Method for producing fluorine-containing ester compound and method for producing fluorine-containing diol compound

Abstract

A method for producing a fluorine-containing ester compound comprising at least the following steps (A) and (B). The step (A) is a step for subjecting a diol compound (1) to a Michael addition reaction with an alkyl acrylate or acrylonitrile and then performing a transesterification reaction to obtain a compound (2a) terminated with ester groups at both ends. The step (B) is a step for fluorinating the compound (2a) terminated with ester groups at both ends and then reacting the same with an alkyl alcohol to obtain a fluorine-containing ester compound (3) represented by formula (3). (3): R5O-C(=O)-CF2CF2-O-(Rf1-O)x-CF2CF2-C(=O)-OR5 (Rf1 is a divalent perfluorohydrocarbon group. R5 is a C1-10 alkyl group. x is an integer of 1-20.)

Description

Method for producing fluorine-containing ester compound and method for producing fluorine-containing diol compound

[0001] The present invention relates to a method for producing a fluorine-containing ester compound, a method for producing a fluorine-containing diol compound, and a fluorine-containing diol compound. The present application claims priority based on Japanese Patent Application No. 2025-030255 filed in Japan on February 27, 2025, the content of which is incorporated herein by reference.

[0002] Conventionally, fluorine-containing diol compounds, in which terminal groups having a hydroxyl group are bonded to both ends of a skeleton composed of a perfluoropolyether chain (PFPE chain), have been widely used as raw materials for lubricants and the like. As a method for producing such a fluorine-containing diol compound, there has been proposed a production method including a step of protecting hydroxyl groups arranged at both terminals of polyalkylene glycol with a protecting group to obtain a raw material compound, and then fluorinating the raw material compound.

[0003] For example, Patent Document 1 discloses that an operation of adjusting the molecular weight distribution of a polymer compound having a structural unit is performed to obtain R ４ -O-(R １ -O) ｘ -R ５ (R １ is a divalent hydrocarbon group having 2 to 5 carbon atoms. R ４ and R ５ are each independently a protecting group for a hydroxyl group. x is an average degree of polymerization. ), which is a method for producing a fluorinated polyether, comprising a step (1) of obtaining a raw material compound represented by the formula, and a step (2) of introducing the raw material compound, an inert gas, fluorine gas, and a solvent into a reactor after the step (1) to fluorinate the raw material compound.

[0004] Further, for example, Patent Document 2 discloses R having Mw / Mn representing a molecular weight distribution of 1.30 or less ４ -O-(R １ -O) ｘ -R ５ (R １ is a divalent hydrocarbon group having 2 to 5 carbon atoms. R ４ and R ５Each of the following is an independent protecting group for a hydroxyl group. x is the average degree of polymerization. A method for producing a fluorinated polyether is described, comprising the step (1) of introducing a raw material compound represented by (a), an inert gas, a fluorine gas, and a solvent into a reactor to fluorinate the raw material compound.

[0005] International Publication No. 2023 / 058753(A) International Publication No. 2023 / 058754(A)

[0006] In recent years, there has been a growing expectation for structural diversification in fluorine-containing diol compounds, which have a perfluoropolyether chain (PFPE chain) skeleton with hydroxyl terminal groups bonded to both ends. Specifically, there is a demand for such fluorine-containing diol compounds that have a skeleton consisting of a perfluoropolyether chain derived from the structural units of the starting compound, with linking groups consisting of divalent perfluorohydrocarbon groups not derived from the structural units of the starting compound bonded to both ends.

[0007] However, when producing fluorinated diol compounds having a skeleton composed of perfluoropolyether chains using fluorinated polyethers produced by conventional manufacturing methods, it was difficult to produce fluorinated diol compounds in which structures not derived from the structural units of the raw material compound are bonded to both ends of the skeleton composed of perfluoropolyether chains derived from the structural units of the raw material compound of the fluorinated polyether, as shown below.

[0008] In other words, a fluorinated polyether is obtained by protecting the hydroxyl groups located at both ends of a polyalkylene glycol with a protecting group to form a starting compound, and then fluorinating this starting compound. The fluorinated polyether has a skeleton consisting of a perfluoropolyether chain formed by fluorinating the structure obtained by removing the structural units located at both ends of the starting compound from the structural units of the starting compound. This fluorinated polyether has linking groups, each consisting of specific divalent perfluorohydrocarbon groups derived from the structural units located at both ends of the starting compound, bonded to both ends of the skeleton.

[0009] As a result, the fluorinated diol compounds produced using the above-mentioned fluorinated polyethers have hydroxyl groups bonded to both ends of a perfluoropolyether chain skeleton via linking groups consisting of specific divalent perfluorohydrocarbon groups derived from the structural units of the raw material compound of the fluorinated polyether.

[0010] The present invention has been made in view of the above circumstances, and has a skeleton consisting of a perfluoroether chain derived from the structural unit of the raw material compound, with -CF at both ends, regardless of the structural unit of the raw material compound. ２ CF ２ The objective is to provide a method for producing fluorine-containing ester compounds that can be suitably used as a raw material for fluorine-containing diol compounds having a structure in which a hyphen is bonded.

[0011] Furthermore, the present invention provides a framework consisting of a perfluoroether chain derived from the structural unit of the raw material compound, with -CF at both ends, regardless of the structural unit of the raw material compound. ２ CF ２ The objective of this invention is to provide a method for producing a fluorine-containing diol compound having a structure in which - is bonded. Furthermore, the present invention provides a framework consisting of a perfluoroether chain derived from the structural unit of the raw material compound, with -CF not derived from the structural unit of the raw material compound at both ends. ２ CF ２ The objective is to provide a fluorine-containing diol compound having a structure in which a negative sign is bonded.

[0012] In other words, the present invention relates to the following matters.

[0013] [1] The process includes at least step (A) and step (B) below, wherein step (A) is a process including the following steps (A-1) and (A-2) below (where R in formula (2) below) ２ A method for producing a fluorine-containing ester compound, characterized in that if the group is not a cyano group, step (A-2) may be omitted.

[0014] [Step (A-1)] Step (A-1) is a step in which a diol compound (1) represented by the following formula (1) is subjected to a Michael addition reaction in the presence of a base with at least one unsaturated compound selected from alkyl acrylates, which are ester compounds of alkyl alcohols having 1 to 10 carbon atoms and acrylic acid, and acrylonitrile, to obtain a compound (2) represented by the following formula (2).

[0015] HO-(R １ -O) ｘ -H (1) (In formula (1), R １ x represents a divalent hydrocarbon group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. x is an integer from 1 to 20. (R １ R in x structural units represented by -O) １ They may all be the same, or some or all of them may be different.

[0016] R ２ -CH ２ CH ２ -O-(R １ -O) ｘ -CH ２ CH ２ -R ２ (2) (In formula (2), R １ And x are the same as in equation (1). R ２ is -C(=O)-OR ３ (R ３ represents an alkyl group with 1 to 10 carbon atoms. ) or a cyano group. Two R ２ They may be the same or they may be different.

[0017] [Step (A-2)] Step (A-2) is a step of converting compound (2) to a terminal ester compound (2a) represented by the following formula (2a). R in formula (2) ２ If it is not a cyano group and step (A-2) is not omitted, R ３ and R ４ These are different alkyl groups. ４ OC(=O)-CH ２ CH ２ -O-(R １ -O) ｘ-CH ２ CH ２ -C (=O) -OR ４ (2a) (In formula (2a), R １ And x are the same as in equation (1). R ４ The R represents an alkyl group with 1 to 10 carbon atoms. ４ They may be the same or they may be different.

[0018] [Step (B)] Step (B) involves fluorinating the two terminal ester compounds (2a) to obtain an intermediate compound (3a) represented by the following formula (3a), and then F-C(=O)-CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -C(=O)-F (3a) (In formula (3a), Rf １ R in equation (1) １ This represents a divalent perfluorohydrocarbon group in which a hydrogen atom is replaced by a fluorine atom. (x is the same as in formula (1).)

[0019] The intermediate compound (3a) is R ５ -OH(R) ５ R represents an alkyl group having 1 to 10 carbon atoms. This is a step to obtain a fluorine-containing ester compound (3) represented by the following formula (3) by reacting it with an alkyl alcohol represented by ( ). ５ OC(=O)-CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -C (=O) -OR ５ (3) (In formula (3), Rf １ R in equation (1) １ R represents a divalent perfluorocarbon group in which a hydrogen atom is replaced by a fluorine atom. ５ The R represents an alkyl group with 1 to 10 carbon atoms. ５ x may be the same or different. x is the same as in equation (1).

[0020] [2] The method for producing a fluorine-containing ester compound according to [1], wherein the unsaturated compound is the alkyl acrylate. [3] The unsaturated compound is the alkyl acrylate, and R in the compound (2) ２ is -C(=O)-OR ３ (R ３ represents an alkyl group having 1 to 10 carbon atoms.), and the step (A-2) is a transesterification step (A-2-1) of obtaining the both-terminal ester compound (2a) by transesterifying the compound (2), the method for producing a fluorine-containing ester compound according to [1] or [2].

[0021] [4] The method for producing a fluorine-containing ester compound according to [1], wherein the unsaturated compound is acrylonitrile. [5] The unsaturated compound is acrylonitrile, and R in the compound (2) ２ is -CN, and the step (A-2) is an alcoholysis step (A-2-2) of obtaining the both-terminal ester compound (2a) by subjecting the cyano group of the compound (2) to alcoholysis, the method for producing a fluorine-containing ester compound according to [1] or [4].

[0022] [6] x pieces of R in the formula (1) １ are each independently -CH ２ -, -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -, -CH ２ CH(CH ３ )-, -CH ２ CH ２ CH ２ CH ２ -, -CF ２ -, -CF ２ CF ２ -, -CF ２ CF ２ CF ２ -, -CF(CF ３ )CF ２ -, -CF ２ CF(CF３ ) -, -CF ２ CF ２ CF ２ CF ２ -, -CF ２ CH ２ -ien-CH ２ CF ２ -, -CF ２ CF ２ CH ２ -ien-CH ２ CF ２ CF ２ -, -CF ２ CF ２ CF ２ CH ２ -, and -CH ２ CF ２ CF ２ CF ２ - (The left-hand joint is (R １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (R １ A method for producing a fluorine-containing ester compound according to any one of [1] to [5], selected from the group consisting of (bonding to an oxygen atom in -O).

[0023] [7] x R in formula (1) １ All are identical, -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -ien-CH ２ CH (CH ３ ) -, -CH ２ CH ２ CH ２ CH ２ - (The left-hand joint is (R １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (R １ A method for producing a fluorine-containing ester compound according to any one of [1] to [5], wherein one is selected from the group consisting of (bonding to an oxygen atom in -O).

[0024] [8] x R in formula (1) １ Each of them independently, -CH(CH３ )CH ２ - and -CH ２ CH(CH ３ )- (the left-hand bond binds to an oxygen atom to which a structural unit represented by (R １ -O) binds, and the right-hand bond binds to an oxygen atom in (R １ -O)), the method for producing a fluorine-containing ester compound according to any one of [1] to [5].

[0025] [9] The method for producing a fluorine-containing ester compound according to any one of [1] to [8], wherein in the step (A-1), a molar ratio of the unsaturated compound to the diol compound (1) (unsaturated compound) / (diol compound) is 2.0 to 5.0.

[10] The method for producing a fluorine-containing ester compound according to any one of [1] to [9], wherein the base in the step (A-1) is at least one selected from the group consisting of potassium tert-butoxide, sodium hydride and potassium hydroxide.

[0026]

[11] A method for producing a fluorine-containing diol compound represented by the following formula (4), comprising: a step of producing the fluorine-containing ester compound (3) represented by the formula (3) by the method for producing a fluorine-containing ester compound according to any one of [1] to

[10] ; and a step (C) of reducing an ester moiety of the fluorine-containing ester compound (3), wherein: HO-CH ２ -CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -CH ２ -OH (4) (in the formula (4), Rf １ and x are the same as in the formula (3).)

[0027]

[12] A fluorine-containing diol compound represented by the following formula (4a): HO-CH ２ -CF ２ CF ２ -O-(Rf １ａ -O) ｘ -CF ２ CF ２ -CH ２-OH (4a) (in formula (4a), Rf １ａ represents a divalent perfluorohydrocarbon group having 1 to 10 carbon atoms. x is an integer of 1 to 20. Rf in x structural units represented by (Rf １ａ -O) １ａ may all be the same, or some or all may be different. However, in formula (4a), the case where all Rf １ａ are -CF ２ CF ２ CF ２ - is excluded.)

[0028]

[13] The fluorine-containing diol compound according to

[12] , wherein all Rf in formula (4a) １ａ are -CF ２ CF ２ -.

[14] The fluorine-containing diol compound according to

[12] , wherein each Rf in formula (4a) １ａ is independently selected from the group consisting of -CF(CF ３ )CF ２ - and -CF ２ CF(CF ３ )- (the bond on the left side bonds to the oxygen atom to which the structural unit represented by (Rf １ａ -O) bonds, and the bond on the right side bonds to the oxygen atom in (Rf １ａ -O)).

