Method for producing 1,1,2-trifluoroethane, and composition

Abstract

This method for producing 1,1,2-trifluoroethane involves causing a raw material containing 1,1,2-trifluoroethylene but effectively not containing chlorotrifluoroethylene to undergo a reduction reaction with a reducing agent at a reaction temperature of 100°C or higher to obtain 1,1,2-trifluoroethane.

Description

Method for producing 1,1,2-trifluoroethane and composition

[0001] This disclosure relates to a method for producing 1,1,2-trifluoroethane and to compositions thereof.

[0002] 1,1,2-trifluoroethane (HFC-143) is a useful substance because it is a raw material for trans-1,2-difluoroethylene (HFO-1132(E)), a low global warming potential (GWP) refrigerant. For example, Patent Document 1 describes 1,1,2-trifluoroethylene (HFO-1123, CF) under temperature conditions of 200-300°C. ２ A method for producing HFC-143 is described, which involves reducing CHF with a reducing agent to obtain 1,1,2-trifluoroethane (HFC-143).

[0003] Patent No. 7260803

[0004] However, in the manufacturing method described in Patent Document 1, along with the target product HFC-143, 1-chloro-1,1-difluoroethane (HCFC-142b, CClFHCFH) is used. ２ ), 1-chloro-1,1,2-trifluoroethane (HCFC-133b, CClF ２ CFH ２ ), and 1,2-dichloro-1,1,2-trifluoroethane (HCFC-123a, CClF ２ It was found that CClFH) is produced as a by-product. These compounds have boiling points close to HFC-143 and form azeotropic or azeotropic-like compositions, making them difficult to separate by purification.

[0005] Furthermore, in the reaction scheme to obtain HFC-143 by reducing HFO-1123, 1,1,1,2-tetrafluoroethane (HFC-134a, CF ３ CH ２ F) may be produced as a by-product. HFC-134a has a remarkably high GWP of 1430.

[0006] Therefore, the object of one embodiment of the present disclosure is to provide a method for producing HFC-143 in which HCFC-142b, HCFC-133b, and HCFC-123a, which form an azeotrope or azeotrope-like composition with the target product HFC-143, and HFC-134a, which has a high GWP, are not substantially produced as by-products, and to provide a composition obtained by this method.

[0007] This disclosure includes the following aspects: <1> A method for producing 1,1,2-trifluoroethane, comprising reducing a raw material containing 1,1,2-trifluoroethylene and substantially free of chlorotrifluoroethylene with a reducing agent at a reaction temperature of 100°C or higher to obtain 1,1,2-trifluoroethane. <2> The method for producing 1,1,2-trifluoroethane according to <1>, wherein the external control temperature for achieving the reaction temperature is 100°C or lower. <3> The method for producing 1,1,2-trifluoroethane according to <2>, wherein the temperature difference between the reaction temperature and the external control temperature is 80°C or higher. <4> The method for producing 1,1,2-trifluoroethane according to any one of <1> to <3>, wherein the reaction temperature is 250°C or lower. <5> The method for producing 1,1,2-trifluoroethane according to any one of <1> to <4>, wherein 0.5 to 30 moles of the reducing agent are used per mole of 1,1,2-trifluoroethylene. <6> The method for producing 1,1,2-trifluoroethane according to any one of <1> to <5>, wherein the reduction reaction is carried out in the presence of a catalyst. <7> The method for producing 1,1,2-trifluoroethane according to <6>, wherein the residence time of 1,1,2-trifluoroethylene in the catalyst is 0.5 to 40 seconds. <8> The method for producing 1,1,2-trifluoroethane according to <6> or <7>, wherein 1,1,2-trifluoroethylene and a reducing agent are circulated through the catalyst packed in a fixed-bed reactor, and the movement of the reaction area toward the outlet side is substantially suppressed. <9> The method for producing 1,1,2-trifluoroethane according to any one of <1> to <8>, wherein the water content relative to the total amount of 1,1,2-trifluoroethylene and the reducing agent is 1 mol% or less. <10> A method for producing 1,1,2-trifluoroethylene according to any one of <1> to <9>, wherein the 1,1,2-trifluoroethylene is derived from at least one selected from the group consisting of 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, and tetrafluoroethylene.<11> A composition comprising 1,1,2-trifluoroethane and at least one additional compound selected from the group consisting of 1,1-difluoroethane, monofluoroethane, and ethane, substantially free of 1,1,1,2-tetrafluoroethane, 1-chloro-1,1-difluoroethane, 1-chloro-1,1,2-trifluoroethane, and 1,2-dichloro-1,1,2-trifluoroethane, wherein the total amount of the additional compound is 10 mol% or less relative to 1,1,2-trifluoroethane. <12> The composition according to <11>, wherein the total amount of the additional compound is 0.01 mol% or more relative to 1,1,2-trifluoroethane. <13> The composition according to <11> or <12>, wherein the additional compound comprises 1,1-difluoroethane, monofluoroethane, and ethane. <14> The composition according to <11> or <12>, further comprising 1,1,2-trifluoroethylene. <15> The composition according to any one of <11> to <14>, wherein the content of 1,1,2-trifluoroethane is 80 mol% or more.

