Method for producing fluorine-containing carboxylic acid esters

Abstract

To provide a method for producing fluorine-containing carboxylic acid esters from raw materials containing fluorine-containing ketones and fluorine-containing carboxylic acid derivatives without separating and removing fluorine-containing ketones. [Solution] A method for producing a fluorine-containing carboxylic acid ester represented by the following general formula (4), comprising reacting a raw material containing a fluorine-containing isopropyl ketone represented by the following general formula (1) and a fluorine-containing carboxylic acid derivative represented by the following general formula (2) with an alcohol represented by the following general formula (3) in the presence of a basic substance having a pKa value of 2.0 or higher as the acid dissociation constant of the conjugate acid in water. TIFF2026100331000057.tif28156 (In the above general formulas (1) to (4), n is an integer from 0 to 5, m is 0 or 1, l is an integer from 0 to 50, X is a halogen atom, OR 2 , OCOR 2 and OSO2R 2 Represents either of the following, R 1 R represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents. 2 (This represents an alkyl group or haloalkyl group with 1 to 10 carbon atoms.)

Description

Technical Field

[0001] The present invention relates to a method for producing a fluorinated carboxylic acid ester.

Background Art

[0002] Fluorinated compounds having a fluorine atom in the molecule have high thermal stability and chemical stability, and thus are used in various fields as high-functional compounds. Among them, fluorinated carboxylic acid esters, which are compounds having an ester group at the terminal, are widely used as intermediates from solvents and additives to various functional materials.

[0003] For example, in Patent Document 1, it is disclosed that a methyl ester of a fluorinated carboxylic acid is useful as a non-aqueous solvent for a battery. In Patent Document 2, it is disclosed that a polyalkylene glycol ester of a fluorinated carboxylic acid is useful as a surface modifier. In Patent Document 3, it is disclosed that a methyl ester of a fluorinated carboxylic acid is useful as an intermediate in the production of a fluorinated surfactant. In Patent Document 4, it is disclosed that a methyl ester of a fluorinated carboxylic acid is useful as an intermediate in the production of a curable composition. In Patent Document 5, it is disclosed that a methyl ester of a fluorinated carboxylic acid is useful as an intermediate in the production of a surface treatment agent.

[0004] Raw materials of fluorinated carboxylic acid esters such as esters of pentafluoropropionic acid and esters of perfluoropolyether carboxylic acid include fluorinated carboxylic acid derivatives such as acyl halides and alkyl esters of the corresponding fluorinated carboxylic acids, and may further contain impurities that are difficult to separate and remove from the fluorinated carboxylic acid derivatives. Specifically, it may contain a fluorinated ketone in which a perfluoroisopropyl group is substituted on the carbonyl group of the corresponding fluorinated carboxylic acid derivative.

[0005] Here, when producing a fluorinated carboxylic acid ester using an impure fluorinated carboxylic acid acyl halide containing the above fluorinated ketone as a raw material, an impure fluorinated carboxylic acid ester containing the fluorinated ketone is obtained. However, in Non-Patent Document 1, it has been reported that a compound having a carbonyl group bonded to a perfluoroisopropyl group forms a hydrate. Therefore, due to the fluorinated ketone, there is concern that it may cause a decrease in battery performance in the use of Patent Document 1 and a decrease in mold release properties in the use of Patent Document 2.

[0006] Further, although Patent Document 4 discloses a step of reducing a methyl ester of a fluorinated carboxylic acid to a fluorinated primary alcohol, when the methyl ester of the fluorinated carboxylic acid contains a fluorinated ketone, the fluorinated ketone not only consumes the reducing agent but may also generate a fluorinated secondary alcohol as a new impurity. Furthermore, although Patent Document 5 discloses a step of converting a methyl ester of a fluorinated carboxylic acid into a fluorinated secondary alcohol using an organometallic reagent, when the methyl ester of the fluorinated carboxylic acid contains a fluorinated ketone, the fluorinated ketone not only consumes the organometallic reagent but may also generate a fluorinated tertiary alcohol as a new impurity. Against this background, removal of the fluorinated ketone in the fluorinated carboxylic acid acyl halide or fluorinated carboxylic acid ester has been studied, but an efficient removal method has not been established.

[0007] On the other hand, although a method of once converting an acyl halide or ester of a fluorinated carboxylic acid into a fluorinated carboxylic acid or the like and then separating and removing the corresponding fluorinated ketone has been studied, there is concern that the production process will increase and the operation will become complicated. Furthermore, since the fluorinated ketone is considered to occur when hexafluoropropylene is contained in the hexafluoropropylene oxide raw material used in the production of the corresponding fluorinated carboxylic acid derivative, although purification of the hexafluoropropylene oxide raw material containing hexafluoropropylene has been studied, there is concern about a decrease in productivity due to the purification process.

