Fluorine-containing diether compounds

Abstract

This invention provides novel fluorine-containing diether compounds. [Solution] Formula (1) below: JPEG2026065628000011.jpg30128 (In formula (1), R1 represents a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms, R2 may be the same or different, consisting of a methyl group, an ethyl group, -CH2CF3, or -CH2(C2F4). n Showing H n represents an integer between 1 and 10 (inclusive). A fluorine-containing diether compound represented by the following:

Description

Technical Field

[0001] The present disclosure relates to fluorinated diether compounds.

Background Art

[0002] In recent years, hydrofluoroethers (HFEs) have attracted attention as alternatives to chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) because of their low global warming potential (GWP) and ozone depletion potential (ODP).

[0003] Patent Document 1 discloses an azeotrope-like composition containing a blend of (a) 1,1,1,2,3,3-hexafluoro-3-methoxy-propane (HFE-356mec) and (b) 1-bromopropane, the blend boiling at less than about 54.2 °C at about 101 kilopascals (760 torr), and consisting essentially of 0.1 to about 42 weight percent 1-bromopropane and 58 to about 99.9 weight percent 1,1,1,2,3,3-hexafluoro-3-methoxy-propane.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0007] According to the present disclosure, a novel fluorinated diether compound can be provided.

Brief Description of the Drawings

[0008] [Figure 1] It is the mass spectrum obtained as a result of gas chromatography-mass spectrometry (GC-MS) of the fluorinated diether compound A obtained in Example 1.

Modes for Carrying Out the Invention

[0009] Hereinafter, preferred embodiments of the present disclosure will be described in detail. The description of the constituent elements described below is based on representative embodiments and specific examples, but the present disclosure is not limited to such embodiments and specific examples.

[0010] In this specification, "containing" is a concept that includes any of "comprise", "consist essentially of", and "consist of".

[0011] In the numerical ranges described stepwise in this specification, the upper limit value or lower limit value of a certain numerical range can be arbitrarily combined with the upper limit value or lower limit value of another numerical range. Also, in the numerical ranges described in this specification, the upper limit value or lower limit value of the numerical range may be replaced with the value shown in the examples or a value uniquely derivable from the examples. Further, in this specification, numerical values connected by "~" mean a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value.

[0012] In this specification, gauge pressure is the relative pressure based on atmospheric pressure (0.1013 MPa), and means the pressure difference obtained by subtracting atmospheric pressure from the absolute pressure. In this specification, gauge pressure is denoted with "G" attached, such as MPaG. On the other hand, when "G" is not attached, it means atmospheric pressure.

[0013] The present disclosure includes the following embodiments.

[0014] The fluorine-containing diether compound of the present disclosure is a compound represented by the following formula (1).

Chemical formula

[0015] In formula (1), R1 represents a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms.

[0016] In formula (1), R2 is the same or different and is a methyl group, an ethyl group, -CH2CF3, or -CH2(C2F4) n H.

[0017] In formula (1), n represents an integer of 1 or more and 10 or less.

[0018] In formula (1), R1 is preferably a fluorine atom or a perfluoroalkyl group having 1 to 5 carbon atoms.

[0019] In formula (1), the two R2s may be the same or different. In formula (1), the two R2s are preferably the same.

[0020] In formula (1), n is preferably an integer of 1 or more and 5 or less.

[0021] In formula (1), R2 is preferably the same or different and is a methyl group, an ethyl group, or -CH2CF3.

[0022] In formula (1), it is preferable that R1 is a fluorine atom or -CF3 and R2 is the same or different and is a methyl group or -CH2CF3.

[0023] In formula (1), (i) R1 is -CF3 and R2 is a methyl group, or (ii) it is more preferable that R1 is a fluorine atom and R2 is -CH2CF3.

[0024] In formula (1), it is particularly preferable that R1 is -CF3 and R2 is a methyl group.

[0025] The fluorine-containing diether compound represented by formula (1) can be produced by reacting a fluorine-containing olefin compound represented by formula (3) below with an alcohol compound represented by R2-OH (hereinafter also referred to as the "first alcohol compound") in the liquid phase.

[0026] [ka]

[0027] In formula (3), R1 is synonymous with R1 of the fluorine-containing diether compound represented by formula (1).

[0028] In the first alcohol compound, R2 is synonymous with R2 in the fluorine-containing ether compound represented by formula (2).