[0008] According to this disclosure, a method for producing HFC-143 in which HCFC-142b, HCFC-133b, and HCFC-123a, which form an azeotrope or azeotrope-like composition with the target product HFC-143, and HFC-134a, which has a high GWP, are not substantially produced as by-products, and a composition obtained by this production method is provided. In addition, "not substantially producing HCFC-142b, HCFC-133b, HCFC-123a, and HFC-134a as by-products" means that the total amount of HCFC-142b, HCFC-133b, HCFC-123a, and HFC-134a in the obtained composition is 300 mol ppm or less.

[0009] In the present disclosure, a numerical range indicated using "~" means a range that includes the numerical values described before and after "~" as the minimum value and the maximum value, respectively. In a numerical range described stepwise in the present disclosure, the upper limit or lower limit described in one numerical range may be replaced with the upper limit or lower limit of another stepwise described numerical range. Further, in the numerical range described in the present disclosure, the upper limit or lower limit described in a certain numerical range may be replaced with the value shown in the examples. In the present disclosure, a combination of two or more preferred embodiments is a more preferred embodiment. In the present disclosure, when a plurality of types of substances corresponding to each component are present, the amount of each component means the total amount of the plurality of types of substances unless otherwise specified. In the present disclosure, an azeotropic composition means a composition that has no difference between the composition of the liquid phase and the vapor phase under a constant pressure and behaves as if it were a single substance. In the present disclosure, an azeotrope-like composition means a composition that, in a composition capable of forming an azeotropic composition, has a composition approximate to the azeotropic composition and exhibits behavior close to that of an azeotropic composition. The azeotrope-like composition can be distilled and / or refluxed with almost no change in composition. Therefore, the azeotrope-like composition can be handled substantially the same as an azeotropic composition. One of the characteristics of the azeotrope-like composition is that the difference in pressure between the boiling point curve and the dew point curve in a pressure-composition diagram is within 5%.

[0010] <Method for producing HFC-143> The method for producing HFC-143 according to the present disclosure comprises, at a reaction temperature of 100°C or higher, 1,1,2-trifluoroethylene (HFO-1123, CF ２ =CHF) and substantially free of chlorotrifluoroethylene (CTFE, CClF=CF ２ ) is subjected to a reduction reaction with a reducing agent to obtain 1,1,2-trifluoroethane (HFC-143, CHF ２ CH ２ F).

[0011] In this disclosure, "reaction temperature" refers to the highest temperature within the reaction region, and is also referred to as the "hot spot temperature" below. The reaction region is a region that is hotter than other regions (or, in the case of a catalyst layer, the region of the other catalyst layer) due to the generation of reaction heat. The "hot spot" refers to the region that exhibits the highest temperature within the reaction region.

[0012] The general reaction scheme for obtaining HFC-143 from HFO-1123 is as follows:

[0013]

[0014] In Patent Document 1, since the raw material compound HFO-1123 is synthesized from CTFE (chlorotrifluoroethylene), it is assumed that HCFC-142b, HCFC-133b, and HCFC-123a are produced as by-products along with the target product HFC-143. Since CTFE remains in the HFO-1123 derived from CTFE, and the HFO-1123 containing CTFE, which is a chlorine-containing compound, is reduced by a reducing agent, it is thought that chlorine-containing compounds such as HCFC-142b, HCFC-133b, and HCFC-123a are produced as by-products. In this disclosure, since 1,1,2-trifluoroethylene that is substantially free of CTFE is used as the raw material, HCFC-142b, HCFC-133b, and HCFC-123a are not substantially produced as by-products.

[0015] The boiling points of the target product HFC-143, as well as HCFC-142b, HCFC-133b, and HCFC-123a, are as follows, and these compounds form azeotropic compositions or azeotropic-like compositions with HFC-143.

[0016]

[0017] Furthermore, it was experimentally discovered that by using raw materials containing HFO-1123 and substantially free of CTFE, and carrying out a reduction reaction with a reducing agent at a reaction temperature of 100°C or higher, HFC-134a, which has a high GWP, is substantially not produced as a by-product.

[0018] The method for producing HFC-143 according to this disclosure will be described in detail below. It is preferable that the method for producing HFC-143 according to this disclosure be carried out in the gas phase. Carrying the process in the gas phase offers advantages over liquid-phase reactions in terms of recovering products and unreacted raw materials, and, if a catalyst is used, in terms of separating the catalyst from the product. Therefore, hereafter, the gas containing 1,1,2-trifluoroethylene and a reducing agent will also be referred to as the raw material gas.

