JP2007039376A - Method for producing hydrofluoroether (hfe) - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an industrial method for producing HFE-254pc (1-methoxy-1,1,2,2-tetrafluoroethane) highly safely and economically. <P>SOLUTION: The method for producing hydrofluoroether comprises (1) a process for reacting a fluoroolefin with an alcohol in the presence of a basic catalyst and an aprotic solvent and/or a crown ether used as an additive, (2) a process for taking out a reaction product from a reactor, separating it from the unreacted raw material and purifying the reaction product after drying, and (3) a process for returning the unreacted raw material comprising the separated catalyst, the aprotic polar solvent and/or the alcohol to the reactor and reacting a fluoroolefin with an alcohol. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an industrial process for producing hydrofluoroether (HFE). More specifically, it is an industrial scale production method of 1-methoxy-1,1,2,2-tetrafluoroethane (hereinafter sometimes referred to as HFE-254pc), and is continuous, semi-continuous or discontinuous. It relates to a method of manufacturing. The present invention also relates to a method for producing difluoroacetate, which is useful as an intermediate raw material for medicines and agricultural chemicals, highly functional materials and the like.

  As a method for producing hydrofluoroether, it is known to react a fluoroolefin compound and an alcohol in the presence of a basic catalyst. For example, in Non-Patent Document 1, tetrafluoroethylene (TFE) and methanol are reacted in the presence of sodium methoxide to produce 1-methoxy-1,1,2,2-tetrafluoroethane (HFE-254pc). A method is disclosed. However, in this method, a high pressure is required to advance the reaction, but the reaction rate is small and there is a problem in productivity despite the high pressure condition. In addition, under high pressure conditions, tetrafluoroethylene has an explosive property and thus has a problem in safety, and has a drawback that a cost load of a reaction facility or the like increases.

  Patent Document 1 discloses a method for producing HFE-254pc under relatively mild conditions. However, even in this method, the reaction rate is not sufficient, and the reaction method is a discontinuous batch (batch) reaction in which raw materials other than TFE are charged in a lump. It is not described and is not necessarily suitable as a method for manufacturing on a large scale.

In order to manufacture industrially, it is necessary to construct a continuous, semi-continuous or discontinuous process including not only reaction but also separation and purification and recovery and reuse of raw materials. When a potassium hydroxide catalyst is used in the HFE-254pc synthesis reaction, insoluble salts such as potassium difluoroacetate and potassium fluoride that cause plugging of the pipe and the like are precipitated in the continuous process, particularly in a continuous process. It is necessary to control the concentration of the reaction product removed from the vessel. In addition, since methanol and HFE-254pc, which are raw materials in the separation and purification step, form an azeotropic composition and cannot be purified by simple distillation, it is necessary to devise separation and recovery techniques.
J. et al. Am. Chem. Soc. , Vol 73, 1329 (1951) Japanese Patent No. 3632243

  An object of the present invention is to provide an industrial production method of HFE-254pc which is safe and economical.

  As a result of intensive studies on industrially useful production methods of hydrofluoroethers to solve the above problems, the present inventors have found that in the presence of aprotic solvents and / or crown ethers using fluoroolefins as basic catalysts and additives. Thus, the reaction proceeds under mild conditions by reacting with alcohol, and a method for efficiently producing by separating, purifying and reusing the latter stage continuously, semi-continuously or discontinuously was found and the present invention was achieved. It was.

  That is, this invention provides the industrially advantageous manufacturing method of hydrofluoro ether, and consists of the following process.

(1) A step of reacting with an alcohol in the presence of an aprotic solvent and / or crown ether using a fluoroolefin as a basic catalyst and an additive (2) The reaction product is taken out of the reactor and separated from unreacted raw materials. The step of purifying the reaction product after drying (3) The step of returning the unreacted raw material containing the catalyst, the aprotic polar solvent and / or the alcohol back to the reactor and reacting the fluoroolefin with the alcohol. In the above production method, the hydrofluoroether is 1-methoxy-1,1,2,2-tetrafluoroethane, the fluoroolefin is tetrafluoroethylene, and the alcohol is methanol.

