Method for reducing the concentration of hydrofluoroether olefins

Abstract

Provided is a method capable of effectively reducing the concentration of a hydrofluoroether alkene (HFEO) in a mixture containing a hydrofluoroether (HFE) and the HFEO. In the method for reducing the concentration of the HFEO of the present invention, the HFE is a compound (A) represented by the following formula (1), the HFEO is a compound (B) represented by the following formula (2), and the compound (B) in the aforementioned mixture is reacted with any one of an alcohol, chlorine gas, and hydrogen gas, which is a compound (C).R 2 -O-R 1 -O-R 3 (1) R 2 -O-R 1 -O-R 4 (2) In formulas (1) and (2), R 1 is an alkylene group having 1 to 4 carbon atoms, R 2 and R 3 are each independently a fluoroalkyl group having 2 to 4 carbon atoms, and R 4 is a fluoroalkenyl group having 2 to 4 carbon atoms.

Description

Technical Field

[0001] This invention relates to a method for reducing the concentration of HFEO in a mixture of hydrofluoroether (HFE) and hydrofluoroether olefin (HFEO). Background Technology

[0002] Heat transfer media are used in various heat transfer methods, such as temperature control of wafers in semiconductor manufacturing, cooling and heating of semiconductor components and electronic parts, server cooling, heat pumps, heat pipes, and temperature control of thermostatic baths.

[0003] Perfluorocarbons (PFCs) have been widely used as heat transfer media in the past due to their non-flammability and low ozone depletion potential (ODP). However, PFCs have the problem of high global warming potential (GWP) and significant environmental impact due to the greenhouse effect.

[0004] Therefore, HFE, which has low ODP and low GWP and has a less environmental impact, is being studied as an alternative heat transfer medium to PFC (see, for example, Patent Document 1). HFE is generally known to be synthesized, for example, by the addition reaction of fluoroolefins with diols in the presence of a base catalyst.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Publication No. 2007-524737 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] In the aforementioned synthesis method, not only the desired HFE is synthesized, but also HFEO, generated by the removal of hydrogen fluoride from the HFE molecule, is produced. HFEO sometimes thermally decomposes at high temperatures, such as above 90°C, to form acids. When HFE is used as a heat transfer medium, if the byproduct HFEO is present in large quantities as an impurity, there is a concern that it may cause corrosion of the flow path of the heat transfer medium and the surrounding components of the device.

[0010] From the above perspective, when using HFE as a heat transfer medium, it is desirable to keep the concentration of HFEO, as an impurity, as low as possible. However, HFE and the byproduct HFEO have similar boiling points, making it difficult to separate them using conventional methods such as distillation.

[0011] Therefore, methods are sought to effectively reduce the concentration of HFEO in mixtures containing HFE and HFEO, other than through distillation purification.

[0012] The present invention was made in view of the following situation, and its object is to provide a method that can effectively reduce the concentration of HFEO in a mixture containing HFE and HFEO.

[0013] Solution for solving the problem

[0014] This invention is based on the discovery that HFEO can be converted into other compounds without affecting coexisting HFE, thereby reducing the concentration of HFEO.

[0015] The present invention provides the following methods.

[0016] [1] A method for reducing the concentration of hydrofluoroether olefins, which is a method for reducing the concentration of hydrofluoroether olefins in a mixture containing hydrofluoroether and hydrofluoroether olefins, wherein the hydrofluoroether is compound (A) as shown in formula (1) below, and the hydrofluoroether olefin is compound (B) as shown in formula (2) below, wherein compound (B) in the mixture is reacted with any compound (C) among alcohol, chlorine and hydrogen.

[0017] R 2 -OR 1 -OR 3 (1)

[0018] R 2 -OR 1 -OR 4 (2)

[0019] In equations (1) and (2), R 1 R is an alkylene group having 1 to 4 carbon atoms. 2 and R 3 Each is independently a fluoroalkyl group having 2 to 4 carbon atoms, R 4 It is a fluoroolefin with 2 to 4 carbon atoms.

[0020] [2] According to the method for reducing the concentration of hydrofluoroether olefins described in [1], the difference between the boiling points of compound (A) and compound (B) is less than 10°C.

[0021] [3] According to the method for reducing the concentration of hydrofluoroether olefins as described in [1] or [2], wherein compound (C) is an alcohol or chlorine, and the boiling point of compound (D) obtained by reacting compound (B) with alcohol or chlorine is more than 15°C different from the boiling point of compound (A).