Prior Art Documents

[0008] [Patent Document 1] Japanese Patent Publication No. 2018-195518 [Patent Document 2] Japanese Patent Publication No. 2021-4281 [Patent Document 3] Japanese Patent Publication No. 2023-157380 [Patent Document 4] International Publication No. 2022 / 004437 [Patent Document 5] International Publication No. 2024 / 122451 [Non-patent literature]

[0009] [Non-Patent Document 1] Journal of Fluorine Chemistry, 2008, Vol. 129, pp. 178-184 [Overview of the Initiative] [Problems that the invention aims to solve]

[0010] Therefore, the present inventors diligently investigated a manufacturing method that can obtain the target product, a fluorine-containing carboxylic acid ester, even when using impure raw materials containing fluorine-containing ketones in addition to fluorine-containing carboxylic acid derivatives. As a result, they found that by reacting such low-purity raw materials with a predetermined alcohol in the presence of a basic substance, the impurity fluorine-containing ketones can be converted into fluorine-containing carboxylic acid esters, and as a result, a raw material can be provided that can suppress undesirable side reactions caused by fluorine-containing ketones.

[0011] The present invention provides a method for producing fluorine-containing carboxylic acid esters from raw materials containing fluorine-containing ketones and fluorine-containing carboxylic acid derivatives without separating and removing the fluorine-containing ketones. [Means for solving the problem]

[0012] In the method for producing a fluorinated carboxylic acid ester according to the present invention, a raw material containing a fluorinated isopropyl ketone represented by the following general formula (1) and a fluorinated carboxylic acid derivative represented by the following general formula (2) is reacted with an alcohol represented by the following general formula (3) in the presence of a basic substance having a pKa value of 2.0 or higher as the acid dissociation constant of the conjugate acid in water. [ka] (In the above general formulas (1) to (4), n is an integer from 0 to 5, and m is either 0 or 1. l is an integer between 0 and 50. X is a halogen atom, OR 2 , OCOR 2 and OSO2R 2 It represents one of the following: R 1 This represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents. R 2 (This represents an alkyl group or haloalkyl group with 1 to 10 carbon atoms.) [Effects of the Invention]

[0013] According to the present invention, a method is provided for producing fluorine-containing carboxylic acid esters with high purity without separating and removing fluorine-containing ketones from raw materials containing fluorine-containing ketones and fluorine-containing carboxylic acid derivatives. [Modes for carrying out the invention]

[0014] <Method for producing fluorinated carboxylic acid esters> In the method for producing a fluorine-containing carboxylic acid ester according to this embodiment, a raw material containing a fluorine-containing isopropyl ketone represented by the general formula (1) and a fluorine-containing carboxylic acid derivative represented by the general formula (2) is reacted with an alcohol represented by the following general formula (3) in the presence of a basic substance having a pKa value of 2.0 or more as the conjugate acid in water, whereby a fluorine-containing carboxylic acid ester represented by the general formula (4) is obtained. Thereby, even if a fluorine-containing ketone corresponding to an acyl halide or a lower alkyl ester of a fluorine-containing carboxylic acid is contained, the corresponding fluorine-containing carboxylic acid ester can be obtained without separating and removing the fluorine-containing ketone.

[0015]

Chemical formula

[0016] (Compounds represented by general formulas (1) to (4)) In general formulas (1), (2) and (4), n is 0, 1, 2, 3, 4 or 5, and is preferably an integer of 0 to 3. Also, m is 0 or 1, and when m is 1, n is preferably 1, 2, 3, 4 or 5.

[0017] In general formulas (1), (2) and (4), l is an integer of 0 to 50. The lower limit of l may be 1, 2 or 6, and the upper limit of l may be 40, 30, 20 or 15. Also, each compound represented by general formulas (1), (2) and (4) may contain a plurality of compounds showing different values of l.

[0018] In general formula (2), X is a halogen atom, OR 2 , OCOR 2 and OSO2R 2 (OS(=O)2R 2 ) and represents any one of them, and is preferably a halogen atom or OR 2 . The halogen atom is F, Cl, Br or I, and is preferably F.

[0019] In general formulas (3) to (4), R 1 represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents. The number of carbon atoms in the hydrocarbon group is preferably 1 to 9, more preferably 1 to 8, even more preferably 1 to 6, and particularly preferably 1 to 4.