[15] The fluorine-containing diol compound according to

[12] , wherein all Rf in formula (4a) １ａ are -CF ２ CF ２ CF ２ CF ２ -.

[0029] According to the method for producing a fluorine-containing ester compound of the present invention, a fluorine-containing ester compound having -CF ２ CF ２ -C(=O)-O- at both ends of a skeleton composed of a perfluoroether chain derived from the structural unit of a raw material compound can be produced, regardless of the structural unit of the raw material compound.

[0030] Furthermore, according to the method for producing fluorine-containing diol compounds of the present invention, the ester portion of the fluorine-containing ester compound produced by the method of the present invention is reduced, so regardless of the structural units of the raw material compound, -CF ２ CF ２ -CH ２ Fluorine-containing diol compounds having a structure in which terminal groups consisting of -OH are bonded can be produced.

[0031] Furthermore, the fluorine-containing diol compound of the present invention has a skeleton consisting of a perfluoroether chain derived from the structural unit of the raw material compound, with -CF at both ends. ２ CF ２ -CH ２ It has a structure to which terminal groups consisting of -OH are bonded. For this reason, the fluorine-containing diol compounds of the present invention are useful as raw materials for lubricants and the like.

[0032] The following describes in detail the method for producing fluorine-containing ester compounds, fluorine-containing diol compounds, and the method for producing fluorine-containing diol compounds according to the present invention. Note that the present invention is not limited to the embodiments shown below. [Method for producing fluorine-containing ester compounds] The method for producing fluorine-containing ester compounds according to this embodiment is a method for producing a fluorine-containing ester compound represented by formula (3), which will be described later. The method for producing fluorine-containing ester compounds according to this embodiment includes at least the following steps (A) and (B).

[0033] <Process (A)> Process (A) is a process that includes the following processes (A-1) and (A-2). However, R in the following formula (2) ２ If the group is not a cyano group, step (A-2) may be omitted.

[0034] [Step (A-1)] Step (A-1) is a step in which a diol compound (1) represented by the following formula (1) and at least one unsaturated compound selected from the group consisting of alkyl acrylates (hereinafter sometimes referred to as "alkyl acrylates"), which are ester compounds of alkyl alcohols having 1 to 10 carbon atoms and acrylic acid, and acrylonitrile (hereinafter sometimes simply referred to as "unsaturated compound") are subjected to a Michael addition reaction in the presence of a base to obtain compound (2) represented by the following formula (2).

[0035] HO-(R １ -O) ｘ -H (1) (In formula (1), R １ x represents a divalent hydrocarbon group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms. x is an integer from 1 to 20. (R １ R in x structural units represented by -O) １ They may all be the same, or some or all of them may be different.

[0036] R ２ -CH ２ CH ２ -O-(R １ -O) ｘ -CH ２ CH ２ -R ２ (2) (In formula (2), R １ And x are the same as in equation (1). R ２ is -C(=O)-OR ３ (R ３ represents an alkyl group with 1 to 10 carbon atoms. ) or a cyano group. Two R ２ They may be the same or they may be different.

[0037] R in diol compound (1) １ R represents a divalent hydrocarbon group with 1 to 10 carbon atoms. １ In this case, some or all of the hydrogen atoms may be substituted with fluorine atoms. １ This is determined by appropriately selecting the diol compound (1) according to the structure of the target fluorine-containing ester compound. １The number of carbon atoms is preferably 1 to 8, and more preferably 1 to 6. １ This may be a straight-chain hydrocarbon group or a branched hydrocarbon group.

[0038] In formula (1), x is an integer from 1 to 20. Due to the target molecular weight of the final product, x is preferably an integer from 1 to 15, more preferably an integer from 1 to 10, and even more preferably an integer from 2 to 8.

[0039] The (R) of the diol compound (1) １ R in x structural units represented by -O) １ They may all be the same, or they may be different in some or all. (R １ R in x structural units represented by -O) １ If at least some of them are different, there are no particular restrictions on the order in which each structural unit is arranged.

[0040] x R atoms in diol compound (1) １ Each is independent of the other, -CH ２ -ien-CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -ien-CH ２ CH (CH ３ ) -, -CH ２ CH ２ CH ２ CH ２ -, -CF ２ -, -CF ２ CF ２ -, -CF ２ CF ２ CF ２ -, -CF (CF ３ ) CF ２ -, -CF ２ CF (CF ３ ) -, -CF ２ CF ２ CF ２ CF ２ -, -CF ２ CH ２ -ien-CH２ CF ２ -, -CF ２ CF ２ CH ２ -ien-CH ２ CF ２ CF ２ -, -CF ２ CF ２ CF ２ CH ２ -, and -CH ２ CF ２ CF ２ CF ２ It is preferable that the group is selected from the group consisting of -. The above group has a left-hand bond (R １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (R １ -Bonds to the oxygen atom in (O). x R in diol compound (1) １ It is preferable that each of these groups is independently one of the above-mentioned groups, as this results in a method for producing fluorine-containing ester compounds with good reproducibility.

[0041] Diol compound (1) specifically consists of x R atoms in formula (1). １ All are identical, -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -ien-CH ２ CH (CH ３ ) -, -CH ２ CH ２ CH ２ CH ２ It is preferable that it be one selected from the group consisting of -. The reason is that the raw materials for the diol compound (1) are relatively easy to obtain. Also, x R １ All are identical, -CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -ien-CH ２ CH (CH ３ ) -, -CH ２ CH ２CH ２ CH ２ It is more preferable that it be one of the types selected from the group consisting of -.

[0042] Furthermore, the diol compound (1) specifically consists of x R atoms in formula (1). １ Each of them independently, -CH(CH ３ )CH ２ - and -CH ２ CH (CH ３ It is also preferable to select from the group consisting of ) -. The reason is that the raw materials for the diol compound (1) are relatively easy to obtain. x R １ Each of them independently, -CH(CH ３ )CH ２ - and -CH ２ CH (CH ３ The diol compound (1) selected from the group consisting of ) means polypropylene glycol, which may be a mixture of isomers.

[0043] The diol compound (1) may be a compound containing a perfluoropolyether chain. Specifically, the diol compound (1) may be, for example, HO-CH ２ CF ２ O(CF) ２ CF ２ O) ｍ (CF ２ O) ｎ CF ２ CH ２ The compound may also be an O-H (where m and n represent the degree of polymerization; m is an integer from 1 to 15, and n is an integer from 0 to 15; the sum of m and n is from 1 to 18). In this case, the fluorine-containing ester compound produced by the production method of this embodiment has a skeleton (-O-CF) derived from the structural unit of a compound containing a perfluoropolyether chain, which is a diol compound (1). ２ CF ２ O(CF) ２ CF ２ O) ｍ (CF ２ O) ｎ CF ２ CF ２ -CF ２ CF ２- A linking group consisting of is attached. Therefore, the method for producing the fluorine-containing ester compound of this embodiment is to extend the perfluoropolyether chain of the diol compound (1) to form a structure (-CF ２ CF ２ -O-CF ２ CF ２ O(CF) ２ CF ２ O) ｍ (CF ２ O) ｎ CF ２ CF ２ O-CF ２ CF ２ It can be used as a method for producing compounds having -.

[0044] As the diol compound (1), a commercially available product may be used, or one synthesized by a conventionally known method may be used.

[0045] The unsaturated compound to be reacted with the diol compound (1) is at least one selected from the group consisting of alkyl acrylates, which are ester compounds of an alkyl alcohol having 1 to 10 carbon atoms and acrylic acid, and acrylonitrile. Therefore, as the unsaturated compound, only alkyl acrylates or only acrylonitrile may be used, or both alkyl acrylates and acrylonitrile may be used.

[0046] As alkyl alcohols having 1 to 10 carbon atoms used as raw materials for alkyl acrylates, secondary or tertiary alcohols having 4 to 10 carbon atoms are preferred, and tertiary alcohols having 4 to 10 carbon atoms are more preferred. Specifically, examples of alkyl acrylates include tert-butyl acrylate and methyl acrylate, with tert-butyl acrylate being preferred. This is because, when the unsaturated compound is tert-butyl acrylate, the bulky substituent such as tert-butyl suppresses the transesterification reaction, which is a side reaction of the Michael addition reaction in step (A).

[0047] The two Rs in compound (2) obtained by the Michael addition reaction in step (A-1) ２These are -C (=O) - OR ３ (R ３ represents an alkyl group having 1 to 10 carbon atoms. ) or a cyano group, with two R ２ However, both are -C (=O) - OR ３ Preferably, one or both are cyano groups, and this is determined by the type of unsaturated compound.

[0048] When only alkyl acrylate is used as the unsaturated compound, R in compound (2) ２ is -C(=O)-OR ３ (R ３ represents an alkyl group having 1 to 10 carbon atoms. ) In this case, R ２ R contained within ３ This corresponds to the alkyl group having 1 to 10 carbon atoms in the alkyl acrylate used as an unsaturated compound. Specifically, R ２ R contained within ３ Examples include tert-butyl groups and methyl groups.

[0049] Furthermore, when only acrylonitrile is used as the unsaturated compound, R in compound (2) obtained by the Michael addition reaction in step (A-1) ２ This becomes -CN.

[0050] Two Rs in compound (2) ２ The two Rs may be the same or different, but it is preferable that they be the same. ２ Compound (2) having the same properties can be produced, for example, by using only one type of compound as an unsaturated compound. Also, two R ２ Compound (2) with different properties can be produced, for example, by using two or more compounds as unsaturated compounds. When two or more compounds are used as unsaturated compounds, the Michael addition reaction in step (A-1) produces two R compounds that make up compound (2). ２ Compounds that are the same and two R ２Multiple compounds are produced, each containing different compounds. Therefore, when using two or more unsaturated compounds, a separation step is necessary to separate the target compound from the multiple compounds produced.

[0051] For the Michael addition reaction in step (A-1), it is preferable to use at least one base selected from the group consisting of potassium tert-butoxide, sodium hydride, and potassium hydroxide. Among these, potassium tert-butoxide or sodium hydride is preferred because it can suppress side reactions after acting as a base in the Michael addition reaction between the diol compound (1) and the unsaturated compound.

[0052] When using an alkyl acrylate as the unsaturated compound in the Michael addition reaction of step (A-1), it is also preferable to use a compound containing an alkyl group found in the alkyl acrylate. In this case, side reactions in the Michael addition reaction between the diol compound (1) and the alkyl acrylate, in which the alkyl group caused by the base generates byproducts, can be suppressed more effectively.

[0053] In step (A-1), the diol compound (1) and the unsaturated compound may be reacted in a solvent or without a solvent. Examples of solvents include tetrahydrofuran.

[0054] In step (A-1), the molar ratio of the unsaturated compound to the diol compound (1) (unsaturated compound) / (diol compound) is preferably 2.0 to 5.0, more preferably 2.0 to 3.5, and particularly preferably 2.1 to 3.0. This is because a molar ratio of 2.0 or higher for the unsaturated compound to the diol compound (1) facilitates the addition reaction between the diol compound (1) and the unsaturated compound. Furthermore, a molar ratio of 5.0 or lower for the unsaturated compound to the diol compound (1) suppresses side reactions in the addition reaction between the diol compound (1) and the unsaturated compound.

[0055] In step (A-1), the molar ratio of the base to the diol compound (1) (base) / (diol compound) is preferably 0.001 to 2, more preferably 0.01 to 1, and even more preferably 0.01 to 0.5. This is because a molar ratio of the base to the diol compound (1) of 0.001 or higher facilitates the addition reaction between the diol compound (1) and the unsaturated compound. Furthermore, a molar ratio of the base to the diol compound (1) of 2 or lower suppresses side reactions after the base has acted as a base.

[0056] In step (A-1), it is preferable to react the unsaturated compound by dropwise adding it to a mixture obtained by mixing the diol compound (1) and a base at a predetermined flow rate and temperature. The temperature of the reaction solution (the mixture to which the unsaturated compound has been added) while the unsaturated compound is being added dropwise can be appropriately determined depending on the type and amount of the diol compound (1), the base, and the unsaturated compound. The temperature of the reaction solution while the unsaturated compound is being added dropwise is preferably -20°C to 60°C, and more preferably -10°C to 50°C.

[0057] In step (A-1), the reaction solution obtained by adding an unsaturated compound dropwise to a mixture of diol compound (1) and a base may be reacted at the same temperature as the mixture while the unsaturated compound was being added dropwise, or it may be reacted at a higher temperature than the temperature during which the unsaturated compound was being added dropwise.

[0058] The reaction temperature in step (A-1) (the temperature of the reaction solution from the completion of the dropwise addition of the unsaturated compound to the mixture until the reaction is stopped) can be appropriately determined depending on the type and amount of the diol compound (1), the base, and the unsaturated compound. The reaction temperature in step (A-1) is preferably -30°C to 100°C, more preferably 0°C to 70°C, and even more preferably 20°C to 70°C. This is because a reaction temperature of -30°C or higher facilitates the Michael addition reaction between the diol compound (1) and the unsaturated compound. Also, a reaction temperature of 100°C or lower suppresses side reactions.

