Method for producing difluoroethylene

Abstract

The present invention provides a method for obtaining HFO-1132 (E) and / or HFO-1132 (Z) more efficiently than conventional methods. Specifically, the present invention provides a method for producing a composition containing HFO-1132 (E) and / or HFO-1132 (Z), the method comprising: (x) supplying a raw material gas containing 1, 1, 2-trifluoroethane (HFC-143), trans-1, 2-difluoroethylene (HFO-1132 (E)) and / or cis-1, 2-difluoroethylene (HFO-1132 (Z)), and a diluent gas to a reactor filled with a catalyst; and a step for obtaining a reaction product containing HFO-1132 (E) and HFO-1132 (Z) by performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132 (E) and HFO-1132 (Z), in which the content of the diluent gas in the raw material gas is 1-80 mol%.

Description

Technical Field

[0001] The present invention relates to a method for producing difluoroethylene. Background Art

[0002] Non-patent document 1 discloses a method of isomerizing HFO-1132(Z) to HFO-1132(E) by contacting HFO-1132(Z) in a gas phase using iodine as a catalyst. In addition, patent document 1 discloses a method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), which comprises:

[0003] (x) a step of supplying a composition containing HFC-143 and HFO-1132(E) and / or HFO-1132(Z) to a reactor filled with a catalyst, and performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z) to obtain a composition containing HFO-1132(E) and HFO-1132(Z);

[0004] (y) a step of separating the reaction product obtained in the above step (x) into a first material stream containing HFO-1132(E) as a main component and a second material stream containing HFO-1132(Z) as a main component; and

[0005] (z) The first material stream or the second material stream obtained in the step (y) is recycled in the step (x) and supplied to the isomerization reaction step.

[0006] Prior art literature

[0007] Non-patent literature

[0008] Non-patent document 1: Journal of the American Chemical Society, 1961, vol. 83, 3047

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2019-214535 Summary of the invention

[0011] Technical problem to be solved by the invention

[0012] The technical problem to be solved by the present invention is to provide a method for efficiently obtaining HFO-1132(E) and / or HFO-1132(Z).

[0013] Technical solutions for solving technical problems

[0014] Item 1. A method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), comprising: (x) supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143), trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) and a diluent gas to a reactor filled with a catalyst, and performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z) to obtain a reaction product containing HFO-1132(E) and HFO-1132(Z), wherein the content of the diluent gas in the raw material gas is 1 to 80 mol%.

[0015] Item 2. A method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), comprising: (x) supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143) and trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) to a reactor filled with a catalyst to defluorinate HFC-143; A process for obtaining a reaction product containing HFO-1132(E) and HFO-1132(Z) by a hydrogenation reaction and an isomerization reaction between HFO-1132(E) and HFO-1132(Z), in which the contact time represented by the ratio W / Fo of the catalyst filling amount W(g) to the flow rate Fo (flow rate at 0°C and 1 atm: cc / sec) of the above-mentioned raw material gas is 0.1 to 10 g·sec / cc.

[0016] Item 3. The manufacturing method according to Item 1 above, wherein the diluent gas is selected from HF gas, O 2 Gas, CO 2 Gas and N 2 At least one of the gases.

[0017] Item 4. The production method as described in Item 1 or 2 above further includes: (y) a step of separating the reaction product obtained in the above step (x) into a first material flow containing HFO-1132 (E) as a main component and a second material flow containing HFO-1132 (Z) as a main component.

[0018] Item 5. The manufacturing method as described in Item 4 above further includes: (z) recycling the first material flow or the second material flow obtained in the above step (y) in the above step (x) for the above isomerization reaction.

[0019] Effects of the Invention

[0020] According to the present invention, HFO-1132(E) and / or HFO-1132(Z) can be obtained more efficiently than the conventional method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a diagram schematically showing the production process of HFO-1132(E) of Examples 1 to 12. DETAILED DESCRIPTION

[0022] The technical problem to be solved by the present invention is to provide a method for obtaining HFO-1132(E) and / or HFO-1132(Z) more efficiently than the existing method, which is a method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), the production method comprising: supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143) and trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) to a reactor filled with a catalyst, performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z), thereby obtaining a reaction product containing HFO-1132(E) and HFO-1132(Z).

[0023] In order to solve the above technical problems, the inventors of the present invention have conducted intensive research and found that the above technical problems can be solved by using a method of using a raw material gas containing a specific amount of diluent gas, or by setting the contact time represented by the ratio of the catalyst filling amount W (g) to the flow rate Fo (flow rate at 0°C and 1 atmosphere: cc / sec) of the raw material gas to a specific range. The present invention is based on such a viewpoint and is completed through further research, and the present invention includes the following aspects.

[0024] The method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z) of the present invention can be roughly divided into the following two embodiments.

[0025] (Implementation 1: Method using dilution gas)

[0026] A method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), comprising: (x) supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143), trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) and a diluent gas to a reactor filled with a catalyst, and performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z) to obtain a reaction product containing HFO-1132(E) and HFO-1132(Z), wherein the content of the diluent gas in the raw material gas is 1 to 80 mol%.

[0027] (Embodiment 2: Method with a specific W / Fo ratio)

[0028] A method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), comprising: (x) supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143) and trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) to a reactor filled with a catalyst, and performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z) to obtain a reaction product containing HFO-1132(E) and HFO-1132(Z), wherein the contact time represented by the ratio W / Fo of the catalyst filling amount W (g) to the flow rate Fo (flow rate at 0°C and 1 atm: cc / sec) of the raw material gas is 0.1 to 10 g·sec / cc.

