Br, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ Br etc. can be mentioned, and ClCF ₂ -CFCl can be obtained from the viewpoint of obtaining a perfluoroalkadiene compound in a higher yield while reducing the amount of impurities that are difficult to separate. -CF ₂ -CF ₂ I, ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ I, ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ I, BrCF ₂ -CF ₂ -CF _2- CF ₂ Br, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ Br, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ Br, etc. are preferable, ClCF ₂ -CFCl-CF _2- CF ₂ I, ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ I, ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ I, etc. are more preferable.

The amount of the compound represented by the general formula (2) is the zinc or zinc alloy described later from the viewpoint of obtaining a perfluoroalkaziene compound in a higher yield while reducing the amount of impurities that are difficult to separate. With respect to 1 mol, 0.05 to 30 mol is preferable, 0.1 to 10 mol is more preferable, and 0.2 to 5 mol is further preferable.

In zinc or zinc alloy, examples of elements that can be contained when a zinc alloy is used include lead, cadmium, iron and the like. Commercially available zinc may contain impurities such as lead, cadmium, and iron. The present disclosure also includes those containing these impurities.

As the organic solvent, a non-polar organic solvent is particularly preferable from the viewpoint of dissolving a compound represented by the general formula (2) or the like. The boiling point of this organic solvent is preferably equal to or lower than the boiling point of the nitrogen-containing compound from the viewpoint of suppressing volatilization of the nitrogen-containing compound from the reaction system and particularly improving the yield of the perfluoroalkaziene compound. Examples of such an organic solvent include aromatic hydrocarbon compounds such as heptane, hexane, benzene, toluene and xylene; ether compounds such as tetrahydrofuran and diethyl ether.

The amount of the organic solvent used is not particularly limited as long as it is the amount of the solvent, and is preferably 0.01 to 10 mol, more preferably 0.1 to 5 mol, with respect to 1 mol of zinc or zinc alloy.

The nitrogen-containing compound is not particularly limited as long as it contains a nitrogen atom, and is, for example, an amide compound (N, N-dimethylformamide, N, N-diisopropylformamide, etc.), an amine compound (triethylamine, etc.), a pyridine compound. (Pyridine, methylpyridine, N-methyl-2-pyrrolidone, etc.), quinoline compounds (quinolin, methylquinolin, etc.) and the like can be mentioned. These nitrogen-containing compounds can be used alone or in combination of two or more. Of these, an amide compound is preferable, and N, N-dimethylformamide is more preferable, from the viewpoint of obtaining a perfluoroalkadiene compound in a higher yield while reducing the amount of impurities that are difficult to separate.

Although this nitrogen-containing compound includes a compound that is liquid at room temperature, it is not a solvent but an additive from the viewpoint of obtaining a perfluoroalkadiene compound in a higher yield while reducing the amount of impurities that are difficult to separate. It is preferable to use as (use in a small amount). The amount of the nitrogen-containing compound used is preferably 0.25 to 4 mol, more preferably 0.5 to 2 mol, based on 1 mol of zinc or zinc alloy.

In the production method of the present disclosure, the above-mentioned mixing step contains zinc or a zinc alloy and an organic solvent from the viewpoint of obtaining a perfluoroalkaziene compound in a higher yield while reducing the amount of impurities that are difficult to separate. It is preferable to sequentially mix the solution, the nitrogen-containing compound, and the compound represented by the general formula (2). In such a mixing step, for example, a solution containing zinc or a zinc alloy and an organic solvent is mixed with a nitrogen-containing compound, and in particular, a nitrogen-containing compound is added to a solution containing zinc or a zinc alloy and an organic solvent. can do. In a solution containing zinc or a zinc alloy and an organic solvent, the content of each component is preferably adjusted so as to satisfy the content ratio of each component described above. When the compound represented by the general formula (2) is mixed (particularly added) in a later step, the amount of the compound represented by the general formula (2) to be mixed (particularly added) should be taken into consideration. It is preferable to adjust the content of each component with.

