JPWO2017104828A1 - Method for producing hydrofluoroolefin - Google Patents

Abstract

Providing a method for producing hydrofluoroolefin (HFO) that easily separates diluent gas even at low boiling point and has excellent productivity. A reaction step of contacting HFC (1) with a metal catalyst in the presence of water vapor to convert to HFO (2) to obtain a first gas composition containing HFO and water vapor; A separation step of separating the water vapor from the gas composition to obtain a second gas composition containing the HFO, wherein the HFC / water vapor is 0.5 / 99.5 to 80/20. . CR1R2X1CR3R4X2 (1) CR1R2 = CR3R4 (2) (In the formula (1) and formula (2), R1 to R3 are H or F, R4 is H, F, CH3, CH2F, CHF2 or CF3, R1 to R4 (The total number of fluorine atoms is 1 or more, and the total number of hydrogen atoms of R1 to R4 is 1 or more. One of X1 and X2 is H and the other is F.)

Description

  The present invention relates to a method for producing hydrofluoroolefin, and more particularly, to a method for efficiently producing hydrofluoroolefin from hydrofluorocarbon.

  Hydrofluoroolefins (HFO) such as trifluoroethylene (HFO-1123) and 2,3,3,3-tetrafluoropropene (HFO-1234yf) have a low global warming potential (GWP), so they are greenhouse gases. In recent years, great expectations have been placed on new refrigerants to replace certain difluoromethane (HFC-32) and 1,1,1,2,2-pentafluoroethane (HFC-125).

  Conventionally, as a method for producing HFO-1123, a method using a relatively inexpensive 1,1,1,2-tetrafluoroethane (HFC-134a) as a raw material is known. Moreover, as a manufacturing method of HFO-1234yf, hydrodynamics such as 1,1,1,2,2-pentafluoropropane (HFC-245cb) and 1,1,1,2,3-pentafluoropropane (HFC-245eb) are used. A method using fluorocarbon (HFC) as a raw material is known.

  For example, Patent Document 1 discloses a method for producing HFO-1123 by using a metal fluoride or a metal oxide as a catalyst, and subjecting HFC-134a to a dehydrofluorination reaction. In the production method disclosed in Patent Document 1, a raw material gas containing HFC-134a as a raw material and nitrogen gas as a dilution gas is supplied to the heating reaction zone, and HFC-134a is removed in the presence of a catalyst in the heating reaction zone. A composition containing HFO-1123 is produced by a hydrogen fluoride reaction.

Japanese National Patent Publication No. 10-505337

  However, in the production method disclosed in Patent Document 1, nitrogen gas, which is a dilution gas of HFO-1123 and raw material HFC-134a, is included in the obtained composition. Since the boiling point of HFO-1123 is low, severe conditions of low temperature and high pressure are required to separate HFO-1123 and nitrogen gas in the composition. Therefore, when nitrogen gas is used as the dilution gas, equipment that can make the inside of the reactor low-temperature and high-pressure is necessary to separate HFO-1123 and nitrogen gas after the reaction. Furthermore, such equipment is extremely expensive to manufacture such as electricity bills.

  That is, when separating the HFO-1123 and the nitrogen gas, if the above severe conditions are not achieved, the HFO-1123 and the nitrogen gas cannot be separated. Therefore, in the manufacturing method disclosed in Patent Document 1, the purification efficiency of HFO-1123 is too low, and, for example, the feasibility is extremely low when mass production is attempted industrially.

  The problem to be solved by the present invention is that, even when the boiling point (standard boiling point) of HFO, which is a production objective compound, is low, HFO and diluent gas can be easily separated, and the productivity is excellent. It aims at providing the manufacturing method of HFO.

  In the present specification, for halogenated hydrocarbons, the abbreviation of the compound is described in parentheses after the compound name, but in this specification, the abbreviation is used instead of the compound name as necessary. In addition, when a compound name or abbreviation is described without particular mention, it indicates that the compound name or abbreviation is an E-form and / or a Z-form. In addition, when (E) is added after the compound name or abbreviation, the compound name or abbreviation is E-form, and when (Z) is added after the compound name or abbreviation, the compound name or abbreviation is Z. Indicates body. In the present specification, saturated hydrofluorocarbon is referred to as HFC and is used separately from HFO.

This invention provides the manufacturing method of HFO which has the structure as described in the following [1]-[10].
[1] In the presence of water vapor, HFC represented by the following formula (1) is brought into contact with a metal catalyst to convert to HFO represented by the following formula (2), and the HFO and the fluorine-containing compound are converted. A reaction step of obtaining a first gas composition containing, and a separation step of separating the fluorine-containing compound from the first gas composition to obtain a second gas composition containing the HFO, The method for producing HFO, wherein a molar ratio (HFC / water vapor) between the HFC and the water vapor supplied to the reaction step is 0.5 / 99.5 or more and 80/20 or less.
CR ¹ R ² X ¹ CR ³ R ⁴ X ² (1)
CR ¹ R ² = CR ³ R ⁴ (2)
(In the above formula (1) and formula (2), R ^{1 to} R ³ are each independently a hydrogen atom or a fluorine atom, and R ⁴ is a hydrogen atom, a fluorine atom, CH ₃ , CH ₂ F, CHF _2. Or CF ₃ , the total number of fluorine atoms of R ^{1 to} R ⁴ is 1 or more, and the total number of hydrogen atoms of R ^{1 to} R ⁴ is 1 or more, one of X ¹ and X ² is a hydrogen atom And the other is a fluorine atom.)
[2] The separation step is a step of liquefying and separating the water vapor contained in the first gas composition at a pressure of −0.1 MPa to 2.0 MPa and a temperature of −30 ° C. to 210 ° C. The manufacturing method of HFO as described in [1] containing this.
[3] The method for producing HFO according to [1] or [2], wherein the HFC is HFC-134a and the HFO is HFO-1123.
[4] The method for producing HFO according to [1] or [2], wherein the HFC is HFC-245cb and / or HFC-245eb, and the HFO is HFO-1234yf.
[5] The method for producing HFO according to any one of [1] to [4], wherein the metal catalyst includes at least one selected from the group consisting of metals, metal oxides, and metal halides.
[6] The metal catalyst is iron, zinc, cobalt, nickel, palladium, platinum, iridium, rhodium, ruthenium, chromium oxide, aluminum oxide, zinc oxide, zirconium oxide, niobium oxide, tin oxide, titanium oxide, oxyfluoride. The method for producing HFO according to any one of [1] to [5], comprising at least one selected from the group consisting of iron, aluminum fluoride, aluminum chloride, chromium fluoride, chromium chloride and silicon oxide.
[7] The method for producing HFO according to any one of [1] to [6], wherein the metal catalyst is in a solid state.
[8] The method for producing HFO according to any one of [1] to [7], wherein the HFC and the water vapor supplied to the reaction step are preheated and then supplied to the reactor.
[9] The method for producing HFO according to [8], wherein the HFC and the water vapor supplied to the reaction step are preheated after being mixed.
[10] The method for producing HFO according to any one of [1] to [9], wherein the temperature at which the HFC is converted to the HFO is 200 ° C. or higher and 1200 ° C. or lower.

