Method for producing 3-chloro-1,1,2,2-tetrafluoropropane and method for producing 1-chloro-2,3,3-trifluoropropene

Abstract

Provided is an efficient method for producing 244ca at high purity.　This method for producing 3-chloro-1,1,2,2-tetrafluoropropane involves reacting 1,1,2,2-tetrafluoropropane with chlorine to obtain 3-chloro-1,1,2,2-tetrafluoropropane.

Description

Technical Field

[0001] The present invention relates to a method for producing 3-chloro-1,1,2,2-tetrafluoropropane and a method for producing 1-chloro-2,3,3-trifluoropropene.

Background Art

[0002] 3-chloro-1,1,2,2-tetrafluoropropane (CHF2-CF2-CH2Cl, HCFC-244ca, hereinafter also referred to as 244ca) is used as a new cleaning agent, refrigerant, foaming agent, solvent, and aerosol, or as a synthetic raw material thereof. For example, Patent Document 1 describes that 244ca is used as a synthetic raw material for producing 1-chloro-2,3,3-trifluoropropene (CHF2-CF=CHCl, HCFO-1233yd, hereinafter also referred to as 1233yd). As a method for producing 244ca, Patent Document 2 describes a method for producing 244ca in which 2,2,3,3-tetrafluoropropanol (hereinafter also referred to as TFPO) is used as a synthetic raw material and reacted with thionyl chloride as a chlorinating agent in the presence of N,N-dimethylformamide.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The method for producing 244ca described in Patent Document 2 uses thionyl chloride as a chlorinating agent, resulting in the presence of by-products such as hydrogen chloride and sulfur dioxide in the reaction product, which require neutralization with a large amount of alkaline aqueous solution. Therefore, research is being conducted on a method for producing 244ca that is suitable for large-scale industrial production. The present invention aims to provide an industrially advantageous method for producing high-purity 244ca. [Means for solving the problem]

[0005] As a result of diligent research to solve the above problems, the inventors have found that the above problems can be solved by the following configuration.

[0006] [1] A method for producing 3-chloro-1,1,2,2-tetrafluoropropane, comprising reacting 1,1,2,2-tetrafluoropropane with chlorine. [2] The method for producing the product according to [1], wherein in the reaction of 1,1,2,2-tetrafluoropropane with chlorine, the reaction product contains 1,3-dichloro-1,1,2,2-tetrafluoropropane in an amount of 10% by mass or less relative to the total amount of 3-chloro-1,1,2,2-tetrafluoropropane and 1,3-dichloro-1,1,2,2-tetrafluoropropane. [3] The manufacturing method according to [1] or [2], wherein 0.01 to 3 moles of the above chlorine are used per mole of the above 1,1,2,2-tetrafluoropropane. [4] A method of production according to any one of [1] to [3], wherein the reaction of 1,1,2,2-tetrafluoropropane with the above chlorine is carried out in the liquid phase. [5] The manufacturing method according to [4], wherein the reaction temperature of the above reaction is -20 to 100°C. [6] The manufacturing method according to [4] or [5], wherein the reaction time of the above reaction is 1 second to 100 hours. [7] The manufacturing method according to any one of [4] to [6], wherein the pressure of the above reaction is 0 to 1 MPa in gauge pressure. [8] A manufacturing method according to any one of [4] to [7], wherein the 1,1,2,2-tetrafluoropropane is continuously supplied to a reactor and the reaction product is continuously withdrawn from the reactor. [9] A method of production according to any one of [4] to [8], wherein the above reaction is carried out in the presence of a solvent.

[10] The method for producing the product according to [9], wherein the solvent is at least one selected from the group consisting of carbon tetrachloride, 1,1,2-trichloro-1,2,2-trifluoroethane, 1-chloro-1,1,2,2-tetrafluoropropane, 1,3-dichloro-1,1,2,2-tetrafluoropropane, 1,3,3-trichloro-1,1,2,2-tetrafluoropropane, 1,3,3,3-tetrachloro-1,1,2,2-tetrafluoropropane, 3-chloro-1,1,2,2-tetrafluoropropane, 1,1-dichloro-2,2,3,3-tetrafluoropropane, 1,1,1-trichloro-2,2,3,3-tetrafluoropropane, and 1,3,3,4,4,6-hexachloro-1,1,2,2,5,5,6,6-octafluorohexane.

[11] The method of production according to [9] or

[10] , wherein the solvent is used in an amount of 1 to 4000% by mass relative to the mass of the 1,1,2,2-tetrafluoropropane.

[12] A method for producing the product according to any one of [1] to [3], wherein the reaction between the above 1,1,2,2-tetrafluoropropane and the above chlorine is carried out in the gas phase.

[13] The manufacturing method according to

[12] , wherein the reaction temperature of the above reaction is 50 to 200°C.

[14] The manufacturing method according to

[12] or

[13] , wherein the reaction time of the above reaction is 1 second to 1 hour.

[15] The manufacturing method according to any one of

[12] to

[14] , wherein the pressure of the above reaction is 0 to 1 MPa in gauge pressure. A method for producing 1-chloro-2,3,3-trifluoropropene, characterized by subjecting 3-chloro-1,1,2,2-tetrafluoropropane obtained by the manufacturing method described in any of [1] to

[15] to a dehydrofluorination reaction in the presence of a base or a catalyst.

