JP2022141887A - Cyclobutene production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce cyclobutene comprising a halogen atom with a high conversion ratio (yield) and high selectivity.

SOLUTION: A method for producing the cyclobutene represented by general formula (1) in the figure (where X¹, X², X³ and X⁴ are the same or different and each represent a hydrogen atom, a halogen atom, or a perfluoroalkyl group; and Y represents a halogen atom) involves a step of subjecting a specific cyclobutane compound to an elimination reaction, where the elimination reaction step is performed in a closed reaction system in the presence of a base, or the elimination reaction step is performed at a reaction temperature greater than or equal to 20°C and a reaction pressure greater than or equal to 0 kPa in the presence of a base.

SELECTED DRAWING: None

COPYRIGHT: (C)2022,JPO&INPIT

Description

The present disclosure relates to methods for producing cyclobutene.

Cyclobutene containing a halogen atom is a compound useful as a dry etching gas for semiconductors, as well as various refrigerants, foaming agents, heat transfer media, and the like.

Regarding 1H-pentafluorocyclobutene among cyclobutenes containing halogen atoms, there is known a method for producing 1H-pentafluorocyclobutene from 1H,2H-hexafluorocyclobutane by dehydrofluorination reaction (for example, Non-Patent Documents 1 and 2). This technology synthesizes 1H-pentafluorocyclobutene in an open reaction system using a glass apparatus.

Buxton; Tatlow; Journal of the Chemical Society; (1954); p. Fuller, G.; Tatlow, J.C.; Journal of the Chemical Society; (1961); p.

An object of the present disclosure is to produce cyclobutene containing halogen atoms with high conversion (yield) and high selectivity.

The present disclosure includes the following configurations.

Section 1.
General formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
A method for producing cyclobutene represented by
General formula (2):

(Wherein, X ¹ , X ² , X ³ , X ⁴ and Y are the same as above; X ⁵ and X ⁶ are the same or different;
represents a hydrogen atom, a halogen atom, or a perfluoroalkyl group. )
A step of eliminating cyclobutane represented by
A production method, wherein the elimination reaction step is carried out in a closed reaction system in the presence of a base.

Section 2.
General formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
A method for producing cyclobutene represented by
General formula (2):

(Wherein, X ¹ , X ² , X ³ , X ⁴ and Y are the same as above; X ⁵ and X ⁶ are the same or different;
represents a hydrogen atom, a halogen atom, or a perfluoroalkyl group. )
A step of eliminating cyclobutane represented by
The production method, wherein the elimination reaction step is carried out at a reaction temperature of 20° C. or higher, a reaction pressure of 0 kPa or higher, and in the presence of a base.

Item 3.
3. The production method according to item 1 or ² , wherein the ^X5 is a hydrogen atom, the X6 is a halogen atom, and the elimination reaction is a dehydrohalogenation reaction.

Section 4.
General formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
A composition containing cyclobutene represented by
A composition, wherein the content of cyclobutene represented by the general formula (1) is 99 mol% or more based on the total amount of the composition being 100 mol%.

Item 5.
The content of 1H-perfluorocyclobutene ₍ 1H- _cC4F5H ) is 99 mol% or more and the content of 3H-perfluorocyclobutene ₍ 3H- _cC4F5H ) is 1 mol% or less. 5. The composition according to item 4 above.

Item 6.
6. The composition according to item 4 or 5, which is used as a cleaning gas, an etching gas, a deposit gas, or a building block for organic synthesis.

According to the present disclosure, cyclobutene containing halogen atoms can be produced with high conversion (yield) and high selectivity.

As a result of intensive research, the present inventors have found that the step of eliminating the raw material compound is carried out in the presence of a base in a closed reaction system to obtain a compound containing a halogen atom represented by the above general formula (1). It has been found that cyclobutene can be produced with high conversion (yield) and high selectivity.

The present disclosure has been completed as a result of further research based on such findings.

The present disclosure includes the following embodiments.