[0022] [4] According to the method for reducing the concentration of hydrofluoroether olefins described in [3], the crude product obtained by reacting the aforementioned mixture with compound (C) is distilled to separate and remove compound (D).

[0023] [5] The method for reducing the concentration of hydrofluoroether olefins according to [4], wherein the crude product or the composition obtained by distilling the crude product contains a fluorinated carboxylic acid compound, and the method for reducing the concentration of hydrofluoroether olefins includes a step of mixing the crude product or the composition obtained by distilling the crude product with an alkaline aqueous solution to remove the fluorinated carboxylic acid compound.

[0024] [6] A method for reducing the concentration of hydrofluoroether olefins according to any one of [1] to [5], wherein the alcohol is a primary alcohol.

[0025] [7] The method for reducing the concentration of hydrofluoroether olefins according to [6], wherein the primary alcohol is methanol, ethanol or 1-propanol.

[0026] [8] The method for reducing the concentration of hydrofluoroether olefins according to [1] or [2], wherein compound (C) is hydrogen.

[0027] [9] A method for reducing the concentration of hydrofluoroether olefins according to any one of [1] to [8], wherein compound (A) is 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane and compound (B) is 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene.

[0028]

[10] A hydrofluoroether-containing composition with reduced concentration of hydrofluoroether olefin, obtained by any one of the methods described in [1] to [9] for reducing the concentration of hydrofluoroether olefin.

[0029]

[11] A heat medium, which is the hydrofluoroether-containing composition described in

[10] .

[0030]

[12] The heat medium according to

[11] is used for cooling or heating of components in a semiconductor manufacturing apparatus.

[0031] The effects of the invention

[0032] According to the present invention, the concentration of HFEO in a mixture containing HFE and HFEO can be effectively reduced. Detailed Implementation

[0033] The method for reducing the concentration of HFO in the embodiment of the present invention (hereinafter also referred to as this embodiment) is a method for reducing the concentration of HFEO in a mixture containing HFE and HFEO, characterized in that HFE is compound (A) represented by the following formula (1), HFEO is compound (B) represented by the following formula (2), and compound (B) in the aforementioned mixture is reacted with any compound (C) among alcohol, chlorine and hydrogen.

[0034] R 2 -OR 1 -OR 3 (1)

[0035] R 2 -OR 1 -OR 4 (2)

[0036] In equations (1) and (2), R 1 R is an alkylene group having 1 to 4 carbon atoms. 2 and R 3 Each is independently a fluoroalkyl group having 2 to 4 carbon atoms, R 4 It is a fluoroolefin with 2 to 4 carbon atoms.

[0037] According to this embodiment, as a compound that reacts with a mixture containing HFE and HFEO, the use of alcohol, chlorine, or hydrogen does not affect HFE, and HFEO can be effectively converted into other compounds, thereby reducing the concentration of HFEO.

[0038] In this embodiment, HFE is compound (A) as shown in formula (1).

[0039] R 2 -OR 1 -OR 3 (1)

[0040] R 1 It is an alkylene group having 1 to 4 carbon atoms, preferably an alkylene group having 2 to 4 carbon atoms, more preferably an alkylene group having 2 to 3 carbon atoms. The carbon chain can be straight or branched, preferably straight.

[0041] R 2 and R 3 Each fluoroalkyl group is independently composed of 2 to 4 carbon atoms, and they may be the same or different. From the viewpoint of fluidity and ease of manufacture as a heat transfer medium, the number of carbon atoms is 2 to 4, preferably 3 or 4. The carbon chain of the fluoroalkyl group may be linear or branched, preferably linear.

[0042] R 2 and R 3 The fluoroalkyl group preferably has one hydrogen atom, which can be bonded to any carbon atom, preferably to a carbon atom adjacent to R. 2 Or R 3 The oxygen atom (ether oxygen atom) is bonded to the hydrogen atom (β hydrogen) of the second carbon atom.

[0043] In this embodiment, HFEO is compound (B) as shown in formula (2).

[0044] R2 -OR 1 -OR 4 (2)

[0045] R in equation (2) 1 and R 2 R in equation (1) 1 and R 2 same.