When mixing a solution containing zinc or zinc alloy and an organic solvent with a nitrogen-containing compound (adding a nitrogen-containing compound to a solution containing zinc or zinc alloy and an organic solvent), zinc or zinc alloy and an organic solvent The solution containing zinc is preferably mixed with the nitrogen-containing compound at a temperature of preferably 50 to 200 ° C, more preferably 100 to 150 ° C. In particular, it is preferable to add the nitrogen-containing compound while heating the solution containing zinc or a zinc alloy and an organic solvent to the above temperature. In addition, by adding a nitrogen-containing compound while refluxing a solution containing zinc or a zinc alloy and an organic solvent, the solvent volatilizes when the reaction temperature is reached because the solvent is lower than the reaction temperature, and the solvent is cooled and returned to the reactor. be able to. When a nitrogen-containing compound is added while refluxing a solution containing zinc or a zinc alloy and an organic solvent, it is most preferable to heat the solution containing zinc or a zinc alloy and an organic solvent at a reflux temperature.

When the boiling point of the organic solvent is equal to or lower than the boiling point of the nitrogen-containing compound, it is preferable that the solution containing the zinc or zinc alloy and the organic solvent is heated and then mixed easily when the solution and the nitrogen-containing compound are mixed.

After heating (particularly heating at reflux temperature), a solution containing zinc or a zinc alloy and an organic solvent is mixed with a nitrogen-containing compound, for example, when a nitrogen-containing compound is added to a solution containing zinc or a zinc alloy and an organic solvent. The addition rate (drop rate) is zinc or zinc or from the viewpoint of obtaining a perfluoroalkadiene compound represented by the general formula (1) in a higher yield while reducing the amount of impurities that are difficult to separate. 0.1 to 600 mol / hour is preferable, and 0.33 to 60 mol / hour is more preferable with respect to 1 mol of the zinc alloy. The addition time is preferably such that the reaction proceeds sufficiently, and in particular, it is preferable to adjust the addition time so that the total amount of the nitrogen-containing compound added is within the above range. Specifically, the addition time is preferably 0.002 to 10 hours, more preferably 0.02 to 3 hours.

In the production method of the present disclosure described above, a solution containing a zinc or zinc alloy and an organic solvent and a nitrogen-containing compound are mixed (in particular, the nitrogen-containing compound is added to the solution containing zinc or a zinc alloy and an organic solvent). In this case, the compound represented by the general formula (2), which is a substrate, may be a mixture of a mixed solution obtained after mixing with a solution containing a zinc or zinc alloy and an organic solvent and a nitrogen-containing compound (hereinafter,). "Substrate pre-addition" is also referred to), and a solution containing a zinc or zinc alloy and an organic solvent is mixed with a nitrogen-containing compound (in particular, the nitrogen-containing compound is added to a solution containing a zinc or zinc alloy and an organic solvent). After that, the mixed solution thus obtained is mixed with the compound represented by the general formula (2) which is a substrate (in particular, the mixed solution thus obtained is mixed with the general formula (2) which is a substrate. The compound represented by (addition) may be added (hereinafter, may be referred to as “post-substrate addition”). Among these, by reacting zinc or a zinc alloy with a nitrogen-containing compound in advance, the compound represented by the general formula (2) reacts with the nitrogen-containing compound to generate impurities that are difficult to separate. Post-substrate addition is particularly preferable from the viewpoint of further suppressing the above-mentioned amount and, as a result, further improving the yield of the perfluoroalkaziene compound.

When substrate pre-addition is adopted, the content of the compound represented by the general formula (2) contained in the solution containing zinc or a zinc alloy and an organic solvent is adjusted so as to satisfy the content ratio of each component described above. Is preferable.

