Method for producing monofluoroalkane

Abstract

The objective is to provide a method to obtain monofluoroalkanes industrially at a low cost, with high yield and high selectivity. As a method for manufacturing monofluoroalkanes, At least one fluoride selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, and The following general formula (1): (In the formula, R is the same or different and represents an alkyl group having 1 to 10 carbon atoms, and X represents Cl, Br, or I.) A manufacturing method is provided comprising a process for obtaining the monofluoroalkane by reacting a tetraalkylammonium salt represented by .

Description

Technology Field

[0001] The present disclosure relates to a method for producing monofluoroalkanes. Background Technology

[0002] As a method for preparing monofluoroalkanes such as CH3F, a method is known in which tetrabutylammonium is prepared from tetrabutylammonium cyanide (TBACN) and hexafluorobenzene, and methyl iodide is reacted (see, for example, Non-patent Literature 1). Prior art literature

[0003] Journal of American Chemical Society, 2005, 127 (7), pp 2050-2051. The problem to be solved

[0004] The present disclosure aims to provide a method for obtaining monofluoroalkanes at a high yield and high selectivity at an industrially low cost. means of solving the problem

[0005] The present disclosure includes the following configurations.

[0006] Claim 1. As a method for producing a monofluoroalkane,

[0007] At least one fluoride selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, and

[0008] The following general formula (1):

[0009]

[0010] (In the formula, R is the same or different and represents an alkyl group having 1 to 10 carbon atoms, and X represents Cl, Br, or I.)

[0011] A process of obtaining the monofluoroalkane by reacting a tetraalkylammonium salt represented by

[0012] A manufacturing method comprising

[0013] Claim 2. The manufacturing method described in Claim 1, wherein R is the same or different and is an alkyl group having 1 to 4 carbon atoms.

[0014] Claim 3. A manufacturing method described in Claim 1 or 2, wherein the reaction temperature in the above process is 50 to 250°C.

[0015] Claim 4. A manufacturing method described in any one of Claims 1 to 3, wherein the molar ratio of the tetraalkylammonium salt to the fluoride in the above process is 1:0.1 to 1:10.

[0016] Claim 5. A manufacturing method described in any one of Claims 1 to 4, wherein the above process is carried out in a solvent containing a nitrogen-containing compound.

[0017] Claim 6. The method of preparation described in Claim 5, wherein the solvent comprises at least one selected from the group consisting of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylpropyleneurea, and pyridine.

[0018] Paragraph 7. The following general formula (2):

[0019] RF (2)

[0020] (In the formula, R represents an alkyl group having 1 to 10 carbon atoms.)

[0021] Monofluoroalkanes represented by, and,

[0022] A composition containing an alkene having 1 to 10 carbon atoms.

[0023] Claim 8. A composition described in Claim 7, wherein the content of the monofluoroalkane is 90 mol% or more, with the sum of the moles of the monofluoroalkane and the alkene being 100 mol%.

[0024] Claim 9. A composition described in Claim 7 or 8, used as a cleaning gas, etching gas, synthetic raw material, or synthetic intermediate. Effects of the invention

[0025] According to the present disclosure, monofluoroalkanes can be obtained industrially at a low cost with high yield and high selectivity. Specific details for implementing the invention

[0026] In this specification, the term "contains" encompasses "comprise," "consist essentially of," and "consist of." Additionally, in this specification, when a numerical range is denoted as "A to B," it means A or greater and B or less.

[0027] In the present disclosure, "selection rate" means the ratio (mol%) of the total molar amount of the target compound included in the gas after the reaction to the total molar amount of compounds other than the source compound in the gas after the reaction.

[0028] In the present disclosure, "conversion rate" means the ratio (mol%) of the total molar amount of compounds other than the raw material compound contained in the gas after reaction to the molar amount of the raw material compound supplied to the reactor.