[0046] R 4 The fluoroolefin is composed of 2 to 4 carbon atoms. From the viewpoint of fluidity and ease of manufacture as a heat transfer medium, the number of carbon atoms is 2 to 4, preferably 3 or 4. The carbon chain of the fluoroolefin can be linear or branched, preferably linear.

[0047] From the perspective of fluidity and ease of manufacture as a heat transfer medium, R 4 The fluoroolefin is preferably formed by bonding any carbon atom that constitutes a carbon-carbon double bond to an adjacent oxygen atom. 4 The fluoroolefin can have hydrogen atoms, preferably perfluoroolefin.

[0048] The mixture containing compound (A) and compound (B) may contain other components as impurities besides compound (A) and compound (B), but from the viewpoint of effectively reducing the concentration of HFEO, other components are preferably as few as possible. From the viewpoint of purification efficiency, the content of other components in the mixture is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 0% by mass.

[0049] The method for reducing the concentration of HFEO in this embodiment (hereinafter, sometimes referred to as the method of this embodiment) is particularly effective when the boiling points of compound (A) and compound (B) are similar when the difference between their boiling points is less than 10°C, making them particularly effective in situations where conventional separation methods such as distillation are difficult.

[0050] When the boiling points of compounds (A) and (B) are similar, it is difficult to separate compounds (A) and (B) by distillation. However, according to the method of this embodiment, by converting compound (B) as HFEO into other compounds, the concentration of compound (B) in the mixture of compounds (A) and (B) can be reduced.

[0051] It should be noted that the boiling point mentioned in this instruction manual is the boiling point under a pressure of 0.1 MPa (1 atm).

[0052] As a specific example of the combination of compound (A) and compound (B), 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane (CF3CHFCF2OCH2CH2OCF2CHFCF3; HFE-77-12) and 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene can be cited. Combinations such as (CF3CF=CFOCH2CH2OCF2CHFCF3); combinations of 1,1,2,2-tetrafluoro-1-[2-(1,1,2,2-tetrafluoroethoxy)ethoxy]ethane (CHF2CF2OCH2CH2OCF2CHF2) and 1,2-trifluoro-1-[2-(1,1,2,2-tetrafluoroethoxy)ethoxy]-1-ethane (CF2=CFOCH2CH2OCF2CHF2). Among these, the method of this embodiment is more effective in the case of HFE-77-12 and 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene (CF3CF=CFOCH2CH2OCF2CHFCF3; hereinafter referred to as the HF-de-fluorinated form) having a structure in which hydrogen fluoride is removed from HFE-77-12 (both with a boiling point of 164°C).

[0053] Compound (C) is an alcohol, chlorine, or hydrogen. By reacting compound (C) with the carbon-carbon double bond of compound (B), compound (B) is converted into compound (D).

[0054] When compound (C) is an alcohol, compound (B) is converted into compound (D) in which a fluorine atom bonded to one carbon atom with a carbon-carbon double bond is replaced by an alkoxy group.

[0055] In the reaction that converts compound (B) into the HFEO of such an alkoxy-substituted compound, namely compound (D), from the viewpoint of preventing the removal reaction of hydrogen fluoride from compound (A) in the mixture, the alcohol used as compound (C) is preferably a primary alcohol. Among these, from the viewpoints of versatility and reactivity, methanol, ethanol, or 1-propanol are preferred, with methanol being more preferred.

[0056] For example, when compound (A) is HFE-77-12, compound (B) is the deHF derivative, and compound (C) is methanol, compound (D) is 1,3,3,3-hexafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-2-methoxy-1-propene (CF3C(OCH3)=CFOCH2CH2OCF2CHFCF3) as the methoxy-substituted derivative of the deHF derivative.

[0057] To facilitate the distillation separation of the alkoxy-substituted compound (D) to obtain high-purity compound (A), the difference between the boiling point of compound (D) and the boiling point of compound (A) is preferably 15°C or more, more preferably 20°C or more, and even more preferably 25°C or more. Both the boiling points of the alkoxy-substituted compound (D) and compound (A) can be relatively high, but generally the boiling point of compound (D) is higher than that of compound (A).

[0058] By giving the alkoxy-substituted compound (D) and compound (A) such a boiling point difference, compound (D) can be separated and removed by distillation of the crude product obtained by reacting a mixture containing compound (A) and compound (B) with compound (C). As a purified composition by distillation, compound (A) of high purity can be obtained.