  In the present invention, the aprotic polar solvent is at least one selected from the group consisting of a sulfoxide compound, a sulfolane compound, an amide compound, a nitrile compound, an ether compound, an amine compound, an oxazoline compound, and a phosphate ester compound. It is said manufacturing method characterized by this.

 In the present invention, the crown ether is at least one selected from the group consisting of 18-crown-6 ether, 15-crown-5 ether, and 12-crown-4 ether. It is.

  Further, in the present invention, the basic catalyst is an alkali metal oxide, an alkaline earth metal oxide, an alkali metal hydroxide, an alkaline earth metal hydroxide, an amine compound, or a basic salt. Sodium oxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, cesium hydroxide, lithium hydroxide, sodium carbonate, potassium carbonate, magnesium carbonate, cesium carbonate, lithium carbonate, potassium methoxide, potassium ethoxide, sodium methoxide, It is a production method characterized by using at least one selected from the group consisting of sodium ethoxide.

  1-Methoxy-1,1,2,2-tetrafluoroethane produced according to the present invention is a foaming agent, solvent, cleaning agent, heat transfer medium, working fluid, reaction solvent for rigid polyurethane foam instead of hydrofluorocarbon (HFC) It is useful as a solvent for paint, extractant, drainer, desiccant, propellant and the like.

According to the production method of the present invention, HFE-254pc can be produced efficiently and economically on an industrial scale.

  The present invention provides an industrially advantageous method for producing hydrofluoroether, and comprises three steps: (1) a reaction step, (2) a separation and purification step, and (3) a reuse step. In particular, in the reaction process, the use of an aprotic solvent and / or crown ether as an additive promotes the reaction rate, so that the yield can be increased, and it can be produced under mild reaction conditions (temperature, pressure). it can.

  Since the load related to the subsequent separation and purification process is reduced, the separation and purification efficiency of the produced HFE is improved, and industrial production becomes possible. In addition, a highly productive manufacturing method could be established by collecting and recycling raw materials and additives.

Examples of the alcohol used in the method of the present invention include C _m H _n X _p OH (where X is Cl, F represents an atom, m is an integer from 1 to 20, n and p are integers from 0 to 41, and n + p = 2m + 1), such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, trifluoroethanol, hexafluoropropanol, and the like, and methanol is particularly preferable.

As the fluoroolefin, C _x H _{y X z} (where X is Cl, .2x = y + Z representing F atoms, x = 2 to 6 integer, integer y = 0~11, z = 1 A haloolefin represented by, for example, tetrafluoroethylene, trifluoroethylene, vinylidene fluoride, vinyl fluoride, hexafluoropropene, 3,3,3-trifluoropropene 1,1,3,3,3-pentafluoropropene, 1,3,3,3-tetrafluoropropene, 1-chloro-3,3,3-trifluoropropene, etc. preferable.

  Although it does not specifically limit regarding manufacture of the fluoro olefin which is a raw material, The method of manufacturing by the thermal decomposition reaction of chlorofluoro alkane is known. For example, tetrafluoroethylene or hexafluoropropene can be produced by a thermal decomposition reaction of chlorodifluoromethane, and purified tetrafluoroethylene and hexafluoropropene are obtained by distillation separation.

  In the present invention, the combination when methanol is used as the alcohol and tetrafluoroethylene is used as the fluoroolefin is optimal, and 1-methoxy-1,1,2,2-tetrafluoroethane (HFE-254pc) is produced. Can do. In the following, the best mode will be shown by taking the production method of HFE-254pc as an example.

  In the method of this application, it can carry out by a continuous process, a semi-continuous process, and a discontinuous process. In the present application, each process represents the following steps.

  The continuous process is a system in which reaction raw materials, a solvent, a catalyst, and the like are continuously supplied to the reactor in order to maintain a steady state in the reaction, and the product produced by the reaction is continuously extracted from the reactor. . Further, by continuously moving the separation / recovery and recycling steps in the latter stage directly connected to the reactor in proportion to the production rate of the product, all the steps are integrated to produce the target product.

