Process for producing 3-chloro-1,1,2,2-tetrafluoropropane and process for producing 1-chloro-2,3,3-trifluoropropene

Abstract

A high-purity, efficient 244ca manufacturing method is provided. A method for manufacturing 3-chloro-1,1,2,2-tetrafluoropropane, in which 1,1,2,2-tetrafluoropropane is reacted with chlorine to obtain 3-chloro-1,1,2,2-tetrafluoropropane.

Description

Technical Field

[0001] This invention relates to a method for manufacturing 3-chloro-1,1,2,2-tetrafluoropropane and a method for manufacturing 1-chloro-2,3,3-trifluoropropene. Background Technology

[0002] 3-Chloro-1,1,2,2-Tetrafluoropropane (CHF2-CF2-CH2Cl, HCFC-244ca, hereinafter also referred to as 244ca) is used as a novel detergent, refrigerant, foaming agent, solvent and aerosol or as a raw material for their synthesis.

[0003] For example, Patent Document 1 describes 244ca as a synthetic raw material for the manufacture of 1-chloro-2,3,3-trifluoropropene (CHF2-CF=CHCl, HCFO-1233yd, hereinafter also referred to as 1233yd).

[0004] As a method for manufacturing 244ca, Patent Document 2 describes a method for manufacturing 244ca by reacting 2,2,3,3-tetrafluoropropanol (hereinafter also referred to as TFPO) as a synthetic raw material with thionyl chloride as a chlorinating agent in the presence of N,N-dimethylformamide.

[0005] Existing technical documents

[0006] Patent documents

[0007] [Patent Document 1] Japanese Patent No. 6132042

[0008] [Patent Document 2] International Publication No. 2018 / 131394 Summary of the Invention

[0009] The technical problem that the invention aims to solve

[0010] The 244ca manufacturing method described in Patent Document 2 uses thionyl chloride as a chlorinating agent, so the reaction products contain hydrogen chloride or sulfur dioxide as byproducts. Therefore, a large amount of alkaline aqueous solution must be used for neutralization. As a result, a 244ca manufacturing method suitable for large-scale industrial production is still under research.

[0011] The purpose of this invention is to provide an industrially advantageous method for manufacturing high-purity 244ca.

[0012] means of solving technical problems

[0013] In order to solve the above-mentioned technical problems, the inventors conducted in-depth research and found that the above-mentioned technical problems can be solved by the following configuration.

[0014] [1] A method for producing 3-chloro-1,1,2,2-tetrafluoropropane, wherein 1,1,2,2-tetrafluoropropane is reacted with chlorine to obtain 3-chloro-1,1,2,2-tetrafluoropropane.

[0015] [2] The manufacturing method as described in [1], wherein, in the reaction of the 1,1,2,2-tetrafluoropropane with the chlorine, the content of 1,3-dichloro-1,1,2,2-tetrafluoropropane in the reaction product is less than 10% by mass relative to the total amount of the 3-chloro-1,1,2,2-tetrafluoropropane and the 1,3-dichloro-1,1,2,2-tetrafluoropropane.

[0016] [3] The manufacturing method as described in [1] or [2], wherein 0.01 to 3 moles of the chlorine are used relative to 1 mole of the 1,1,2,2-tetrafluoropropane.

[0017] [4] The manufacturing method as described in any one of [1] to [3], wherein the reaction of the 1,1,2,2-tetrafluoropropane with the chlorine is carried out in the liquid phase.

[0018] [5] The manufacturing method as described in [4], wherein the reaction temperature of the reaction is -20 to 100°C.

[0019] [6] The manufacturing method as described in [4] or [5], wherein the reaction time is from 1 second to 100 hours.

[0020] [7] The manufacturing method as described in any one of [4] to [6], wherein the pressure of the reaction is 0 to 1 MPa as measured by a gauge pressure gauge.

[0021] [8] The manufacturing method as described in any one of [4] to [7], wherein the 1,1,2,2-tetrafluoropropane is continuously supplied to the reactor and the reaction products are continuously extracted from the reactor.

[0022] [9] The manufacturing method as described in any one of [4] to [8], wherein the reaction is carried out in the presence of a solvent.

[0023]

[10] The manufacturing method as described in [9], wherein the solvent is selected from at least one 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.

[0024]

[11] The manufacturing method as described in [9] or

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

[0025]

[12] The manufacturing method according to any one of claims [1] to [3], wherein the reaction of the 1,1,2,2-tetrafluoropropane with the chlorine is carried out in the gas phase.

[0026]

[13] The manufacturing method as described in

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

[0027]

[14] The manufacturing method as described in

[12] or

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

[0028]

[15] The manufacturing method as described in any one of

[12] to

[14] , wherein the pressure of the reaction is 0 to 1 MPa as measured by a gauge pressure gauge.