[0020] The hydrocarbon group having 1 to 10 carbon atoms is not particularly limited as long as it is a hydrocarbon group consisting of carbon atoms and hydrogen atoms having 1 to 10 carbon atoms, and can include linear hydrocarbon groups, aromatic hydrocarbon groups, alicyclic hydrocarbon groups, etc. The linear hydrocarbon group is not particularly limited as long as the total number of carbon atoms is 1 to 10, and may be a straight-chain hydrocarbon group or a branched linear hydrocarbon group. The linear hydrocarbon group may also have substituents. If the hydrocarbon group having 1 to 10 carbon atoms is an aromatic hydrocarbon group, the aromatic hydrocarbon group is not particularly limited as long as the total number of carbon atoms is 6 to 10, and may be an aromatic hydrocarbon group with substituents or an aromatic hydrocarbon group without substituents. The aromatic hydrocarbon group may also have a condensed polycyclic structure. If the hydrocarbon group having 1 to 10 carbon atoms is an alicyclic hydrocarbon group, the alicyclic hydrocarbon group is not particularly limited as long as the total number of carbon atoms is 3 to 10, and may be an alicyclic hydrocarbon group with substituents or an alicyclic hydrocarbon group without substituents. The alicyclic hydrocarbon group may also have a cross-linked ring structure.

[0021] Examples of linear hydrocarbon groups include alkyl groups such as methyl, ethyl, n-propyl, i-propyl, n-butyl, iso-butyl, sec-butyl, tert-butyl, pentyl, hexyl, heptyl, octyl, nonyl, and decyl groups; Alkenyl groups such as ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, and decenyl groups; Examples include ethylyl groups, propynyl groups, butynyl groups, pentynyl groups, hexynyl groups, heptynyl groups, octinyl groups, noninyl groups, desynyl groups, and other alkynyl groups.

[0022] Examples of aromatic hydrocarbon groups include phenyl groups, benzyl groups, tolyl groups, isopropylphenyl groups, and naphthyl groups. The substituents on the phenyl groups contained in tolyl groups and isopropylphenyl groups may be located at the ortho, meta, or para positions, but the substituents are preferably located at the para position.

[0023] Examples of alicyclic hydrocarbon groups include cyclopropyl group, cyclobutyl group, cyclohexyl group, cyclopentyl group, adamantyl group, and norbornyl group.

[0024] If the linear hydrocarbon group has substituents, one of the hydrogen atoms in the linear hydrocarbon group may be substituted with an alkoxyl group or an aralkyl group. The alkoxyl group is preferably a C1-C6 alkoxyl group, such as methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy, or n-hexyloxy. The aralkyl group is preferably a C1-C6 alkyl group substituted with an aryl group, such as benzyl, phenylethyl, phenylpropyl, or naphthylmethyl.

[0025] When aromatic hydrocarbon groups and alicyclic hydrocarbon groups have substituents, examples of substituents include the C1-C6 alkyl groups and alkoxyl groups mentioned above.

[0026] R 2 R represents an alkyl group or haloalkyl group having 1 to 10 carbon atoms. The upper limit of the carbon number may be 4, 6, or 8. An alkyl group means a saturated linear hydrocarbon group or an alicyclic hydrocarbon group. As an example of a saturated linear hydrocarbon group, the above R 1 Examples include alkyl groups having 1 to 10 carbon atoms as defined above, and as saturated alicyclic hydrocarbon groups, for example, the above-mentioned R 1Examples include alicyclic hydrocarbon groups having 1 to 10 carbon atoms as defined above. Furthermore, a haloalkyl group means an alkyl group in which at least one hydrogen atom is substituted with a halogen atom, and all hydrogen atoms of the alkyl group may be substituted with halogen atoms. The number of halogen atoms in a haloalkyl group may be 1 to 3. A haloalkyl group may be a perfluoroalkyl group or a trifluoromethyl group.

[0027] In the method for producing fluorinated carboxylic acid esters according to this embodiment, the reaction between the above-mentioned raw materials and the alcohol represented by general formula (3) is carried out in the presence of a basic substance having a pKa value of 2.0 or higher as the acid dissociation constant of the conjugate acid in water, preferably a basic substance having a pKa value of 3.0 or higher as the acid dissociation constant of the conjugate acid in water, more preferably a basic substance having a pKa value of 7.0 or higher. In the present invention, by using such a basic substance, the fluorinated isopropyl group is removed from the fluorinated isopropyl ketone represented by general formula (1), and as a result, a fluorinated carboxylic acid ester represented by general formula (4) can be obtained by the reaction between the above-mentioned raw materials and the alcohol represented by general formula (3).

