Method for producing chlorotrifluoroethylene and trifluoroethylene

Abstract

Provided is a method for producing chlorotrifluoroethylene and trifluoroethylene by bringing a raw material composition containing 1,1,2-trichloro-1,2,2-trifluoroethane, hydrogen, and water into contact with a catalyst, the composition having a water content of 200 ppm by mass or less with respect to the entire raw material composition, to produce chlorotrifluoroethylene and trifluoroethylene through a reaction between the 1,1,2-trichloro-1,2,2-trifluoroethane and hydrogen.

Description

Method for producing chlorotrifluoroethylene and trifluoroethylene

[0001] The present disclosure relates to a process for producing chlorotrifluoroethylene and trifluoroethylene.

[0002] Chlorotrifluoroethylene is being considered for use as a monomer for various polymers, a precursor to trifluoroethylene, and the like. Trifluoroethylene has a low global warming potential and a low boiling point, and is expected to be a type of high-pressure refrigerant. Hereinafter, chlorotrifluoroethylene will also be referred to as "CTFE," and trifluoroethylene will also be referred to as "HFO-1123." Known methods for producing CTFE include the zinc dechlorination method of 1,1,2-trichloro-1,2,2-trifluoroethane, as well as a hydrogen reduction method of 1,1,2-trichloro-1,2,2-trifluoroethane using a catalyst (for example, Patent Document 1). Hereinafter, 1,1,2-trichloro-1,2,2-trifluoroethane will also be referred to as "CFC-113." HFO-1123 can be produced, for example, by reacting CTFE obtained by reacting CFC-113 with hydrogen, and then reacting the CTFE with hydrogen. Alternatively, HFO-1123 can be obtained directly as a by-product in the reaction of CFC-113 with hydrogen.

[0003] Chinese Patent Application Publication No. 105457651

[0004] When the objective is to efficiently obtain HFO-1123, it is desirable that the total selectivity of CTFE and HFO-1123 is high in the reaction of CFC-113 with hydrogen, rather than the selectivity of CTFE alone. The present disclosure aims to provide a production method that achieves a high total selectivity of CTFE and HFO-1123 in the reaction of CFC-113 with hydrogen.

[0005] The present disclosure includes the following aspects. <1> A method for producing chlorotrifluoroethylene and trifluoroethylene, comprising contacting a raw material composition containing 1,1,2-trichloro-1,2,2-trifluoroethane, hydrogen, and water, wherein the raw material composition has a water content of 200 ppm by mass or less relative to the total raw material composition, with a catalyst to produce chlorotrifluoroethylene and trifluoroethylene by reacting 1,1,2-trichloro-1,2,2-trifluoroethane with hydrogen. <2> The method according to <1>, wherein the catalyst contains a first metal element that is at least one selected from the group consisting of Pd, Pt, Ni, Ir, Ru, Rh, and Os, and a second metal element that is at least one selected from the group consisting of Cu, Fe, Au, Ag, Zn, Sn, and Co. <3> The method according to <1>, wherein the catalyst contains a first metal element that is Pd or Pt, and a second metal element that is Cu. <4> The production method according to any one of <1> to <3>, wherein the raw material composition has a water content of 50 ppm by mass or less relative to the entire raw material composition. <5> The production method according to any one of <1> to <4>, wherein the raw material composition comprises a composition containing 1,1,2-trichloro-1,2,2-trifluoroethane obtained through at least the following steps: a pre-reaction step of reacting 1,1,2-trichloro-1,2,2-trifluoroethane with hydrogen to produce chlorotrifluoroethylene and trifluoroethylene, thereby obtaining a first composition containing 1,1,2-trichloro-1,2,2-trifluoroethane, chlorotrifluoroethylene, trifluoroethylene, and hydrogen chloride; a water-contacting step of contacting the first composition with water to remove at least a portion of the hydrogen chloride, thereby obtaining a second composition containing water; a water-removal step of removing at least a portion of the water from the second composition; and a product-separation step of separating at least a portion of the chlorotrifluoroethylene and trifluoroethylene from the second composition. <6> The production method according to any one of <1> to <5>, wherein the total selectivity of chlorotrifluoroethylene and trifluoroethylene in the reaction is 94% or more.<7> The production method according to any one of <1> to <6>, wherein the raw material composition does not contain a diluent, or further contains a diluent and the content of the diluent relative to the entire raw material composition is 5.0 volume % or less. <8> The production method according to any one of <1> to <7>, wherein the content of hydrogen in the raw material composition is 5.0 times or less, on a volume basis, the content of 1,1,2-trichloro-1,2,2-trifluoroethane.

