JP2024074702A - Solvent and method for producing fluorine-containing compound - Google Patents

Abstract

To provide a solvent that offers excellent solubility of a raw material compound and enables improved yield of a target compound, and a method for producing a fluorine-containing compound using the solvent.SOLUTION: A solvent is used to fluorinate an organic compound with at least one atom or bond capable of undergoing fluorination, the solvent containing a halogenated organic compound. The halogenated organic compound has divalent halogenated hydrocarbon groups and oxygen atoms. The ratio of the number of the oxygen atoms to the number of carbon atoms in the halogenated hydrocarbon groups is 0.65 or more.SELECTED DRAWING: None

Description

This disclosure relates to a method for producing a solvent and a fluorine-containing compound.

Many fluorine-containing compounds are industrially useful as solvents, etc., and various manufacturing methods have been developed. One method known for fluorinating a compound having at least one fluorinatable atom or bond (hereinafter also referred to as "raw material compound") is to carry out a fluorination reaction in the liquid phase using fluorine gas.

Solvents used in liquid phase fluorination (also referred to as "fluorinated solvents") include chlorofluorocarbons (hereinafter also referred to as "CFCs") such as CCl ₂ FCClF ₂ , and perfluoropolyethers (hereinafter also referred to as "PFPEs") (see Patent Document 1).

WO 00/56694

CFCs are chemically very stable, and therefore have a long lifespan in the troposphere after vaporization, and can diffuse up to the stratosphere. Therefore, when CFCs reach the stratosphere, they are decomposed by ultraviolet rays, generating chlorine radicals that destroy the ozone layer.
According to the present inventors, among the various PFPEs described as fluorinated solvents in Patent Document 1, there are compounds in which there is room for improvement in the solubility of raw material compounds.
In view of the above circumstances, an object of the present disclosure is to provide a solvent which has a small environmental impact, is excellent in solubility of raw material compounds, and can improve the yield of a target compound, and a method for producing a fluorine-containing compound using the solvent.

The present disclosure includes the following aspects.
<1> A solvent used for fluorinating an organic compound having at least one fluorinatable atom or bond, the solvent comprising a halogenated organic compound,
the halogenated organic compound has a divalent halogenated hydrocarbon group and an oxygen atom,
A solvent in which the ratio of the number of oxygen atoms to the number of carbon atoms in the halogenated hydrocarbon group is 0.65 or more.
<2> The halogenated organic compound has a unit structure represented by the following formula (1) and formula (2),
The solvent according to the above item <1>, wherein a ratio of the number of unit structures represented by formula (2) to the number of unit structures represented by formula (1) is 0.7 or more.

In formula (1),
R ^X represents a divalent halogenated hydrocarbon group having 2 or more carbon atoms;
In formula (2),
Each X independently represents a halogen atom.
<3> The solvent according to <1> or <2> above, wherein the halogenated hydrocarbon group is a linear hydrocarbon group.
<4> The solvent according to <1> or <2> above, wherein the halogenated organic compound is represented by the following formula (3):

In formula (3),
A ¹ and A ² each independently represent a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom;
Each X independently represents a halogen atom.
m and n each independently represent an integer of 1 to 200;
n/m is 0.7 or more.
<5> The solvent according to <1> or <2> above, wherein the halogenated organic compound is a perfluoro compound.
<6> The solvent according to <1> or <2> above, wherein the halogenated organic compound is a perfluoroether compound.
<7> The solvent according to <1> or <2> above, wherein the halogenated organic compound has a number average molecular weight of 1,000 to 100,000.
<8> The solvent according to <1> or <2> above, wherein the organic compound having at least one fluorinable atom or bond is an ester compound.
<9> A method for producing a fluorine-containing compound, comprising: a step of fluorinating an organic compound having at least one fluorinatable atom or bond in the solvent according to any one of <1> to <8> above into which fluorine gas has been introduced.

The present disclosure provides a solvent that has a small environmental impact, excellent solubility for raw material compounds, and can improve the yield of target compounds, as well as a method for producing a fluorine-containing compound using the solvent.

Below, the form for implementing the embodiment of the present disclosure will be described in detail. However, the embodiment of the present disclosure is not limited to the following embodiment. In the following embodiment, the components (including element steps, etc.) are not essential unless specifically stated. The same applies to the numerical values and their ranges, and they do not limit the embodiment of the present disclosure.

In the present disclosure, the term "step" includes not only a step that is independent of other steps, but also a step that cannot be clearly distinguished from other steps as long as the purpose of the step is achieved.
In the present disclosure, the numerical range indicated using "to" includes the numerical values before and after "to" as the minimum and maximum values, respectively.
In the present disclosure, each component may contain multiple types of the corresponding substance. When multiple substances corresponding to each component are present in the composition, the content of each component means the total content of the multiple substances present in the composition, unless otherwise specified.
In this disclosure, "organic group" refers to a group that contains essentially a carbon atom.
In the present disclosure, the "hydrocarbon group" may be any of a linear, branched, or cyclic group, and may be any of a saturated aliphatic hydrocarbon group, an unsaturated aliphatic hydrocarbon group, and an aromatic hydrocarbon group.
In this disclosure, "partially halogenated" means that only a portion of the halogenatable sites on a compound are halogenated.

[solvent]
The solvent of the present disclosure (hereinafter also referred to as "the solvent") is used for fluorinating an organic compound having at least one fluorinatable atom or bond, and contains a halogenated organic compound, the halogenated organic compound having a divalent halogenated hydrocarbon group and an oxygen atom, and the ratio of the number of the oxygen atoms to the number of carbon atoms in the divalent halogenated hydrocarbon group is 0.65 or more.

The present inventors have found that the present solvent has a small environmental impact, is excellent in solubility of raw material compounds, and can improve the yield of the target compound. The reason why the above effects are exhibited is not necessarily clear, but is presumed to be as follows.
This solvent contains a halogenated organic compound having a divalent halogenated hydrocarbon group and an oxygen atom, in which the ratio of the number of oxygen atoms to the number of carbon atoms in the divalent halogenated hydrocarbon group (hereinafter also referred to as the "O/C ratio") is 0.65 or more (hereinafter also referred to as the "specific halogenated organic compound"). By making the O/C ratio 0.65 or more, the polarizability can be improved, and it is presumed that the solubility of the raw material compound in this solvent is improved.
In addition, it is presumed that the improved solubility of the raw material compounds in the solvent improves the efficiency of heat removal in the fluorination reaction, thereby improving the yield of the target compound.

The solvent may contain one or more specific halogenated organic compounds.
The present solvent may or may not contain components other than the specific halogenated organic compound.

The solvent preferably has high solubility for the raw material compounds overall, and is preferably capable of dissolving 10% by mass or more of the raw material compounds at 25°C, more preferably 15% by mass or more, and even more preferably 20% by mass or more.

The boiling point of the solvent (the boiling point of the specific halogenated organic compound when it contains only the specific halogenated organic compound, or the boiling points of each compound when it is a mixed solvent) is preferably 0 to 350°C, more preferably 30 to 300°C, and even more preferably 50 to 250°C. If the boiling point is equal to or higher than the lower limit, it is possible to suppress volatilization due to heat generated during the fluorination reaction, making it easier to recover after the reaction. If the boiling point is equal to or lower than the upper limit, it is easier to remove after the fluorination reaction.

From the viewpoint of achieving a high yield of the target compound, the viscosity of the solvent at 25°C is preferably 10 to 10,000 mPa·s, more preferably 30 to 7,000 mPa·s, and even more preferably 50 to 5,000 mPa·s. The viscosity of the solvent can be measured using a rheometer (e.g., VISCOMETER TV-20, manufactured by Toki Sangyo Co., Ltd.).

(Specific halogenated organic compounds)
The specific halogenated organic compound is preferably a fluoro compound, more preferably a perfluoro compound, from the viewpoint of excellent solubility of the raw material compound and yield of the target compound. In the present disclosure, "perfluoro compound" means a compound that does not have a fluorinable atom or bond, and "fluoro compound" includes perfluoro compounds and compounds that have a fluorinable atom or bond.
From the viewpoint of excellent solubility of the raw material compound and yield of the target compound, the specific halogenated organic compound is preferably an ester compound or an ether compound, more preferably an ether compound, further preferably a fluoroether compound, and particularly preferably a perfluoroether compound.

