Method for producing trifluoroacetone acyl fluoride dimer and perfluoro (2,4-dimethyl-2-fluoroformyl-1,3-dioxolane)

Abstract

The present invention provides a method for producing a trifluoroacetoneyl fluoride dimer, which comprises a reaction step of reacting hexafluoropropylene oxide with aldehydes.

Description

Technical Field

[0001] The present invention relates to a method for preparing an aldehyde adduct of hexafluoropropylene oxide, a trifluoroacetone acyl fluoride dimer and a method for preparing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane). Background Art

[0002] Patent Document 1 describes a method for producing a trifluoroacetoneyl fluoride dimer in which benzophenone and hexafluoropropylene oxide are reacted in an autoclave at 185° C. for 4 hours.

[0003] Patent Document 2 discloses a method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) by reacting hexafluoropropylene oxide with trifluoroacetone fluoride as a raw material in the presence of cesium fluoride in a solvent of diethylene glycol dimethyl ether.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: British Patent No. 1051647

[0007] Patent Document 2: U.S. Patent No. 3308107 Summary of the invention

[0008] In Patent Document 1, as a method for producing trifluoroacetone acyl fluoride (i.e., monomer), a method implemented in a circulation system under normal pressure is described. The boiling point of trifluoroacetone acyl fluoride is 9° C. to 10° C., which is relatively low. It is difficult to carry out industrial processing, while the boiling point of trifluoroacetone acyl fluoride dimer is 72° C., so it is easy to handle. However, in the method for producing trifluoroacetone acyl fluoride dimer described in Patent Document 1, the pressure rises to 4MPa to 5MPa, so a device suitable for high-pressure reaction is necessary.

[0009] In view of the above, one embodiment of the present invention provides a method for producing a trifluoroacetoneyl fluoride dimer that can be carried out under mild conditions.

[0010] Another embodiment of the present invention provides a method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) in good yield using the trifluoroacetoneyl fluoride dimer synthesized by the above-mentioned production method as a raw material.

[0011] The present inventors have conducted intensive research on the method for producing trifluoroacetoneyl fluoride dimer, and have newly discovered that by using aldehydes instead of benzophenone used in the production method described in Patent Document 1, an aldehyde adduct obtained by adding aldehydes to hexafluoropropylene oxide can be prepared, and by further reacting, trifluoroacetoneyl fluoride dimer can be produced under mild conditions.

[0012] Furthermore, the present inventors have newly found that perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) can be produced in good yield using the trifluoroacetoneyl fluoride dimer obtained by the above method as a raw material.

[0013] That is, the present invention is as follows.

[0014] [1] A method for producing a trifluoroacetone acyl fluoride dimer, the method comprising:

[0015] A reaction step of reacting hexafluoropropylene oxide with aldehydes.

[0016] [2] The method for producing a trifluoroacetone fluoride dimer according to [1], wherein

[0017] In the reaction step, hexafluoropropylene oxide and aldehydes are reacted at 0°C to 100°C.

[0018] [3] The method for producing a trifluoroacetone fluoride dimer according to [1] or [2], wherein

[0019] After the reaction step, there is an aging step of aging at 100° C. or higher.

[0020] [4] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [3], wherein

[0021] After the reaction step, there is an aging step of aging at 100°C to 150°C.

[0022] [5] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [4], wherein

[0023] Aldehydes are aldehydes which have no hydrogen atom in the α-position of the carbonyl group.

[0024] [6] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [5], wherein

[0025] Aldehydes are aromatic aldehydes.

[0026] [7] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [6], wherein

[0027] Aldehydes are aromatic aldehydes substituted with electron donating groups.

[0028] [8] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [7], wherein

[0029] Aldehydes are electron-donating group-substituted benzaldehydes.

[0030] [9] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [8], wherein

[0031] The aldehyde is 4-methoxybenzaldehyde.

[0032]

[10] The method for producing a trifluoroacetone fluoride dimer according to any one of [1] to [9], wherein

[0033] The reaction process was carried out at 3.5 MPa or less.

[0034]

[11] An aldehyde adduct obtained by adding aldehyde to hexafluoropropylene oxide, which is prepared by reacting hexafluoropropylene oxide with aldehydes.

[0035]

[12] An aldehyde adduct, which is at least one selected from the group consisting of an aldehyde adduct represented by the following formula 1, an aldehyde adduct represented by the following formula 2, and an aldehyde adduct represented by the following formula 3,

[0036] Formula 1

[0037]

[0038] Formula 2

[0039]

[0040] Formula 3

[0041]

[0042] In the formula, R represents a substituted or unsubstituted alkyl group or aryl group.

[0043]

[13] A method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane), the method comprising:

[0044] A dimer synthesis step of synthesizing a trifluoroacetone fluoride dimer by the method described in any one of [1] to

[10] ; and

[0045] A dimer reaction step is performed to react the synthesized trifluoroacetone acyl fluoride dimer.

[0046]

[14] The method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) according to

[13] , wherein

[0047] The dimer reaction step is a step of reacting the trifluoroacetoneyl fluoride dimer with hexafluoropropylene oxide in an organic solvent in the presence of a fluoride.

[0048]

[15] The method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) according to

[13] or

[14] , wherein

[0049] After the dimer reaction step, there is an isomerization step.

[0050]

[16] The method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) according to any one of

[13] to

[15] , wherein

[0051] The dimer reaction step is performed on the two layers of the reaction solution separated into two layers by the method of any one of [1] to

[10] .

[0052] According to one embodiment of the present invention, there can be provided an industrial method for producing a trifluoroacetoneyl fluoride dimer that can be carried out using a general-purpose machine.