  The semi-continuous process means, for example, that an excess of one reaction raw material or catalyst is previously charged in a reactor and the other reaction raw material is continuously supplied to complete the reaction, or the raw material, catalyst or the like is reacted in advance. In this method, the product is charged all at once and the product is continuously extracted. In this case, a steady state of the reaction is not formed. The subsequent separation and recovery step can be operated independently of the reactor.

  The discontinuous process refers to a system in which raw materials, catalysts, etc. are previously charged into a reactor in advance, the reaction is completed, and the product after reaction is withdrawn in a batch. The latter separation and recovery step is the same as the semi-continuous process.

  In a continuous process, methanol, TFE, solvent and basic catalyst are continuously introduced into the reactor. During the reaction, HFE-254pc is continuously extracted together with unreacted methanol, a solvent and a basic catalyst at a reaction rate capable of controlling the formation of insoluble solids, and the solids are removed by a filter or the like and introduced into a flash distillation column. The HFE-254pc / methanol azeotrope distilled from the flash distillation column is recovered, and most of the methanol, solvent, basic catalyst, etc. remaining at the bottom of the distillation column are returned to the reactor. In the HFE-254pc / methanol azeotropic composition, methanol is removed by washing with water or extractive distillation. After dehydration in the drying tower, high-purity HFE-254pc is obtained in the precision distillation tower. Methanol recovered in water or solvent is distilled, dried and again used for the reaction.

  In a semi-continuous process, methanol, TFE, solvent and basic catalyst are charged into a reactor in a predetermined amount and reacted at a predetermined pressure and temperature condition, and the product is continuously extracted or only TFE is continuously used. Then, the reaction is allowed to proceed, the reaction is allowed to proceed, the reaction is stopped, the product is taken out, and HFE-254pc can be separated and purified in the same manner as in the continuous process. Unreacted raw materials are subjected to the reaction again after separation.

In a discontinuous process, methanol, TFE, solvent, and basic catalyst are charged into a reactor in a predetermined amount and reacted at a predetermined pressure and temperature. After the reaction is stopped, the product is taken out and is the same as in the continuous process. Thus, HFE-254pc can be separated and purified.
Also in this case, unreacted raw materials can be subjected to the reaction again after separation.

  Difluoroacetate, KF, and the like produced by the side reaction have low solubility in HFE-254pc, increase the methanol conversion, and precipitate as an insoluble solid in the reaction solution when the HFE-254pc concentration increases. Precipitation of solids is a major problem in large-scale industrial production because it leads to reactor scaling and piping blockage. Therefore, control of solid matter production is important to facilitate the manufacturing process.

  The by-product difluoroacetic acid is a reaction of HFE-254pc, which is the main reaction product generated in this reaction, with raw material alcohol and catalyst alkali metal hydroxide. By adjusting the reaction conditions, The amount of by-products generated can be controlled.

CF ₂ HCF ₂ OCH ₃ + CH ₃ OH + 3KOH → CF ₂ HCOOK + CH ₃ OCH ₃ + 2KF + 2H ₂ O

First, the reaction process of HFE-254pc will be described.

  In the continuous process, the introduction ratio of methanol and TFE is continuously introduced into the reactor while keeping the molar ratio of methanol and TFE constant so as to control the production of insoluble solids. In the production of HFE-254pc, the molar ratio of methanol / TFE introduction is 1 / 0.2 to 1 / 0.8, preferably 1 / 0.3 to 1 / 0.6.

  In a discontinuous or discontinuous process, even if solids are precipitated, there is no problem as much as in the continuous process. Therefore, the methanol / TFE charge molar ratio is 1 / 0.5 to 1/1, preferably 1 / 0.0. 6 to 1 / 0.9.

  If the relative amount of methanol to TFE is too small, the methanol and TFE feed composition is economically disadvantageous because the TFE conversion rate decreases and the TFE basic unit becomes large. If the rate is high (high concentration of HFE-254pc) and by-products (difluoroacetate, dimethyl ether, etc.) increase, the reaction yield will decrease, and conversely if too much, the productivity per unit volume of the reactor will decrease. This is not preferable because the load on the separation / purification step and the reuse step increases.

  In the present invention, an aprotic polar solvent and / or a crown ether is added as an additive. By using an aprotic solvent and / or a crown ether, the activity of the base catalyst can be increased to stabilize the cation.