General formula (1) of the present disclosure:

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
The method for producing cyclobutene represented by
General formula (2):

(Wherein, X ¹ , X ² , X ³ , X ⁴ and Y are the same as above; X ⁵ and X ⁶ are the same or different;
represents a hydrogen atom, a halogen atom, or a perfluoroalkyl group. )
The step of eliminating cyclobutane represented by is included.

In the present disclosure, the elimination reaction step is performed in a closed reaction system in the presence of a base.

In the present disclosure, the elimination reaction step is performed at a reaction temperature of 20° C. or higher, a reaction pressure of 0 kPa or higher, and in the presence of a base.

In this disclosure, reaction pressures are gauge pressures unless otherwise specified.

In the present disclosure, by satisfying the above requirements, halogen atom-containing cyclobutene can be produced with high conversion (yield) and high selectivity.

In the present disclosure, the “conversion rate” refers to the molar amount of the raw material compound (cyclobutane containing a halogen atom) supplied to the reactor, and the compound other than the raw material compound contained in the outflow gas from the reactor outlet (halogen atom cyclobutene, etc.) is the ratio (mol%) of the total molar amount.

In the present disclosure, the term “selectivity” refers to the target compound contained in the outflow gas (halogen atom containing cyclobutene) means the ratio (mol%) of the total molar amount.

In the method for producing cyclobutene of the present disclosure, unlike the reaction using a glass vessel of the prior art, for example, by using a metal vessel, pressure is applied and the boiling point of the raw material is raised to increase the liquid component. , the yield of the target compound can be improved.

(1) Raw material compound In the present disclosure, the raw material compound has the general formula (2):

( ^In the ^formula , X1 ^, X2, X3, ^X4 , ^X5 and X6 are the ^same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom. )
is a cyclobutane represented by

X1, X2, X3 ^{, X4} , ^X5 and ^{X6 are} the ^same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group.

Y represents a halogen atom.

The halogen atoms of X ¹ , X ² , X ³ , X ⁴ , X ⁵ , X ⁶ and Y are fluorine atom, chlorine atom, bromine atom,
and iodine atoms.

The perfluoroalkyl groups of X ¹ , X ² , X ³ , X ⁴ , X ⁵ and X ⁶ are alkyl groups in which all hydrogen atoms are substituted with fluorine atoms. The perfluoroalkyl group is, for example, a perfluoroalkyl group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, more preferably 1 to 6 carbon atoms, still more preferably 1 to 4 carbon atoms, and particularly preferably 1 to 3 carbon atoms. A fluoroalkyl group is preferred. The perfluoroalkyl group is preferably a linear or branched perfluoroalkyl group. The perfluoroalkyl group is preferably a trifluoromethyl group (CF ₃ -) and a pentafluoroethyl group (C ₂ F ₅ -).

As a raw material compound, cyclobutane containing a halogen atom represented by general formula (2),
X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group, in that cyclobutene containing a halogen atom can be produced with high selectivity, More preferably, ^X5 is a hydrogen atom, ^X6 is a fluorine atom, and Y is a fluorine atom.

Examples of cyclobutane represented by the general formula (2), which is a raw material compound, include:

compounds such as

These cyclobutanes represented by general formula (2) can be used alone or in combination of two or more. As such cyclobutane, a known or commercially available product can be adopted.

In the halogen-containing cyclobutane represented by the general formula (2), X ¹ , X ² and X ³ can be produced with high selectivity and high conversion rate (yield). , X ⁴ and X ⁶ are fluorine atoms, X ⁵ is a hydrogen atom, and Y is more preferably a fluorine atom.

(2) Elimination Reaction In the method for producing halogen atom-containing cyclobutene according to the present disclosure, first, a solution of the raw material compound represented by the general formula (2) is prepared.

The elimination reaction step in the present disclosure is performed in a closed reaction system in the presence of a base.

^In the elimination reaction step in the present disclosure, it is preferable that ^X5 is a hydrogen atom, X6 is a halogen atom, and the elimination reaction is a dehydrohalogenation reaction. ^In the elimination reaction step in the present disclosure, it is preferable that ^X5 is a hydrogen atom, X6 is a fluorine atom, and the elimination reaction is a dehydrofluorination reaction.

