An azeotrope-like composition comprising 1,2-difluoroethene or 1,1,2-trifluoroethene and hydrogen fluoride

Abstract

The invention provides novel azeotrope-like compositions and separation processes utilizing the same. An azeotrope-like composition comprising 1,2-difluoroethylene (HFO-1132) and hydrogen fluoride. An azeotrope-like composition comprising 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride. A separation process for a composition comprising at least one member selected from the group consisting of trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)), and 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride.

Description

Technical Field

[0001] The present invention relates to an azeotropic composition comprising 1,2-difluoroethylene or 1,1,2-trifluoroethylene and containing hydrogen fluoride, and a method for separating hydrogen fluoride from the composition. Background Technology

[0002] A thermal cycling working medium characterized by containing 1,2-difluoroethylene (HFO-1132) is known. It is described that because this working medium contains HFO-1132, which has carbon-carbon double bonds and is easily decomposed by OH radicals in the atmosphere, it has little impact on the ozone layer and little impact on global warming (Patent Document 1).

[0003] In addition, as a method for manufacturing 1,1,2-trifluoroethylene (HFO-1123), it is known to be manufactured by dehydrofluorination of 1,1,1,2-tetrafluoroethane (Patent Document 2).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: International Publication No. 2012 / 157765

[0007] Patent Document 2: International Publication No. 2009 / 010472 Summary of the Invention

[0008] The technical problem that the invention aims to solve

[0009] The technical problem of the present invention is to provide a novel azeotropic composition and a separation method using the composition.

[0010] Technical solutions for solving technical problems

[0011] Item 1. An azeotropic composition comprising 1,2-difluoroethylene (HFO-1132) and hydrogen fluoride.

[0012] Item 2. The azeotropic composition as described in Item 1, wherein the HFO-1132 is trans-1,2-difluoroethylene (HFO-1132(E)).

[0013] Item 3. The azeotropic composition as described in Item 1, wherein the above-mentioned HFO-1132 is cis-1,2-difluoroethylene (HFO-1132(Z)).

[0014] Item 4. The azeotropic composition as described in Item 2, having a boiling point of -40°C to 40°C at a pressure of 185 kPa to 2480 kPa.

[0015] Item 5. The azeotropic composition as described in Item 3, having a boiling point of -40°C to 40°C at a pressure of 51 kPa to 1880 kPa.

[0016] Item 6. The azeotropic composition as described in any one of items 1 to 5, comprising:

[0017] 1,2-Difluoroethylene (HFO-1132) and hydrogen fluoride, and

[0018] At least one additional compound selected from 1,1-difluoroethylene (HFO-1132a), 1,1,2-trifluoroethylene (HFO-1123), fluoromethane (HFC-41), 1,1,2,2-tetrafluoroethane (HFC-134) and 1,1,2-trifluoroethane (HFC-143).

[0019] Item 7. An azeotropic composition comprising 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride.

[0020] Item 8. The azeotropic composition as described in Item 7, having a boiling point of -40°C to 40°C at a pressure of 249 kPa to 3480 kPa.

[0021] Item 9. A method for separating a composition comprising at least one selected from trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)) and 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride.

[0022] The separation method includes steps (a) and (b), and may also include step (c) if necessary:

[0023] (a) The process of feeding a composition comprising at least one selected from HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride into a first distillation column;

[0024] (b) The step of taking an azeotropic composition comprising at least one of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride as a first distillate, and taking a composition rich in i) at least one of HFO-1132(E), HFO-1132(Z) and HFO-1123 or ii) hydrogen fluoride at a higher concentration than the supplied composition as the bottom composition of a first distillation column;

[0025] (c) The process of feeding the first distillate to a second distillation column and distilling it at a different pressure than that of the first distillation column.

[0026] The effects of the invention

[0027] According to the present invention, a novel azeotropic composition and a separation method using the composition are provided. Attached Figure Description

[0028] Figure 1 This is a diagram illustrating an example of a separation method using an azeotropic composition.

[0029] Figure 2 This is a diagram illustrating another example of a separation method using an azeotropic composition. Detailed Implementation

[0030] In this specification, the term "quasi-azeotropic composition" refers to a composition that can be viewed substantially the same as an azeotropic composition. Specifically, in this specification, the term "quasi-azeotropic composition" refers to a mixture of two or more substances having a constant boiling point or substantially a constant boiling point, exhibiting substantially the same characteristics as a single substance. One characteristic of a quasi-azeotropic composition is that the composition of the vapor produced by the evaporation or distillation of the liquid does not substantially change with the composition of the liquid. That is, in this specification, a mixture is called a quasi-azeotropic composition when it boils, distills, or refluxes without substantial change in composition. Specifically, in this invention, a composition is defined as a quasi-azeotropic composition when the difference between the bubble point vapor pressure and the dew point vapor pressure of the composition at a specific temperature is 3% or less (based on bubble point pressure).

[0031] One method for manufacturing 1,2-difluoroethylene (HFO-1132) is, for example, the method of manufacturing it by dehydrofluorination of 1,1,2-trifluoroethane (HFC-143).

[0032] The inventors of this invention have noticed that trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)) and 1,1,2-trifluoroethylene (HFO-1123) obtained by existing methods contain hydrogen fluoride as a byproduct, and therefore it is necessary to separate it.