When post-substrate addition is adopted, after adding the nitrogen-containing compound to a solution containing zinc or a zinc alloy and an organic solvent, the compound represented by the general formula (2) which is a substrate in the mixed solution thus obtained is obtained. The addition rate (drop rate) of the compound represented by the general formula (2) when the compound is added is the perfluoroalkaziene compound represented by the general formula (1) while reducing the amount of impurities that are difficult to separate. From the viewpoint of obtaining a higher yield, 0.05 to 30 mol / hour is preferable, and 0.17 to 6 mol / hour is more preferable with respect to 1 mol of zinc or a zinc alloy. The addition time is preferably such that the reaction proceeds sufficiently, and in particular, it is preferable to adjust the addition time so that the total amount of the compound represented by the general formula (2) added is within the above range. Specifically, the addition time is preferably 0.02 to 10 hours, more preferably 0.08 to 3 hours.

In the present disclosure, iodine-containing inorganic materials can also be used in the reaction. As a result, it is possible to obtain a perfluoroalkadiene compound represented by the general formula (1) in a higher yield while reducing the amount of impurities that are difficult to separate.

The iodine-containing inorganic material is not particularly limited as long as it is an inorganic material containing an iodine atom. For example, iodine; typical metal iodide (sodium iodide, potassium iodide, magnesium iodide, calcium iodide, etc.), transition Examples thereof include metal iodides such as metal iodides (zinc iodide and the like). According to the production method of the present disclosure, zinc halide (a mixture of zinc fluoride, zinc chloride and zinc iodide) can be produced as an impurity in the product. It is also possible to use zinc halide as an impurity contained in this product as an iodine-containing inorganic material and reuse it in the production method of the present disclosure. These iodine-containing inorganic materials can be used alone or in combination of two or more. Among them, as impurities in iodine, transition metal iodide, and products produced by the production method of the present disclosure, from the viewpoint of obtaining a perfluoroalkaziene compound in a higher yield while reducing the amount of impurities that are difficult to separate. Zinc halide and the like are preferable, and iodine is more preferable.

The amount of this iodine-containing inorganic compound used is 0.0005 mol or more per 1 mol of zinc or zinc alloy from the viewpoint of obtaining a perfluoroalkaziene compound in a higher yield while reducing the amount of impurities that are difficult to separate. It is preferably less than or equal to the solubility of the organic solvent, and more preferably 0.001 to 0.1 mol with respect to 1 mol of zinc or zinc alloy.

When the iodine-containing inorganic material is used in the present disclosure, regardless of whether the substrate is added before or after the substrate is added, the amount of impurities that are difficult to separate is reduced and the solvent is represented by the general formula (1). In order to obtain a fluoroalkaziene compound in a higher yield, the iodine-containing inorganic material is preferably contained in a solution containing zinc or a zinc alloy and an organic solvent. In this case, it is preferable to adjust the content of the iodine-containing inorganic material contained in the solution containing zinc or a zinc alloy and an organic solvent so as to satisfy the content ratio of each of the above-mentioned components.

The reaction conditions other than the above are not particularly limited. For example, the reaction atmosphere is preferably an inert gas atmosphere (nitrogen gas atmosphere, argon gas atmosphere, etc.), and the reaction time (maintenance time at the maximum temperature reached) is sufficient. It can be as advanced as possible. After completion of the reaction, purification treatment is carried out according to a conventional method to obtain a perfluoroalkaziene compound represented by the general formula (1).

According to such a production method of the present disclosure, the yield of the perfluoroarcdiene compound represented by the general formula (1) is increased while reducing the amount of impurities that are difficult to separate, and the compounds are separated. It is possible to efficiently obtain the perfluoroalkaziene compound represented by the general formula (1) while reducing the labor for isolating difficult impurities. Impurities that are difficult to separate are 1,1,1,2,4,4,4-hepta, for example, when hexafluorobutadiene is to be obtained as the perfluoroalkaziene compound represented by the general formula (1). Fluoro-2-butene (CF ₃ CF = CHCF ₃ ) and the like can be mentioned.