From the viewpoint of excellent solubility of the raw material compounds and yield of the target compound, the O/C ratio is preferably 0.70 to 2.0, more preferably 0.70 to 1.5, and even more preferably 0.70 to 1.0.
The O/C ratio is measured by ¹⁹ F-NMR.

The divalent halogenated hydrocarbon group preferably has 2 to 6 carbon atoms, and more preferably has 2 to 4 carbon atoms. The halogenated hydrocarbon group may be linear, branched, or cyclic, but is preferably linear.

From the viewpoint of excellent solubility of the raw material compounds and a yield of the target compound, it is preferable that the specific halogenated organic compound has unit structures represented by the following formulas (1) and (2), and the ratio of the number of unit structures represented by formula (2) to the number of unit structures represented by formula (1) is 0.7 or more. From the viewpoint of excellent solubility of the raw material compounds and a yield of the target compound, the above ratio is more preferably 1.0 to 20, further preferably 3.0 to 17, particularly preferably 5.0 to 15, and most preferably 8.0 to 13.
The above ratio can be measured in the same manner as the O/C ratio.

In formula (1), R ^{1 X} represents a divalent halogenated hydrocarbon group having 2 or more carbon atoms, preferably a divalent halogenated hydrocarbon group having 2 to 6 carbon atoms, and more preferably a divalent halogenated hydrocarbon group having 2 to 4 carbon atoms. The halogenated hydrocarbon group may be linear, branched, or cyclic, but is preferably linear from the viewpoints of excellent viscosity characteristics at low temperatures and improving O/C.
In formula (2), each X independently represents a halogen atom, preferably a fluorine atom or a chlorine atom, more preferably a fluorine atom.

The divalent halogenated hydrocarbon group in ^X may be a divalent hydrocarbon group in which one or more halogenatable atoms or bonds in the divalent hydrocarbon group described below are substituted with halogen atoms, and a halogenated alkylene group is preferred. As the halogen atom, a fluorine atom or a chlorine atom is preferred, and a fluorine atom is more preferred.
Halogenatable atoms include hydrogen atoms bonded to carbon atoms. Halogenatable bonds include carbon-carbon unsaturated double bonds and carbon-carbon unsaturated triple bonds.
Examples of the divalent hydrocarbon group include saturated aliphatic hydrocarbon groups such as an alkylene group, a divalent saturated aliphatic hydrocarbon group having a ring structure (a cycloalkylene group, a bicycloalkylene group, a group having an alicyclic spiro structure, a group having any of these groups as a partial structure, etc.); unsaturated aliphatic hydrocarbon groups such as an alkenylene group, an alkynylene group, a cycloalkenylene group, a cycloalkynylene group, a divalent unsaturated aliphatic hydrocarbon group having a ring structure, etc.; and aromatic hydrocarbon groups such as an arylene group, etc., with a saturated aliphatic hydrocarbon group being preferred, and an alkylene group being more preferred.
R ^{1 X} is preferably a perfluoroalkylene group having 2 to 6 carbon atoms, and more preferably a perfluoroalkylene group having 2 to 3 carbon atoms.
Specific examples of R ^X which is a perfluoroalkylene group include CF ₂ CF ₂ , CF ₂ CF ₂ CF ₂ , and CF(CF ₃ ) _CF2 .

The structures represented by formula (1) and formula (2) may be arranged in any of a block, random, or alternating manner.

From the viewpoint of excellent solubility of the raw material compounds and yield of the target compound, it is preferable that the specific halogenated organic compound is represented by the following formula (3).

The details of each symbol in the formula (3) will be explained below.
^A1 and ^A2 each independently represent a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom, and are more preferably monovalent halogenated hydrocarbon groups having 1 to 10 carbon atoms. The halogenated hydrocarbon group may be linear, branched, or cyclic, but is preferably linear.
In this disclosure, "heteroatom" means an atom other than carbon or hydrogen atoms, and includes, for example, nitrogen atoms, oxygen atoms, and sulfur atoms.
Each X independently represents a halogen atom, preferably a fluorine atom or a chlorine atom, more preferably a fluorine atom.
m and n each independently represent an integer of 1 to 200, preferably an integer of 1 to 150, and more preferably an integer of 1 to 100.
n/m is 0.7 or more, more preferably 1.0 to 20, still more preferably 3.0 to 17, particularly preferably 5.0 to 15, and most preferably 8.0 to 13.
The n/m ratio can be measured in the same manner as the O/C ratio.

The monovalent halogenated hydrocarbon group in ^A1 and ^A2 includes a group in which one or more halogenatable atoms or bonds in the monovalent hydrocarbon group described below are substituted with a halogen atom, and a halogenated alkyl group is preferred. As the halogen atom, a fluorine atom or a chlorine atom is preferred, and a fluorine atom is more preferred.
Halogenatable atoms include hydrogen atoms bonded to carbon atoms. Halogenatable bonds include carbon-carbon unsaturated double bonds and carbon-carbon unsaturated triple bonds.
Examples of the monovalent hydrocarbon group include saturated aliphatic hydrocarbon groups such as an alkyl group, a cycloalkyl group, and a monovalent saturated aliphatic hydrocarbon group having a ring structure (a cycloalkyl group, a cycloalkylene group, a bicycloalkyl group, a group having an alicyclic spiro structure, and a group having any of these groups as a partial structure); unsaturated aliphatic hydrocarbon groups such as an alkenyl group, an alkynyl group, a cycloalkenyl group, a cycloalkynyl group, and a monovalent unsaturated aliphatic hydrocarbon group having a ring structure; and aromatic hydrocarbon groups such as an aryl group. Of these, saturated aliphatic hydrocarbon groups are preferred, and alkyl groups are more preferred.
A ¹ and A ² are preferably a perfluoroalkyl group having 1 to 6 carbon atoms, and more preferably a perfluoroalkyl group having 1 to 3 carbon atoms.
Specific examples of perfluoroalkyl groups ^A1 and ^A2 include _{CF3 , CF3CF2 , and CF3CF2CF2 .}

In formula (3), the structure represented by (OCX ₂ CX ₂ ) _m and the structure represented by (OCX ₂ ) _n may be arranged in any of a block, random or alternate manner.

Specific examples of the specific halogenated organic compound include the following compounds. Note that the number of repetitions of each is an average value.
_{CF3OCF2CF2 ( OCF2CF2 ) 30 ( OCF2 ) 30OCF2CF2OCF3 , ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 30 ( OCF2 ) 30OCF2CF2OCF3 , ​ ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 30 ( OCF2 ) 30OCF2CF2OCF2CF3 , ​ ​ ​
CF3OCF2CF2 ( OCF2CF2 ) 20 ( OCF2 ) 40OCF2CF2OCF3 , ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 20 ( OCF2 ) 40OCF2CF2OCF3 , ​ ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 20 ( OCF2 ) 40OCF2CF2OCF2CF3 , ​ ​ ​
CF3OCF2CF2 ( OCF2CF2 ) 15 ( OCF2 ) 45OCF2CF2OCF3 , ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 15 ( OCF2 ) 45OCF2CF2OCF3 , ​ ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 15 ( OCF2 ) 45OCF2CF2OCF2CF3 , ​ ​ ​
CF3OCF2CF2 ( OCF2CF2 ) 12 ( OCF2 ) 48OCF2CF2OCF3 , ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 12 ( OCF2 ) 48OCF2CF2OCF3 , ​ ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 12 ( OCF2 ) 48OCF2CF2OCF2CF3 , ​ ​ ​
CF3OCF2CF2 ( OCF2CF2 ) 8 ( OCF2 ) 64OCF2CF2OCF3 , ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 8 ( OCF2 ) 64OCF2CF2OCF3 , ​ ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 8 ( OCF2 ) 64OCF2CF2OCF2CF3 , ​ ​ ​
CF3OCF2CF2 ( OCF2CF2 ) 6 ( OCF2 ) 66OCF2CF2OCF3 , ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 6 ( OCF2 ) 66OCF2CF2OCF3 , ​ ​
CF3CF2OCF2CF2 ( OCF2CF2 ) 6 ( OCF2 ) 66OCF2CF2OCF2CF3 . ​ ​ ​}

From the viewpoint of achieving an excellent yield of the target compound, the number average molecular weight (Mn) of the specific halogenated organic compound is preferably from 1,000 to 100,000, more preferably from 1,500 to 50,000, and even more preferably from 2,000 to 10,000.
In this disclosure, the Mn of a particular halogenated organic compound is measured in terms of polystyrene by GPC using tetrahydrofuran (THF) as an eluent.