[0053] According to one embodiment of the present invention, there is provided a method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) in good yield using the trifluoroacetoneyl fluoride dimer obtained by the above method as a raw material. DETAILED DESCRIPTION

[0054] A method for producing a trifluoroacetoneyl fluoride dimer according to one embodiment of the present invention (hereinafter also simply referred to as “production method”) includes a reaction step of reacting hexafluoropropylene oxide with aldehydes.

[0055] Hereinafter, the above-mentioned production method (hereinafter also simply referred to as "dimer production method" or "dimer synthesis step") is described in more detail.

[0056] [Method for producing dimer (dimer synthesis step)]

[0057] The dimer production method described above uses aldehydes instead of benzophenone used in the production method described in Patent Document 1. As a result, the production method described in Patent Document 1 can be carried out at a lower pressure than that in the production method described in Patent Document 1.

[0058] In one embodiment of the above production method, hexafluoropropylene oxide and aldehydes may be temporarily reacted at 0°C to 100°C, preferably 0°C to 99°C, more preferably 0°C to 90°C to generate an aldehyde adduct of hexafluoropropylene oxide, and then reacted at 100°C or higher, preferably 100°C to 200°C, more preferably 100°C to 150°C. The above method may be implemented, for example, at a pressure of 1 MPa or less. In addition, trifluoroacetone fluoride dimers may be produced at a high yield.

[0059] In more detail, in the above-mentioned production method, hexafluoropropylene oxide and aldehydes can be added to a pressure-resistant container below room temperature, first reacted at 0°C to 100°C, preferably at 0°C to 99°C, more preferably at 0°C to 90°C for 0.5 hours to 12.0 hours, and after generating an aldehyde adduct to hexafluoropropylene oxide, the temperature is then raised to above 100°C, preferably 100°C to 200°C, more preferably 100°C to 150°C, and reacted for 5 hours to 48 hours. It should be noted that the reaction time can be shortened or extended as needed. In addition, room temperature refers to a temperature in the range of, for example, 20°C to 25°C. That is, in the above-mentioned reaction step in the above-mentioned production method, hexafluoropropylene oxide and aldehydes are preferably reacted at 0°C to 100°C, preferably at 0°C to 99°C, more preferably at 0°C to 90°C for 0.5 hours to 12.0 hours. The production method preferably comprises an aging step of reacting at 100°C or higher, preferably 100°C to 200°C, more preferably 100°C to 150°C for 5 to 48 hours after the reaction step. It should be noted that the temperature described in this specification is the liquid temperature of the reaction solution unless otherwise specified.

[0060] In the reaction step of reacting hexafluoropropylene oxide with aldehydes, aldehydes may be added to a pressure vessel in advance, and hexafluoropropylene oxide may be continuously or intermittently supplied at a temperature of 0° C. to 100° C. for 0.5 to 24 hours to carry out the reaction.

[0061] Examples of the trifluoroacetone fluoride dimer include 4-fluoro-5-oxo-2,4-bis(trifluoromethyl)-1,3-dioxolane-2-carbonyl fluoride. 4-fluoro-5-oxo-2,4-bis(trifluoromethyl)-1,3-dioxolane-2-carbonyl fluoride can be represented by the following formula A.

[0062] [Compound 4]

[0063] Formula A

[0064]

[0065] Aldehydes refer to one or more aldehydes. Specific examples of the aldehydes include propionaldehyde, butyraldehyde, valeraldehyde, isovaleraldehyde, pivalaldehyde, 1-adamantanecarboxaldehyde, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, 2-ethylbenzaldehyde, 3-ethylbenzaldehyde, 4-ethylbenzaldehyde, 2-methoxybenzaldehyde, 3-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2-ethoxybenzaldehyde, 3-ethoxybenzaldehyde, 4-ethoxybenzaldehyde, 2-fluorobenzaldehyde, 3-fluorobenzaldehyde, 4-fluorobenzaldehyde, 2-chlorobenzaldehyde, 3-chlorobenzaldehyde, 4-chlorobenzaldehyde, 2-bromobenzaldehyde, 3-bromobenzaldehyde, 4-bromobenzaldehyde, 1-naphthaldehyde, 5-methoxy-1-naphthaldehyde, 5-chloro-1-naphthaldehyde, 2-naphthaldehyde, 5-methoxy-2-naphthaldehyde, and 5-chloro-2-naphthaldehyde. As preferred aldehydes, benzaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, 2-ethylbenzaldehyde, 3-ethylbenzaldehyde, 4-ethylbenzaldehyde, 2-methoxybenzaldehyde, 3-methoxybenzaldehyde, 4-methoxybenzaldehyde, 2-ethoxybenzaldehyde, 3-ethoxybenzaldehyde, 4-ethoxybenzaldehyde, etc. can be cited. Aldehydes are preferably used in an amount of 0.8 to 1.2 mol relative to the hexafluoropropylene oxide supplied to the reaction. From the viewpoint of the yield of trifluoroacetone acyl fluoride dimer, aldehydes that do not have a hydrogen atom at the α-position of the carbonyl group are preferred. In addition, from the same viewpoint, it is preferred to use aromatic aldehydes as aldehydes, more preferably to use electron-donating group-substituted aromatic aldehydes, and further preferably to use electron-donating group-substituted benzaldehydes.

[0066] The above reaction step can be carried out without solvent, or one of solvents such as toluene, ethylbenzene, xylene, mesitylene, cumene, anisole, chlorobenzene, etc. can be used alone or two or more of them can be mixed in any ratio. When a solvent is used, the amount thereof can be set in the range of 0.1 to 5.0 times by mass relative to the hexafluoropropylene oxide supplied to the reaction.

[0067] The reaction step is preferably carried out in a pressure-resistant container at a pressure of 3.5 MPa or less, more preferably 1.2 MPa or less. The pressure is the internal pressure of the container.