[17] The method for producing the product according to

[16] , wherein the reaction product obtained by the dehydrofluoride reaction contains 1,3-dichloro-2,3,3-trifluoropropene in an amount of 10% by mass or less relative to the above 1-chloro-2,3,3-trifluoropropene. [Effects of the Invention]

[0007] According to the present invention, a highly pure and efficient method for producing 244ca can be provided. [Modes for carrying out the invention]

[0008] In this specification, compound names may be referred to by the abbreviations shown in parentheses after the compound name. In this specification, chlorine refers to chlorine (Cl2) in its molecular state. Unless otherwise specified, pressure refers to gauge pressure.

[0009] When a compound has isomers, unless otherwise specified, it indicates one or more isomers selected from those isomers. For example, if both Z and E isomers exist, it indicates all meanings: the Z isomer only, the E isomer only, or a mixture of Z and E isomers in any proportion. When (E) or (Z) is appended to the compound name or abbreviation, it indicates the (E) isomer or (Z) isomer of the respective compound. For example, 1233yd(Z) indicates the Z isomer, and 1233yd(E) indicates the E isomer.

[0010] The method for producing 244ca according to the present invention (hereinafter also simply referred to as "the method for producing the present invention") is carried out by a chlorination reaction in which 1,1,2,2-tetrafluoropropane (CHF2-CF2-CH3; HFC-254cb; hereinafter also referred to as 254cb) is reacted with chlorine. The reaction to obtain 244ca by the chlorination reaction of 254cb is the reaction shown in the following formula (1) (hereinafter also referred to as reaction (1)).

[0011] [ka]

[0012] The production method of the present invention surprisingly has the advantage that in the chlorination reaction of 254cb, almost no other chlorinated products are generated and 244ca can be selectively obtained.

[0013] Hereinafter, first, the components used in the production method of the present invention will be described in detail, and then the procedure of the production method will be described in detail.

[0014] (Production method of 254cb) In the production method of the present invention, 254cb is used as a raw material. 254cb is a known compound known as a raw material or intermediate for the production of fluorine-containing compounds. The method for obtaining 254cb is not particularly limited, and known methods described in International Publication No. 2018 / 139654 etc. can be mentioned. Specifically, it can be produced by reacting hydrogen with 1-chloro-1,1,2,2-tetrafluoropropane (CClF2-CF2-CH3. HCFC-244cc. Hereinafter, also referred to as 244cc.) at a temperature exceeding 200 °C in the presence of a catalyst.

[0015] For the above reaction of reducing 244cc by reacting it with hydrogen, a hydrogenation catalyst is used. As the hydrogenation catalyst, a palladium catalyst is preferred. The palladium catalyst may be not only a simple palladium but also a catalyst composed of palladium or a metal catalyst containing palladium. As the metal catalyst containing palladium, a palladium alloy catalyst is preferred. Examples of the palladium alloy catalyst include a palladium / platinum alloy catalyst and a palladium / rhodium alloy catalyst etc. Also, as the palladium catalyst, it may be a mixture of a metal catalyst containing palladium and other metals.

[0016] Also, a catalyst in which the above palladium catalyst is supported on a carrier (hereinafter, also referred to as a palladium-supported catalyst) may be used, or a composite catalyst in which the above palladium catalyst and other metals are separately supported on a carrier may be used.

[0017] Suitable supports for palladium-supported catalysts include activated carbon and metal oxides (alumina, zirconia, silica, etc.). Activated carbon is preferred in terms of activity, durability, and reaction selectivity. Examples of activated carbon include those obtained from plant materials (wood, charcoal, fruit shells, coconut shells, etc.) and mineral materials (peat, lignite, coal, etc.). Activated carbon obtained from plant materials is preferred in terms of catalyst durability, and coconut shell activated carbon is particularly preferred.

[0018] The reduction reaction involving the reaction of 244 cc with hydrogen is preferably carried out in the gas phase. Specifically, a catalyst support is packed into a reaction tube to form a catalyst layer, and 244 cc of gas and hydrogen gas are circulated through the catalyst layer. The temperature of the catalyst layer during the reaction is above 200°C, preferably between 210 and 350°C, and more preferably between 250 and 300°C. The ratio of 244 cc to hydrogen is adjusted as appropriate. Dilution gases such as nitrogen gas and noble gases may also be added to the 244 cc gas and hydrogen gas before the reaction.

[0019] From the reaction product obtained by reacting 244 cc with hydrogen, 254 cb can be isolated by a conventional separation method, for example, by distillation, and used as a raw material for the production method of the present invention.

[0020] The 254cb used as a raw material in the manufacturing method of the present invention may be a mixture with other compounds. In other words, the raw material in the manufacturing method of the present invention only needs to contain 254cb, and for example, a mixture of 254cb and other compounds may be used as a raw material.