From the viewpoint of excellent solubility of the raw material compounds and yield of the target compound, the content of the specific halogenated organic compound relative to the total mass of the solvent is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably 100% by mass.

(Ingredients other than specific halogenated organic compounds)
The present solvent may contain components other than the specific halogenated organic compound (hereinafter also referred to as "secondary components").
Examples of the minor components include halogenated organic compounds having an O/C ratio of less than 0.65, such as chlorofluorocarbons, perfluoroethers having an O/C ratio of less than 0.65, chlorofluoropolyethers having an O/C ratio of less than 0.65, perfluoroalkylamines, inert fluids, and the like.

From the viewpoint of excellent solubility of the raw material compounds and yield of the target compound, the content of the subcomponents relative to the total mass of the solvent is preferably 10% by mass or less or none, more preferably 5% by mass or less or none, even more preferably 3% by mass or less or none, particularly preferably 1% by mass or less or none, and most preferably none.

(Raw material compound)
The raw material compound for the liquid phase fluorination is an organic compound having at least one fluorinatable atom or bond. The raw material compound may be either a commercially available compound or a synthesized compound.
Atoms that can be fluorinated include hydrogen atoms bonded to carbon atoms, chlorine atoms bonded to carbon atoms, bromine atoms bonded to carbon atoms, and iodine atoms bonded to carbon atoms.
Fluorinizable bonds include carbon-carbon unsaturated double bonds and carbon-carbon unsaturated triple bonds.
The number of fluorinable atoms or bonds in the raw material compound may be at least 1. From the viewpoint of excellent solubility, the number of fluorinable atoms is preferably 1 to 1,000, more preferably 1 to 500. From the viewpoint of increasing the purity of the fluorinated product, the number of fluorinable bonds is preferably 1 to 30, more preferably 1 to 20.

The number of carbon atoms in the raw material compound may be selected depending on the target compound, and is preferably 4 or more, and in one embodiment, 4 to 1,000 is more preferable, 4 to 500 is even more preferable, 4 to 100 is particularly preferable, 4 to 50 is extremely preferable, and 4 to 20 is even more preferable.

In one embodiment, from the viewpoint of improving the yield of the target compound, the raw material compound preferably has a halogen atom, more preferably has at least one selected from the group consisting of a fluorine atom and a chlorine atom, and even more preferably has a fluorine atom. From the viewpoint of improving the solubility in the solvent and the yield of the target compound, the fluorine content in the raw material compound (i.e., the proportion of fluorine atoms in the molecule) is preferably 30% by mass or more, more preferably 30 to 84% by mass, and even more preferably 30 to 76% by mass.

Examples of raw material compounds include aliphatic hydrocarbons, aromatic hydrocarbons, ether compounds, ester compounds, amide compounds, thioether compounds, and thioester compounds. These compounds may be partially halogenated or may not be halogenated. The raw material compounds may be compounds that contain a heteroatom or heteroatom group in the carbon skeleton of these compounds that is not changed by the fluorination reaction. Hereinafter, for convenience, raw material compounds that have both an ester bond and an ether bond will be classified as ester compounds.

The carbon number of the aliphatic hydrocarbon, which is the raw material compound, is preferably 4 or more, and in one embodiment, 4 to 1,000 is more preferable, 4 to 500 is even more preferable, 4 to 100 is particularly preferable, 4 to 50 is extremely preferable, and 4 to 20 is even more preferable. The aliphatic hydrocarbon may be saturated or unsaturated, and may be linear, branched, or cyclic. The aliphatic hydrocarbon may or may not have a substituent other than a halogen atom, and it is preferable that it does not have one.

The number of carbon atoms in the aromatic hydrocarbon raw material compound is preferably 4 or more, and in one embodiment, 4 to 1,000 is more preferable, 4 to 500 is even more preferable, 4 to 100 is particularly preferable, 4 to 50 is extremely preferable, and 4 to 20 is even more preferable. The aromatic hydrocarbon may or may not have a substituent other than a halogen atom. Examples of the substituent include an aliphatic hydrocarbon group having 1 to 100 carbon atoms.

The number of carbon atoms in the amide compound, which is the raw material compound, is preferably 4 or more, and in one embodiment, is more preferably 4 to 1,000, even more preferably 4 to 500, particularly preferably 4 to 100, extremely preferably 4 to 50, and even more preferably 4 to 20. The amide compound is a compound having one or more amide groups. The amide compound may be a polyamide compound.

The carbon number of the thioether compound, which is the raw material compound, is preferably 4 or more, and in one embodiment, is more preferably 4 to 1,000, even more preferably 4 to 500, particularly preferably 4 to 100, extremely preferably 4 to 50, and even more preferably 4 to 20. The thioether compound is a compound having one or more thioether bonds. The thioether compound may be a polythioether compound.

The carbon number of the thioester compound, which is the raw material compound, is preferably 4 or more, and in one embodiment, 4 to 1,000 is more preferable, 4 to 500 is even more preferable, 4 to 100 is particularly preferable, 4 to 50 is extremely preferable, and 4 to 20 is even more preferable. The thioester compound is a compound having one or more thioester bonds. The thioester compound may be a polythioester compound.

The carbon number of the ester compound, which is the raw material compound, is preferably 4 or more, and in one embodiment, 4 to 1,000 is more preferable, 4 to 500 is even more preferable, 4 to 100 is particularly preferable, 4 to 50 is extremely preferable, and 4 to 20 is even more preferable. The ester compound is a compound having one or more ester bonds. The ester compound may be a polyester compound. The ester compound is preferably a monoester compound or a diester compound.

Examples of the ester compound include a compound represented by the following formula (1) and a compound represented by the following formula (2).
R ^A1 -O-(C=O)-R ^B1 ... (1)
R ^B2 -(C=O)-O-R ^A2 -O-(C=O)-R ^B3 ... (2)

In formulas (1) and (2),
R ^A1 , R ^B1 , R ^B2 , and R ^B3 each independently represent a monovalent saturated hydrocarbon group, a halogeno monovalent saturated hydrocarbon group, a heteroatom-containing monovalent saturated hydrocarbon group, or a halogeno (heteroatom-containing monovalent saturated hydrocarbon) group;
R ^A2 is a divalent saturated hydrocarbon group, a halogeno divalent saturated hydrocarbon group, a heteroatom-containing divalent saturated hydrocarbon group, or a halogeno (heteroatom-containing divalent saturated hydrocarbon) group.

In the present disclosure, a "monovalent saturated hydrocarbon group" may be any of a linear alkyl group, a branched alkyl group, and a cycloalkyl group. A "divalent saturated hydrocarbon group" may be any of a linear alkylene group, a branched alkylene group, and a cycloalkylene group. The linear alkyl group, the branched alkyl group, the linear alkylene group, and the branched alkylene group may contain an alicyclic structure.

In this disclosure, "halogeno" means that one or more hydrogen atoms present in the group are replaced with at least one halogen atom selected from a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. Hydrogen atoms may or may not be present in the group.

In this disclosure, a "halogeno monovalent saturated hydrocarbon group" refers to a group in which one or more hydrogen atoms present in a monovalent saturated hydrocarbon group are substituted with a halogen atom. A "halogeno divalent saturated hydrocarbon group" refers to a group in which one or more hydrogen atoms present in a divalent saturated hydrocarbon group are substituted with a halogen atom.

In this disclosure, "heteroatom" means an atom other than a carbon atom or a hydrogen atom, and examples of such atoms include a nitrogen atom, an oxygen atom, and a sulfur atom.

In the present disclosure, a "heteroatom-containing monovalent saturated hydrocarbon group" refers to a group in which a divalent heteroatom or a divalent group containing a heteroatom is contained in a monovalent saturated hydrocarbon group. A "heteroatom-containing divalent saturated hydrocarbon group" refers to a group in which a divalent heteroatom or a divalent group containing a heteroatom is contained in a divalent saturated hydrocarbon group. Examples of divalent heteroatoms include -O- and -S-. Examples of divalent groups containing a heteroatom include -NH-, -C(=O)-, and _-SO2- .

In this disclosure, the term "halogeno (heteroatom-containing monovalent saturated hydrocarbon) group" refers to a group in which one or more hydrogen atoms in the heteroatom-containing monovalent saturated hydrocarbon group have been replaced with a halogen atom. The term "halogeno (heteroatom-containing divalent saturated hydrocarbon) group" refers to a group in which one or more hydrogen atoms in the heteroatom-containing divalent saturated hydrocarbon group have been replaced with a halogen atom.