[0068] In the above reaction step, hexafluoropropylene oxide is reacted with aldehydes, but an aldehyde adduct to hexafluoropropylene oxide obtained in the reaction is also one embodiment of the present invention.

[0069] The aldehyde adduct can be obtained by adding aldehydes to hexafluoropropylene oxide to obtain a cyclized or linear structure. Such an aldehyde adduct can be represented by the following formula 1, formula 2 or formula 3.

[0070] [Compound 5]

[0071] Formula 1

[0072]

[0073] [Compound 6]

[0074] Formula 2

[0075]

[0076] [Compound 7]

[0077] Formula 3

[0078]

[0079] In the above formulae 1 to 3, R represents a substituted or unsubstituted alkyl group or an aryl group.

[0080] [Method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane)]

[0081] <Dimerization reaction step>

[0082] The trifluoroacetoneyl fluoride dimer can be derived into perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) through a dimer reaction step according to the description of US Pat. No. 3,308,107 and an isomerization step which is preferably performed.

[0083] In the dimer reaction step, trifluoroacetoneyl fluoride dimer can be reacted with hexafluoropropylene oxide in an organic solvent in the presence of a fluoride.

[0084] In one embodiment, the reaction solution obtained by the dimer production method is cooled to about -20°C to 30°C as needed to obtain a reaction solution separated into two layers, an upper layer and a lower layer, and a layer containing a mixture of by-products (e.g., difluoromethyl compounds, i.e., fluorides of aldehydes, etc.) and / or a solvent (usually becoming the upper layer) is separated and removed from the reaction solution, or the trifluoroacetone fluoride dimer is purified by distillation or the like as needed, and then a dimer reaction step is performed.

[0085] In addition, in one embodiment, the dimer reaction process can be implemented to the above-mentioned upper layer and lower layer. Thus, compared with the case where the dimer reaction process is implemented only to the layer that can mainly contain trifluoroacetone acyl fluoride dimers, that is, the lower layer, the yield of perfluoro (2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) can be improved. That is, the results of the in-depth study by the present inventors have newly found that: by carrying out the above-mentioned dimer manufacturing method and dimer reaction process in a so-called one pot mode, without the process of separating the target substance and the by-product in the above-mentioned dimer manufacturing method, the yield of perfluoro (2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) can be improved. The dimer reaction process can be carried out by taking out a part of the upper layer and a part of the lower layer simultaneously or separately from the reaction liquid separated into the upper layer and the lower layer obtained by the above-mentioned dimer production method, or the dimer reaction process can be carried out directly or after stirring and mixing the reaction liquid separated into the upper layer and the lower layer obtained by the above-mentioned dimer production method.

[0086] As an organic solvent for the dimer reaction process, as long as it is a solvent that is inactive to the reaction, there is no particular limitation. As an organic solvent, for example: aromatic solvents such as toluene, ethylbenzene, xylene, mesitylene, ether solvents such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether can be cited. One organic solvent can be used alone, or two or more can be mixed and used in any proportion. As an organic solvent, from the viewpoint of the solubility of fluoride, it is preferred to use one of ether solvents such as ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether alone or two or more can be mixed and used in any proportion. The amount of the organic solvent used for the reaction is not particularly limited, and it can usually be used in an amount of 0.3 to 5.0 times the mass relative to the synthetic raw materials provided for the reaction.

[0087] As long as the fluoride used in the dimer reaction process is a fluoride, there is no particular limitation. Specifically, examples include: alkali metal fluorides such as lithium fluoride, sodium fluoride, potassium fluoride, cesium fluoride, beryllium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, and other alkaline earth metal fluorides, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, tetra-n-butylammonium fluoride, phenyltrimethylammonium fluoride, and other organic ammonium fluorides. From the viewpoint of solubility and reactivity in organic solvents, the fluoride is preferably selected from one or more of sodium fluoride, potassium fluoride, cesium fluoride, tetramethylammonium fluoride, tetraethylammonium fluoride, tetrapropylammonium fluoride, and tetra-n-butylammonium fluoride. Fluoride can be used alone, or two or more can be mixed and used in any proportion. Relative to the trifluoroacetone acyl fluoride dimer provided for the reaction, the amount of the fluoride used for the reaction can be set to, for example, a range of 0.05 mole times to 1.00 mole times. When added in too small a quantity, the reaction is slow, and use in large quantities is not economical, and therefore, it is preferably used in an amount of 0.1 to 0.8 mol times.

[0088] The amount of hexafluoropropylene oxide used in the dimer reaction step is preferably 2.00 times or more, more preferably 2.05 to 2.50 times, based on the trifluoroacetone fluoride dimer.

[0089] In the dimer reaction step, the order of adding the various components provided for the reaction is not particularly limited. It is preferred to prepare a layer (usually the lower layer) mainly composed of trifluoroacetone fluoride dimer, or a mixture of the upper and lower layers, a fluoride and an organic solvent of the reaction solution obtained by the above-mentioned dimer production method, and add hexafluoropropylene oxide to the mixture. For example, a mixture of the upper and lower layers of the reaction solution obtained by the above-mentioned dimer production method, a fluoride and an organic solvent is prepared, the mixture is adjusted to a temperature in the range of -20°C to 60°C, and hexafluoropropylene oxide is added over 0.5 hours to 48 hours. After the addition of hexafluoropropylene oxide, in order to complete the production of perfluoro(3,5-dimethyl-2-oxo-1,4-dioxolane) as the target in the dimer reaction step, that is, as an intermediate for the production of perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) The dimer reaction step can be preferably carried out in a pressure-resistant container.

[0090] <Isomerization process>

[0091] After the dimerization step, an isomerization step is preferably performed. The isomerization step is to convert perfluoro(3,5-dimethyl-2-oxo-1,4-difluoro) The step of isomerizing 2,4-dimethyl-2-fluoroformyl-1,3-dioxolane to perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane). Perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) is represented by the following formula 4 and can be obtained as a mixture of diastereomers.