[0029] In the present disclosure, "yield" means the ratio (mol%) of the total molar amount of the target compound contained in the gas after reaction to the molar amount of the raw material compound supplied to the reactor.

[0030] 1. Method for preparing monofluoroalkanes

[0031] The method for producing a monofluoroalkane of the present disclosure comprises at least one fluoride selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, and

[0032] The following general formula (1):

[0033]

[0034] (In the formula, R is the same or different and represents an alkyl group having 1 to 10 carbon atoms, and X represents Cl, Br, or I.)

[0035] A process for obtaining the monofluoroalkane is provided by reacting a tetraalkylammonium salt represented by .

[0036] Conventionally, as a method for producing monofluoroalkanes such as CH3F, for example, a method of preparing tetrabutylammonium from tetrabutylammonium cyanide (TBACN) and hexafluorobenzene and reacting it with methyl iodide has been employed. This method is not suitable for industrial use because it takes time to prepare TBAF within the system and TBACN, hexafluorobenzene, and hexacyanobenzene are generated as waste, and a new method is desired to obtain monofluoroalkanes with high yield and high selectivity.

[0037] According to the present disclosure, as described above, by reacting at least one fluoride selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides with a specific tetraalkylammonium salt, monofluoroalkanes can be obtained industrially at a low cost with high conversion rate and high selectivity.

[0038] (1-1) Tetraalkylammonium salt

[0039] The tetraalkylammonium salt that can be used as a raw material compound in the manufacturing method of the present disclosure is the following general formula (1)

[0040]

[0041] It is a tetraalkylammonium salt represented by (wherein R is the same or different and represents an alkyl group having 1 to 10 carbon atoms, and X represents Cl, Br, or I).

[0042] The above R is the same or different and is an alkyl group having 1 to 10 carbon atoms. From the perspective of obtaining monofluoroalkanes more industrially and more cheaply with a higher conversion rate and high selectivity, the number of carbon atoms of R is preferably 1 to 8, more preferably 2 to 6, and even more preferably 3 to 4.

[0043] In general formula (1), the alkyl group represented by R may include, for example, a methyl group; an ethyl group; a propyl group such as an n-propyl group or an i-propyl group; a butyl group such as an n-butyl group, an i-butyl group, a sec-butyl group, or a t-butyl group; or a pentyl group such as an n-pentyl group, an i-pentyl group, a sec-pentyl group, a t-pentyl group, or a neopentyl group. Among these, methyl, ethyl, n-propyl, and n-butyl groups are preferred, and methyl and ethyl groups are more preferred, from the perspective of obtaining monofluoroalkanes more cheaply industrially and with higher conversion rates and higher selectivity.

[0044] In general formula (1), X is a chlorine atom, a bromine atom, or an iodine atom. Among these, a chlorine atom or a bromine atom is preferred from the perspective of being able to obtain monofluoroalkanes more cheaply industrially and with a higher conversion rate and higher selectivity.

[0045] As for the raw material compound tetraalkylammonium salt, from the perspective of obtaining monofluoroalkanes more industrially and more cheaply with higher conversion and higher selectivity, it is preferable to have a tetraalkylammonium salt in which R is an alkyl group having 1 to 4 carbon atoms and X is a chlorine atom or a bromine atom.

[0046] As a tetraalkylammonium salt as a raw material compound satisfying the above conditions, specifically,

[0047]

[0048] Examples include the above. These tetraalkylammonium salts may be used individually or in combination of two or more types. Such tetraalkylammonium salts may be known or commercially available products.

[0049] (1-2) Fluoride

[0050] The process for obtaining a monofluoroalkane in the present disclosure involves reacting at least one fluoride selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides with the tetraalkylammonium salt. The fluoride functions as a fluorine source and can produce the monofluoroalkane with particularly high conversion, yield, and selectivity.