[0059] The purified composition is obtained as a high-purity compound (A) with a content of compound (B) preferably less than 0.1 mol%, more preferably less than 0.05 mol%, and even more preferably less than 0.03 mol%.

[0060] When compound (C) is an alcohol, the amount of alcohol used relative to compound (B) is preferably 1.0 to 20.0 molar equivalents, more preferably 2.0 to 18.0 molar equivalents, and even more preferably 3.0 to 15.0 molar equivalents.

[0061] From the viewpoint of efficient reaction, the reaction is preferably carried out at -20°C or above, more preferably at -10°C or above, and even more preferably at 0°C or above. Furthermore, from the viewpoint of suppressing the formation of byproducts, the reaction is preferably carried out at 80°C or below, more preferably at 70°C or below, and even more preferably at 60°C or below. The reaction can be carried out under normal pressure, preferably in the presence of a base catalyst.

[0062] Examples of alkaline catalysts include potassium hydroxide, sodium hydroxide, potassium bicarbonate, sodium bicarbonate, potassium carbonate, sodium carbonate, and triethylamine. From the viewpoint of efficient reaction, potassium hydroxide is preferred. The amount of alkaline catalyst used relative to compound (B) is preferably 1.0 to 10.0 molar equivalents, more preferably 2.0 to 8.0 molar equivalents, and even more preferably 3.0 to 5.0 molar equivalents. Furthermore, from the viewpoint of uniform mixing in the reaction system, the alkaline catalyst is preferably added in the form of an aqueous solution.

[0063] When using an aqueous solution of potassium hydroxide, the concentration of the aqueous solution is preferably 10-70% by mass, more preferably 15-60% by mass, and even more preferably 20-50% by mass.

[0064] When compound (C) is chlorine gas, compound (B) is converted into compound (D) by adding chlorine atoms to two carbon atoms with carbon-carbon double bonds.

[0065] For example, when compound (A) is HFE-77-12 and compound (B) is the HF-free form, compound (D) is 1,1,1,2,3-pentafluoro-2,3-dichloro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane (CF3CFClCFClOCH2CH2OCF2CHFCF3).

[0066] For the chloroaddition HFE, i.e., compound (D), which is a product of compound (B), to facilitate distillation separation and obtain high-purity compound (A), the difference between the boiling point of compound (D) and the boiling point of compound (A) is preferably 15°C or more, more preferably 20°C or more, and even more preferably 25°C or more. The boiling points of both the chloroaddition compound (D) and compound (A) can be relatively high, but generally, the boiling point of compound (D) is higher than that of compound (A).

[0067] By creating a boiling point difference between the chlorinated adduct compound (D) and compound (A), compound (D) can be separated and removed by distillation of the crude product obtained by reacting compound (C) with a mixture containing compound (A) and compound (B). As a purified composition by distillation, compound (A) of high purity can be obtained.

[0068] The purified composition is obtained as a high-purity compound (A) with a content of compound (B) preferably less than 0.1 mol%, more preferably less than 0.05 mol%, and even more preferably less than 0.03 mol%.

[0069] When compound (C) is chlorine, the amount of chlorine used relative to compound (B) is preferably 1.0 to 2.0 molar equivalents, more preferably 1.05 to 1.75 molar equivalents, and even more preferably 1.1 to 1.5 molar equivalents.

[0070] From the viewpoint of efficient reaction, the reaction is preferably carried out at -20°C or above, more preferably at -10°C or above, and even more preferably at 0°C or above. Furthermore, from the viewpoint of suppressing the formation of byproducts, the reaction is preferably carried out at 80°C or below, more preferably at 70°C or below, and even more preferably at 60°C or below. The reaction can be carried out under normal pressure, and from the viewpoint of suppressing the formation of byproducts, it is preferably carried out in the dark.

[0071] When compound (C) is hydrogen gas, compound (B) is converted into compound (D) by adding hydrogen atoms to two carbon atoms that have carbon-carbon double bonds.

[0072] For example, when compound (A) is HFE-77-12 and compound (B) is a de-HF derivative, compound (D) is 1,1,1,2,3-pentafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane (CF3CHFCHFOCH2CH2OCF2CHFCF3).