[0029] Hereinafter, first, terms common to Embodiments 1 and 2 are described, and then Embodiments 1 and 2 are described separately.

[0030] 1. Explanation of terms

[0031] 1.1. Isomerization reaction

[0032] The isomerization reaction refers to the isomerization reaction between HFO-1132(E) and HFO-1132(Z). The isomerization reaction follows the following reaction formula. The thermodynamic stability of HFO-1132(E) is lower than that of HFO-1132(Z), so the equilibrium is tilted toward the HFO-1132(Z) side. By subjecting a composition containing HFO-1132(E) and / or HFO-1132(Z) to the isomerization reaction, the reaction proceeds in a manner close to the content ratio of HFO-1132(E) and HFO-1132(Z) in the equilibrium state. The content ratio depends on the temperature. The higher the temperature at which the reaction is performed, the less HFO-1132(Z) is and the more HFO-1132(E) is increased.

[0033]

[0034] 1.2. HFO-1132(E) and / or HFO-1132(Z) and compositions containing the same

[0035] HFO-1132(E) and / or HFO-1132(Z) used as an isomerization raw material may contain other components. There are no particular limitations on the other components as long as they do not significantly inhibit the isomerization reaction.

[0036] Examples of other components include impurities mixed in the process of obtaining the composition containing HFO-1132(E) and / or HFO-1132(Z), by-products generated, etc. The mixed impurities include impurities contained in the raw materials used to obtain the above composition.

[0037] Examples of methods for obtaining a composition containing HFO-1132(E) and / or HFO-1132(Z) to be used as an isomerization raw material include a method of subjecting halogenated ethane to a dehydrohalogenation reaction or a dehalogenation reaction.

[0038] The halogenated ethane used in such a reaction is not particularly limited and can be widely selected. As specific examples, the following halogenated ethanes can be cited. These halogenated ethanes are widely used in applications such as refrigerants, solvents, foaming agents, and propellants and are usually available.

[0039] 1,1,2-Trifluoroethane (CHF 2 CH 2 F; HFC-143)

[0040] 1-Bromo-1,2-difluoroethane (CHFBrCH 2 F)

[0041] 1-Chloro-1,2-difluoroethane (CHClFCH 2 F)

[0042] 1,2-Dichloro-1,2-difluoroethane (CHClFCHClF)

[0043] 1,1,2,2-Tetrafluoroethane (CHF 2 CHF 2 )

[0044] 1-Chloro-1,2,2-trifluoroethane (CHClFCHF 2 )

[0045] 1.3. Dehydrohalogenation of ethane halides

[0046] The dehydrohalogenation reaction of the ethane halides is preferably carried out in the presence of a catalyst. The catalyst is not particularly limited and can be selected from a wide range.

[0047] As a catalyst, a known catalyst that can be used in a dehydrohalogenation reaction can be used. For example, halides, oxides and oxidized halides of transition metals, group 14 elements and group 15 elements, as well as Mg, Al, etc. can be exemplified. As specific examples of transition elements, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ta and W can be cited. As specific examples of group 14 elements, Sn and Pb can be cited. As specific examples of group 15 elements, Sb and Bi can be cited.

[0048] Examples of the halides of these elements include fluorides and chlorides.

[0049] Among these, SbCl is an example of a preferred catalyst. 5 、SbCl 3 , SbF 5 、TaCl 5 SnCl 4 、NbCl 5 、FeCl 3 CrCl 3 ,CrF 3 、TiCl 4 、MoCl 5 Cr 2 O 3 CrO 2 CrO 3 、CoCl 2 、NiCl 2 MgF 2 , AlOF (aluminum oxyfluoride), CrOF (chromium oxyfluoride), etc.

[0050] These catalysts can be used alone or in combination of two or more, or can be supported by a carrier. The carrier is not particularly limited, and examples thereof include porous aluminum silicate represented by zeolite, aluminum oxide, silicon oxide, activated carbon, titanium oxide, zirconium oxide, zinc oxide, aluminum fluoride, etc. Among these, one can be used, or a mixture of two or more can be used, or a composite material can be used. Specific examples of catalysts supported by a carrier include Cr 2 O 3 / Al 2 O 3 Cr 2 O 3 / AlF 3 Cr 2 O 3 / C、CoCl 2 / Cr 2 O 3 / Al 2 O 3 、NiCl 2 / Cr 2 O 3 / Al 2 O 3 、CoCl 2 / AlF 3 、NiCl 2 / AlF 3 wait.

[0051] As the catalyst, a catalyst containing a chromium atom is preferably used, and chromium oxide is particularly preferred. Examples of chromium oxide include crystalline chromium oxide and amorphous chromium oxide, and fluorinated chromium oxides are particularly preferred.

[0052] As a specific example of a method for obtaining a composition containing HFO-1132(E) and / or HFO-1132(Z) by subjecting ethane halide to a dehydrohalogenation reaction, HFC-143 as a raw material is subjected to a temperature of 400° C. for a contact time W / F O (cat. / ml·s) = 60 seconds, 15 mol% O 2 A method of contacting with chromium oxyfluoride as a catalyst under an atmosphere, etc.