[0006] According to the present disclosure, there is provided a process for producing CTFE and HFO-1123 with a high total selectivity in the reaction of CFC-113 with hydrogen.

[0007]

[0023] The following describes embodiments of the present disclosure. These descriptions and examples are intended to illustrate the embodiments and are not intended to limit the scope of the embodiments.

[0008] In the present disclosure, a numerical range indicated using "to" means a range that includes the numerical values ​​before and after "to" as the minimum and maximum values, respectively. In the numerical ranges described in stages in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. Furthermore, in the numerical ranges described in the present disclosure, the upper or lower limit value described in a certain numerical range may be replaced with a 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 there are multiple substances corresponding to each component, the amount of each component means the total amount of multiple substances, unless otherwise specified.

[0009] [Method for Producing CTFE and HFO-1123] A production method according to one embodiment of the present disclosure is a method for producing CTFE and HFO-1123, which comprises contacting a raw material composition containing 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113), hydrogen, and water, wherein the raw material composition has a water content of 200 ppm by mass or less relative to the entire raw material composition, with a catalyst, and producing chlorotrifluoroethylene (CTFE) and trifluoroethylene (HFO-1123) by reacting CFC-113 with hydrogen. Hereinafter, the water content relative to the entire composition is also referred to as the "water content of the composition."

[0010] As described above, in order to efficiently obtain HFO-1123, a high total selectivity for CTFE and HFO-1123 is required in the reaction of CFC-113 with hydrogen. In this embodiment, a high total selectivity for CTFE and HFO-1123 is obtained by ensuring that the water content of the raw material composition is 200 ppm by mass or less. The reason for this is not clear, but is presumed to be as follows.

[0011] When CTFE and HFO-1123 are produced by reacting CFC-113 with hydrogen, the target compounds, CTFE and HFO-1123, both have unsaturated bonds. Therefore, if the raw material composition contains more than 200 ppm by mass of water, it is thought that water vapor heated to the reaction temperature will cause a hydrolysis reaction of the generated target compound, converting it into a by-product. In addition, if the raw material composition contains water, it is thought that side reactions will be more likely to occur due to water adsorption on the active sites of the catalyst, and that side reactions will also be more likely to occur due to modification of the catalyst surface, detachment, etc., caused by water vapor heated to the reaction temperature. In particular, if the raw material composition contains a pre-reaction composition, as described below, the water content of the raw material composition is likely to be high. Furthermore, if a raw material composition with a high water content is used to react CFC-113 with hydrogen, hydrolysis reactions, side reactions, etc. of the target compound will be more likely to occur, and the total selectivity of CTFE and HFO-1123 will be lower. In contrast, in the present embodiment, the water content of the raw material composition is 200 ppm by mass or less, and therefore it is presumed that the hydrolysis reaction and side reactions of the target compound are less likely to occur, and a high total selectivity for CTFE and HFO-1123 can be obtained.

[0012] An embodiment of the production method of the present disclosure will be described in detail below. In a production method according to an embodiment of the present disclosure, for example, CFC-113 and hydrogen as raw materials are supplied to a reactor containing a catalyst, and a raw material composition containing CFC-113, hydrogen, and water is brought into contact with the catalyst within the reactor. CFC-113 and hydrogen may be supplied to the reactor separately, or a raw material composition in which CFC-113 and hydrogen are mixed in advance may be supplied to the reactor. When CFC-113 and hydrogen are supplied to the reactor separately, examples of water contained in the raw material composition include water mixed in at least one of CFC-113 and hydrogen before supply to the reactor. Note that when CFC-113 is brought into contact with the catalyst, it may be in either a gas phase or a liquid phase, with a gas phase being preferred.