[0051] As for the alkali metal fluoride, although not particularly limited, alkali metal fluorides of the 4th to 7th periods are preferred in terms of the ability to produce monofluoroalkanes with particularly high conversion, yield, and selectivity, and, for example, potassium fluoride (KF), cesium fluoride (CsF), etc. are more preferred.

[0052] As for alkaline earth metal fluorides, they are not particularly limited, but from the perspective of being able to produce monofluoroalkanes with particularly high conversion, yield, and selectivity, fluorides of alkaline earth metals of the 4th to 7th periods are preferred, and for example, calcium fluoride (CaF2), magnesium fluoride (MgF2), etc. are more preferred.

[0053] The above fluoride may be used alone or in combination of two or more types.

[0054] (1-3) Molar ratio of tetraalkylammonium salts and fluorides

[0055] In the above process, the molar ratio of the tetraalkylammonium salt to the fluoride is preferably 1:0.1 to 1:10, and more preferably 1:0.5 to 1:5. By having the molar ratio within the above range, the yield and selectivity of the monofluoroalkane are further improved.

[0056] (1-4) Solvent

[0057] The process in the present disclosure is preferably a process of reacting a tetraalkylammonium salt with a fluoride in a solvent. By reacting a tetraalkylammonium salt with a fluoride in a solvent, the yield and selectivity of monofluoroalkanes are further improved.

[0058] The solvent is not particularly limited and, for example, may be a solvent containing a nitrogen-containing compound. Examples of such nitrogen-containing compounds include N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylpropyleneurea, pyridine, etc. Among these, N-methylpyrrolidone, N,N-dimethylformamide, and pyridine are preferred, and N-methylpyrrolidone is more preferred. These nitrogen-containing compounds may be used alone or in combination of two or more types.

[0059] The concentration of tetraalkylammonium salt in the solvent is not particularly limited, but 0.01 to 10 mol / L is preferred and 0.05 to 5 mol / L is more preferred from the view that monofluoroalkanes can be produced with particularly high conversion rate, yield, and selectivity.

[0060] The concentration of fluoride in the solvent is not particularly limited, but 0.01 to 10 mol / L is preferred and 0.05 to 5 mol / L is more preferred from the perspective of being able to produce monofluoroalkanes with particularly high conversion rate, yield and selectivity.

[0061] (1-5) Reaction temperature

[0062] In the process of obtaining a monofluoroalkane by reacting a fluoride with a tetraalkylammonium salt represented by the general formula (1) in the present disclosure, the reaction temperature is typically 50 to 300°C, more preferably 50 to 250°C, and even more preferably 80 to 220°C, from the view that the monofluoroalkane can be produced with particularly high conversion rate, yield, and selectivity.

[0063] (1-6) Reaction time

[0064] In the case where the process of the present disclosure is a process of reacting a tetraalkylammonium salt with a fluoride in a solvent, the reaction time is preferably 0.1 hr to 48 hr and more preferably 1 hr to 24 hr from the view that the conversion rate of the reaction is particularly high and monofluoroalkane can be obtained with a higher yield and higher selectivity.

[0065] (1-7) Reaction pressure

[0066] In the present disclosure, the reaction pressure in the above process is preferably -0.05 to 2 MPa, more preferably -0.01 to 1 MPa, and even more preferably atmospheric pressure to 0.5 MPa, from the view that monofluoroalkanes can be produced with particularly high conversion, yield, and selectivity. Additionally, in the present disclosure, unless otherwise specifically indicated, the pressure shall be gauge pressure.

[0067] In the reaction of the present disclosure, the shape and structure of the reactor for reacting the fluoride and, if necessary, the gas containing fluorine with the raw material compound (tetraalkylammonium salt) is not particularly limited, as long as it can withstand the above temperature and pressure. Examples of reactors include a vertical reactor, a horizontal reactor, a multi-tube reactor, etc. Examples of reactor materials include glass, stainless steel, iron, nickel, iron-nickel alloy, etc.