[0029]

[16] A method for manufacturing 1-chloro-2,3,3-trifluoropropene, wherein 3-chloro-1,1,2,2-tetrafluoropropane obtained by any one of the manufacturing methods of claims [1] to

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

[0030]

[17] The manufacturing method as described in

[16] , wherein the content of 1,3-dichloro-2,3,3-trifluoropropene in the reaction product obtained by the dehydrofluorination reaction is less than 10% by mass relative to the 1-chloro-2,3,3-trifluoropropene.

[0031] The effects of the invention

[0032] According to the present invention, a method for manufacturing high-purity and high-efficiency 244ca can be provided. Detailed Implementation

[0033] In this specification, compound names are sometimes referred to by the abbreviation shown in parentheses following the compound name.

[0034] In this specification, chlorine refers to chlorine in its molecular state (Cl2). Pressure refers to gauge pressure unless otherwise specified.

[0035] In the presence of isomers of a compound, unless otherwise specified, it indicates a mixture of one or more of those isomers. For example, in the presence of both a Z isomer and an E isomer, it signifies only the Z isomer, only the E isomer, or any mixture of the 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 compound. For example, 1233yd(Z) indicates the Z isomer, and 1233yd(E) indicates the E isomer.

[0036] The method for manufacturing 244ca of the present invention (hereinafter referred to as "the manufacturing method of 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 for obtaining 244ca from the chlorination reaction of 254cb is the reaction shown in the following formula (1) (hereinafter also referred to as reaction (1)).

[0037]

Chemistry 1

[0038]

[0039] Surprisingly, the manufacturing method of the present invention has the advantage of selectively obtaining 244ca in the chlorination reaction of 254cb with almost no other chlorides produced.

[0040] Hereinafter, the components used in the manufacturing method of the present invention will be described in detail first, and the steps of the manufacturing method will be described in detail.

[0041] (Manufacturing method of 254cb)

[0042] In the manufacturing method of this invention, 254cb is used as a raw material. 254cb is a compound known as a raw material or intermediate in the manufacture of fluorinated compounds.

[0043] There are no particular restrictions on the method for obtaining 254cb, and known methods described in International Publication No. 2018 / 139654, etc., can be cited as examples. Specifically, it can be produced by reacting 1-chloro-1,1,2,2-tetrafluoropropane (CClF2-CF2-CH3, HCFC-244cc, hereinafter also referred to as 244cc) with hydrogen in the presence of a catalyst at a temperature exceeding 200°C.

[0044] In the above reaction in which 244cc is reduced by reacting with hydrogen, a hydrogenation catalyst is used. A palladium catalyst is preferred as the hydrogenation catalyst. The palladium catalyst can be not only elemental palladium, but also a catalyst composed of palladium, or a palladium-containing metal catalyst. As a palladium-containing metal catalyst, a palladium alloy catalyst is preferred. Examples of palladium alloy catalysts include palladium / platinum alloy catalysts and palladium / rhodium alloy catalysts. Furthermore, a mixture of palladium-containing metal catalysts and other metals can also be used as the palladium catalyst.

[0045] Alternatively, a catalyst formed by supporting the above-mentioned palladium catalyst on a support (hereinafter also referred to as a palladium supported catalyst) can be used, or a composite catalyst formed by supporting the above-mentioned palladium catalyst and other metals on a support respectively can be used.

[0046] Examples of suitable supports for palladium-supported catalysts include activated carbon and metal oxides (alumina, zirconium oxide, silica, etc.). Activated carbon is preferred from the perspectives of activity, durability, and reaction selectivity. Examples of activated carbons include those derived from plant materials (wood, charcoal, fruit shells, coconut shells, etc.) and mineral materials (peat, coal, coal, etc.). From the perspective of catalyst durability, activated carbon derived from plant materials is preferred, with coconut shell activated carbon being particularly preferred.

[0047] The reduction reaction of 244cc with hydrogen is preferably carried out in the gas phase. Specifically, this is achieved by filling a reaction tube with a catalyst support to form a catalyst layer, and then allowing 244cc of gas and hydrogen to flow through this catalyst layer. The temperature of the catalyst layer during the reaction is above 200°C, preferably 210–350°C, and more preferably 250–300°C. The ratio of 244cc to hydrogen is adjusted appropriately. Alternatively, a dilution gas composed of nitrogen, rare gases, etc., can be added to the 244cc gas and hydrogen to facilitate the reaction.

[0048] 254cb can be separated from the reaction product obtained by the reaction of 244cc with hydrogen using conventional separation methods, such as distillation, and can be used as a raw material for the manufacturing method of the present invention.