  ADVANTAGE OF THE INVENTION According to this invention, even if it is a case where the boiling point (standard boiling point) of HFO is low, HFO and the dilution gas of the raw material HFC can be isolate | separated easily, and the manufacturing method of HFO excellent in productivity is provided. can do.

It is the schematic which shows an example of the reaction apparatus used for the manufacturing method of HFO of this invention.

  Embodiments of the present invention will be described below.

The method for producing HFO of the present invention includes the following reaction step and separation step.
Reaction step: In the presence of water vapor, at least one HFC represented by the formula (1) (hereinafter referred to as “HFC (1)”) is brought into contact with a metal catalyst to form HFO (2) (hereinafter referred to as “ Step of converting to HFO (2) ”) to obtain a first gas composition containing HFO (2) and the water vapor.
Separation step: a step of liquefying and separating the water vapor from the first gas composition to obtain a second gas composition containing HFO (2).

Equation (1) is ^{CR 1 R 2 X 1 CR 3} R 4 X 2, formula (2) is ^{CR 1 R 2 = CR 3 R} 4. Here, in Formula (1) and Formula (2), R ^{1 to} R ³ are each independently a hydrogen atom or a fluorine atom, and R ⁴ is a hydrogen atom, a fluorine atom, CH ₃ , CH ₂ F, or CHF. ₂ or CF ₃ . Further, the total number of fluorine atoms of R ^{1 to} R ⁴ is 1 or more, and the total number of hydrogen atoms of R ^{1 to} R ⁴ is 1 or more. One of X ¹ and X ² is a hydrogen atom, and the other is a fluorine atom. That is, when X ¹ is a hydrogen atom, X ² is a fluorine atom, and when X ¹ is a fluorine atom, X ² is a hydrogen atom.

  In the reaction step, the reaction in which HFO (2) is generated from HFC (1) can be represented by the following reaction formula (3).

When the HFC (1) is appropriately treated under predetermined conditions, a dehydrofluorination reaction in which X ¹ and X ² of the HFC (1) are eliminated simultaneously occurs. And HFO (2) and hydrogen fluoride produce | generate simultaneously by the dehydrofluorination reaction of HFC (1) represented by such Reaction Formula (3).

  In the method for producing HFO of the present invention, HFC (1) and HFO (2) have 2 to 3 carbon atoms.

  In the method for producing HFO of the present invention, examples of the combination of the raw material HFC (1) and the target HFO (2) include trifluoroethane (1,1,1-trifluoroethane (HFC-143a). ), 1,1,2-trifluoroethane (HFC-143), or a mixture of HFC-143a and HFC-143), a process for producing 1,1-difluoroethylene (HFO-1132a), tetrafluoroethane (1 , 1,2,2-tetrafluoroethane (HFC-134), 1,1,1,2-tetrafluoroethane (HFC-134a), or a mixture of HFC-134 and HFC-134a) to trifluoroethylene (HFO) -1123), pentafluoropropane (1,1,1,2,2-pentafluoropro (HFC-245cb), 1,1,1,2,3-pentafluoropropane (HFC-245eb) or a mixture of HFC-245cb and HFC-245eb) to 2,3,3,3-tetrafluoropropene ( HFO-1234yf), pentafluoropropane (1,1,1,3,3-pentafluoropropane (HFC-245fa), HFC-245eb, or a mixture of HFC-245fa and HFC-245eb), 3,3,3-tetrafluoropropene (HFO-1234ze (trans-1,3,3,3-tetrafluoropropene (HFO-1234ze (E))), cis-1,3,3,3-tetrafluoropropene ( HFO-1234ze (Z)), or HFO-1234ze (E) and HF A method for producing a-1234ze (Z) mixtures)) can be mentioned. Among these, the method for producing HFO-1123 from HFC-134a or pentafluoropropane (HFC-245cb, HFC-245eb, and HFC-245cb and HFC can be used to efficiently produce HFO (2). A method of producing HFO-1234yf from a mixture of -245eb is preferred.

  The HFO production method of the present invention may be an all-continuous production method in which the reaction step and the separation step are continuously performed as long as the reaction step and the separation step are performed in this order. Alternatively, it may be an all-batch type manufacturing method in which the separation process is a batch process.

  Further, the reaction process may be a continuous process or a batch process. The separation process may be a continuous process or a batch process as in the reaction process. From the viewpoint of shortening the maintenance time and increasing productivity, the separation step for liquefying and separating water vapor is preferably a continuous step.

  The method for producing HFO of the present invention may further include a step of separating hydrogen fluoride contained in the first gas composition (hereinafter also referred to as “step (A)”). Step (A) may be performed between the reaction step and the separation step, may be performed simultaneously with the separation step, or may be performed after the separation step. By separating the hydrogen fluoride produced in the reaction formula (3) in the step (A), it is possible to reduce the load of the purification process of the HFO (2) as the target product and the recovery process such as HFC (1) and water vapor. Excellent in productivity.

  When the HFO production method of the present invention also includes the step (A) in addition to the reaction step and the separation step, the production method may be an all-continuous production method or an all-batch production method. Alternatively, a part of the processes may be a batch type process, and a partly continuous manufacturing method in which other processes are continuously performed may be used. From the viewpoint of shortening the maintenance time and increasing productivity, the step (A) for separating hydrogen fluoride is preferably a continuous step.

  Hereinafter, the reaction step, the separation step, and the step (A) will be further described.

<Reaction process>
In the reaction step, HFC (1) in the raw material gas is converted to HFO (2) in the presence of water vapor. The conversion from HFC (1) to HFO (2) is performed by contacting HFC (1) with a metal catalyst.

  When the reaction process is a continuous process, the supply of the raw material gas containing HFC (1) as a reaction component and the metal catalyst to the reaction field (for example, a heated reactor) May be continuously supplied, or only a desired component may be supplied continuously, and the others may be supplied batchwise. From the viewpoint of shortening the maintenance time and increasing productivity, it is preferable to continuously supply the raw material gas containing HFC (1) and water vapor to the reactor after supplying the metal catalyst to the reactor in a batch system. .