The perfluoroalkadiene compound represented by the general formula (1) thus obtained includes an etching gas for forming a state-of-the-art fine structure such as a semiconductor and a liquid crystal, a refrigerant, a heat transfer medium, and foaming. It can be effectively used for various purposes such as agents and resin monomers.

In this way, the perfluoroalkaziene compound represented by the general formula (1) can be obtained, and the perfluoroalkaziene compound represented by the general formula (1) and the general formula (3):
CF ₂ = CF-(CF ₂ ) _n-4 -CF ₂ -CF ₂ H (3)
[In the formula, n is the same as above. ]
Compound represented by and general formula (4A):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF = CF ₂ (4A)
[In the formula, n is the same as above. X ¹ and X ² are the same or different and represent halogen atoms. However, both X ¹ and X ² do not become fluorine atoms. ]
Compound represented by and / or general formula (4B):
CF ₂ H-CFX ^2- (CF ₂ ) _n-4 -CF _{2 -} CF ₂ H (4B)
[In the formula, n is the same as above. X ² indicates a halogen atom. ]
Compound represented by and general formula (5):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF ₂ -CF ₂ H (5)
[In the formula, n is the same as above. X ¹ and X ² are the same or different and represent halogen atoms. However, both X ¹ and X ² do not become fluorine atoms. ]
It may also be obtained in the form of a perfluoroalkaziene composition containing a compound represented by.

Examples of the compound represented by satisfying such conditions the general formula (3), for _{example, CF 2 = CF-CF 2} -CF 2 H, CF 2 = CF-CF 2 -CF 2 -CF 2 H, CF 2 = CF-CF ₂ -CF ₂ -CF ₂ -CF ₂ H etc.

In the general formula (4A), X ¹ and X ² are halogen atoms, and examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. X ¹ and X ² may be the same or different. However, as in the general formula (2), both X ¹ and X ² do not become fluorine atoms. Similar to the general formula (2), X ¹ is preferably chlorine atom, bromine atom, iodine atom, etc. (particularly chlorine atom, bromine atom, etc.), and X ² is fluorine atom, chlorine atom, bromine atom, etc. (particularly fluorine). Atoms, chlorine atoms, etc.) are preferred. Examples of the compound represented by the formula (4A), for _{example, ClCF 2 -CFCl-CF = CF} 2, ClCF 2 -CFCl-CF 2 -CF = CF 2, ClCF 2 -CFCl-CF 2 -CF ₂ -CF = CF ₂ , ICF ₂ -CF ₂ -CF = CF ₂ , ICF ₂ -CF ₂ -CF ₂ -CF = CF ₂ , ICF ₂ -CF ₂ -CF ₂ -CF ₂ -CF = CF ₂ , BrCF ₂ -CF ₂ -CF = CF ₂ , BrCF ₂ -CF ₂ -CF ₂ -CF = CF ₂ , BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF = CF ₂ etc., general formula (2) For the same reason as ClCF ₂ -CFCl-CF = CF ₂ , ClCF ₂ -CFCl-CF ₂ -CF = CF ₂ , ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF = CF ₂ , BrCF ₂ -CF ₂ -CF = CF ₂ , BrCF ₂ -CF ₂ -CF ₂ -CF = CF ₂ , BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF = CF ₂ etc. are preferable, ClCF ₂ -CFCl-CF = CF ₂ , ClCF ₂ -CFCl-CF ₂ -CF = CF ₂ , ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF = CF _{2 and the} like are more preferable.

In the general formula (4B), X ² is a halogen atom, and examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Similar to the general formula (2), as X ² , fluorine atoms, chlorine atoms, bromine atoms and the like (particularly fluorine atoms, chlorine atoms and the like) are preferable. Examples of the compound represented by satisfying such conditions the general formula (4B), for _{example, HCF 2 -CFCl-CF 2 -CF} 2 H, HCF 2 -CFCl-CF 2 -CF 2 -CF 2 H, HCF 2 -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ H, HCF ₂ -CF ₂ -CF ₂ -CF ₂ H, HCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H, HCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H, etc. For the same reason as general formula (2), HCF ₂ -CFCl-CF ₂ -CF ₂ H, HCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ H, HCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ H, etc. are preferable.