[0059] The reaction temperature in step (A-1) may be constant during the period from the completion of the dropwise addition of the unsaturated compound to the mixed solution to the termination of the reaction (from the start of the reaction to the end of the reaction), or may be changed within the range of -30°C to 100°C as the reaction progresses. When the reaction temperature is changed as the reaction progresses, it is preferable to raise the temperature stepwise or continuously from the start of the reaction to the end of the reaction. This allows effective promotion of the Michael addition reaction between the diol compound (1) and the unsaturated compound, and enables production of the compound (2) in a high yield.

[0060] The reaction time of step (A-1) (from the start of the reaction to the end of the reaction) can be appropriately determined according to the types and amounts of the diol compound (1), the base, and the unsaturated compound. The reaction time of step (A-1) is preferably from 1 hour to 200 hours, more preferably from 5 hours to 100 hours, and even more preferably from 10 hours to 50 hours. The Michael addition reaction between the diol compound (1) and the unsaturated compound is an equilibrium reaction. When the reaction time is 1 hour or longer, the above addition reaction proceeds sufficiently. When the reaction time is 200 hours or less, side reactions in the Michael addition reaction between the diol compound (1) and the unsaturated compound can be suppressed, and the fluorine-containing ester compound can be efficiently produced in a short time.

[0061] In step (A-1), when the reaction solution is prepared by dropwise adding the unsaturated compound to the mixed solution containing the diol compound (1) and the base, the reaction time of step (A-1) is calculated with the point of time when the dropwise addition of the unsaturated compound to the mixed solution is completed defined as 0 minute.

[0062] [Step (A-2)] Step (A-2) is a step of converting the compound (2) obtained in step (A-1) into a diester compound (2a) having both terminals represented by the following formula (2a).

[0063] R ４ O-C(=O)-CH ２ CH ２ -O-(R １ -O) ｘ -CH ２ CH ２ -C(=O)-OR ４ (2a) (in formula (2a), R １And x are the same as in equation (1). R ４ The R represents an alkyl group with 1 to 10 carbon atoms. ４ They may be the same or they may be different.

[0064] R in the terminal ester compound (2a) obtained in step (A-2) ４ R is an alkyl group having 1 to 10 carbon atoms. ４ For example, -CH ３ ien-CH ２ CH ３ ien-CH ２ CH ２ CH ３ These are some examples. Among these, R ４ is, -CH ３ It is preferable that this be the case.

[0065] Step (A-2) is R in equation (2). ２ If it is not a cyano group, it may be omitted. R in formula (2) ２ If it is not a cyano group (in other words, if the unsaturated compound in step (A-1) is an alkyl acrylate), then compound (2) is R ２ is -C(=O)-OR ３ It is a terminally ester compound.

[0066] R in equation (2) ２ If the group is not a cyano group and step (A-2) is omitted, then R in compound (2) represented by formula (2) ２ is -C(=O)-OR ３ Therefore, compound (2) is the same compound as the terminal ester compound (2a). That is, R ３ is R ４ It is identical to R in equation (2). ２ If it is not a cyano group and step (A-2) is not omitted, R ３ and R ４ These are different alkyl groups. Therefore, compound (2) and the terminal ester compound (2a) are different compounds.

[0067] If the unsaturated compound is an alkyl acrylate and step (A-2) is not omitted, step (A-2) is a transesterification step (A-2-1) in which compound (2) is transesterified to obtain a terminal ester compound (2a) different from compound (2).

[0068] If the unsaturated compound in step (A-1) is acrylonitrile, then R in compound (2) ２ Since is -CN, step (A-2) is performed as an alcohol decomposition step (A-2-2) to obtain a double-terminated ester compound (2a) by alcohol decomposition of the cyano group of compound (2).

[0069] "Transesterification process (A-2-1)" When an alkyl acrylate having an alkyl group with 1 to 10 carbon atoms is used as the unsaturated compound in process (A-1), the R in compound (2) ２ is -C(=O)-OR ３ (R ３ This represents an alkyl group with 1 to 10 carbon atoms.

[0070] The transesterification reaction in the transesterification step (A-2-1) is represented by the following chemical equation (I). In chemical equation (I), compound (2I) represented by the following equation (2I) is obtained in step (A-1) when the unsaturated compound is an alkyl acrylate. ２ is -C(=O)-OR ３ Compound (2) is R. ４ -OH(R) ４ R represents an alkyl group with 1 to 10 carbon atoms. ４ is R ３ It is a different alkyl group from ). ) is an alkyl alcohol used in transesterification reactions. The compound represented by formula (2a) is the terminal ester compound (2a) produced by the transesterification reaction.

[0071] (In formula (I), R １ And x are the same as in equation (1). R ３ The R represents an alkyl group with 1 to 10 carbon atoms. ３They may be the same or they may be different. ４ The R represents an alkyl group with 1 to 10 carbon atoms. ４ They may be the same or they may be different. ３ and R ４ These are different alkyl groups.

[0072] When performing the transesterification process (A-2-1), R ３ and R ４ These are different alkyl groups. R of both terminal ester compounds (2a) ４ The number of carbon atoms in the alkyl group represented by is R of compound (2I). ３ It is preferable that the number of carbon atoms is less than the number of carbon atoms in the alkyl group represented by the given symbol. This is because it allows for a reduction in the amount of fluorine compound used for fluorination in step (B) described later.

[0073] As shown in chemical equation (I), the transesterification step (A-2-1) involves converting compound (2I) under acidic conditions to R ４ Preferably, the step involves transesterifying compound (2I) by reacting it with an alkyl alcohol represented by -OH.

[0074] In the transesterification process (A-2-1), R ４ As an alkyl alcohol represented by -OH, R ４ However, R in compound (2) ３ One or more monohydric alkyl alcohols, which are alkyl groups having 1 to 10 carbon atoms different from those specified, can be used. When two or more alkyl alcohols are used, the two R's in formula (2a) ４ These will be different alkyl groups.

[0075] The alkyl alcohol is preferably one with a small number of carbon atoms and a small number of substituted hydrogen atoms, in order to reduce the amount of fluorine gas consumed in the fluorination reaction in the next step (B). Specific examples of such alkyl alcohols include methanol, ethanol, and n-propanol, with methanol being even more preferred.

[0076] Examples of acids that can be used as catalysts in the transesterification reaction of compound (2I) include hydrochloric acid, sulfuric acid, p-toluenesulfonic acid, and hydrogen chloride (alcohol solution). In the transesterification reaction of compound (2I), compound (2I) and the alkyl alcohol may be reacted in a solvent or without a solvent. Examples of solvents include tetrahydrofuran.

[0077] The molar ratio of the alkyl alcohol to compound (2I), (alcohol) / (compound (2I)), is preferably 2 to 200, more preferably 5 to 150, and even more preferably 10 to 100. This is because the transesterification reaction of compound (2I) proceeds more easily when the molar ratio of the alkyl alcohol to compound (2I) is within the above range.

[0078] The molar ratio of acid to compound (2I), (acid) / (compound (2I)), is preferably 1 to 40, more preferably 1.5 to 20, and even more preferably 2 to 10. A molar ratio of acid to compound (2I) of 1 or more allows the acid's catalytic function to sufficiently promote the transesterification reaction of compound (2I). Furthermore, a molar ratio of acid to compound (2I) of 40 or less allows for relatively easy post-treatment after the transesterification reaction of compound (2I).

[0079] The transesterification reaction of compound (2I) may be carried out by reacting compound (2I) with a commercially available hydrogen chloride / methanol solution.

[0080] The reaction temperature in the transesterification step (A-2-1) is preferably 0°C to 80°C, more preferably 10°C to 70°C, and even more preferably 15°C to 60°C. This is because a reaction temperature of 0°C or higher facilitates the transesterification reaction of compound (2I). Furthermore, a reaction temperature of 80°C or lower suppresses side reactions in the transesterification reaction of compound (2I).

[0081] The reaction time in the transesterification step (A-2-1) is preferably 1 hour to 500 hours, more preferably 2 hours to 300 hours, and even more preferably 5 hours to 100 hours. A reaction time of 1 hour or more allows the transesterification reaction of compound (2I) to proceed sufficiently. A reaction time of 500 hours or less suppresses side reactions in the transesterification reaction of compound (2I) and allows for the efficient production of the terminal ester compound (2a) in a short time.

[0082] The reaction in the transesterification step (A-2-1) can be quenched (stopped) by adding, for example, at least one compound selected from the group consisting of trisodium citrate and sodium bicarbonate to the reaction mixture. For post-quenching treatment, for example, methods such as recovering the organic layer by liquid-liquid separation of the reaction mixture or removing salts by filtration of the reaction mixture can be used.

[0083] If a transesterification step (A-2-1) is performed in step (A-2), then in step (B), the terminal ester compound (2a) obtained by the transesterification step (A-2-1) is fluorinated.

[0084] "Alcohol decomposition step (A-2-2)" When acrylonitrile is used as the unsaturated compound in step (A-1), R in compound (2) ２ This becomes a cyano group (-CN). The alcohol decomposition step (A-2-2) in step (A-2) is a step in which the cyano group located at the terminal end of compound (2) is decomposed with alcohol to obtain the terminal ester compound (2a).

[0085] The alcohol decomposition reaction (Pinner reaction) in the alcohol decomposition step (A-2-2) is presumed to be the reaction shown by chemical equations (II) and (III) below.

[0086] In chemical reaction equation (II), the compound (2II) represented by the following formula (2II) is obtained in step (A-1) when the unsaturated compound is acrylonitrile, R ２However, it is compound (2) which is -CN. ４ -OH(R) ４ R represents an alkyl group with 1 to 10 carbon atoms. ４ is R ３ This is a different alkyl group from .) is an alkyl alcohol used in the alcohol decomposition reaction. The following formula (2b) is the intermediate compound (2b) produced in the alcohol decomposition reaction. In chemical reaction equations (II) and (III), the compound represented by the following formula (2c) is the intermediate compound (2c) produced in the alcohol decomposition reaction and is a salt of the intermediate compound (2b). In chemical reaction equation (III), the compound represented by formula (2d) is the by-product (2d) produced by the alcohol decomposition reaction. The compound represented by formula (2a) is the terminal ester compound (2a) produced by the alcohol decomposition reaction.

[0087] (In formula (II), R １ And x are the same as in equation (1). R ４ The R represents an alkyl group with 1 to 10 carbon atoms. ４ (These may be the same or different.) (In equation (III), R １ And x are the same as in equation (1). R ４ The R represents an alkyl group with 1 to 10 carbon atoms. ４ They may be the same or they may be different.

[0088] As shown in chemical equation (II), the alcohol decomposition step (A-2-2) is R ２ A compound (2II) in which is -CN is prepared under acidic conditions, R ４ Preferably, the step involves alcoholic decomposition of compound (2II) by reacting it with an alkyl alcohol represented by -OH.

[0089] In the alcohol decomposition step (A-2-2), R ４ As the alkyl alcohol represented by -OH, one or more monohydric alkyl alcohols having 1 to 10 carbon atoms can be used. When two or more alkyl alcohols are used, the two R's in formula (2a)４ This will be a different alkyl group. It can be used in the alcohol decomposition step (A-2-2), R ４ The alkyl alcohol represented by -OH can be used in the transesterification step (A-2-1), R ４ Examples include alkyl alcohols represented by -OH.

[0090] The alkyl alcohol is preferably one with a small number of carbon atoms and a small number of substituted hydrogen atoms, in order to reduce the amount of fluorine gas consumed in the fluorination reaction in the next step (B). Specific examples of such alkyl alcohols include methanol, ethanol, and n-propanol, with methanol being even more preferred.

[0091] In the alcoholic decomposition reaction of compound (2II), examples of acids that can be used include hydrochloric acid and sulfuric acid. Among these, sulfuric acid is preferred because it is non-volatile and easy to handle. In the alcoholic decomposition reaction of compound (2II), compound (2II) and the alcohol may be reacted in a solvent or without a solvent. Examples of solvents include tetrahydrofuran.

[0092] The molar ratio of alkyl alcohol to compound (2II) (alcohol / compound (2II)) is preferably 2 to 150, more preferably 4 to 100, and even more preferably 5 to 75. This is because when the molar ratio of alcohol to compound (2II) is within the above range, the alcohol decomposition reaction of compound (2II) proceeds more easily.

[0093] The molar ratio of acid to compound (2II) (acid) / (compound (2II)) is preferably 2 to 30, more preferably 2.51 to 20, and even more preferably 3 to 10. This is because when the molar ratio of acid to compound (2II) is within the above range, the alcohol decomposition reaction of compound (2II) proceeds more easily.

[0094] The reaction temperature in the alcohol decomposition step (A-2-2) is preferably 40°C to 150°C, more preferably 60°C to 130°C, and even more preferably 70°C to 110°C. This is because a reaction temperature of 40°C or higher facilitates the alcohol decomposition reaction of compound (2II). Furthermore, a reaction temperature of 150°C or lower suppresses side reactions in the alcohol decomposition reaction of compound (2II).