In formula (1), it is preferable that at least one of R ^A1 and R ^B1 contains a hydrogen atom. Also, in formula (2), it is preferable that at least one selected from the group consisting of R ^A2 , R ^B2 , and R ^B3 contains a hydrogen atom.

[R ^A1 ]
In formula (1), R ^A1 represents a monovalent saturated hydrocarbon group, a halogeno monovalent saturated hydrocarbon group, a heteroatom-containing monovalent saturated hydrocarbon group, or a halogeno (heteroatom-containing monovalent saturated hydrocarbon) group.

Examples of the monovalent saturated hydrocarbon group represented by R ^A1 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, and a cyclohexyl group.

The halogeno monovalent saturated hydrocarbon group represented by R ^A1 is preferably a halogenoalkyl group. The halogen atom contained in the halogeno monovalent saturated hydrocarbon group is preferably a fluorine atom, a chlorine atom or a bromine atom, and more preferably a fluorine atom.

The heteroatom-containing monovalent saturated hydrocarbon group represented by R ^A1 is preferably a monovalent saturated hydrocarbon group containing an ethereal oxygen atom (that is, --O--), and more preferably an alkyl group containing an ethereal oxygen atom.

The halogeno (heteroatom-containing monovalent saturated hydrocarbon) group represented by R ^A1 is preferably a halogeno (heteroatom-containing alkyl group). The halogen atom contained in the halogeno (heteroatom-containing monovalent saturated hydrocarbon) group is preferably a fluorine atom, a chlorine atom, or a bromine atom. The halogeno (heteroatom-containing monovalent saturated hydrocarbon) group is preferably a halogeno monovalent saturated hydrocarbon group containing an ethereal oxygen atom, and more preferably a halogenoalkyl group containing an ethereal oxygen atom.

The carbon number of R ^A1 is preferably 1 to 200, and more preferably 3 to 100, in terms of excellent solubility in a solvent.

In particular, from the viewpoint of excellent solubility in a solvent, R ^is preferably represented by the following formula ( ^A1 ): In other words, R preferably further has an ether bond, and more preferably includes at least one selected from the group consisting of a polyether chain and a fluoropolyether chain.
R ¹¹ O-(R ¹² O) _m1 -R ¹³ - ... (A1)

In formula (A1), R ¹¹ is an alkyl group which may have a fluorine atom, R ¹² is each independently an alkylene group having 1 to 6 carbon atoms which may have a fluorine atom, R ¹³ is an alkylene group having 1 to 6 carbon atoms which may have a fluorine atom, and m1 is an integer from 0 to 500.

In formula (A1), examples of R ¹¹ include an alkyl group and a fluoroalkyl group.

The number of carbon atoms in R ¹¹ is preferably 1 to 100, more preferably 1 to 50, even more preferably 1 to 10, and particularly preferably 1 to 6, from the viewpoint of excellent solubility in a solvent.

The alkyl group represented by R ¹¹ may be a linear alkyl group, a branched alkyl group, or an alkyl group having a ring structure.

The fluoroalkyl group represented by R ¹¹ may be a straight-chain fluoroalkyl group, a branched-chain fluoroalkyl group, or a fluoroalkyl group having a ring structure.

Among these, R ¹¹ is preferably an alkyl group, more preferably a linear alkyl group, and even more preferably a linear alkyl group having 1 to 6 carbon atoms.

In formula (A1), -(R ¹² O) _m1 - is preferably represented by the following formula (A2).
-[(R ^f1 O) _k1 (R ^f2 O) _k2 (R ^f3 O) _k3 (R ^f4 O) _k4 (R ^f5 O) _k5 (R ^f6 O) _k6 ]- ... (A2)
however,
R ^f1 is a fluoroalkylene group having 1 carbon atom;
R ^f2 is a fluoroalkylene group having 2 carbon atoms,
R ^f3 is a fluoroalkylene group having 3 carbon atoms,
R ^f4 is a fluoroalkylene group having 4 carbon atoms,
R ^f5 is a fluoroalkylene group having 5 carbon atoms;
R ^f6 is a fluoroalkylene group having 6 carbon atoms.
k1, k2, k3, k4, k5, and k6 each independently represent an integer of 0 or 1 or more, and k1+k2+k3+k4+k5+k6 is an integer of 0 to 500.

From the viewpoint of excellent solubility in a solvent, k1+k2+k3+k4+k5+k6 is preferably an integer from 1 to 500, more preferably an integer from 1 to 300, even more preferably an integer from 5 to 200, and particularly preferably an integer from 10 to 150.

In addition, the bonding order of (R ^f1 O) to (R ^f6 O) in formula (A2) is arbitrary. k1 to k6 in formula (A2) respectively represent the number of (R ^f1 O) to (R ^f6 O), and do not represent the arrangement. For example, (R ^f5 O) _k5 represents that the number of (R ^f5 O) is k5, and does not represent a block arrangement structure of (R ^f5 O) _k5 . Similarly, the order of (R ^f1 O) to (R ^f6 O) does not represent the bonding order of each unit.

In R ^f3 to R ^f6 , the fluoroalkylene group may be a linear fluoroalkylene group, a branched fluoroalkylene group, or a fluoroalkylene group having a ring structure.

Specific examples of R ^f1 include --CF ₂ -- and --CHF--.

Specific examples of R ^f2 include -CF ₂ CF ₂ -, -CF ₂ CHF-, -CHFCF ₂ -, -CHFCHF-, -CH ₂ CF ₂ -, and -CH ₂ CHF-.

Specific examples of R ^f3 include -CF ₂ CF ₂ CF ₂ -, -CF ₂ CHFCF ₂ -, -CF ₂ CH ₂ CF ₂ -, -CHFCF ₂ CF ₂ -, -CHFCHFCF ₂ -, -CHFCHFCHF-, -CHFCH ₂ CF ₂ -, -CH ₂ CF ₂ CF ₂ -, -CH ₂ CHFCF ₂ -, -CH ₂ CH 2 CF ₂ -, -CH ₂ CF ₂ CHF-, _{-CH 2 CHFCHF-, -CH 2 CH 2 CHF- , -CF} (CF ₃ )-CF ₂ -, -CF(CHF ₂ )-CF ₂ -, -CF(CH ₂ F)-CF ₂ -, -CF( _CH3 ) _-CF2- , -CF(CF3)-CHF-, -CF( _CHF2 )-CHF-, -CF( _CH2F )-CHF-, -CF(CH3) _-CHF- , -CF( _CF3 ) _-CH2- , -CF _{( CHF2} ) _-CH2- , -CF( _CH2F ) _-CH2- , -CF( _CH3 ) _-CH2- , -CH( _CF3 )-CF2- _, -CH
Examples include (CHF ₂ )-CF ₂ -, -CH(CH ₂ F)-CF ₂ -, -CH(CH ₃ )-CF ₂ -, -CH(CF ₃ )-CHF-, -CH(CHF ₂ )-CHF-, -CH(CH ₂ F)-CHF-, -CH(CH ₃ )-CHF-, -CH(CF ₃ )-CH ₂ -, -CH(CHF ₂ )-CH ₂ -, and -CH(CH ₂ F)-CH ₂ -.

Specific examples of R ^f4 include -CF ₂ CF ₂ CF _{2 -} , -CF ₂ CF 2 CF _{2 CHF-, -CF 2 CF 2 CF 2 CH 2 - ,} -CF ₂ CHFCF ₂ CF ₂ -, -CHFCHFCF ₂ CF ₂ -, -CH 2 CHFCF ₂ CF ₂ -, -CF ₂ CH ₂ CF ₂ CF ₂ -, -CHFCH 2 CF ₂ CF ₂ -, -CH ₂ CH ₂ CF ₂ CF _{2 -, -CHFCF 2 CHFCF 2 -, -CH 2 CF 2 CHFCF 2 -, -CF 2 CHFCFCF 2 - , and -CF 2 CHFCFCF 2} -, -CHFCHFCHFCF ₂ -, -CH ₂ CHFCHFCF ₂ -, -CF ₂ CH ₂ CHFCF ₂ -, -CHFCH ₂ CHFCF ₂ -, -CH ₂ CH ₂ CHFCF ₂ -, -CF ₂ CH 2 CH ₂ CF ₂ -, -CHFCH ₂ CH ₂ CF ₂ -, -CH ₂ CH ₂ CH ₂ CF ₂ -, -CHFCH ₂ CH ₂ CHF-, -CH ₂ CH _{2 CH 2 CHF-} , and -cycloC ₄ F ₆ -.