For example, in cyclobutane containing a halogen atom represented by the general formula (2) as a raw material compound, X ¹ , X ² , X ³ , X ⁴ and X ⁶ are fluorine atoms, and X ⁵ is a hydrogen atom. , Y are preferably fluorine atoms.

According to the following reaction formula, the elimination reaction is preferably a dehydrofluorination reaction.

Solvent The solvent is preferably water. Examples of non-aqueous solvents include carbonate esters such as dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, methyl propyl carbonate, and ethyl propyl carbonate; ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propionic acid; Esters such as butyl, ketones such as acetone, ethyl methyl ketone, diethyl ketone, lactones such as γ-butyrolactone, γ-valerolactone, tetrahydrofuran, tetrahydropyran, diethyl ether, dibutyl ether, diisopropyl ether, 1,2- Ethers such as dimethoxyethane, 1,2-diethoxyethane, tetrahydrofuran; nitriles such as acetonitrile, propionitrile and benzonitrile; amide amides such as N,N-dimethylform; sulfones such as dimethylsulfoxide and sulfolane; is preferred. The solvent is preferably at least one selected from the group consisting of water and non-aqueous solvents.

Base In this step, it is preferable to use an alkali as a base.

The alkali used in this step is preferably an alkali metal or alkaline earth metal hydroxide, more preferably sodium hydroxide or potassium hydroxide. In this step, an aqueous solution of alkali metal or alkaline earth metal hydroxide is preferred, and an aqueous solution of sodium hydroxide or potassium hydroxide is more particularly preferred. By using the alkali, the target compound can be obtained with higher selectivity and higher conversion.

The content of hydroxides of alkali metals or alkaline earth metals in the reaction solution, preferably in the aqueous solution, is not particularly limited, but is preferably 20 to 60% by mass with respect to the entire reaction solution.
It is more preferably ~55% by mass. By setting the alkali content in the reaction solution within the above range, the target compound can be obtained with higher selectivity and higher conversion.

Moreover, in this step, an organic alkoxide can be preferably used as the base. As the organic alkoxide, for example, methoxypotassium, ethoxypotassium, t-butoxypotassium and the like can be preferably used.

Catalyst In this step, a catalyst can be used as necessary. The catalyst used in this step is preferably a hydrocarbon-based alkoxide. Hydrocarbon alkoxides include tetramethylammonium fluoride, tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, tetraethylammonium fluoride, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and tetrapropylammonium. fluoride, tetrapropylammonium chloride, tetrapropylammonium bromide, tetrapropylammonium iodide, tetrabutylammonium fluoride, tetrabutylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium iodide, benzyltriethylammonium fluoride, benzyltriethylammonium Chloride, Benzyltriethylammonium bromide, Benzyltriethylammonium iodide, Benzyltributylammonium fluoride, Benzyltributylammonium chloride, Benzyltributylammonium bromide, Benzyltributylammonium iodide, Methyltributylammonium fluoride, Methyltributylammonium chloride, Methyltributylammonium bromide , methyltributylammonium iodide, methyltrioctylammonium fluoride, methyltrioctylammonium chloride (trademark Aliquat 336), methyltrioctylammonium bromide, and methyltrioctylammonium iodide. . By using the above catalyst, the target compound can be obtained with higher selectivity and higher conversion.

Closed Reaction System The elimination reaction step in the present disclosure is characterized by being carried out in the presence of the base in a closed reaction system.

Cyclobutene containing a halogen atom represented by the general formula (1) of the target compound of the present disclosure has a low boiling point and exists as a gas at room temperature. Therefore, in the step of carrying out the elimination reaction in the present disclosure, by making the reaction system a closed reaction system, the pressure in the closed reaction system naturally rises, and the reaction is carried out under pressurized conditions.