[0092] [Compound 8]

[0093] Formula 4

[0094]

[0095] In the isomerization step, the reaction solution after the dimer reaction step can be heated at 100° C. to 150° C. for 4 to 48 hours to perform the isomerization reaction, and then the isomerization is terminated. The isomerization step is preferably performed in a pressure-resistant container. The pressure in the container for performing the isomerization step is preferably set to a range of 0.1 MPa to 1.0 MPa.

[0096] After the isomerization step, for example, the mixture is cooled to room temperature and depressurized, followed by filtration and separation and removal of the upper organic solvent layer, thereby obtaining the target perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane).

[0097] The obtained perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) is hydrolyzed according to Macromolecules 2005, 38, 4237-4245 to prepare potassium salt, and then decarbonated to derive perfluoro(2-methylene-4-methyl-1,3-dioxolane). By polymerizing perfluoro(2-methylene-4-methyl-1,3-dioxolane), poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)] can be obtained. Poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)] is a polymer that is expected to be used as a resin for gas separation membranes, a transparent resin for optical fibers, and the like.

[0098] Example

[0099] Hereinafter, the present invention will be further described by way of examples. However, the present invention is not limited to the embodiments shown in the examples.

[0100] In the following analysis, the following machines were used.

[0101] 19 F-NMR: AVANCE II 400 manufactured by BRUKER

[0102] GC: GC-2025 (FID) manufactured by Shimadzu Corporation

[0103] GC-MS: GCMS-QP2010 (EI) manufactured by Shimadzu Corporation

[0104] [Example 1]

[0105] Preparation of trifluoroacetone acyl fluoride dimer

[0106] Butyraldehyde (1.37 kg, 19.00 mol) was added to a 10 L SUS316 autoclave equipped with a stirrer and having a pressure resistance of 8 MPa, and after cooling to 0°C on an ice bath, hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added thereto.

[0107] Next, the autoclave was sealed and heated to 60°C while stirring for 5 hours. At this time, the maximum pressure reached 0.9 MPa, and the pressure dropped to 0.06 MPa after 5 hours. The temperature was further raised to 140°C and maintained at the same temperature for 8 hours. At this time, the maximum pressure reached 0.7 MPa, and the pressure dropped to 0.2 MPa after 8 hours.

[0108] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a light yellow transparent liquid (2.46 kg). 19 F-NMR analysis confirmed that the product was only trifluoropyruvic acid dimer. 19 In the quantitative analysis of F-NMR, 1.98 kg (6.87 mol) of the target trifluoropyruvic acid dimer was generated (yield 72% / butyraldehyde basis). The dimer was obtained as a mixture of two diastereomers at a ratio of 1 / 1 (molar ratio).

[0109] 19 F-NMR (neat, 376 MHz) (isomer 1) δ 22.40, -81.43, -81.82, -122.92, (isomer 2) δ 22.30, -81.69, -81.82, -122.10.

[0110] [Example 2]

[0111] Preparation of trifluoroacetone acyl fluoride dimer

[0112] Using the same reaction apparatus as in Example 1, valeraldehyde (1.63 kg, 18.92 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), and hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added, and the mixture was kept at 70° C. for 3 hours, and then reacted at 130° C. for 24 hours. It should be noted that the maximum pressures at 70° C. and 130° C. were 0.9 MPa and 0.6 MPa, respectively.

[0113] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.34 kg). 19 In the quantitative analysis of F-NMR, 1.98 kg (6.87 mol) of the target trifluoropyruvic acid dimer was generated (yield 73% / valeraldehyde basis).

[0114] [Example 3]

[0115] Preparation of trifluoroacetone acyl fluoride dimer

[0116] Using the same reaction apparatus as in Example 1, pivalaldehyde (1.63 kg, 18.92 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), and hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added, and the mixture was kept at 90° C. for 12 hours, and then reacted at 140° C. for 36 hours. It should be noted that the maximum pressures at 90° C. and 140° C. were 0.9 MPa and 0.7 MPa, respectively.

[0117] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.45 kg). 19 In the quantitative analysis of F-NMR, 2.13 kg (7.39 mol) of the target trifluoropyruvic acid dimer was generated (yield 78% / based on pivalaldehyde).

[0118] [Example 4]

[0119] Preparation of trifluoroacetone acyl fluoride dimer

[0120] Using the same reaction apparatus as in Example 1, benzaldehyde (2.01 kg, 18.94 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), and hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added, and the mixture was kept at 60° C. for 5 hours, and then reacted at 130° C. for 8 hours. It should be noted that the maximum pressures at 60° C. and 130° C. were 0.7 MPa and 0.8 MPa, respectively.

[0121] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.56 kg). 19 In the quantitative analysis of F-NMR, 2.18 kg (7.57 mol) of the target trifluoropyruvic acid dimer was generated (yield 80% / benzaldehyde basis).

[0122] [Example 5]

[0123] Preparation of trifluoroacetone acyl fluoride dimer

[0124] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added, and the reaction was carried out at 50°C for 3 hours.

[0125] A portion of the obtained reaction solution was extracted, separated by a common method, and subjected to qualitative analysis, whereby it was confirmed that a plurality of aldehyde adducts were generated by adding aldehydes to hexafluoropropylene oxide. The structures of the confirmed aldehyde adducts 1 to 3 are shown below.

[0126] [Compound 9]

[0127] (aldehyde adduct 1)

[0128] 2,3,3,3-Tetrafluoro-2-[fluoro-(4-methoxyphenyl)-methoxy]-propionyl fluoride

[0129]

[0130] 1 H-NMR (400MHz, CDCl3) δ3.79(3H), 6.68(1H), 6.93(2H), 7.40(2H).