(Raw material gas)
The raw material gas contains HFC (1) and water vapor which are raw materials. Furthermore, the source gas may contain other compounds in addition to HFC (1) as long as the effects of the present invention are not impaired. The source gas may be partially liquefied. The raw material gas is preferably a gas composition in which the content of HFC (1) is 1 mol% or more with respect to the total molar amount of the compounds contained in the raw material gas.

  Furthermore, the source gas may contain HFO (2) in addition to HFC (1), water vapor, and other compounds optionally contained. Therefore, if the product gas composition obtained by the manufacturing method of various HFO contains HFC (1), the said product gas composition can be used as source gas. Moreover, when the 2nd gas composition obtained by the manufacturing method of HFO of this invention contains HFC (1), you may use this as source gas in a reaction process.

  However, when HFO (2) is contained in the raw material gas, the HFO (2) contained in the raw material gas is the reverse of the reaction that HFO (2) generates in the equilibrium reaction represented by the reaction formula (3). It becomes a factor that the reaction occurs. From such a viewpoint, it is preferable that HFO (2) is not included in the source gas. When HFO (2) is contained, the content ratio of HFO (2) in the raw material gas is preferably 0.001 to 55 mol% with respect to the total molar amount of the compounds contained in the raw material gas. 001-20 mol% is more preferable, and 0.001-5 mol% is most preferable.

Water vapor acts as a dilution gas for HFC (1). In the present invention, unless otherwise specified, water vapor refers to steam or superheated steam composed of water (H ₂ O). Further, the water vapor may be partially mist or liquid.

  Water vapor may be added in the reaction step, or water vapor generated as a by-product in the process of producing HFO (2) may be used in the reaction step as the whole or a part of the dilution gas. It is preferable to add water vapor from the viewpoint that the amount of dilution gas in the reaction step can be adjusted.

  Other compounds contained in the source gas are compounds other than HFC (1), water vapor, and HFO (2). Other compounds include, for example, impurities derived from the production method, dilution gases other than water vapor, and the like.

  Impurities include trifluoromethane (HFC-23), difluoromethane (HFC-32), HFC-134, HFC-143a, HFO-1132a, trans-1,2-difluoroethylene (HFO-1132 (E)), cis -1,2-difluoroethylene (HFO-1132 (Z)), vinyl fluoride (HFO-1141), HFO-1234yf, methane, ethane, ethylene, propane, propylene, acetone, fluorine, hydrogen fluoride, chlorine, chloride Hydrogen etc. are mentioned (however, except HFC (1) contained in source gas and HFO (2) which is a target object).

  Examples of the diluent gas other than water vapor include gases inert to the components contained in the raw material gas in the reaction step, such as helium, argon, carbon tetrachloride, oxygen, carbon dioxide, and nitrogen. In addition, oxygen, carbon dioxide, nitrogen and the like derived from the above production method also act as a dilution gas.

  About the content rate of HFC (1) in source gas, the molar ratio (HFC / water vapor) of HFC (1) and water vapor is 0.5 / 99.5-80 / 20. If HFC / water vapor is 0.5 / 99.5 or more, the cost of temperature increase / decrease can be reduced. A conversion rate can be improved because it is 80/20 or less. HFC / steam is preferably 2/98 to 70/30, more preferably 5/95 to 60/40, from the viewpoints of deterioration of the metal catalyst and the cost of raising and lowering the steam.

  From the viewpoint of suppressing deterioration of the metal catalyst and reducing the load of the HFO (2) purification process performed thereafter by suppressing the generation of unnecessary byproducts, the other compounds in the raw material gas are It is preferably not included. When other compounds are included, the amount is preferably 0.001 to 10 mol%, more preferably 0.001 to 5 mol%, and more preferably 0.001 to 1 mol% based on the total molar amount of the compounds contained in the raw material gas. Mole% is most preferred.

(Metal catalyst)
The metal catalyst used in the reaction step has a catalytic action for the dehydrofluorination reaction of HFC (1). Examples of the metal catalyst include metals (metal simple substance or alloy), metal oxides, metal halides, and the like, and it is preferable to include at least one selected from the group consisting of these. Among these, metal oxides or metal halides are preferable because HFC (1) can be efficiently converted to HFO (2). A metal catalyst may be used individually by 1 type, and may use 2 or more types together.

Examples of the metal constituting the simple metal, alloy, metal oxide, and metal halide include transition metal elements, Group 12 metal elements, Group 13 metal elements, and Group 14 metal elements. Among them, the Group 3 metal element, the Group 4 metal element, the Group 6 metal element, the Group 8 metal element, the Group 10 metal element, the Group 12 metal element, and the Group 13 metal element are preferable, scandium, titanium, More preferred are zirconium, chromium, iron, zinc, and aluminum.
The alloy may be an alloy of two kinds of metals as described above, or an alloy of three or more kinds of metals.
The metal oxide may be one kind of the above-mentioned metal oxide or a complex oxide of two or more kinds of metals.
The metal halide may be a single halide of the above-described metal or a composite halide of two or more metals.

  Specific examples of the metal catalyst include iron, zinc, cobalt, nickel, palladium, platinum, iridium, ruthenium, rhodium, titanium oxide, zirconium oxide, chromium oxide, aluminum oxide, zinc oxide, niobium oxide, tin oxide, fluorine. Examples thereof include iron fluoride, aluminum fluoride, aluminum chloride, chromium fluoride, chromium chloride, silicon oxide, and the like, and preferably includes at least one selected from these groups. Silica oxide is preferably silica gel. Among these, zinc, platinum, palladium, aluminum oxide, aluminum fluoride, zirconium oxide, and chromium oxide are preferable in that HFC (1) can be efficiently converted to HFO (2).

The specific surface area (hereinafter referred to as the BET specific surface area) measured by the BET method of the metal catalyst is preferably 30 to 400 m ² / g. If the BET specific surface area of the metal catalyst is in the above range, the HFC (1) reacts at a high reaction rate, the reaction efficiency is good, and the density of the metal catalyst particles is not too small. Difficult to handle. As for the BET specific surface area of a metal catalyst, 150-400 m < ² > / g is more preferable.

  The metal catalyst may be supported on a carrier. Examples of the carrier include an alumina carrier, a zirconia carrier, a silica carrier, a silica alumina carrier, a carbon carrier represented by activated carbon, a barium sulfate carrier, and a calcium carbonate carrier. Examples of the activated carbon include activated carbon prepared from raw materials such as wood, charcoal, fruit glass, coconut shell, peat, lignite and coal. As the carrier, an alumina carrier is preferably used.