[0013] The production method of this embodiment may be a continuous method or a batch method. In a continuous production method, for example, the steps of supplying CFC-113 and hydrogen to a reactor, bringing a raw material composition containing CFC-113, hydrogen, and water into contact with a catalyst in the reactor, and removing from the reactor a product composition containing CTFE and HFO-1123 produced by the reaction of CFC-113 and hydrogen.

[0014] The reactor may be any reactor with any shape or structure that can withstand the reaction temperature and pressure described below, and examples thereof include a cylindrical vertical reactor. When the production method of this embodiment is a continuous process, the cylindrical vertical reactor may be used as a reaction path. Examples of materials for the reactor include alloys containing iron and nickel as main components. The reactor may also be equipped with a heating means such as an electric heater.

[0015] <Raw material composition> The raw material composition refers to all components supplied to a reactor. The raw material composition contains at least the raw materials CFC-113 and hydrogen, and water. When other components such as a diluent are supplied to a reactor as needed, the other components are also contained in the raw material composition. The total content of CFC-113 and hydrogen in the entire raw material composition is, for example, 50% by volume or more, and from the viewpoint of production amount, it is preferably 60% by volume or more, more preferably 70% by volume or more, even more preferably 80% by volume or more, particularly preferably 90% by volume or more, and extremely preferably 95% by volume or more. Each component contained in the raw material composition will be described below.

[0016] (Water) In this embodiment, the water content of the raw material composition is 200 ppm by mass or less. When the gaseous raw material composition is brought into contact with the catalyst in a reactor, the water content of the raw material composition means the content of water relative to the total amount of all components of the gas supplied to the reactor.

[0017] The water content is measured by the Karl Fischer method in accordance with JIS K 0068:2001 using a Karl Fischer water content meter. When the raw material composition is brought into contact with the catalyst in a reactor, the water content may be measured on a sample obtained by taking a portion of the raw material composition before it is supplied to the reactor and brought into contact with the catalyst, or on a sample before it is supplied to the reactor. When CFC-113 and hydrogen are supplied separately to the reactor, the water content of the CFC-113 before supply and the water content of the hydrogen gas before supply may be measured separately, and the water content of the raw material composition in the reactor may be calculated taking into account the supply ratio.

[0018] The water content of the raw material composition is 200 ppm by mass or less, preferably 100 ppm by mass or less, more preferably 50 ppm by mass or less, even more preferably 15 ppm by mass or less, particularly preferably 10 ppm by mass or less, and extremely preferably 5 ppm by mass or less. The lower limit of the water content of the raw material composition is not particularly limited. The water content of the raw material composition may be 0.1 ppm by mass or more, 0.5 ppm by mass or more, or even 1 ppm by mass or more. The method for controlling the water content of the raw material composition within the above range is not particularly limited, and examples include methods using a desiccant such as a molecular sieve or activated alumina. In the method using a desiccant, the raw material composition may be prepared using at least one of CFC-113 contacted with a desiccant and hydrogen contacted with a desiccant, or the prepared raw material composition may be contacted with a desiccant.

[0019] (CFC-113 and Hydrogen) CFC-113 can be obtained, for example, by fluorinating tetrachloroethylene with hydrogen fluoride in the presence of a catalyst. The content of CFC-113 relative to the entire raw material composition is, for example, 9 to 91% by volume, and from the viewpoint of the productivity of CTFE and HFO-1123, it is preferably 16 to 67% by volume, and more preferably 20 to 50% by volume. The content of hydrogen relative to the entire raw material composition is, for example, 9 to 91% by volume, and from the viewpoint of the productivity of CTFE and HFO-1123, it is preferably 33 to 84% by volume, and more preferably 50 to 80% by volume.