[0131] 19 F-NMR (376MHz, CDCl3) δ25.45, -82.60, -117.90, -136.07.

[0132] GC-MS (m / z): 302 (M + ), 139, 96, 69.

[0133] [Compound 10]

[0134] (Aldehyde adduct 2)

[0135] 1,1,1,3,3-Pentafluoro-3-[fluoro-(4-methoxyphenyl)-methoxy]-propan-2-one

[0136]

[0137] 1 H-NMR (400MHz, CDCl3) δ3.79(3H), 6.38(1H), 6.93(2H), 7.40(2H).

[0138] 19F-NMR (376MHz, CDCl3) δ-80.38, -83.53, -90.50, -120.04.

[0139] GC-MS (m / z): 302 (M + ), 139, 96, 69.

[0140] [Compound 11]

[0141] (Aldehyde adduct 3)

[0142] 4,4,5-Trifluoro-2-(4-methoxyphenyl)-5-trifluoromethyl-[1,3]dioxolane

[0143]

[0144] 1 H-NMR (400MHz, CDCl3) δ3.79(3H), 6.51(1H), 6.93(2H), 7.40(2H).

[0145] 19 F-NMR (376MHz, CDCl3) δ-79.65, -80.76, -86.38, -131.90.

[0146] GC-MS (m / z): 302 (M + ), 283, 271, 233, 167, 135, 120.

[0147] Then, the autoclave was sealed and reacted for 8 hours at 140° C. The maximum pressures at 50° C. and 140° C. were 0.8 MPa and 0.6 MPa, respectively.

[0148] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.30 kg). 19 In the quantitative analysis of F-NMR, 2.15 kg (7.46 mol) of the target trifluoropyruvic acid dimer was generated (yield 85% / based on 4-methoxybenzaldehyde).

[0149] [Example 6]

[0150] Preparation of trifluoroacetone acyl fluoride dimer

[0151] Using the same reaction apparatus as in Example 1, 4-methylbenzaldehyde (2.10 kg, 17.48 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), and hexafluoropropylene oxide (2.91 kg, 17.53 mol) was added, and the mixture was kept at 70° C. for 3 hours, and then reacted at 130° C. for 6 hours. It should be noted that the maximum pressures at 70° C. and 130° C. were 0.9 MPa and 0.7 MPa, respectively.

[0152] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.24 kg). 19 In the quantitative analysis of F-NMR, 2.09 kg (7.26 mol) of the target trifluoropyruvic acid dimer was generated (yield 83% / based on 4-methylbenzaldehyde).

[0153] [Example 7]

[0154] Preparation of trifluoroacetone acyl fluoride dimer

[0155] The same reaction apparatus as in Example 1 was used, 2-methoxybenzaldehyde (2.38 kg, 17.48 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), hexafluoropropylene oxide (3.48 kg, 20.96 mol) was added, and the mixture was kept at 70° C. for 6 hours, and then reacted at 150° C. for 6 hours. It should be noted that the maximum pressures at 70° C. and 150° C. were 0.8 MPa and 0.6 MPa, respectively.

[0156] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.20 kg). 19 In the quantitative analysis of F-NMR, 2.04 kg (7.08 mol) of the target trifluoropyruvic acid dimer was generated (yield 81% / based on 2-methoxybenzaldehyde).

[0157] [Example 8]

[0158] Preparation of trifluoroacetone acyl fluoride dimer

[0159] Using the same reaction apparatus as in Example 1, 2-methylbenzaldehyde (2.10 kg, 17.48 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), and hexafluoropropylene oxide (2.91 kg, 17.53 mol) was added, and the mixture was kept at 70° C. for 5 hours, and then reacted at 140° C. for 12 hours. It should be noted that the maximum pressures at 70° C. and 140° C. were 0.9 MPa and 0.6 MPa, respectively.

[0160] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.23 kg). 19 In the quantitative analysis of F-NMR, 2.02 kg (7.01 mol) of the target trifluoropyruvic acid dimer was generated (yield 80% / based on 2-methylbenzaldehyde).

[0161] [Example 9]

[0162] Preparation of trifluoroacetone acyl fluoride dimer

[0163] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol), hexafluoropropylene oxide (3.15 kg, 18.97 mol) and anisole (2.0 kg, 18.49 mol) were added, and the reaction was carried out at 50° C. for 10 hours, and then at 140° C. for 24 hours. It should be noted that the maximum pressures at 50° C. and 140° C. were 0.6 MPa and 0.4 MPa, respectively.

[0164] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.03 kg). 19 In the quantitative analysis of F-NMR, 1.84 kg (6.39 mol) of the target trifluoropyruvic acid dimer was generated (yield 73% / based on 4-methoxybenzaldehyde).

[0165] [Example 10]

[0166] Preparation of trifluoroacetone acyl fluoride dimer

[0167] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol), hexafluoropropylene oxide (3.15 kg, 18.97 mol) and toluene (2.50 kg, 27.13 mol) were added, and the reaction was carried out at 60° C. for 8 hours, and then at 140° C. for 30 hours. It should be noted that the maximum pressures at 60° C. and 140° C. were 0.4 MPa and 0.6 MPa, respectively.

[0168] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.06 kg). 19 In the quantitative analysis of F-NMR, 1.92 kg (6.67 mol) of the target trifluoropyruvic acid dimer was generated (yield 76% / based on 4-methoxybenzaldehyde).

[0169] [Example 11]

[0170] Preparation of trifluoroacetone acyl fluoride dimer

[0171] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol), hexafluoropropylene oxide (3.15 kg, 18.97 mol) and mesitylene (1.4 kg, 11.65 mol) were added, and the reaction was carried out at 50° C. for 6 hours, and then at 140° C. for 18 hours. It should be noted that the maximum pressures at 50° C. and 140° C. were 0.7 MPa and 0.5 MPa, respectively.