In the general formula (5), X ¹ and X ² are halogen atoms, and examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. X ¹ and X ² may be the same or different. However, as in the general formula (2), both X ¹ and X ² do not become fluorine atoms. Similar to the general formula (2), X ¹ is preferably chlorine atom, bromine atom, iodine atom, etc. (particularly chlorine atom, bromine atom, etc.), and X ² is fluorine atom, chlorine atom, bromine atom, etc. (particularly fluorine). Atoms, chlorine atoms, etc.) are preferred. The compound represented by the general formula (5) is a compound produced because the group represented by the general formula (2), which is a substrate, is CF ₂ and the group adjacent to the CF ₂ X ₃ group is CF _2. Since it occurs abundantly in the liquid phase and hardly exists in the gas phase, it is not detected when only the gas phase of the collecting cylinder is analyzed. That is, the perfluoroalkadiene composition of the present disclosure is composed of impurities present in both the gas phase and the liquid phase of the collecting cylinder, and when collected only from the gas phase of the collecting cylinder, the present invention is used. The disclosed perfluoroalkaziene composition is not available. Examples of the compound represented by satisfying such conditions the general formula (5), for _{example, ClCF 2 -CFCl-CF 2 -CF} 2 H, ClCF 2 -CFCl-CF 2 -CF 2 -CF 2 H, ClCF 2 -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ H, ICF ₂ -CF ₂ -CF ₂ -CF ₂ H, ICF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H, ICF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ H, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H etc. are mentioned, and for the same reason as the general formula (2), ClCF ₂ -CFCl-CF ₂ -CF ₂ H, ClCF ₂ -CFCl-CF ₂ -CF _2- CF ₂ H, ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ -CF ₂ H, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ H, BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H , BrCF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ -CF ₂ H, etc. are preferable, ClCF ₂ -CFCl-CF ₂ -CF ₂ H, ClCF ₂ -CFCl-CF ₂ -CF ₂ -CF ₂ H, ClCF ₂ -CF Cl-CF ₂ -CF ₂ -CF ₂ -CF ₂ H etc. are more preferable.

In the perfluoroalkaziene composition of the present disclosure, the content of the perfluoroalkaziene compound represented by the general formula (1) is 30 to 99.8, assuming that the total amount of the perfluoroalkaziene composition of the present disclosure is 100 mol%. The molar% (particularly 50 to 99 mol%) is preferable, and the content of the compound represented by the general formula (3) is preferably 0.1 to 30 mol% (particularly 2 to 25 mol%), and the general formula (4A) and / Alternatively, the total content of the compound represented by (4B) is preferably 0.01 to 5 mol% (particularly 0.02 to 3 mol%), and the content of the compound represented by the general formula (5) is 0.05 to 35 mol% (particularly 0.02 to 3 mol%). In particular, 0.1 to 5 mol%) is preferable. Further, in the perfluoroarcdiene composition of the present disclosure, the content of components (other components) other than the above is preferably 0 to 30 mol% (particularly 0.01 to 10 mol%). In the present disclosure, in the compound represented by the general formula (2) which is a substrate, the compound represented by the general formula (5) is generated in the liquid phase because the group adjacent to the CF ₂ X ₃ group is CF _2. However, even in that case, it is possible to reduce the amount of the compound represented by the general formula (5) produced. In addition, when trying to obtain hexafluorobutadiene as a perfluoroalkadiene compound represented by the general formula (1), which is difficult to separate into other components, 1,1,1,2,4,4,4 -Heptafluoro-2-butene (CF ₃ CF = CHCF ₃ ), etc.) can be contained, so it is preferable to reduce the content of other components as much as possible.