[0029] The following describes in detail a method for producing the fluorine-containing diether compound represented by formula (1) of this disclosure. The fluorine-containing diether compound represented by formula (1) can preferably be produced by carrying out the following steps (1), (2), (3), and (4) in this order. Step (1): Add an aqueous solution of alkali metal hydroxide and the first alcohol compound to the container and evacuate the gas phase. Step (2): While stirring the liquid phase of the container, the fluorine-containing olefin compound represented by formula (3) above is supplied to the container after vacuuming, and then stirred further. Step (3): Wash the lower layer obtained after stirring with sulfuric acid. Step (4): The lower layer after washing is rectified to separate the fluorine-containing ether compound represented by formula (2), which includes the fluorine-containing diether compound represented by formula (1).

[0030] In step (1), examples of containers include stainless steel containers.

[0031] In step (1), the amount of aqueous solution of alkali metal hydroxide used is preferably 50 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of the fluorine-containing olefin compound represented by formula (3) used in step (2).

[0032] In step (1), the amount of the first alcohol compound used is preferably 20 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of the fluorine-containing olefin compound represented by formula (3) used in step (2).

[0033] In step (1), the aqueous solution of alkali metal hydroxide is preferably an aqueous solution containing 1% by mass or more and 10% by mass or less of alkali metal hydroxide. Examples of alkali metal hydroxides include sodium hydroxide, potassium hydroxide, lithium hydroxide, and the like.

[0034] The alkali metal hydroxide is preferably sodium hydroxide or potassium hydroxide.

[0035] In step (1), the first alcohol compound can be, for example, methanol, ethanol, n-propyl alcohol, iso-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, or tert-butyl alcohol.

[0036] The first alcohol compound is preferably methanol or ethanol.

[0037] In step (2), the temperature at which the fluorine-containing olefin compound represented by formula (3) is supplied is preferably 0°C or higher and 10°C or lower.

[0038] In step (2), the pressure at which the fluorine-containing olefin compound represented by formula (3) is supplied is preferably between -0.05 MPaG and 0.30 MPaG.

[0039] In step (2), the time for supplying the fluorine-containing olefin compound represented by formula (3) is preferably 1 hour or more and 10 hours or less.

[0040] In step (2), the temperature during stirring is preferably 10°C or higher and 30°C or lower.

[0041] In step (2), the stirring time is preferably 1 hour or more and 30 hours or less.

[0042] In step (4), the temperature at which rectification is performed is preferably 50°C to 90°C.

[0043] In step (4), the residence time during rectification is preferably 0.5 hours or more and 8 hours or less.

[0044] In step (4), the pressure used for rectification is preferably between -0.08 MPaG and 0.12 MPaG.

[0045] The fluorine-containing diether compounds of this disclosure are particularly preferably compounds represented by the following formula (1A). [ka]

[0046] The fluorine-containing diether compound represented by formula (1A) (molecular weight = 194) is a novel compound not previously documented in the literature.

[0047] The fluorine-containing diether compound represented by formula (1A) can be produced by reacting hexafluoropropylene with methanol in the liquid phase.

[0048] The method for producing the fluorine-containing diether compound represented by formula (1A) will be described in detail below.

[0049] Examples of methods for producing the fluorine-containing diether compound represented by formula (1A) of this disclosure include production method A and production method B.

[0050] Manufacturing method A is a manufacturing method that performs the following steps (1a), (2a), (3a), (4a), and (5a) in this order. Step (1a): Add potassium hydroxide, methanol, and HFE-356mec to the container and evacuate the gas phase. Step (2a): While stirring the liquid phase of the container, hexafluoropropylene is supplied into the vacuum-sealed container, and then further stirred. Step (3a): The stirred solution is filtered and washed with water to obtain the organic phase. Step (4a): Potassium hydroxide, the organic phase obtained in step (3a), water, diglyme, and methanol are added to a separate container, and the mixture is refluxed. Water is then added to the refluxed reaction mixture to obtain the organic phase. Step (5a): The organic phase obtained in step (4a) is washed with water and then rectified to separate HFE-356mec containing the fluorine-containing diether compound represented by formula (1A).

[0051] In step (1a), examples of containers include stainless steel containers.

[0052] In step (1a), the amount of potassium hydroxide used is preferably 0.1 moles or more and 0.5 moles or less per mole of HFE-356mec.

[0053] In step (1a), the amount of methanol used is preferably 0.6 moles or more and 1.0 mole or less per mole of HFE-356mec.