[0053] 1.4. Dehalogenation of ethane halides

[0054] The dehalogenation reaction of the above-mentioned ethane halide can be carried out according to a known method. For example, the dehalogenation reaction can be carried out by reacting with a metal reagent such as an organic magnesium compound or zinc in an aprotic solvent. As a specific example, by reacting 1-bromo-1,2,2-fluoroethane with zinc powder in an aprotic solvent to remove FBr, a composition containing HFO-1132(E) and / or HFO-1132(Z) can be obtained.

[0055] The reaction temperature of the dehalogenation reaction is not particularly limited and can be appropriately set, and can be, for example, -20°C to 200°C, and preferably 0°C to 80°C.

[0056] The metal reagent that can be used in the dehalogenation reaction is not particularly limited and can be appropriately set. For example, zinc, magnesium, nickel, etc. can be used. Zinc is particularly preferred.

[0057] 2. Implementation method 1 (method using dilution gas)

[0058] The method for producing difluoroethylene according to the first embodiment is a method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), comprising:

[0059] (x) a step of supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143), trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) and a diluent gas to a reactor filled with a catalyst, and performing a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z) to obtain a reaction product containing HFO-1132(E) and HFO-1132(Z), wherein the content of the diluent gas in the raw material gas is 1 to 80 mol%.

[0060] In the method of embodiment 1, in step (x), a raw material gas containing HFC-143, HFO-1132(E) and / or HFO-1132(Z) and a diluent gas is supplied to a reactor filled with a catalyst to carry out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z), thereby obtaining a composition containing HFO-1132(E) and HFO-1132(Z). In the method of embodiment 1, the content of the diluent gas in the raw material gas is 1 to 80 mol%, so that in the subsequent step (y), the first material flow containing HFO-1132(E) as the main component and the second material flow containing HFO-1132(Z) as the main component can be separated more easily. Therefore, the production method of the present invention can obtain the desired isomer of HFO-1132 more efficiently than the production method of the prior art.

[0061] 2.1. catalyst

[0062] As the catalyst, for example, halides, oxides and oxyhalides of transition metals, Group 14 elements and Group 15 elements, and Mg, Al, etc. can be cited. Specific examples of transition elements include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ta, W, etc. Specific examples of Group 14 elements include Sn, Pb, etc. Specific examples of Group 15 elements include Sb, Bi, etc.

[0063] Examples of the halides of these elements include fluorides and chlorides.

[0064] Among these, SbCl is an example of a preferred catalyst. 5 、SbCl 3 , SbF 5 、TaCl 5 SnCl 4 、NbCl 5 、FeCl 3 CrCl 3 ,CrF 3 、TiCl 4 、MoCl 5 Cr 2 O 3 CrO 2 CrO 3 、CoCl 2 、NiCl 2 MgF 2 , AlOF (aluminum oxyfluoride), CrOF (chromium oxyfluoride), etc.

[0065] These catalysts can be used alone or in combination of two or more, or can be supported by a carrier. The carrier is not particularly limited, and examples thereof include porous aluminum silicate represented by zeolite, aluminum oxide, silicon oxide, activated carbon, titanium oxide, zirconium oxide, zinc oxide, aluminum fluoride, etc. Among these, one can be used, or a mixture of two or more can be used, or a composite material can be used. Specific examples of catalysts supported by a carrier include Cr 2 O 3 / Al 2 O 3 Cr 2 O 3 / AlF 3 Cr 2 O 3 / C、CoCl 2 / Cr 2 O 3 / Al 2 O 3 、NiCl 2 / Cr 2 O 3 / Al 2 O 3 、CoCl 2 / AlF 3 、NiCl 2 / AlF 3 wait.

[0066] As the catalyst, a catalyst containing a chromium atom is preferably used, and chromium oxide is particularly preferred. Examples of chromium oxide include crystalline chromium oxide and amorphous chromium oxide, and fluorinated chromium oxides are particularly preferred.

[0067] 2.2. Reactor

[0068] The reactor filled with the catalyst may be a fixed bed or fluidized bed reactor filled with the above catalyst, and the catalyst may be in the form of pellets, powder, granules or the like.

[0069] 2.3. Raw gas

[0070] In the method of embodiment 1, when a raw material gas containing HFC-143, HFO-1132(E) and / or HFO-1132(Z) and a diluent gas is supplied to a reactor, the content of the diluent gas in the raw material gas is 1 to 80 mol%. The content of HFC-143, HFO-1132(E) and / or HFO-1132(Z) in the raw material gas can be arbitrarily set.

[0071] By making the content of the diluent gas in the raw material gas 1 to 80 mol%, the generation of by-products in step (x) can be suppressed. The details of the diluent gas will be described later. For example, by using HF gas as the diluent gas, the generation of HFC-143a (generated as a by-product) in step (x) can be suppressed compared to the case where no diluent gas is used. It is difficult to separate HFC-143a from HFO-1132 (E). Therefore, if HF gas is used as the diluent gas to suppress their generation, in the subsequent step (y), it is easier to separate the first material flow with HFO-1132 (E) as the main component and the second material flow with HFO-1132 (Z) as the main component.