  Although it does not specifically limit as an aprotic polar solvent used with the manufacturing method of this invention, A sulfoxide compound, a sulfone compound, a nitrile compound, an ether compound, a phosphoric acid amide compound, an amide compound, an amine compound, etc. can be used conveniently.

  Examples of the sulfoxide compound include dimethyl sulfoxide (DMSO) and diethyl sulfoxide, and dimethyl sulfoxide is particularly preferable.

  Examples of the sulfolane compound include sulfolane and methyl sulfolane, and sulfolane is particularly preferable.

  Examples of amide compounds include N, N-dimethylacetamide (DMAc), N, N-dimethylacetoacetamide, N, N-diethylacetamide, dimethylformamide (DMF), 2-pyrrolidone, and N-methyl-2-pyrrolidone (NMP). Hexamethylphosphoric triamide (HMPA), 1,3-dimethyl-2-imidazolinodine and the like, and N-methyl-2-pyrrolidone (NMP) and N, N-dimethylacetamide (DMAc) are particularly preferable. .

  Examples of the nitrile compound include acetonitrile, propionitrile, butyronitrile, isobutyronitrile, benzonitrile and the like, and acetonitrile and propionitrile are particularly preferable.

  Examples of ether compounds include monoglyme, diglyme, triglyme, tetraglyme, diethyl ether, diisopropyl ether, di-n-butyl ether, t-butyl methyl ether, cyclopentyl methyl ether, tetrahydrofuran (THF), tetrahydropyran, 1,4-dioxane, Examples include 1,3-dioxolane, anisole, morpholine, and monoglyme and diglyme are particularly preferable.

  Examples of the phosphoric acid ester compound include trimethyl phosphate, triethyl phosphate, tributyl phosphate, tris (2-ethylhexyl) phosphate, tricresyl phosphate and the like, and trimethyl phosphate and tributyl phosphate are particularly preferable.

  Examples of the amine compound include triethylamine, n-butylamine, di-n-butylamine, tri-n-butylamine, n-octylamine, 2-ethylhexylamine, pyridine, quinoline and the like, and triethylamine and n-butylamine are particularly preferable.

  Examples of the oxazoline compound include oxazoline, 2-methyloxazoline, 2-phenyloxazoline, oxazolidine, and oxazoline is particularly preferable.

  Furthermore, in this invention, a cation is stabilized by adding crown ether. This increases the reactivity of the alkoxy ions involved in the reaction. .

  Examples of the crown ether used include 18-crown-6 ether, 15-crown-5 ether, 12-crown-4 ether, etc. Among them, 18-crown-6 ether is the most in combination with potassium ion. preferable.

  The amount of the solvent used is 5 mol% to 50 mol%, preferably 10 mol% to 40 mol%, based on the alcohol, regardless of the type of continuous or discontinuous process. If the amount of the solvent is too small, the reaction rate is lowered and the productivity is lowered. On the other hand, if the amount is too large, it is difficult to control the reaction temperature and pressure due to a sudden rise in the heat of reaction. Since productivity falls, it is not preferable. If there is too much water in the reaction system, the progress of the reaction is hindered. Therefore, it is preferable that the solvent is previously dried, dehydrated, etc. to control the water concentration in the reaction system.

  The basic catalyst in this reaction is not particularly limited as long as it is a base that efficiently promotes the above reaction, but alkali metal oxides, alkaline earth metal oxides, alkali metal hydroxides, alkaline earth metals A hydroxide, an amine compound, a basic salt, etc. are mentioned.

  Examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, cesium hydroxide, and lithium hydroxide. Among these, sodium hydroxide, potassium hydroxide, and the like are included. preferable.

  Examples of the alkali metal alkoxide include potassium methoxide, potassium ethoxide, potassium propoxide, potassium butoxide, sodium methoxide, sodium ethoxide, sodium propoxide, sodium butoxide, etc. Among these, potassium methoxide, potassium ethoxide Sodium methoxide and sodium ethoxide are preferred.