[0021] Other compounds that may be included in the raw materials used in the manufacturing method of the present invention include impurities such as raw materials for the production of 254cb and by-products generated in addition to 254cb during the production of 254cb. If the raw materials contain the above-mentioned impurities, the by-products generated from the impurities may be removed by known means such as distillation, extractive distillation, azeotropic distillation, membrane separation, two-phase separation, and adsorption. The impurities are preferably compounds that are inert in the manufacturing method of the present invention.

[0022] In the raw materials used in the chlorination reaction, 254cb is preferably included as a main component. The content of 254cb relative to the total mass of the raw materials used in the chlorination reaction is preferably 50% by mass or more, more preferably 75% by mass or more, even more preferably 80% by mass or more, and particularly preferably 90% by mass or more. The upper limit is 100% by mass.

[0023] (Manufacturing method) In the production method of the present invention, 254cb and chlorine are brought into contact using a reactor to produce 244ca by a chlorination reaction. As the starting material, 254cb obtained by the method described above can be used. However, the method of obtaining 254cb is not limited to this. The production method of the present invention can be carried out in either the liquid phase or the gas phase, but it is preferable to carry it out in the liquid phase reaction because it is more industrially advantageous.

[0024] Here, in the chlorination reaction of 254cb, a side reaction occurs, resulting in 244cc, 1,3-dichloro-1,1,2,2-tetrafluoropropane (CClF2-CF2-CH2Cl; HCFC-234cc; hereinafter also referred to as 234cc), 1,1-dichloro-2,2,3,3-tetrafluoropropane (CHCl2-CF2-CHF2; HCFC-234cb; hereinafter also referred to as 234cb), and 1,3,3-trichloro-1,1,2,2-tetrafluoropropane (CClF2-CF2-CHCl2; HCFC- Chlorinated products such as 224ca (hereinafter also referred to as 224ca), 1,3,3,3-tetrachloro-1,1,2,2-tetrafluoropropane (CClF2-CF2-CCl3; HCFC-214cb; hereinafter also referred to as 214cb), 1,1,1-trichloro-2,2,3,3-tetrafluoropropane (CHF2-CF2-CCl3; HCFC-224cb; hereinafter also referred to as 224cb), and 1,3,3,4,4,6-hexachloro-1,1,2,2,5,5,6,6-octafluorohexane may be produced as by-products.

[0025] Chlorinated products other than 244ca produced as by-products in the chlorination reaction of 254cb can be subjected to hydrogen reduction to produce the target product 244ca or the raw material 254cb. For example, if 244cc is produced as a by-product in the production method of the present invention, 254cb can be produced by reacting 244cc with hydrogen in the presence of a catalyst, and can be reused as a raw material. Also, if 234cc or 234cb is produced as a by-product in the production method of the present invention, 244ca can be produced by reacting 234cc or 234cb with hydrogen in the presence of a catalyst.

[0026] In the chlorination reaction of 254cb, which is the production method of the present invention, it is preferable to carry out the reaction under conditions that suppress the above-mentioned side reactions in order to increase the selectivity of 244ca.

[0027] 244ca, a product of the manufacturing method of the present invention, is a useful compound as a raw material for producing 1233yd. 1233yd is a compound that can be used in various applications as a detergent, refrigerant, foaming agent, solvent, or aerosol. If the raw material containing 244ca contains 234cc, by-products may be generated, which can cause a decrease in the selectivity of 1233yd. Therefore, it is preferable to have a low content of 234cc relative to the raw material containing 244ca. Accordingly, it is preferable to carry out the chlorination reaction of 254cb under conditions that result in a small amount of 234cc being produced relative to the total amount of reaction products.

[0028] In the production method of the present invention, when the reaction product contains 234cc, the content of 234cc is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 1% by mass or less, relative to the total amount of 244ca and 234cc in the reaction product. Within the above range, the generation of by-products is suppressed during the production of 1233yd.

[0029] The reactor is not particularly limited in shape and structure, as long as it can be used to introduce and react 254cb with chlorine. Examples of such reactors include glass reactors, stainless steel reactors, glass-lined reactors, and resin-lined reactors. The reactor is usually equipped with a temperature control unit to adjust the temperature inside the reactor. The temperature control unit should be capable of adjusting the reaction temperature between 254cb and chlorine. Examples of such units include oil baths. The temperature control unit may be integrated into the reactor.

[0030] The manufacturing method of the present invention can be carried out in either the liquid phase or the gas phase, but it is preferable to carry it out in the liquid phase reaction because it is more advantageous for industrial implementation. Carrying it out in the gas phase reaction means reacting gaseous 254cb with gaseous chlorine, and carrying it out in the liquid phase reaction means reacting liquid 254cb with gaseous chlorine.

[0031] In the following, we will first describe in detail the reaction conditions in the liquid phase of the manufacturing method of the present invention, and then describe in detail the reaction conditions in the gas phase.

[0032] (Regarding chlorination reactions carried out in the liquid phase) A specific method for the liquid-phase reaction involves supplying liquid 254cb and gaseous chlorine into a reactor, and then contacting the 254cb with the chlorine in the reactor to obtain 244ca. Furthermore, it is preferable to carry out this reaction under light irradiation.