[0028] Examples of such basic substances include aliphatic amines, aromatic amines, heterocyclic amines, amidines, guanidines, phosphazenes, carbenes, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, and metal salts. Examples of aliphatic amines include triethylamine and diisopropylethylamine. Examples of aromatic amines include 1,8-bis(dimethylamino)naphthalene and N,N-dibutylaniline. Examples of heterocyclic amines include diazabicyclo compounds such as 1,8-diazabicyclo[5.4.0]-7-undecene, imidazole compounds such as 1-methylimidazole and 1,2-dimethylimidazole, pyridine compounds such as pyridine, 4-dimethylaminopyridine and 2,6-dimethoxypyridine, quinuclidine compounds such as quinuclidine, morpholine compounds such as N-ethylmorpholine, and triazabicyclo derivatives such as 7-methyl-1,5,7-triazabicyclo[4.4.0]deca-5-ene. Examples of quaternary phosphonium salts include tetrabutylphosphonium benzotriazolate and tetraphenylphosphonium phenoxide. Examples of amidines include N,N,N'-trimethylbenzenecarboximidoamide. Examples of guanidines include 2-tert-butyl-1,1,3,3-tetramethylguanidine. Examples of phosphazenes include tert-butylimino-tris(dimethylamino)phosphoran, 2-tert-butylimino-2-diethylamino-1,3-dimethylperhydro-1,3,2-diazaphosphorine, etc. Examples of carbenes include 1,3-di-tert-butylimidazole-2-ylidene, 1,3-bis(2,6-diisopropylphenyl)imidazolidine-2-ylidene, 1,3,4-triphenyl-4,5-dihydro-1H-1,2,4-triazole-5-ylidene, 2(3H)-thiazolylidene,3-methyl-, etc. Examples of quaternary ammonium salts include tetrabutylammonium difluorotriphenyl silicate, tetrabutylammonium succinimidate, tetrabutylammonium fluoride, tetrabutylammonium benzoate, 1-butyl-1-methylpyrrolidinium methyl carbonate, etc.Examples of tertiary sulfonium salts include tris(dimethylamino)sulfonium difluorotrimethylsilicate and dimethyl sulfoniopropionate. Examples of metal salts include metal alkoxides such as sodium methoxide and potassium nonafluoro-t-butoxide; alkali metal salts such as potassium carbonate; and cesium fluoride.

[0029] (Amount of basic substances used) In the method for producing fluorinated carboxylic acid esters according to this embodiment, the amount of basic substance used is preferably 1 mole to 110 moles, and more preferably 2 moles to 100 moles, relative to the sum of the amounts used of the fluorinated isopropyl ketone represented by general formula (1) and the fluorinated carboxylic acid derivative represented by general formula (2).

[0030] (Amount of alcohol used) In the method for producing fluorinated carboxylic acid esters according to this embodiment, the amount of alcohol represented by general formula (3) used is preferably 5 to 200 times, more preferably 40 to 150 times, and even more preferably 70 to 100 times, the sum of the amounts of fluorinated isopropyl ketone represented by general formula (1) and fluorinated carboxylic acid derivative represented by general formula (2), on a molar basis.

[0031] (Other ingredients) In the method for producing fluorinated carboxylic acid esters according to this embodiment, other components (solvents, additives, etc.) may be used in addition to the compounds represented by general formulas (1) to (3). When other components such as solvents and additives are used, their types and amounts are not particularly limited as long as they do not hinder the purpose or effects of the present invention, and the types and amounts can be appropriately selected according to the purpose.

[0032] The molar ratio of fluorinated isopropyl ketone to fluorinated carboxylic acid derivative used in the above reaction is preferably 1:1 to 1:15, and more preferably 1:7 to 1:13. If necessary, operations to increase the molar ratio of fluorinated isopropyl ketone to fluorinated carboxylic acid derivative, such as distillation or recrystallization, may be performed before the reaction.

[0033] In a method for producing a fluorinated carboxylic acid ester according to one embodiment of the present invention, a raw material containing a fluorinated isopropyl ketone represented by general formula (1) and a fluorinated carboxylic acid derivative represented by general formula (2) may be added dropwise or in multiple portions to a mixture of an alcohol represented by general formula (3) and the basic substance described above.

[0034] The reaction temperature and reaction time are not particularly limited as long as the reaction proceeds at a temperature and time that allows the fluorine-containing carboxylic acid ester to be obtained. The reaction temperature is preferably, for example, 0 to 100°C, more preferably 5 to 90°C, even more preferably 10 to 70°C, and particularly preferably 15 to 50°C. The reaction time is preferably, for example, 0.5 to 100 hours, more preferably 1 to 90 hours, even more preferably 5 to 75 hours, even more preferably 10 to 50 hours, and particularly preferably 12 to 24 hours.

[0035] After the reaction, the fluorinated carboxylic acid ester may be obtained without distillation to remove alcohols or basic substances, or it may be isolated by distillation. Alternatively, the fluorinated carboxylic acid ester may be isolated after the reaction without chromatography (e.g., silica gel column chromatography or ion exchange chromatography).

[0036] In the method for producing fluorinated carboxylic acid esters according to this embodiment, the yield when the target product, a fluorinated carboxylic acid ester represented by general formula (4), is isolated is preferably 90% or more of the total number of moles of fluorinated isopropyl ketone and fluorinated carboxylic acid derivative. Furthermore, the obtained fluorinated carboxylic acid ester is useful for various applications such as lubricants, coatings, surfactants, and antibacterial agents.

[0037] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and includes all aspects included in the concept and claims of the present invention, and can be modified in various ways within the scope of the present invention.