Since the boiling point of the target compound is thus low, the closed reaction system is pressurized, and the concentration of the substrate (raw material compound) in the reaction solution (base solution) increases to improve the reactivity. In the closed reaction system, it is preferable to perform the reaction by sealing the reaction system using a batch-type pressure-resistant reaction vessel. In the case of batch reaction, for example, a pressure vessel such as an autoclave is charged with a raw material compound, a base solution (aqueous alkaline solution), a catalyst, etc., heated to an appropriate reaction temperature with a heater, and stirred for a certain period of time. It is preferred to react. As the reaction atmosphere, it is preferable to carry out the reaction in an atmosphere of an inert gas such as nitrogen, helium, or carbon dioxide gas.

In the elimination reaction step of the present disclosure, the lower limit of the reaction temperature in the closed pressure reaction system is such that the elimination reaction proceeds more efficiently and the target compound can be obtained with higher selectivity. From the viewpoint of suppressing a decrease in the temperature, the temperature is usually 20°C, preferably 25°C, more preferably 30°C, and still more preferably 40°C.

In the elimination reaction step of the present disclosure, the upper limit of the reaction temperature in the closed reaction system is from the viewpoint that the dehydrofluorination reaction can proceed more efficiently and the target compound can be obtained with higher selectivity, and From the viewpoint of suppressing a decrease in selectivity due to decomposition or polymerization of reaction products, the temperature is usually 50°C, preferably 45°C.

In the elimination reaction step of the present disclosure, the target compound can be obtained with higher selectivity and higher conversion by performing the reaction in a closed reaction system.

Pressurized Reaction System The elimination reaction step in the present disclosure is characterized in that the reaction temperature is set to 20° C. or higher, the reaction pressure is set to 0 kPa or higher, and the reaction is performed in the presence of the base.

When the reaction system is pressurized in this manner, the substrate (raw material compound) concentration in the reaction solution (basic solution, alkaline aqueous solution) increases, and reactivity can be improved. In the pressurized reaction system, it is preferable to carry out the reaction by sealing the reaction system using a batch-type pressure-resistant reaction vessel. In the case of batch reaction, for example, a pressure vessel such as an autoclave is charged with a raw material compound, a base solution (aqueous alkaline solution), a catalyst, etc., heated to an appropriate reaction temperature with a heater, and stirred for a certain period of time. It is preferred to react.

In the desorption reaction step of the present disclosure, the pressurization condition is a reaction pressure of 0 kPa or higher.

The reaction pressure is the internal pressure of the reaction vessel used in the pressurized reaction system. In the elimination reaction step of the present disclosure, the reaction is preferably carried out under a reaction pressure of preferably 0 kPa or higher, more preferably 10 kPa or higher, still more preferably 20 kPa or higher, and particularly preferably 30 kPa or higher.

In the elimination reaction step of the present disclosure, the pressurization condition is an absolute pressure of preferably 101.3 kPa or higher, more preferably 111.3 kPa or higher, still more preferably 121.3 kPa or higher, and particularly preferably 131.3 kPa or higher. It is preferable to let

For pressurization, an inert gas such as nitrogen, helium, or carbon dioxide gas is fed into the reaction system, thereby increasing the pressure in the reaction system.

In the elimination reaction step of the present disclosure, the lower limit of the reaction temperature in the pressurized reaction system is such that the elimination reaction proceeds more efficiently and the target compound can be obtained with higher selectivity. From the viewpoint of suppressing a decrease in the temperature, the temperature is usually 20°C, preferably 25°C, more preferably 30°C, and still more preferably 40°C.

In addition, in the step of performing the desorption reaction in the present disclosure, as pressurization conditions, in order to adjust the reaction pressure to 0 kPa or more, or to adjust the absolute pressure to 101.3 kPa or more, the lower limit of the reaction temperature in the pressurized reaction system The value is usually 20°C. Thus, in the step of performing the desorption reaction in the present disclosure, it is preferable to heat and pressurize the inside of the reaction vessel to carry out the desorption reaction.