[0095] The reaction time in the alcohol decomposition step (A-2-2) is preferably 1 hour to 200 hours, more preferably 5 hours to 150 hours, and even more preferably 10 hours to 100 hours. A reaction time of 1 hour or more allows the alcohol decomposition reaction of compound (2II) to proceed sufficiently. A reaction time of 200 hours or less suppresses side reactions in the alcohol decomposition reaction of compound (2II) and allows for the efficient production of the terminal ester compound (2a) in a short time.

[0096] If the alcohol decomposition step (A-2-2) is performed in step (A-2), the terminal ester compound (2a) obtained by performing the alcohol decomposition step (A-2-2) is fluorinated in step (B).

[0097] <Step (B)> Step (B) is a "fluorination step (B-1)" in which the two terminal ester compounds (2a) are fluorinated to obtain an intermediate compound (3a) represented by the following formula (3a), and then the intermediate compound (3a) is R ５ -OH(R) ５ The process includes an "esterification step (B-2)" in which an alkyl alcohol represented by ) is reacted with an alkyl alcohol represented by the following formula (3) to obtain a fluorine-containing ester compound (3) represented by the following formula (3).

[0098] R ４ OC(=O)-CH ２ CH ２ -O-(R １ -O) ｘ -CH ２ CH ２ -C (=O) -OR ４(2a) →FC(=O)-CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -C(=O)-F (3a) →R ５ OC(=O)-CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -C (=O) -OR ５ (3) (In formula (3a), Rf １ R in equation (1) １ This represents a divalent perfluorohydrocarbon group in which a hydrogen atom is replaced by a fluorine atom. x is the same as in formula (1). ) (In formula (3), Rf １ R in equation (1) １ R represents a divalent perfluorocarbon group in which a hydrogen atom is replaced by a fluorine atom. ５ The R represents an alkyl group with 1 to 10 carbon atoms. ５ x may be the same or different. x is the same as in equation (1).

[0099] In the fluorination step (B-1), the R of the terminal ester compound (2a) １ The hydrogen atom of -CH ２ CH ２ - Hydrogen atom, R ４ The hydrogen atoms are simultaneously replaced by fluorine atoms. The terminal "-CF" is replaced by fluorine atoms. ２ CF ２ -C(=O)-ORf ４ (Rf ４ R in equation (2a) ４ This represents an alkyl group in which a hydrogen atom is replaced by a fluorine atom. ) is very unstable. Therefore, in the reaction system, the carbonyl fluoride: "F-C(=O)-F" is immediately eliminated, resulting in "-CF ２ CF ２ It changes to -C(=O)-F, and intermediate compound (3a) is produced.

[0100] In step (B), R in equation (2) ２If the compound is not a cyano group and step (A-2) is omitted, the compound (2) produced in step (A-1) is used as the terminal ester of the terminal ester compound (2a). This is because the compound (2) produced in step (A-1) has the same structure as the terminal ester compound (2a).

[0101] [Fluorination Process (B-1)] The fluorination process (B-1) is a process in which the terminal ester compound (2a) (hereinafter sometimes referred to as the "fluorination raw material") is fluorinated to produce an intermediate compound (3a) represented by formula (3a).

[0102] In the method for producing fluorine-containing ester compounds of this embodiment, the fluorination step (B-1) may consist only of a first fluorination step (B-1-1) in which the fluorination raw material is fluorinated using an inert gas and a fluorine gas, or, after performing the first fluorination step (B-1-1), a second fluorination step (B-1-2) may be performed in which the fluorination raw material fluorinated in the first fluorination step (B-1-1) is further fluorinated using an inert gas, a fluorine gas and a perhalogen unsaturated hydrocarbon compound.

[0103] "First Fluorination Step (B-1-1)" The first fluorination step (B-1-1) is preferably carried out by introducing a fluorination raw material, an inert gas, a fluorine gas, and a solvent into a reactor to fluorinate the fluorination raw material.

[0104] In the first fluorination step (B-1-1), the total equivalent amount of fluorine gas introduced into the reactor is preferably 1.0 to 5.0 equivalents, more preferably 1.1 to 3.0 equivalents, relative to the number of moles of hydrogen atoms contained in the fluorination raw material. If the equivalent amount of fluorine gas is 1.0 equivalent or more relative to the number of moles of hydrogen atoms contained in the fluorination raw material, the fluorination of the fluorination raw material proceeds more easily. If the equivalent amount of fluorine gas is 5.0 equivalents or less relative to the number of moles of hydrogen atoms contained in the fluorination raw material, the generation of fluorine gas that is wasted without being consumed in the fluorination reaction can be suppressed. The fluorination reaction is R - H + F ２ →R - F + HF, therefore fluorine gas F ２ This amounts to 1 equivalent for each hydrogen atom.

[0105] In the first fluorination step (B-1-1), the concentration of fluorine gas flowing through the reactor is preferably 1% to 30% by volume, more preferably 10% to 20% by volume, based on the total amount of flowing gas (fluorine gas + inert gas). If the fluorine gas concentration is 1% by volume or higher, it is possible to prevent a decrease in the reaction rate of the fluorination reaction and a prolonged reaction time. If the fluorine gas concentration is 30% by volume or lower, it is possible to prevent the fluorination reaction from running out of control or the occurrence of side reactions in the fluorination reaction.

[0106] In the first fluorination step (B-1-1), the pressure inside the reactor when introducing fluorine gas into the reactor is preferably 0.08 MPa to 0.12 MPa, and more preferably atmospheric pressure (0.1 MPa) to 0.115 MPa. If the pressure is 0.08 MPa or higher, it is possible to prevent the reaction rate of the fluorination reaction from decreasing and the reaction time from becoming longer. If the pressure is 0.12 MPa or lower, it is possible to prevent the fluorination reaction from running out of control or the occurrence of side reactions in the fluorination reaction.

[0107] In the first fluorination step (B-1-1), the inert gas used in the fluorination reaction is preferably selected from nitrogen gas, helium gas, or argon gas due to its availability and ease of handling. The inert gas is circulated in the reactor so that the concentration of the fluorine gas circulating in the reactor is within the above range. The inert gas and fluorine gas may be introduced into the reactor by separate systems. Alternatively, the fluorine gas may be diluted with the inert gas beforehand to form a mixed gas before being introduced into the reactor.

[0108] In the first fluorination step (B-1-1), the solvent used in the fluorination reaction is not particularly limited, but it is preferably a solvent with high solubility of the fluorination raw materials and products, and more preferably a solvent that does not react with the fluorination raw materials, products, and fluorine gas. Specifically, a solvent in which hydrogen atoms are completely substituted with halogens and which does not contain carbon-carbon unsaturated bonds is preferred. A solvent that is completely substituted with halogens and does not contain carbon-carbon unsaturated bonds does not contain C-H bonds or carbon-carbon unsaturated bonds. Therefore, the C-H bonds or carbon-carbon unsaturated bonds in the solvent do not react with the fluorine gas, thus preventing an increase in the amount of fluorine gas used and a rise in temperature due to the heat of reaction. Furthermore, it is preferable that the decomposition reaction of the fluorination raw materials by hydrogen fluoride, which is generated when C-H bonds react with fluorine gas, does not occur.

[0109] Solvents used in fluorination reactions include perhalogenal alkanes, perhalogenal polyethers, perhalogenated carboxylic acids, or their anhydrides. The solvent may be used alone or in combination of two or more.

[0110] As perhalogenal alkanes, those having 2 to 8 carbon atoms are preferred. From the viewpoint of solubility of the fluorination raw material, perhalogenal alkanes containing both fluorine and chlorine atoms are more preferred, such as dichlorotetrafluoroethane, trichlorotrifluoroethane, dichlorohexafluoropropane, and tetrachlorohexafluorobutane. Among these, tetrachlorohexafluorobutane is preferred because the boiling point of the solvent is not too low.

[0111] Examples of commercially available perhalogen polyethers include DEMNUM® from Daikin Industries, Ltd., FLUORINERT® from 3M, GALDEN® from Solvay Specialty Polymers, and KRYTOX® from Chemours. Examples of perhalogen carboxylic acids or their anhydrides include trifluoroacetic acid and trifluoroacetic anhydride.

[0112] In the first fluorination step (B-1-1), it is preferable to introduce a solvent into the reactor before introducing the fluorination raw material into the reactor. Furthermore, it is preferable to circulate an inert gas and fluorine gas through the reactor before introducing the fluorination raw material into the reactor, thereby saturating the solvent previously introduced into the reactor with fluorine gas.

[0113] In the first fluorination step (B-1-1), it is preferable to introduce the fluorination raw material into the reactor by preparing a raw material solution obtained by dissolving the fluorination raw material in a solvent, and supplying the raw material solution into the reactor while circulating an inert gas and fluorine gas through the reactor. The solvent used to dissolve the fluorination raw material can be one of the solvents exemplified for use in the fluorination reaction, and it is preferable that it be the same solvent used for the fluorination reaction.

[0114] The concentration of the fluorinating raw material in the reactor can be adjusted according to the solubility of the fluorinating raw material in the solvent, but is preferably 0 to 3.0 mol / L, and more preferably 0 to 1.5 mol / L. While not particularly limited, the concentration of the fluorinating raw material in the reactor may be 0.01 to 3.0 mol / L or 0.01 to 1.5 mol / L. The supply rate of the raw material solution to the reactor can be adjusted according to the concentration and flow rate of the fluorine gas circulating in the reactor, so that the equivalent amount of fluorine gas to the fluorinating raw material falls within the above range.

[0115] In the first fluorination step (B-1-1), the temperature inside the reactor when fluorine gas is introduced is preferably -30 to 60°C, more preferably -20 to 30°C. In one embodiment, the temperature inside the reactor when fluorine gas is introduced is preferably 20 to 60°C, more preferably 20 to 30°C. The temperature inside the reactor is preferably above the boiling point of hydrogen fluoride (20°C) in order to efficiently remove hydrogen fluoride produced as a by-product of fluorination. When the temperature is 20°C or higher, hydrogen fluoride does not remain, and decomposition reactions of the raw materials are less likely to occur, which is preferable. Also, when the temperature is 60°C or lower, it is possible to prevent the fluorination reaction from running out of control or the occurrence of side reactions in the fluorination reaction.

[0116] In another embodiment, the temperature inside the reactor when introducing fluorine gas may be -30 to 20°C or -20 to 0°C. In this case, in order to efficiently remove hydrogen fluoride produced as a by-product of fluorination, it is preferable to increase the dilution ratio of an inert gas such as nitrogen gas to the fluorine gas, or to use a hydrogen fluoride scavenger. Examples of hydrogen fluoride scavengers include alkali metal fluorides such as sodium fluoride and potassium fluoride, and organic bases such as trialkylamines.

[0117] In the first fluorination step (B-1-1), it is preferable to use a reactor with high pressure resistance, and an autoclave is usually used. The material of the reactor is not particularly limited, but a stainless steel or nickel metal container, or a container coated with fluororesin, is preferred because it does not react easily with fluorine gas.

[0118] The fluorination reaction in the first fluorination step (B-1-1) can be carried out using either a flow-through or batch method. In the flow-through method, the flow rate of the raw material solution supplied to the reactor is not particularly limited, but is adjusted according to the equivalent amount of fluorine gas relative to the fluorinating raw material, the size of the reactor, and the pressure inside the reactor. The flow rate of the raw material solution supplied to the reactor is preferably 0.5 to 100 mmol / min, more preferably 2 to 30 mmol / min, based on the number of moles of hydrogen atoms contained in the fluorinating raw material. In the batch method, it is sufficient to introduce pressure-controlled fluorine gas from the reactor inlet in the amount consumed in the reaction.

[0119] "Second Fluorination Step (B-1-2)" The second fluorination step (B-1-2) is a step in which the fluorinating raw material fluorinated in the first fluorination step (B-1-1) is further fluorinated. It is preferable to carry out this step by introducing an inert gas, fluorine gas, a perhalogen unsaturated hydrocarbon compound, and a solvent into the reactor in which the fluorinating raw material fluorinated in the first fluorination step (B-1-1) was carried out, and further fluorinating the fluorinating raw material fluorinated in the first fluorination reaction. In the later stages of the first fluorination step (B-1-1), the reaction rate of the fluorination reaction of the fluorinating raw material may decrease. For this reason, it is preferable to carry out the second fluorination step (B-1-2) after the first fluorination step (B-1-1).

[0120] In the second fluorination step (B-1-2), it is preferable to further fluorinate the fluorinated raw materials in the first fluorination reaction by introducing a perhalogen unsaturated hydrocarbon compound into the reactor that carried out the first fluorination step (B-1-1), while circulating an inert gas and fluorine gas. When a perhalogen unsaturated hydrocarbon compound is introduced into the reactor after the first fluorination step (B-1-1), the unsaturated bonds in the perhalogen unsaturated hydrocarbon compound react with fluorine gas, generating fluorine radicals. The generated fluorine radicals react with the fluorinated raw materials that were not fluorinated in the first fluorination step (B-1-1), promoting fluorination and accelerating the fluorination reaction. In the second fluorination step (B-1-2), since a perhalogen unsaturated hydrocarbon compound is used, it is preferable that fluorine gas is not consumed for fluorinating the C-H bonds in the unsaturated hydrocarbon compound, as is the case when using unsaturated hydrocarbon compounds having C-H bonds such as benzene, and the amount of fluorine gas used does not increase.