Specific examples of R ^f5 include -CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ -, -CHFCF ₂ CF _{2 CF 2 CF 2} -, -CH ₂ CHFCF ₂ CF ₂ CF ₂ -, -CF ₂ CHFCF ₂ CF ₂ CF ₂ -, -CHFCHFCF ₂ CF ₂ CF ₂ -, -CF ₂ CH ₂ CF ₂ CF ₂ CF ₂ -, -CHFCH ₂ CF ₂ CF ₂ CF ₂ -, -CH ₂ CH ₂ CF ₂ CF ₂ CF ₂ -, -CF ₂ CF ₂ CHFCF ₂ CF ₂ -, -CHFCF ₂ CHFCF ₂ Examples include -CF ₂ -, -CH ₂ CF ₂ CHFCF ₂ CF ₂ -, -CH ₂ CF ₂ CF ₂ CF ₂ CH ₂ -, and -cycloC ₅ F ₈ -.

Specific examples of R ^f6 include -CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ -, -CF ₂ CF ₂ CHFCHFCF ₂ CF ₂ -, -CHFCF ₂ CF ₂ CF ₂ CF ₂ CF ₂ -, -CHFCHFCHFCHFCHFCHF-, -CHFCF ₂ CF ₂ CF ₂ CF _{2 CH 2 -} , -CH ₂ CF ₂ CF ₂ CF _{2 CH 2 -} , and -cycloC ₆ F ₁₀ -.
Here, -cycloC ₄ F ₆ - means a perfluorocyclobutanediyl group, a specific example of which is a perfluorocyclobutane-1,2-diyl group, -cycloC ₅ F ₈ - means a perfluorocyclopentanediyl group, a specific example of which is a perfluorocyclopentane-1,3-diyl group, -cycloC ₆ F ₁₀ - means a perfluorocyclohexanediyl group, a specific example of which is a perfluorocyclohexane-1,4-diyl group.

Among these, —(R ¹² O) _m1 — preferably contains at least one selected from the group consisting of structures represented by the following formulas (F1) to (F3), and more preferably contains a structure represented by formula (F2).
-(R ^f1 O) _k1 -(R ^f2 O) _k2 - ... (F1)
-(R ^f2 O) _k2 -(R ^f4 O) _k4 - ... (F2)
-(R ^f3 O) _k3 - ... (F3)
However, the symbols in formulas (F1) to (F3) are the same as those in formula (A2) above.

In formula (F1) and formula (F2), the bonding order of (R ^f1 O) and (R ^f2 O), and (R ^f2 O) and (R ^f4 O) are each arbitrary. For example, (R ^f1 O) and (R ^f2 O) may be arranged alternately, (R ^f1 O) and (R ^f2 O) may be arranged in blocks, or may be arranged randomly. The same applies to formula (F2).
In formula (F1), k1 is preferably an integer of 1 to 30, and more preferably an integer of 1 to 20. Also, k2 is preferably an integer of 1 to 30, and more preferably an integer of 1 to 20.
In formula (F2), k2 is preferably an integer of 1 to 30, and more preferably an integer of 1 to 20. Also, k4 is preferably an integer of 1 to 30, and more preferably an integer of 1 to 20.
In formula (F3), k3 is preferably an integer of 1 to 30, and more preferably an integer of 1 to 20.

In formula (A1), examples of R ¹³ include the same as R ^f1 to R ^f6 above.

Of these, R ¹³ is preferably a fluoroalkylene group having 1 to 4 carbon atoms.

Specific examples of R ^A1 include the following structures. * represents a bonding site with --O--, n1 represents an integer of 0 to 60, and n2 represents an integer of 0 to 500. n1 is, for example, 13, and n2 is, for example, 7.

[R ^B1 ]
In formula (1), R ^B1 is a monovalent saturated hydrocarbon group, a halogeno monovalent saturated hydrocarbon group, a heteroatom-containing monovalent saturated hydrocarbon group, or a halogeno (heteroatom-containing monovalent saturated hydrocarbon) group.

Examples of the monovalent saturated hydrocarbon group represented by R ^B1 include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, and a cyclohexyl group.

The halogeno monovalent saturated hydrocarbon group represented by R ^B1 is preferably a halogenoalkyl group. The halogen atom contained in the halogeno monovalent saturated hydrocarbon group is preferably a fluorine atom, a chlorine atom, or a bromine atom.

The heteroatom-containing monovalent saturated hydrocarbon group represented by ^R is preferably a monovalent saturated hydrocarbon group containing an ethereal oxygen atom (i.e., -O-), and more preferably an alkyl group containing an ethereal oxygen atom. In other words, R ^preferably further has an ether bond.

The halogeno (heteroatom-containing monovalent saturated hydrocarbon) group represented by R ^B1 is preferably a halogeno (heteroatom-containing alkyl group). The halogen atom contained in the halogeno (heteroatom-containing monovalent saturated hydrocarbon) group is preferably a fluorine atom, a chlorine atom, or a bromine atom. The halogeno (heteroatom-containing monovalent saturated hydrocarbon) group is preferably a halogeno monovalent saturated hydrocarbon group containing an ethereal oxygen atom, and more preferably a halogenoalkyl group containing an ethereal oxygen atom.

The number of carbon atoms in R ^B1 is preferably 1 to 100, more preferably 2 to 50, and even more preferably 3 to 20, from the viewpoint of excellent solubility in a solvent.

From the viewpoint of excellent solubility in a solvent, R ^B1 preferably contains at least one fluorine atom and preferably does not contain a hydrogen atom.

Among these, from the viewpoint of excellent solubility in a solvent, R ^B1 is preferably represented by the following formula (B1).
^R21O- ( ^R22O ) _m2 - ^R23 -... (B1)

In formula (B1), R ²¹ is an alkyl group which may have a fluorine atom, R ²² is each independently an alkylene group having 1 to 6 carbon atoms which may have a fluorine atom, R ²³ is an alkylene group having 1 to 6 carbon atoms which may have a fluorine atom, and m2 is an integer of 0 to 20.

In formula (B1), examples of R ²¹ include an alkyl group and a fluoroalkyl group.

The carbon number of R ²¹ is preferably 1 to 50, more preferably 1 to 10, and even more preferably 1 to 6, from the viewpoint of excellent solubility in a solvent.

The alkyl group represented by ^R21 may be a linear alkyl group, a branched alkyl group, or an alkyl group having a ring structure.
The fluoroalkyl group represented by R ²¹ may be a straight-chain fluoroalkyl group, a branched-chain fluoroalkyl group, or a fluoroalkyl group having a ring structure.

Among these, R ²¹ is preferably a fluoroalkyl group, more preferably a linear fluoroalkyl group, still more preferably a linear fluoroalkyl group having 1 to 6 carbon atoms, and particularly preferably a linear perfluoroalkyl group having 1 to 6 carbon atoms.

In formula (B1), —(R ²² O) _m2 — is preferably represented by the above formula (A2).

In formula (B1), m2 is preferably 0 to 15, more preferably 0 to 10, even more preferably 0 to 4, and particularly preferably 0 to 2.

In formula (B1), examples of R ²³ include the same as R ^f1 to R ^f6 above.

Among these, R ²³ is preferably a fluoroalkylene group having 1 to 3 carbon atoms, and more preferably a perfluoroalkylene group having 1 to 3 carbon atoms.

Specific examples of R ^B1 include the following structures: * represents the bonding site with -O-(C=O)-.

[R ^A2 ]
In formula (2), R ^A2 is a divalent saturated hydrocarbon group, a halogeno divalent saturated hydrocarbon group, a heteroatom-containing divalent saturated hydrocarbon group, or a halogeno (heteroatom-containing divalent saturated hydrocarbon) group.

Examples of the divalent saturated hydrocarbon group, halogeno divalent saturated hydrocarbon group, heteroatom-containing divalent saturated hydrocarbon group, or halogeno (heteroatom-containing divalent saturated hydrocarbon) group represented by ^R include groups in which one hydrogen atom or one halogen atom has been removed from the monovalent saturated hydrocarbon group, halogeno monovalent saturated hydrocarbon group, heteroatom-containing monovalent saturated hydrocarbon group, or halogeno (heteroatom-containing monovalent saturated hydrocarbon) group represented by R in ^{formula (} 1).