[0033] In the production method of the present invention, the ratio of 254cb to chlorine, for example, the ratio of 254cb to chlorine supplied to the reactor, is preferably 0.01 to 3 moles, more preferably 0.1 to 2 moles, even more preferably 0.2 to 1.6 moles, and most preferably 0.5 to 1.5 moles of chlorine (Cl2) per mole of 254cb, from the viewpoint of activating the reaction, suppressing the formation of by-products, and increasing the selectivity and yield of 244ca.

[0034] In the manufacturing method of the present invention, the reaction temperature (temperature inside the reactor) is preferably -20 to 100°C, and more preferably 5 to 60°C, when the reaction is carried out in the liquid phase. Within this numerical range, the reaction can be activated and the formation of by-products can be suppressed.

[0035] When the chlorination reaction is carried out in the liquid phase, it may be carried out by a semi-continuous, batch, or continuous method. The reaction time can be the usual time used for each method and can be adjusted as appropriate depending on the progress of the reaction. For example, 1 second to 100 hours is preferred, and 1 second to 10 hours is more preferred. The reaction time is expressed as the contact time between 254cb and chlorine in the reactor. The raw materials may be supplied to the reactor by supplying each component separately, or by supplying each component as a mixture, or by using a combination of these methods. When chlorine is supplied to the reactor as chlorine gas, the chlorine gas may be diluted with an inert gas such as nitrogen gas as needed. When the production method of the present invention is carried out in a continuous manner, the reaction time is the residence time between 254cb and chlorine in the reactor.

[0036] When a chlorination reaction is carried out in a semi-continuous manner, it is preferable to supply the raw materials into the reaction system at a constant rate, either as individual components or as a mixture of the components. The supply of raw materials may be intermittent or continuous. When carrying out a chlorination reaction in a batch manner, it is preferable to load the raw materials into the reactor along with the solvent before the reaction begins.

[0037] When carrying out a chlorination reaction in a continuous manner, the raw materials are supplied continuously and the reaction products are withdrawn continuously. For example, a method in which the raw materials are continuously supplied into the reaction system from the bottom of the reactor where the solvent is charged, and the reaction products are continuously withdrawn from the top of the reactor (such as the overflow method), is preferred. The production method of the present invention is preferably carried out in a continuous manner from the viewpoint of increasing the selectivity of 244ca and suppressing the amount of 234cc produced.

[0038] When the chlorination reaction is carried out in a continuous manner, it is preferable to supply the raw materials and withdraw the product so that the raw materials, 254cb and chlorine, remain in the reactor for 1 second to 100 hours, with the residence time being more preferably 1 second to 50 hours, and particularly preferably 1 second to 10 hours.

[0039] In chlorination reactions carried out in the liquid phase, conventional methods and equipment can be used in any of the semi-continuous, batch, or continuous methods, and it is preferable to carry out the reaction while stirring.

[0040] In the manufacturing method of the present invention, the reaction pressure corresponds to the pressure inside the reactor. The reactor pressure is preferably 0 to 1 MPa, and more preferably 0.05 to 0.5 MPa, for efficient production. The reaction is preferably carried out under pressurized conditions to improve productivity.

[0041] The manufacturing method of the present invention is preferably carried out under light irradiation from the viewpoint of increasing the reaction rate. The wavelength of the light used for irradiation is preferably 200 to 750 nm, and more preferably 250 to 730 nm. If the light has a wavelength of 200 nm or more, the formation of by-products can be sufficiently suppressed, and if the light has a wavelength of 750 nm or less, the reaction will proceed sufficiently. The light used for irradiation may also include light with wavelengths less than 200 nm and light with wavelengths greater than 750 nm.

[0042] When using light irradiation, suitable light sources that can efficiently irradiate light with wavelengths of 200-750 nm include fluorescent lamps, LED lights, incandescent lamps, high-pressure mercury lamps, and halogen lamps. Light sources that generate a lot of heat are undesirable because they make it difficult to keep the internal temperature of the reactor low. High internal temperatures increase internal pressure, requiring increased pressure resistance of the reactor, which is disadvantageous from a cost perspective. Also, high internal temperatures make side reactions more likely to occur. Light sources that generate little heat, such as fluorescent lamps and LED lights, are preferred.

[0043] The method of light irradiation is not particularly limited, as long as it is a method that allows light to be uniformly irradiated throughout the reaction time to the entire reaction system, which includes the starting materials containing 254cb and chlorine, the solvent used as needed, and the product containing 244ca.

[0044] Specific methods of light irradiation include inserting a light source fitted with a jacket into the reaction solution and irradiating the raw materials in the reaction solution with light from inside the solution. The material of the jacket is preferably one that transmits light of wavelengths useful for the above reaction, is inert to the components contained in the reaction solution, and is resistant to corrosion by these components. Furthermore, if the light source generates heat, it is preferable that the jacket has a cooling means depending on the reaction temperature.

[0045] When the manufacturing method of the present invention is carried out in the liquid phase, 254cb and chlorine may be supplied to the reactor separately, or they may be supplied in a pre-mixed state. When the manufacturing method of the present invention is carried out in the liquid phase, a solvent may be used. The solvent is preferably one that can dissolve the raw material components containing 254cb and chlorine, is inert to the raw material components, and is easily separated from the target product containing 244ca by distillation or the like.