[0054] In step (2a), the amount of hexafluoropropylene used is preferably 0.6 moles or more and 1.0 mole or less per mole of HFE-356mec.

[0055] In step (2a), the temperature at which hexafluoropropylene is supplied is preferably 0°C or higher and 10°C or lower.

[0056] In step (2a), the pressure at which hexafluoropropylene is supplied is preferably between -0.05 MPaG and 0.30 MPaG.

[0057] In step (2a), the time for supplying hexafluoropropylene is preferably 1 hour or more and 10 hours or less.

[0058] In step (2a), the temperature during stirring is preferably 10°C or higher and 30°C or lower.

[0059] In step (2a), the stirring time is preferably 1 hour or more and 20 hours or less.

[0060] In step (4a), the amount of potassium hydroxide used is preferably 0.1 moles or more and 0.5 moles or less per mole of HFE-356mec.

[0061] In step (4a), the amount of water used is preferably 10 to 30 parts by mass per 100 parts by mass of the organic phase obtained in step (3a).

[0062] In step (4a), the amount of diglyme (diethylene glycol dimethyl ether) used is preferably 10 parts by mass or more and 30 parts by mass or less per 100 parts by mass of the organic phase obtained in step (3a).

[0063] In step (4a), the amount of methanol used is preferably 5 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of the organic phase obtained in step (3a).

[0064] In step (4a), the reflux ratio when refluxing is performed is preferably 0.1 or more and 20 or less.

[0065] In step (4a), the reflux time is preferably 1 hour or more and 10 hours or less.

[0066] In step (5a), the temperature during rectification is preferably 50°C to 80°C.

[0067] In step (5a), the residence time during rectification is preferably 0.5 hours or more and 8 hours or less.

[0068] In step (5a), the pressure used for rectification is preferably between -0.08 MPaG and 0.12 MPaG. The content of the fluorine-containing diether compound represented by formula (1A) in HFE-356mec, which contains the fluorine-containing diether compound represented by formula (1A) separated in step (5a), can be measured, for example, by a gas chromatography-flame ionization detector (GC-FID).

[0069] Manufacturing method B is a manufacturing method that performs the following steps (1b), (2b), (3b), and (4b) in this order. Step (1b): Add sodium hydroxide aqueous solution and methanol to the container and evacuate the gas phase. Step (2b): While stirring the liquid phase of the container, hexafluoropropylene is supplied into the vacuum-sealed container, and then further stirring is performed. Step (3b): Wash the lower layer obtained after stirring with sulfuric acid. Step (4b): HFE-356mec containing a fluorine-containing diether compound represented by formula (1A) is separated by rectification of the lower layer after washing.

[0070] In step (1b), examples of containers include stainless steel containers.

[0071] In step (1b), the amount of aqueous sodium hydroxide solution used is preferably 50 parts by mass or more and 150 parts by mass or less, relative to 100 parts by mass of hexafluoropropylene used in step (2b).

[0072] In step (1b), the amount of methanol used is preferably 20 parts by mass or more and 80 parts by mass or less, relative to 100 parts by mass of hexafluoropropylene used in step (2b).

[0073] In step (2b), the temperature at which hexafluoropropylene is supplied is preferably 0°C or higher and 10°C or lower.

[0074] In step (2b), the pressure at which hexafluoropropylene is supplied is preferably between -0.05 MPaG and 0.30 MPaG.

[0075] In step (2b), the time for supplying hexafluoropropylene is preferably 1 hour or more and 10 hours or less.

[0076] In step (2b), the temperature during stirring is preferably 10°C or higher and 30°C or lower.

[0077] In step (2b), the stirring time is preferably 10 hours or more and 30 hours or less.

[0078] In step (4b), the temperature during rectification is preferably 50°C to 80°C.

[0079] In step (4b), the residence time during rectification is preferably 0.5 hours or more and 8 hours or less.

[0080] In step (4b), the pressure used for rectification is preferably between -0.08 MPaG and 0.12 MPaG.

[0081] The content of the fluorine-containing diether compound represented by formula (1A) in HFE-356mec, which contains the fluorine-containing diether compound represented by formula (1A) separated in step (4b), can be measured, for example, by a gas chromatography-flame ionization detector (GC-FID).

[0082] The compositions of this disclosure contain a fluorine-containing diether compound represented by formula (1) above and a fluorine-containing ether compound represented by formula (2) below. [ka]

[0083] In formula (2), R1 represents a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms.

