Method for producing chlorotrifluoroethylene and trifluoroethylene

Abstract

A method for producing chlorotrifluoroethylene and trifluoroethylene, which is a method for producing chlorotrifluoroethylene and trifluoroethylene by reacting 1, 1, 2-trichloro-1, 2, 2-trifluoroethane with hydrogen in the gas phase in the presence of a diluent, the volume of the diluent supplied to the reactor in which the reaction is performed is 0.4 to 6 times the volume of the 1, 1, 2-trichloro-1, 2, 2-trifluoroethane supplied to the reactor.

Description

Technical Field

[0001] The present invention relates to a process for producing chlorotrifluoroethylene and trifluoroethylene. Background Art

[0002] Patent Document 1 discloses a method for producing chlorotrifluoroethylene by reacting 1,1,2-trichloro-1,2,2-trifluoroethane with hydrogen in the presence of a catalyst. Hereinafter, 1,1,2-trichloro-1,2,2-trifluoroethane is also referred to as "CFC-113" and chlorotrifluoroethylene is also referred to as "CTFE". Patent Document 1 discloses that by using iron or an oxide of iron, nickel, copper, tin or zinc as a catalyst, CTFE can be obtained at a high yield, the activity of the catalyst can be maintained for a long period of time, and the productivity can be improved.

[0003] On the other hand, trifluoroethylene can be produced, for example, by further reacting CTFE obtained by reacting CFC-113 with hydrogen with hydrogen. Alternatively, trifluoroethylene can be directly obtained as a by-product of the reaction of CFC-113 with hydrogen in producing CTFE. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Laid-Open No. 3-173840 Summary of the invention Technical problem to be solved by the invention

[0005] Trifluoroethylene has attracted attention as a refrigerant with a low global warming potential. Hereinafter, trifluoroethylene is also referred to as "HFO-1123". In order to efficiently obtain HFO-1123, in the reaction of CFC-113 and hydrogen, the conversion rate of the raw material CFC-113 is required to be high and the total selectivity of CTFE and HFO-1123 is required to be high.

[0006] The object of the present invention is to provide a production method which can simultaneously achieve an increase in the conversion rate of CFC-113 and an increase in the total selectivity of CTFE and HFO-1123 in the reaction of CFC-113 with hydrogen. Solutions to technical problems

[0007] The present invention includes the following aspects. <1> A method for producing chlorotrifluoroethylene and trifluoroethylene, which comprises reacting 1,1,2-trichloro-1,2,2-trifluoroethane with hydrogen in a gas phase in the presence of a diluent to produce chlorotrifluoroethylene and trifluoroethylene, wherein: The volume of the diluent supplied to the reactor for carrying out the reaction is 0.4 to 6 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor. <2> like <1> The manufacturing method, wherein the diluent contains at least one selected from water vapor, nitrogen, argon and helium. <3> like <1> The manufacturing method, wherein the diluent contains water vapor. <4> like <1> ~ <3> The production method described in any one of the above aspects, wherein no catalyst is provided inside the reactor. <5> like <1> ~ <4> The production method described in any one of the above claims, wherein the volume of the diluent supplied to the reactor is 3 to 6 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor. <6> like <1> ~ <5> The production method described in any one of the preceding claims, wherein the volume of the hydrogen supplied to the reactor is 0.3 to 2 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor. <7> like <1> ~ <6> The production method according to any one of the preceding claims, wherein the reaction temperature is 560°C to 600°C. <8> like <1> ~ <7> The production method according to any one of the preceding claims, wherein the reaction time is 1 second to 12 seconds.

[0008] <9> like <3> The production method includes the step of removing at least a part of the water vapor from the gas composition containing the chlorotrifluoroethylene, the trifluoroethylene and the water vapor as the gas composition obtained by the reaction. <10> like <9> The production method described above, wherein the removing includes liquefying at least a portion of the water vapor at a temperature of 5° C. or less. <11> like <9> or <10> The production method described above does not include a catalyst being arranged inside the reactor. <12> like <9> ~ <11> The production method described in any one of the above claims, wherein the volume of the diluent supplied to the reactor is 3 to 6 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor. <13> like <9> ~ <12> The production method described in any one of the preceding claims, wherein the volume of the hydrogen supplied to the reactor is 0.3 to 2 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor. <14> like <9> ~ <13> The production method according to any one of the preceding claims, wherein the reaction temperature is 560°C to 600°C. <15> like <9> ~ <14> The production method according to any one of the preceding claims, wherein the reaction time is 1 second to 12 seconds. <16> like <1> ~ <15> The production method according to any one of the preceding claims, wherein the 1,1,2-trichloro-1,2,2-trifluoroethane is obtained by fluorinating tetrachloroethylene with hydrogen fluoride in the presence of a catalyst. Effects of the Invention

[0009] According to the present invention, there is provided a production method for simultaneously achieving an increase in the conversion rate of CFC-113 and an increase in the overall selectivity of CTFE and HFO-1123 in the reaction of CFC-113 with hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a diagram showing an example of a reaction apparatus used in the production method of the present invention. DETAILED DESCRIPTION

[0011] Hereinafter, the embodiments of the present disclosure are described in detail. However, the present disclosure is not limited to the following embodiments. In the following embodiments, the constituent elements (including element steps, etc.) are not required except for the cases specifically indicated. The same is true for numerical values ​​and their ranges, and the present invention is not limited thereto.