[0046] Examples of solvents include carbon tetrachloride and 1,1,2-trichloro-1,2,2-trifluoroethane. Alternatively, 244ca may be used as a solvent, and the by-products 244cc, 234cc, 224ca, 214cb, 234cb, 224cb, and 1,3,3,4,4,6-hexachloro-1,1,2,2,5,5,6,6-octafluorohexane may also be used as solvents. One of these compounds may be used as a solvent alone, or two or more may be used in combination.

[0047] The solvent is preferably carbon tetrachloride, which is low-cost and easily separated from the target product, or 244Ca, which does not require separation.

[0048] The amount of solvent is not particularly limited as long as it is sufficient to dissolve the resulting 244ca, and is preferably 1 to 4000% by mass relative to the raw material 254cb, and more preferably 50 to 3000% by mass.

[0049] (Regarding chlorination carried out by gas-phase reaction) A specific procedure for the gas-phase reaction involves supplying heated 254cb and gaseous chlorine into a reactor, and then contacting the gaseous 254cb with the chlorine in the reactor to obtain 244ca. A gas inert to the above reaction (dilution gas) may be supplied to the reactor, as it is effective in adjusting the flow rate, suppressing by-products, and preventing catalyst deactivation. Specific examples of dilution gases include nitrogen gas, carbon dioxide gas, helium gas, and argon gas.

[0050] In the production method of the present invention, the ratio of 254cb to chlorine, for example, the ratio of 254cb to chlorine supplied to the reactor, is preferably 0.01 to 3 moles, more preferably 0.1 to 2 moles, even more preferably 0.2 to 1.6 moles, and most preferably 0.5 to 1.5 moles of chlorine (Cl2) per mole of 254cb, from the viewpoint of activating the reaction, suppressing the formation of by-products, and increasing the selectivity and yield of 244ca.

[0051] When the chlorination reaction is carried out in the gas phase, from the viewpoint of reactivity, the reaction time is preferably 1 second to 1 hour, the reaction pressure is preferably 0 to 1 MPa, and the reaction temperature is preferably 50 to 200°C. Furthermore, from the viewpoint of increasing the reaction rate, it is preferable to carry out the reaction under light irradiation. The wavelength of the light used for irradiation is preferably 200 to 750 nm.

[0052] The reaction product obtained by a chlorination reaction in the liquid phase or gas phase contains the target product 244Ca, unreacted raw materials, solvent, and by-products such as chlorinated products that are not the target product.

[0053] Conventional separation methods can be used to separate the target product, 244ca, from a product containing 244ca. For example, chlorine can be removed by washing with alkali, followed by distillation to remove the solvent and by-products. Distillation can further purify 244ca to a higher purity, and the desired purity of 244ca can be obtained by repeating the distillation process. In the manufacturing method of the present invention, when the reaction product after the separation step contains 234cc, the content of 234cc is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, and particularly preferably 1% by mass or less, relative to the total amount of 244ca and 234cc in the reaction product. Within the above range, the generation of by-products is suppressed during the production of 1233yd. Furthermore, when separating 244ca by distillation, if components with lower boiling points than 244ca form an azeotrope or pseudo-azeotrope with water, 244ca can be recovered without water by distilling the water along with the lower boiling point components. Specific examples of components with lower boiling points than 244ca include 244cc, 254cb, fluoromethane, difluoromethane, 1,1,1,2-tetrafluoroethane, fluoroethane, 1,2-difluoroethane, and 1233yd(E).

[0054] (1233yd manufactured) 244ca is a useful compound as a raw material for producing 1233yd. 1233yd is a compound that can be used in various applications as a detergent, refrigerant, foaming agent, solvent, or aerosol. 1233yd can be produced by dehydrofluorinating 244ca. One method for producing 1233yd is to dehydrofluorinate 244ca obtained by the production method of the present invention in the presence of either a base or a catalyst. Known methods for the dehydrofluoride reaction include those described in International Publication No. 2016 / 136744.

[0055] The base used in the dehydrofluoridation reaction of 244Ca includes metal hydroxides, metal oxides, or metal carbonates, with metal hydroxides being preferred in terms of reaction time and reaction yield, and potassium hydroxide or sodium hydroxide being particularly preferred. The catalyst used in the dehydrofluoridation reaction of 244Ca is preferably a correlation transfer catalyst. Examples of correlation transfer catalysts include quaternary ammonium salts, quaternary phosphonium salts, quaternary arsonium salts, sulfonium salts, crown ethers, etc., with quaternary ammonium salts being particularly preferred, and among quaternary ammonium salts, tetra-n-butylammonium chloride (TBAC), tetra-n-butylammonium bromide (TBAB), and methyltri-n-octylammonium chloride (TOMAC) are particularly preferred.