  The metal catalyst is preferably activated in advance from the viewpoint of improving the conversion rate. Examples of the activation treatment method include a method in which a metal catalyst is brought into contact with an activation treatment agent with heating or without heating. Examples of the activation treatment agent include oxygen, hydrogen fluoride, hydrogen chloride, fluorine-containing compounds and the like, and among these, fluorine-containing compounds are preferable. Examples of the fluorine-containing compound include HFC-143, HFC-143a, HFC-134, HFC-134a, HFC-245cb, HFC-245eb, HFC-245fa, HFO-1132a, HFO-1132 (E), and HFO-1132. (Z), HFO-1123, HFO-1234yf, HFO-1234ze, trichlorofluoromethane (HFC-11), dichlorofluoromethane (HFC-21), chlorodifluoromethane (HFC-22), HFC-32, tetrafluoroethylene (FO-14), 1,1,1,2,2-pentafluoroethane (HFC-125) and the like.

  The metal catalyst is preferably subjected to a reactivation treatment in addition to the activation treatment before the reaction. That is, when the activity of the metal catalyst is reduced in the conversion reaction, and the conversion rate of HFC (1) as the raw material component and the selectivity of HFO (2) as the target product are reduced, the metal catalyst is reactivated. It is preferable. It is preferable to recycle the metal catalyst by regenerating the activity of the metal catalyst by reactivation treatment.

  As a method for the reactivation treatment, a method of bringing the metal catalyst after use into contact with the activation treatment agent under heating or non-heating as in the above-described activation treatment performed before use can be mentioned. As the reactivation treatment agent, the same compound as the activation treatment agent can be used.

  From the viewpoint of suppressing side reactions and improving the durability of the metal catalyst, it is preferable to use an inert gas such as nitrogen, carbon dioxide, argon, or helium in order to dilute the activation treatment agent.

(Contact between source gas and metal catalyst)
In the contact between the source gas and the metal catalyst, the metal catalyst is preferably brought into contact with the source gas in a solid state (solid phase).

  Hereinafter, the aspect of the reaction step will be described in which a gas phase raw material gas is continuously supplied into the reactor and brought into contact with the solid phase metal catalyst charged in batch in the reactor. The reaction process in the manufacturing method of HFO is not limited to such an aspect.

  In the embodiment in which the gas phase raw material gas is continuously brought into contact with the solid phase metal catalyst and reacted, by controlling the flow rate per unit time of each gas phase component and water vapor in the raw material gas, The HFC (1) and water vapor content can be controlled.

(Reactor and reaction conditions)
In the reaction step, the shape and structure of the reactor for reacting the raw material gas with the metal catalyst are not particularly limited as long as they can withstand the temperature and pressure described later. Examples of the reactor include a cylindrical vertical reactor. Examples of the material of the reactor include glass, iron, nickel, iron or an alloy containing nickel as a main component. The reactor may include heating means such as an electric heater for heating the inside of the reactor.

  The metal catalyst constituting the solid phase to be charged into the reactor may be accommodated in either a fixed bed type or a fluidized bed type. In the case of a fixed bed type, either a horizontal fixed bed type or a vertical fixed bed type may be used, but when the raw material gas is a mixed gas composed of multiple components, the concentration distribution of each component is generated due to the difference in specific gravity. It is preferable to use a vertical fixed floor type.

  The raw material gas may be supplied to the reactor at room temperature, but in order to increase the reactivity in the reactor, it is preferable to supply the raw material gas after heating (preheating) before supplying it to the reactor. . When preheating the raw material gas, the raw material gas is preferably heated to a temperature of 50 ° C. to 1200 ° C., more preferably 50 to 400 ° C., and then supplied to the reactor.

  When the raw material gas is preheated and supplied to the reactor, the HFC (1) and steam may be preheated separately and then supplied to the reactor, or the HFC (1) and steam are mixed and preheated to react. May be supplied to the vessel. From the viewpoint of simplifying the operation and increasing the productivity, it is preferable to mix HFC (1) and steam and then preheat them and supply them to the reactor.

  When HFC (1) and water vapor are separately preheated and supplied to the reactor, HFC (1) is preferably preheated to a temperature of 50 to 400 ° C, and the water vapor is preheated to a temperature of 50 to 400 ° C. Is preferred. HFC (1) and water vapor may be preheated to the same temperature, or may be preheated so as to have a temperature difference. The preheated HFC (1) and water vapor may be mixed and then supplied to the reactor, or may be supplied separately to the reactor.

  The source gas supplied to the reactor comes into contact with a metal catalyst that forms a solid phase in the reactor. The temperature in the reactor is preferably 200 to 1200 ° C. from the viewpoint of improving the reactivity and improving the life of the metal catalyst. Furthermore, 300-1000 degreeC is more preferable from a viewpoint of reaction efficiency, suppression of a side reaction, and a production facility. Moreover, the pressure in the reactor is not a pressure in the vicinity of the critical point, and is specifically preferably −0.1 to 2 MPa, more preferably −0.1 to 0.5 MPa. The contact time between the raw material gas and the metal catalyst in the reactor is preferably 0.001 to 500 seconds, more preferably 0.5 to 50 seconds, and particularly preferably 5 to 30 seconds. In the present specification, the pressure is indicated by a gauge pressure unless otherwise specified.

(First gas composition)
In the reaction step, a first gas composition containing HFO (2), water vapor, and unreacted HFC (1) can be obtained as the outlet gas of the reactor. In addition to HFO (2), water vapor, and unreacted HFC (1), which are target products, the first gas composition includes other compounds in the reaction process and other components that are by-products generated in the reaction process. May be included. As other components contained in the first gas composition, for example, when HFC (1) is HFC-134a and HFO (2) is HFO-1123, HFO-1141, HFO-1132a, HFO -1132 (Z), HFO-1132 (E), HFC-134, HFC-143, HFC-134a, HFC-125, HFC-23, HFC-32, methane, ethylene, ethane, propylene, propane and the like. . The water vapor used as the dilution gas may be partially liquefied to form water.

<Separation process>
In the separation step, part or all of the water vapor is separated from the first gas composition to obtain a second gas composition having an increased content of HFO (2). The method for separating water vapor is not particularly limited, and can be arbitrarily selected according to reaction conditions and reaction products. For example, liquefaction separation by removing heat below the normal boiling point of water vapor, liquefaction separation by removing heat below the boiling point at the pressure under high pressure conditions, extractive distillation, absorption method to dissolve in absorption liquid, porous adsorbent Examples include an adsorption separation method for adsorbing water and water vapor, and a membrane separation method for separating water and water vapor by passing through a separation membrane. These methods may be performed by a single method, or a plurality of methods may be combined. When it is carried out by a single method, it may be a one-step reaction or may be carried out in several steps. As a method for separating water vapor, liquefaction by heat removal under slightly pressurized conditions is preferable from the viewpoint of equipment. The heat removal may be performed directly on the water vapor or indirectly. Depending on the separation conditions, hydrogen fluoride may be separated in addition to water vapor.