[0012] The term "process" in the present disclosure includes not only a process that is independent of other processes, but also a process that can achieve the purpose of the process even if it cannot be clearly distinguished from other processes. In the present disclosure, a numerical range expressed by “to” includes a range in which the numerical values ​​described before and after “to” are the minimum value and the maximum value, respectively. Each component in the present disclosure may include a plurality of corresponding substances. When a plurality of substances corresponding to each component are present in the composition, unless otherwise specifically stated, the ratio of each component refers to the total ratio of the plurality of substances present in the composition. In the present disclosure, when an embodiment is described with reference to the drawings, the structure of the embodiment is not limited to the structure shown in the drawings. In addition, the sizes of the components in each figure are schematic, and the relative relationship between the sizes of the components is not limited to this.

[0013] [Manufacturing method] A production method according to one embodiment of the present invention is a method for producing chlorotrifluoroethylene (CTFE) and trifluoroethylene (HFO-1123) by reacting 1,1,2-trichloro-1,2,2-trifluoroethane (CFC-113) with hydrogen in a gas phase. In this embodiment, the reaction is carried out in the presence of a diluent and the volume of the diluent supplied to the reactor for carrying out the reaction is 0.4 to 6 times the volume of the CFC-113 supplied to the reactor. Hereinafter, the ratio of the volume of the diluent supplied to the reactor to the volume of CFC-113 supplied to the reactor is also referred to as "diluent ratio".

[0014] Here, the reaction between CFC-113 and hydrogen in the production method of the present embodiment is represented by the following formula.

[0015]

Chemistry 1

[0016] In this embodiment, CTFE and HFO-1123 are simultaneously produced by using CFC-113 as a raw material and contacting CFC-113 with hydrogen in a gas phase. The reaction is preferably carried out under heating. Specifically, when the raw material CFC-113 is heated in the presence of hydrogen, two molecules of hydrogen chloride are generated by hydrogenation thermal decomposition reaction, and CTFE is generated at the same time. It is believed that the generated CTFE will further react with another molecule of hydrogen to generate HFO-1123. In addition, the above-mentioned "hydrogenation thermal decomposition reaction" refers to a reaction in which hydrogen atoms are added to a compound using hydrogen as a reducing agent under heating conditions.

[0017] In this embodiment, the reaction of CFC-113 and hydrogen is carried out in the presence of a diluent and the diluent ratio is set to 0.4 to 6 times, thereby achieving both an increase in the conversion rate of CFC-113 and an increase in the total selectivity of CTFE and HFO-1123. Specifically, by setting the diluent ratio within the above range, dimerization caused by the intermolecular reaction of CTFE is suppressed, and the production of CTFE and HFO-1123 is promoted. Therefore, it is considered that the total selectivity of CTFE and HFO-1123 is improved. Furthermore, when the diluent ratio is within the above range, it is considered that the hydrogen concentration in the gas phase is high compared to the case where the diluent ratio is larger than the above range, and CFC-113 is more likely to come into contact with hydrogen, thereby improving the conversion rate of CFC-113. Hereinafter, the conversion rate of CFC-113 is also simply referred to as the "conversion rate", and the total selectivity of CTFE and HFO-1123 is also simply referred to as the "total selectivity".

[0018] <Diluent> The diluent is a component for reducing the concentration of the raw material CFC-113 and is a component other than the raw material CFC-113 and hydrogen. The diluent is not limited as long as it is a low-reactive compound, but is preferably a high-boiling compound from the viewpoint of ease of separation from the product. The boiling point of the diluent is preferably higher than 47.5° C., which is the boiling point of CFC-113, at atmospheric pressure, more preferably 70° C. or higher, and further preferably 90° C. or higher.

[0019] As the diluent, water vapor, nitrogen, argon, helium, carbon dioxide, etc. can be specifically mentioned. One of the diluents can be used alone, or two or more of them can be used in combination. The total content of water vapor, nitrogen, argon, helium and carbon dioxide contained in the diluent is preferably 90 volume % or more, preferably 95 volume % or more, preferably 99 volume % or more relative to the total amount of the diluent. From the viewpoint of low reactivity, the diluent preferably contains at least one selected from water vapor, nitrogen, argon and helium. In addition, the diluent more preferably contains at least one selected from water vapor and nitrogen.

[0020] In addition, the diluent more preferably contains water vapor. If the diluent contains water vapor, the total selectivity will be further improved. The reason is not clear, but it is speculated that the side reaction of hydrogen chloride and CTFE is suppressed by the association of hydrogen chloride and water vapor generated by the reduction of CFC-113, so that by-products are not easily generated. In addition, from the perspective of ease of separation, the diluent is also preferably water vapor. Since the product CTFE and HFO-1123 are components with low boiling points, by using high-boiling-point water vapor as a diluent, the product and the diluent can be easily separated, which can reduce the equipment cost of the separation process. The content of water vapor contained in the diluent is preferably 50 volume % or more, preferably 60 volume % or more, preferably 70 volume % or more, preferably 80 volume % or more, preferably 90 volume % or more, relative to the total volume of the diluent.

[0021] From the viewpoint of improving the overall selectivity and the conversion rate, the diluent ratio, that is, the ratio of the volume of the diluent to the volume of CFC-113 supplied to the reactor, is 0.4 to 6 times, preferably 1.5 to 6 times, more preferably 3 to 6 times, and even more preferably 4.5 to 6 times. When the production method of the present embodiment is a continuous method, the diluent ratio can be controlled by adjusting the flow rate of CFC-113 supplied to the reactor and the flow rate of the diluent supplied to the reactor.