[0049] The raw material 254cb in the manufacturing method of the present invention can also be a mixture of other compounds. That is, the raw material in the manufacturing method of the present invention only needs to contain 254cb, for example, a mixture of 254cb and other compounds can also be used as a raw material.

[0050] Other compounds that may be contained in the raw materials suitable for the manufacturing method of the present invention include impurities such as raw materials for manufacturing 254cb or by-products other than 254cb generated during the manufacturing of 254cb. Furthermore, if the raw materials contain the aforementioned impurities, the by-products generated from the impurities can be removed by known methods such as distillation, extractive distillation, azeotropic distillation, membrane separation, double-layer separation, and adsorption. As impurities, inert compounds are preferred in the manufacturing method of the present invention.

[0051] The raw materials used in the chlorination reaction preferably contain 254cb as a major 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. As an upper limit, 100% by mass can be cited as an example.

[0052] (Manufacturing method)

[0053] In the manufacturing method of this invention, 254cb is contacted with chlorine in a reactor to produce 244ca through a chlorination reaction. 254cb obtained by the above method can be used as the starting material. However, the method for obtaining 254cb is not limited to this. The manufacturing method of this invention can also be carried out in either the liquid phase or the gas phase; from an industrial perspective, a liquid phase reaction is preferred.

[0054] Here, in the chlorination reaction of 254cb, a side reaction occurs, producing as byproducts 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-CHC). Chlorides such as l2, HCFC-224ca (hereinafter also called 224ca), 1,3,3,3-tetrachloro-1,1,2,2-tetrafluoropropane (CClF2-CF2-CCl3, HCFC-214cb, hereinafter also called 214cb), 1,1,1-trichloro-2,2,3,3-tetrafluoropropane (CHF2-CF2-CCl3, HCFC-224cb, hereinafter also called 224cb), and 1,3,3,4,4,6-hexachloro-1,1,2,2,5,5,6,6-octafluorohexane.

[0055] Chlorides other than 244ca, which are generated as byproducts in the chlorination reaction of 254cb, can be used to produce the target product 244ca or the raw material 254cb through a hydrogen reduction reaction. For example, if 244cc is generated as a byproduct in the manufacturing method of the present invention, 254cb can be produced and reused as a raw material by reacting 244cc with hydrogen in the presence of a catalyst. Furthermore, if 234cc or 234cb is generated as a byproduct in the manufacturing method of the present invention, 244ca can be produced by reacting 234cc or 234cb with hydrogen in the presence of a catalyst.

[0056] In the chlorination reaction of 254cb in the manufacturing method of the present invention, in order to improve the selectivity of 244ca, it is preferable to carry out the reaction under conditions that suppress the above-mentioned side reactions.

[0057] The product 244ca from the manufacturing method of this invention is a compound that can be used as a raw material for manufacturing 1233yd. 1233yd is a compound that can be used in various applications as a detergent, refrigerant, foaming agent, solvent, or aerosol. When the raw material containing 244ca contains 234cc, byproducts are generated, which may lead to a decrease in the selectivity of 1233yd. Therefore, the 234cc content relative to the raw material containing 244ca is preferred. Thus, the chlorination reaction of 254cb is preferably carried out under conditions where the amount of 234cc generated relative to the total amount of reaction products is reduced.

[0058] In the manufacturing method of the present invention, when the reaction product contains 234cc, the content of 234cc relative to the total amount of 244ca and 234cc in the reaction product is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 3% by mass or less, and particularly preferably 1% by mass or less. Within the above range, the formation of by-products during the manufacturing of 1233yd can be suppressed.

[0059] The shape and structure of the reactor are not particularly limited, as long as it can allow the reaction of 254cb and chlorine to proceed. Examples of such reactors include glass reactors, SUS reactors, glass-lined reactors, and resin-lined reactors. The reactor typically has a temperature control unit to regulate the internal temperature. This temperature control unit only needs to be able to adjust the reaction temperature between 254cb and chlorine. Examples of such a structure include oil baths. Alternatively, the temperature control unit can be integrated into the reactor.

[0060] The manufacturing method of this invention can be carried out in either the liquid phase or the gas phase. From an industrial perspective, it is preferred to carry out the reaction in the liquid phase. A gas-phase reaction refers to the reaction of gaseous 254cb with gaseous chlorine, while a liquid-phase reaction refers to the reaction of liquid 254cb with gaseous chlorine.

[0061] The reaction conditions in the liquid phase of the manufacturing method of the present invention will be described in detail below, followed by a detailed description of the reaction conditions in the gas phase.

[0062] (Regarding chlorination reactions carried out in the liquid phase)

[0063] As a specific means of liquid-phase reaction, an example is the process of supplying liquid 254cb and gaseous chlorine into a reactor, and then contacting the 254cb with the chlorine in the reactor to obtain 244ca. Furthermore, this reaction is preferably carried out under light irradiation.