  Examples of the carbonate include sodium carbonate, potassium carbonate, magnesium carbonate, cesium carbonate, lithium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, magnesium hydrogen carbonate, cesium hydrogen carbonate, lithium hydrogen carbonate and the like. Of these, sodium carbonate and potassium carbonate are preferred.

  Further, activated alumina carrying KF as a solid catalyst can be suspended in the reaction solution. The amount of the basic catalyst to be used can be reacted in the range of 0.1 mol% to 15 mol%, preferably 0.5 mol% to 10 mol%, regardless of the type of continuous or discontinuous process. Well, more preferably 1 mol% to 5 mol%. If the amount of the basic catalyst is too small, the reaction rate is slow and the productivity is lowered. If the amount is too large, it is difficult to control the reaction temperature because of the rapid reaction heat, and the amount of precipitated solid matter increases due to side reactions. Is complicated and economically undesirable.

  The method of the present invention can be carried out under relatively mild conditions. Since TFE increases the risk of explosion and the like when the pressure is increased, mild reaction conditions are an important requirement for safe handling of TFE. That is, the mild reaction condition is a condition that can avoid the explosion risk of TFE. For this reason, it is necessary to avoid a temperature rise accompanied by a sudden pressure increase.

  Although the reaction pressure is not particularly limited, a high pressure is not required because the reaction rate is remarkably increased in the method of the present invention. The reaction pressure is 0.1 MPa to 1.0 MPa regardless of the type of continuous or discontinuous process. Yes, preferably from 0.1 MPa to 0.6 MPa. In the present invention, the target HFE-254pc can be produced even under mild pressure conditions from normal pressure to slight pressure.

  Although the reaction temperature is not particularly limited, it can be carried out under relatively mild temperature conditions, and is in the range of 0 ° C. to 100 ° C., preferably 20 ° C. to 80 ° C., regardless of the type of continuous or discontinuous process. Preferably 30 to 70 degreeC is good. If the reaction temperature is too low, the reaction does not proceed, and if it is too high, the probability of a side reaction increases, which is economically undesirable.

  Next, the separation and purification process will be described.

The reaction product is discharged as a crude reaction solution as it is or taken out from the reactor by distilling it through a reflux tower provided at the top of the reactor, and the reaction product separated from unreacted raw materials and by-products is dried. Purify by distillation.

  Finally, the reuse process will be described.

  The unreacted raw material containing the separated catalyst, aprotic polar solvent and / or alcohol is returned to the reactor and reused in the reaction.

  The manufacturing process in the present invention described above will be described below with reference to FIG. 1 by taking a continuous process method as an example.

  The reaction is carried out in the presence of a catalyst and an additive that accelerates the reaction under reaction conditions sufficient for the addition reaction of the fluoroolefin and alcohol to proceed. For example, in the production of HFE-254pc, a basic catalyst, methanol, and a solvent are introduced into the reaction vessel 1 in advance to start the reaction, and TFE is introduced after sufficient nitrogen substitution. In order to efficiently perform the reaction, it is desirable to introduce TFE into the reaction solution while forming fine bubbles with a filter or the like, thereby increasing the contact efficiency between TFE and the reaction solution.

  Moreover, the opportunity of contact with TFE, methanol, and a catalyst can be raised by fully stirring. When the reaction reached the desired methanol conversion (30-60%), methanol / TFE, catalyst methanol solution and solvent were continuously introduced to maintain the methanol conversion, while the HFE-254pc produced A reaction liquid equivalent to the amount of the raw material introduced containing is continuously extracted from the reactor 1. As another method for extracting the product, the reaction temperature may be increased, gasified, and distilled through a reflux tower provided at the top of the reactor.

  The extracted reaction crude product is once recovered in a receiving tank to remove low boiling point components and dissolved TFE. If the reaction crude product contains solids, the solids are removed and separated by filter filtration 2 (or centrifugation, etc.) and then introduced into the first distillation column (flash distillation) 3.

  The separation conditions in the first distillation column 3 are known as long as the distillate component becomes an azeotropic composition of HFE-254pc / methanol (HFE-254pc: 85 mol%, methanol: 15 mol%). can do. The main components of the high boilers discharged from the bottom of the first distillation column are methanol, a solvent and a catalyst, which are introduced again into the reactor as they are or after filtration and used as raw materials.