In the elimination reaction step of the present disclosure, the upper limit of the reaction temperature in the pressurized reaction system is from the viewpoint that the dehydrofluorination reaction can proceed more efficiently and the target compound can be obtained with higher selectivity. In addition, from the viewpoint of suppressing a decrease in selectivity due to decomposition or polymerization of reaction products, the temperature is usually 50°C, preferably 45°C.

In the elimination reaction step of the present disclosure, the target compound can be obtained with higher selectivity and higher conversion by performing the reaction in a pressurized reaction system.

After completion of the elimination reaction, the cyclobutene containing a halogen atom represented by the general formula (1) can be obtained by performing a purification treatment according to a conventional method, if necessary.

Combination of Closed Reaction System and Pressurized Reaction System In the desorption reaction step in the present disclosure, liquid It may be carried out in a continuous and pressurized reaction mode while gasifying and extracting the substance.

(3) Target compound The target compound in the present disclosure has the general formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
is a cyclobutene containing a halogen atom represented by

X ¹ , X ² , X ³ and X ⁴ and Y are the same as above.

The cyclobutene represented by the general formula (1) to be produced is, for example, the following

compounds such as

In cyclobutene containing a halogen atom represented by general formula (1), X ¹ , X ² , X ³ and X ⁴ are
It is the same or different and represents a hydrogen atom, a halogen atom or a perfluoroalkyl group, and Y is preferably a fluorine atom. In the halogen atom-containing cyclobutene represented by formula (1), X ¹ , X ² , X ³ and X ⁴ are more preferably fluorine atoms, and Y is more preferably a fluorine atom.

In the method for producing cyclobutene containing a halogen atom in the present disclosure, the starting compound is cyclobutane containing a halogen atom represented by general formula (2), and X ¹ , X ² , X ³ , X ⁴ and X ⁶ are
It is preferable that the elimination reaction is a fluorine atom, X ⁵ is a hydrogen atom, and Y is a fluorine atom.

According to the following reaction formula, the elimination reaction is preferably a dehydrofluorination reaction.

It is preferable that the objective compound is a cyclobutene containing a halogen atom represented by the general formula (1), X ¹ , X ² , X ³ and X ⁴ are fluorine atoms, and Y is a fluorine atom.

(4) Composition Containing Halogen Atom-Containing Cyclobutene As described above, a halogen atom-containing cyclobutene represented by general formula (1) can be obtained. It may be obtained in the form of a composition containing cyclobutene containing a halogen atom represented by general formula (2) and cyclobutane containing a halogen atom represented by general formula (2).

As cyclobutene containing a halogen atom represented by general formula (1) contained in the composition, X ¹
, X ² , X ³ and X ⁴ are fluorine atoms, and Y is preferably a fluorine atom.

In the composition containing cyclobutene containing a halogen atom represented by general formula (1) of the present disclosure, the content of cyclobutene containing a halogen atom represented by general formula (1), with the total amount of the composition being 100 mol% is preferably 99 mol % or more.

In the composition containing cyclobutene containing a halogen atom represented by general formula (1) of the present disclosure, the content of cyclobutene containing a halogen atom represented by general formula (1), with the total amount of the composition being 100 mol% is preferably 1 mol% to 99.9 mol%, more preferably 5 mol% to 99.9 mol%, even more preferably 10 mol% to 99.9 mol%.

In the method for producing cyclobutene containing a halogen atom according to the present disclosure, the following compounds may be produced as impurities in the elimination reaction.

In the composition containing cyclobutene containing a halogen atom represented by general formula (1) of the present disclosure, 1H-perfluorocyclobutene ₍ 1H- _cC4F5H ) is contained with respect to the total amount of 100 mol% of the composition The amount is 99 mol % or more, and the content of 3H-perfluorocyclobutene (3H-cC ₄ F ₅ H) is preferably 1 mol % or less.

According to the production method of the present disclosure, even if it is obtained as a composition containing a cyclobutene containing a halogen atom represented by the general formula (1), it contains a halogen atom represented by the general formula (1) Cyclobutene can be obtained with a particularly high selectivity, and as a result, it is possible to reduce components other than cyclobutene containing a halogen atom represented by general formula (1) in the composition. According to the production method of the present disclosure, it is possible to reduce labor for refining to obtain cyclobutene containing a halogen atom represented by general formula (1).