[0064] In the manufacturing method of the present invention, from the perspective of activating the reaction, suppressing the generation of by-products, and improving the selectivity and yield of 244ca, 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 of chlorine (Cl2) relative to 1 mole of 254cb, more preferably 0.1 to 2 moles, further preferably 0.2 to 1.6 moles, and most preferably 0.5 to 1.5 moles.

[0065] In the manufacturing method of the present invention, the reaction temperature (temperature inside the reactor) is preferably -20 to 100°C when carried out in the liquid phase, and more preferably 5 to 60°C. Within the above-mentioned range, the reaction can be activated and the formation of by-products can be suppressed.

[0066] In the case of a liquid-phase reaction, the chlorination reaction can be carried out using any of the following methods: semi-continuous, batch, or continuous. The reaction time can be any time commonly used in each method and can be adjusted appropriately according to 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 254 cb and chlorine in the reactor. The raw materials can be supplied to the reactor by supplying each component separately, or by supplying a mixture of the components, or by a combination of these methods. When chlorine is supplied to the reactor in the form of chlorine gas, the chlorine gas can be diluted with an inert gas such as nitrogen as needed. When the manufacturing method of the present invention is carried out continuously, the reaction time is the residence time of 254 cb and chlorine in the reactor.

[0067] In the case of a semi-continuous chlorination reaction, the raw materials are preferably supplied to the reaction system individually or as a mixture of the components at a certain rate. The supply of raw materials can be intermittent or continuous.

[0068] In the case of a batch chlorination reaction, the raw materials are preferably fed into the reactor along with the solvent before the reaction.

[0069] In the case of a continuous chlorination reaction, the raw materials are continuously supplied and the reaction products are continuously withdrawn. For example, a preferred method is to continuously supply the raw materials to the reaction system from the bottom of the reactor where the solvent has been added and to continuously withdraw the reaction products from the top of the reactor (overflow method, etc.). From the perspective of improving the selectivity of 244ca and suppressing the generation of 234cc, the manufacturing method of the present invention preferably carries out the reaction continuously.

[0070] In the case of a continuous chlorination reaction, it is preferable to supply the raw material and extract the product in such a way that the raw material 254cb and chlorine are retained in the reactor for 1 second to 100 hours, and the retention time is more preferably 1 second to 50 hours, and particularly preferably 1 second to 10 hours.

[0071] In chlorination reactions carried out in the liquid phase, any of the semi-continuous, batch, or continuous methods can be used with conventional methods and apparatus, and the reaction is preferably carried out while stirring.

[0072] The reaction pressure in the manufacturing method of this invention is equivalent to the pressure inside the reactor. For more efficient manufacturing, the pressure inside the reactor is preferably 0–1 MPa, more preferably 0.05–0.5 MPa. To improve productivity, the reaction is preferably carried out under pressure.

[0073] From the perspective of improving the reaction rate, the manufacturing method of the present invention is preferably carried out under light irradiation. The wavelength of the irradiation light is preferably 200-750 nm, more preferably 250-730 nm. Using light with a wavelength above 200 nm can effectively suppress the formation of by-products, while using light with a wavelength below 750 nm allows the reaction to proceed fully. In addition, the irradiation light may also include light with a wavelength less than 200 nm or light with a wavelength greater than 750 nm.

[0074] Among light sources capable of efficiently irradiating light with wavelengths from 200 to 750 nm, examples include fluorescent lamps, LED lamps, incandescent lamps, high-pressure mercury lamps, and halogen lamps. Light sources that generate significant heat are not preferred because they make it difficult to maintain a low internal temperature within the reactor. High internal temperatures lead to increased internal pressure, necessitating improvements in the reactor's pressure resistance, which is costly. Furthermore, high internal temperatures increase the likelihood of side reactions. Fluorescent lamps or LED lamps are preferred as light sources that generate minimal heat.

[0075] The light irradiation method can be any method that can uniformly irradiate the entire reaction system, including the raw materials containing 254cb and chlorine, the solvents mentioned above as needed, and the products containing 244ca, over the reaction time, without any particular limitations.

[0076] Specific methods of light irradiation include inserting a light source with a protective sheath into the reaction solution, or irradiating the raw materials in the reaction solution with light from inside the reaction solution. The protective sheath is preferably made of a material that transmits light at least at wavelengths useful for the reaction, is inert to the components contained in the reaction solution, and is not easily corroded by these components. Furthermore, when the light source generates heat, the protective sheath is preferably equipped with a cooling mechanism depending on the reaction temperature.