Such a perfluoroalkadiene composition of the present disclosure includes a refrigerant for forming a state-of-the-art fine structure such as a semiconductor or a liquid crystal, as in the case of the above-mentioned perfluoroalkadiene compound alone. , Heat transfer medium, foaming agent, resin monomer, etc. can be effectively used for various purposes.

Although the embodiments of the present disclosure have been described above, various changes in the forms and details are possible without departing from the spirit and scope of the claims.

Examples are shown below to clarify the features of the present disclosure. The present disclosure is not limited to these examples.

Example _{1: ClCF 2 -CFCl-CF 2} -CF 2 I; prior to addition; no iodine-containing inorganic material
200g of zinc xylene and 34.93g (0.53mol) of (0.53 mol) was added to a condenser with eggplant flask cooled trap was connected to -78 ° C., further raw material of _{92g (0.24mol) (ClCF 2 CFClCF} 2 CF ₂ I) was added, and the mixture was heated with stirring until the internal temperature reached 140 ° C. After the internal temperature becomes constant, N, N-dimethylformamide (DMF) is added dropwise at a dropping rate of 0.53 mol / hour (1 mol / hour for 1 mol of zinc) while refluxing, and the mixture is added dropwise for 3 hours with stirring. Heating reflux was continued. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 46 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 0.35 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 1.7 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 26 mol%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 26 mol%.

Example _{2: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; no iodine-containing inorganic material
200 g (0.53 mol) of xylene and 34.93 g (0.53 mol) of zinc were added to an eggplant flask with a condenser to which a trap cooled to -78 ° C was connected, and the mixture was heated with stirring until the internal temperature reached 140 ° C. After the internal temperature becomes constant, N, N-dimethylformamide (DMF) is added dropwise at a dropping rate of 0.52 mol / hour (1.04 mol / hour with respect to 1 mol of zinc) while refluxing, and 0.5 with stirring. The heating reflux was continued for hours. Then added dropwise the raw material 1 hour _{(ClCF 2 -CFCl-CF 2 -CF} 2 I) the addition rate 0.24 mol / Time (0.48 mol / time for zinc 1 mole) at reflux with stirring for 3 hours The reflux was continued and the reaction was carried out. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 78 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 14 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.66 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 1.5 mol%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 5.9 mol%.

Example _{3: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; ZnI ₂ 0.18 mol%
The treatment was carried out in the same manner as in Example 2 except that 0.30 g (0.001 mol; 0.18 mol% with respect to zinc) of Zn I ₂ was contained in the solution of xylene containing zinc. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 88 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 8.2 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.051 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 0.32 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 3.4 mol%.

Example _{4: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; ZnI ₂ 0.6 mol%
The treatment was carried out in the same manner as in Example 2 except that 0.95 g (0.003 mol; 0.56 mol% with respect to zinc) of ZnI ₂ was contained in a solution of xylene containing zinc. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 91 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 6.8 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.042 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 0.18 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 2.0 mol%.

Example _{5: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; ZnI ₂ 1.6 mol%
The treatment was carried out in the same manner as in Example 2 except that 2.70 g (0.53 mol; 1.6 mol% with respect to zinc) of ZnI ₂ was contained in a solution of xylene containing zinc. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 93 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 5.6 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.082 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 0.27 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 1.0 mol%.

Example _{6: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; I ₂ 1.6 mol%
The treatment was carried out in the same manner as in Example 2 except that 2.20 g (0.009 mol; 1.6 mol% with respect to zinc) of I ₂ was contained in the solution of xylene containing zinc. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 96 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 2.6 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.031 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 0.17 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 1.2 mol%.

Example _{7: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; NaI 1.6 mol%
The treatment was carried out in the same manner as in Example 2 except that 1.27 g (0.0085 mol; 1.6 mol% with respect to zinc) of NaI was contained in the solution of xylene containing zinc. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 91 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 6.1 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.053 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 0.32 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 2.5 mol%.