[0068] (1-8) Examples of reactions

[0069] The process for obtaining monofluoroalkane according to the present disclosure can be carried out by either a batch type in which a solvent, a raw material compound (tetraalkylammonium salt), and a fluoride are injected into a reactor and reacted, or a continuous stirring type reactor in which a raw material compound (tetraalkylammonium salt) is continuously injected into a reactor and a target compound (monofluoroalkane) is continuously drawn from the reactor.

[0070] Regarding the atmosphere used when performing the process of obtaining monofluoroalkane according to the present disclosure, an inert gas atmosphere is preferred in order to suppress the deterioration of the fluoride. Examples of such inert gases include nitrogen, helium, and argon. Among these inert gases, nitrogen is preferred in terms of reducing costs. The concentration of the inert gas is preferably 0 to 50 mol% of the gas component introduced into the reactor.

[0071] After the reaction is finished, purification treatment can be performed according to conventional methods as needed to obtain monofluoroalkanes.

[0072] (1-9) Target Compound

[0073] The target compound of the present disclosure obtained in this way is a monofluoroalkane having an alkyl group having 1 to 10 carbon atoms, for example, general formula (2):

[0074] RF (2)

[0075] (In the formula, R represents an alkyl group having 1 to 10 carbon atoms.)

[0076] Examples include monofluoroalkanes represented by .

[0077] In general formula (2), R is an alkyl group having 1 to 10 carbon atoms. The number of carbon atoms of R is preferably 1 to 8, more preferably 1 to 6, and even more preferably 1 to 4.

[0078] In general formula (2), the alkyl group represented by R may include, for example, a methyl group; an ethyl group; a propyl group such as an n-propyl group or an i-propyl group; a butyl group such as an n-butyl group, an i-butyl group, a sec-butyl group, or a t-butyl group; or a pentyl group such as an n-pentyl group, an i-pentyl group, a sec-pentyl group, a t-pentyl group, or a neopentyl group. Among these, methyl, ethyl, n-propyl, and n-butyl groups are preferred, and methyl and ethyl groups are more preferred, from the perspective of obtaining monofluoroalkanes more cheaply industrially and with higher conversion rates and higher selectivity.

[0079] In addition, the above R is the same as the R in the above general formula (1).

[0080] The monofluoroalkane obtained by the present disclosure can be effectively used for various purposes, such as etching gas, cleaning gas, synthetic raw material, or synthetic intermediate, for forming state-of-the-art microstructures such as semiconductors and liquid crystals.

[0081] 2. Composition

[0082] As described above, monofluoroalkanes can be obtained, and in some cases, they are obtained in the form of a composition containing monofluoroalkanes.

[0083] As such a composition, for example, general formula (2):

[0084] RF (2)

[0085] (In the formula, R represents an alkyl group having 1 to 10 carbon atoms.)

[0086] Examples of compositions containing monofluoroalkanes represented by can be given.

[0087] In this case, with the total amount of the composition of the present disclosure set to 100 mol%, the lower limit of the content of the monofluoroalkane represented by general formula (2) is preferably 90.0 mol% or more, and more preferably 95 mol% or more. In addition, the upper limit of the content of the monofluoroalkane is preferably higher, and may be 100 mol% or less, 99.8 mol% or less, 99.0 mol% or less, etc.

[0088] Additionally, this composition may include an alkene having 1 to 10 carbon atoms. The number of carbon atoms of the alkene is the same as the number of carbon atoms of R of the monofluoroalkane represented by the general formula (2) included in the composition of the present disclosure. For example, if the monofluoroalkane represented by the general formula (2) is CH3CH2F, the alkene is ethylene. Also, if the monofluoroalkane represented by the general formula (2) is CH3CH2CH2CH2F, the alkene is butene.