[0020] From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the hydrogen content in the raw material composition is preferably 10 times or less, more preferably 5.0 times or less, and even more preferably 4.0 times or less, by volume, relative to the CFC-113 content. In other words, the volume ratio of the hydrogen content to the CFC-113 content (H ２ The volume ratio (H / CFC-113) is preferably 10 or less, more preferably 5.0 or less, and even more preferably 4.0 or less. ２ It is presumed that by making the volume ratio (H / CFC-113) equal to or less than the upper limit, the production of 1,1,2-trifluoroethane which forms an azeotrope with CTFE is suppressed, the separability of the target compound and by-products is improved, and the target compound with high purity is more likely to be obtained. ２ From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the volume ratio (H ２ / CFC-113) is preferably 0.1 to 10, more preferably 0.5 to 5.0, and even more preferably 1.0 to 4.0.

[0021] (Diluent) The raw material composition may or may not contain a diluent as necessary. When the raw material composition contains a diluent, the water content of the raw material composition means the water content relative to the entire raw material composition including the diluent. Specific examples of the diluent include nitrogen, argon, helium, carbon dioxide, etc. One of these diluents may be used alone, or two or more may be used in combination. From the viewpoint of low reactivity, nitrogen, argon, and helium are preferred as diluents.

[0022] The diluent is used for the purpose of, for example, reducing the influence of reaction heat by adjusting the concentration of the raw material low. In this embodiment, since the amount of reaction heat generated is small, a high total selectivity for CTFE and HFO-1123 can be obtained without using a diluent. In addition, when a diluent is not used, there is also the advantage that a step of separating the diluent from the produced CTFE and HFO-1123 is not required. The content of the diluent relative to the entire raw material composition is preferably 5.0 vol% or less, more preferably 4.0 vol% or less, and even more preferably 3.0 vol% or less.

[0023] (Pre-reaction Composition) The raw material composition may comprise a pre-reaction composition containing CFC-113 obtained through at least the following steps: a pre-reaction step in which CFC-113 is reacted with hydrogen to produce CTFE and HFO-1123 and thereby obtain a first composition containing CFC-113, CTFE, HFO-1123, and hydrogen chloride; a water contacting step in which water is contacted with the first composition to remove at least a portion of the hydrogen chloride to obtain a second composition containing water; a water removal step in which at least a portion of the water is removed from the second composition; and a product separation step in which at least a portion of the CTFE and HFO-1123 is separated from the second composition. In other words, the raw material composition may comprise CFC-113 that remains unreacted in the pre-reaction step.

[0024] In the pre-reaction step, hydrogen chloride is released by the reaction of CFC-113 with hydrogen. Therefore, the first composition contains hydrogen chloride. That is, the first composition contains, for example, CFC-113 that remains unreacted in the pre-reaction step, and CTFE, HFO-1123, and hydrogen chloride produced in the pre-reaction step. Therefore, in order to remove hydrogen chloride from the first composition, a water contact step is carried out in which the first composition is brought into contact with water.

[0025] In the water contact step, the first composition is contacted with water by, for example, alkaline washing, in which the first composition is passed through an aqueous solution of a basic compound such as sodium hydroxide, potassium hydroxide, potassium bicarbonate, potassium carbonate, or ammonia; or water washing, in which the first composition is passed through water such as ion-exchanged water. In the water contact step, it is preferable to perform at least one of alkaline washing and water washing, and it is more preferable to perform both alkaline washing and water washing. When both alkaline washing and water washing are performed in the water contact step, either one may be performed first, and it is more preferable to perform water washing after alkaline washing. By subjecting the first composition to the water contact step, a second composition is obtained which has a lower hydrogen chloride content and a higher water content than the first composition.

[0026] The second composition contains, for example, CFC-113 that remains unreacted in the pre-reaction step, CTFE and HFO-1123 produced in the pre-reaction step, and water that is mixed in in the water contact step. Therefore, the second composition is subjected to a water removal step in which at least a portion of the water is removed, and a product separation step in which at least a portion of the CTFE and HFO-1123 is separated. The water removal step and the product separation step may be carried out simultaneously or separately. When the water removal step and the product separation step are carried out separately, the product separation step may be carried out after the water removal step, or the water removal step may be carried out after the product separation step.