The composition containing the halogen atom-containing cyclobutene represented by the general formula (1) of the present disclosure is the most suitable for semiconductors, liquid crystals, etc., as in the case of the halogen atom-containing cyclobutene alone represented by the general formula (1). In addition to etching gas for forming a fine structure at the tip, it can be effectively used for various purposes such as deposit gas, building block for organic synthesis, cleaning gas, and the like.

The deposit gas is a gas that deposits an etch-resistant polymer layer.

The building block for organic synthesis means a substance that can be a precursor of a compound having a highly reactive skeleton. For example, when a cyclobutene containing a halogen atom represented by the general formula (1) of the present disclosure or a composition containing the same is reacted with a fluorine-containing organosilicon compound such as CF ₃ Si(CH ₃ ) ₃ , CF ₃ It is possible to introduce a fluoroalkyl group such as a group into a substance that can be used as a detergent or a fluorine-containing pharmaceutical intermediate.

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

EXAMPLES The present disclosure will be specifically described below with reference to Examples, but the present disclosure is not limited by these Examples.

<Example>
In the method for producing cyclobutene containing a halogen atom in the example, the raw material compound has the general formula (2
), X ¹ , X ² , X ³ , X ⁴ and X ⁶ are fluorine atoms, X ⁵ is a hydrogen atom, and Y is a fluorine atom.

According to the following reaction formula, the desorption reaction was a dehydrofluorination reaction.

The target compound is a cyclobutene containing a halogen atom represented by the general formula (1), wherein X ¹
, X ² , X ³ and X ⁴ are fluorine atoms, and Y is a fluorine atom.

In addition, the following compounds may be produced as impurities in the elimination reaction.

An autoclave (200 cc) was used as an example reaction system.

By using an autoclave as a reaction system, this reaction system can be (a) a closed reaction system in the presence of a base (alkali), or (b) a reaction temperature of 20 ° C. or higher and a reaction pressure of 0 kPa or higher. , represents a pressurized reaction system carried out in the presence of a base (alkali). Pressurizing in this way involves sealing.

Example 1
Into the autoclave, a 50 wt% KOH aqueous solution was added as a reaction solution, the raw material compound (cC ₄ F ₆ H ₂ ) was added, the lid was closed to make a closed system, and then nitrogen was forced into the autoclave. The pressure at that time was 20 kPa. After that, the mixture was stirred at room temperature (25°C) to allow the reaction to proceed. After starting the dehydrofluorination reaction, sampling was performed as appropriate, and the reaction was completed when there was no change in the composition in the reaction system. The pressure at the end of the reaction was 80 kPa.

After stirring is stopped, the mixture is cooled to 0°C and subjected to mass spectrometry by gas chromatography/mass spectrometry (GC/MS) using gas chromatography (manufactured by Shimadzu Corporation, trade name "GC-2014"), and NMR ( Structural analysis was performed by NMR spectrum using JEOL, trade name "400YH").

The results of mass spectrometry and structural analysis confirmed that cC ₄ F ₅ H was produced as the target compound. _In Example 1, the conversion from _{cC4F6H2 (} starting compound) was 92.1 mol%, and the selectivity (yield) of _{cC4F5H (} target compound) was 97.8 mol%.

Example 2
Following the experimental method of Example 1, methyltrioctylammonium chloride (trademark Aliquat 336) was used as a catalyst to initiate the dehydrofluorination reaction. Dehydrofluorination reaction, mass spectrometry and structural analysis were carried out in the same manner as in Example 1 except for the above conditions.

The results of mass spectrometry and structural analysis confirmed that cC ₄ F ₅ H was produced as the target compound. _In Example ₂ , the conversion from _cC4F6H2 (starting compound) was 93.2 mol%, and the selectivity for _{cC4F5H (} target compound) was 98.9 mol%.