[0089] In this case, with the total amount of the composition of the present disclosure set to 100 mol%, the upper limit of the content of the alkene having 1 to 10 carbon atoms is preferably 10.0 mol% or less, and more preferably 5.0 mol% or less. In addition, the lower limit of the content of the alkene having 1 to 10 carbon atoms is preferably lower, and may be 0 mol% or more, 0.2 mol% or more, 1.0 mol% or more, etc.

[0090] In addition, according to the manufacturing method of the present disclosure, even when obtained as the above-described composition, the monofluoroalkane represented by general formula (2) can be obtained industrially at a low cost with a high conversion rate of the reaction, a high yield, and a high selectivity. Therefore, it is possible to reduce the components other than the monofluoroalkane represented by general formula (2) in the composition, and thus reduce the cost and energy associated with purification to obtain the monofluoroalkane represented by general formula (2).

[0091] The composition of the present disclosure can be effectively used for various purposes, such as etching gases and cleaning gases, for forming state-of-the-art microstructures such as semiconductors and liquid crystals.

[0092] Although embodiments of the present disclosure have been described above, various changes in form or detail are possible without departing from the spirit and scope of the claims.

[0093] Examples

[0094] Examples are provided below to clarify the features of the present disclosure. The present disclosure is not limited to these examples.

[0095] Examples 1-5

[0096] 5 mL of N-methylpyrrolidone was added to an autoclave as a solvent. Then, the tetraalkylammonium salt shown in Table 1 and KF as a fluoride were added in a molar ratio of 1:1, and the lid was closed. Subsequently, the reaction was carried out by heating at the temperature shown in Table 1 for 24 hours.

[0097] After the reaction was completed, the generated gas was washed with water. Subsequently, mass analysis was performed by gas chromatography / mass spectrometry (GC / MS) using gas chromatography (manufactured by Shimadzu Corporation, product name "GC-2014"), and structural analysis was performed using NMR spectra using NMR (manufactured by JEOL, product name "400YH").

[0098] From the results of mass spectrometry and structural analysis, it was confirmed that a monofluoroalkane was produced as the target compound.

[0099] In addition, the residual amount of KF was measured by ion chromatography, and the conversion rate was calculated by calculating the number of moles of the residual amount of KF relative to the number of moles of injected KF. The results are shown in Table 1.

[0100] [Table 1]

[0101]

Claims

Claim 1 As a composition, at least one fluoride selected from the group consisting of alkali metal fluorides and alkaline earth metal fluorides, and the following general formula (1): A composition comprising a monofluoroalkane prepared by a method for preparing monofluoroalkane comprising a process of reacting a tetraalkylammonium salt represented by (wherein R is the same or different and represents an alkyl group having 1 to 10 carbon atoms, and X represents Cl, Br, or I) to obtain the monofluoroalkane, and a monofluoroalkane represented by the following general formula (2): RF (2) (wherein R represents an alkyl group having 1 to 10 carbon atoms), and an alken having 1 to 10 carbon atoms. Claim 2 A composition according to claim 1, wherein R is the same or different and is an alkyl group having 1 to 4 carbon atoms. Claim 3 A composition according to claim 1 or claim 2, wherein the reaction temperature in the process is 50 to 250°C. Claim 4 A composition according to claim 1 or claim 2, wherein the molar ratio of the tetraalkylammonium salt to the fluoride in the process is 1:0.1 to 1:

10. Claim 5 A composition according to claim 1 or claim 2, wherein the process is carried out in a solvent containing a nitrogen-containing compound. Claim 6 A composition according to claim 5, wherein the solvent comprises at least one selected from the group consisting of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, N,N-dimethylpropyleneurea, and pyridine. Claim 7 A composition according to claim 1 or claim 2, wherein the content of the monofluoroalkane is 90 mol% or more, with the sum of the moles of the monofluoroalkane and the alkene being 100 mol%. Claim 8 A composition according to claim 1 or claim 2, used as a cleaning gas, etching gas, synthetic raw material, or synthetic intermediate.

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