  When the separation step is performed by liquefaction separation, the liquefaction conditions are preferably a pressure of −0.1 to 2.0 MPa, a temperature of −40 to 210 ° C., and a pressure of −0.1 MPa to 2.0 MPa. Hereinafter, the temperature is more preferably −30 ° C. or more and 210 ° C. or less, the pressure is −0.1 to 2.0 MPa, the temperature is more preferably −20 to 150 ° C., and the pressure is −0. It is particularly preferable that the temperature is 1 to 1.0 MPa and the temperature is in the range of -20 to 120 ° C.

(Second gas composition)
In the separation step, a second gas composition containing HFO (2) and unreacted HFC (1) can be obtained. The second gas composition may contain the same compounds and components as the other compounds and other components in the reaction step, in addition to the target HFO (2) and unreacted HFC (1). In the separation step, water vapor contained in the first gas composition is selectively separated. For this reason, the content rate of HFO (2) in the 2nd gas composition becomes higher than the content rate of HFO (2) in the 1st gas composition.

  The second gas composition can be used for various applications as it is, and it is preferable to further perform purification. Examples of the purification method include known methods such as distillation, adsorption, washing with an acidic aqueous solution, a basic aqueous solution or a neutral aqueous solution. Substances other than HFO (2) contained in the second gas composition can be removed by known means to adjust the concentration contained in the second gas composition. Preferably, the purification method is a method of distillation under normal pressure, increased pressure or reduced pressure. By performing distillation under such pressure, high-purity HFO (2) can be obtained. Moreover, the unreacted HFC (1) separated from the second gas composition can be recycled as a part of the raw material gas in the reaction step.

(Water vapor recovery method)
The water vapor separated in the separation step can be recovered. The recovered water vapor can be reused again as a dilution gas in the reaction step.

  In addition, a part of the water vapor used as the dilution gas may be used as a water source in other processes other than the reaction process, and water used for various purposes in other processes other than the reaction process may be used as a dilution gas. It may be used as a part. For example, water vapor used as a dilution gas may be used as water as a solvent for the basic aqueous solution used in the step (A) described later, or the basic aqueous solution used for cleaning the second gas composition. Water as a solvent may be used as water vapor in the reaction step.

<Process (A)>
Furthermore, it is preferable that the manufacturing method of HFO of this invention has the process (A) which isolate | separates the hydrogen fluoride contained in a 1st gas composition. Step (A) may be performed between the reaction step and the separation step, may be performed simultaneously with the separation step, or may be performed after the separation step. Hereinafter, the aspect which has a process (A) between a reaction process and a isolation | separation process is demonstrated about a process (A). In the case of having the step (A), the amount of hydrogen fluoride separated in the separation step described above is very small compared to the amount of hydrogen fluoride separated in the step (A).

  The first gas composition may be supplied to the step (A) as it is, but another processing step is provided between the reaction step and the step (A), and the first gas composition is different from the first gas composition. You may supply the processed thing to a process (A). Here, the other treatments are treatments other than the separation of hydrogen fluoride and water vapor, and treatments that do not change the composition of substances other than moisture contained in the first gas composition. Examples of other treatments include storage in a tank, compression with a compressor, heating, cooling, and the like.

  Examples of the method for separating hydrogen fluoride from the first gas composition include methods such as distillation, adsorption, and neutralization.

  Distillation is a method of separating the hydrogen fluoride by distilling the first gas composition. Although distillation can be performed under normal pressure, under pressure, or under reduced pressure, it is preferably performed under pressure from the viewpoint of improving separation efficiency.

  Adsorption is a method in which the first gas composition is brought into contact with an adsorbent and hydrogen fluoride is adsorbed onto the adsorbent and separated. The adsorbent may be in a solid phase or in a state (liquid phase) dispersed in a liquid medium in which the adsorbent does not dissolve. As the adsorbent, sodium fluoride, potassium fluoride, zeolite, activated carbon and the like can be used. Sodium fluoride is particularly preferable because hydrogen fluoride can be efficiently separated.

Neutralization is a method in which the first gas composition is brought into contact with a basic compound and hydrogen fluoride is reacted to separate. The basic compound may form a solid phase, a liquid phase, or a gas phase, or may be dispersed in a liquid medium. As the basic compound, sodium hydroxide, potassium hydroxide, potassium hydrogen carbonate, potassium carbonate, ammonia and the like can be used. Potassium hydroxide is particularly preferable because hydrogen fluoride can be efficiently separated.
In the step (A) for separating hydrogen fluoride, water vapor may be removed at the same time.

  By the step (A) of performing the separation treatment of hydrogen fluoride, a gas composition having a lower content of hydrogen fluoride than that of the first gas composition is obtained. That is, by the step (A), a gas composition containing a low content of hydrogen fluoride and containing HFO (2), water vapor and unreacted HFC (1) is obtained. When the manufacturing method of HFO of this invention has a process (A), the said gas composition can be used as said 1st gas composition. In the gas composition obtained in the step (A), the content ratio of acidic components such as hydrogen chloride and oxyfluoride, and the content ratio of compounds other than acidic components contained in the other compounds and other components are as follows. It may be lower than the first gas composition.

  In addition, although the gas composition obtained in the step (A) may be supplied to the separation step as it is, another treatment step is provided between the step (A) and the separation step, and the gas composition is You may supply what performed the other process to the isolation | separation process. Here, the other treatment is treatment other than separation of water vapor and treatment that does not change the composition of substances other than moisture contained in the gas composition. Examples of other treatments include storage in a tank, compression with a compressor, heating, cooling, and the like.

<Reactor>
FIG. 1 is a schematic view showing an example of a reaction apparatus used in the method for producing HFO of the present invention. The reaction apparatus 1 includes a reactor 2 provided with a heating means such as an electric heater for performing a reaction process, and a water trap 4 for performing a separation process. The reactor 2 may include a heat removal means, but is not essential.

  In addition, the reactor 1 has a hydrogen fluoride trap 3 for performing the step (A), a dehydrator 13 for removing moisture in the second gas composition, a second downstream of the water trap 4. A sampling bag 14 for capturing the gas composition and an analyzer 15 such as a gas chromatography (GC) for analyzing the components contained in the second gas composition are provided.