Example 3
Following the experimental method of Example 1, a 50 wt % KOH dibutyl ether solution obtained by adding KOH (alkali) as a base to dibutyl ether (reaction solvent) was used as the reaction solution to initiate the dehydrofluorination reaction. Dehydrofluorination reaction, mass spectrometry and structural analysis were carried out in the same manner as in Example 1 except for the above conditions.

The results of mass spectrometry and structural analysis confirmed that cC ₄ F ₅ H was produced as the target compound. In Example ₃ , the conversion from _{cC4F6H2 (} starting compound) was 93.4 mol%, and the selectivity for _{cC4F5H (} target compound) was 98.5 mol%.

Example 4
Following the experimental method of Example 1, a dibutyl ether solution obtained by adding tert-butoxykapotassium (t-BuOK) (1.2 equivalents) as a base to dibutyl ether (reaction solvent) was used as the reaction solution, and defluoridation was performed. A hydrogen reaction was initiated. Dehydrofluorination reaction, mass spectrometry and structural analysis were carried out in the same manner as in Example 1 except for the above conditions.

The results of mass spectrometry and structural analysis confirmed that cC ₄ F ₅ H was produced as the target compound. In Example ₃ , the conversion from _{cC4F6H2 (} starting compound) was 95.4 mol%, and the selectivity for _{cC4F5H (} target compound) was 98.9 mol%.

Comparative example 1
Comparative Example 1 was an open reaction system. 50 wt% KOH was added to a flask (200 cc) and equipped with a dry ice condenser and a dropping funnel. Add the raw material compound (cC ₄ F ₆ H ₂ ) to the dropping funnel,
Drip was performed. After that, stirring was performed at room temperature. After starting the dehydrofluorination reaction, sampling was performed as appropriate, and the reaction was completed when there was no change in the composition in the reaction system. The reaction was in an open system, and the pressure was always 0 kPa.

After stopping stirring, the mixture was cooled to 0°C. The results of mass spectrometry and structural analysis confirmed that cC ₄ F ₅ H was produced as the target compound. In Example ₃ , the conversion from _{cC4F6H2 (} starting compound) was 51.7 mol%, and the selectivity for _{cC4F5H (} target compound) was 97.1 mol%.

Claims (6)

General formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
A method for producing cyclobutene represented by
General formula (2):

(Wherein, X ¹ , X ² , X ³ , X ⁴ and Y are the same as above; X ⁵ and X ⁶ are the same or different;
represents a hydrogen atom, a halogen atom, or a perfluoroalkyl group. )
A step of eliminating cyclobutane represented by
A production method, wherein the elimination reaction step is carried out in the presence of a base in a closed reaction system. General formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
A method for producing cyclobutene represented by
General formula (2):

(Wherein, X ¹ , X ² , X ³ , X ⁴ and Y are the same as above; X ⁵ and X ⁶ are the same or different;
represents a hydrogen atom, a halogen atom, or a perfluoroalkyl group. )
A step of eliminating cyclobutane represented by
The production method, wherein the elimination reaction step is carried out at a reaction temperature of 20° C. or higher, a reaction pressure of 0 kPa or higher, and in the presence of a base. 3. The production method according to claim ¹ , wherein said ^X5 is a hydrogen atom, said X6 is a halogen atom, and said elimination reaction is a dehydrohalogenation reaction. General formula (1):

(Wherein, X ¹ , X ² , X ³ and X ⁴ are the same or different and represent a hydrogen atom, a halogen atom or a perfluoroalkyl group. Y represents a halogen atom.)
A composition containing cyclobutene represented by
A composition, wherein the content of cyclobutene represented by the general formula (1) is 99 mol% or more based on the total amount of the composition being 100 mol%. The content of 1H-perfluorocyclobutene ₍ 1H- _cC4F5H ) is 99 mol% or more and the content of 3H-perfluorocyclobutene ₍ 3H- _cC4F5H ) is 1 mol% or less. 5. The composition of claim 4. 6. A composition according to claim 4 or 5, used as cleaning gas, etching gas, depositing gas or building block for organic synthesis.