[0022] From the viewpoint of productivity of CTFE and HFO-1123, the volume ratio of the diluent to the total volume of CFC-113, hydrogen and the diluent supplied to the reactor is preferably 12 to 82 volume %, more preferably 54 to 71 volume %.

[0023] <CFC-113> From the viewpoint of productivity of CTFE and HFO-1123, the volume ratio of CFC-113 to the total volume of CFC-113, hydrogen and diluent supplied to the reactor is preferably 11 to 59 volume %, more preferably 12 to 30 volume %.

[0024] CFC-113 is obtained, for example, by fluorinating tetrachloroethylene with hydrogen fluoride in the presence of a catalyst using tetrachloroethylene as a raw material. That is, the production method of this embodiment may include a step of fluorinating tetrachloroethylene to obtain CFC-113, and a step of reacting CFC-113 with hydrogen to obtain CTFE and HFO-1123. Examples of the catalyst used for fluorination of tetrachloroethylene include antimony pentachloride and the like. As the temperature during the fluorination of tetrachloroethylene, for example, 45°C to 200°C may be mentioned. As the pressure of fluorination of tetrachloroethylene, for example, 100 kPa to 3500 kPa may be mentioned.

[0025] <Hydrogen> Hydrogen is a raw material that reacts with the raw material CFC-113 in the reaction represented by the above formula. The ratio of the volume of hydrogen to the volume of CFC-113 supplied to the reactor is preferably 0.3 to 2 times, more preferably 1 to 2 times, and further preferably 1.5 to 2 times. Hereinafter, the ratio of the volume of hydrogen to the volume of CFC-113 supplied to the reactor is referred to as the "hydrogen ratio". By making the hydrogen ratio within the above range, it is believed that CFC-113 and hydrogen are easily contacted to improve the conversion rate, and the dimerization caused by the intermolecular reaction of CTFE is suppressed, and the total selectivity is improved. In addition, by making the hydrogen ratio within the above range, compared with the case of being higher than the above range, the side reactions of CFC-113 and CTFE are not easy to proceed, and the excess reduction reaction of HFO-1123 is not easy to proceed, etc., thereby improving the total selectivity. In addition, by making the hydrogen ratio within the above range, compared with the case of being higher than the above range, the volume of CFC-113 supplied to the reactor is increased, thereby improving the productivity of CTFE and HFO-1123. In addition, by making the hydrogen ratio within the above range, compared with the case of being higher than the above range, the unreacted hydrogen becomes less, which can reduce the load of the separation process described later. When the production method of the present embodiment is a continuous method, the above-mentioned hydrogen ratio can be controlled by adjusting the flow rate of CFC-113 supplied to the reactor and the flow rate of hydrogen supplied to the reactor.

[0026] From the viewpoint of improving the total selectivity, the ratio of the volume of hydrogen to the total volume of CFC-113, hydrogen and diluent supplied to the reactor is preferably 59% by volume or less, more preferably 34% by volume or less. In addition, from the viewpoint of improving the conversion rate, the ratio of the volume of hydrogen to the total volume of CFC-113, hydrogen and diluent supplied to the reactor is preferably 4% by volume or more, more preferably 18% by volume or more. From the viewpoint of improving conversion and overall selectivity, the ratio of the volume of hydrogen to the total volume of CFC-113, hydrogen and diluent supplied to the reactor is preferably 4 to 59 volume %, more preferably 18 to 34 volume %.

[0027] <Reaction process> In the manufacturing method of this embodiment, the method for contacting CFC-113 with hydrogen is not particularly limited. The contact can be carried out by supplying CFC-113 and hydrogen into a reaction field of CFC-113 and hydrogen, such as a reactor. Hereinafter, the reactor is used as the reaction field of CFC-113 and hydrogen for description. In addition, in the following description, unless otherwise specified, CFC-113 and hydrogen are in a gas phase.

[0028] The manufacturing method of this embodiment can be a continuous method or a batch method. In the continuous method, for example, the steps of supplying raw materials CFC-113 and hydrogen to the reactor, the step of contacting CFC-113 with hydrogen in the reactor, and the step of discharging CTFE and HFO-1123 from the reactor are all carried out continuously. In the continuous production method, the volume ratio of each component to the diluent ratio, hydrogen ratio and the total volume of CFC-113, hydrogen and diluent supplied to the reactor is expressed as the ratio of volume flow rate per unit time.

[0029] When the production method of the present embodiment is a continuous method, CFC-113, hydrogen, and a diluent may be supplied to the reactor separately or may be mixed in advance. The temperature of CFC-113 supplied to the reactor is preferably 60°C to 575°C, more preferably 60°C to 200°C, from the viewpoint of conducting the reaction in a gas phase and preventing the decomposition of CFC-113. From the viewpoint of improving the reactivity of CFC-113 with hydrogen, it is preferred that hydrogen and diluent are premixed and heated with a preheater. The temperature of the mixture of hydrogen and diluent supplied to the reactor is preferably 100°C to 600°C, more preferably 300°C to 600°C, and even more preferably 575°C to 600°C.

[0030] As the reactor for contacting CFC-113 with hydrogen, any reactor that can withstand the temperature and pressure described below may be used, and its shape and structure are not particularly limited, and for example, a cylindrical vertical reactor may be exemplified. In the case where the manufacturing method of the present embodiment is a continuous type, the cylindrical vertical reactor may also be used as the reaction path. As the material of the reactor, there may be mentioned an alloy containing iron or nickel as a main component, etc. In addition, the reactor may be provided with a heating mechanism such as an electric heater.