[0077] When the manufacturing method of the present invention is carried out in the liquid phase, 254cb and chlorine can be supplied to the reactor separately, or they can be supplied in a pre-mixed state.

[0078] When the manufacturing method of the present invention is carried out in the liquid phase, a solvent can be used. Preferably, the solvent is one that can dissolve the raw material components containing 254cb and chlorine, is inert to the raw material components, and can be easily separated from the target product containing 244ca by distillation or the like.

[0079] Examples of solvents include carbon tetrachloride and 1,1,2-trichloro-1,2,2-trifluoroethane. Additionally, 244ca can be used as a solvent, as can 244cc, 234cc, 224ca, 214cb, 234cb, 224cb, and 1,3,3,4,4,6-hexachloro-1,1,2,2,5,5,6,6-octafluorohexane, which are produced as byproducts. These compounds can be used alone or in combination.

[0080] The preferred solvents are carbon tetrachloride, which is low in cost and easy to separate from the target product, and 244ca, which does not require separation.

[0081] The amount of solvent used is not particularly limited as long as it can dissolve the generated 244ca. It is preferably 1 to 4000% by mass relative to the raw material 254cb, and more preferably 50 to 3000% by mass.

[0082] (Regarding chlorination carried out by gas-phase reaction)

[0083] As a specific step in a gas-phase reaction, an example is the process of supplying gaseous 254cb and gaseous chlorine to the reactor, and then bringing the gaseous 254cb into contact with the chlorine in the reactor to obtain 244ca.

[0084] From the perspective of effectively regulating flow rate, suppressing byproducts, and inhibiting catalyst deactivation, a gas that is inert to the above reaction (dilution gas) can also be supplied to the reactor. Specific examples of dilution gases include nitrogen, carbon dioxide, helium, and argon.

[0085] In the manufacturing method of the present invention, from the perspective of activating the reaction, suppressing the generation of by-products, and improving the selectivity and yield of 244ca, 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 of chlorine (Cl2) relative to 1 mole of 254cb, more preferably 0.1 to 2 moles, further preferably 0.2 to 1.6 moles, and most preferably 0.5 to 1.5 moles.

[0086] In the case of chlorination in the gas phase, from the perspective 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 perspective of improving 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.

[0087] The reaction products obtained by chlorination reactions in liquid phase or gas phase include the target product 244ca, unreacted raw materials, solvent, chlorides of non-target products, and other byproducts.

[0088] As a method for separating the target product 244ca from products containing 244ca, conventional separation methods can be used, such as removing chlorine by washing with alkali and then removing the solvent and byproducts by distillation. Alternatively, 244ca can be purified to a higher purity by distillation, and the desired purity of 244ca can be obtained by repeated distillation.

[0089] In the manufacturing method of the present invention, when the reaction product after the separation step contains 234cc, the content of 234cc relative to the total amount of 244ca and 234cc in the reaction product is preferably 10% by mass or less, more preferably 5% by mass or less, further preferably 3% by mass or less, and particularly preferably 1% by mass or less. Within the above range, the formation of by-products during the manufacturing of 1233yd is suppressed.

[0090] Furthermore, when separating 244ca by distillation, if components with boiling points lower than 244ca form an azeotropic or pseudo-azeotropic composition with water, 244ca can be recovered in a water-free state by distilling water together with the low-boiling-point components. Specific examples of components with boiling points lower than 244ca include 244cc, 254cb, fluoromethane, difluoromethane, 1,1,1,2-tetrafluoroethane, fluoroethane, 1,2-difluoroethane, and 1233yd(E).

[0091] (The creation of 1233yd)

[0092] 244ca is a compound that can be used as a raw material for the manufacture of 1233yd. 1233yd is a compound that can be used in various applications as a detergent, refrigerant, foaming agent, solvent, or aerosol. 1233yd can be manufactured by subjecting 244ca to a dehydrofluorination reaction. An example method for manufacturing 1233yd is to subject 244ca obtained by the method of this invention to a dehydrofluorination reaction in the presence of either a base or a catalyst.

[0093] As a step in the defluorination reaction, known methods such as International Publication No. 2016 / 136744 can be cited as examples.

[0094] Examples of bases used in the defluorination reaction of 244ca include metal hydroxides, metal oxides, or metal carbonates. From the perspective of reaction time and yield, metal hydroxides are preferred, and potassium hydroxide or sodium hydroxide are particularly preferred. Examples of catalysts used in the defluorination reaction of 244ca include quaternary ammonium salts, quaternary phosphonium salts, quaternary thionium salts, sulfonium salts, crown ethers, etc. Quaternary ammonium salts are preferred, and tetrabutylammonium chloride (TBAC), tetrabutylammonium bromide (TBAB), and methyltri-n-octylammonium chloride (TOMAC) are particularly preferred.