[0073] For HFE, i.e., compound (D), which is a hydrogen adduct converted from compound (B), the boiling point is usually similar to that of compound (A), making it difficult to separate from compound (A) by distillation. However, even when used as a heat medium in the presence of compound (A), it will not corrode the flow path of the heat medium and its surrounding device components due to acid formation, as is the case with compound (B).

[0074] When compound (C) is hydrogen, from a safety point of view, the amount of hydrogen used relative to compound (B) is preferably 1.0 to 100 molar equivalents, more preferably 1.0 to 50 molar equivalents, and even more preferably 1.0 to 10 molar equivalents.

[0075] From the viewpoint of efficient reaction, the reaction is preferably carried out at -20°C or above, more preferably at -10°C or above, and even more preferably at 0°C or above. Furthermore, from the viewpoint of suppressing the formation of byproducts, the reaction is preferably carried out at 80°C or below, more preferably at 70°C or below, and even more preferably at 60°C or below. From the viewpoint of facilitating the introduction of hydrogen into the liquid phase, the reaction is preferably carried out under pressure, but it can also be carried out under atmospheric pressure. Additionally, the reaction is preferably carried out in the presence of a hydrogenation catalyst.

[0076] Examples of hydrogenation catalysts include metal catalysts such as iridium, nickel, palladium, platinum, rhodium, and ruthenium. From the viewpoint of catalytic effect and cost, the amount of hydrogenation catalyst relative to the total amount of compound (A) and compound (B) is preferably 0.001 to 50% by mass, more preferably 0.005 to 30% by mass, even more preferably 0.01 to 10% by mass, and particularly preferably 0.01 to 1% by mass.

[0077] From the perspective of ease of acquisition, the preferred hydrogenation catalyst is palladium-activated carbon (containing Pd10 by mass%).

[0078] By distilling and purifying the crude product obtained by reacting a mixture containing compound (A) and compound (B) with hydrogen, a mixture containing compound (A) and compound (D) but without compound (B) can be obtained.

[0079] As compound (C), alcohol is preferred from the viewpoint of safety and ease of handling compared to chlorine or hydrogen, which are treated as gases.

[0080] Furthermore, the reaction of hydrogen is preferably carried out in the presence of a metal catalyst, especially a noble metal catalyst. Moreover, given the difficulty in distilling and separating the resulting hydrogen adduct from compound (A), alcohols or chlorine are preferred as compound (C) in order to obtain high-purity compound (A). Additionally, alcohols are more preferred from a reactivity point of view than chlorine, which sometimes also reacts with compound (A).

[0081] It should be noted that the crude product obtained by reacting a mixture containing compounds (A) and (B) with compound (C), and the composition obtained by distillation purification of the aforementioned crude product (hereinafter also referred to as crude product, etc.), sometimes contain fluorinated carboxylic acid compounds as impurities. In this case, by mixing the crude product, etc. with an alkaline aqueous solution, it is easy to obtain compound (A) with high purity after the removal of fluorinated carboxylic acid compounds.

[0082] There are no particular limitations on alkaline solutions; examples include aqueous solutions of potassium carbonate, sodium carbonate, potassium bicarbonate, sodium bicarbonate, potassium hydroxide, and sodium hydroxide.

[0083] From the viewpoint of improving the removal efficiency of fluorinated carboxylic acid compounds, the temperature at which the crude product is mixed with the alkaline aqueous solution is preferably 40°C or higher, more preferably 60°C or higher, more preferably 80°C or higher, and even more preferably 100°C or higher. Furthermore, from the viewpoint of inhibiting the decomposition of compound (A), the temperature is preferably 180°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower. The mixing time is preferably 1 to 10 hours.

[0084] From the viewpoint of improving the removal efficiency of fluorinated carboxylic acid compounds, it is preferable to mix the crude product and the alkaline aqueous solution while stirring.

[0085] When the crude product is mixed with an alkaline aqueous solution, the organic layer of the resulting mixture can be distilled to separate and remove compound (D), thereby obtaining a high-purity compound (A) as a distillation purified product.

[0086] Examples of synthetic methods that include a mixture of compound (A) and compound (B) include a method in which a fluoroolefin is added to a diol in the presence of a base catalyst such as potassium carbonate, followed by a desorption reaction of hydrogen fluoride in the presence of a strong base such as an alkali metal alkoxide.