[0031] In the present embodiment, the catalyst may be provided inside the reactor or may not be provided. In the present embodiment, it is preferred that the catalyst is not provided inside the reactor. Here, the catalyst is not provided inside the reactor means that the catalyst is not deliberately arranged in the space inside the reactor, and the situation where the wall surface of the reactor etc. plays a catalytic role is also included. By not installing a catalyst inside the reactor, the cost is reduced compared to the case where a catalyst is installed, and there is no need to consider catalyst replacement due to catalyst degradation, etc., and the productivity of CTFE and HFO-1123 is improved. Furthermore, in the present embodiment, the reaction of CFC-113 and hydrogen is carried out in the presence of a diluent and the diluent ratio is 0.4 to 6 times, so that even without installing a catalyst inside the reactor, the conversion rate and the total selectivity are improved. Furthermore, in the present embodiment, a catalyst may be provided inside the reactor.

[0032] The temperature for the reaction of CFC-113 with hydrogen is preferably 560° C. to 600° C., more preferably 560° C. to 585° C., and further preferably 560° C. to 575° C. By making the reaction temperature within the above range, the conversion rate is improved compared with the case where the reaction temperature is lower than the above range. In addition, by making the reaction temperature within the above range, the excessive reaction such as carbonization of organic matter is suppressed compared with the case where the reaction temperature is higher than the above range, and the total selectivity is improved. Here, the temperature of the reaction is the temperature of the gas phase in the reactor, that is, the mixed gas of CFC-113, hydrogen and diluent, and is a value measured by a thermocouple or the like.

[0033] The reaction time of CFC-113 and hydrogen is preferably 1 to 12 seconds, more preferably 1 to 8 seconds, and further preferably 1 to 6 seconds. By making the reaction time within the above range, the hydrogenation thermal decomposition reaction of CFC-113 is fully carried out, and the conversion rate is improved compared with the case where it is shorter than the above range. In addition, by making the reaction time within the above range, CTFE and HFO-1123 can be produced with high productivity, side reactions can be suppressed, and the total selectivity is improved compared with the case where it is longer than the above range. In addition, the reaction time is equivalent to the residence time of CFC-113 and hydrogen in the reactor. In the case where the manufacturing method of the present embodiment is a continuous method, the above-mentioned reaction time is calculated by the total flow rate of CFC-113, hydrogen and diluent supplied to the reactor and the volume of the reactor. In addition, the above-mentioned reaction time can be controlled by adjusting the supply amount (i.e. flow rate) of CFC-113, hydrogen and diluent supplied to the reactor.

[0034] The pressure of the reaction of CFC-113 with hydrogen is preferably normal pressure (i.e. atmospheric pressure). The pressure of the above reaction refers to the pressure in the reactor. In addition, unless otherwise specified in this disclosure, pressure refers to gauge pressure.

[0035] <First Gas Composition> In the hydrogenation thermal decomposition reaction in the reaction step of CFC-113 and hydrogen, a composition containing target products CTFE and HFO-1123 is obtained as the first gas composition. Examples of compounds other than CTFE and HFO-1123 contained in the first gas composition include, in addition to unreacted raw material CFC-113 and hydrogen and 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 (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)), 1-chloro-2,2-difluoroethylene (HFO-1122a(Z)) and other by-products.

[0036] <Separation process> The production method of this embodiment is that after reacting CFC-113 with hydrogen in the gas phase, the production method may include a step of separating the product CTFE and HFO-1123 from components other than CTFE and HFO-1123. That is, the production method of this embodiment may include a separation step of separating components other than CTFE and HFO-1123 from the first gas composition.

[0037] (Raw material separation process) The separation step may include, for example, separating a portion or all of the high boiling component CFC-113 from the first gas composition to obtain a second gas composition having an increased content ratio of CTFE and HFO-1123. Hereinafter, the process of separating CFC-113 from the first gas composition to obtain the second gas composition is referred to as a "raw material separation process". As the method for separating CFC-113 from the first gas composition, there is no particular limitation and it can be arbitrarily selected according to the reaction conditions or the reaction product. For example, the liquefaction separation implemented by removing heat below the standard boiling point of CFC-113, the liquefaction separation implemented by removing heat below the boiling point under the pressure under high pressure conditions, the distillation of extractive distillation, the absorption method dissolved in the absorption liquid, etc. can be cited. These methods can be carried out in a single method or in combination of multiple methods. When carried out in a single method, the reaction can be carried out in one stage or in several stages.

[0038] When water vapor is used as a diluent, the separation step preferably includes removing at least a portion of the water vapor from the gas composition containing at least CTFE, HFO-1123 and water vapor. In addition, the removal of the water vapor preferably includes liquefying at least a portion of the water vapor. By liquefying at least a portion of the water vapor to remove the water vapor, the equipment for the subsequent steps can be reduced. The liquefaction of at least a portion of the water vapor is preferably performed at a temperature of 5° C. or less. The removal of water vapor may be performed together with the separation of CFC-113 from the first gas composition. That is, in the above-mentioned raw material separation step, water vapor may be removed together with CFC-113 from the first gas composition. As a method for separating CFC-113 and water vapor from the first gas composition, it is preferred to perform liquefaction by removing heat under slightly pressurized conditions from the viewpoint of equipment. In addition, the heat removal of CFC-113 and water vapor may be performed directly or indirectly. In addition, the CFC-113 and water recovered by liquefaction separation may be separated after the two phases are separated into an organic phase and an aqueous phase.