[0172] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.00 kg). 19 In the quantitative analysis of F-NMR, 1.77 kg (6.14 mol) of the target trifluoropyruvic acid dimer was generated (yield 70% / based on 4-methoxybenzaldehyde).

[0173] [Example 12]

[0174] Preparation of trifluoroacetone acyl fluoride dimer

[0175] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol), hexafluoropropylene oxide (3.15 kg, 18.97 mol) and chlorobenzene (0.6 kg, 5.33 mol) were added, and the reaction was carried out at 60° C. for 5 hours and then at 140° C. for 10 hours. It should be noted that the maximum pressures at 60° C. and 140° C. were 0.5 MPa and 0.6 MPa, respectively.

[0176] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 1.98 kg). 19 In the quantitative analysis of F-NMR, 1.71 kg (5.94 mol) of the target trifluoropyruvic acid dimer was generated (yield 68% / based on 4-methoxybenzaldehyde).

[0177] [Example 13]

[0178] Preparation of trifluoroacetone acyl fluoride dimer

[0179] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (1.19 kg, 8.74 mol), hexafluoropropylene oxide (1.58 kg, 9.52 mol) and anisole (4.0 kg, 36.99 mol) were added, and the reaction was carried out at 70° C. for 12 hours, and then at 140° C. for 48 hours. It should be noted that the maximum pressures at 70° C. and 140° C. were 0.7 MPa and 0.7 MPa, respectively.

[0180] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 1.09 kg). 19 In the quantitative analysis of F-NMR, 0.93 kg (3.23 mol) of the target trifluoropyruvic acid dimer was generated (yield 74% / based on 4-methoxybenzaldehyde).

[0181] [Example 14]

[0182] Preparation of trifluoroacetone acyl fluoride dimer

[0183] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol) and hexafluoropropylene oxide (3.15 kg, 18.97 mol) were added and reacted at 140° C. for 12 hours. The maximum pressure during this period was 1.7 MPa.

[0184] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 1.98 kg). 19 In the quantitative analysis of F-NMR, 1.81 kg (6.28 mol) of the target trifluoropyruvic acid dimer was generated (yield 72% / based on 4-methoxybenzaldehyde).

[0185] [Example 15]

[0186] Preparation of trifluoroacetone acyl fluoride dimer

[0187] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol) was added and heated to 85°C. Hexafluoropropylene oxide (3.15 kg, 18.97 mol) was continuously supplied for 7 hours while maintaining the same temperature, and the reaction process was carried out. The maximum pressure during this period was 0.2 MPa. Next, the reaction temperature was set to 140°C and the reaction was carried out for 12 hours. The maximum pressure at 140°C was 0.7 MPa.

[0188] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.35 kg). 19 In the quantitative analysis of F-NMR, 2.17 kg (7.53 mol) of the target trifluoropyruvic acid dimer was generated (yield 86% / based on 4-methoxybenzaldehyde).

[0189] [Example 16]

[0190] Preparation of trifluoroacetone acyl fluoride dimer

[0191] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol) and toluene (2.50 kg, 27.13 mol) were added, heated to 85°C, and then hexafluoropropylene oxide (3.15 kg, 18.97 mol) was continuously supplied for 8 hours while maintaining the same temperature, and the reaction process was carried out. The maximum pressure during this period was 0.2 MPa. Next, the reaction temperature was set to 140°C and the reaction was carried out for 30 hours. The maximum pressure at 140°C was 0.6 MPa.

[0192] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.21 kg). 19 In the quantitative analysis of F-NMR, 1.94 kg (6.73 mol) of the target trifluoropyruvic acid dimer was generated (yield 77% / based on 4-methoxybenzaldehyde).

[0193] [Example 17]

[0194] Preparation of trifluoroacetone acyl fluoride dimer

[0195] Using the same reaction apparatus as in Example 1, 4-methoxybenzaldehyde (2.38 kg, 17.48 mol) was used instead of butyraldehyde (1.37 kg, 19.00 mol), and hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added, and the reaction was carried out at 50° C. for 3 hours, and then at 180° C. for 2 hours. It should be noted that the maximum pressures at 50° C. and 180° C. were 0.8 MPa and 1.9 MPa, respectively.

[0196] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.34 kg). 19In the quantitative analysis of F-NMR, 2.11 kg (7.33 mol) of the target trifluoropyruvic acid dimer was generated (yield 84% / based on 4-methoxybenzaldehyde).

[0197] [Example 18]

[0198] Preparation of Perfluoro(2,4-Dimethyl-2-fluoroformyl-1,3-dioxolane)

[0199] The trifluoropyruvic acid dimer prepared in Example 1 (123.18 g, pure component 99.15 g, 0.344 mol), cesium fluoride (15.78 g, 0.104 mol) and diethylene glycol dimethyl ether (66.94 g, 0.499 mol) were added to a 1L SUS316 autoclave equipped with a stirrer and with a pressure resistance of 8 MPa, and the mixture was cooled to 0° C. on an ice bath. Hexafluoropropylene oxide (114.22 g, 0.688 mol) was then added thereto over 2 hours, and the mixture was heated to 120° C. and reacted for 24 hours.

[0200] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain crude perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) (yellow liquid, 168.46 g). 19 In the quantitative analysis of F-NMR, 145.22 g (0.468 mol) of the target perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) was generated (yield 68% / trifluoropyruvic acid dimer basis). The target was obtained as a mixture of two diastereomers at a molar ratio of 6 / 4.