[0121] In the second fluorination step (B-1-2), the inert gas circulated when introducing the perhalogen unsaturated hydrocarbon compound into the reactor may be one of the inert gases exemplified in the first fluorination step (B-1-1) used for the fluorination reaction. In the second fluorination step (B-1-2), it is preferable to adjust the flow rates of the inert gas and fluorine gas so that the concentration of the fluorine gas circulated into the reactor is within the range exemplified in the first fluorination step (B-1-1) used for the fluorine gas circulated into the reactor.

[0122] Examples of perhalogen unsaturated hydrocarbon compounds include hexafluorobenzene, hexachlorobenzene, chloropentafluorobenzene, trichlorotrifluorobenzene, decafluorobiphenyl, octafluoronaphthalene, tetrachloroethylene, trichlorofluoroethylene, dichlorodifluoroethylene, trichlorotrifluoropropene, and dichlorotetrafluoropropene. Among these, hexafluorobenzene is particularly preferred because it is readily available and easy to handle.

[0123] As a method for introducing perhalogen-unsaturated hydrocarbon compounds, it is preferable to dissolve the perhalogen-unsaturated hydrocarbon compound in a solvent and introduce a fixed amount into the reactor. The amount of perhalogen-unsaturated hydrocarbon compound flowing is preferably 1 / 50 to 1 / 5 molar times, more preferably 1 / 30 to 1 / 10 molar times, of the amount of fluorine gas flowing, calculated in terms of the number of moles of unsaturated bonds in the perhalogen-unsaturated hydrocarbon compound. If the amount of perhalogen-unsaturated hydrocarbon compound flowing is 1 / 50 molar times or more, the fluorination reaction will not proceed slowly, and the reaction time will not be prolonged. If the amount of perhalogen-unsaturated hydrocarbon compound flowing is 1 / 5 molar time or less, it will be possible to prevent the fluorination reaction from running out of control or the occurrence of side reactions in the fluorination reaction.

[0124] In the second fluorination step (B-1-2), the pressure inside the reactor when the perhalogen unsaturated hydrocarbon compound is introduced is preferably 0.08 MPa to 0.12 MPa, more preferably atmospheric pressure (0.1 MPa) to 0.115 MPa. If the pressure is 0.08 MPa or higher, it is possible to prevent a decrease in the reaction rate of the fluorination reaction and a prolonged reaction time. If the pressure is 0.12 MPa or lower, it is possible to prevent the fluorination reaction from running out of control or the occurrence of side reactions in the fluorination reaction.

[0125] In the second fluorination step (B-1-2), the temperature inside the reactor when the perhalogen unsaturated hydrocarbon compound is introduced is preferably -30°C to 60°C, more preferably -20°C to 30°C. If the temperature is above -30°C, it is possible to prevent the reaction rate of the fluorination reaction from decreasing and the reaction time from becoming longer. If the temperature is below 60°C, it is possible to prevent the fluorination reaction from running out of control or the occurrence of side reactions in the fluorination reaction.

[0126] In the second fluorination step (B-1-2), it is preferable to use the same solvent as the solvent used in the first fluorination step (B-1-1). If a different solvent is used than that used in the first fluorination step (B-1-1), the solvent exemplified in the first fluorination step (B-1-1) can be used.

[0127] When a perhalogen unsaturated hydrocarbon compound is dissolved in a solvent and supplied to a reactor as a solution, the concentration of the perhalogen unsaturated hydrocarbon compound in the solution supplied to the reactor can be adjusted according to its solubility in the solvent, but is preferably 0.01 to 100 mol / L, and more preferably 0.1 to 10 mol / L, based on the number of moles of unsaturated bonds in the perhalogen unsaturated hydrocarbon compound.

[0128] [Esterification process (B-2)] In the esterification process (B-2), after the fluorination process (B-1), the intermediate compound (3a) produced in the fluorination process and R ５ -OH(R) ５The first step involves reacting an alkyl alcohol represented by (1 to 10 carbon atoms) with an alkyl alcohol to obtain a fluorine-containing ester compound (3) represented by formula (3).

[0129] The alkyl alcohol to be reacted with the intermediate compound (3a) is R ５ -OH(R) ５ R represents an alkyl group having 1 to 10 carbon atoms. It is an alcohol represented by . ５ The number of carbon atoms is preferably 1 to 6, and more preferably 1 to 4. Specifically, examples of alkyl alcohols include methanol, ethanol, and n-propanol. Among these, methanol is preferred.

[0130] The reaction temperature between the intermediate compound (3a) and the alkyl alcohol in the esterification step (B-2) is preferably -30°C to 60°C, more preferably -20°C to 30°C. This is because a reaction temperature of -30°C or higher facilitates the esterification of the intermediate compound (3a). Furthermore, a reaction temperature of 60°C or lower suppresses side reactions during the esterification of the intermediate compound (3a).

[0131] The reaction pressure between the intermediate compound (3a) and the alkyl alcohol in the esterification step (B-2) is preferably 0.08 MPa to 0.12 MPa, more preferably atmospheric pressure (0.1 MPa) to 0.115 MPa. This is because a reaction pressure of 0.08 MPa or higher facilitates the esterification of the intermediate compound (3a). Furthermore, a reaction pressure of 0.12 MPa or lower suppresses side reactions during the esterification of the intermediate compound (3a).

[0132] In the esterification step (B-2), the amount of alkyl alcohol used is preferably 2 to 10 equivalents, and more preferably 3 to 5 equivalents, relative to the number of moles at both ends of the intermediate compound (3a) that react with the alkyl alcohol (theoretical amount based on the number of moles of the fluorinated raw material). This is because if the amount of alkyl alcohol used is 2 equivalents or more relative to the number of moles of the intermediate compound (3a), the esterification of the intermediate compound (3a) proceeds more easily. Also, if the amount of alkyl alcohol used is 10 equivalents or less relative to the number of moles of the intermediate compound (3a), side reactions in the esterification of the intermediate compound (3a) can be suppressed.

[0133] Rf in the fluorine-containing ester compound (3) produced by the esterification step (B-2) １ R in equation (1) １ R in formula (1) represents a divalent perfluorocarbon group in which a hydrogen atom is replaced by a fluorine atom. １ If is a perfluorohydrocarbon group, then Rf in formula (3) １ R in equation (1) １ This may be the same as (a divalent hydrocarbon group having 1 to 10 carbon atoms, in which some or all of the hydrogen atoms may be replaced by fluorine atoms).

[0134] In equation (1), (R １ R in x structural units represented by -O) １ If some or all of the elements are different, Rf in the x structural units in formula (3) １ This is a corresponding structure. That is, (Rf １ Rf in x structural units represented by -O) １ They may all be the same, or they may be different in some or all ways.

[0135] Specifically, the fluorine-containing ester compound (3) is the x Rf in formula (3). １ All of them are identical, and x of the R in equation (1) １ All are identical, -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -, -CH(CH ３ )CH２ -ien-CH ２ CH (CH ３ ) -, -CH ２ CH ２ CH ２ CH ２ - (The left-hand joint is (R １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (R １ It is preferable that it be one selected from the group consisting of (bonded to the oxygen atom in -O). Furthermore, the fluorine-containing ester compound (3) is specifically the x Rf in formula (3). １ Each of them independently, -CH(CH ３ )CH ２ - and -CH ２ CH (CH ３ ) - (the left-hand joint is (Rf １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (Rf １ It is also preferable to select from the group consisting of (bonding to the oxygen atom in -O).

[0136] R in fluorine-containing ester compound (3) ５ R is an alkyl group having 1 to 10 carbon atoms. ５ For example, -CH ３ ien-CH ２ CH ３ ien-CH ２ CH ２ CH ３ These are some examples. Among these, R ５ CH ３ This is preferable. R in fluorine-containing ester compound (3) ５ In the esterification step (B-2), the alkyl alcohol (R) is reacted with the intermediate compound (3a). ５ This structure corresponds to the alkyl group of -OH.

[0137] Two R in fluorine-containing ester compound (3) ５ The two Rs may be the same or different, but it is preferable that they be the same. ５The fluorine-containing ester compound (3) having the same properties can be produced by using only one type of alcohol in the esterification step (B-2) described above. Also, the two R ５ Different fluorine-containing ester compounds (3) can be produced by using two or more types of alcohol in the "esterification step" described above.

[0138] According to the method for producing fluorine-containing ester compounds of this embodiment, by performing steps (A) and (B), the structural unit (R) of the diol compound (1), which is the raw material compound, is obtained. １ Regardless of the structural unit of the diol compound (1), -CF is attached to both ends of the skeleton consisting of a perfluoroether chain derived from -O. ２ CF ２ -C(=O)-OR ５ A fluorine-containing ester compound (3) having the above characteristics can be produced.

[0139] [Fluorine-containing ester compound] The fluorine-containing ester compound of this embodiment is represented by the following formula (3b). The fluorine-containing ester compound (3b) of this embodiment can be produced by the method for producing the fluorine-containing ester compound of this embodiment described above.

[0140] R ５ａ OC(=O)-CF ２ CF ２ -O-(Rf １ａ -O) ｘ -CF ２ CF ２ -C (=O) -OR ５ａ (3b) (In formula (3b), Rf １ａ x represents a divalent perfluorohydrocarbon group with 1 to 10 carbon atoms. x is an integer from 1 to 20. (Rf １ａ Rf in x structural units represented by -O) １ａ They may all be the same, or they may be different in some or all. ５ａ The R represents an alkyl group with 1 to 10 carbon atoms. ５ａ They may be the same or they may be different.

[0141] Rf in fluorine-containing ester compound (3b) １ａAs an example, Rf in the fluorine-containing ester compound (3) mentioned above. １ Examples include the following: R in fluorine-containing ester compound (3b) ５ａ As an example, R in the fluorine-containing ester compound (3) mentioned above ５ Examples can be given.

[0142] Specifically, the fluorine-containing ester compound (3b) is Rf in formula (3b). １ａ All - CF ２ CF ２ - Compounds, Rf １ａ Each independently -CF(CF ３ ) CF ２ - and -CF ２ CF (CF ３ A compound selected from the group consisting of ) - Rf １ａ All - CF ２ CF ２ CF ２ CF ２ It is preferable that the compound is -.

[0143] The fluorine-containing ester compound (3b) of this embodiment is a structural unit (Rf) of the raw material compound. １ａ A skeleton consisting of perfluoroether chains derived from -O) (-O-(Rf １ａ -O) ｘ -CF ２ CF ２ Because it contains -C(=O)-O-, it is possible to obtain perfluoropolyether compounds by combining structures with different numbers of carbon atoms, allowing for diversity in chemical structures.

[0144] [Method for producing fluorine-containing diol compounds] The method for producing fluorine-containing diol compounds according to this embodiment includes the steps of producing a fluorine-containing ester compound (3) represented by formula (3) using the method for producing a fluorine-containing ester compound (3b) according to this embodiment, and the step of reducing the ester portions at both ends of the fluorine-containing ester compound (3) (C).

[0145] The fluorine-containing ester compound (3) produced by the manufacturing method of this embodiment is a structural unit (R) of the diol compound (1) which is the raw material compound.１ A skeleton consisting of perfluoroether chains derived from -O) (-O-(Rf １ -O) ｘ -CF ２ CF ２ It can be suitably used as a raw material when producing a fluorine-containing diol compound (4) having a linking group consisting of -.

[0146] <Step (C)> Step (C) is a step in which the ester portions at both ends of the fluorine-containing ester compound (3) are reduced. This allows for the synthesis of the fluorine-containing diol compound (4) represented by the following formula (4): HO-CH ２ -CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -CH ２ -OH (4) (In formula (4), Rf １ And x is the same as in equation (3).

[0147] In step (C), known methods for reducing esters can be used as a method for reducing the ester portion of the fluorine-containing ester compound (3). For example, a method of mixing the fluorine-containing ester compound (3) with a reducing agent in a solvent can be used. The solvent used in step (C) is preferably an alcohol having 1 to 5 carbon atoms. Ethanol is preferred as the solvent because it has high solubility for the fluorine-containing diol compound (4), which is the product of step (C).

[0148] The reducing agent used in step (C) is preferably at least one selected from the group consisting of alkali metal salts of borohydride compounds such as sodium borohydride and lithium borohydride; alkaline earth metal salts of borohydride compounds such as magnesium borohydride and calcium borohydride; and aluminum hydride salts such as lithium aluminum hydride and sodium aluminum hydride. Among these, sodium borohydride is preferred as the reducing agent due to its availability and ease of handling.