[0039] When water vapor is liquefied in the raw material separation step, the liquefaction conditions are preferably in the range of pressure 0 MPa to 0.55 MPa and temperature -40° C. to 100° C. In particular, when both CFC-113 and water vapor are liquefied in the separation step, the liquefaction conditions are more preferably in the range of pressure 0 MPa to 0.55 MPa and temperature -40° C. to 48° C., and further preferably in the range of pressure 0 MPa to 0.55 MPa and temperature -40° C. to 5° C.

[0040] In the raw material separation step, a second gas composition containing unreacted CFC-113 is obtained. In addition to the target CTFE and HFO-1123 and unreacted CFC-113, the second gas composition may also contain other compounds used in the above reaction step, other components generated in the above reaction step, etc. In the raw material separation step, CFC-113 contained in the first gas composition and water vapor when water vapor is used as a diluent are selectively separated. Therefore, the content of CTFE and HFO-1123 in the second gas composition is higher than the content of CTFE and HFO-1123 in the first gas composition.

[0041] The second gas composition can be used directly for various purposes, or preferably further purified. As the purification method, there can be cited the well-known methods such as distillation, adsorption, and washing with an acidic aqueous solution, an alkaline aqueous solution or a neutral aqueous solution. Substances other than CTFE and HFO-1123 contained in the second gas composition can be removed by known methods and the concentration of substances other than CTFE and HFO-1123 contained in the second gas composition can be adjusted. The preferred purification method is a method of distillation under normal pressure, increased pressure or reduced pressure. Distillation under such a pressure can obtain high-purity CTFE and HFO-1123. In addition, the unreacted CFC-113 separated from the second gas composition can be recycled as part of the raw materials for the reaction process.

[0042] In addition, examples of a method for separating unreacted hydrogen from the second gas composition include distillation and adsorption separation using an adsorbent. When nitrogen is used as the diluent, examples of a method for separating nitrogen from the second gas composition include distillation and adsorption separation using an adsorbent. When a rare gas such as argon or helium is used as a diluent, examples of a method for separating the rare gas from the second gas composition include distillation and adsorption separation using an adsorbent.

[0043] The water vapor separated in the raw material separation step can be recovered and reused as a diluent in the reaction step.

[0044] In addition, part of the water vapor used as a diluent may be used as a water source in other steps other than the reaction step, and water used for various purposes in other steps other than the reaction step may be used as part of the diluent. For example, the water vapor used as a diluent may be used as a solvent water for the alkaline aqueous solution used in the hydrogen chloride separation step described later, and the solvent water for the alkaline aqueous solution used for washing the second gas composition may be used as the diluent water vapor in the reaction step.

[0045] (Hydrogen chloride separation process) The separation step may include separating the hydrogen chloride contained in the first gas composition. Hereinafter, the step of separating the hydrogen chloride contained in the first gas composition is referred to as a "hydrogen chloride separation step". The hydrogen chloride separation step may be performed between the reaction step and the raw material separation step, may be performed simultaneously with the raw material separation step, or may be performed after the raw material separation step. Hereinafter, a mode in which the hydrogen chloride separation step is performed between the reaction step and the raw material separation step will be described. When the hydrogen chloride separation step is provided, the amount of hydrogen chloride separated in the raw material separation step is much smaller than the amount of hydrogen chloride separated in the hydrogen chloride separation step.

[0046] The first gas composition may be directly supplied to the hydrogen chloride separation step, but another treatment step may be provided between the reaction step and the hydrogen chloride separation step, and the gas composition subjected to the other treatment may be supplied to the hydrogen chloride separation step. Here, the other treatment is a treatment other than the separation of hydrogen chloride and water vapor, and is a treatment that does not change the composition of substances other than water contained in the first gas composition. Examples of the other treatment include storage in a tank, compression by a compressor, heating, cooling, and the like.

[0047] As a method for separating hydrogen chloride from the first gas composition, distillation, adsorption, neutralization or the like may be mentioned.

[0048] Distillation is a method of separating hydrogen chloride by distilling the first gas composition. Distillation can be performed under normal pressure, under pressure, or under reduced pressure, but is preferably performed under pressure from the viewpoint of improving separation efficiency.

[0049] Adsorption is a method of separating the first gas composition by contacting the first gas composition with an adsorbent so that hydrogen chloride is adsorbed on the adsorbent. The adsorbent may be in a solid phase or in a state (liquid phase) dispersed in a liquid medium in which the adsorbent is insoluble.

[0050] Neutralization is a method of contacting the first gas composition with an alkaline compound to react and separate hydrogen chloride. The alkaline compound may be in a solid phase, a liquid phase, a gas phase, or may be dispersed in a liquid medium. Examples of the alkaline compound include sodium hydroxide, potassium hydroxide, potassium bicarbonate, potassium carbonate, ammonia, and the like. In terms of manufacturing cost, sodium hydroxide is preferred. In the hydrogen chloride separation step of performing the hydrogen chloride separation treatment, water vapor may be removed simultaneously.