[0095] The dehydrofluorination reaction of 244ca can be carried out in either the liquid phase or the gas phase. A liquid phase reaction refers to the dehydrofluorination of 244ca in liquid or dissolved form. A gas phase reaction refers to the dehydrofluorination of gaseous 244ca.

[0096] The 1233yd produced using 244ca obtained by the manufacturing method of this invention has high purity and low content of byproducts such as 1,3-dichloro-2,3,3-trifluoropropene (CClF2-CF=CHCl, HCFO-1223yd, hereinafter also referred to as 1223yd), and therefore can be used for various purposes.

[0097] Especially when using reactants containing 244ca with a low 234cc content to produce 1233yd, the purification process for 1233yd can be simplified by reducing the byproduct yield of 1223yd, which is also economically advantageous. 1223yd is an azeotropic compound with 1233yd, making it difficult to separate from 1233yd by distillation. However, the above method allows for the industrially viable supply of 1233yd with a purity of over 90%.

[0098] 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, further preferably 3% by mass or less, particularly preferably 1% by mass or less, and most preferably 0.5% by mass or less.

[0099] In the manufacturing method of this invention, in addition to the target product 1233yd, unreacted 244ca, byproducts, etc., are also included in the reaction products. When recovering 1233yd from the reaction products containing these substances, a separation and purification method such as conventional distillation is preferred. Examples of separation and purification methods such as distillation, or water washing treatment with water, or solid adsorption treatment by contacting a solid adsorbent, are possible. A combination of these treatments can also be used to separate 1233yd. Examples of solid adsorbents include activated carbon, zeolite, silica, and alumina. Two or more solid adsorbents can be used in combination. Zeolite is preferred because it has high adsorption capacity for byproducts, etc.

[0100] Example

[0101] The present invention will now be described in detail, but the present invention is not limited to these embodiments. In the 244ca manufacturing method of the embodiments, Examples 1 to 6 are examples of liquid-phase reaction, Example 7 is an example of gas-phase reaction, and Example 8 is an example of 1233yd manufacturing method.

[0102] (Analysis conditions)

[0103] 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 chromatographic column used was a DB-1301 (trade name, manufactured by Agilent Technologies, 60 m long × 250 μm inner diameter × 1 μm thick).

[0104] (Example of manufacturing 254cb)

[0105] 254 cb can be manufactured, for example, using a reaction apparatus comprising a U-shaped reaction tube having a catalyst layer filled with a catalyst support and a salt bath for impregnating the reaction tube, according to the method described in International Publication No. 2018 / 139654. Specifically, 244 cb is supplied together with hydrogen to palladium catalyst-supported activated carbon to cause it to react, wherein the palladium loading in the palladium catalyst-supported activated carbon is 2.0 parts by mass relative to 100 parts by mass of activated carbon used as a catalyst support.

[0106] In a catalyst bed heated to 250°C in an regulated salt bath, 244cc of gas and hydrogen are circulated at a total molar ratio of hydrogen / 244cc = 2 / 1. The reaction composition is recovered from the outlet of the reaction tube. The contact time with the catalyst bed is 20 seconds, and the linear velocity u is 2 cm / s.

[0107] The recovered reaction composition contained 244cc, 263eb, 263ca, etc. 254cb was obtained from this reaction composition by distillation.

[0108] (Example 1)

[0109] 244ca is produced by chlorinating the 254cb obtained in the above manufacturing example.

[0110] First, a stainless steel autoclave (internal volume 2.0 liters) equipped with a quartz tube and sheath that transmits light through a light source was cooled to 20°C. Then, 1530 g of carbon tetrachloride (CCl4) and 116 g of 254cb were added to the autoclave (hereinafter referred to as the reactor). Chlorine gas was introduced into the reactor at a flow rate of 7.1 g per hour while irradiating it with visible light (200–750 nm wavelength) emitted by an LED lamp (Mitsubishi Electric Corporation LHT42N-G-E39, 40W output power). The reaction was carried out at a pressure of 0.0–0.2 MPaG. Chlorine gas was introduced at the above flow rate for 5 hours, resulting in the introduction of chlorine at a ratio of 0.5 moles to 1 mole of 254cb.

[0111] After the reaction was complete, the resulting reaction solution was neutralized by mixing with a 20% (w / w) aqueous solution of potassium bicarbonate, followed by separation. After settling, reaction composition 1 was recovered from the lower layer and subjected to GC analysis.