[0149] According to the method for producing fluorine-containing diol compounds of this embodiment, the ester portion of the fluorine-containing ester compound (3) produced by the method of this embodiment is reduced, so the skeleton consisting of a perfluoroether chain derived from the structural unit of the diol compound (1), which is the raw material compound for the fluorine-containing ester compound (3), is reduced (-O-(Rf １ -O) ｘ -) at both ends, regardless of the structural unit of the raw material compound, -CF ２ CF ２ -CH ２ A fluorine-containing diol compound (4) having a structure in which terminal groups consisting of -OH are bonded can be produced.

[0150] [Fluorine-containing diol compound] The fluorine-containing diol compound of this embodiment is represented by the following formula (4a). The fluorine-containing diol compound (4a) of this embodiment can be produced by the method for producing the fluorine-containing diol compound of this embodiment described above.

[0151] HO-CH ２ -CF ２ CF ２ -O-(Rf １ａ -O) ｘ -CF ２ CF ２ -CH ２ -OH (4a) (In formula (4a), Rf １ａ x represents a divalent perfluorohydrocarbon group with 1 to 10 carbon atoms. x is an integer from 1 to 20. (Rf １ａ Rf in x structural units represented by -O) １ａ They may all be the same, or they may be some or all different. However, in formula (4a), Rf １ａ All - CF ２ CF ２ CF ２ (Except in the case of -)

[0152] Rf in fluorine-containing diol compound (4a) １ａ For example, Rf in fluorine-containing ester compound (3) １ (= Rf in equation (4)) １ Examples include those shown in formula (4a). The fluorine-containing diol compound (4a) is Rf １ａAll - CF ２ CF ２ - Compounds, Rf １ａ Each independently -CF(CF ３ ) CF ２ - and -CF ２ CF (CF ３ A compound selected from the group consisting of ) - Rf １ａ All - CF ２ CF ２ CF ２ CF ２ It is preferable that the compound is -. The fluorine-containing diol compound (4a) is Rf １ａ Each independently -CF(CF ３ ) CF ２ - and -CF ２ CF (CF ３ A compound selected from the group consisting of ) - Rf １ａ All - CF ２ CF ２ CF ２ CF ２ It is more preferable that the compound is -.

[0153] The fluorine-containing diol compound (4a) of this embodiment is a structural unit (Rf) of the raw material compound. １ａ A skeleton consisting of perfluoropolyether chains derived from -O) (-O-(Rf １ａ -O) ｘ -CF ２ CF ２ A hydroxymethyl group (-CH) is connected via a linking group consisting of -CH ２ It has -OH. The hydroxyl groups of the hydroxymethyl groups located at both ends of the fluorine-containing diol compound (4a) can be easily modified. Therefore, the fluorine-containing diol compound (4a) of this embodiment is useful as a raw material for the synthesis of various compounds having perfluoropolyether chains.

[0154] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the following examples.

[0155] [Example 1] (Synthesis of fluorine-containing ester compound (11C)) A fluorine-containing ester compound (11C) represented by the following formula (11C) was produced using a manufacturing method comprising the following steps (A) and (B).

[0156]

[0157] <Step (A)> The approximate chemical reaction equation for Step (A) of Example 1 is as follows:

[0158]

[0159] [Step (A-1): Michael addition step] (Synthesis of ester compound (11A)) Under a nitrogen gas atmosphere, 1.07 g of tetraethylene glycol represented by formula (31) (manufacturer: Aldrich) as the diol compound (1) was mixed with 0.03 g (0.05 eq) of potassium tert-butoxide (tBuOK) as a base and stirred to obtain a mixture.

[0160] The resulting mixture was kept at 40°C, and while stirring, 2.11 g (3.0 eq) of tert-butyl acrylate, represented by formula (32), an unsaturated compound, was added dropwise without delay to obtain the reaction solution. The temperature of the tert-butyl acrylate at the time of addition was room temperature (25°C).

[0161] After the dropwise addition of the unsaturated compound to the mixture was complete, the temperature of the reaction mixture was raised and maintained at 40°C. 15.5 hours after the dropwise addition of tert-butyl acrylate was complete (0 minutes after the start of the reaction), 0.04 g of sodium bicarbonate (baking soda) was added to the reaction mixture to quench the reaction.

[0162] After 8.5 hours and 14 hours from the start of the reaction, a portion of the reaction solution was taken to obtain test specimens. The obtained test specimens were then subjected to the methods described later. １ 1H-NMR (nuclear magnetic resonance) measurements were performed. The results showed that the Michael addition reaction between tetraethylene glycol and tert-butyl acrylate was hardly observed between 8.5 hours and 14 hours after the time elapsed.

[0163] The reaction solution was placed in an evaporator without filtration, and excess tert-butyl acrylate was removed by distillation to obtain 2.07 g of crude product as a residue. The crude product was purified by column chromatography (packing material: silica gel, developing solvent: ethyl acetate / n-hexane: 5 / 95 to 40 / 60, volume ratio) to obtain 1.58 g of the compound (yield 68%; based on tetraethylene glycol). The purified compound was identified by NMR measurement described later. As a result, the purified compound was confirmed to be the ester compound (11A) represented by formula (11A).

[0164] [Step (A-2-1): Transesterification Step] (Synthesis of the terminal ester compound (11B)) 17.78 g (39.46 mmol) of the ester compound (11A) obtained by performing Step (A-1) multiple times was added to 143.50 g of a 10% hydrogen chloride / methanol solution (hydrogen chloride-methanol reagent (5-10% by mass) manufactured by Tokyo Chemical Industry Co., Ltd.) which was kept at a temperature of 40°C and stirred, and the reaction was started.

[0165] Seven hours after the start of the reaction, a portion of the reaction solution was taken to obtain a test specimen. The obtained test specimen was then subjected to the method described later. １ 1H-NMR measurements were performed. The results confirmed that the peak originating from the tert-butyl ester located at the terminal end of the ester compound (11A) was replaced by a peak originating from the methyl ester.

[0166] Therefore, 33.39 g of sodium bicarbonate (baking soda) was added to the reaction mixture to quench the reaction. Then, 150 ml of acetone was added to the reaction mixture and suspended. The suspension was filtered to remove the precipitate. When the filtrate was concentrated using an evaporator, a precipitate formed, so acetone was added to the filtrate again and filtered to remove the precipitate. The filtrate was then concentrated using an evaporator to obtain 13.3 g of crude product.

[0167] The crude product was purified by column chromatography (packing material: silica gel, developing solvent: ethyl acetate / n-hexane: 10 / 90 to 100 / 0, volume ratio), and 9.02 g of the compound was obtained (yield 62%; based on ester compound (11A)). The purified compound was identified by NMR measurement described later. As a result, the purified compound was confirmed to be the double-terminated ester compound (11B) represented by formula (11B).

[0168] <Step (B)> The approximate chemical reaction equation for Step (B) of Example 1 is as follows:

[0169]

[0170] "First Fluorination Step (B-1-1)" 11 g of the terminal ester compound (11B) produced by repeating step (A) of Example 1 multiple times was taken and dissolved in 57 mL of the solvent tetrachlorohexafluorobutane (hereinafter sometimes referred to as "HFTCB") to obtain the raw material solution.

[0171] 3100 mL of HFTCB was introduced into a 5 L autoclave and sealed. Next, nitrogen gas was introduced into the autoclave until the internal pressure reached 0.3 MPaG (gauge pressure), and this process was slowly released to atmospheric pressure 10 times to purge the autoclave. Subsequently, fluorine gas was circulated into the autoclave at a flow rate of 588 mL / min and nitrogen gas at 4600 mL / min, and while cooling the autoclave to a temperature of 25°C, the above raw material solution was supplied into the autoclave at a flow rate of 1.52 g / min based on the solution. The pressure inside the autoclave when introducing the fluorine gas was 0.102 MPa. The total equivalent amount of fluorine gas introduced into the autoclave was 2.1 equivalents relative to the total number of moles of hydrogen atoms contained in the terminal ester compound (11B).

[0172] "Second fluorination step (B-1-2)" Hexafluorobenzene (C), a perhalogen unsaturated hydrocarbon compound. ６ F ６1.87 g of fluorine gas was dissolved in 73 mL of HFTCB to obtain a perhalogen solution. After the first fluorination step (B-1-1) was completed, fluorine gas was circulated into the autoclave at a flow rate of 150 mL / min and nitrogen gas at a flow rate of 1350 mL / min. While adjusting the temperature inside the autoclave to 25°C to 30°C, the perhalogen solution was supplied into the autoclave at a flow rate of 0.83 g / min based on the solution. The pressure inside the autoclave was maintained at 0.101 MPa.

[0173] The flow rate of hexafluorobenzene was calculated in terms of the number of moles of unsaturated bonds in hexafluorobenzene and was set to 0.1 molar times the flow rate of fluorine gas. After the supply of the perhalogen solution was completed, the flow of fluorine gas and nitrogen gas was continued for 10 minutes. Then, the flow of fluorine gas was stopped, and nitrogen gas alone was flowed at a flow rate of 1350 mL / min for 1 hour to purge the autoclave. By performing the above steps, the intermediate compound fluorine compound (33) represented by formula (33) was produced.

[0174] "Esterification Process (B-2)" After the second fluorination process (B-1-2), nitrogen gas flow was continued and the temperature inside the autoclave was adjusted to 25°C to 27°C. Then, 12 g of methanol was introduced into the autoclave, and the fluorine compound (33) and methanol were reacted at atmospheric pressure (0.1 MPa) in HFTCB, the solvent used in the solutions used in the first fluorination process (B-1-1) and the second fluorination process (B-1-2), for 3 minutes.

[0175] The reaction mixture recovered from the autoclave was washed with sodium carbonate solution to separate the two layers, and the solvent layer was recovered. The recovered solvent layer was dried using sodium sulfate and sodium fluoride, and the solid was filtered off. The solvent was removed from the filtrate using an evaporator to obtain 23 g of product (95% recovery). The obtained product was identified by NMR measurement described later. As a result, it was confirmed that the obtained product was a fluorine-containing ester compound (11C) represented by formula (11C).

[0176] (Synthesis of fluorine-containing diol compound (11)) Next, using the fluorine-containing ester compound (11C) obtained by step (B), a fluorine-containing diol compound (11) represented by the following formula (11) was produced using a manufacturing method including the following step (C).

[0177]

[0178] <Step (C)> The approximate chemical reaction equation for Step (C) of Example 1 is as follows:

[0179]

[0180] (Reduction of fluorine-containing ester compounds (11C)) 84.1 g of ethanol, the solvent, is placed in a round-bottom flask and cooled with ice, and sodium borohydride (NaBH) is added as a reducing agent. ４ 1.42 g was added, and the temperature inside the round-bottom flask was measured. The result was 0.8°C.

[0181] While the round-bottom flask was kept ice-cooled, 22.8 g of the fluorine-containing ester compound (11C) obtained in step (B) was added dropwise to the flask over 30 minutes, and then washed with 9.44 g of ethanol. After that, the ice bath for the round-bottom flask was terminated, and the reaction was allowed to proceed for 5 hours while the temperature of the reaction solution returned to room temperature.

[0182] The reaction products were subjected to NMR measurements, as described later. The results confirmed that the reduction reaction of the ester portion of the fluorine-containing ester compound (11C) had been completed.

[0183] After the reaction was complete, 10 mL of 4 mol / L hydrochloric acid was added dropwise to the reaction solution to confirm that the pH of the reaction solution was 3. Then, an aqueous solution of sodium bicarbonate (5.4 g of sodium bicarbonate, 60 mL of water) was added to confirm that the pH of the reaction solution was 7. Subsequently, the ethanol was removed using an evaporator, and the aqueous layer was extracted in three separate stages using 50 mL of a fluorinated solvent (product name: Asahi Clean® AE3000, manufacturer: AGC Inc.). After drying the extract over magnesium sulfate, the solid was filtered off. The solvent was removed from the filtrate using an evaporator to obtain 19.37 g of crude product (91.6% recovery of the theoretical amount).

[0184] The obtained compound was identified by NMR measurement, as described later. As a result, it was confirmed that it was a fluorine-containing diol compound (11) obtained by reducing the ester portion of the fluorine-containing ester compound (11C).

[0185] The obtained crude product was fractionated using a preparative chromatography apparatus (product name: SmartFlash series, manufactured by Yamazen Corporation). For fractionation, 200 g of silica was used as the packing material for the preparative column, and ethyl acetate / n-hexane = 15 / 85 to 20 / 80 (volume ratio) was used as the mobile phase.

[0186] Each fraction was subjected to gas chromatography measurement under the measurement conditions shown below. As a result, the high-purity fractions of the target diol compound of formula (11) were mixed, and the solvent of the mobile phase was removed by distillation to obtain 11.9 g of the target fluorine-containing diol compound (11) (yield based on compound (11C): 61.9%).

[0187] [Gas Chromatography (GC) Measurement Conditions] GC instrument: Agilent 6850 series, manufactured by Agilent Technologies Column: Agilent J&W DB17 Oven temperature: 70°C (2 min) → 10°C / min → 250°C (20 min) Injection port: Split (split ratio 20:1), 250°C Detector: FID, 250°C Injection mode: Constant Flow (column flow rate 1.6 mL / min (He)) Injection volume: 1 μL Target peak: 6.3 min

[0188] [Example 2] (Synthesis of fluorine-containing ester compound (12C)) A fluorine-containing ester compound (12C) represented by the following formula (12C) was produced using a manufacturing method comprising the following steps (A) and (B).