[0019] (Raw Materials) The method for producing HFC-143 according to this disclosure uses raw materials that contain HFO-1123 and substantially do not contain CTFE. The CTFE content in the raw materials is preferably 1000 mol ppm or less, more preferably 500 mol ppm or less, even more preferably 100 mol ppm or less, particularly preferably 50 mol ppm or less, and particularly preferably below the detection limit. The raw materials may contain other components besides HFO-1123 and CTFE. The raw materials may consist only of HFO-1123, or they may contain isomers, disproportionation products, impurities, etc. obtained when producing HFO-1123.

[0020] HFO-1123 is 1,1,1,2-tetrafluoroethane (HFC-134a, CF ３ CH ２ F), 1,1,2,2-tetrafluoroethane (HFC-134, CHF ２ CHF ２ ) and tetrafluoroethylene (TFE, CF ２ =CF ２ It is preferable that it is derived from at least one selected from the group consisting of ). HFO-1123 can be produced by a de-HF reaction from HFC-134 or HFC-134a. The method of the de-HF reaction is not limited, but examples include the method using aluminum oxide as shown in Japanese Patent No. 6780656. Furthermore, since HFC-134 is a hydrogenated reduced product of tetrafluoroethylene (TFE), HFC-134 can be produced by a reduction reaction in which TFE is brought into contact with hydrogen, and then HFO-1123 can be produced from this HFC-134 by a de-HF reaction. Since HFC-134a, HFC-134, and TFE are compounds that do not contain chlorine atoms, the inclusion of chlorine-containing compounds as impurities in HFO-1123 is suppressed.

[0021] The chlorine-containing compound content in the raw material is preferably 1,000 mol ppm or less, more preferably 500 mol ppm or less, even more preferably 100 mol ppm or less, particularly preferably 50 mol ppm or less, and most preferably below the detection limit.

[0022] Furthermore, if chlorine-containing compounds are present as impurities in the raw materials, they can affect the catalyst, as described below, potentially leading to catalyst degradation. For example, when palladium is used as a catalyst, chlorine atoms can form palladium chloride, rendering the catalyst inactive in the hydrogen reduction reaction. Therefore, if chlorine-containing compounds are present as impurities in the raw materials, the amount of work required to remove the degraded catalyst and replace it with a new one increases, reducing manufacturing efficiency. Additionally, as the catalyst degrades due to chlorine-containing compounds, its temperature gradually decreases, further reducing the reaction rate. In contrast, HFO-1123, derived from at least one selected from the group consisting of HFC-134a, HFC-134, and TFE, minimizes the inclusion of chlorine-containing compounds as impurities, thus suppressing catalyst degradation.

[0023] Furthermore, in the method for producing HFC-143 described herein, since raw materials that substantially do not contain CTFE are used, the inclusion of chlorine-containing compounds as impurities is suppressed, making it possible to suppress catalyst degradation.

[0024] Furthermore, in the case of reduction reactions using a fixed-bed reactor, as described later, a catalyst is packed into the fixed-bed reactor to form a catalyst layer, through which 1,1,2-trifluoroethylene and a reducing agent are passed. In this case, the raw material gas containing HFO-1123 usually reacts in a portion of the catalyst layer, and the reaction region becomes hotter than other regions of the catalyst layer due to the generation of reaction heat. When the catalyst deteriorates, the reaction region usually gradually moves downstream from the raw material gas inlet in the direction of gas flow. Also, downstream of the reaction region, the high-temperature product gas generated in the reaction region flows, and is usually hotter than the temperature of the catalyst layer, with the temperature gradually decreasing as you move away from the reaction region.

[0025] In the initial stages of reactor operation, the catalyst near the inlet of the raw material gas contributes to the reaction. As the reactor continues to operate and the catalyst deteriorates, the catalyst further towards the outlet of the raw material gas contributes to the reaction. Thus, as the reactor continues to operate, the reaction zone in the catalyst layer gradually shifts from the inlet side of the raw material gas to the outlet side.

[0026] However, in the method for producing HFC-143 of this disclosure, since a raw material substantially free of CTFE is used, catalyst degradation is suppressed, the movement of the reaction region toward the outlet is substantially suppressed, and the decrease in reaction rate can be suppressed over the long term. Furthermore, if HFO-1123 derived from at least one selected from the group consisting of HFC-134a, HFC-134, and TFE is used, catalyst degradation is suppressed, the movement of the reaction region toward the outlet is substantially suppressed, and the decrease in reaction rate can be suppressed over the long term.

[0027] Here, "substantially suppressed movement of the reaction region toward the outlet" means that the movement speed of the reaction region toward the outlet is 50 mm / hr or less, preferably 30 mm / hr or less, more preferably 20 mm / hr or less, and even more preferably 10 mm / hr or less. The movement speed of the reaction region toward the outlet may be adjusted by the flow rate of the raw material gas, the size of the reactor filled with catalyst, etc.

[0028] From the viewpoint of suppressing catalyst degradation, the content of HFO-1123 relative to the total amount of raw materials is preferably 85 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, particularly preferably 99 mol% or more, and may also be 100 mol%. There is no particular upper limit on the content of HFO-1123 relative to the total amount of raw materials.