[0038] Based on the embodiments described above, the present invention relates to the following [1] to [6]. [1] A method for producing a fluorine-containing carboxylic acid ester represented by the following general formula (4), characterized by reacting a raw material containing a fluorine-containing isopropyl ketone represented by the following general formula (1) and a fluorine-containing carboxylic acid derivative represented by the following general formula (2) with an alcohol represented by the following general formula (3) in the presence of a basic substance having a pKa value of 2.0 or higher as the acid dissociation constant of the conjugate acid in water. [ka] (In the above general formulas (1) to (4), n is an integer from 0 to 5, and m is either 0 or 1. l is an integer between 0 and 50. X is a halogen atom, OR 2 , OCOR 2 and OSO2R 2 It represents one of the following: R 1 This represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents. R 2 (This represents an alkyl group or haloalkyl group with 1 to 10 carbon atoms.) [2] The method for producing a fluorine-containing carboxylic acid ester according to [1] above, wherein the basic substance has a pKa value of 3.0 or higher as the acid dissociation constant of the conjugate acid in water. [3] A method for producing a fluorine-containing carboxylic acid ester according to [1] or [2] above, wherein the basic substance is selected from the group consisting of aliphatic amines, aromatic amines, heterocyclic amines, amidines, guanidines, phosphazenes, carbenes, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, and metal salts. [4] A method for producing a fluorine-containing carboxylic acid ester according to any one of [1] to [3] above, wherein the molar ratio of the fluorine-containing isopropyl ketone used in the reaction to the fluorine-containing carboxylic acid derivative is 1:1 to 1:15. [5] A method for producing a fluorine-containing carboxylic acid ester according to any one of [1] to [4] above, wherein the reaction temperature of the reaction is 0 to 100°C. [6] In the above general formula (2), X is a halogen atom or OR 2 A method for producing a fluorine-containing carboxylic acid ester according to any one of the above [1] to [5]. [7] In the above general formulas (3) and (4), R 1 A method for producing a fluorine-containing carboxylic acid ester according to any one of [1] to [6] above, wherein is a hydrocarbon group having 1 to 4 carbon atoms. [Examples]

[0039] Examples of the present invention are described below, but the present invention is not limited to these examples unless it exceeds the spirit of the invention. Unless otherwise specified, each operation is performed at room temperature, and room temperature is defined as being within the range of 20°C ± 5°C. The pKa values ​​of the basic substances shown below are literature values ​​or estimated values ​​for similar compounds.

[0040] (Example 1) A flask equipped with a stirring blade, condenser, and thermometer was mixed with 41.36 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.028 mol of methyl perfluoropolyether carboxylate and 0.002 mol of the corresponding fluorine-containing isopropyl ketone.

[0041] [ka]

[0042] Next, 83.1 g (2.59 mol) of methanol was added to the flask containing the above mixture, followed by 0.247 g (0.0016 mol) of 1,8-diazabicyclo[5.4.0]-7-undecene (pKa value: 11.3~13.5), and the mixture was stirred at room temperature for 2 hours. 19 In 1F-NMR, the signal for fluorine-containing isopropyl ketone disappeared, and the signal for perfluoropolyether carboxylate methyl ester increased. Furthermore, the reaction mixture was allowed to stand and separate into layers, and the lower layer was collected and washed three times with 3N hydrochloric acid aqueous solution and water. Finally, methanol and water were removed by simple distillation to obtain perfluoropolyether carboxylate methyl ester in 91.6% yield. The obtained perfluoropolyether carboxylate methyl ester was also analyzed by GC-FID and GC-MS, and in both cases, the content of fluorine-containing isopropyl ketone was confirmed to be below the detection limit.

[0043] [ka]

[0044] (Example 2) A flask equipped with a stirring blade, condenser, and thermometer was mixed with 110.2 g of a mixture containing the compound shown in the following structural formula. 19The composition of the mixture, calculated by 1F-NMR, was 0.0745 mol of methyl perfluoropolyether carboxylate and 0.0055 mol of the corresponding fluorine-containing isopropyl ketone.

[0045] [ka]

[0046] Next, 250.7 g (7.82 mol) of methanol was added to the flask containing the above mixture, followed by 0.21 g (0.0021 mol) of triethylamine (pKa value: 10.3-11.0), and the mixture was stirred at room temperature for 22 hours. 19 In 1F-NMR, the signal for fluorine-containing isopropyl ketone disappeared, and the signal for perfluoropolyether carboxylate methyl ester increased. Furthermore, the reaction mixture was allowed to stand and separate into layers, and the lower layer was collected. Methanol and triethylamine were removed from the lower layer by simple distillation to obtain perfluoropolyether carboxylate methyl ester in 96.5% yield.

[0047] [ka]

[0048] (Example 3) A flask equipped with a stirring blade, condenser, and thermometer was mixed with 300.3 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.198 mol of methyl perfluoropolyether carboxylate and 0.020 mol of the corresponding fluorine-containing isopropyl ketone.