[0072] In addition, when using HF gas (hydrogen fluoride gas), O 2 Gas (oxygen), CO 2 Gas (carbon dioxide gas) and N 2 When at least one of the following gases (nitrogen) is used as the diluent gas, the catalyst degradation can be effectively suppressed in step (x), and the amount of HFO-1132(E) and / or HFO-1132(Z) generated can be maintained for a long period of time. 2 When comparing the case where the diluent gas was used with the case where no diluent gas was used, the conversion rate of HFC-143 in step (x) began to decrease immediately after the reaction started when no diluent gas was used, but it decreased significantly when the diluent gas was used. 2 In the case of gas, a good conversion rate can be maintained for more than 100 hours.

[0073] The preferred content of the diluent gas in the raw gas is 4 to 70 mol%, and the more preferred content is 40 to 65 mol%. In particular, by setting the content to 40 to 65 mol%, the catalyst life is easily extended. This is not limited by theory, but is considered to be due to the effective suppression of the generation of polymers and / or tar.

[0074] In the method of Embodiment 1, HF gas, O 2 Gas, CO 2 Gas, N 2 Gas, helium, argon, etc., especially from the perspective of cost, N 2 In addition, from the perspective described later, HF gas, O 2 Gas and CO 2 Gas is used as the preferred dilution gas.

[0075] When HF gas is used as the diluent gas, in the subsequent step (y), when the first material flow having HFO-1132(E) as the main component and the second material flow having HFO-1132(Z) as the main component are separated, even if the HF contained in the second material flow having HFO-1132(Z) as the main component is not completely separated, it can be recycled in the step (x) as a material flow containing an appropriate desired amount of HF. Thus, the equipment and running costs of the step (y) can be reduced compared to the case where HF gas is not used.

[0076] In addition, the diluent gas contains O 2 In the case of gas, O 2 The molar concentration of HFO-1132(E) and / or HFO-1132(Z) is not limited, but the effect of extending the catalyst life can be further improved by setting the molar concentration relative to the total molar concentration of HFO-1132(E) and / or HFO-1132(Z) and HFC-143 to preferably 5 mol% or more, more preferably 10 mol% or more. 2 Gas can also improve the effect of extending the life of the catalyst. In other words, chlorine can also be used as a diluent gas.

[0077] In addition, the diluent gas contains CO 2 In the case of gas, CO 2 The molar concentration of HFO-1132(E) and / or HFO-1132(Z) is not limited, but by setting the molar concentration relative to the total of HFO-1132(E) and / or HFO-1132(Z) and HFC-143 to preferably 30 mol% or more, more preferably 50 mol% or more, the combustibility of the raw gas, the gas containing the reaction product, and the gas in the system supplied to the separation step can be reduced. 2 The concentration can be arbitrarily adjusted to reduce the combustibility of the gas in the process system and to render it incombustible, and can also be appropriately determined from the viewpoint of the yield of the target product in the separation step.

[0078] 2.4. Reaction conditions

[0079] In step (x), a composition containing HFO-1132(E) and HFO-1132(Z) is obtained by carrying out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z). Among them, HFO-1132(E) and / or HFO-1132(Z) can be obtained by the dehydrofluorination reaction of HFC-143. In step (x), the dehydrofluorination reaction and the isomerization reaction are carried out in the same reactor or in one step. In addition, in step (x) of the present invention, the above two reactions are basically carried out in the same reactor, but for engineering reasons, when it is difficult to use the reactor in practice due to the large size of the reactor or the length of the reactor, a plurality of reactors controlled under the same reaction conditions can be arranged in parallel, and the raw material gas of the same composition can be supplied to each reactor instead of the same reactor (1 reactor). Such a method is called "one step" (the same also in Embodiment 2 described later).

[0080] The dehydrofluorination reaction and the isomerization reaction can be any mode of continuous or intermittent, and preferably continuous from the aspect of improving manufacturing efficiency. In addition, the two reactions can be carried out in any mode of liquid phase reaction or gas phase reaction, preferably gas phase reaction. The following pressure and contact time conditions are the conditions of gas phase reaction.

[0081] The reaction temperature of the two reactions in step (x) is not limited, but is preferably in the range of 200°C to 500°C, more preferably in the range of 300°C to 450°C.

[0082] The pressure of the reactor is not particularly limited and can be set appropriately. When the pressure is high, the formation of polymers such as tar is promoted, so an appropriate pressure can be set. It can usually be set in the range of normal pressure to 0.2 MPaG, preferably in the range of normal pressure to about 0.1 MPaG. In addition, unless otherwise specified, the pressure value in the present invention refers to the gauge pressure (with "G" marked at the end of the unit).

[0083] The reaction time can be appropriately set and is not particularly limited. When the contact time is extended, the conversion rate can be improved, but due to the increase in the amount of catalyst and the increase in equipment, the efficiency is low, so it is necessary to select an appropriate contact time. Usually, the contact time represented by the ratio of the catalyst filling amount W (g) to the flow rate Fo of the raw gas flowing in the reaction system (flow rate at 0°C and 1 atmosphere: cc / sec): W / Fo is preferably about 0.01 to 80 g·sec / cc, wherein it is more preferably about 0.5 to 50 g·sec / cc, and further preferably about 1 to 15 g·sec / cc. By setting it to such a range, it is easy to suppress the formation of by-products.