The carbon number of R ^A2 is preferably 1 to 200, and more preferably 3 to 100, in terms of excellent solubility in a solvent.

Among these, from the viewpoint of excellent solubility in a solvent, R ^A2 is preferably represented by the following formula (A5): In other words, R ^A2 preferably further has an ether bond, and more preferably includes at least one selected from the group consisting of a polyether chain and a fluoropolyether chain.
-R ³¹ O-(R ³² O) _m5 -R ³³ - ... (A5)

In formula (A5), R ³¹ and R ³³ each independently represent an alkylene group having 1 to 6 carbon atoms which may have a fluorine atom, R ³² each independently represent an alkylene group having 1 to 6 carbon atoms which may have a fluorine atom, and m5 is an integer of 0 to 500.

In formula (A5), R ³¹ and R ³³ each independently have the same meaning as R ¹³ in formula (A1).
In formula (A5), examples of -(R ³² O) _m5 - include the same as -(R ¹² O) _m1 - in formula (A1).

Specific examples of R ^A2 include the following structures: * represents a bonding site with —O—, and n2 represents an integer of 0 to 500.

[R ^B2 and R ^B3 ]
In formula (2), R ^B2 and R ^B3 each independently represent a monovalent saturated hydrocarbon group, a halogeno monovalent saturated hydrocarbon group, a heteroatom-containing monovalent saturated hydrocarbon group, or a halogeno (heteroatom-containing monovalent saturated hydrocarbon) group.

Examples of the monovalent saturated hydrocarbon group, halogeno monovalent saturated hydrocarbon group, heteroatom-containing monovalent saturated hydrocarbon group, or halogeno (heteroatom-containing monovalent saturated hydrocarbon) group represented by R ^{or R} include groups similar to the monovalent saturated hydrocarbon group, halogeno monovalent saturated hydrocarbon group, heteroatom-containing monovalent saturated hydrocarbon group, or halogeno (heteroatom-containing monovalent saturated hydrocarbon) group represented by R in ^formula (1).

An example of an ester compound is compound T1 below.

The carbon number of the ether compound, which is the raw material compound, is preferably 4 or more, and in one embodiment, 4 to 1,000 is more preferable, 4 to 500 is even more preferable, 4 to 100 is particularly preferable, 4 to 50 is extremely preferable, and 4 to 20 is even more preferable. The ether compound is a compound having one or more ether bonds. The ether compound may be a polyether compound.

In one embodiment, the ether compound has the structure:
R ^x -O-R ^Y

In the formula,
R ^x and R ^Y are each independently a monovalent saturated hydrocarbon group, a halogeno monovalent saturated hydrocarbon group, a heteroatom-containing monovalent saturated hydrocarbon group, or a halogeno (heteroatom-containing monovalent saturated hydrocarbon) group, provided that at least one of R ^x and R ^Y has at least one fluorinable atom or bond.

Details of the monovalent saturated hydrocarbon group, the halogeno monovalent saturated hydrocarbon group, the heteroatom-containing monovalent saturated hydrocarbon group, and the halogeno (heteroatom-containing monovalent saturated hydrocarbon) group are the same as those described in the section on the compound represented by formula (1), which is the raw material compound, that is, the ester compound.

Examples of the monovalent saturated hydrocarbon groups represented by ^Rx and ^Ry each independently include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a 2-ethylhexyl group, and a cyclohexyl group.

The halogeno monovalent saturated hydrocarbon groups represented by R ^x and R ^Y are each independently preferably a halogenoalkyl group. The halogen atom contained in the halogeno monovalent saturated hydrocarbon group is preferably a fluorine atom, a chlorine atom, or a bromine atom, and more preferably a fluorine atom.

The heteroatom-containing monovalent saturated hydrocarbon group represented by R ^x and R ^Y is preferably a monovalent saturated hydrocarbon group containing an ethereal oxygen atom (i.e., —O—), and more preferably an alkyl group containing an ethereal oxygen atom.

The halogeno (heteroatom-containing monovalent saturated hydrocarbon) groups represented by ^Rx and ^Ry are each preferably independently a halogeno (heteroatom-containing alkyl) group. The halogen atom contained in the halogeno (heteroatom-containing monovalent saturated hydrocarbon) group is preferably a fluorine atom, a chlorine atom, or a bromine atom. The halogeno (heteroatom-containing monovalent saturated hydrocarbon) group is preferably a halogeno monovalent saturated hydrocarbon group containing an ethereal oxygen atom, and more preferably a halogenoalkyl group containing an ethereal oxygen atom.

The carbon number of R ^x and R ^Y is each independently preferably 1 to 1,000, more preferably 1 to 500, and even more preferably 1 to 300, from the viewpoint of excellent solubility in a solvent.

From the viewpoint of viscosity, the content of the raw material compound contained in the liquid is preferably 10 to 100% by mass, more preferably 15 to 70% by mass, and even more preferably 20 to 50% by mass, based on the total mass of the liquid.

Specific examples of raw material compounds include the following compounds listed in WO 2000/056694 and WO 2002/004397. In the formula, Cy represents a cyclohexyl group, Ph represents a phenyl group, and d, e, f, k, and r represent integers of 1 or more.

_{CF3CF2COOCH2CH2CH3 , ​ ​ ​
CF3CF2COOCH2CH ( OCH2CH2CH3 ) CH3 , ​
CF3CF2COOCH2CH ( OCH2CH2CHClCH2Cl ) CH3 , ​
CF3CF2COO ( CH2 ) 4OCHClCH2Cl
CF3CF2COO} ( _{CH2 ) 5OCHClCH2Cl ,
CF3} ( _{CF3CF2CF2O )} CFCOO( _{CH2 ) 4OCHClCH2Cl ,
CF3} ( _{CF3CF2CF2O )} CFCOO _{( CH2} ) _{5OCHClCH2Cl ,
CF3 ( CF2ClCFClCF2CF2O ) CFCOOCH2CH ( OCH2CH2CHClCH2Cl} ) _{CH3 ,
CF2ClCFClOCF2CF2CF2COO ( CH2 ) 4OCHClCH2Cl , ​
CClF2COOCH2CH2Cl , ​
CBrF2COOCH2CH2Br , ​
CF2BrCF2OCF} ( _CF3 ) _{COOCH2CH ( OCH2CH2Br} ) _{CH3 ,
CF2ClCFClCF2CF ( CF3} )OCF( _CF3 )COOCH2CH[OCH( _{CH3 ) CHClCH2Cl} ] _CH3 ,
_{CH2ClCHClCH2COOCH2CF2CFClCF2Cl , ​ ​ ​
CF3 ( CH3CH2CH2O ) CFCOOCH2CF ( OCF2CF2CF3 )} CF3 _,
CF3 ( _{CH3CH2CH2O ) CFCOOCH2CF ( OCH2CH2CH3 ) CF3 .}

_CF3 ( _{CF3CF2CF2O ) CFCOOCH2CH ( OCH2CH2CH3 ) CH3 ,
CF3 ( CF3CF2CF2O} ) _{CFCOOCH2CH ( OCH2CH2CHClCH2Cl ) CH3 ,
CF3} ( _CF3CF2CF2O ) _{CFCOOCH2CH ( OCH2Cy} ) _{CH3 ,
CF3} ( _{CF3CF2CF2O ) CFCOOCH2CH ( OCH2Ph} ) _CH3 ,
_CF3 ( _{CF3CF2CF2O ) CFCOOCH2CH} (O( _CH2 ) _{9CH3 ) CH3 ,
CF3} ( _{CF3CF2CF2O )} CFCOO _{( CH2 ) 3OCH2Ph} ,
_CF3 ( _{CF3CF2CF2O ) CFCOO} ( _{CH2 ) 3OCH2CH} = _CH2 ,
_{CF3CF2COOCH2CH2CHClCH2Cl , ​ ​ ​
CF2ClCFClCF2COOCH2CH2CHClCH2Cl , ​ ​ ​
CF2ClCF2CFClCOOCH2CH2CHClCH2Cl , ​ ​ ​}

_{CF3CF2COO ( CH2 ) dOCOCF2CF3 ,
CF3CF2COO} [ _{CH2CH ( CH3} )O] _e ( _{CH2 ) fOCOCF2CF3 ,
CF3CF2COO ( CH2CH2O ) k} ( _{CH2 ) rOCOCF2CF3 ,
CF3CF2COO} ( _CH2 ) _{2O ( CH2 ) 2OCOCF2CF3 ,
CF3CF2CF2OCF ( CF3} ) _COOCH2CH ( _CH3 ) _O ( _CH2 )5OCOCF _{( CF3 ) OCF2CF2CF3 ,
CF3CF2COO} ( _CH2 ) _{2O ( CH2} ) _2OCH ( _{CH3 ) CH2OCOCF2CF3 .}