[0051] The hydrogen chloride separation step of performing the hydrogen chloride separation treatment obtains a gas composition having a hydrogen chloride content ratio lower than that of the first gas composition. That is, the hydrogen chloride separation step obtains a gas composition having a low hydrogen chloride content ratio and containing CTFE, HFO-1123, a diluent, and unreacted CFC-113. When the production method of this embodiment includes a hydrogen chloride separation step, the gas composition can be used as the first gas composition. In the gas composition obtained in the hydrogen chloride separation step, in addition to the content ratio of acidic components such as hydrogen chloride and hydrofluoric acid, the content ratio of other compounds obtained in the above reaction step and compounds other than acidic components contained in other components generated in the above reaction step may be lower than that of the first gas composition.

[0052] In addition, the gas composition obtained in the hydrogen chloride separation step can be directly supplied to the raw material separation step, but other treatment steps can be provided between the hydrogen chloride separation step and the raw material separation step, and the gas composition after other treatment can be supplied to the raw material separation step. Here, other treatment refers to treatment other than separation of water vapor, and is a treatment that does not change the composition of substances other than water contained in the gas composition. Examples of other treatment include storage in a tank, compression by a compressor, heating, cooling, and the like.

[0053] <Reaction device> Figure 1 A schematic diagram showing an example of a reaction apparatus used in the production method of the present embodiment. Figure 1 The reaction device 1 shown in the figure is equipped with a reactor 7 and a high boiling point receiving tank 9. The reactor 7 is equipped with a heating mechanism such as an electric heater for carrying out the reaction process, and the high boiling point receiving tank 9 is used to carry out the above-mentioned raw material separation process. In addition, the reaction device 1 is equipped with a hydrogen chloride trap 11, a dehydration device 13 and a gas capture container 15 on the downstream side of the high boiling point receiving tank 9. The hydrogen chloride trap 11 is used to separate the hydrogen chloride in the gas composition in the above-mentioned hydrogen chloride separation process, the dehydration device 13 is used to remove the water in the gas composition, and the gas capture container 15 is used to capture the gas composition.

[0054] The inlet side or upstream side of the reactor 7 is connected to a preheating mixer 5 having a heating mechanism such as an electric heater. In order to suppress the influence of heat dissipation, the raw material supply line 6 for supplying raw material gas from the preheating mixer 5 to the reactor 7 is preferably as short as possible and can be kept warm with an insulating material.

[0055] The preheating mixer 5 is connected to a supply line 4 for supplying CFC-113 and a supply line 3 for supplying hydrogen. On the other hand, a diluent is supplied from a diluent line 2, and is heated by a preheater 16 as needed and supplied to the supply line 3 to be mixed with hydrogen. In particular, when water vapor is used as the diluent, it is preheated by the preheater 16 to be gasified and then supplied to the supply line 3. A mixed gas 1 of a diluent and hydrogen is supplied to a preheating mixer 5 via a supply line 3. Meanwhile, CFC-113 is supplied to the preheating mixer 5 via a supply line 4, heated to a predetermined temperature, and mixed with the mixed gas 1 in a vaporized state to become a raw material gas. In the preheating mixer 5, the temperature at which CFC-113 is heated to gasify is, for example, 60°C to 100°C. In the preheating mixer 5, the temperature at which the mixed gas 1 is heated is, for example, 100°C to 600°C.

[0056] The raw material gas obtained by mixing CFC-113 with the mixed gas 1 is supplied to the reactor 7 via the raw material supply line 6. The CFC-113 in the raw material gas supplied to the reactor 7 contacts with the hydrogen in the raw material gas and is converted into CTFE and HFO-1123. Then, in the reactor 7, a first gas composition containing a diluent, hydrogen chloride, unreacted CFC-113, etc. in addition to CTFE and HFO-1123 is obtained.

[0057] The first gas composition obtained in the reactor 7 is supplied to the high boiling receiving tank 9 via the reactor outlet pipeline 8. When using high boiling components, mainly unreacted CFC-113 and water vapor as a diluent, the water vapor is liquefied in the high boiling receiving tank 9. Thus, a second gas composition containing low boiling components CTFE and HFO-1123 is obtained. The liquefaction of CFC-113 and the like in the high boiling receiving tank 9 is performed, for example, by cooling the tank using a refrigerant. When water vapor is used as a diluent, the temperature at which the tank is cooled for liquefying the water vapor can be, for example, 5°C or less.

[0058] The outlet of the high boiling receiving tank 9 is connected to a hydrogen chloride trap 11 containing an alkali aqueous solution via an outlet line 10. The second gas composition obtained in the high boiling receiving tank 9 is supplied to the hydrogen chloride trap 11 and passes through the hydrogen chloride trap 11 containing an alkali aqueous solution, so that the hydrogen chloride contained in the second gas composition is neutralized by the alkali. Then, the second gas composition from which the hydrogen chloride is removed is obtained. As the alkali, for example, an aqueous sodium hydroxide solution can be mentioned.

[0059] The outlet of the hydrogen chloride trap 11 is connected to the dehydration device 13 via the outlet pipeline 12. The second gas composition obtained in the hydrogen chloride trap 11 is supplied to the dehydration device 13. In the dehydration device 13, the water remaining in the second gas composition is removed by the water trap, and the second gas composition is dried. As the water trap, for example, porous adsorbents such as molecular sieves can be cited. After the second gas composition from which the water is removed by the dehydration device 13 is recovered in the gas capture container 15 via the outlet pipeline 14, the components contained in the second gas composition are analyzed by an analysis device such as a gas chromatograph (GC).

[0060] The HFO-1123 obtained as above can be used as a refrigerant replacing the greenhouse gases HFC-32 (difluoromethane) and HFC-125 (pentafluoroethane). In addition, the CTFE obtained as described above can be used as a raw material for polymers in addition to being used as a raw material for HFO-1123.