[0084] 2.5. Process (y)

[0085] In the method of embodiment 1, a step (y) of separating the reaction product obtained in step (x) into a first material stream having HFO-1132 (E) as a main component and a second material stream having HFO-1132 (Z) as a main component may be included. For example, specifically, the reactor outlet gas generated by the isomerization reaction in step (x) is cooled to liquefy, and then distilled to separate into a first material stream having HFO-1132 (E) as a main component and a second material stream having HFO-1132 (Z) as a main component. Among them, in the first material stream having HFO-1132 (E) as a main component, HFO-1132 (E) is contained in all organic substances in the first material stream by more than 30 mol%, preferably by more than 50 mol%. In addition, in the second material stream having HFO-1132 (Z) as a main component, HFO-1132 (Z) is contained in all organic substances in the second material stream by more than 30 mol%, preferably by more than 50 mol%.

[0086] The first material stream may contain, in addition to the target HFO-1132(E), HFC-143a etc. generated by the rearrangement reaction of HFC-143 for obtaining a composition containing HFO-1132(E) and / or HFO-1132(Z). In this case, HFO-1132(E) may be separated by a separate method such as distillation.

[0087] 2.6. Process (z)

[0088] The method of Embodiment 1 may include a step (z) of recycling the first material stream or the second material stream obtained in the step (y) in the step (x) to provide the first material stream or the second material stream for the isomerization reaction.

[0089] In the method of embodiment 1, in order to recover a composition having a further increased content ratio of either HFO-1132(E) or HFO-1132(Z), it is preferred that the method further include a step of recovering a material flow different from the material flow recycled in the above step (z) from the first material flow and the second material flow obtained in the above step (y). For example, a step of recycling the first material flow and recovering the second material flow in the above step (z) can be cited.

[0090] 3. Embodiment 2 (Specific W / Fo ratio embodiment)

[0091] The method for producing difluoroethylene according to the second embodiment is a method for producing a composition containing HFO-1132(E) and / or HFO-1132(Z), comprising:

[0092] (x) A step of supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143) and trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)) to a reactor filled with a catalyst to carry out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z) to obtain a reaction product containing HFO-1132(E) and HFO-1132(Z), wherein the contact time represented by the ratio W / Fo of the catalyst filling amount W (g) to the flow rate Fo (flow rate at 0°C and 1 atm: cc / sec) of the raw material gas is 0.1 to 10 g·sec / cc.

[0093] In the method of embodiment 2, in step (x), a raw material gas containing HFC-143, HFO-1132(E) and / or HFO-1132(Z) is supplied to a reactor filled with a catalyst to carry out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z), thereby obtaining a composition containing HFO-1132(E) and HFO-1132(Z). In the method of embodiment 2, the contact time represented by the ratio of the catalyst filling amount W(g) to the flow rate Fo (flow rate at 0°C and 1 atmosphere: cc / sec) of the above-mentioned raw material gas is 0.1 to 10 g·sec / cc, thereby suppressing the formation of by-products. In particular, it is possible to suppress the generation of CO, CO 2 , HFC-143a, etc., and in the subsequent step (y), when separating the first material stream containing HFO-1132(E) as the main component and the second material stream containing HFO-1132(Z) as the main component, the accompanying CO, CO 2 Therefore, the production method of the present invention can obtain the desired isomer of HFO-1132 more efficiently than the production method of the prior art.

[0094] 3.1. catalyst

[0095] As the catalyst, for example, halides, oxides and oxyhalides of transition metals, Group 14 elements and Group 15 elements, and Mg, Al, etc. can be cited. Specific examples of transition elements include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Zr, Nb, Ta, W, etc. Specific examples of Group 14 elements include Sn, Pb, etc. Specific examples of Group 15 elements include Sb, Bi, etc.

[0096] Examples of the halides of these elements include fluorides and chlorides.

[0097] Among these, SbCl is an example of a preferred catalyst. 5 、SbCl 3 , SbF 5 、TaCl 5 SnCl 4 、NbCl 5 、FeCl 3 CrCl 3 ,CrF 3 、TiCl 4 、MoCl 5 Cr 2 O 3 CrO 2 CrO 3 、CoCl 2 、NiCl 2 MgF 2 , AlOF (aluminum oxyfluoride), CrOF (chromium oxyfluoride), etc.

[0098] These catalysts can be used alone or in combination of two or more, or can be supported by a carrier. The carrier is not particularly limited, and examples thereof include porous aluminum silicate represented by zeolite, aluminum oxide, silicon oxide, activated carbon, titanium oxide, zirconium oxide, zinc oxide, aluminum fluoride, etc. Among these, one can be used, or a mixture of two or more can be used, or a composite material can be used. Specific examples of catalysts supported by a carrier include Cr 2 O 3 / Al 2 O 3 Cr 2 O 3 / AlF 3 Cr 2 O 3 / C、CoCl 2 / Cr 2 O 3 / Al 2 O 3 、NiCl 2 / Cr 2 O 3 / Al 2 O 3 、CoCl 2 / AlF 3 、NiCl 2 / AlF 3 wait.

[0099] As the catalyst, a catalyst containing a chromium atom is preferably used, and chromium oxide is particularly preferred. Examples of chromium oxide include crystalline chromium oxide and amorphous chromium oxide, and fluorinated chromium oxides are particularly preferred.

[0100] 3.2. Reactor

[0101] The reactor filled with the catalyst may be a fixed bed or fluidized bed reactor filled with the above catalyst, and the catalyst may be in the form of pellets, powder, granules or the like.