[0027] In the water removal step, at least a portion of the water is removed from the second composition, for example, by contacting the second composition with a desiccant such as a molecular sieve. In the water removal step, it is sufficient to remove at least a portion of the water contained in the second composition, but from the viewpoint of keeping the water content of the raw material compound within the above-mentioned range, it is preferable to remove as much water as possible from the second composition. In the product separation step, at least a portion of the CTFE and HFO-1123 are separated from the second composition, for example, by distillation. In the product separation step, it is sufficient to separate at least a portion of the CTFE and HFO-1123 contained in the second composition, but from the viewpoint of efficiently obtaining the target compound, it is preferable to separate as much of the CTFE and HFO-1123 as possible from the second composition.

[0028] By subjecting the second composition to the water removal step and product separation step, a pre-reaction composition is obtained that contains at least CFC-113 and has lower contents of water, CTFE, and HFO-1123 than the second composition. The pre-reaction composition may be a composition consisting of CFC-113, or may contain at least one of CTFE and HFO-1123 that was not completely separated in the product separation step. Furthermore, the pre-reaction composition may contain a trace amount of water that was not completely removed in the water removal step, so long as the water content of the raw material compound is within the above-mentioned range. When the first composition contains hydrogen that remains unreacted in the pre-reaction step, the pre-reaction composition may contain hydrogen, or may be one from which at least a portion of the hydrogen has been removed. Furthermore, when the first composition contains a diluent, the pre-reaction composition may contain the diluent, or may be one from which at least a portion of the diluent has been removed. The pre-reaction composition obtained as described above is, for example, mixed with hydrogen and used as a raw material composition.

[0029] <Catalyst> The catalyst may be a metal catalyst containing at least one metal element. Examples of the metal element include Pd, Pt, Ni, Ir, Ru, Rh, Os, Cu, Fe, Au, Ag, Zn, Sn, and Co. The catalyst may contain only one metal element or two or more metal elements. The amount of catalyst used is determined depending on the amounts of CFC-113 and hydrogen, which are raw materials, supplied to the reactor, etc.

[0030] From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the catalyst preferably contains a catalyst containing at least one first metal element selected from the group consisting of Pd, Pt, Ni, Ir, Ru, Rh, and Os, and at least one second metal element selected from the group consisting of Cu, Fe, Au, Ag, Zn, Sn, and Co. Hereinafter, a catalyst containing the first metal element and the second metal element will also be referred to as a "specific catalyst." The first metal element and the second metal element may exist individually or as an alloy. From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the specific catalyst preferably contains a first metal element that is Pd or Pt, and a second metal element that is Cu. In other words, the catalyst preferably contains at least one of a Pd—Cu catalyst and a Pt—Cu catalyst as the specific catalyst.

[0031] The specific catalyst contains a first metal element having a relatively high affinity for hydrogen gas and a second metal element having a relatively low affinity for hydrogen gas. In a catalytic reaction using the specific catalyst, it is presumed that the reactivity between CFC-113 and hydrogen is controlled by utilizing the difference in affinity for hydrogen gas. Therefore, it is thought that when water is adsorbed onto the surface of the specific catalyst, the reactivity on the catalyst surface changes, resulting in the generation of by-products. On the other hand, in this embodiment, since the water content of the raw material composition is within the above range, it is presumed that the adsorption of water onto the surface of the specific catalyst is suppressed, thereby suppressing the generation of by-products, and a high total selectivity for CTFE and HFO-1123 is obtained.