[0061] In addition, by using water vapor as a diluent, even CTFE and HFO-1123 having a low boiling point (normal boiling point) can be easily separated. As a result, the productivity of HFO-1123 and CTFE is improved while the production cost is reduced. Example

[0062] The embodiments of the present disclosure are described in detail below through examples, but the embodiments of the present disclosure are not limited thereto.

[0063] <Reaction device> In the embodiments and comparative examples, Figure 1 The same reaction apparatus as shown (hereinafter referred to as reaction apparatus (1)).

[0064] (Reaction device (1)) In the reaction device (1), the reactor 7 is a cylindrical vertical reactor made of SUS304 or Inconel 600 (JIS standard) with an inner diameter of 23.4 mm × length 400 mm or an inner diameter of 10.7 mm × length 400 mm. Specifically, in the example where water vapor is not used, the reactor 7 made of SUS304 is used, and in the example where water vapor is used, the reactor 7 made of Inconel 600 is used. In addition, only in Example 3, the size of the reactor 7 is 23.4 mm inner diameter × length 400 mm. The inside of the reactor 7 is heated by an electric furnace.

[0065] The raw material supply pipeline 6 connected to the inlet side of the reactor 7 is as short as possible to reduce the influence of heat dissipation, and is insulated with a ceramic fiber material. The raw material CFC-113 is heated and gasified at 60°C to 100°C by the preheating mixer 5. The hydrogen is mixed with the diluent and heated at 100 to 600°C by the preheating mixer 5, and mixed with the gasified CFC-113. The raw material CFC-113 is supplied through a plunger pump (manufactured by Fuji Pump Co., Ltd.) or a syringe pump (manufactured by YMC Co., Ltd.) (not shown) at the end of the supply line 4 to adjust the flow rate. The raw material hydrogen is supplied through a mass flow controller provided on the supply line 3 to adjust the flow rate. The diluent is supplied in different ways depending on the type of diluent used, that is, nitrogen or water vapor. When the diluent is nitrogen, the flow rate is adjusted and supplied through a mass flow controller provided on the diluent line 2. When the diluent is water vapor, the desalted water is supplied through a liquid mass flow controller provided on the diluent line 2 to adjust the flow rate and then vaporized in a preheater 16, and then mixed with hydrogen.

[0066] The reactor outlet line 8 connected to the outlet side of the reactor 7 was heated to a range of 80 to 1120° C. using a band heater and connected to a high boiling receiving tank 9. In addition, a portion of the gas was sampled from the reactor outlet line 8 using a sampling bag made of polyvinylidene fluoride (PVdF), and the composition of the first gas composition obtained from the reactor outlet was analyzed. The high boiling receiving tank 9 is cooled with a refrigerant to condense the high boiling components. The outlet line 10 connected to the outlet side of the high boiling receiving tank 9 is connected to a hydrogen chloride trap 11 containing a 20 mass % sodium hydroxide aqueous solution. The outlet line 12 connected to the outlet side of the hydrogen chloride trap 11 is connected to a dehydration device 13 filled with 220 g of granular molecular sieve 4A (produced by Tosoh Corporation, columnar product 1.5 mm). In addition, the outlet line 14 connected to the outlet side of the dehydration device 13 is connected to a gas capture container 15 to recover the obtained second gas composition.

[0067] <Analysis conditions> The first gas composition obtained from the reactor outlet was analyzed using gas chromatography (GC-7890A, manufactured by Agilent Technologies). The chromatographic column used was DB-1301 (manufactured by Agilent Technologies, length 60 m×inner diameter 250 μm×thickness 1 μm). The detector used was a hydrogen flame ionization detector (FID). Hereinafter, gas chromatography is also referred to as "GC".

[0068] <Response time> Reaction time refers to the residence time of the reaction gas CFC-113 and hydrogen in the reactor as the reaction temperature zone, and is calculated by dividing the gas flow rate (volume flow rate) by the reactor volume, i.e., the cross-sectional area of ​​the reactor and the reaction length. In addition, by measuring the temperature in the reactor with a thermocouple (made by Sakaguchi Electric Heat Co., Ltd.), it was confirmed that the reaction length was about 200 mm regardless of the reaction conditions. Response time ( / s) = flow rate (mm 3 / s) / cross-sectional area (mm 2 ) / reaction length (mm)

[0069] [Example 1] The temperature inside the reactor 7 of the reaction device (1) was set to 575° C., and a mixed gas consisting of 12% by volume of CFC-113, 18% by volume of hydrogen, and 70% by volume of water vapor as a diluent was supplied to the reactor 7. The mixed gas was allowed to flow continuously, and was analyzed after 1, 2, and 3 hours. The analysis results were unchanged, thereby confirming that the composition of the first gas composition as the outlet gas was stable after 1 hour from the start of the reaction.

[0070] Based on the molar ratio (mol %) of each component in the first gas composition obtained by GC analysis, the conversion rate of CFC-113, the selectivity of CTFE, and the selectivity of HFO-1123 were respectively determined as follows.

[0071] In the following calculation formula, (CFC-113) 入口 、(CFC-113) 出口 , (CTFE) 出口 、(HFO-1123) 出口 and (overall) 出口 represents the molar ratio calculated from the GC area ratio of CFC-113 in the raw gas, CFC-113 in the first gas composition obtained from the reactor outlet, CTFE in the first gas composition, HFO-1123 in the first gas composition, and the total organic matter in the first gas composition. In addition, in this example, it is assumed that (CFC-113) 入口 =(Overall) 出口 to calculate.