[0112] (Example 2)

[0113] A reactor identical to that used in Example 1 was maintained at 20°C, and 1530 g of carbon tetrachloride (CCl4) and 116 g of 254 cb were added to the reactor as solvent. Then, while irradiating the reactor with visible light (200–750 nm wavelength) emitted by an LED lamp (Mitsubishi Electric Corporation LHT42N-G-E39, 40 W output power), chlorine gas was introduced into the reactor at a flow rate of 14.2 g per hour. The reaction pressure was maintained at 0.0–0.2 MPaG. Chlorine gas was introduced at the above flow rate for 2.5 hours, meaning that chlorine was introduced in a ratio of 0.5 moles to 1 mole of 254 cb.

[0114] After the reaction was complete, the resulting reaction solution was neutralized by mixing with a 20% (w / w) aqueous solution of potassium bicarbonate, followed by separation. After settling, reaction composition 2 was recovered from the lower layer and subjected to GC analysis.

[0115] (Example 3)

[0116] A reactor identical to that used in Example 1 was maintained at 20°C. 1530 g of carbon tetrachloride (CCl4) and 116 g of 254 cb were introduced into the reactor. Chlorine gas was introduced into the reactor at a flow rate of 3.6 g per hour while irradiating it with visible light (200–750 nm wavelength) emitted by an LED lamp (Mitsubishi Electric Corporation LHT42N-G-E39, 40 W output power). The reaction was carried out at a pressure of 0.0–0.2 MPaG. Chlorine gas was introduced at the above flow rate for 10 hours, i.e., chlorine was introduced in a ratio of 0.5 moles to 1 mole of 254 cb, and irradiation continued until the temperature inside the reactor remained constant at 20°C.

[0117] After the reaction was complete, the resulting reaction solution was neutralized by mixing with a 20% (w / w) aqueous solution of potassium bicarbonate, followed by separation. After settling, reaction composition 3 was recovered from the lower layer and subjected to GC analysis.

[0118] (Example 4)

[0119] A reactor identical to that used in Example 1 was maintained at 50°C. 1530 g of carbon tetrachloride (CCl4) and 116 g of 254 cb were added. Chlorine gas was introduced into the reactor at a flow rate of 7.1 g per hour while irradiating it with visible light (200–750 nm) emitted by an LED lamp (Mitsubishi Electric Corporation LHT42N-G-E39, 40 W output). The reaction was carried out at a pressure of 0.0–0.2 MPaG. Chlorine gas was introduced at the above flow rate for 5 hours, resulting in the introduction of chlorine at a ratio of 0.5 moles per mole of 254 cb.

[0120] After the reaction was complete, the resulting reaction solution was neutralized by mixing with a 20% (w / w) aqueous solution of potassium bicarbonate, followed by separation. After settling, reaction composition 4 was recovered from the lower layer and subjected to GC analysis.

[0121] (Example 5)

[0122] A reactor identical to that used in Example 1 was maintained at 0°C. 1530 g of carbon tetrachloride (CCl4) and 116 g of 254 cb were added. Chlorine gas was introduced into the reactor at a flow rate of 7.1 g per hour while irradiating it with visible light (200–750 nm wavelength) emitted by an LED lamp (Mitsubishi Electric Corporation LHT42N-G-E39, 40 W output). The reaction was carried out at a pressure of 0.0–0.2 MPaG. Chlorine gas was introduced at the above flow rate for 5 hours, resulting in the introduction of chlorine at a ratio of 0.5 moles per mole of 254 cb.

[0123] After the reaction was complete, the resulting reaction solution was neutralized by mixing with a 20% (w / w) aqueous solution of potassium bicarbonate, followed by separation. After settling, reaction composition 5 was recovered from the lower layer and subjected to GC analysis.

[0124] (Example 6)

[0125] A reactor identical to that used in Example 1 was maintained at 20°C, and 1530 g of carbon tetrachloride (CCl4) was added to it. Then, while irradiating the reactor with visible light (200–750 nm wavelength) emitted by an LED lamp (Mitsubishi Electric Corporation LHT42N-G-E39, 40 W output power), 254 cb of chlorine gas was introduced into the reactor at a flow rate of 11.6 g / h, and chlorine gas at a flow rate of 3.6 g / h. The reaction pressure was maintained at 0.0–0.2 MPaG. The crude reaction liquid was withdrawn through a solenoid valve located at the bottom of the reactor to maintain a constant liquid level. Irradiation was continued at the above flow rates for 10 hours.

[0126] After the reaction was complete, the resulting reaction solution was neutralized by mixing with a 20% (w / w) aqueous solution of potassium bicarbonate, followed by separation. After settling, reaction composition 6 was recovered from the lower layer and subjected to GC analysis.

[0127] The reaction conditions and GC analysis results of the resulting reaction compositions in Examples 1-6 are shown in Table 1.

[0128] 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, expressed as a molar conversion (in mol%). Additionally, the selectivity of each compound is the ratio of that compound to the total amount of the reaction mixture, expressed as a molar conversion (in mol%).