[0029] While a higher HFO-1123 content in the raw material is preferable, from the viewpoint of increasing the purification cost of HFO-1123 and making process control difficult, it may be 99 mol% or less, or even 95 mol% or less.

[0030] (Reducing Agent) Any reducing agent capable of adding hydrogen to HFC-143 through a reduction reaction may be used, and either inorganic or organic reducing agents may be used. Specifically, examples include hydrogen, formic acid, ammonium formate, sodium formate, potassium formate, isopropyl alcohol, formic acid-triethylamine, triethylsilane, tetramethyldisiloxane, polymethylhydrosiloxane, NaBH ３ CN, NHCBH ３ (N-heterocyclic carbenes boranes), and nitrogen-containing unsaturated heterocyclic compounds having an N-H moiety (imino group). Among these, hydrogen, hydrogen sulfide, methane, and the like can be used as the reducing agent for carrying out a gas-phase reduction reaction in the presence of a catalyst, and hydrogen is preferably used because it can efficiently add hydrogen to HFO-1123.

[0031] The amount of the reducing agent used is preferably 0.5 to 30 moles per 1 mole of HFO-1123. When hydrogen is used as the reducing agent, the amount thereof is preferably 0.5 to 20 moles, more preferably 1.0 to 10 moles, of hydrogen per 1 mole of HFO-1123. When other reducing agents are used, the amount of the reducing agent is preferably 0.5 to 30 moles, more preferably 1.0 to 20 moles, per 1 mole of HFO-1123. By adopting such a configuration, the inclusion of a sufficient amount of the reducing agent suppresses deterioration of the catalyst, and HFC-143, which is the target product, can be obtained with high selectivity. In addition, since the amount of the reducing agent is not excessive, the effect of reducing product loss associated with the recovery of unreacted hydrogen can be obtained.

[0032] (Catalyst) The method for producing HFC-143 of the present disclosure is preferably carried out in the presence of a catalyst. As the catalyst, known reduction catalysts can be widely used, and there is no particular limitation. A palladium catalyst is preferable as the catalyst. The palladium catalyst is preferably used after being supported on a carrier. The palladium catalyst may be not only simple substance palladium but also a palladium alloy. Alternatively, it may be a catalyst supporting a mixture of palladium and another metal, or a composite catalyst in which palladium and another metal are separately supported on a carrier. Examples of the palladium alloy catalyst include a palladium / platinum alloy catalyst, a palladium / rhodium alloy catalyst, and the like.

[0033] Preferable catalysts include those in which only palladium or a palladium alloy is supported on a carrier, or those in which palladium and a metal other than palladium are supported on a carrier. A catalyst in which palladium and a metal other than palladium are supported on a carrier tends to have higher catalyst durability than a catalyst in which only palladium is supported on a carrier. Examples of metals other than palladium include Group 8 elements (iron, ruthenium, osmium, etc.), Group 9 elements (cobalt, rhodium, iridium, etc.), Group 10 elements (nickel, platinum, etc.), and gold. One of these other metals may be used alone, or two or more thereof may be used in combination. The proportion of the other metal is preferably 0.01 to 50 parts by mass relative to 100 parts by mass of palladium.

[0034] Examples of the carrier include activated carbon, metal oxides (alumina, zirconia, silica, etc.), and the like. Activated carbon is preferable from the viewpoints of activity, durability, and reaction selectivity. Examples of activated carbon include those obtained from plant raw materials (wood, charcoal, fruit shells, coconut shells, etc.), mineral raw materials (peat, lignite, coal, etc.), and the like. From the viewpoint of catalyst durability, those obtained from plant raw materials are preferable, and coconut shell activated carbon is particularly preferable. Examples of the shape of activated carbon include formed charcoal with a length of about 2 to 10 mm, crushed charcoal of about 4 to 50 mesh, granular charcoal, and the like. From the viewpoint of activity, 4 to 20 mesh crushed charcoal or formed charcoal with a length of 2 to 5 mm is preferable.

[0035] The amount of palladium supported is preferably 0.1 to 10 parts by mass, and more preferably 0.5 to 1 part by mass, per 100 parts by mass of activated carbon. If the amount of palladium supported is 0.1 parts by mass or more, the reaction rate between the raw material compound HFO-1123 and the reducing agent is improved. If the amount of palladium supported is 10 parts by mass or less, it is easier to suppress excessive temperature rise in the catalyst layer due to reaction heat and reduce the generation of by-products. For carriers other than activated carbon, the amount of palladium supported is preferably the same as that for activated carbon.

[0036] (Dilution Gas) The method for producing HFC-143 according to this disclosure may be carried out in the presence of a dilution gas. The dilution gas is preferably at least one selected from the group consisting of nitrogen, hydrogen, carbon dioxide, helium, propane, isobutane, n-butane, ethane, propylene, and fluorinated methane. Examples of fluorinated methane include monofluoromethane, difluoromethane, and trifluoromethane. The molar ratio of HFO-1123 to the dilution gas in the gas phase is preferably 0.1 to 5.0, more preferably 0.5 to 3.0, and even more preferably 0.5 to 2.0.