[0049] [ka]

[0050] Next, 453.2 g (14.14 mol) of methanol was added to the flask containing the above mixture, followed by 2.1 g (0.022 mol) of 1,2-dimethylimidazole (pKa value: 8.0), and the mixture was stirred at room temperature for 18 hours. 19 In 1F-NMR, the signal for fluorine-containing isopropyl ketone disappeared, and the signal for perfluoropolyether carboxylate methyl ester increased. Furthermore, the reaction mixture was allowed to stand and separate into layers, and the lower layer was collected and washed three times with methanol. Finally, methanol was removed by simple distillation to obtain perfluoropolyether carboxylate methyl ester in 94.9% yield.

[0051] [ka]

[0052] (Example 4) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0053] [ka]

[0054] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.043 g (0.00035 mol) of 4-dimethylaminopyridine (pKa value: 9.6~9.9), and the mixture was stirred at room temperature for 3 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0055] [ka]

[0056] (Example 5) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0057] [ka]

[0058] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.033 g (0.00030 mol) of quinuclidine (pKa value: 11.0), and the mixture was stirred at room temperature for 2 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0059] [ka]

[0060] (Example 6) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0061] [ka]

[0062] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.128 g (0.00060 mol) of 1,8-bis(dimethylamino)naphthalene (pKa value: 12.0), and the mixture was stirred at room temperature for 24 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0063] [ka]

[0064] (Example 7) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0065] [ka]

[0066] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.124 g (0.00033 mol) of tetrabutylphosphonium benzotriazolate (pKa value: 8.4-8.7), and the mixture was stirred at room temperature for 21 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0067] [ka]

[0068] (Example 8) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0069] [ka]

[0070] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.073 g (0.00063 mol) of N-ethylmorpholine (pKa value: 8.0), and the mixture was stirred at room temperature for 31 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0071] [ka]

[0072] (Example 9) A sample vial containing a stirring bar was mixed with 9.9 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, as calculated by 1F-NMR, was 0.02 mol of methyl pentafluoropropanoate and 0.02 mol of the corresponding fluorine-containing isopropyl ketone.

[0073] [ka]

[0074] Next, 9.9 g (0.31 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.30 g (0.002 mol) of 1,8-diazabicyclo[5.4.0]-7-undecene, and the mixture was stirred at room temperature for 1 hour.19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for methyl pentafluoropropanoate increased.

[0075] [ka]

[0076] (Example 10) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0077] [ka]

[0078] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.0725 g (0.0003 mol) of cesium fluoride (pKa value: 3.2-4.0), and the mixture was stirred at room temperature for 41 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0079] [ka]

[0080] (Example 11) A flask equipped with a stirring blade, condenser, and thermometer was mixed with 603.5 g (18.836 mol) of methanol and 38.7 g (0.382 mol) of triethylamine and stirred. Next, 500.0 g of a mixture containing the compound shown in the following structural formula was added to a dropping funnel. 19The composition of the mixture, as calculated by 1F-NMR, was 0.352 mol of perfluoropolyether acid fluoride and 0.032 mol of the corresponding fluorine-containing isopropyl ketone.

[0081] [ka]

[0082] The above mixture was introduced into a dropping funnel and slowly added dropwise. After the addition was complete, the mixture was stirred at room temperature for 2 hours. 19 In 1F-NMR, the signal for fluorine-containing isopropyl ketone disappeared, and the signal for perfluoropolyether carboxylate methyl ester increased. Furthermore, the reaction mixture was allowed to stand and separate into layers, and the lower layer was collected and washed three times with methanol. Finally, methanol was removed by simple distillation to obtain perfluoropolyether carboxylate methyl ester in 90.8% yield. The obtained perfluoropolyether carboxylate methyl ester was also analyzed by GC-FID and confirmed that the content of fluorine-containing isopropyl ketone was below the detection limit.

[0083] [ka]

[0084] (Example 12) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0085] [ka]

[0086] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.163 g (0.0003 mol) of tetrabutylammonium difluorotriphenyl silicate (pKa value: 3.2~4.0), and the mixture was stirred at room temperature for 20 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0087] [ka]

[0088] (Example 13) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0089] [ka]

[0090] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.084 g (0.0003 mol) of tris(dimethylamino)sulfonium difluorotrimethylsilicate (pKa value: 3.2~4.0), and the mixture was stirred at room temperature for 20 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased. [ka]

[0091] (Example 14) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0092] [ka]

[0093] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.103 g (0.0003 mol) of tetrabutylammonium succinimidate (pKa value: 10.0), and the mixture was stirred at room temperature for 20 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0094] [ka]

[0095] (Example 15) A 100 mL three-necked flask equipped with a stirring bar, a Liebig bottle cap, and a thermocouple was used to introduce 5.00 g of a mixture containing the compound shown in the following structural formula, and the mixture was stirred. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0033 mol of methyl perfluoropolyether carboxylate and 0.0003 mol of the corresponding fluorine-containing isopropyl ketone.