  The hydrogen fluoride trap 3 is not essential. In the reactor 1, the hydrogen fluoride trap 3 is disposed between the water trap 4 and the dehydrator 13, but may be disposed between the reactor 2 and the water trap 4.

  A metal catalyst 5 is accommodated in the reactor 2 so as to form a vertical fixed bed. Further, the upper part on the inlet side of the reactor 2 is connected to a preheating mixer 6 equipped with heating means such as an electric heater by a raw material gas supply line 7. The source gas supply line 7 is preferably provided with heating means such as an electric heater.

  Connected to the preheating mixer 6 are an HFC supply line 8 for supplying HFC (1) and a steam supply line 9 for supplying water vapor as a dilution gas. The HFC (1) and the steam are respectively introduced into the preheating mixer 6 by the HFC supply line 8 and the steam supply line 9, mixed in the preheating mixer 6 and heated to a predetermined temperature, and then the raw material gas supply line 7 To the reactor 2. The HFC supplied to the reactor 2 comes into contact with the metal catalyst 5 in the presence of water vapor and is converted to HFO (2). And the 1st gas composition containing HFO (2), water vapor | steam, hydrogen fluoride, and unreacted HFC (1) is obtained. The water vapor may be supplied to the water vapor supply line 9 as liquid water, or may be heated and vaporized in advance and supplied to the water vapor supply line 9.

  The HFC supply line 8 and the steam supply line 9 may be connected before being connected to the preheating mixer 6, and the HFC (1) and the steam may be mixed before being supplied to the preheating mixer 6. In addition, a preheater (preheater) equipped with an electric heater or the like is installed in at least one of the HFC supply line 8 and the steam supply line 9, and at least one of HFC (1) and steam supplied through the line where the preheater is installed. May be supplied to the preheating mixer 6 after preheating.

  The lower part on the outlet side of the reactor 2 is connected to the water trap 4 by a reactor outlet line 10 equipped with heating means such as an electric heater. The first gas composition obtained in the reactor 2 is supplied to the water trap 4, and the first gas composition is removed by the outlet line 10 and the water trap 4, so that the first gas composition in the first gas composition The water vapor used as the dilution gas is liquefied. Thereby, the water vapor contained in the first gas composition is separated, and a second gas composition containing HFO (2) is obtained.

  The outlet of the water trap 4 is connected to a hydrogen fluoride trap 3 containing an alkaline aqueous solution by an outlet line 11. The second gas composition obtained by the water trap 4 is supplied to the hydrogen fluoride trap 3 and passes through the hydrogen fluoride trap 3 in which the alkaline aqueous solution is contained, so that it is contained in the second gas composition. Hydrogen fluoride is neutralized by alkali. And the 2nd gas composition which removed hydrogen fluoride is obtained.

  The outlet of the hydrogen fluoride trap 3 is connected to a dehydrator 13 by an outlet line 12. The second gas composition obtained by the hydrogen fluoride trap 3 is supplied to the dehydrator 13. In the dehydrator 13, the water remaining in the second gas composition is removed without being removed by the water trap, and the second gas composition is dried. The second gas composition from which moisture has been removed by the dehydrator 13 is collected in the sampling bag 14, and then the components contained in the second gas composition are analyzed by the analyzer 15 such as gas chromatography (GC). The

  According to the method for producing HFO of the present invention, even when the boiling point (standard boiling point) of HFO is low, it is possible to easily separate HFO and water vapor as a dilution gas. As a result, the manufacturing cost can be reduced and the productivity of HFO can be increased.

  HFO produced by the production method of the present invention, such as HFO-1123 and HFO-1234yf, is used as a refrigerant in place of greenhouse gases such as HFC-32 and HFC-125, and as a functional material such as a piezoelectric element or a film. It is useful as a raw material monomer and an intermediate for synthesis.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to a following example.

<Reactor>
In the examples and comparative examples, the same reaction apparatus as shown in FIG. 1 (hereinafter referred to as reaction apparatus (1)) was used.

(Reactor (1))
In the reactor (1), the reactor 2 was a vertical fixed bed reactor made of SUS316L (JIS standard) and having an inner diameter of 22.66 mm and a height of 300 mm. The reactor 2 was filled with the metal catalyst 5 shown in each example and comparative example at a height of 100 mm. The inside of the reactor 2 was heated by an electric furnace.

  The raw material gas supply line 7 connected to the inlet side of the reactor 2 was heated by a ribbon heater so as to be in the range of 100 ° C to 140 ° C. HFC-134a which is HFC (1) and water vapor which is a dilution gas were mixed by adjusting the flow rate with a mass flow controller installed in the HFC supply line 8 and a syringe pump (not shown) of the water vapor supply line 9 yuan, respectively. Then, it was configured to be supplied to the preheating mixer 6.

  The reactor outlet line 10 connected to the outlet side of the reactor 2 was heated by a ribbon heater so as to be in the range of 100 ° C. to 140 ° C. and connected to the water trap 4. In addition, the refrigerant was circulated outside the water trap 4 to remove heat so that the temperature in the water trap 4 was in the range of 0 ° C to 10 ° C. The outlet line 11 connected to the outlet side of the water trap 4 was connected to the hydrogen fluoride trap 3 containing a 20% by mass potassium hydroxide aqueous solution. The outlet line 12 connected to the outlet side of the hydrogen fluoride trap 3 was connected to a dehydrator 13 filled with 120 g of pellet-shaped molecular sieves 3A (manufactured by Junsei Chemical Co., Ltd., 1/8 inch pellets). Further, the second gas composition that has passed through the dehydrator 13 is collected by a sampling bag 14 made of polyvinylidene fluoride (PVdF) connected to the dehydrator 13, and then the composition analysis of the second gas composition is performed. The analyzer 15 is configured to perform the process.

<Analysis conditions>
In the analyzer 15 (GC-2010A, manufactured by Shimadzu Corporation), GC was used for the composition analysis of the second gas composition. DB-1 (Agilent Technology Co., Ltd., length 60 m × inner diameter 250 μm × thickness 1 μm) was used as the column. A flame ionization detector (FID) was used as a detector.

<Linear velocity>
The linear velocity means the superficial velocity, and it is assumed that the reactor that circulates the raw material gas is an empty column that is not filled with packing material, and the flow rate (volumetric flow rate) is interrupted by the reactor that is empty. Calculated by dividing by area. The experiment was conducted at a linear velocity of 1 cm / s.
Linear velocity (superficial velocity) (cm / s) = flow rate (cm ³ / s) / cross-sectional area (cm ² )

[Example 1]
The reactor 2 of the reactor (1) is charged with 40 g of an alumina catalyst (Al ₂ O ₃ , manufactured by JGC Catalysts and Chemicals, trade name: ACBM-1, shape: 2 mm spherical), and 300 mL of nitrogen gas is added. It was dried by heating at 350 ° C. for 48 hours while supplying at / min.