[0032] The specific catalyst may contain other metal components in addition to the first metal element and the second metal element, as necessary. Examples of other metal components include Bi and Al. From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the content of the other metal components is preferably less than 0.05 mass% each, and more preferably less than 0.5 mass% in total, relative to the entire specific catalyst. From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the content of the first metal element contained in the specific catalyst is preferably 0.10 to 1.6 mass%, more preferably 0.16 to 1.4 mass%, and even more preferably 0.33 to 1.1 mass%, relative to the total of the first metal element and the second metal element. From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the content of the second metal element contained in the specific catalyst is preferably 98.4 to 99.9 mass%, more preferably 98.6 to 99.8 mass%, and even more preferably 98.9 to 99.7 mass%, based on the total of the first metal element and the second metal element.

[0033] The form of the catalyst is not particularly limited, and may be powder, pellet-like, or spherical. The catalyst may be supported on a carrier. The carrier preferably contains activated carbon, and more preferably consists of activated carbon. Activated carbon prepared from raw materials such as wood, charcoal, fruit shells, coconut shells, peat, lignite, and coal can be used, but activated carbon obtained from plant materials is preferable to mineral materials, and coconut shell activated carbon is particularly optimal. Examples of carrier shapes that can be used include shaped carbon with a length of about 2 to 5 mm, crushed carbon with a size of about 4 to 50 mesh, and granular carbon with a size of 2 to 50 mesh. From the viewpoint of improving the total selectivity of CTFE and HFO-1123, the carrier shape is preferably crushed carbon with a size of 4 to 20 mesh or granular carbon with a size of 4 to 20 mesh.

[0034] When the catalyst is supported on a carrier, the amount of the catalyst supported is preferably 0.5 to 50 parts by mass, more preferably 1 to 50 parts by mass, even more preferably 1 to 30 parts by mass, particularly preferably 3 to 30 parts by mass, and extremely preferably 5 to 30 parts by mass, per 100 parts by mass of the carrier, from the viewpoint of being able to sufficiently increase the specific surface area of ​​the catalyst and achieving excellent catalytic activity. When the specific catalyst is supported on a carrier, the first metal element and the second metal element may be supported individually on a carrier and used as a mixture, or a mixture of the first metal element and the second metal element may be supported on a carrier.

[0035] The catalyst may contain a metal salt compound. When the catalyst is a specific catalyst, examples of the metal salt compound include oxides, halides, hydroxides, nitrate compounds, etc. containing a first metal element or a second metal element. For example, when the specific catalyst contains Cu as the second metal element, examples of the metal salt compound include CuO, CuCl, CuCl ２ , CuF, CuF ２ , Cu ２ Cl(OH) ３ , Cu ２ (NO ３ (OH) ３ When the specific catalyst contains Pd as the first metal element, examples of the metal salt compound include PdO, PdCl ２ etc.

[0036] When the catalyst is supported on a carrier, the specific surface area of ​​the entire supported catalyst is, for example, 0.1 to 1500 m ２ / g, and from the viewpoint of improving the total selectivity of CTFE and HFO-1123, 1 to 1500 m ２ / g is preferred, and 100 to 1500m ２ The specific surface area is a value measured by the BET method (BET specific surface area).

[0037] <Reaction Step> The temperature of the raw material composition when it is brought into contact with the catalyst, i.e., the reaction temperature, is preferably 150 to 350°C, more preferably 180 to 300°C, and even more preferably 190 to 300°C, from the viewpoint of improving the total selectivity of CTFE and HFO-1123. The reaction temperature refers to the temperature inside the reactor and is measured using a thermocouple or the like. The pressure when the raw material composition is brought into contact with the catalyst is preferably 0 to 1 MPa, more preferably 0 to 0.9 MPa, and even more preferably 0 to 0.5 MPa, in terms of gauge pressure, from the viewpoint of improving the total selectivity of CTFE and HFO-1123. The pressure refers to the pressure inside the reactor.

[0038] The time for which the raw material composition is brought into contact with the catalyst, i.e., the reaction time, is preferably 1 to 500 seconds, more preferably 1 to 75 seconds, and even more preferably 2 to 50 seconds, from the viewpoint of improving the total selectivity of CTFE and HFO-1123. When the production method is a continuous method, the reaction time (seconds) is calculated, for example, using the following formula: Reaction time (seconds) = [Length of catalyst packed in reactor (cm)] / [Linear velocity (cm / second)] The linear velocity means the length of the raw material composition passing through the catalyst per unit time. Examples of the linear velocity include 0.1 to 100 cm / second, preferably 0.1 to 20 cm / second, and more preferably 0.5 to 20 cm / second.