[0129] Table 1

[0130]

[0131] As shown in Table 1, according to Examples 1-6, the target 244ca can be obtained with a high selectivity.

[0132] (Example 7)

[0133] In a gas-phase reactor (manufactured by Swaglok Corporation) consisting of a cylindrical reaction tube made of SUS316 steel with an inner diameter of 21.4 mm and a length of 50 cm, activated carbon as a catalyst is filled to a height of 40 cm, and the reactor temperature is maintained at 100°C using an electric furnace. 254cb is supplied to the gas-phase reactor from a cylinder maintained at 50°C via a mass flow controller and a preheater. To prevent 254cb condensation, the temperature of the pipeline from the cylinder to the preheater via the mass flow controller is maintained at 50°C.

[0134] The gas-phase reactor was fed with a contact time of 20 seconds and a chlorine / 254cb molar ratio of 1:1 to obtain the product gas. GC analysis of the recovered product gas showed a 254cb conversion rate of 93.2%, selectivities of 244ca and 234cc of 80.9% and 5.9%, respectively, and selectivities of 244cc, 234cb, 224ca, 224cb, and 214cb of 1.5%, 4.4%, 1.5%, 2.9%, and 2.9%, respectively.

[0135] (Example 8)

[0136] 989.40 g of the raw material composition containing 244ca obtained in Example 6 above as the main component and 9.89 g of tetrabutylammonium bromide (TBAB) were added to a 2-liter four-necked flask equipped with a stirrer and a Dimro cooler. The flask was heated to 50°C. The reaction temperature was maintained at 50°C, and 1396.01 g of a 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 total time required for the dropwise addition and the subsequent stirring time, which is 52.5 hours.

[0137] The recovered organic layer was washed with water, and the results obtained by gas chromatography analysis are shown in Table 2.

[0138] Table 2

[0139]

[0140] Industrial availability

[0141] According to the manufacturing method of the present invention, 254cb can be reacted with chlorine to produce 244ca with high purity and high efficiency. The manufacturing method of the present invention is a method that does not employ special operating procedures or reaction equipment and can carry out large-scale reactions, thereby enabling the mass production of 244ca on an industrial scale.

[0142] Furthermore, the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2021-013256, filed on January 29, 2021, are hereby incorporated as a disclosure of this invention.

Claims

1. A method for producing 3-chloro-1,1,2,2-tetrafluoropropane, wherein, 1,1,2,2-Tetrafluoropropane is reacted with chlorine to give 3-chloro-1,1,2,2-tetrafluoropropane. The reaction is carried out in the liquid phase at a reaction temperature of 5–60 °C and a pressure of 0.05–0.5 MPa (gauge pressure), or in the gas phase at a reaction temperature of 50–200 °C.

2. The manufacturing method as described in claim 1, wherein, In the reaction of 1,1,2,2-tetrafluoropropane with chlorine, the content of 1,3-dichloro-1,1,2,2-tetrafluoropropane in the reaction product is less than 10% by mass 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 as described in claim 1 or 2, wherein, 0.01 to 3 moles of chlorine are used relative to 1 mole of the 1,1,2,2-tetrafluoropropane.

4. The manufacturing method as described in claim 1, wherein, The reaction time of the liquid phase reaction is from 1 second to 100 hours.

5. The manufacturing method as described in claim 1, wherein, The 1,1,2,2-tetrafluoropropane is continuously supplied to the reactor, and the reaction products are continuously extracted from the reactor.

6. The manufacturing method as described in claim 1, wherein, The liquid-phase reaction is carried out in the presence of a solvent.

7. The manufacturing method as described in claim 6, wherein, The solvent is selected from at least one 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.

8. The manufacturing method as described in claim 6 or 7, wherein, The amount of solvent used is 1 to 4000 by mass relative to the mass of the 1,1,2,2-tetrafluoropropane.

9. The manufacturing method as described in claim 1, wherein, The reaction time of the gas phase reaction is from 1 second to 1 hour.

10. The manufacturing method as claimed in claim 1, wherein, The pressure of the gas phase reaction is 0-1 MPa as measured by a gauge manometer.

11. A method for manufacturing 1-chloro-2,3,3-trifluoropropylene, wherein, 3-Chloro-1,1,2,2-Tetrafluoropropane is obtained by the manufacturing method according to any one of claims 1 to 10, and then subjected to a dehydrofluorination reaction in the presence of a base or catalyst.

12. The manufacturing method as described in claim 11, wherein, In the reaction product obtained by the dehydrofluorination reaction, the content of 1,3-dichloro-2,3,3-trifluoropropene is less than 10% by mass relative to the 1-chloro-2,3,3-trifluoropropene.

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