[0201] 19 F-NMR (neat, 376 MHz) (Isomer 1) δ 23.63, -77.76 (d, J = 131.6 Hz), -80.13, -81.57, -83.56 (d, J = 135.4 Hz), -124.91. (Isomer 2) δ 23.16, -78.45 (d, J = 131.6 Hz), -80.37, -81.56, -84.05 (d, J = 139.1 Hz), -123.72.

[0202] [Comparative Example 1]

[0203] Preparation of trifluoroacetone acyl fluoride dimer

[0204] Benzophenone (3.19 kg, 17.51 ​​mol) was placed in a 10 L SUS316 autoclave equipped with a stirrer and having a pressure resistance of 8 MPa, and after cooling to 0°C on an ice bath, hexafluoropropylene oxide (3.15 kg, 18.97 mol) was added thereto.

[0205] Next, the autoclave was sealed and heated to 185° C. with stirring to carry out a reaction for 4 hours. At this time, the maximum pressure reached 4.7 MPa, and then dropped to 3.5 MPa after 4 hours. However, the reaction was at a higher pressure than that in the above-mentioned Examples.

[0206] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain a crude trifluoropyruvic acid dimer (light yellow transparent liquid, 2.06 kg). 19 In the quantitative analysis of F-NMR, 1.82 kg (6.32 mol) of the target trifluoropyruvic acid dimer was generated (yield 72% / benzophenone basis).

[0207] [Example 19]

[0208] <Confirmation of products in the dimer synthesis step>

[0209] 4-Methoxybenzaldehyde (91.6 g, 0.673 mol) was added to a 500 mL SUS316 autoclave equipped with a stirrer and having a pressure resistance of 8 MPa, and after cooling to 0°C on an ice bath, hexafluoropropylene oxide (115.1 g, 0.693 mol) was added thereto.

[0210] Next, the autoclave was sealed and heated at 55° C. for 3 hours with stirring, and then heated to 150° C. to carry out a reaction for 8 hours. The maximum pressure during this period was 0.9 MPa.

[0211] After the reaction was completed, the mixture was cooled to 0°C, and the upper layer (brown, 114.3 g) and the lower layer (light yellow, 88.1 g) after separation were subjected to HPLC using trifluorotoluene as an internal standard. 19 The quantitative analysis of F-NMR confirmed that the target trifluoroacetone fluoride dimer contained 8.0 g (0.0278 mol, yield 8%, based on 4-methoxybenzaldehyde) in the upper layer and 81.5 g (0.283 mol, yield 84%, based on 4-methoxybenzaldehyde) in the lower layer. It should be noted that the main component in the upper layer was the following fluoride of 4-methoxybenzaldehyde.

[0212] [Compound 12]

[0213]

[0214] <Dimer synthesis step, dimer reaction step, isomerization step>

[0215] 4-Methoxybenzaldehyde (91.6 g, 0.673 mol) was added to a 500 mL SUS316 autoclave equipped with a stirrer and having a pressure resistance of 8 MPa, and after cooling to 0°C on an ice bath, hexafluoropropylene oxide (115.1 g, 0.693 mol) was added thereto.

[0216] Next, the autoclave was sealed and heated at 55° C. for 3 hours with stirring, and then heated to 150° C. to carry out a reaction for 8 hours. The maximum pressure during this period was 0.9 MPa.

[0217] After the reaction is completed, the reaction liquid is cooled to 0°C and separated into two layers, the upper layer and the lower layer. Cesium fluoride (14.2g, 0.0935mol) and diethylene glycol dimethyl ether (141.5g, 1.05mol) are added to the obtained reaction liquid (liquid volume 202.4g (trifluoropyruvic acid dimer 89.5g, 0.311mol)) in the autoclave, and cooled to 0°C on an ice bath. Hexafluoropropylene oxide (108.3g, 0.652mol) is added thereto over 6 hours. The temperature during this period is maintained at 0-10°C. In addition, after aging for 4 hours in the same temperature range, the autoclave is heated to 130°C again and an isomerization reaction is carried out for 24 hours.

[0218] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain crude perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) (light yellow liquid, 157.8 g). 19 In the quantitative analysis of F-NMR, 130.6 g (0.421 mol) of the target product perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) was generated (yield 63%, based on 4-methoxybenzaldehyde). The target product was a mixture of two diastereomers at a ratio of 6 / 4 (molar ratio).

[0219] 19 F-NMR (neat, 376 MHz) (Isomer 1) δ 23.63, -77.76 (d, J = 131.6 Hz), -80.13, -81.57, -83.56 (d, J = 135.4 Hz), -124.91. (Isomer 2) δ 23.16, -78.45 (d, J = 131.6 Hz), -80.37, -81.56, -84.05 (d, J = 139.1 Hz), -123.72.

[0220] [Example 20]

[0221] The same apparatus as in Example 19 was used to perform the same operations as in Example 19, and the dimer synthesis step, dimer reaction step, and isomerization step were performed. However, after the dimer synthesis reaction, a layer separation operation was performed to remove the upper layer of the reaction solution, and only the lower layer was used to perform the dimer reaction step and isomerization step. After the isomerization step, the reaction mixture was cooled to room temperature and separated to obtain crude perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) (light yellow liquid, 136.3 g). Using trifluorotoluene as the internal standard substance 19 In the quantitative analysis of F-NMR, 109.3 g (0.353 mol) of perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) as the target product was generated (yield 52%, based on 4-methoxybenzaldehyde).

[0222] Based on the above results, it can be confirmed that in Example 19, in which the dimer reaction step was performed on both the upper and lower layers of the reaction solution after the dimer synthesis step without performing a layer separation operation, the yield of perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) was improved compared to Example 20.

[0223] [Example 21]

[0224] <Confirmation of products in the dimer synthesis step>

[0225] 4-Methoxybenzaldehyde (91.6 g, 0.673 mol) and toluene (45.8 g, 0.497 mol) were added to a 500 mL SUS316 autoclave equipped with a stirrer and cooled to 0°C on an ice bath. Hexafluoropropylene oxide (115.1 g, 0.693 mol) was then added.