[0189] CH ３ OC(=O)-CF ２ CF ２ O-(C) ３ F ６ -O) ３ -CF ２ CF ２ -C(=O)-OCH ３(12C) (In formula (12C), (C ３ F ６ -O) ３ The structural unit represented by (CF ２ CF (-CF ３ )O) and (CF(-CF ３ ) CF ２ It is a mixture of isomers consisting of O) and ).

[0190] <Process (A)> [Process (A-1): Michael addition process] (Synthesis of ester compound (12A)) Under a nitrogen gas atmosphere, 43.21 g of tripropylene glycol (manufacturer: Tokyo Chemical Industry Co., Ltd.) as the diol compound (1) was mixed with 0.90 g (0.1 eq) of sodium hydride (60%, oil dispersion) as a base and stirred to obtain a mixture.

[0191] The aforementioned tripropylene glycol (HO-(C) ３ H ６ -O) ３ -H) is (C ３ H ６ -O) ３ The structural unit represented by (CH ２ CH(-CH ３ )O) and (CH(-CH ３ )CH ２ A mixture of isomers consisting of O) was used.

[0192] While stirring the resulting mixture, 57.6 g (2.1 eq) of tert-butyl acrylate, an unsaturated compound, was added dropwise over 2 hours to obtain the reaction solution. The ice bath in the container was maintained for 4 hours from the time the addition of tert-butyl acrylate to the mixture was completed (0 minutes into the reaction) to keep the temperature of the reaction solution within the range of 2°C to 8°C. After that, the ice bath in the container was terminated, and the temperature of the reaction solution was raised to room temperature (25°C).

[0193] At 26.5 hours after the start of the reaction, a 5% citric acid solution was added to the reaction mixture to quench the reaction. The mixture and reaction mixture were continuously stirred from before the dropwise addition of tert-butyl acrylate to the mixture until the reaction of the reaction mixture was stopped. The reaction mixture was transferred to a separatory funnel and extracted with methylene chloride, and the organic layer was dried with sodium sulfate. Sodium sulfate was then removed by filtration, and the filtrate was concentrated to obtain 88.3 g of crude product.

[0194] The crude products obtained by repeating the same procedure were mixed (total 109.5 g) and purified by column chromatography (packing material: silica gel, developing solvent: ethyl acetate / n-hexane, 10 / 90 to 40 / 60, volume ratio) to obtain 74.7 g of the compound. The purified compound was identified by NMR measurement described later. As a result, the purified compound was confirmed to be the ester compound (12A) represented by the following formula (12A).

[0195] tBu-OC(=O)-CH ２ CH ２ -O-(C ３ H ６ -O) ３ -CH ２ CH ２ -C(=O)-O-tBu (12A) (In formula (12A), (C ３ H ６ -O) ３ The structural unit represented by (CH ２ CH(-CH ３ )O) and (CH(-CH ３ )CH ２ It is a mixture of isomers consisting of O) and ).

[0196] [Step (A-2-1): Transesterification Step] (Synthesis of the terminal ester compound (12B)) 27.41 g (61.11 mmol) of the ester compound (12A) obtained by step (A-1) was dissolved in 159.58 g (5 mol) of methanol. 8.3 mL (equivalent to 2.5 eq) of concentrated sulfuric acid was added dropwise to the resulting solution at room temperature (25°C), and the mixture was stirred to initiate the reaction.

[0197] After 190.5 hours from the start of the reaction, a portion of the reaction solution was taken to obtain a test specimen. The obtained test specimen was then subjected to the method described later. １ 1H-NMR measurements were performed. The results confirmed that the peak originating from the tert-butyl ester located at the terminal end of the ester compound (12A) was replaced by a peak originating from the methyl ester.

[0198] Therefore, 191.5 hours after the start of the reaction, 46.24 g of trisodium citrate was added to the reaction mixture to quench the reaction. The reaction mixture was then transferred to a separatory funnel and extracted using methylene chloride and water. Magnesium sulfate was added to the organic layer as a drying agent and dried. The drying agent was removed from the dried organic layer by filtration, and the filtrate was removed using an evaporator to obtain 25.72 g of crude product.

[0199] The crude product was purified by column chromatography (packing material: silica gel, developing solvent: ethyl acetate / n-hexane, 10 / 90 to 70 / 30, volume gradient) to obtain 22.49 g of the compound (100% yield). The purified compound was identified by NMR measurement described later. As a result, the purified compound was confirmed to be the terminal ester compound (12B) represented by the following formula (12B).

[0200] CH ３ -OC(=O)-CH ２ CH ２ -O-(C ３ H ６ -O) ３ -CH ２ CH ２ -C(=O)-O-CH ３ (12B) (In formula (12B), (C ３ H ６ -O) ３ The structural unit represented by (CH ２ CH(-CH ３ )O) and (CH(-CH ３ )CH ２ It is a mixture of isomers consisting of O) and ).

[0201] <Step (B)> "First Fluorination Step (B-1-1)" 49 g of the terminal ester compound (12B) obtained by carrying out Step (A) of Example 2 was taken and dissolved in 254 mL of tetrachlorohexafluorobutane (hereinafter sometimes referred to as "HFTCB"), which is a solvent, to obtain a raw material solution. Except for using the raw material solution obtained in this way, the first fluorination step (B-1-1) and the second fluorination step (B-1-2) of Example 2 were carried out in the same manner as in Example 1 to produce a fluorine compound, which is an intermediate compound.

[0202] "Esterification Process (B-2)" After the second fluorination process (B-1-2), nitrogen gas flow was continued and the temperature inside the autoclave was adjusted to 25°C to 27°C. 75 g of methanol was introduced into the autoclave, and the fluorine compound and methanol were reacted at atmospheric pressure (0.1 MPa) for 14 minutes in HFTCB, the solvent used in the solutions for the first fluorination process (B-1-1) and the second fluorination process (B-1-2).

[0203] The reaction solution recovered from the autoclave was washed with sodium carbonate solution to separate the two layers, and the solvent layer was recovered. The recovered solvent layer was dried with sodium sulfate, and the solid was filtered off. The solvent was removed from the filtrate using an evaporator to obtain 72 g of product (recovery rate 78%). The obtained product was identified by NMR measurement as described later. As a result, it was confirmed that the obtained product was a fluorine-containing ester compound (12C) represented by the following formula (12C).

[0204] CH ３ OC(=O)-CF ２ CF ２ O-(C) ３ F ６ -O)3-CF ２ CF ２ -C(=O)-OCH ３ (12C) (In formula (12C), (C ３ F ６ -O) ３ The structural unit represented by (CF ２ CF (-CF ３ )O) and (CF(-CF ３ ) CF２ It is a mixture of isomers consisting of O) and ).

[0205] <Distillation Purification> The fluorine-containing ester compound (12C) obtained by the esterification process (B-2) was purified by simple distillation under the following conditions, yielding 43.1 g. After cutting the initial distillate, the main distillate was distilled at a vapor temperature of 71°C to 91°C and a pressure of 0.13 torr to 0.16 torr.

[0206] (Synthesis of fluorine-containing diol compound (12)) Next, using the fluorine-containing ester compound (12C) obtained by step (B), a fluorine-containing diol compound (12) represented by the following formula (12) was produced using a manufacturing method including the following step (C).

[0207] HO-CH ２ -CF ２ CF ２ -O-(C ３ F ６ -O) ３ -CF ２ CF ２ -CH ２ -OH (12) (In formula (12), (C ３ F ６ -O) ３ The structural unit represented by (CF ２ CF (-CF ３ )O) and (CF(-CF ３ ) CF ２ It is a mixture of isomers consisting of O) and ).

[0208] <Step (C)> (Reduction of fluorine-containing ester compound (11C)) 150 g of ethanol, which is the solvent, is placed in a round-bottom flask and cooled with ice, and sodium borohydride (NaBH), which is the reducing agent, is added. ４ 2.63 g was added, and the temperature inside the round-bottom flask was measured. The result was 4°C.

[0209] While the round-bottom flask was kept ice-cooled, 43.1 g of a fluorine-containing ester compound (12C), purified by distillation, was added dropwise to the flask over 1 hour, and then washed with 17.3 g of ethanol. After that, the ice bath for the round-bottom flask was removed, and the reaction was allowed to proceed for 2 hours while the temperature of the reaction mixture returned to room temperature.

[0210] The reaction products were subjected to NMR measurements, as described later. The results confirmed that the reduction reaction of the ester portion of the fluorine-containing ester compound (12C) had been completed.

[0211] After the reaction was complete, 18 mL of 4 mol / L hydrochloric acid was added dropwise to the reaction solution to confirm that the pH of the reaction solution was 3. Then, an aqueous solution of sodium bicarbonate (10.7 g of sodium bicarbonate, 120 mL of water) was added to confirm that the pH of the reaction solution was 7. Subsequently, the ethanol was removed using an evaporator, and the aqueous layer was extracted in three separate stages using 120 mL of a fluorinated solvent (product name: Asahi Clean® AE3000, manufacturer: AGC Inc.). After drying the extract over magnesium sulfate, the solid was filtered off. The solvent was removed from the filtrate using an evaporator to obtain 42.3 g of crude product (recovery rate 106%). The recovery rate exceeding 100% is due to the effect of residual solvent.

[0212] The obtained compound was identified by NMR measurement described later. As a result, it was confirmed to be the fluorine-containing diol compound (12) represented by formula (12) above.

[0213] The obtained crude product was fractionated using a preparative chromatography apparatus in the same manner as the crude product obtained in step (C) of Example 1, except that 500 g of silica was used as the packing material for the preparative column, and gas chromatography analysis was performed. This yielded 36.0 g of the target fluorine-containing diol compound (12) (yield based on compound (12C): 89.6%).

[0214] [Example 3] <Process (A)> [Process (A-1): Michael addition process] The approximate chemical reaction equation for process (A-1) of Example 3 is as follows.

[0215]

[0216] (Synthesis of ester compound (13A)) Under a nitrogen gas atmosphere, 1.00 g of 1,3-propanediol trimer (manufactured by Wuxi) represented by formula (34) as diol compound (1) was added to 0.03 g (0.05 eq) of potassium tert butoxide (tBuOK) as a base, and the mixture was stirred under heating conditions to 70°C to obtain a mixture. The obtained mixture was cooled to room temperature (approximately 25°C), and while maintaining the same temperature, it was stirred, and 1.40 g (1.59 mL, 2.1 eq) of tert butyl acrylate represented by formula (32), an unsaturated compound, was added all at once to obtain a reaction solution.

[0217] Samples of the reaction solution were collected one hour and two hours after the start of the reaction to obtain test specimens. The obtained test specimens were then subjected to the methods described later. １ 1H-NMR (nuclear magnetic resonance) measurements were performed. The results confirmed that the Michael addition reaction between the 1,3-propanediol trimer and tert-butyl acrylate had not proceeded sufficiently. Therefore, the temperature of the reaction solution was raised to 40°C two hours after the start of the reaction.

[0218] Four hours after the start of the reaction, a portion of the reaction solution is taken and processed using the method described below. １ ¹H-NMR measurements were performed. As a result, it was confirmed that the Michael addition reaction had not proceeded sufficiently, similar to the above. Therefore, four hours after the start of the reaction, 0.09 g (0.15 eq) of potassium tert butoxide and 0.68 mL (0.9 eq) of tert butyl acrylate were added to the reaction solution, and the temperature of the reaction solution was raised to 50°C.

[0219] Six hours after the start of the reaction, a portion of the reaction solution is taken and processed using the method described below. １ ¹H-NMR (nuclear magnetic resonance) measurements were performed. The results confirmed that the Michael addition reaction between the 1,3-propanediol trimer and tert-butyl acrylate was completed. Therefore, the reaction was quenched by adding a 5% citric acid solution to the reaction mixture.

[0220] The reaction solution after the reaction was purified by column chromatography in the same manner as the crude product in step (A-1) of Example 1, and 1.05 g of the compound was obtained (yield 45%). The purified compound was identified by NMR measurement as described later. As a result, it was confirmed that the purified compound was the ester compound (13A) represented by formula (13A).

[0221] Table 1 shows the raw materials and quantities used in each of the following steps: (A), (B), and (C) in Examples 1 to 3.

[0222]

[0223] <NMR Measurement> The products generated in each step of Examples 1 to 3 were identified by NMR (nuclear magnetic resonance) measurement. A Bruker BioSpin AVANCE III 400 NMR spectrometer was used. For NMR measurement, the samples were diluted in d-chloroform and d-acetone solvents before use. １ The standard for H-NMR chemical shift is to set the peak of tetramethylsilane to 0.0 ppm. １９ The baseline for the F-NMR chemical shift was set to a peak of -164.9 ppm for hexafluorobenzene.