[0037] (Reaction Conditions) The reactor used to carry out the reduction reaction of HFO-1123 with a reducing agent can be any reactor capable of withstanding the temperature and pressure described later, and its shape and structure are not particularly limited. Examples of reactors include cylindrical vertical reactors and U-shaped reactors. Examples of reactor materials include glass, stainless steel, iron, nickel, and alloys mainly composed of iron or nickel. The reactor may be equipped with heating means such as an electric heater to heat the inside of the reactor.

[0038] The catalyst may be contained in a fixed-bed, fluidized-bed, or moving-bed configuration. If it is a fixed-bed configuration, it may be either a horizontal or vertical fixed-bed configuration. The reaction configuration may be a flow-through or batch configuration.

[0039] In fixed-bed reactors, various molded catalyst supports are packed to reduce pressure loss of the reaction fluid. A moving-bed reactor is another method where the catalyst is packed similarly to a fixed-bed reactor, moved by gravity, and then extracted from the bottom of the reactor for regeneration. In fluidized-bed reactors, the catalyst is suspended in the reaction fluid and moves within the reactor, as the catalyst layer behaves like a fluid due to the reaction fluid. Fixed-bed reactors are preferred because they offer a wide range of catalyst shapes and suppress catalyst wear. Fixed-bed reactors include tubular reactors and tank reactors, with tubular reactors preferred due to their ease of controlling the reaction temperature. Furthermore, multi-tube heat exchange reactions, where numerous small-diameter reaction tubes are arranged in parallel and a heat transfer medium is circulated around them, can be employed. When multiple reactors are arranged in series, multiple catalyst layers are provided. At least one catalyst layer is sufficient, but two or more layers are also possible.

[0040] From the viewpoint of improving the reaction rate, the method for producing HFC-143 according to this disclosure is preferably carried out in a flow-through manner using a fixed-bed reactor (particularly a vertical fixed-bed reactor).

[0041] A catalyst layer is formed within a fixed-bed reactor by filling it with a catalyst support. When a catalyst support is used as the catalyst, the packing density of the catalyst support in the catalyst layer is 0.5 to 1 g / cm³. ３ Preferably, 0.6 to 0.8 g / cm³ ３ This is more preferable. The packing density of the catalyst support is 0.5 g / cm³. ３ If the above conditions are met, the amount of catalyst support packed per unit volume can be increased, and the amount of gas reacted can be increased, thus improving productivity. The packing density of the catalyst support is 1 g / cm³. ３ The following conditions make it easier to suppress excessive temperature rise in the catalyst layer due to reaction heat and reduce the generation of by-products. There may be one or more packed portions of catalyst support in the reactor.

[0042] From the viewpoint of obtaining the effects of this disclosure, the method for producing HFC-143 of this disclosure is preferably carried out at a reaction temperature of 100°C or higher, more preferably at 110°C or higher, more preferably at 120°C or higher, and even more preferably at 150°C or higher. Furthermore, from the viewpoint of preventing catalyst sintering, the method for producing HFC-143 of this disclosure is preferably carried out at a reaction temperature of 250°C or lower, more preferably at 230°C or lower, even more preferably at 220°C or lower, and particularly preferably at 200°C or lower. The reaction temperature can be measured using a thermocouple or the like. The reaction range can also be confirmed using a thermocouple or the like.

[0043] When using a temperature control device such as a bath to control the reaction temperature, the external control temperature (bath temperature in the case of a bath) is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 85°C or lower. Setting the external control temperature within the above range makes it easier to control the reaction temperature from becoming too high. From the viewpoint of reaction efficiency, the external control temperature is preferably 50°C or higher, more preferably 60°C or higher, even more preferably 70°C or higher, and particularly preferably 80°C or higher.

[0044] From the viewpoint of reaction efficiency, the temperature difference between the reaction temperature and the external control temperature is preferably 80°C or higher, more preferably 85°C or higher, even more preferably 90°C or higher, and particularly preferably 100°C or higher. Furthermore, from the viewpoint of reaction control, the temperature difference between the reaction temperature and the external control temperature is preferably within 200°C, more preferably within 180°C, even more preferably within 150°C, and particularly preferably within 120°C.

[0045] In addition to controlling the reaction temperature using temperature control devices such as a bath, it may also be controlled by changing the flow rate of the raw material gas.

[0046] The pressure during the reduction reaction of HFO-1123 is not particularly limited, but from the viewpoint of improving the reaction rate, -0.05 to 2 MPa is preferred, -0.01 to 1 MPa is more preferred, and room temperature to 0.5 MPa is even more preferred. In this disclosure, pressure means gauge pressure.

[0047] The residence time of HFO-1123 in the catalyst is preferably 0.5 to 47 seconds, more preferably 0.5 to 45 seconds, even more preferably 0.5 to 40 seconds, particularly preferably 1.0 to 30 seconds, and most preferably 1.5 to 20 seconds.