Example _{8: ClCF 2 -CFCl-CF 2} -CF 2 I; post-addition; NaI 3.2 mol%
The treatment was carried out in the same manner as in Example 2 except that 2.54 g (0.017 mol; 3.2 mol% with respect to zinc) of NaI was contained in the solution of xylene containing zinc. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 94 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 5.1 mol%, ClCF ₂ -CFCl-CF = CF ₂ is 0.044 mol%, ClCF _2- CFCl-CF ₂ -CF ₂ H 0.12 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) is totaled 0.74 mole%.

Example _{9: ICF 2 -CF2-CF 2} -CF 2 I; prior to addition; instead _{ClCF 2 -CFCl-CF 2 -CF 2} I as no iodine containing inorganic material substrate _{ICF 2 -CF2-CF 2 -CF 2} I The treatment was carried out in the same manner as in Example 1 except that was used. After completion of the reaction, the gas phase of the collecting cylinder, the liquid phase and the reaction solution was analyzed by gas chromatography tomato graph I over, was calculated taking into account the conversion and selectivity, respectively, the conversion was 100 mol%, The selectivity of each component is 35 mol% for CF ₂ = CFCF = CF _2, 10 mol% for CF ₂ = CF-CF ₂ -CF ₂ H, and 4.2 mol for HCF ₂ -CF ₂ -CF ₂ -CF ₂ H. %, ICF ₂ -CF ₂ -CF ₂ -CF ₂ H was 30 mol%, and other by-products (CF ₃ CF = CHCF ₃ etc.) were 21 mol% in total.

Example _{10: ICF 2 -CF2-CF 2} -CF 2 I; post-addition; instead _{ClCF 2 -CFCl-CF 2 -CF 2} I as no iodine containing inorganic material substrate _{ICF 2 -CF2-CF 2 -CF 2} I The treatment was carried out in the same manner as in Example 2 except that was used. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 63 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 25 mol%, HCF ₂ -CF ₂ -CF ₂ -CF ₂ H is 2.2 mol%, _{ICF 2 -CF 2 -CF 2 -CF 2} H 2.1 mol%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 7.7 mol%.

Example _{11: ICF 2 -CF2-CF 2} -CF 2 I; post-addition; ZnI ₂ 1.6 mol%
As substrate using the _{ClCF 2 -CFCl-CF 2 -CF 2} I rather _{ICF 2 -CF2-CF 2 -CF 2} I, in a solution of xylene containing zinc, 2.70 g (0.53 mol; with respect to zinc 1.6 The treatment was carried out in the same manner as in Example 2 except that Zn I _{2 (} mol%) was included. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 87 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 5.4 mol%, HCF ₂ -CF ₂ -CF ₂ -CF ₂ H is 2.2 mol%, _{ICF 2 -CF 2 -CF 2 -CF 2} H 2.1 mol%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 3.3 mol%.

Example _{12: BrCF 2 -CF2-CF 2} -CF 2 Br; prior to addition; instead _{ClCF 2 -CFCl-CF 2 -CF 2} I as no iodine containing inorganic material substrate _{BrCF 2 -CF2-CF 2 -CF 2} Br The treatment was carried out in the same manner as in Example 1 except that was used. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 49 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 1.2 mol%, HCF ₂ -CF ₂ -CF ₂ -CF ₂ H is 3.8 mol%, _{BrCF 2 -CF 2 -CF 2 -CF 2} H 25 mol%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 21 mol%.

Example _{13: BrCF 2 -CF2-CF 2} -CF 2 Br; post-addition; instead _{ClCF 2 -CFCl-CF 2 -CF 2} I as no iodine containing inorganic material substrate _{BrCF 2 -CF2-CF 2 -CF 2} Br The treatment was carried out in the same manner as in Example 2 except that was used. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 76 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 13 mol%, HCF ₂ -CF ₂ -CF ₂ -CF ₂ H is 1.9 mol%, _{BrCF 2 -CF 2 -CF 2 -CF 2} H 2.1 mol%, and other by-products (CF ₃ CF = CHCF _3, etc.) totaled 7.0 mol%.