  The HFE-254 pc / methanol azeotrope composition is introduced into the washing tank 4, and methanol is extracted and removed with water and transferred to the two-layer separation tank 5. The amount of water used in the washing step is not particularly limited as long as methanol can be sufficiently removed, but is preferably in the range of 0.5 to 5 kg with respect to 1 kg of the azeotropic composition. Further, by adding an inorganic salt to the washing water, the amount of HFE-254pc dissolved in the aqueous phase can be reduced and the separability can be improved. The inorganic salt is not particularly limited, but neutral salts such as sodium chloride and potassium chloride are preferable.

  The washed water is sent to the methanol recovery distillation column 6, where the methanol is recovered and returned to the reaction. The water excluding methanol is also sent to the washing tank 4 again as washing water.

  Since HFE-254pc after washing contains a trace amount of water, troubles such as bringing in a trace amount of methanol and freezing in the second distillation column described later may occur. Therefore, the dehydration process is performed through the drying tower 7. The method of dehydration is not particularly limited, but a method of contacting HFE-254pc with a dehydrating agent is preferable. For example, a drying tower packed with sulfuric acid, silica gel, molecular sieves or the like is desirable.

  The removal of methanol can also be performed by extractive distillation using a solvent instead of the azeotropic distillation, water washing and drying steps described above. As the solvent to be used, water may be used, but an aprotic polar solvent having an affinity for methanol is preferable, and it is particularly preferable to use the solvent in common with the solvent used in the reaction. Although the methanol extracted into the solvent by extractive distillation can be returned to the reactor as it is, when it is necessary to control the solvent concentration in the reactor, the methanol is separated and reused by distillation.

  The crude product thus obtained is further divided into a second distillation column 8 for fractionating low boiling substances such as dimethyl ether contained in a trace amount and a third distillation column 9 for fractionating high boiling substances contained in a trace amount. Purified.

  As the separation conditions in the second distillation column 8, a known one can be adopted as long as it can separate low-boiling substances from HFE-254pc. In general, conditions of normal pressure and tower top temperature of −30 to −40 ° C. are preferably employed. As the separation conditions in the third distillation column 9, a known one can be adopted as long as it can separate high-boiling substances from HFE-254pc. In general, conditions of normal pressure and tower top temperature of 0 to -40 ° C are preferably employed.

  The basic conditions of the continuous process method described here can be applied to discontinuous or semi-continuous processes by performing each unit operation individually.

  Examples of the present invention will be specifically described below, but the present invention is not limited to these examples.