[0096] [ka]

[0097] Next, 12.0 g (0.37 mol) of methanol was added to the flask containing the above mixture, followed by 0.029 g (0.0004 mol) of pyridine (pKa value: 5.1~6.8), and the mixture was heated under reflux at an oil bath setting of 90°C for 14 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone decreased, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0098] [ka]

[0099] (Example 16) A sample vial containing a stirring bar was mixed with 4.1 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0028 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0100] [ka]

[0101] Next, 9.0 g (0.28 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.0331 g (0.0004 mol) of 1-methylimidazole (pKa value: 7.0), and the mixture was stirred at room temperature for 21 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone decreased, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0102] [ka]

[0103] (Example 17) A sample vial containing a stirring bar was mixed with 4.8 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0043 mol of methyl perfluoropolyether carboxylate and 0.0006 mol of the corresponding fluorine-containing isopropyl ketone.

[0104] [ka]

[0105] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.103 g (0.0005 mol) of N,N-dibutylaniline (pKa value: 5.2~6.6), and the mixture was stirred at room temperature for 20 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0106] [ka]

[0107] (Example 18) A sample vial containing a stirring bar was mixed with 4.8 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0043 mol of methyl perfluoropolyether carboxylate and 0.0006 mol of the corresponding fluorine-containing isopropyl ketone.

[0108] [ka]

[0109] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.90 g (0.0005 mol) of 1,3-di-tert-butylimidazole-2-ylidene (pKa value: 28.0), and the mixture was stirred at room temperature for 2 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0110] [ka]

[0111] (Example 19) A sample vial containing a stirring bar was mixed with 7.0 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, as calculated by 1F-NMR, was 0.0045 mol of methyl perfluoropolyether carboxylate and 0.0002 mol of the corresponding fluorine-containing isopropyl ketone.

[0112] [ka]

[0113] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.090 g (0.0005 mol) of 5 mol / L sodium methoxide / MeOH (pKa value: 16.0) solution, and the mixture was stirred at room temperature for 2 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0114] [ka]

[0115] (Example 20) A sample vial containing a stirring bar was mixed with 4.8 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0043 mol of methyl perfluoropolyether carboxylate and 0.0006 mol of the corresponding fluorine-containing isopropyl ketone.

[0116] [ka]

[0117] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.18 g (0.0005 mol) of tetrabutylammonium benzoate (pKa value: 4.0), and the mixture was stirred at room temperature for 16 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0118] [ka]

[0119] (Example 21) A sample vial containing a stirring bar was mixed with 4.8 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0043 mol of methyl perfluoropolyether carboxylate and 0.0006 mol of the corresponding fluorine-containing isopropyl ketone.

[0120] [ka]

[0121] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.14 g (0.0005 mol) of potassium nonafluoro-t-butoxide (pKa value: 4.1~5.4), and the mixture was stirred at room temperature for 16 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0122] [ka]

[0123] (Example 22) A sample vial containing a stirring bar was mixed with 4.0 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0033 mol of methyl perfluoropolyether carboxylate and 0.0012 mol of the corresponding fluorine-containing isopropyl ketone.

[0124] [ka]

[0125] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.07 g (0.0005 mol) of potassium carbonate (pKa1: 6.4-3.8, pKa2: 10.0), and the mixture was stirred at room temperature for 3 hours. 19 In 1F-NMR, we confirmed that the signal for fluorine-containing isopropyl ketone disappeared, while the signal for perfluoropolyether carboxylate methyl ester increased.

[0126] [ka]

[0127] (Example 23) 10.0 g (0.135 mol) of t-butanol and 0.6 g (0.006 mol) of triethylamine were added to a sample vial containing a stirring bar and stirred. Then, 6.9 g of a mixture containing the compound shown in the following structural formula was slowly added. 19 The composition of the mixture, as calculated by F-NMR, was 0.004 mol of perfluoropolyether acid fluoride and 0.0004 mol of the corresponding fluorine-containing isopropyl ketone.

[0128] [ka]

[0129] After the introduction was complete, the mixture was stirred at room temperature for 3 hours. 19 In 1F-NMR, the signal for perfluoropolyether acid fluoride disappeared, the signal for fluorinated isopropyl ketone decreased, and the signal for perfluoropolyether carboxylate t-butyl ester was generated.

[0130] [ka]

[0131] (Example 24) In a sample vial containing a stirring bar, 10.0 g (0.083 mol) of diethylene glycol monomethyl ether and 0.6 g (0.006 mol) of triethylamine were introduced and stirred. Then, 6.9 g of a mixture containing the compound shown in the following structural formula was slowly introduced. 19 The composition of the mixture, as calculated by F-NMR, was 0.004 mol of perfluoropolyether acid fluoride and 0.0004 mol of the corresponding fluorine-containing isopropyl ketone.