[0102] 3.3. Raw gas

[0103] In the method of Embodiment 2, a raw material gas containing HFC-143, HFO-1132(E) and / or HFO-1132(Z) is used. The content of HFC-143, HFO-1132(E) and / or HFO-1132(Z) in the raw material gas can be set arbitrarily. In addition, the raw material gas can also be diluted with a diluent gas.

[0104] As diluent gas, HF gas, O 2 Gas, CO 2 Gas, N 2 Gas, helium, argon, etc., especially from the perspective of cost, N 2 gas.

[0105] By including a diluent gas in the raw gas, the generation of by-products can be suppressed, and in step (x), the degradation of the catalyst can be effectively suppressed. This is not subject to theoretical constraints, and it is considered to be due to the effective suppression of the generation of polymers and / or tar. The molar concentration of the diluent gas in the raw gas is preferably 0.01 to 3.0 mol%, more preferably 0.1 to 2.0 mol%, and further preferably 0.2 to 1.0 mol% relative to the total molar concentration of HFO-1132 (E) and / or HFO-1132 (Z) and HFC-143. In addition, when using O as the diluent gas, 2 In the case of chlorine or chlorine gas, the effect of extending the life of the catalyst can be further improved. In other words, chlorine gas can also be used as a diluent gas.

[0106] The diluent gas contains CO 2 In the case of gas, CO 2The molar concentration of HFO-1132(E) and / or HFO-1132(Z) is not limited, but by setting the molar concentration relative to the total of HFO-1132(E) and / or HFO-1132(Z) and HFC-143 to preferably 30 mol% or more, more preferably 50 mol% or more, the combustibility of the raw gas, the gas containing the reaction product, and the gas in the system supplied to the separation step can be reduced. 2 The concentration can be arbitrarily adjusted in order to reduce the combustibility of the gas in the process system and to make it incombustible, and can also be appropriately determined from the perspective of the yield of the target product in the separation step.

[0107] 3.4. Reaction conditions

[0108] In step (x), a composition containing HFO-1132(E) and HFO-1132(Z) is obtained by carrying out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z). Among them, HFO-1132(E) and / or HFO-1132(Z) can be obtained by the dehydrofluorination reaction of HFC-143. In step (x), the dehydrofluorination reaction and the isomerization reaction are carried out in the same reactor or in one step. The two reactions can be either continuous or intermittent. From the perspective of improving manufacturing efficiency, a continuous method is preferably used. In addition, embodiment 2 is a gas phase reaction.

[0109] In the method of Embodiment 2, when the raw material gas is supplied to the reactor, the contact time represented by the ratio of the catalyst filling amount W (g) to the flow rate Fo of the raw material gas (flow rate at 0°C and 1 atmosphere: cc / sec): W / Fo is set in the range of 0.1 to 10 g·sec / cc. This can suppress the generation of by-products in step (x). In particular, CO and CO 2 , HFC-143a, etc., and in the subsequent step (y), when separating the first material stream containing HFO-1132(E) as the main component and the second material stream containing HFO-1132(Z) as the main component, the accompanying CO, CO 2 , HFC-143a, etc. Thus, the production method of the present invention can obtain the desired isomer of HFO-1132 more efficiently than the production method of the prior art. The contact time represented by W / Fo can be in the range of 0.1 to 10 g·sec / cc, preferably in the range of 1 to 5 g·sec / cc. By setting it in such a range, it is easy to further suppress the generation of by-products.

[0110] The reaction temperature of the two reactions in step (x) is not limited, but is preferably in the range of 200°C to 500°C, more preferably in the range of 300°C to 450°C.

[0111] The pressure of the reactor is not particularly limited and can be set appropriately. When the pressure is high, the production of polymers such as tar is promoted, so an appropriate pressure can be set. Usually, it can be set in the range of normal pressure to 0.2 MPaG, preferably normal pressure to 0.1 MPaG.

[0112] 3.5. Process (y)

[0113] In the method of embodiment 2, a step (y) of separating the reaction product obtained in step (x) into a first material stream having HFO-1132 (E) as a main component and a second material stream having HFO-1132 (Z) as a main component may be included. For example, specifically, the reactor outlet gas generated by the isomerization reaction in step (x) is cooled to liquefy, and then distilled to separate into a first material stream having HFO-1132 (E) as a main component and a second material stream having HFO-1132 (Z) as a main component. In addition, in the first material stream having HFO-1132 (E) as a main component, the total organic matter in the first material stream contains 30 mol% or more of HFO-1132 (E), preferably 50 mol% or more. In addition, in the second material stream having HFO-1132 (Z) as a main component, the total organic matter in the second material stream contains 30 mol% or more of HFO-1132 (Z), preferably 50 mol% or more.

[0114] The first material stream may contain, in addition to the target HFO-1132(E), HFC-143a etc. generated by the rearrangement reaction of HFC-143 for obtaining a composition containing HFO-1132(E) and / or HFO-1132(Z). In this case, HFO-1132(E) may be separated by a separate method such as distillation.

[0115] 3.6. Process (z)

[0116] The method of Embodiment 2 may include a step (z) of recycling the first material stream or the second material stream obtained in the step (y) in the step (x) to provide the first material stream or the second material stream for the isomerization reaction.

[0117] In the method of Embodiment 2, in order to recover a composition having a further increased content ratio of either HFO-1132(E) or HFO-1132(Z), it is preferred that the method further include a step of recovering a material flow different from the material flow recycled in the above step (z) from the first material flow and the second material flow obtained in the above step (y). For example, a step of recycling the first material flow and recovering the second material flow in the above step (z) can be cited.