[0056] The dehydrofluorination reaction of 244Ca can be carried out in either a liquid-phase or gas-phase manner. A liquid-phase reaction refers to the dehydrofluorination reaction of 244Ca in a liquid state or dissolved in a liquid. A gas-phase reaction refers to the dehydrofluorination reaction of 244Ca in a gaseous state. 1233yd produced using 244ca obtained by the production method of the present invention has high purity and low content of by-products such as 1,3-dichloro-2,3,3-trifluoropropene (CClF2-CF=CHCl; HCFO-1223yd; hereinafter also referred to as 1223yd), making it suitable for various applications. In particular, when 1233yd is produced using reaction raw materials containing 244ca, which has a low content of 234cc, the amount of 1223yd produced as a by-product can be reduced, thus simplifying the process required for purifying 1233yd and offering economic advantages. Although 1223yd is a compound that is difficult to separate from 1233yd by distillation because it forms an azeotrope with 1233yd, the above method makes it possible to provide 1233yd with a purity of 90% or more in an industrially advantageous manner.

[0057] In the solvent composition obtained by the manufacturing method of the present invention, the content of 1223yd relative to the total amount of 1233yd and 1223yd is preferably 10% by mass or less, more preferably 5% by mass or less, even more preferably 3% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less.

[0058] In the production method of the present invention, in addition to the target product 1233yd, unreacted 244ca, by-products, etc., may be included in the reaction product. When recovering 1233yd from the reaction product containing these, it is preferable to employ a general separation and purification method such as distillation. Examples include separation and purification by distillation, water washing, and solid adsorption treatment by contact with a solid adsorbent. Separation from 1233yd is possible by a combination of these methods. Examples of solid adsorbents include activated carbon, zeolite, silica, alumina, etc. Two or more solid adsorbents may be used in combination. Zeolite is preferred because it has high adsorption capacity for by-products, etc. [Examples]

[0059] The present invention will be described in detail below, but the present invention is not limited to these examples. Among the methods for producing 244ca in the examples, Examples 1 to 6 are examples of liquid-phase reactions, Example 7 is an example of a gas-phase reaction, and Example 8 is an example of a method for producing 1233yd.

[0060] (Analysis conditions) In the preparation of the various compounds in the examples, the compositional analysis of the resulting reaction compositions was performed using gas chromatography (GC). The column used was DB-1301 (trade name, manufactured by Agilent Technologies, Inc., length 60 m × inner diameter 250 μm × thickness 1 μm).

[0061] (Example of 254cb production) 254cb can be produced, for example, using a reaction apparatus equipped with a U-shaped reaction tube having a catalyst layer packed with a catalyst support and a salt bath in which it is immersed, according to the method described in International Publication No. 2018 / 139654. Specifically, 244 cc was supplied together with hydrogen to palladium catalyst-supported activated carbon, in which 2.0 parts by mass of palladium was supported as a catalyst support per 100 parts by mass of activated carbon, and the reaction was carried out.

[0062] The catalyst layer, heated to 250°C by adjusting the temperature of the salt bath, was then circulated with 244cc of gas and hydrogen gas in such a total molar ratio that hydrogen / 244cc = 2 / 1. The reaction composition was then recovered from the outlet of the reaction tube. The contact time with the catalyst layer was 20 seconds, and the linear velocity u was 2 cm / second.

[0063] The recovered reaction composition contained 244cc, 263eb, 263ca, etc. 254cb was obtained from this reaction composition by distillation.

[0064] (Example 1) 244ca was produced by chlorinating the 254cb obtained in the above manufacturing example.

[0065] First, a stainless steel autoclave (2.0 liters) fitted with a quartz tube and jacket that transmit light from a light source was cooled to 20°C. 1530 g of carbon tetrachloride (CCl4) and 116 g of 254cb were placed inside this autoclave (hereinafter referred to as the reactor). Then, chlorine gas was introduced into the reactor at a flow rate of 7.1 g per hour while irradiating it with visible light of wavelengths from 200 to 750 nm using an LED lamp (Mitsubishi Electric LHT42N-G-E39, 40W output). The reaction pressure during this process was 0.0 to 0.2 MPaG. This flow rate of chlorine gas was introduced for 5 hours, meaning that 0.5 moles of chlorine were introduced for every 1 mole of 254cb.

[0066] After the reaction was complete, the resulting reaction solution was neutralized by mixing it with a 20% by mass aqueous solution of potassium bicarbonate, and then liquid-liquid separation was performed. After standing, reaction composition 1 was recovered from the separated lower layer and subjected to GC analysis.

[0067] (Example 2) The same reactor used in Example 1 was kept at 20°C, and 1530g of carbon tetrachloride (CCl4) was added as the solvent, followed by 116g of 254cb. Subsequently, chlorine gas was supplied to the reactor at a flow rate of 14.2g per hour while irradiating it with visible light with a wavelength of 200-750nm from an LED lamp (Mitsubishi Electric LHT42N-G-E39, 40W output). The reaction pressure during this process was 0.0-0.2 MPaG. The above flow rate of chlorine gas was introduced for 2.5 hours, meaning that 0.5 moles of chlorine were introduced for every 1 mole of 254cb.

[0068] After the reaction was complete, the resulting reaction solution was neutralized by mixing it with a 20% by mass aqueous solution of potassium bicarbonate, and then liquid-liquid separation was performed. After standing, reaction composition 2 was recovered from the separated lower layer and subjected to GC analysis.