[0087] By using the HFEO concentration reduction method of this embodiment described above, an HFE-containing composition with compound (A) as the main component and a reduced concentration of compound (B) can be obtained. Such an HFE-containing composition is suitable for a wide range of applications, including cleaning agents, solvents, foaming agents, aerosols, heat pipes, working media for binary power generation such as heat recovery in factories, preservation solutions for electronic components, gross leak tests for electronic components, thermal shock tests, liquid aging tests, and voltage withstand tests. It is particularly suitable for heat media. For example, it can be used for temperature control of wafers in semiconductor manufacturing, cooling and heating of semiconductor components and electronic parts, server cooling, heat pumps, heat pipes, and thermostatic baths. Compound (A) has good insulating properties, making it suitable for cooling or heating components in semiconductor manufacturing equipment, and particularly for handling the harsh conditions of high electric fields and high temperatures in semiconductor manufacturing processes such as dry etching using plasma.

[0088] Example

[0089] The present invention will be specifically described below based on embodiments, but the present invention is not limited to the following embodiments.

[0090] The reaction products were identified by proton nuclear magnetic resonance (NMR). 1 ¹H NMR spectroscopy, fluorine-19 NMR ( 19 The spectroscopy was performed using F NMR and gas chromatography-mass spectrometry (GC-MS, using a column: "DB-1301", 60m in length, 250μm in inner diameter, 1μm in thickness; manufactured by Agilent Technologies, Inc.).

[0091] [Synthesis example 1]

[0092] In a 2.1-liter stainless steel autoclave equipped with a stirrer, add 223g of potassium carbonate (manufactured by Junki Chemical Co., Ltd.), 200g of ethylene glycol (manufactured by Junki Chemical Co., Ltd.), and 400g of anhydrous acetonitrile (manufactured by Fujifilm and Kazumitsu Chemical Co., Ltd.), and maintain the autoclave at 20°C under a sealed environment. Stir the contents of the autoclave, and add 966g of hexafluoropropylene (manufactured by AGC Co., Ltd.) in a gaseous state over 6 hours. After maintaining the reaction at 20°C for 1 hour, filter and recover the crude reaction liquid from the autoclave.

[0093] The recovered crude reaction liquid was subjected to phase separation and washing with water. After drying with molecular sieve 3A (manufactured by Fujifilm and Koichi Chemical Co., Ltd.), it was purified by distillation to obtain a mixture of HFE-77-12 and the de-HF product (95.3 mol% HFE-77-12, 4.7 mol% byproduct of hydrogen fluoride removal from HFE-77-12).

[0094] [Example 1] Reaction with alcohols

[0095] 200 g of the mixture obtained in Synthesis Example 1, 10 g of methanol (manufactured by Pure Chemical Industries, Ltd.), and 10 g of a 48% by mass potassium hydroxide aqueous solution (manufactured by Kanto Chemical Co., Ltd.) were added to a stainless steel autoclave (internal volume 2.1 L) equipped with a stirrer. The mixture was stirred at 20°C under a closed system. After reacting for 3 hours, the crude reaction liquid in the autoclave was subjected to phase separation, washed with distilled water, and dried with molecular sieve 3A (manufactured by Fujifilm and Kojun Chemical Co., Ltd.; the same applies below) to obtain the crude product (HFE-77-12 95.3 mol%, deHF-free form 0.01 mol%, methoxy-substituted product 4.6 mol%, fluorinated carboxylic acid 0.05 mol%, other components 0.04 mol%).

[0096] Next, the crude product was distilled to obtain the purified product (HFE-77-12 99.99 mol%, HF-free body 0.01 mol%).

[0097] [Example 2] Reaction with chlorine gas

[0098] 200 g of the mixture obtained in Synthesis Example 1 and 2.3 g of chlorine gas (manufactured by Toa Synthetic Co., Ltd.) were added to a stainless steel autoclave (internal volume 2.1 L) equipped with a stirrer, and stirred at 20 °C under a closed system. After reacting for 1 hour, the crude reaction liquid in the autoclave was recovered, neutralized with potassium bicarbonate aqueous solution and phase separated, and dried with molecular sieve 3A to obtain the crude product (HFE-77-12 95.1 mol%, deHF derivative 0.01 mol%, chloroadditrile derivative 4.6 mol%, other components 0.29 mol%).

[0099] Next, the crude product was distilled to obtain the purified product (HFE-77-12 99.99 mol%, HF-free body 0.01 mol%).