[Example 1]
A stainless steel 500 ml reactor equipped with a stirrer was charged with 59.33 g (1.85 mol) of methanol, 61.97 g (0.793 mol) of dimethyl sulfoxide and 15.46 g (0.276 mol) of potassium hydroxide, and the reactor was filled with nitrogen. Replaced. After raising the reactor internal temperature to 40 ° C. in a water bath, TFE was introduced into the raw material liquid stirred and mixed at 500 rpm, and the reaction pressure was maintained at 0.4 to 0.5 MPa. The reaction temperature rose to about 50 ° C. due to the heat of reaction. The reaction was continued until the absorption of TFE almost stopped, and the reaction was terminated after 6 hours of introduction of 160.50 g (1.605 mol) of TFE.
[Example 2]
After the reaction, the reaction solution was extracted, and the precipitated white solid was quickly filtered using a vacuum filter. The obtained reaction liquid was distilled using a glass single distillation apparatus (flash distillation column). The refrigerant temperature of the condenser was set to −20 ° C., and the bottom was heated to 40 to 95 ° C. using a water bath. By distillation, 210.4 g of HFE-254pc / methanol azeotrope (molar ratio 85/15, boiling point 34-35 ° C.) was fractionated from unreacted methanol and dimethyl sulfoxide.
[Example 3]
The fractionated azeotropic composition was placed in a 200 ml glass separatory funnel that had been cooled in advance. Washing was carried out 3 times with 50 ml of a pre-ice-cooled saturated saline solution. The washed crude product was dehydrated and dried using Molecular Sieves 4A to obtain 180.1 g of HFE-254pc having a purity of 98.2 GC%.
[Example 4]
Using the obtained crude product as a filler, Using a precision distillation apparatus made of glass with a theoretical plate number of about 40 using 2 was purified. Distillation was performed by setting the refrigerant temperature to −20 ° C. and heating the distillation bottom to 40 to 50 ° C. After 30 minutes of total reflux, low boiling point compounds such as dimethyl ale were separated at a reflux ratio (total reflux: distillation) of 100: 0.5 to 1 second. The reflux ratio was changed to 5 to 10: 1 when the column top temperature was close to the boiling point (37 ° C.) of HFE-254pc and the distillate composition was 99.5 GC% or more of HFE-254pc. After distillation, 169.5 g (1.28 mol) of HFE-254pc with a purity of 99.9 GC% was obtained.
[Comparative Example 1]
A stainless steel 100 ml autoclave was charged with 7.94 g (0.248 mol) of methanol and 0.73 g (0.276 mol) of potassium hydroxide. Stirring was performed using a magnetic stir bar, and the temperature inside the reactor was raised to 40 ° C. in a water bath. The introduction of TFE was started, the reaction pressure was maintained at 0.5 MPa, and the reaction was performed for 1 hour. The reaction solution was analyzed by gas chromatography, and the yield based on methanol was calculated using a calibration curve. The results are shown in Table 1.
[Example 5]
A stainless steel 100 ml autoclave was charged with 7.94 g (0.248 mol) of methanol, 2.24 g (0.0287 mol) of dimethyl sulfoxide and 0.73 g (0.0112 mol) of 86% potassium hydroxide. Stirring was performed using a magnetic stir bar, and the temperature inside the reactor was raised to 40 ° C. in a water bath. The introduction of TFE was started, the reaction pressure was maintained at 0.5 MPa, and the reaction was performed for 1 hour. The reaction solution was analyzed by gas chromatography, and the yield based on methanol was calculated using a calibration curve. The results are shown in Table 1.
[Examples 6 to 32]
The reaction was performed in the same manner as in Example 2 except that 0.0287 mol of various solvents were used instead of dimethyl sulfoxide. The results are shown in Table 1.
[Example 33]
The reaction was conducted in the same manner as in Example 2 except that 1.34 g (0.0051 mol) of 18-crown-6 ether was used instead of dimethyl sulfoxide. The results are shown in Table 1.

[Examples 34 to 41]
The reaction was performed in the same manner as in Example 2 except that 0.0112 mol of various base catalysts were used instead of sodium hydroxide. The results are shown in Table 2.

It is a schematic diagram of a reactor suitable for carrying out the method of the present invention.

Claims (5)

In the production method of hydrofluoroether,
(1) reacting with an alcohol in the presence of an aprotic solvent and / or a crown ether using a fluoroolefin as a basic catalyst and an additive;
(2) removing the reaction product from the reactor, separating it from the unreacted raw material, and drying and purifying the reaction product; and (3) an unreacted raw material containing a catalyst, an aprotic polar solvent and / or an alcohol. Is returned to the reactor, and the process comprises the step of reacting the fluoroolefin with the alcohol. The production method according to claim 1, wherein the hydrofluoroether is 1-methoxy-1,1,2,2-tetrafluoroethane, the fluoroolefin is tetrafluoroethylene, and the alcohol is methanol. The aprotic polar solvent is at least one selected from the group consisting of a sulfoxide compound, a sulfolane compound, an amide compound, a nitrile compound, an ether compound, an amine compound, an oxazoline compound, and a phosphate ester compound. The manufacturing method of Claim 1 or Claim 2. The crown ether is at least one selected from the group consisting of 18-crown-6 ether, 15-crown-5 ether, and 12-crown-4 ether. The manufacturing method as described in. The basic catalyst is at least one selected from the group consisting of alkali metal oxides, alkaline earth metal oxides, alkali metal hydroxides, alkaline earth metal hydroxides, amine compounds, basic salts, and alkali metal alkoxides. The manufacturing method according to any one of claims 1 to 4, wherein:

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