  Next, the internal temperature of the reactor 2 was set to 350 ° C., and a mixed gas obtained by mixing 20 mol% of HFC-134a and 80 mol% of nitrogen gas was supplied to the reactor 2 at a linear velocity of 1 cm / s. HFC-134a and nitrogen gas were continuously flowed, and after 8 hours, it was confirmed that the composition of the outlet gas flowing out of the reactor 2 was stable.

  Next, the internal temperature of the reactor 2 was 350 ° C., 20 mol% of HFC-134a and 80 mol% of water vapor as a dilution gas were mixed and supplied to the reactor 2. The composition of the outlet gas (hereinafter referred to as “water trap passage outlet gas”) that has continuously passed HFC-134a and water vapor and passed through the water trap 4, the hydrogen fluoride trap 3, and the dehydrator 13 is stable. It was confirmed. Next, outlet gas samples were taken every two hours after the composition of the outlet gas passing through the water trap was stabilized. The room temperature at the time of sample collection was 15 ° C.

  Based on the molar ratio (mol%) of each component in the water trap passage outlet gas obtained by GC analysis, the conversion rate of HFC-134a and the selectivity of HFO-1123 were determined as follows. It was.

In the following calculation formula, (HFC-134a) _in , (HFC-134a) _out , (HFO-1123) _out and (total) _out are respectively passed through the water trap except for HFC-134a and dilution gas in the source gas. It represents the molar ratio calculated from the GC area ratio of HFC-134a in the outlet gas, HFO-1123 in the water trap passage outlet gas, and the entire water trap passage outlet gas component. In the present embodiment, the calculation is performed assuming that (HFC-134a) _in = (total) _out .

  In addition, the molar ratio of each component in the water trap passage outlet gas is obtained by multiplying the area ratio of each component identified by GC by a detection sensitivity factor measured using a standard substance having a known composition ratio. Calculated. The molar ratio of HFC-134a and water vapor in the raw material gas was calculated from the flow rate ratio of HFC-134a and water.

[Conversion rate of HFC-134a (mol%)]
The conversion rate of HFC-134a refers to the ratio of HFC-134a converted to other components including HFO-1123 by the reaction and consumed. The conversion rate of HFC-134a is calculated by the following formula.
Conversion of HFC-134a (mol%) = {1- (HFC-134a) _out / (HFC-134a) _in } × 100

[Selectivity of HFO-1123 (mol%)]
The selectivity of HFO-1123 refers to the ratio of HFC-134a converted to HFO-1123. The selectivity of HFO-1123 is calculated by the following formula.
Selectivity of HFO-1123 (mol%) =
(HFO-1123) _out / {1- (HFC-134a) _out / (HFC-134a) _in } × 100

  In addition, these results were made into the average value of the analysis of the sample extract | collected after reaction was stabilized until reaction completion.

The calculation results of the conversion rate of HFC-134a and the selectivity of HFO-1123 are shown in the reaction conditions (HFC-134a flow rate (mol%), steam flow rate (mol%), internal temperature (° C) supplied to the reactor)). In addition, it is shown in Table 1.
The internal temperature is the internal temperature of the reactor 2 and is an actually measured value. The linear velocity is the linear velocity of the raw material gas supplied to the reactor.

[Examples 2 to 8]
The reaction was continuously performed in the same manner as in Example 1 except that the reaction conditions were changed as shown in Table 1. Then, the conversion rate of HFC-134a and the selectivity of HFO-1123 were determined in the same manner as in Example 1. The obtained results are shown in Table 1.

[Examples 9 and 10]
40 g of aluminum trifluoride (AlF ₃ , trade name: Aluminum Trifluoride, shape: powder) was charged into the reactor 2 of the reactor (1), and the reaction conditions were changed as shown in Table 1. The reaction was continuously carried out in the same manner as in Example 1 except that. Then, the conversion rate of HFC-134a and the selectivity of HFO-1123 were determined in the same manner as in Example 1. The obtained results are shown in Table 1.

[Example 11]
The reactor 2 of the reactor (1) was charged with 50 g of zirconium dioxide (ZrO ₂ , manufactured by Kanto Chemical Co., Inc., trade name: Zirconium oxide, shape: pellet), and the reaction conditions were changed as shown in Table 1. Was continuously reacted in the same manner as in Example 1. Then, the conversion rate of HFC-134a and the selectivity of HFO-1123 were determined in the same manner as in Example 1. The obtained results are shown in Table 1.

[Example 12]
The reactor 2 of the reactor (1) was charged with 45 g of aluminum oxide (Pd / Al ₂ O ₃ , manufactured by Junsei Chemical Co., Ltd., shape: pellets) supporting 5% by mass of palladium, and the reaction conditions are shown in Table 1. The reaction was continuously carried out in the same manner as in Example 1 except that the changes were made as shown in FIG. Then, the conversion rate of HFC-134a and the selectivity of HFO-1123 were determined in the same manner as in Example 1. The obtained results are shown in Table 1.

[Example 13]
The reaction was continuously performed in the same manner as in Example 1 except that the composition of the source gas and the reaction conditions were changed as shown in Table 2. And the conversion rate of HFC-245eb and the selectivity of HFO-1234yf were computed from the following formula. The obtained results are shown in Table 2.

In the following calculation formula, (HFC-245eb) _in , (HFC-245eb) _out , (HFO-1234yf) _out and (total) _out are the HFC-245eb in the source gas and the water trap passage excluding the dilution gas, respectively. It represents the molar ratio calculated from the GC area ratio of HFC-245eb in the outlet gas, HFO-1234yf in the water trap passage outlet gas excluding the dilution gas, and the entire water trap passage outlet gas component. In this example, the calculation was performed assuming that (HFC-245eb) _in = (total) _out .

HFC-245eb conversion (mol%) = {1- (HFC-245eb) _out / (HFC-245eb) _in } × 100
Selectivity of HFO-1234yf (mol%) =
(HFO-1234yf) _out / {1- (HFC-245eb) _out / (HFC-245eb) _in } × 100

[Example 14]
The reaction was continuously performed in the same manner as in Example 1 except that the composition of the source gas and the reaction conditions were changed as shown in Table 3. And the conversion rate of HFC-245cb and the selectivity of HFO-1234yf were computed from the following formula. The obtained results are shown in Table 3.