[0069] (Example 3) The same reactor used in Example 1 was kept at 20°C, and 1530g of carbon tetrachloride (CCl4) and 116g of 254cb were added. Then, chlorine gas was introduced into the reactor at a flow rate of 3.6g per hour while irradiating it with visible light with a wavelength of 200-750nm from an LED lamp (Mitsubishi Electric LHT42N-G-E39, 40W output). The reaction pressure during this process was 0.0-0.2 MPaG. The above flow rate of chlorine gas was introduced for 10 hours, that is, 0.5 moles of chlorine were introduced for every 1 mole of 254cb, and the light irradiation was continued until the temperature inside the reactor remained constant at 20°C.

[0070] After the reaction was complete, the resulting reaction solution was neutralized by mixing it with a 20% by mass aqueous solution of potassium bicarbonate, and then liquid-liquid separation was performed. After standing, reaction composition 3 was recovered from the separated lower layer and subjected to GC analysis.

[0071] (Example 4) The same reactor used in Example 1 was kept at 50°C, and 1530g of carbon tetrachloride (CCl4) and 116g of 254cb were added. Then, while irradiating the reactor with visible light of wavelengths from 200 to 750nm using an LED lamp (Mitsubishi Electric LHT42N-G-E39, 40W output), chlorine gas was introduced into the reactor at a flow rate of 7.1g per hour. The reaction pressure during this process was 0.0 to 0.2 MPaG. The above flow rate of chlorine gas was introduced for 5 hours, meaning that 0.5 moles of chlorine were introduced for every 1 mole of 254cb.

[0072] After the reaction was complete, the resulting reaction solution was neutralized by mixing it with a 20% by mass aqueous solution of potassium bicarbonate, and then liquid-liquid separation was performed. After standing, reaction composition 4 was recovered from the separated lower layer and subjected to GC analysis.

[0073] (Example 5) The same reactor used in Example 1 was kept at 0°C, and 1530g of carbon tetrachloride (CCl4) and 116g of 254cb were added. Then, while irradiating the reactor with visible light of wavelengths from 200 to 750nm using an LED lamp (Mitsubishi Electric LHT42N-G-E39, 40W output), chlorine gas was introduced into the reactor at a flow rate of 7.1g per hour. The reaction pressure during this process was 0.0 to 0.2 MPaG. The above flow rate of chlorine gas was introduced for 5 hours, meaning that 0.5 moles of chlorine were introduced for every 1 mole of 254cb.

[0074] After the reaction was complete, the resulting reaction solution was neutralized by mixing it with a 20% by mass aqueous solution of potassium bicarbonate, and then liquid-liquid separation was performed. After standing, reaction composition 5 was recovered from the separated lower layer and subjected to GC analysis.

[0075] (Example 6) In Example 1, a solenoid valve was installed at the bottom of the reactor to maintain the internal temperature at 20°C, and 1530g of carbon tetrachloride (CCl4) was added. Subsequently, 254cb was introduced into the reactor at a flow rate of 11.6g per hour and chlorine gas at a flow rate of 3.6g per hour while irradiating with visible light with a wavelength of 200-750nm from an LED lamp (Mitsubishi Electric LHT42N-G-E39, 40W output). The reaction pressure during this process was 0.0-0.2 MPaG. The crude reaction liquid was withdrawn through the solenoid valve at the bottom of the reactor to maintain a constant reactor liquid level. Light irradiation was continued at the above flow rates for 10 hours.

[0076] After the reaction was complete, the resulting reaction solution was neutralized by mixing it with a 20% by mass aqueous solution of potassium bicarbonate, and then liquid-liquid separation was performed. After standing, reaction composition 6 was recovered from the separated lower layer and subjected to GC analysis.

[0077] The reaction conditions for Examples 1-6 and the GC analysis results of the obtained reaction compositions are shown in Table 1. In Table 1, the conversion rate of 254cb is the ratio of the amount of 254cb consumed in the reaction to the amount of 254cb supplied to the reactor, and is expressed in molar terms (unit: mol%). The selectivity of each compound is the ratio of each compound to the total amount of the reaction composition, and is expressed in molar terms (unit: mol%).

[0078] [Table 1]

[0079] As can be seen from Table 1, according to Examples 1-6, the target 244ca can be obtained with high selectivity.

[0080] (Example 7) A gas-phase reactor (manufactured by Swagelok) consisting of a cylindrical reaction tube made of SUS316 with an inner diameter of 21.4 mm and a length of 50 cm was filled with activated carbon as a catalyst to a height of 40 cm, and the reactor temperature was maintained at 100°C in an electric furnace. 254cb was supplied to this gas-phase reactor from a cylinder maintained at 50°C, via a mass flow controller and a preheater. The temperature in the line from the cylinder through the mass flow controller to the preheater was maintained at 50°C to prevent condensation of 254cb.