Example _{14: BrCF 2 -CF2-CF 2} -CF 2 Br; post-addition; ZnI ₂ 1.6 mol%
As substrate using the _{ClCF 2 -CFCl-CF 2 -CF 2} I rather _{BrCF 2 -CF2-CF 2 -CF 2} Br, in a solution of xylene containing zinc, 2.70 g (0.53 mol; with respect to zinc 1.6 The treatment was carried out in the same manner as in Example 2 except that Zn I _{2 (} mol%) was included. After completion of the reaction, the gas phase, liquid phase and reaction solution of the collected cylinder were analyzed by gas chromatography, and the conversion rate and selectivity were calculated in consideration of each. The conversion rate was 100 mol%, and each component was found. The selectivity of CF ₂ = CFCF = CF ₂ is 96 mol%, CF ₂ = CF-CF ₂ -CF ₂ H is 3.0 mol%, HCF ₂ -CF ₂ -CF ₂ -CF ₂ H is 0.51 mol%, _{BrCF 2 -CF 2 -CF 2 -CF 2} H 0.28 mole%, and other by-products (CF ₃ CF = CHCF _3, etc.) is totaled 0.21 mole%.

The results are shown in Tables 1 and 2.

Claims (8)

General formula (1):
CF ₂ = CF-(CF ₂ ) _n-4 -CF = CF ₂ (1)
[In the formula, n indicates an integer from 4 to 20. ]
It is a method for producing a perfluoroalkadiene compound represented by.
In an organic solvent, in the presence of nitrogen-containing compounds, as well as zinc or zinc alloys,
General formula (2):
CF ₂ X ¹ -CFX ^2- (CF ₂ ) _n-4 -CF ₂ -CF ₂ X ³ (2)
[In the formula, n is the same as above. X ¹ , X ² and X ³ are the same or different, X ¹ represents a chlorine atom, X ² represents a halogen atom, and X ³ represents a chlorine atom, bromine atom or iodine atom. ]
Equipped with a reaction step for reacting the compound represented by
The reaction step is a production method including a mixing step of sequentially mixing a solution containing zinc or a zinc alloy and an organic solvent, a nitrogen-containing compound, and the compound represented by the general formula (2). The mixing step includes a step of mixing a solution containing zinc or a zinc alloy and an organic solvent with a nitrogen-containing compound.
To a solution containing the zinc or zinc alloy, as well as organic solvent is added at a rate of addition of 0.1～600Mol / time the nitrogen-containing compound to the zinc or zinc alloy 1 mol method according to claim 1 .. In the mixing step, a solution containing the zinc or zinc alloy and an organic solvent is mixed with the compound represented by the general formula (2), and then the obtained mixed solution and the nitrogen-containing compound are mixed. The production method according to claim 1 or 2 . In the mixing step, a solution containing the zinc or zinc alloy and an organic solvent is mixed with the nitrogen-containing compound, and then the obtained mixed solution and the compound represented by the general formula (2) are mixed. , The manufacturing method according to claim 1 or 2 . In the mixing step, the compound represented by the general formula (2) is added to 1 mol of the zinc or zinc alloy with respect to the mixed solution of the solution containing the zinc or zinc alloy and the organic solvent and the nitrogen-containing compound. The production method according to claim 4 , wherein the zinc is added at an addition rate of 0.05 to 30 mol / hour. In the mixing step, any one of claims 1 and 2 to 5 , wherein when the solution containing the zinc or zinc alloy and the organic solvent is mixed with the nitrogen-containing compound, the solution has a temperature of 50 to 200 ° C. The manufacturing method described in the section. The production method according to any one of claims 1 to 6 , wherein the nitrogen-containing compound is N, N-dimethylformamide. The production method according to any one of claims 1 to 7 , wherein the boiling point of the organic solvent is equal to or lower than the boiling point of the nitrogen-containing compound.