In the following calculation formula, (HFC-245cb) _in , (HFC-245cb) _out , (HFO-1234yf) _out and (total) _out are respectively passed through a water trap excluding HFC-245cb and dilution gas in the source gas. This represents the molar ratio calculated from the GC area ratio of HFC-245cb in the outlet gas, HFO-1234yf in the water trap passage outlet gas excluding the dilution gas, and the entire water trap passage outlet gas component. In this example, the calculation was performed assuming that (HFC-245cb) _in = (total) _out .

Conversion of HFC-245cb (mol%) = {1- (HFC-245cb) _out / (HFC-245cb) _in } × 100
Selectivity of HFO-1234yf (mol%) =
(HFO-1234yf) _out / {1- (HFC-245cb) _out / (HFC-245cb) _in } × 100

[Comparative Examples 1 to 10]
The reaction was continuously performed in the same manner as in Example 1 except that the composition of the source gas and the reaction conditions were changed as shown in Table 4. Then, the conversion rate of HFC-134a and the selectivity of HFO-1123 were determined in the same manner as in Example 1. Table 4 shows the obtained results.

  From Tables 1 to 4, Examples 1 to 14 using water vapor as the dilution gas are somewhat inferior in conversion rate compared with Comparative Examples 1 to 10 using nitrogen gas as the dilution gas. I understand that there was.

  From Tables 1 to 4, it can be seen that the lower the molar ratio of HFC-134a in the raw material gas or the higher the internal temperature, the higher the conversion of HFC-134a.

[Example 15]
In the operation of Example 4, the dew point of the gas sample after passing through the hydrogen fluoride trap 3 was measured with a dew point meter (manufactured by Vaisala Co., Ltd.), and the moisture content in the gas was calculated. As a result, the water content 90.0 vol% calculated from the supply amount before passing through the reactor 2 was 3.9 vol% (dew point: 24.8 ° C.) after passing through the hydrogen fluoride trap 3. From the above results, it can be seen that the water vapor used as the dilution gas can be separated by 95.0% or more by heat removal.

[Comparative Example 11]
In the operation of Comparative Example 6, the gas flow rate after passing through the raw material gas supply line, the dilution gas supply line, and the hydrogen fluoride trap 3 was measured with a dry gas meter (manufactured by Shinagawa Co., Ltd.). As a result, the gas flow rate calculated from the total gas flow rate of the source gas and the dilution gas supply line was 0.264 mol / h, but after passing through the hydrogen fluoride trap 3, it was 0.262 mol / h. From the above results, it can be seen that it is difficult to separate N ₂ used as a dilution gas by heat removal.

  According to the production method of the present invention, HFO can be efficiently and stably produced from HFC. Further, it is useful as an industrial production method because water vapor as a dilution gas can be separated and recovered and reused.

  DESCRIPTION OF SYMBOLS 1 ... Reaction apparatus, 2 ... Reactor, 3 ... Hydrogen fluoride trap, 4 ... Water trap, 5 ... Metal catalyst, 6 ... Preheating mixer, 7 ... Raw material gas supply line, 8 ... HFC supply line, 9 ... Steam supply Line 10, reactor outlet line 11, outlet line 12, outlet line 13, dehydrator, 14 sampling bag, 15 analyzer

Claims (10)

In the presence of water vapor, the hydrofluorocarbon represented by the following formula (1) is brought into contact with a metal catalyst to convert it into a hydrofluoroolefin represented by the following formula (2). A reaction step of obtaining a first gas composition containing;
Separating the water vapor from the first gas composition to obtain a second gas composition containing the hydrofluoroolefin, and
A method for producing a hydrofluoroolefin, wherein a molar ratio (hydrofluorocarbon / water vapor) of the hydrofluorocarbon and the water vapor supplied to the reaction step is 0.5 / 99.5 or more and 80/20 or less.
CR ¹ R ² X ¹ CR ³ R ⁴ X ² (1)
CR ¹ R ² = CR ³ R ⁴ (2)
(In the above formula (1) and formula (2), R ^{1 to} R ³ are each independently a hydrogen atom or a fluorine atom, and R ⁴ is a hydrogen atom, a fluorine atom, CH ₃ , CH ₂ F, CHF _2. Or CF ₃ , the total number of fluorine atoms of R ^{1 to} R ⁴ is 1 or more, and the total number of hydrogen atoms of R ^{1 to} R ⁴ is 1 or more, one of X ¹ and X ² is hydrogen An atom and the other is a fluorine atom.)   The separation step includes a step of liquefying and separating the water vapor contained in the first gas composition at a pressure of −0.1 MPa to 2.0 MPa and a temperature of −30 ° C. to 210 ° C. The method for producing a hydrofluoroolefin according to claim 1.   The method for producing a hydrofluoroolefin according to claim 1 or 2, wherein the hydrofluorocarbon is 1,1,1,2-tetrafluoroethane, and the hydrofluoroolefin is trifluoroethylene.   The hydrofluorocarbon is 1,1,1,2,2-pentafluoropropane and / or 1,1,1,2,3-pentafluoropropane, and the hydrofluoroolefin is 2,3,3,3-tetra The method for producing a hydrofluoroolefin according to claim 1 or 2, which is a fluoropropene.   The said metal catalyst is a manufacturing method of the hydrofluoroolefin of any one of Claims 1-4 containing at least 1 sort (s) selected from the group which consists of a metal, a metal oxide, and a metal halide.   The metal catalyst includes iron, zinc, cobalt, nickel, palladium, platinum, iridium, rhodium, ruthenium, chromium oxide, aluminum oxide, zinc oxide, zirconium oxide, niobium oxide, tin oxide, titanium oxide, iron oxide fluoride, fluorine. The method for producing a hydrofluoroolefin according to any one of claims 1 to 5, comprising at least one selected from the group consisting of aluminum chloride, aluminum chloride, chromium fluoride, chromium chloride and silicon oxide.   The method for producing a hydrofluoroolefin according to any one of claims 1 to 6, wherein the metal catalyst is in a solid state.   The method for producing hydrofluoroolefin according to any one of claims 1 to 7, wherein the hydrofluorocarbon and the water vapor to be supplied to the reaction step are preheated and then supplied to the reactor.   The method for producing a hydrofluoroolefin according to claim 8, wherein the hydrofluorocarbon supplied to the reaction step and the water vapor are mixed and then preheated.   The method for producing a hydrofluoroolefin according to any one of claims 1 to 9, wherein a temperature at which the hydrofluorocarbon is converted to the hydrofluoroolefin is 200 ° C or higher and 1200 ° C or lower.

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