[0048] The residence time (seconds) is calculated using the following formula: Residence time (seconds) = [Length of the reactor filled with catalyst (cm)] / [Linear velocity (cm / second)] Linear velocity refers to the rate at which HFO-1123 passes through the catalyst layer per unit time.

[0049] The linear velocity u of HFO-1123 in the catalyst layer varies depending on the diameter of the reaction tube, but for reaction tube diameters commonly used in gas-phase reduction reactions, it is preferably 0.1 to 100 cm / second, and more preferably 1 to 30 cm / second. The linear velocity u is the linear velocity of HFO-1123 calculated from the volume of HFO-1123 introduced into the reactor and the volume of the catalyst layer. If the linear velocity u of HFO-1123 is above the lower limit, productivity improves. In particular, if the gas linear velocity is 1 cm / second or higher, HFO-1123 flows more uniformly through the catalyst layer. If the linear velocity u of HFO-1123 is below the upper limit, the reaction rate between HFO-1123 and hydrogen gas improves. In particular, if the gas linear velocity is 30 cm / second or lower, temperature control near the reaction point due to exothermic reaction becomes easier. u = (W / 100) × V / S (I) where W is the concentration (mol%) of HFO-1123 in the total gas flowing through the catalyst layer, and V is the flow rate (cm³) of the total gas flowing through the catalyst layer. ３ ( / second) is shown, and S is the cross-sectional area (cm²) of the catalyst layer with respect to the gas flow direction. ２ ) indicates.

[0050] From the viewpoint of maintaining the reactivity of the catalyst, it is preferable that the water content in the total amount of raw materials and reducing agent, which constitute the raw material gas, be 1 mol% or less. A common method for measuring the water content is to use a dew point meter. By having a water content of 1 mol% or less relative to the total amount of raw material gas, the reaction rate is increased and the target product can be obtained with high selectivity. The water content in the total amount of raw material gas is preferably 0.5 mol% or less, more preferably 0.3 mol% or less, even more preferably 0.2 mol% or less, and particularly preferably 0.1 mol% or less, from the viewpoint of the cost of dehydration treatment of HFO-1123 and the reducing agent, and the difficulty of process control, it may be as low as the detection limit, or 0.05 mol% or more.

[0051] The water content mentioned above refers to the water content in the raw material gas when HFO-1123 is reacted with the reducing agent. Alternatively, the water content may be replaced with the water content in the raw material gas before it enters the reactor.

[0052] Compounds other than the raw material compound (HFO-1123) and the target product (HFC-143) contained in the reactor outlet gas include, for example, 1,1-difluoroethane (HFC-152a), monofluoroethane (HFC-161), ethane (R-170) (hereinafter also referred to as "additional compounds"), carbon monoxide, carbon dioxide, water, etc. Since additional compounds have lower boiling points than the target product HFC-143, it is preferable that these compounds are not included in the reactor outlet gas as much as possible. If the reactor outlet gas contains additional compounds with lower boiling points than HFC-143, attempting to remove the additional compounds by purification will also remove the target product HFC-143, resulting in poor production efficiency. For the composition of the reactor outlet gas, etc., refer to the composition of the composition described later.

[0053] According to the method for producing HFC-143 of this disclosure, since HCFC-142b, HCFC-133b, and HCFC-123a, which form azeotropic compositions or azeotropic-like compositions with HFC-143, are not substantially produced as by-products, the reactor outlet gas purification step can be omitted, and HFC-143 can be obtained efficiently. Furthermore, the method for producing HFC-143 of this disclosure has the advantage of suppressing catalyst degradation because chlorine-containing compounds such as HCFC-142b, HCFC-133b, and HCFC-123a are not substantially produced as by-products. Moreover, since HFC-134a, which has a high GWP, is not substantially produced as a by-product of the method for producing HFC-143 of this disclosure, the obtained reactor outlet gas is useful as a raw material for refrigerants.

[0054] <Composition> The composition of the present disclosure comprises 1,1,2-trifluoroethane (HFC-143) and at least one additional compound selected from the group consisting of 1,1-difluoroethane (HFC-152a), monofluoroethane (HFC-161), and ethane (R-170), and substantially does not contain 1,1,1,2-tetrafluoroethane (HFC-134a), 1-chloro-1,1-difluoroethane (HCFC-142b), 1-chloro-1,1,2-trifluoroethane (HCFC-133b), and 1,2-dichloro-1,1,2-trifluoroethane (HCFC-123a), and the total amount of the additional compound is 10 mol% or less relative to 1,1,2-trifluoroethane (HFC-143).

[0055] The compositions of this disclosure may be obtained by the method for producing HFC-143 of this disclosure as described above. The compositions of this disclosure are substantially free of HCFC-142b, HCFC-133b, and HCFC-123a, which form azeotropic compositions or azeotropic-like compositions with HFC-143. Since the compositions of this disclosure are substantially free of chlorine-containing compounds HCFC-142b, HCFC-133b, and HCFC-123a, substantially no hydrogen chloride is generated in the reaction, thus reducing corrosion of reaction tubes and storage containers. Furthermore, since the compositions of this disclosure are substantially free of HFC-134a, which has a high GWP, they are useful as raw materials for refrigerants.