_{CF3O ( CF2CFHOCF2CF2CF2CH2O ) dCF2CFHOCF2CF2CF2CH2OCOCF ( CF3 ) OCF2CF2CF3 , ​ ​ ​ ​ ​ ​
CH2ClCHClCH2OCF2CHFCl , ​
CF3CF2CF2OCF ( CF3 ) COOCH2CH2CH2CH2OCOCF ( CF3 ) OCF2CF2CF3 , ​ ​
CH3CH2OCH2CH2OCH2CH2OCOCCF ( CF3 ) OCF2CF ( CF3 ) OCF2CF2CF3 , ​ ​
( CF3 ) 2CFCOOCH2CH2CH2CH2CH2CH2OCOCF ( CF3 ) 2 ,
CH3CH2CH2CH2OCOCF ( CF3 ) OCF2CF2CF3 . ​ ​}

Examples of raw material compounds include compounds described as substrates for fluorination reactions in Journal of Fluorine Chemistry Volume 174, June 2015, Pages 120-131, Marie Pierre Krafft, Jean G. Riess, Perfluorocubane‐a tiny electron guzzler, Science, 377, 6607, (709-709), (2022).

From the viewpoint of improving the yield of the target compound, the boiling point of the raw material compound is preferably 0°C or higher, more preferably 30°C or higher, and even more preferably 50°C or higher. The upper limit of the boiling point is not particularly limited, but can be 300°C or lower. In this disclosure, the "boiling point" refers to the boiling point at normal pressure (760 mmHg).

The molecular weight of the raw material compound is not particularly limited and can be selected according to the type of the target compound. The molecular weight of the raw material compound is preferably 100 to 20,000, more preferably 150 to 10,000, and even more preferably 200 to 5,000. If the molecular weight is equal to or greater than the lower limit, the decomposition reaction in the gas phase during liquid phase fluorination is likely to be suppressed. If the molecular weight is equal to or less than the upper limit, the target compound is likely to be purified.
When the molecular weight has a distribution, the molecular weight indicates Mn.
The Mn of the above-mentioned raw material compound is a value calculated from the molecular structure identified by ¹ H-NMR and ¹⁹ F-NMR.

(Target compound)
The target compound, a fluorine-containing compound, is a compound in which all of the fluorinatable atoms or bonds of the raw material compound are fluorinated. In liquid-phase fluorination, a fluorine-containing compound having a structure corresponding to the carbon skeleton of the raw material compound is produced. However, when the raw material compound has carbon-carbon unsaturated bonds, a fluorine atom may be added to one or more of the unsaturated bonds to change the bonding state.

Examples of the target compound include fluorinated compounds of the compounds exemplified in the section on raw material compounds. Therefore, examples of the target compound include fluorinated aliphatic hydrocarbons, aromatic hydrocarbons, ether compounds, ester compounds, thioether compounds, sulfonamide compounds, urea compounds, thiourea compounds, urethane compounds, carbonate compounds, amine compounds, amide compounds, etc. The target compound may also be a compound containing a heteroatom or a heteroatom group in the carbon skeleton of these compounds that is not changed by the fluorination reaction.
Among them, specific examples of useful target compounds include perfluoroalkanes, perfluoroether compounds, perfluoropolyether compounds, chlorofluorocarbons, chlorofluoroether compounds (CFE-419, etc.), chlorofluoropolyether compounds, and perfluorosulfonic acid fluorides.

"Target compound" does not necessarily mean the final target product. The target compound, a fluorine-containing compound, can be useful as it is or by being chemically converted into another compound.

[Method of producing fluorine-containing compounds]
The method for producing a fluorine-containing compound according to the present disclosure (hereinafter also referred to as "the present production method") includes a step of fluorinating an organic compound (raw material compound) having at least one fluorinatable atom or bond in the above-described present solvent into which fluorine gas has been introduced (hereinafter also referred to as "the fluorination step").
The solvent and the raw material compounds are not described here because they have been described above. Also, the fluorine-containing compound (target compound) obtained by this production method is not described here because it has been described above.

The fluorination process may be carried out by a batch method or a continuous method, with the continuous method being preferred. Examples of the fluorination method include fluorination methods 1 and 2 described below.

Fluorination method 1: A reactor is charged with the raw material compounds and the present solvent, and stirring is started. The reaction is carried out at a given reaction temperature and pressure while continuously supplying fluorine gas.
Fluorination method 2: The solvent is charged into a reactor and stirring is started. The raw material compound and fluorine gas are continuously and simultaneously fed at a predetermined molar ratio under a predetermined reaction temperature and pressure.

When the raw material compound is supplied in fluorination method 2, the raw material compound may be supplied as is without being diluted with the present solvent. When the raw material compound is diluted with the present solvent, the amount of the solvent is preferably at least 1-fold by mass, and more preferably at least 2-fold by mass, relative to the raw material compound.

The fluorine gas may be used as a mixed gas diluted with an inert gas such as nitrogen gas. From the viewpoint of excellent conversion, the concentration of fluorine gas in the mixed gas is preferably 10% by volume or more, more preferably 15% by volume or more, and even more preferably 20% by volume or more. From the viewpoint of suppressing decomposition of the raw material compound, the concentration is preferably 60% by volume or less, more preferably 50% by volume or less, and even more preferably 40% by volume or less.

From the viewpoint of excellent conversion, the amount of fluorine used in the liquid-phase fluorination is preferably an amount that is an excess equivalent of fluorine relative to the hydrogen atoms in the raw material compound, and more preferably an amount that is 1.5 times equivalent (i.e., 1.5 times molar). The amount of fluorine is preferably such that an excess equivalent is maintained from the beginning to the end of the liquid-phase fluorination.

The reaction temperature for the liquid phase fluorination is preferably −60° C. or higher and the boiling point of the raw material compound or lower, and from the viewpoints of reaction yield, selectivity, and ease of industrial implementation, is more preferably −50° C. to +100° C., and further preferably −20° C. to +50° C.
The reaction pressure for the liquid phase fluorination is not particularly limited, but from the viewpoints of reaction yield, selectivity, and ease of industrial implementation, it is preferably 0 to 2 MPa.

The reaction time in liquid phase fluorination (i.e., the time it takes for the raw material compound to pass through the reaction field) is preferably 200 hours or less, more preferably 190 hours or less, even more preferably 170 hours or less, particularly preferably 150 hours or less, and extremely preferably 100 hours or less. The reaction time is preferably 0.3 hours or more, more preferably 0.6 hours or more, and even more preferably 1 hour or more.

The amount of the solvent used is preferably 1 time by mass or more, more preferably 5 times by mass or more, and even more preferably 10 times by mass or more, relative to the raw material compound. The amount of the solvent used may be 100 times by mass or less, 70 times by mass or less, or 50 times by mass or less, relative to the raw material compound.

In order to efficiently proceed with the liquid phase fluorination, a compound having a C--H bond or a compound having a carbon-carbon double bond may be added as an auxiliary.
The auxiliary compound having a C-H bond is preferably an aromatic hydrocarbon, more preferably benzene, toluene, etc. The amount of the compound having a C-H bond added is preferably 0.1 to 10 mol %, more preferably 0.1 to 5 mol %, based on the hydrogen atoms of the raw material compound.
Examples of the auxiliary compound having a carbon-carbon double bond include CF ₃ CF═CF ₂ and CF ₂ ═CF-CF═CF ₂ .
The amount of the compound having a carbon-carbon double bond added is preferably 0.1 to 100 mol %, more preferably 0.1 to 50 mol %, based on the hydrogen atoms in the raw material compounds.

For example, in a batch reaction, an auxiliary may be added to the reaction system in the later stages of liquid phase fluorination. The auxiliary is preferably added in a state where fluorine is present in the reaction system. When the auxiliary is added, it is preferable to pressurize the reaction system. The pressure during pressurization is preferably 0.01 to 5 MPa.

In the liquid-phase fluorination of raw material esterification, if a reaction occurs in which hydrogen atoms are replaced by fluorine atoms, HF is produced as a by-product. To capture HF, it is preferable to either have an HF scavenger present in the reaction system or to bring the HF scavenger into contact with the outlet gas at the reactor gas outlet. For example, NaF is a preferred HF scavenger.