[0132] [ka]

[0133] After the introduction was complete, the mixture was stirred at room temperature for 3 hours.19 In 1F-NMR, we confirmed that the signal for perfluoropolyether acid fluoride disappeared, as did the signal for fluorinated isopropyl ketone, while the signal for perfluoropolyether carboxylic acid methoxyethoxyethyl ester was generated. [ka]

[0134] (Example 25) In a sample vial containing a stirring bar, 10.0 g (0.106 mol) of phenol, 10.0 g (0.111 mol) of monoglyme, and 0.6 g (0.006 mol) of triethylamine were introduced and stirred. Then, 6.9 g of a mixture containing the compound shown in the following structural formula was slowly introduced. 19 The composition of the mixture, as calculated by F-NMR, was 0.004 mol of perfluoropolyether acid fluoride and 0.0004 mol of the corresponding fluorine-containing isopropyl ketone.

[0135] [ka]

[0136] After the introduction was complete, the mixture was stirred at room temperature for 16 hours. 19 In 1F-NMR, the signal for perfluoropolyether acid fluoride disappeared, the signal for fluorinated isopropyl ketone decreased, and the signal for perfluoropolyether carboxylic acid phenyl ester was generated.

[0137] [ka]

[0138] (Comparative Example 1) A sample vial containing a stirring bar was mixed with 4.8 g of a mixture containing the compound shown in the following structural formula. 19The composition of the mixture, calculated by 1F-NMR, was 0.0043 mol of methyl perfluoropolyether carboxylate and 0.0006 mol of the corresponding fluorine-containing isopropyl ketone.

[0139] [ka]

[0140] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.09 g (0.0005 mol) of diphenylamine (pKa value: 0.8), and the mixture was stirred at room temperature for 24 hours. 19 In 1F-NMR, there was no change in the signals for fluorine-containing isopropyl ketone or perfluoropolyether carboxylate methyl ester, confirming that the reaction had not proceeded.

[0141] (Comparative Example 2) A sample vial containing a stirring bar was mixed with 4.8 g of a mixture containing the compound shown in the following structural formula. 19 The composition of the mixture, calculated by 1F-NMR, was 0.0043 mol of methyl perfluoropolyether carboxylate and 0.0006 mol of the corresponding fluorine-containing isopropyl ketone.

[0142] [ka]

[0143] Next, 10.0 g (0.29 mol) of methanol was added to the sample bottle containing the above mixture, followed by 0.07 g (0.0005 mol) of 2,6-dimethoxypyridine (pKa value: 1.6), and the mixture was stirred at room temperature for 24 hours. 19 In 1F-NMR, there was no change in the signals for fluorine-containing isopropyl ketone or perfluoropolyether carboxylate methyl ester, confirming that the reaction had not proceeded.

Claims

1. A method for producing a fluorine-containing carboxylic acid ester represented by the following general formula (4), characterized by reacting a raw material containing a fluorine-containing isopropyl ketone represented by the following general formula (1) and a fluorine-containing carboxylic acid derivative represented by the following general formula (2) with an alcohol represented by the following general formula (3) in the presence of a basic substance having a pKa value of 2.0 or higher as the acid dissociation constant of the conjugate acid in water. 【Chemistry 1】 (In the above general formulas (1) to (4), n is an integer from 0 to 5, and m is 0 or 1. l is an integer between 0 and 50. X is a halogen atom, OR ２ ,OCOR ２ and OSO ２ R ２ It represents one of the following: R １ This represents a hydrocarbon group having 1 to 10 carbon atoms, which may have substituents. R ２ (This represents an alkyl group or haloalkyl group having 1 to 10 carbon atoms.)

2. The method for producing a fluorine-containing carboxylic acid ester according to claim 1, wherein the basic substance has a pKa value of 3.0 or higher as the acid dissociation constant of the conjugate acid in water.

3. A method for producing a fluorine-containing carboxylic acid ester according to claim 1 or 2, wherein the basic substance is selected from the group consisting of aliphatic amines, aromatic amines, heterocyclic amines, amidines, guanidines, phosphazenes, carbenes, quaternary ammonium salts, quaternary phosphonium salts, tertiary sulfonium salts, and metal salts.

4. A method for producing a fluorine-containing carboxylic acid ester according to claim 1 or 2, wherein the molar ratio of the fluorine-containing isopropyl ketone used in the reaction to the fluorine-containing carboxylic acid derivative is 1:1 to 1:

15.

5. A method for producing a fluorine-containing carboxylic acid ester according to claim 1 or 2, wherein the reaction temperature of the above reaction is 0 to 100°C.

6. In the above general formula (2), X is a halogen atom or OR ２ A method for producing a fluorine-containing carboxylic acid ester according to claim 1 or 2.

7. In the above general formulas (3) and (4), R １ A method for producing a fluorine-containing carboxylic acid ester according to claim 1 or 2, wherein represents a hydrocarbon group having 1 to 4 carbon atoms.

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