[0118] Example

[0119] Hereinafter, the present invention will be described with reference to Examples, but the present invention is not limited to these Examples.

[0120] <Examples 1 to 12>

[0121] A process is constructed, the process comprising: supplying a raw material gas containing HFC-143 and HFO-1132(Z) to a reactor filled with a catalyst, subjecting it to a dehydrofluorination reaction and an isomerization reaction, thereby obtaining a composition containing HFO-1132(E) and HFO-1132(Z) (step (x)); sending the raw material gas to a separation step, separating it into a first material flow containing HFO-1132(E) as a main component and a second material flow containing HFO-1132(Z) as a main component (step (y)); and recycling the second material flow in step (x) (step (z)).

[0122] (1) Dehydrofluorination reaction and isomerization reaction (step (x))

[0123] According to the reaction conditions shown in Tables 1 and 2, each raw gas (marked by the inlet composition) was supplied to the dehydrofluorination reaction and the isomerization reaction to obtain a composition containing HFO-1132 (E) and HFO-1132 (Z) (marked by the outlet organic composition) (step (x)). The reactor had an outer diameter of 12.7 mm and a length of 700 mm, and was filled with 10 g of the chromium oxide catalyst obtained according to the following preparation steps to carry out the above reaction.

[0124] <Chromium oxide catalyst preparation steps>

[0125] 114 g of 10% ammonia water was added to 765 g of 5.7% chromium nitrate aqueous solution, and the obtained precipitate was filtered and washed, and then dried in air at 120°C for 12 hours to obtain chromium hydroxide. The precipitate was formed into pellets with a diameter of 3.0 mm and a height of 3.0 mm, and fired at 400°C for 2 hours in a nitrogen stream. The chromium oxide obtained was determined to be CrO based on the results of quantitative analysis of the Cr content and elemental analysis. 2.0 The chromium oxide pellets were filled into a Hastelloy C reaction tube and 2HF was diluted to 20% by volume, and the temperature was gradually increased from 200° C. to 360° C. using the diluted gas. After reaching 360° C., fluorination was performed with 100% HF for 220 hours to obtain a fluorinated chromium oxide catalyst.

[0126] The results of each step (x) of Examples 1 to 12 are summarized in Tables 1 and 2 as follows.

[0127] Example 1

[0128] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 30.0 / 60.0 / 10.0 / 0.0.

[0129] The reaction temperature was 350°C, and the contact time represented by W / Fo was 10 g·sec / cc.

[0130] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 65.0 / 13.0 / 12.0 / 4.0 / 3.1 / 0.8.

[0131] Example 2

[0132] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / HF is in the order of 28.7 / 57.4 / 9.6 / 4.3.

[0133] The reaction temperature was 350°C, and the contact time represented by W / Fo was 10 g·sec / cc.

[0134] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 64.0 / 12.2 / 15.0 / 2.9 / 2.9 / 0.9.

[0135] Example 3

[0136] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 15.8 / 31.6 / 5.3 / 47.4.

[0137] The reaction temperature was 350°C, and the contact time represented by W / Fo was 10 g·sec / cc.

[0138] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 60.0 / 11.1 / 23.0 / 2.2 / 2.0 / 1.1.

[0139] Example 4

[0140] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 10.7 / 21.4 / 3.6 / 64.3.

[0141] The reaction temperature was 350°C, and the contact time represented by W / Fo was 10 g·sec / cc.

[0142] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 58.0 / 9.5 / 26.0 / 1.6 / 1.8 / 1.1.

[0143] Example 5

[0144] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 10.7 / 21.4 / 3.6 / 64.3.

[0145] The reaction temperature was 350°C, and the contact time represented by W / Fo was 20 g·sec / cc.

[0146] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 57.0 / 9.7 / 24.0 / 2.7 / 2.9 / 1.8.

[0147] Example 6

[0148] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 15.0 / 80.0 / 5.0 / 0.0.

[0149] The reaction temperature was 370°C, and the contact time represented by W / Fo was 10 g·sec / cc.

[0150] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 72.0 / 15.0 / 4.0 / 2.9 / 3.1 / 1.2.

[0151] Example 7

[0152] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 15.0 / 80.0 / 5.0 / 0.0.

[0153] The reaction temperature was 370°C, and the contact time represented by W / Fo was 5 g·sec / cc.

[0154] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 75.0 / 11.0 / 7.0 / 2.0 / 2.2 / 0.8.

[0155] Example 8

[0156] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 15.0 / 80.0 / 5.0 / 0.0.

[0157] The reaction temperature was 370°C, and the contact time represented by W / Fo was 1.5 g·sec / cc.

[0158] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 80.0 / 8.0 / 9.0 / 1.1 / 0.8 / 0.4.

[0159] Example 9

[0160] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 15.0 / 80.0 / 5.0 / 0.0.

[0161] The reaction temperature was 370°C, and the contact time represented by W / Fo was 0.5 g·sec / cc.

[0162] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 81.0 / 6.0 / 11.0 / 0.5 / 0.9 / 0.2.

[0163] Example 10

[0164] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 88.0 / 10.0 / 2.0 / 0.0.

[0165] The reaction temperature was 300°C, and the contact time represented by W / Fo was 3 g·sec / cc.

[0166] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 13.0 / 0.2 / 85.0 / 0.2 / 0.2 / 0.1.