The crude product containing the fluorine-containing compound obtained by liquid-phase fluorination may be used as is in the next step, or may be purified to a high purity. Examples of purification methods include distilling the crude product directly under normal or reduced pressure.

Next, the embodiments of the present disclosure will be specifically described using examples, but the embodiments of the present disclosure are not limited to these examples. In this disclosure, Examples 2 to 7 and 11 are examples, and Examples 1 and 8 to 10 are comparative examples.

(Example 1)
300 g of halogenated organic compound A was added to a 500 mL nickel autoclave, stirred, and cooled to 0°C.
The atmosphere inside the autoclave was replaced with nitrogen gas, and then replaced again with fluorine gas diluted to 20 volume % with nitrogen gas (hereinafter referred to as "20 volume % fluorine gas"), and the raw material compound 1 solution was continuously added slowly at a constant rate simultaneously with the 20 volume % fluorine gas.
Halogenated organic compound A: A compound represented by formula (A), in which A ¹¹ and A ¹² are each independently a mixture of CF ₃ and CF ₃ CF _2. In addition, in the formula, m11, n11, n11/m11 (m11 and n11 are average values), Mn, and O/C ratio are as shown in Table 1.
A ¹¹ (OCF ₂ CF ₂ ) _m11 (OCF ₂ ) _n11 OA ¹² (A)
Raw material compound ₁ : _{( CF3} ) _{2CFCOOCH2CH2CH2CH2CH2OCOCF ( CF3 ) 2 .}
Raw material compound 1 solution: 5.0 g of raw material compound 1 was dissolved in 50 g of halogenated organic compound A.

Benzene was added to halogenated organic compound A to obtain solution A having a benzene concentration of 0.2 mass %.
While blowing 20% by volume of fluorine gas into the autoclave, solution A was injected in several portions.
Thereafter, the atmosphere inside the autoclave was replaced with nitrogen gas, and the reaction solution was then extracted.
The resulting reaction solution was concentrated by an evaporator, and the product was quantitatively analyzed by ¹⁹ F-NMR and ¹ H-NMR, revealing that the amount of fluorine-containing compound A recovered was 0.3 g (yield: 5%).
Fluorine _- containing compound A _{: ( CF3 ) 2CFOCF2CF2CF2CF2CF2CF2OCOCF ( CF3} ) ₂

(Examples 2 to 7)
Fluorine-containing compound A was obtained in the same manner as in Example 1, except that halogenated organic compound A was changed to specific halogenated organic compounds B to G shown in Table 1. The recovery amount and yield of fluorine-containing compound A are shown in Table 1.
Specific halogenated organic compounds B to G: Compounds represented by formula (3), in which A ¹¹ and A ¹² are each independently a mixture of CF ₃ and CF ₃ CF _2. In the formula, m11, n11, n11/m11 (m11 and n11 are average values), Mn, and O/C ratio are as shown in Table 1.

(Example 8)
A fluorine-containing compound A was obtained in the same manner as in Example 1, except that the halogenated organic compound A was changed to the halogenated organic compound H.
Halogenated organic compound H: CF ₃ CF ₂ O-(CF ₂ CF ₂ CF ₂ O) _p1 -CF ₂ CF ₃ (p1=20, p1 represents an average value. Mn is 3,300.) The O/C ratio was 0.33.

(Example 9)
A fluorine-containing compound A was obtained in the same manner as in Example 1, except that the halogenated organic compound A was changed to the halogenated organic compound I.
Halogenated organic compound I: CF ₃ CF ₂ CF ₂ O-(CF(CF ₃ )CF ₂ O) _p2 -CF ₂ CF ₂ CF ₃ (p2=13, p2 represents an average value, Mn 2,500). The O/C ratio was 0.33.

(Example 10)
A fluorine-containing compound A was obtained in the same manner as in Example 1, except that the halogenated organic compound A was changed to the halogenated organic compound J.
Halogenated organic compound J: CF ₃ O-(CF ₂ CF(CF ₃ )O) _p3 (CF ₂ O) _q -A ²⁰ (p3=15, q=15, p3 and q represent average values. Mn 3,500, A ²⁰ is a compound which is a mixture of CF ₃ , CF ₃ CF ₂ , and CF ₃ CF ₂ CF ₂ ). The O/C ratio was 0.50.

(Example 11)
_A fluorine-containing compound B _{was obtained} in the same manner as in Example 6, except that the raw material compound 1 was changed to _{CH3CH2CH2CH2OCOCF} ( _CF3 ) _OCF2CF2CF3 (raw material compound 2). The recovered amount was _{6.5 g} (yield 91%).
The structure of the fluorine-containing compound B is as follows:
_{Fluorine - containing} compound B _{: CF3CF2CF2CF2OCOCF} ( _{CF3 ) OCF2CF2CF3}

<Solubility>
In Examples 1 to 11, solubility was evaluated separately from fluorination. Specifically, the raw material compound and the halogenated organic compound or the specific halogenated organic compound were placed in a vial so that the raw material compound was 5, 10, 15, 20, or 25% by mass, and stirred. The vial was kept at 25°C. A laser was irradiated onto the vial, and it was visually confirmed whether or not the particles were dispersed, and the solubility was evaluated according to the following evaluation criteria. The results are shown in Table 1.
(Evaluation criteria)
A: No particle dispersion was observed even when the raw material compound was 20% by mass or more. B: No particle dispersion was observed when the raw material compound was 10% by mass or more or less than 20% by mass, but particle dispersion was observed when the raw material compound was 20% by mass or more. C: No particle dispersion was observed when the raw material compound was less than 10% by mass. D: Particle dispersion was observed even when the raw material compound was less than 10% by mass.

As shown in Table 1, it was confirmed that the use of a solvent containing a specific halogenated organic compound results in excellent solubility of the raw material compound. It was also confirmed that the fluorination yield is excellent.

The solvent of the present disclosure has a low environmental impact and excellent solubility of raw material compounds in the fluorination of organic compounds having at least one fluorinatable atom or bond, and can improve the yield of the target compound. The obtained fluorine-containing compound can be derived into fluorine-containing compounds having various functional groups (e.g., hydroxyl groups, ethylenically unsaturated groups, epoxy groups, carboxy groups, etc.). In addition, the obtained fluorine-containing compound and fluorine-containing compounds that can be derived from the fluorine-containing compound can be used as surface treatment agents, emulsifiers, rubber, surfactants, solvents, heat transfer media, pharmaceuticals, agricultural chemicals, lubricants, intermediates thereof, etc.

Claims (9)

A solvent for use in the fluorination of an organic compound having at least one fluorinatable atom or bond, said solvent comprising a halogenated organic compound,
the halogenated organic compound has a divalent halogenated hydrocarbon group and an oxygen atom,
A solvent in which the ratio of the number of oxygen atoms to the number of carbon atoms in the halogenated hydrocarbon group is 0.65 or more. The halogenated organic compound has a unit structure represented by the following formula (1) and formula (2):
2. The solvent according to claim 1, wherein the ratio of the number of unit structures represented by formula (2) to the number of unit structures represented by formula (1) is 0.7 or more.

In formula (1),
R ^X represents a divalent halogenated hydrocarbon group having 2 or more carbon atoms;
In formula (2),
Each X independently represents a halogen atom. The solvent according to claim 1 or 2, wherein the halogenated hydrocarbon group is a linear hydrocarbon group. The solvent according to claim 1 or 2, wherein the halogenated organic compound is represented by the following formula (3):

In formula (3),
A ¹ and A ² each independently represent a monovalent halogenated hydrocarbon group having 1 to 20 carbon atoms which may contain a heteroatom;
Each X independently represents a halogen atom.
m and n each independently represent an integer of 1 to 200;
n/m is 0.7 or more. The solvent according to claim 1 or 2, wherein the halogenated organic compound is a perfluoro compound. The solvent according to claim 1 or 2, wherein the halogenated organic compound is a perfluoroether compound. The solvent according to claim 1 or 2, wherein the number average molecular weight of the halogenated organic compound is 1,000 to 100,000. The solvent according to claim 1 or 2, wherein the organic compound having at least one fluorinable atom or bond is an ester compound. 3. A method for producing a fluorine-containing compound, comprising the step of fluorinating an organic compound having at least one fluorinatable atom or bond in the solvent according to claim 1 or 2 into which fluorine gas has been introduced.