[0084] In formula (2), R2 is a methyl group, an ethyl group, -CH2CF3, or -CH2(C2F4) n This indicates H.

[0085] In equation (2), n represents an integer between 1 and 10, inclusive.

[0086] In equation (2), it is preferable that n is an integer between 1 and 5, inclusive.

[0087] In formula (2), R2 is preferably a methyl group, an ethyl group, or -CH2CF3.

[0088] In formula (2), it is preferable that R1 is -CF3 and R2 is a methyl group.

[0089] In the compositions of this disclosure, the fluorine-containing ether compound represented by formula (2) is preferably 1,1,2,3,3,3-hexafluoropropyl methyl ether (HFE-356mec).

[0090] In the composition of this disclosure, the content of the fluorine-containing diether compound represented by formula (1) is, with respect to the total amount of the fluorine-containing diether compound represented by formula (1) and the fluorine-containing ether compound represented by formula (2), Preferably 0.1 ppm by mass or more and 20% by mass or less. More preferably 0.2 ppm by mass or more and 5% by mass or less, More preferably 0.4 ppm by mass or more and 1% by mass or less, More preferably 0.6 ppm by mass or more and 0.5% by mass or less, More preferably, 0.8 ppm by mass or more and 0.1% by mass or less. Particularly preferred is 0.9 ppm by mass or more and 0.08% by mass or less. Most preferably 1 ppm by mass or more and 0.06% by mass or less, That is the case.

[0091] In the compositions of this disclosure, the lower limit of the content of the fluorine-containing diether compound represented by formula (1) is, with respect to the total amount of the fluorine-containing diether compound represented by formula (1) and the fluorine-containing ether compound represented by formula (2), The concentration is typically 0.1 ppm by mass, preferably 0.2 ppm by mass, more preferably 0.4 ppm by mass, even more preferably 0.6 ppm by mass, still more preferably 0.8 ppm by mass, still more preferably 0.9 ppm by mass, and particularly preferably 1 ppm by mass.

[0092] In the compositions of this disclosure, the upper limit of the content of the fluorine-containing diether compound represented by formula (1) is, with respect to the total amount of the fluorine-containing diether compound represented by formula (1) and the fluorine-containing ether compound represented by formula (2), Typically, it is 20% by mass, preferably 5% by mass, more preferably 1% by mass, even more preferably 0.5% by mass, still more preferably 0.1% by mass, even more preferably 0.08% by mass, and particularly preferably 0.06% by mass.

[0093] In the compositions of this disclosure, the content of the fluorine-containing diether compound represented by formula (1) can be measured, for example, by a gas chromatography-flame ionization detector (GC-FID).

[0094] In the composition of this disclosure, the sum of the content of the fluorine-containing diether compound represented by formula (1) and the content of the fluorine-containing ether compound represented by formula (2) is usually 95% by mass or more, preferably 97.5% by mass or more, more preferably 99% by mass or more, even more preferably 99.5% by mass or more, and still more preferably 99.9% by mass or more, based on the entire composition.

[0095] It is particularly preferable that the compositions of this disclosure consist only of a fluorine-containing diether compound represented by formula (1) and a fluorine-containing ether compound represented by formula (2). However, in this case, the inclusion of unavoidable impurities is permissible. Such unavoidable impurities include, for example, compounds other than the fluorine-containing diether compound represented by formula (1) and the fluorine-containing ether compound represented by formula (2) that may be produced in the manufacturing process of the compositions of this disclosure.

[0096] The compositions disclosed herein can be suitably used in a wide range of applications, such as cleaning agents, solvents, and heat transfer fluids. Such cleaning agents, solvents, and heat transfer fluids maintain their quality over a long period of time because the generation of hydrogen fluoride is suppressed and degradation is reduced.

[0097] Although embodiments have been described above, it should be understood that various modifications to the form and details are possible without departing from the spirit and scope of the claims. [Examples]

[0098] Embodiments of this disclosure will be described in more detail based on the following examples. However, this disclosure is not limited to these embodiments.

[0099] The apparatus used in the examples and comparative examples is as follows:

[0100] <Gas Chromatography-Mass Spectrometry (GC-MS)> GC-MS measurements were performed using Agilent Technologies, Inc.'s 7890A and 5975C. The 7890A is the model number for the GC section of the GC-MS, and the 5975C is the model number for the MS section.