[0081] The above gas-phase reactor was supplied with chlorine / 254cb in a molar ratio of 1:1 for a contact time of 20 seconds to obtain the generated gas. GC analysis of the recovered generated gas showed that the conversion rate of 254cb was 93.2%, the selectivity for 244ca and 234cc was 80.9% and 5.9%, respectively, and the selectivity for 244cc, 234cb, 224ca, 224cb, and 214cb was 1.5%, 4.4%, 1.5%, 2.9%, and 2.9%, respectively.

[0082] (Example 8) In a 2-liter four-necked flask equipped with a stirrer and a Liebig condenser, 989.40 g of the raw material composition containing 244ca as the main component obtained in Example 6 and 9.89 g of tetra-n-butylammonium bromide (TBAB) were placed, and the flask was heated to 50°C. The reaction temperature was maintained at 50°C, and 1396.01 g of 40% by mass potassium hydroxide (KOH) aqueous solution was added dropwise over 30 minutes. Stirring was then continued for 52 hours, and the organic layer was recovered. The reaction time in this example is the sum of the time required for the dropwise addition and the time spent stirring after addition, i.e., 52.5 hours.

[0083] The collected organic layer was washed with water and analyzed using a gas chromatogram. The results are shown in Table 2.

[0084] [Table 2] [Industrial applicability]

[0085] According to the manufacturing method of the present invention, 244ca can be produced efficiently and with high purity by reacting 254cb with chlorine. The manufacturing method of the present invention is a method that can carry out large-scale reactions without using special operations or reaction equipment, and by this method, 244ca can be produced in large quantities on an industrial scale. Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-013256, filed on January 29, 2021, are incorporated herein by reference as disclosure of the specification of the present invention.

Claims

1. A method for producing 3-chloro-1,1,2,2-tetrafluoropropane, comprising reacting 1,1,2,2-tetrafluoropropane with chlorine, A method for producing 3-chloro-1,1,2,2-tetrafluoropropane, wherein the reaction temperature of the above reaction is 5 to 60°C.

2. The method for producing the product according to claim 1, wherein in the reaction of 1,1,2,2-tetrafluoropropane with chlorine, the reaction product contains 1,3-dichloro-1,1,2,2-tetrafluoropropane in an amount of 10% by mass or less relative to the total amount of 3-chloro-1,1,2,2-tetrafluoropropane and 1,3-dichloro-1,1,2,2-tetrafluoropropane.

3. The manufacturing method according to claim 1 or 2, wherein 0.01 to 3 moles of chlorine are used per mole of 1,1,2,2-tetrafluoropropane.

4. The manufacturing method according to any one of claims 1 to 3, wherein the reaction between 1,1,2,2-tetrafluoropropane and chlorine is carried out in the liquid phase.

5. The manufacturing method according to claim 4, wherein the reaction time of the above reaction is 1 second to 100 hours.

6. The manufacturing method according to claim 4 or 5, wherein the pressure of the reaction is 0.05 to 1 MPa in gauge pressure.

7. The manufacturing method according to any one of claims 4 to 6, comprising continuously supplying the 1,1,2,2-tetrafluoropropane to a reactor and continuously withdrawing the reaction product from the reactor.

8. The manufacturing method according to any one of claims 4 to 7, wherein the above reaction is carried out in the presence of a solvent.

9. The production method according to claim 8, wherein the solvent is at least one selected from the group consisting of carbon tetrachloride, 1,1,2-trichloro-1,2,2-trifluoroethane, 1-chloro-1,1,2,2-tetrafluoropropane, 1,3-dichloro-1,1,2,2-tetrafluoropropane, 1,3,3-trichloro-1,1,2,2-tetrafluoropropane, 1,3,3,3-tetrachloro-1,1,2,2-tetrafluoropropane, 3-chloro-1,1,2,2-tetrafluoropropane, 1,1-dichloro-2,2,3,3-tetrafluoropropane, 1,1,1-trichloro-2,2,3,3-tetrafluoropropane, and 1,3,3,4,4,6-hexachloro-1,1,2,2,5,5,6,6-octafluorohexane.

10. The manufacturing method according to claim 8 or 9, wherein the solvent is used in an amount of 1 to 4000% by mass relative to the mass of 1,1,2,2-tetrafluoropropane.

11. The manufacturing method according to any one of claims 1 to 3, wherein the reaction between 1,1,2,2-tetrafluoropropane and chlorine is carried out in the gas phase.

12. The manufacturing method according to claim 11, wherein the reaction time of the above reaction is 1 second to 1 hour.

13. The manufacturing method according to claim 11 or 12, wherein the pressure of the reaction is 0 to 1 MPa in gauge pressure.

14. A method for producing 1-chloro-2,3,3-trifluoropropene, characterized by reacting 1,1,2,2-tetrafluoropropane with chlorine at a reaction temperature of 5 to 60°C to obtain 3-chloro-1,1,2,2-tetrafluoropropane, and then subjecting the obtained 3-chloro-1,1,2,2-tetrafluoropropane to a dehydrofluoridation reaction in the presence of a base or catalyst.

15. The method for producing the product according to claim 14, wherein the reaction product obtained by the dehydrofluoride reaction contains 1,3-dichloro-2,3,3-trifluoropropene in an amount of 10% by mass or less relative to the 1-chloro-2,3,3-trifluoropropene.

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