[0100] [Example 3] Reaction with hydrogen

[0101] 200 g of the mixture obtained in Synthesis Example 1, 150 g of ethyl acetate (manufactured by Pure Chemical Industries, Ltd.), and 0.3 g of palladium-activated carbon (containing Pd10 by mass%) (manufactured by Fujifilm and Kojun Chemical Co., Ltd.) were added to a stainless steel autoclave (internal volume 2.1 L) equipped with a stirrer. The autoclave was sealed and maintained at 20°C. The contents of the autoclave were stirred, and hydrogen gas was purged at 10 mL / min for 1 hour. After stirring for another hour to allow the reaction to proceed, the mixture was filtered and the crude reaction liquid in the autoclave was recovered.

[0102] The recovered crude reaction liquid was dried with molecular sieve 3A and then distilled to obtain a mixture of HFE-77-12 and hydroadduct (HFE-77-12 95.3 mol%, hydroadduct 4.7 mol%).

[0103] [Example 4]

[0104] 100 g of a 24% (w / w) potassium hydroxide aqueous solution was added to the crude product obtained in Example 1. The mixture was stirred at 120 °C for 3 hours to perform phase separation and washing with distilled water. The product was then dried using molecular sieve 3A to obtain an organic layer (HFE-77-12 95.3 mol%, de-HF derivative 0.01 mol%, methoxy-substituted derivative 4.6 mol%, no fluorinated carboxylic acid detected). The organic layer was then distilled to obtain a purified product (HFE-77-12 99.99 mol%, de-HF derivative 0.01 mol%).

[0105] In Examples 1-4, a decrease in the concentration of the deHF agent was confirmed by the mixture of HFE-77-12 and the deHF agent.

Claims

1. A method for reducing the concentration of hydrofluoroether olefins, comprising reducing the concentration of hydrofluoroether olefins in a mixture containing hydrofluoroethers and hydrofluoroether olefins. The hydrofluoroether is compound (A) represented by the following formula (1). The hydrofluoroether olefin is compound (B) represented by the following formula (2). The compound (B) in the mixture is reacted with any one of the following compounds (C): alcohol, chlorine, and hydrogen. R 2 -O-R 1 -O-R 3 (1) R 2 -O-R 1 -O-R 4 (2) In equations (1) and (2), R 1 It is an alkylene group having 1 to 4 carbon atoms. R 2 and R 3 Each is independently a fluoroalkyl group having 2 to 4 carbon atoms. R 4 It is a fluoroolefin with 2 to 4 carbon atoms.

2. The method for reducing the concentration of hydrofluoroether olefins according to claim 1, wherein, The difference in boiling points between compound (A) and compound (B) is less than 10°C.

3. The method for reducing the concentration of hydrofluoroether olefins according to claim 1, wherein, Compound (C) is an alcohol or chlorine gas. The boiling point of compound (D), obtained by reacting compound (B) with alcohol or chlorine, is more than 15°C different from that of compound (A).

4. The method for reducing the concentration of hydrofluoroether olefins according to claim 3, wherein, The crude product obtained by reacting the mixture with compound (C) is distilled to separate and remove compound (D).

5. The method for reducing the concentration of hydrofluoroether olefins according to claim 1, wherein, The alcohol is a primary alcohol.

6. The method for reducing the concentration of hydrofluoroether olefins according to claim 5, wherein, The primary alcohol is methanol, ethanol, or 1-propanol.

7. The method for reducing the concentration of hydrofluoroether olefins according to claim 1, wherein, Compound (C) is hydrogen gas.

8. The method for reducing the concentration of hydrofluoroether olefins according to claim 1, wherein, Compound (A) is 1,1,1,2,3,3-hexafluoro-3-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]propane, and compound (B) is 1,2,3,3,3-pentafluoro-1-[2-(1,1,2,3,3,3-hexafluoropropoxy)ethoxy]-1-propene.

9. A hydrofluoroether-containing composition with reduced concentration of hydrofluoroether olefin, obtained by the method for reducing the concentration of hydrofluoroether olefin according to any one of claims 1 to 8.

10. A heat medium, which is the hydrofluoroether-containing composition of claim 9.

11. The heat transfer medium according to claim 10, used for cooling or heating constituent components in a semiconductor manufacturing apparatus.