[0101] <Gas chromatography-flame ionization detector (GC-FID)> Measurements using GC-FID were performed using a GC-2030 manufactured by Shimadzu Corporation.

[0102] <Fluoride ion meter> The fluoride ion concentration was measured using a benchtop water quality analyzer manufactured by Horiba, Ltd.

[0103] (Example 1) In a 150cc stainless steel autoclave equipped with stirring blades, 2.48g (44 mmol) of potassium hydroxide, 6.77g (211 mmol) of methanol, and 44.94g (247 mmol) of HFE-356mec were added, and the gas phase was evacuated while cooling to -20°C. Then, while stirring the liquid phase, 30.71g (205 mmol) of hexafluoropropylene was blown into the evacuated gas phase over 1 hour at a temperature of 5°C and a pressure of 0.20 MPaG. The mixture was then stirred at 20°C for 4 hours. The reaction mixture obtained after stirring was filtered and washed with water, and 68.3g of the organic layer was separated. Next, 2.48 g (44 mmol) of potassium hydroxide, 68.3 g of the separated organic layer, 10 g of water, and 10 g (75 mmol) of diglyme (diethylene glycol dimethyl ether) were added to a 200 cc three-necked flask equipped with a stirring bar and reflux tubing. Then, 6.77 g (211 mmol) of methanol was added dropwise. The mixture was refluxed for 5 hours. The temperature of the reaction mixture during reflux was 55°C, and the temperature of the cooling liquid flowing through the reflux tubing was 5°C. After 5 hours of reflux, 50 g of water was added to the reaction mixture and liquid-liquid was separated. The resulting organic layer (lower layer) was washed twice with water and rectified under atmospheric pressure (0 MPaG) at a temperature of 70°C in the still for 1 hour to recover components with a boiling point of around 54°C. GC-MS analysis of the recovered product confirmed that 38.2 g of HFE-356mec containing the fluorine-containing diether compound shown in formula (1A) below (hereinafter also referred to as "fluorine-containing diether compound A") was obtained. GC-FID analysis confirmed that the content of fluorine-containing diether compound A relative to the total amount of fluorine-containing diether compound A and HFE-356mec was 12% by mass. Figure 1 shows the mass spectrum obtained from GC-MS of fluorine-containing diether compound A. [ka] GC-MS(EI) m / z:194, 175, 142, 132, 125, 110, 91, 82, 75, 69

[0104] (Example 2) In a 3L stainless steel autoclave equipped with stirring blades, 690g of 7% sodium hydroxide aqueous solution and 272g (8.5mol) of methanol were added, and the gas phase was evacuated while cooling to -5°C. Then, while stirring the liquid phase, 602g (4.0mol) of hexafluoropropylene was blown into the evacuated gas phase over 5 hours under conditions of a liquid phase temperature of 5°C and a pressure of 0.10 MPaG. The mixture was then stirred at 20°C for 20 hours. The resulting lower layer was washed with 10% sulfuric acid, and the washed lower layer was rectified at atmospheric pressure (0 MPaG) at a still temperature of 70°C over 6 hours to recover components with a boiling point of around 54°C. GC-MS analysis confirmed that 351g (73% yield) of HFE-356mec, containing fluorine-containing diether compound A, was obtained. GC-FID measurement confirmed that the content of fluorine-containing diether compound A relative to the total amount of HFE-356mec was 32 ppm by mass (GCArea%). "GCArea%" refers to the occupancy rate when the total peak area on the gas chromatograph is set to 100%.

[0105] (Example 3) 252 g of 8% potassium hydroxide aqueous solution and 83 g (2.5 mol) of methanol were added to a 1 L stainless steel autoclave equipped with stirring blades, and the gas phase was evacuated while cooling to -10°C. Then, while stirring the liquid phase, 233 g (1.5 mol) of hexafluoropropylene was blown into the evacuated gas phase over 2 hours under conditions of a liquid phase temperature of 5°C and a pressure of 0.10 MPaG. The mixture was then stirred at 20°C for 20 hours to obtain a two-layer reaction solution. 81 g of potassium hydroxide was added to the obtained reaction solution, and the mixture was stirred at 40°C for 25 hours. After stirring, the lower layer was washed with 10% sulfuric acid and water, and the washed lower layer was rectified at atmospheric pressure (0 MPaG) at a temperature of 70°C in the still for 3 hours to recover components with a boiling point of around 54°C. GC-MS analysis of the recovered product confirmed that 179 g (65.5% yield) of HFE-356mec containing fluorine-containing diether compound A was obtained. GC-FID analysis confirmed that the content of fluorine-containing diether compound A relative to the total amount of HFE-356mec was 3 ppm by mass (GC Area%).