[0072] In addition, the molar ratio of each component in the first gas composition is calculated by multiplying the area ratio of each component measured by GC by the detection sensitivity coefficient measured using a standard substance with a known composition ratio. In addition, the volume ratio of CFC-113 and the diluent in the raw gas is calculated from the flow ratio of CFC-113 and the diluent.

[0073] [Conversion rate of CFC-113 (mol %)] The conversion rate of CFC-113 refers to the ratio of CFC-113 consumed by the reaction to other components including CTFE and HFO-1123. The conversion rate of CFC-113 is calculated by the following formula. Conversion rate of CFC-113 (mol%) = {1-(CFC-113) 出口 / (CFC-113) 入口}×100

[0074] [CTFE selectivity (mol %)] The selectivity of CTFE refers to the ratio of CFC-113 converted to CTFE after the reaction. The selectivity of CTFE is calculated by the following formula. CTFE selectivity (mol%) = (CTFE) 出口 / {1-(CFC-113) 出口 / (CFC-113) 入口}×100

[0075] [Selectivity of HFO-1123 (mol%)] The selectivity of HFO-1123 refers to the ratio of CFC-113 converted to HFO-1123 after the reaction. The selectivity of HFO-1123 is calculated by the following formula. Selectivity of HFO-1123 (mol%) = (HFO-1123) 出口 / {1-(CFC-113) 出口 / (CFC-113) 入口}×100

[0076] Additionally, these results are averages of analyses of samples collected from the time the reaction stabilized until the reaction was completed.

[0077] The calculation results of the conversion rate of CFC-113, the selectivity of CTFE, the selectivity of HFO-1123 and the total selectivity of (CTFE+HFO-1123) are shown in Table 1 together with the reaction conditions, i.e., the flow rate ratio (volume %) of CFC-113 supplied to the reactor, the flow rate ratio (volume %) of hydrogen, the type of diluent, the flow rate ratio (volume %) of the diluent, the reaction temperature (°C) and the reaction time. The reaction temperature is the temperature inside the reactor 7 and is a value measured by a thermocouple. The reaction time is the time during which the raw material CFC-113 is in contact with hydrogen in the reaction temperature range and is a value obtained by the above method.

[0078] [Examples 2~13] The reaction was continuously carried out in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 1. The conversion of CFC-113, the selectivity of CTFE, the selectivity of HFO-1123, and the total selectivity of (CTFE+HFO-1123) were determined in the same manner as in Example 1. The obtained results are shown in Table 1. In Table 1, “-” means no diluent was used.

[0079] Table 1

[0080] In the above examples, Examples 1 to 4 are embodiments, and Examples 5 to 13 are comparative examples. As shown in Table 1, Examples 1 to 4 achieve both an increase in the conversion of CFC-113 and an increase in the overall selectivity of CTFE and HFO-1123 compared to Examples 5 to 13.

[0081] The entire disclosure of Japanese Patent Application No. 2022-151981 filed on September 22, 2022 is incorporated herein by reference. In addition, all documents, patent applications, and technical specifications described in this specification are incorporated into this specification by reference to the same extent as if the parts incorporated by reference in each document, patent application, and technical specification were specifically and separately described. Explanation of symbols

[0082] 1. Reaction device 2 diluent pipeline 3,4 Supply pipeline 5. Preheat the mixer 6Raw material supply pipeline 7 Reactor 8 Reactor outlet pipeline 9 High boiling receiving tank 10,12,14 export pipeline 11 Hydrogen chloride trap 13Dehydration device 15Gas Capture Container 16 Preheater.

Claims

1. A method for producing chlorotrifluoroethylene and trifluoroethylene, which comprises reacting 1,1,2-trichloro-1,2,2-trifluoroethane with hydrogen in a gas phase in the presence of a diluent to produce chlorotrifluoroethylene and trifluoroethylene, wherein: The volume of the diluent supplied to the reactor for carrying out the reaction is 0.4 to 6 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor.

2. The manufacturing method according to claim 1, wherein: The diluent includes at least one selected from water vapor, nitrogen, argon and helium.

3. The manufacturing method according to claim 1, wherein: The diluent comprises water vapor.

4. The production method according to any one of claims 1 to 3, wherein No catalyst is arranged inside the reactor.

5. The production method according to any one of claims 1 to 3, wherein The volume of the diluent supplied to the reactor is 3 to 6 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor.

6. The production method according to any one of claims 1 to 3, wherein The volume of the hydrogen supplied to the reactor is 0.3 to 2 times the volume of the 1,1,2-trichloro-1,2,2-trifluoroethane supplied to the reactor.

7. The production method according to any one of claims 1 to 3, wherein The reaction temperature is 560°C to 600°C.

8. The production method according to any one of claims 1 to 3, wherein The reaction time is 1 second to 12 seconds.

9. The manufacturing method according to claim 3, wherein: The method includes the step of removing at least a part of the water vapor from the gas composition obtained by the reaction, which includes the chlorotrifluoroethylene, the trifluoroethylene, and the water vapor.

10. The manufacturing method according to claim 9, wherein: The removing includes liquefying at least a portion of the water vapor at a temperature of 5° C. or less.

11. The production method according to any one of claims 1 to 3, wherein The 1,1,2-trichloro-1,2,2-trifluoroethane is obtained by fluorinating tetrachloroethylene with hydrogen fluoride in the presence of a catalyst.

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