[0224] The ester compounds (11A), terminal ester compounds (11B), fluorine-containing ester compounds (11C), fluorine-containing diol compounds (11), ester compounds (12A), terminal ester compounds (12B), fluorine-containing ester compounds (12C), fluorine-containing diol compounds (12), and ester compounds (13A) produced in Examples 1 to 3 were identified based on the NMR measurement results shown below.

[0225] (Ester compound (11A)) tBu-O-C(=O)-CH ２ CH ２ -O-(CH ２ CH ２ -O) ４ -CH ２ CH ２ -C(=O)-O-tBu １ H-NMR (CDCl ３): δ [ppm] = 1.45 ppm (18H), 2.48 to 2.52 ppm (4H), 3.5 to 3.8 ppm (20H)

[0226] (Double-terminal ester compound (11B)) CH ３ -O-C(=O)-CH ２ CH ２ -O-(CH ２ CH ２ -O) ４ -CH ２ CH ２ -C(=O)-O-CH ３ １ H-NMR (CDCl ３ ): δ [ppm] = 2.58 to 2.63 ppm (4H), 3.5 to 3.9 ppm (26H)

[0227] (Fluorine-containing ester compound (11C)) CH ３ -O-C(=O)-CF ２ CF ２ -O-(CF ２ CF ２ -O) ４ -CF ２ CF ２ -C(=O)-O-CH ３ １ H-NMR (acetone-D ６ ): δ [ppm] = 4.11 ppm (6H) １９ F-NMR (acetone-D ６ ): δ [ppm] = -122.7 ppm (4F), -89.7 ppm (16F), -86.7 ppm (4F)

[0228] (Fluorine-containing diol compound (11)) HO-CH ２ -CF ２ CF ２ -O-(CF ２ CF ２ -O) ４ -CF ２ CF ２ -CH ２ -OH １ H-NMR (acetone-D ６ ): δ [ppm] = 4.05 to 4.15 ppm (4H), 5.15 to 5.19 ppm (2H) １９ F-NMR (acetone-D６ ): δ [ppm] = -126.5 ppm (4F), -89.7 ppm (16F), -86.7 ppm (4F)

[0229] (Ester compound (12A)) tBu-O-C(=O)-CH ２ CH ２ -O-(C ３ H ６ -O) ３ -CH ２ CH ２ -C(=O)-O-tBu １ H-NMR (CDCl ３ ): δ [ppm] = 1.11-1.15 ppm (9H), 1.46 ppm (18H), 2.45-2.49 ppm (4H), 3.28-3.58 ppm (13H)

[0230] (Double-terminal ester compound (12B)) CH ３ -O-C(=O)-CH ２ CH ２ -O-(C ３ H ６ -O) ３ -CH ２ CH ２ -C(=O)-O-CH ３ １ H-NMR (CDCl ３ ): δ [ppm] = 1.10-1.15 ppm (9H), 2.55-2.60 ppm (4H), 3.30-3.82 ppm (19H)

[0231] (Fluorine-containing ester compound (12C)) CH ３ -O-C(=O)-CF ２ CF ２ -O-(C ３ F ６ -O) ３ -CF ２ CF ２ -C(=O)-O-CH ３ １ H-NMR (acetone-D ６ ): δ [ppm] = 4.06 ppm (6H) １９ F-NMR (acetone-D ６): δ [ppm] = -147.0 to -145.3ppm, -142.3 to -141.1ppm, -123.5 to -121.5ppm, -87.2 to -86.2ppm, -85.1 to -82.9ppm, -82.9 to -79.9ppm

[0232] (Fluorine-containing diol compound (12)) HO-CH ２ -CF ２ CF ２ -O-(C ３ F ６ -O) ３ -CF ２ CF ２ -CH ２ -OH １ H-NMR (acetone-D ６ ): δ [ppm] = 4.05 to 4.13 ppm (4H), 5.14 ppm (2H) １９ F-NMR (acetone-D ６ ): δ [ppm] = -147.5 to -145.3ppm, -142.5 to -140.5ppm, -127.3 to -125.7ppm, -87.2 to -86.0ppm, -85.0 to -83.1ppm, -82.8 to -79.8ppm

[0233] (Ester compound (13A)) tBu-O-C(=O)-CH ２ CH ２ -O-(CH ２ CH ２ CH ２ -O) ３ -CH ２ CH ２ -C(=O)-O-tBu １ H-NMR (CDCl ３ ): δ [ppm] = 1.43-1.44ppm (18H), 1.73-1.77ppm (6H), 2.40-2.44ppm (4H), 3.42-3.49ppm (12H), 3.60-3.63ppm (4H)

[0234] According to the present invention, at both ends of a skeleton consisting of a perfluoroether chain derived from the structural unit of the raw material compound, regardless of the structural unit of the raw material compound, -CF ２ CF ２To provide a method for producing a fluorine-containing ester compound that can be suitably used as a raw material for a fluorine-containing diol compound having a structure in which - is bonded, and that at both ends of a skeleton consisting of a perfluoroether chain derived from the structural unit of the raw material compound, -CF regardless of the structural unit of the raw material compound. ２ CF ２ To provide a method for producing a fluorine-containing diol compound having a structure in which - is bonded, and to provide a skeleton consisting of a perfluoroether chain derived from the structural unit of the raw material compound, with -CF not derived from the structural unit of the raw material compound at both ends. ２ CF ２ This makes it possible to provide fluorine-containing diol compounds having a structure in which a negative charge is bonded.

Claims

1. A method for producing a fluorine-containing ester compound, characterized in that it comprises at least a step (A) and the following step (B), wherein said step (A) is a step comprising the following step (A-1) and the following step (A-2) (provided that step (A-2) may be omitted when R in the following formula (2) ２ is not a cyano group). [Step (A-1)] Step (A-1) is a step of subjecting a diol compound (1) represented by the following formula (1) to a Michael addition reaction with at least one unsaturated compound selected from alkyl acrylates which are ester compounds of an alkyl alcohol having 1 to 10 carbon atoms and acrylic acid, and acrylonitrile in the presence of a base to obtain a compound (2) represented by the following formula (2): HO-(R １ -O) ｘ -H (1) (In formula (1), R １ represents a divalent hydrocarbon group having 1 to 10 carbon atoms, wherein some or all hydrogen atoms may be substituted with fluorine atoms; x is an integer of 1 to 20; R in x structural units represented by (R １ -O) １ may all be the same, or some or all may be different.) R ２ -CH ２ CH ２ -O-(R １ -O) ｘ -CH ２ CH ２ -R ２ (2) (In formula (2), R １ and x are the same as those in formula (1); R ２ is -(C=O)-OR ３ (R ３ represents an alkyl group having 1 to 10 carbon atoms) or a cyano group; two R ２ may be the same or different.) [Step (A-2)] Step (A-2) is a step of converting said compound (2) into a double-terminal ester compound (2a) represented by the following formula (2a); when R in formula (2) is not a cyano group and step (A-2) is not omitted, R ２ is not a cyano group and step (A-2) is not omitted, R ３ and R ４ are different alkyl groups. R ４ OC(=O)-CH ２ CH ２ -O-(R １ -O) ｘ -CH ２ CH ２ -C (=O) -OR ４ (2a) (In formula (2a), R １ And x are the same as in equation (1). R ４ The R represents an alkyl group with 1 to 10 carbon atoms. ４ (These may be the same or different.) [Step (B)] Step (B) involves fluorinating the two terminal ester compounds (2a) to obtain an intermediate compound (3a) represented by the following formula (3a), and then F-C(=O)-CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -C(=O)-F (3a) (In formula (3a), Rf １ R in equation (1) １ This represents a divalent perfluorohydrocarbon group in which a hydrogen atom is replaced by a fluorine atom. x is the same as in formula (1). ) The intermediate compound (3a) is then R ５ -OH(R) ５ R represents an alkyl group having 1 to 10 carbon atoms. This is a step to obtain a fluorine-containing ester compound (3) represented by the following formula (3) by reacting it with an alkyl alcohol represented by ( ). ５ OC(=O)-CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -C (=O) -OR ５ (3) (In formula (3), Rf １ R in equation (1) １ R represents a divalent perfluorocarbon group in which a hydrogen atom is replaced by a fluorine atom. ５ The R represents an alkyl group with 1 to 10 carbon atoms. ５ x may be the same or different. x is the same as in equation (1).

2. The method for producing a fluorine-containing ester compound according to claim 1, wherein the unsaturated compound is the alkyl acrylate.

3. The unsaturated compound is the alkyl acrylate, and the R in compound (2) ２ is -C(=O)-OR ３ (R ３ The method for producing a fluorine-containing ester compound according to claim 1, wherein step (A-2) is a transesterification step (A-2-1) in which the compound (2) is transesterified to obtain the terminal ester compound (2a).

4. The method for producing a fluorine-containing ester compound according to claim 1, wherein the unsaturated compound is acrylonitrile.

5. The unsaturated compound is acrylonitrile, and R in compound (2) ２ The method for producing a fluorine-containing ester compound according to claim 1, wherein is -CN, and step (A-2) is an alcohol decomposition step (A-2-2) in which the cyano group of compound (2) is decomposed by alcohol decomposition to obtain the two-terminal ester compound (2a).

6. The x R groups in the above formula (1) １ are each independently selected from the group consisting of -CH ２ -, -CH ２ CH ２ -, -CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -, -CH ２ CH(CH ３ )-, -CH ２ CH ２ CH ２ CH ２ -, -CF ２ -, -CF ２ CF ２ -, -CF ２ CF ２ CF ２ -, -CF(CF ３ )CF ２ -, -CF ２ CF(CF ３ )-, -CF ２ CF ２ CF ２ CF ２ -, -CF ２ CH ２ -, -CH ２ CF ２ -, -CF ２ CF ２ CH ２ -, -CH ２ CF ２ CF ２ -, -CF ２ CF ２ CF ２ CH ２ -, and -CH ２ CF ２ CF ２ CF ２ -, wherein the left bond of the group binds to the oxygen atom to which the structural unit represented by (R １ -O) binds, and the right bond binds to the oxygen atom in (R １ -O), the method for producing a fluorine-containing ester compound according to claim 1.

7. x Rs in equation (1) above １ All are identical, -CH ２ CH ２ -ien-CH ２ CH ２ CH ２ -, -CH(CH ３ )CH ２ -ien-CH ２ CH (CH ３ ) -, -CH ２ CH ２ CH ２ CH ２ - (The left-hand joint is (R １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (R １ A method for producing a fluorine-containing ester compound according to claim 1, wherein the compound is one selected from the group consisting of (bonding to an oxygen atom in -O).

8. x Rs in equation (1) above １ Each of them independently, -CH(CH ３ )CH ２ - and -CH ２ CH (CH ３ ) - (The left-hand joint is (R １ The structural unit represented by -O) is bonded to the oxygen atom to which it is bonded, and the bond on the right side is (R １ A method for producing a fluorine-containing ester compound according to claim 1, selected from the group consisting of (bonding to an oxygen atom in -O).

9. The method for producing a fluorine-containing ester compound according to claim 1, wherein in step (A-1), the molar ratio of the unsaturated compound to the diol compound (1) (unsaturated compound) / (diol compound) is 2.0 to 5.

0.

10. The method for producing a fluorine-containing ester compound according to claim 1, wherein the base in step (A-1) is at least one selected from the group consisting of potassium tert butoxide, sodium hydride, and potassium hydroxide.

11. A method for producing a fluorine-containing diol compound represented by the following formula (4), comprising the steps of: producing a fluorine-containing ester compound (3) represented by formula (3) using the method for producing a fluorine-containing ester compound described in any one of claims 1 to 10; and reducing the ester portion of the fluorine-containing ester compound (3) (C). HO-CH ２ -CF ２ CF ２ -O-(Rf １ -O) ｘ -CF ２ CF ２ -CH ２ -OH (4) (In formula (4), Rf １ And x are the same as in equation (3).

12. A fluorine-containing diol compound represented by the following formula (4a): HO-CH ２ -CF ２ CF ２ -O-(Rf １ａ -O) ｘ -CF ２ CF ２ -CH ２ -OH (4a) (In formula (4a), Rf １ａ x represents a divalent perfluorohydrocarbon group with 1 to 10 carbon atoms. x is an integer from 1 to 20. (Rf １ａ Rf in x structural units represented by -O) １ａ They may all be the same, or they may be some or all different. However, in formula (4a), Rf １ａ All - CF ２ CF ２ CF ２ (Except in the case of -) 13. Rf in formula (4a) １ａ All - CF ２ CF ２ - The fluorine-containing diol compound according to claim 12.

14. Rf in formula (4a) １ａ Each of them independently, -CF(CF ３ ) CF ２ - and -CF ２ CF (CF ３ ) - (The left-hand joint is (Rf １ａ The structural unit represented by -O) is bonded to the oxygen atom it is bonded to, and the bond on the right side is (Rf １ａ A fluorine-containing diol compound according to claim 12, selected from the group consisting of (bonding to an oxygen atom in -O).

15. Rf in formula (4a) １ａ All - CF ２ CF ２ CF ２ CF ２ - The fluorine-containing diol compound according to claim 12.

Images