[0056] Furthermore, "substantially free of HFC-134a, HCFC-142b, HCFC-133b, and HCFC-123a" means that the total amount of HFC-134a, HCFC-142b, HCFC-133b, and HCFC-123a in the composition is 1000 mol ppm or less, preferably 700 mol ppm or less, more preferably 500 mol ppm or less, even more preferably 100 mol ppm or less, and particularly preferably below the detection limit of the analytical instrument.

[0057] The additional compounds are compounds with a boiling point lower than HFC-143, but since the total amount of additional compounds in the composition is 10 mol% or less relative to HFC-143, even when the composition is purified to remove the additional compounds, the target product HFC-143 is less likely to be removed by droplet entrainment. The total amount of additional compounds is preferably 8 mol% or less relative to HFC-143, more preferably 6 mol% or less, even more preferably 5 mol% or less, and particularly preferably 4 mol% or less. Furthermore, the total amount of additional compounds is preferably 0.01 mol% or more relative to HFC-143, more preferably 0.1 mol% or more, and even more preferably 1 mol% or more. When the total amount of additional compounds is 0.01 mol% or more relative to HFC-143, the amount of HFC-143 entrained by droplets during the purification of the composition tends to decrease, and the manufacturing load also tends to decrease.

[0058] The additional compounds may include HFC-152a, HFC-161, and R-170. Even if the additional compounds include HFC-152a, HFC-161, and R-170, the total amount of the additional compounds in the composition of this disclosure is 10 mol% or less relative to HFC-143, so even if the composition is purified, the amount of HFC-143 entrained in droplets can be kept low.

[0059] The composition of this disclosure may further contain HFO-1123 as a raw material. The content of HFO-1123 in the composition is preferably 50 mol% or less, more preferably 30 mol% or less, even more preferably 10 mol% or less, particularly preferably 5 mol% or less, and most preferably 1 mol% or less. The content of HFO-1123 in the composition may also be 1 mol% or more, 10 mol% or more, or 20 mol% or more. The HFO-1123 contained in the composition of this disclosure can be recovered and further used as a raw material for the method of producing HFC-143 of this disclosure.

[0060] The composition of this disclosure preferably contains 80 mol% or more of the target product HFC-143, more preferably 85 mol% or more, even more preferably 90 mol% or more, and particularly preferably 95 mol% or more. Furthermore, from the viewpoint of reaction efficiency, the content of HFC-143 in the composition may be 99 mol% or less.

[0061] The present disclosure will be further described below with reference to examples, but the present disclosure is not limited to the following examples unless it exceeds the spirit of the disclosure. Example 1 is an example, and Examples 2 to 4 are comparative examples.

[0062] (Outlet Gas Composition) Thirty minutes after the start of the reaction, the product gas (hereinafter also referred to as "reactor outlet gas") extracted from the outlet of the reactor was analyzed using a gas chromatograph and a gas chromatograph-mass spectrometer. The molar composition was determined by converting the area ratio (GCAare%) of the reactor outlet gas based on the relative sensitivity of gas chromatography, so that the sum of the components listed in the table equaled 100 mol%. Specifically, the analysis was performed using a gas chromatograph (product name "GC6850", manufactured by Agilent) with a column (product name "DB-1", manufactured by Agilent, length 60 m, inner diameter 0.25 mm, film thickness 1 μm) attached. Furthermore, a column (product name "DB-1," manufactured by Agilent, 60 m in length, 0.25 mm in inner diameter, 1 μm in film thickness) was attached to the gas chromatograph of a gas chromatograph-mass spectrometer (gas chromatograph: product name "GC7890A," manufactured by Agilent, and mass spectrometer: product name "5975C"), and the ionization mode of the mass spectrometer was set to electron ionization (EI) for analysis.

[0063] (Residence Time) The residence time (seconds) above was calculated using the following formula: Residence time (seconds) = [Length of the reactor filled with catalyst (cm)] / [Linear velocity (cm / second)] Here, the linear velocity is the rate at which HFO-1123 passes through the catalyst layer per unit time.

[0064] [Example 1] (Production of HFO-1123) HFO-1123 was prepared by a de-HF reaction from HFC-134a.

[0065] (Reduction reaction of HFO-1123) 65 g of activated carbon catalyst supported with 0.5 mass% of Pd was packed into a stainless steel (SUS304) reaction tube with an inner diameter of 2.16 cm and a length of 40 cm, and placed in a bath set at a temperature of 80°C. A mixed gas of HFO-1123:hydrogen = 1:2 (molar basis) was flowed at atmospheric pressure at a mass flow controller at 414 mL / min to carry out the reduction reaction of HFO-1123. The residence time was 14.5 seconds. The temperature of the hot spot was 192°C.