[0106] (Comparative Example 1) 1367 g of 10% potassium hydroxide methanol solution (2.4 mol potassium hydroxide, 38.4 mol methanol) was added to a 5 L three-necked glass flask equipped with a stirring blade and reflux tubing. 1924 g (12.8 mol) of hexafluoropropylene was bubbled over 10 hours while stirring the liquid phase. During bubbling, the temperature of the liquid phase was maintained at 30°C, and the gas phase was opened to the atmosphere via the reflux tubing. After bubbling was complete, the reaction mixture was poured into ice water over 30 minutes to separate the lower layer. The obtained lower layer was washed twice with ice water and dried with phosphorus pentoxide. Then, under atmospheric pressure (0 MPaG), rectification was performed at a temperature of 70°C in the still for 10 hours to recover the components with a boiling point of around 54°C. GC-FID measurement confirmed that the content of fluorine-containing diether compound A relative to the total amount of HFE-356mec was below the detection limit [less than 0.1 ppm by mass (GCArea%)].

[0107] (Test Example 1) 28 g (20 cc) of HFE-356mec containing 96 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. The valve was then quickly closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 70 / 30. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After standing at 120°C for 24 months, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0108] (Test Example 2) 28 g (20 cc) of HFE-356mec containing 96 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. Then, under dry ice cooling, the gas phase was evacuated and the valve was closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 0 / 100. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a constant temperature bath at 120°C for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0109] (Test Example 3) 28 g (20 cc) of HFE-356mec containing 1 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. The valve was then quickly closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 70 / 30. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0110] (Test example 4) 28 g (20 cc) of HFE-356mec containing 1 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. Then, under dry ice cooling, the gas phase was evacuated and the valve was closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 0 / 100. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0111] (Test Example 5) 28 g (20 cc) of HFE-356mec containing 511 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. The valve was then quickly closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 70 / 30. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0112] (Test Example 6) 28 g (20 cc) of HFE-356mec containing 511 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. Then, under dry ice cooling, the gas phase was evacuated and the valve was closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 0 / 100. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a constant temperature bath at 120°C for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0113] (Test Example 7) 28 g (20 cc) of HFE-356mec containing 5 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. The valve was then quickly closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 70 / 30. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0114] (Test Example 8) 28 g (20 cc) of HFE-356mec containing 5 ppm by mass of fluorine-containing diether compound A was added to a 75 cc stainless steel cylinder equipped with a valve. Then, under dry ice cooling, the gas phase was evacuated and the valve was closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 0 / 100. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a constant temperature bath at 120°C for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0115] (Comparative Test Example 1) 28 g (20 cc) of HFE-356mec, containing less than 0.1 ppm by mass (below the detection limit) of fluorine-containing diether compound A, was added to a 75 cc stainless steel cylinder equipped with a valve. The valve was then quickly closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 70 / 30. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After 24 months, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0116] (Comparative Test Example 2) 28 g (20 cc) of HFE-356mec, containing less than 0.1 ppm by mass (below the detection limit) of fluorine-containing diether compound A, was added to a 75 cc stainless steel cylinder equipped with a valve. Then, under dry ice cooling, the gas phase was evacuated and the valve was closed to adjust the molar ratio of air to HFE-356mec (air / HFE-356mec) in the gas phase of the stainless steel cylinder to 0 / 100. After adjustment, the fluoride ion concentration (ppm) was measured using a fluoride ion meter. After measurement, the stainless steel cylinder was left to stand in a 120°C constant temperature bath for 24 months. After 24 months of standing, the fluoride ion concentration (ppm) was measured using a fluoride ion meter.

[0117] The results for each test example and each comparative test example are shown in Table 1.

[0118] In Table 1, "Content of fluorine-containing diether compound A (mass ppm)" refers to the content (mass ppm) of fluorine-containing diether compound A relative to the total amount of fluorine-containing diether compound A and HFE-356mec.

[0119] In Table 1, "Fluoride ion concentration before the start of the test (ppm)" refers to the total concentration (ppm) of the fluoride ion concentration of HFE-356mec and the fluoride ion concentration of fluorine-containing diether compound A immediately after adjusting the molar ratio (air / HFE-356mec).