[0167] Embodiment 11

[0168] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / The order of HF is 88.0 / 10.0 / 2.0 / 0.0.

[0169] The reaction temperature was 300°C, and the contact time represented by W / Fo was 7 g·sec / cc.

[0170] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 19.0 / 1.0 / 79.0 / 0.4 / 0.4 / 0.1.

[0171] Example 12

[0172] The inlet composition (mol%) is based on HFC-143 / HFO-1132(Z) / O 2 / N 2 The order is 15.8 / 31.6 / 5.3 / 47.4.

[0173] The reaction temperature was 350°C, and the contact time represented by W / Fo was 10 g·sec / cc.

[0174] The composition of the exported organic matter (mol%) is as follows: HFO-1132(Z) / HFO-1132(E) / HFC-143 / CO / CO 2 / The order of R143a is 59.0 / 11.6 / 20.0 / 2.9 / 2.8 / 0.9.

[0175]

Table 1

[0176]

[0177]

Table 2

[0178]

[0179] The isomerization reaction is carried out using a chromium oxyfluoride catalyst to obtain a reaction product in which the concentration of either isomer of HFO-1132(E) and / or HFO-1132(Z) is increased compared to the supplied raw material composition containing them. 2 When the diluent gas is HF gas, the catalyst degradation can be suppressed and a good conversion rate can be maintained even after the reaction has lasted for 100 hours. 2 Compared with Example 12 using HF gas, it can be seen that Example 3 using HF gas can further suppress CO and CO 2 It can also be seen that compared with Example 1 which does not use HF gas, Example 2 which uses HF gas can suppress the generation of CO, CO 2 The generation of CO (generated as a by-product) can be suppressed, although the amount of suppression is not much. It can also be seen that even when the contact time is as long as in Example 4 (not satisfying the conditions of Embodiment 2), as long as the amount of diluent gas satisfies the conditions of Embodiment 1, the generation of CO (generated as a by-product) can be significantly suppressed. In any embodiment, the generation of by-products is suppressed in step (x), so in the subsequent step (y), it can be easily separated into a first material flow with HFO-1132 (E) as the main component and a second material flow with HFO-1132 (Z) as the main component by distillation.

[0180] (2) Reaction process

[0181] Based on the above results, we build Figure 1 The flow rate (kg / hr) of each component in each material flow is as follows and is also summarized in Table 3. The flow rate of each component in each material flow is HFO-1132(E) / HFO-1132(Z) / HFC-143 / HFC-143a / CO+CO 2 The order of total / HF is:

[0182] F11…0 / 0 / 8.8 / 0 / 0 / 0

[0183] S11…5.6 / 70.9 / 72 / 0.63 / 0.48 / 41.7

[0184] S12…5.6 / 0 / 0 / 0.63 / 0.48 / 0.03

[0185] S13…0 / 70.9 / 72 / 0 / 0 / 41.67

[0186] S14…0 / 70.9 / 72 / 0 / 0 / 39.3

[0187] S15…0 / 0 / 0 / 0 / 0 / 2.4.

[0188] The reaction conditions are reaction temperature 350°C, reaction pressure 0.1 MPaG, W / Fo=6 g·sec / cc. The target product is HFO-1132(E). In addition, the HF gas contained in the material flow is removed by a deacidification device before being transported to the next step, but deacidification can also be carried out by any method such as adsorption, distillation, water washing, etc.

[0189]

Table 3

[0190]

[0191] Explanation of symbols

[0192] A: Reactor for dehydrofluorination reaction and isomerization reaction; B: Distillation column; C: Distillation column.

Claims

1. A method for producing a composition containing trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)), characterized in that: (x) a step of supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143) and HFO-1132(E) and / or HFO-1132(Z) and a diluent gas to a reactor filled with a catalyst to carry out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z), thereby obtaining a reaction product containing HFO-1132(E) and HFO-1132(Z); In this step, the content of the diluent gas in the raw material gas is 1 to 80 mol %.

2. A method for producing a composition containing trans-1,2-difluoroethylene (HFO-1132(E)) and / or cis-1,2-difluoroethylene (HFO-1132(Z)), characterized in that: (x) a step of supplying a raw material gas containing 1,1,2-trifluoroethane (HFC-143) and HFO-1132(E) and / or HFO-1132(Z) to a reactor filled with a catalyst to carry out a dehydrofluorination reaction of HFC-143 and an isomerization reaction between HFO-1132(E) and HFO-1132(Z), thereby obtaining a reaction product containing HFO-1132(E) and HFO-1132(Z); In this process, the contact time represented by the ratio of the catalyst filling amount W to the flow rate Fo of the raw gas: W / Fo is 0.1 to 10 g·sec / cc, where W is in g and Fo is the flow rate at 0°C and 1 atmosphere in cc / sec.

3. The manufacturing method according to claim 1, characterized in that: The dilution gas is at least one selected from HF gas, O2 gas, CO2 gas and N2 gas.

4. The manufacturing method according to claim 1 or 2, characterized in that: The method further comprises the step (y) of separating the reaction product obtained in the step (x) into a first stream containing HFO-1132 (E) as a main component and a second stream containing HFO-1132 (Z) as a main component.

5. The manufacturing method according to claim 4, characterized in that: The method further includes a step (z) of recycling the first material stream or the second material stream obtained in the step (y) in the step (x) to provide the material for the isomerization reaction.

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