[0039] In the hydrothermal cracking reaction in the reaction step of CFC-113 and hydrogen, a product composition containing the target compounds CTFE and HFO-1123 is obtained. Compounds contained in the product composition other than CTFE and HFO-1123 include unreacted raw material CFC-113 and hydrogen, water, and, if the raw material composition contains a diluent, 1,1-difluoroethylene (HFO-1132a), 1,2-dichloro-1,2,3,3,4,4-hexafluorocyclobutane, 1,3-dichloro-1,2,2,3,4,4-hexafluorocyclobutane, 1,2-dichloro-1,1,2-trifluoroethane ... Examples of by-products include oroethane (HCFC-123a), 1,1-dichloro-1,2,2-trifluoroethane (HCFC-123b), 1,1-dichloro-2,2-difluoroethylene (CFO-1112), 1-chloro-2,2-difluoroethylene (HFO-1122), 1-chloro-2,2-difluoroethylene (HFO-1122a(E)), and 1-chloro-2,2-difluoroethylene (HFO-1122a(Z)).

[0040] The total selectivity of CTFE and HFO-1123 in the reaction of CFC-113 with hydrogen is preferably 94.0% or more, more preferably 94.3% or more, and even more preferably 94.5% or more, from the viewpoint of efficiently obtaining HFO-1123. The selectivity is determined by analyzing the obtained product composition by gas chromatography. Specifically, the measurement is performed using a gas chromatograph (GC-7890A, manufactured by Agilent Technologies Inc.) as the measuring device, a DB-1 column (manufactured by Agilent Technologies Inc., length 60 m, inner diameter 250 μm, filter thickness 1 μm), and a flame ionization detector (FID) as the detector under the following measurement conditions. Injection temperature: 240°C Sample injection volume: 0.5 mL Split ratio: 60 / 1 Linear velocity: 35.8 cm / sec Start of measurement: Temperature -30°C, holding time 10 minutes Heating rate: 10°C / min End of measurement: Temperature 240°C, holding time 20 minutes Detection temperature: 250°C

[0041] The resulting product composition may optionally include a separation step in which components other than CTFE and HFO-1123 are separated. Examples of the separation step include a raw material separation step in which the raw materials CFC-113 and hydrogen are separated from the product composition, and a hydrogen chloride separation step in which hydrogen chloride is separated from the product composition.

[0042] The CTFE contained in the resulting product composition is useful not only as a raw material for HFO-1123 but also as a raw material for polymers. Furthermore, the HFO-1123 contained in the resulting product composition is useful as a refrigerant that can replace difluoromethane and pentafluoroethane, which are greenhouse gases.

[0043] Hereinafter, the present disclosure will be described in more detail with reference to examples, but the present disclosure is not limited to the following examples as long as it does not depart from the gist of the disclosure.

[0044] [Examples 1 to 4] A Pd—Cu catalyst was used as the catalyst. The Pd—Cu catalyst used was a catalyst composed of 1.0 mass % palladium and 99.0 mass % copper. The Pd—Cu catalyst was supported on activated carbon (4 to 6 mesh granular carbon), and the amount of catalyst supported was 6.41 mass parts per 100 mass parts of the support. The supported catalyst in which the Pd—Cu catalyst was supported on activated carbon was packed into a 20A SUS tubular reactor so that the catalyst length was 30 cm. The mass of the supported catalyst used was 57 g, and the specific surface area of ​​the entire supported catalyst was 1100 m ２ / g.