[0120] In Table 1, "Fluoride ion concentration (ppm) after standing at 120°C for 24 months" refers to the total concentration (ppm) of fluoride ions from HFE-356mec and fluoride ions from fluoride-containing diether compound A after standing at 120°C for 24 months.

[0121] [Table 1] JPEG2026065628000008.jpg255125

[0122] [Discussion of the results in Table 1] As shown in Test Examples 1-8, it was confirmed that the increase in fluoride ion concentration in the solution was suppressed when the content of fluoride-containing diether compound A was 1 ppm by mass or more. The increase in fluoride ion concentration suggests the presence of decomposition of the fluorine compounds constituting the fluorine solvent. This trend was particularly pronounced when air was present in the gas phase (Test Examples 1, 3, 5, 7, and Comparative Test Example 1).

[0123] Specifically, when the content of fluorine-containing diether compound A was less than 0.1 ppm by mass (Comparative Test Example 1), the fluoride ion concentration after standing at 120°C for 24 months was 3.4 ppm. In contrast, when the content of fluorine-containing diether compound A was 1 ppm by mass (Test Example 3), 5 ppm by mass (Test Example 7), 96 ppm by mass (Test Example 1), and 511 ppm by mass (Test Example 5), the fluoride ion concentrations after standing at 120°C for 24 months were 0.7 ppm (Test Example 3), less than 0.1 ppm (Test Example 7), less than 0.1 ppm (Test Example 1), and less than 0.1 ppm (Test Example 5), respectively.

[0124] When the air in the gas phase was removed (Test Examples 2, 4, 6, 8, and Comparative Test Example 2), the fluoride ion concentration after standing at 120°C for 24 months was 0.3 ppm only when the content of fluorine-containing diether compound A was less than 0.1 ppm by mass (Comparative Test Example 2), suggesting that there was a slight decomposition of the fluorine compounds constituting the fluorine solvent. When the air in the gas phase was removed and the content of fluorine-containing diether compound A was 1 ppm by mass or more (Test Examples 2, 4, 6, and 8), the fluoride ion concentration after standing at 120°C for 24 months remained unchanged from the fluoride ion concentration before the start of the test, and was less than 0.1 ppm.

[0125] It is generally known that fluorine-containing ether compounds begin to decompose when a hydrogen atom is radically removed from the α-carbon of the ether oxygen. Furthermore, this phenomenon is known to be accelerated in the presence of oxygen molecules. It is unclear whether the significant increase in fluorine ion concentration observed when fluorine-containing diether compound A was less than 0.1 ppm by mass was due to decomposition by this mechanism. However, in comparative test example 1, the fluorine ion concentration increased more significantly in the presence of air, suggesting that decomposition by this mechanism occurred in comparative test example 1, and that fluorine-containing diether compound A may have an effect in suppressing the decomposition of fluorine compounds by this mechanism.

Claims

1. The following formula (1): 【Chemistry 1】 (In formula (1), R １ This represents a fluorine atom or a perfluoroalkyl group having 1 to 10 carbon atoms. R ２ These are the same or different methyl group, ethyl group, -CH ２ CF ３ , or -CH ２ (C ２ F ４ ) ｎ Show H, n represents an integer between 1 and 10 (inclusive). A fluorine-containing diether compound represented by the following:

2. In the formula (1), R １ is a fluorine atom or -CF ３ and R ２ are the same or different and are a methyl group or -CH ２ CF ３ The fluorine-containing diether compound according to claim 1.

3. In the above formula (1), R １ ga-CF ３ And R ２ The fluorine-containing diether compound according to claim 1, wherein the group is a methyl group.

4. A fluorine-containing diether compound according to any one of claims 1 to 3, Formula (2) below: 【Chemistry 2】 (In formula (2), R １ and R ２ (This is the same as above.) A fluorine-containing ether compound represented by, A composition containing the following:

5. The composition according to claim 4, wherein the content of the fluorine-containing diether compound according to any one of claims 1 to 3 is 0.1 ppm by mass or more and 20% by mass or less, relative to the total amount of the fluorine-containing diether compound and the fluorine-containing ether compound represented by formula (2).

6. The composition according to claim 5, wherein the fluorine-containing ether compound represented by formula (2) is 1,1,2,3,3,3-hexafluoropropyl methyl ether (HFE-356mec).

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