[0226] Next, the autoclave was sealed and heated at 55° C. for 3 hours with stirring, and then heated to 150° C. to carry out a reaction for 8 hours. The maximum pressure during this period was 0.9 MPa.

[0227] After the reaction was completed, the mixture was cooled to 0°C, and the upper layer (brown, 159.8 g) and the lower layer (light yellow, 83.4 g) after separation were subjected to HPLC using trifluorotoluene as an internal standard. 19 The quantitative analysis of F-NMR confirmed that the target trifluoroacetone fluoride dimer contained 14.6 g (0.0507 mol, yield 15%, based on 4-methoxybenzaldehyde) in the upper layer and 72.6 g (0.252 mol, yield 75%, based on 4-methoxybenzaldehyde) in the lower layer. It should be noted that the main components in the upper layer are toluene and fluoride of 4-methoxybenzaldehyde.

[0228] <Dimer synthesis step, dimer reaction step, isomerization step>

[0229] 4-Methoxybenzaldehyde (91.6 g, 0.673 mol) and toluene (45.8 g, 0.497 mol) were added to a 500 mL SUS316 autoclave equipped with a stirrer and cooled to 0°C on an ice bath. Hexafluoropropylene oxide (115.1 g, 0.693 mol) was then added.

[0230] Next, the autoclave was sealed and heated at 55° C. for 3 hours with stirring, and then heated to 150° C. to carry out a reaction for 8 hours. The maximum pressure during this period was 0.9 MPa.

[0231] After the reaction is completed, the reaction liquid is cooled to 0°C and separated into two layers, the upper layer and the lower layer. Continuously in the autoclave, cesium fluoride (11.5g, 0.0757mol) and diethylene glycol dimethyl ether (115.0g, 0.857mol) are added to the obtained reaction liquid (liquid volume 243.2g (trifluoropyruvic acid dimer 87.2g, 0.303mol)), and cooled to 0°C on an ice bath. Hexafluoropropylene oxide (105.6g, 0.636mol) is added thereto over 6 hours. The temperature during this period is maintained at 0-10°C. After further aging for 4 hours in the same temperature range, the autoclave is heated again to 130°C and an isomerization reaction is carried out for 24 hours.

[0232] After the reaction was completed, the mixture was cooled to room temperature and separated to obtain crude perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) (light yellow liquid, 155.7 g). 19 In the quantitative analysis of F-NMR, 129.0 g (0.416 mol) of the target perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) was generated (yield 62%, based on 4-methoxybenzaldehyde).

[0233] [Example 22]

[0234] The same apparatus as in Example 21 was used to perform the same operations as in Example 21, and the dimer synthesis step, dimer reaction step, and isomerization step were performed. However, after the dimer synthesis reaction, a layer separation operation was performed to remove the upper layer of the reaction solution, and only the lower layer was used to perform the dimer reaction step and isomerization step. After the isomerization step, the reaction mixture was cooled to room temperature and separated to obtain crude perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) (light yellow liquid, 122.2 g). Using trifluorotoluene as the internal standard substance 19In the quantitative analysis of F-NMR, 98.7 g (0.318 mol) of perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) as the target product was generated (yield 47%, based on 4-methoxybenzaldehyde).

[0235] Based on the above results, it can be confirmed that in Example 21, in which the dimer reaction step was performed on the upper and lower layers of the reaction solution after the dimer synthesis step without performing a layer separation operation, the yield of perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) was improved compared to Example 22.

[0236] According to one embodiment of the present invention, trifluoroacetoneyl fluoride dimer can be produced on an industrial scale. The trifluoroacetoneyl fluoride dimer obtained by the above production method can be derived into perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane), which can be used as a synthetic raw material for poly[perfluoro(2-methylene-4-methyl-1,3-dioxolane)] which is expected to be used as a resin for gas separation membranes, a transparent resin for optical fibers, and the like.

Claims

1. A method for producing a trifluoroacetone acyl fluoride dimer, the method comprising: The invention relates to a process for reacting hexafluoropropylene oxide with an aromatic aldehyde at a pressure of 3.5 MPa or less and at 0°C to 99°C for 0.5 to 12 hours to generate an aldehyde adduct of hexafluoropropylene oxide, and then performing an aging process at 100°C to 150°C for 5 to 48 hours to obtain a trifluoroacetone acyl fluoride dimer.

2. The method for producing a trifluoroacetone acyl fluoride dimer according to claim 1, wherein Aldehydes are aromatic aldehydes substituted with electron donating groups.

3. The method for producing a trifluoroacetone acyl fluoride dimer according to claim 1 or 2, wherein: Aldehydes are electron-donating group-substituted benzaldehydes.

4. The method for producing a trifluoroacetone acyl fluoride dimer according to claim 1 or 2, wherein: The aldehyde is 4-methoxybenzaldehyde.

5. A method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane), the method comprising: A dimer synthesis step of synthesizing trifluoroacetone acyl fluoride dimer by the method according to any one of claims 1 to 4; and a dimer reaction step of reacting the synthesized trifluoroacetone acyl fluoride dimer, The dimer reaction step is a step of reacting the trifluoroacetoneyl fluoride dimer with hexafluoropropylene oxide in an organic solvent in the presence of a fluoride.

6. The method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) according to claim 5, wherein After the dimer reaction step, there is an isomerization step.

7. The method for producing perfluoro(2,4-dimethyl-2-fluoroformyl-1,3-dioxolane) according to claim 5, comprising: The dimer reaction step is performed on two layers of the reaction solution separated into two layers by the method according to any one of claims 1 to 4.

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