[0045] A hydrogen reduction reaction of CFC-113 was carried out by passing a raw material composition, which was a mixed gas of CFC-113 and hydrogen, through the catalyst in the reactor. The molar ratio of hydrogen / CFC-113 in the raw material composition was 4 / 1. That is, the volume ratio of the hydrogen content to the CFC-113 content in the raw material composition of each example (H ２ / CFC-113) was set to 4. No diluent was used. The water content of the raw material composition in each example was measured using Karl Fischer (coulometry) by the method described above, and the values ​​were as shown in Table 1. The water content of the raw material composition was adjusted, as necessary, for each of CFC-113 and hydrogen, by passing it through a molecular sieve to remove water, or by passing it through pure water to add water. The reaction conditions for the hydrogen reduction reaction were a reaction temperature of 200°C, a residence time (i.e., reaction time) of 13.9 seconds, a linear velocity of 2.2 cm / sec, and atmospheric pressure in the reactor (i.e., gauge pressure: 0 MPa).

[0046] The crude product gas, which is the product composition obtained by the reaction, was sampled, and the components contained therein were analyzed by gas chromatography, and the conversion of CFC-113, the selectivity of CTFE, the selectivity of HFO-1123, and the total selectivity of CTFE and HFO-1123 were calculated. The measuring device and measuring conditions for the gas chromatographic analysis were as described above. The results are shown in Table 1.

[0047]

[0048] Examples 1 to 3 are working examples, and Example 4 is a comparative example. As shown in Table 1, in Examples 1 to 3 in which the water content of the raw material composition was 200 ppm by mass or less, the total selectivity of CTFE and HFO-1123 was higher than in Example 4.

[0049] The disclosure of Japanese Patent Application No. 2024-018061, filed on February 8, 2024, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. A method for producing chlorotrifluoroethylene and trifluoroethylene, comprising contacting a raw material composition containing 1,1,2-trichloro-1,2,2-trifluoroethane, hydrogen, and water, wherein the water content of the entire raw material composition is 200 mass ppm or less, with a catalyst, and producing chlorotrifluoroethylene and trifluoroethylene by reacting 1,1,2-trichloro-1,2,2-trifluoroethane with hydrogen.

2. The manufacturing method according to claim 1, wherein the catalyst comprises a catalyst containing a first metal element that is at least one selected from the group consisting of Pd, Pt, Ni, Ir, Ru, Rh, and Os, and a second metal element that is at least one selected from the group consisting of Cu, Fe, Au, Ag, Zn, Sn, and Co.

3. The manufacturing method according to claim 1, wherein the catalyst comprises a catalyst containing a first metal element which is Pd or Pt and a second metal element which is Cu.

4. A manufacturing method according to any one of claims 1 to 3, wherein the raw material composition has a water content of 50 mass ppm or less relative to the entire raw material composition.

5. The production method according to any one of claims 1 to 3, wherein the raw material composition comprises a composition containing 1,1,2-trichloro-1,2,2-trifluoroethane obtained through at least the following steps: a pre-reaction step in which 1,1,2-trichloro-1,2,2-trifluoroethane is reacted with hydrogen to produce chlorotrifluoroethylene and trifluoroethylene, thereby obtaining a first composition containing 1,1,2-trichloro-1,2,2-trifluoroethane, chlorotrifluoroethylene, trifluoroethylene, and hydrogen chloride; a water contacting step in which water is contacted with the first composition to remove at least a portion of the hydrogen chloride, thereby obtaining a second composition containing water; a water removal step in which at least a portion of the water is removed from the second composition; and a product separation step in which at least a portion of the chlorotrifluoroethylene and trifluoroethylene is separated from the second composition.

6. The process according to any one of claims 1 to 3, wherein the total selectivity of chlorotrifluoroethylene and trifluoroethylene in the reaction is 94% or more.

7. The manufacturing method according to any one of claims 1 to 3, wherein the raw material composition does not contain a diluent, or further contains a diluent and the content of the diluent relative to the entire raw material composition is 5.0 volume % or less.

8. The production method according to any one of claims 1 to 3, wherein the hydrogen content in the raw material composition is 5.0 times or less, on a volume basis, the 1,1,2-trichloro-1,2,2-trifluoroethane content.

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