[0066] [Example 2] The reduction reaction of HFO-1123 was carried out under the same conditions as in Example 1, except that the bus setting temperature was changed to 56°C and the flow rate was changed to 128 mL / min using a mass flow controller. The residence time was 47 seconds. The hot spot temperature was 97°C.

[0067] [Example 3] The reduction reaction of HFO-1123 was carried out under the same conditions as in Example 1, except that the bus setting temperature was changed to 57°C and the flow rate was changed to 130 mL / min using a mass flow controller. The residence time was 46 seconds. The hot spot temperature was 62°C.

[0068]

[0069] In Table 2, "-" means that it was not detected.

[0070] In Examples 1 to 3, HFO-1123 derived from HFC-134a was used as the raw material, and therefore, chlorine-containing compounds such as HCFC-142b, HCFC-133b, and HCFC-123a were not detected in the reactor outlet gas. As shown in Table 2, in Example 1, where the hot spot temperature was 100°C or higher, HFC-134a was not detected in the reactor outlet gas. On the other hand, in Examples 2 and 3, where the hot spot temperature was below 100°C, HFC-134a was detected in the reactor outlet gas.

[0071] [Example 4] In Example 1, the 65 g of activated carbon catalyst used was replaced with 109 g of Pd / C, and a mixed gas of HFO-1123:hydrogen = 1:2 (molar basis) was flowed through the reaction tube at 200 mL / min and 600 mL / min using a mass flow controller to change the ratio of CTFE:hydrogen to 1:3 (molar basis). The temperature of the hot spot reached 114°C. Subsequently, the mixture was flowed through a reaction tube containing 108 g of Pd / C with a bath setting temperature of 80°C. The temperature of the hot spot reached 87°C, and analysis of the outlet gas by GCMS confirmed that various HCFCs, including the target product HFC-143 and the reaction intermediate HFO-1123, as well as HCFC-142b and HCFC-123a, were produced.

[0072] The disclosure of Japanese Patent Application No. 2025-056898 is incorporated in its entirety by reference. All documents, patent applications, and technical standards in this disclosure are incorporated by reference to the same extent as if each individual document, patent application, and technical standard had been specifically and individually noted as being incorporated by reference.

Claims

1. A method for producing 1,1,2-trifluoroethane, comprising reducing a raw material containing 1,1,2-trifluoroethylene and substantially free of chlorotrifluoroethylene with a reducing agent at a reaction temperature of 100°C or higher.

2. The method for producing 1,1,2-trifluoroethane according to claim 1, wherein the external control temperature for achieving the reaction temperature is 100°C or less.

3. The method for producing 1,1,2-trifluoroethane according to claim 2, wherein the temperature difference between the reaction temperature and the externally controlled temperature is 80°C or more.

4. The method for producing 1,1,2-trifluoroethane according to claim 1 or 2, wherein the reaction temperature is 250°C or lower.

5. A method for producing 1,1,2-trifluoroethane according to claim 1 or 2, wherein 0.5 to 30 moles of the reducing agent are used per mole of 1,1,2-trifluoroethylene.

6. The method for producing 1,1,2-trifluoroethane according to claim 1 or 2, wherein the reduction reaction is carried out in the presence of a catalyst.

7. The method for producing 1,1,2-trifluoroethane according to claim 6, wherein the residence time of 1,1,2-trifluoroethylene in the catalyst is 0.5 to 40 seconds.

8. A method for producing 1,1,2-trifluoroethane according to claim 6, wherein 1,1,2-trifluoroethylene and a reducing agent are passed through the catalyst packed in a fixed-bed reactor, and the movement of the reaction region toward the outlet side is substantially suppressed.

9. A method for producing 1,1,2-trifluoroethane according to claim 1 or 2, wherein the water content relative to the total amount of 1,1,2-trifluoroethylene and the reducing agent is 1 mol% or less.

10. The method for producing 1,1,2-trifluoroethylene according to claim 1 or 2, wherein 1,1,2-trifluoroethylene is derived from at least one selected from the group consisting of 1,1,1,2-tetrafluoroethane, 1,1,2,2-tetrafluoroethane, and tetrafluoroethylene.

11. A composition comprising 1,1,2-trifluoroethane and at least one additional compound selected from the group consisting of 1,1-difluoroethane, monofluoroethane, and ethane, substantially free of 1,1,1,2-tetrafluoroethane, 1-chloro-1,1-difluoroethane, 1-chloro-1,1,2-trifluoroethane, and 1,2-dichloro-1,1,2-trifluoroethane, wherein the total amount of the additional compound is 10 mol% or less relative to 1,1,2-trifluoroethane.

12. The composition according to claim 11, wherein the total amount of the additional compounds is 0.01 mol% or more relative to 1,1,2-trifluoroethane.

13. The composition according to claim 11 or 12, wherein the additional compound comprises 1,1-difluoroethane, monofluoroethane, and ethane.

14. The composition according to claim 11 or 12, further comprising 1,1,2-trifluoroethylene.

15. The composition according to claim 11 or 12, wherein the content of 1,1,2-trifluoroethane is 80 mol% or more.

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