[0033] The inventors of this invention have discovered that the combination of these target substances and hydrogen fluoride forms azeotropic-like compositions, and that these compositions are useful when separated by methods such as distillation, extraction, or liquid-liquid separation, thereby completing this invention.

[0034] 1. Composition 1

[0035] Composition 1 is an azeotropic composition containing 1,2-difluoroethylene (HFO-1132) and hydrogen fluoride (HF).

[0036] HFO-1132 exists as structural isomers of HFO-1132(E) and HFO-1132(Z). In this specification, unless otherwise specified, HFO-1132 refers to HFO-1132(E) and / or HFO-1132(Z). In composition 1, HFO-1132 can be used alone, alone, or in mixtures of HFO-1132(E) and HFO-1132(Z). Furthermore, HFO-1132(E) or HFO-1132(Z) is preferred as HFO-1132.

[0037] From the viewpoint of effectively separating HFO-1132, composition 1 preferably contains 50% by mass or more but less than 100% by mass of HFO-1132 relative to 100% by mass of the total HFO-1132 and hydrogen fluoride, and more preferably contains 80% by mass or more but less than 100% by mass of HFO-1132.

[0038] Composition 1, at 40°C, is an azeotropic composition when it contains 99% by mass and less than 100% by mass of HFO-1132 relative to 100% by mass of the total of HFO-1132 and hydrogen fluoride; and is an azeotropic composition when it contains 97% by mole and less than 100% by mole of HFO-1132 relative to 100% by mole of the total of HFO-1132 and hydrogen fluoride.

[0039] In addition, when HFO-1132 is HFO-1132(E), composition 1 preferably has a boiling point of -40°C to 40°C at a pressure of 185 kPa to 2480 kPa; more preferably, it has a boiling point of -30°C to 30°C at a pressure of 279 kPa to 1850 kPa.

[0040] Similarly, when HFO-1132 is HFO-1132(Z), composition 1 preferably has a boiling point of -40°C to 40°C at a pressure of 51 kPa to 1880 kPa; more preferably, it has a boiling point of -30°C to 30°C at a pressure of 83 kPa to 691 kPa.

[0041] Composition 1 can become an azeotropic composition under the above-mentioned temperature and pressure range.

[0042] In addition, unless otherwise specified, pressure in this instruction manual refers to absolute pressure.

[0043] In addition to HFO-1132 and hydrogen fluoride, composition 1 may also contain additional compounds.

[0044] The additional compound is not particularly limited and can be widely selected within a range that does not prevent composition 1 from being an azeotropic composition. The additional compound can be one or more.

[0045] As additional compounds, additional compound 1 and additional compound 2 can be listed.

[0046] Examples of additional compound 1 include 1,1-difluoroethylene (HFO-1132a), 1,1,2-trifluoroethylene (HFO-1123), fluoromethane (HFC-41), 1,1,2,2-tetrafluoroethane (HFC-134) and 1,1,2-trifluoroethane (HFC-143).

[0047] Examples of additional compound 2 include E-1-chloro-2-fluoroethylene (HCFO-1131(E)), Z-1-chloro-2-fluoroethylene (HCFO-1131(Z)), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 2-chloro-1,1,1-trifluoroethane (HCFC-133a), 1-chloro-1,1,2-trifluoroethane (HCFC-133), 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123), and 1,2-difluoroethane (HFC-152).

[0048] From a more useful point of view, as the above-mentioned additional compound, in the case of forming a composition, additional compound 1 is preferred. That is, as the above-mentioned additional compound, it is preferred to be at least one selected from 1,1-difluoroethylene (HFO-1132a), 1,1,2-trifluoroethylene (HFO-1123), fluoromethane (HFC-41), 1,1,2,2-tetrafluoroethane (HFC-134), and 1,1,2-trifluoroethane (HFC-143).

[0049] When additional compound 1 is included as an additional compound, the total content of additional compound 1 is 100% by mass of the composition 1 as a whole, preferably greater than 0% by mass and less than 15% by mass, more preferably greater than 0% by mass and less than 10% by mass.

[0050] Furthermore, when additional compound 2 is included as an additional compound, the total content of additional compound 2 is 100% by mass of the entire composition 1, preferably greater than 0% by mass and less than 1% by mass, more preferably greater than 0% by mass and less than 0.5% by mass, and even more preferably greater than 0% by mass and less than 0.1% by mass.

[0051] Furthermore, when the additional compound includes both additional compound 1 and additional compound 2, it is preferable that additional compound 1 satisfies the total content of additional compound 1, and additional compound 2 satisfies the total content of additional compound 2.

[0052] Composition 1 can be an important composition when performing azeotropic distillation to separate HF from HFO-1132 in a mixture of HFO-1132 and HF.

[0053] For example, HF can be separated from HFO-1132 by azeotropic distillation of a quasi-azeotropic composition containing HFO-1132 and HF from a composition containing at least HFO-1132 and HF.

[0054] Azeotropic distillation is a method of concentrating or separating a target substance by operating a distillation column under conditions where an azeotropic or azeotropic-like composition is separated. There are cases where azeotropic distillation can distill only the target component, but there are also cases where azeotropic distillation only occurs when other components that form an azeotropic mixture with the target component are added from the outside. In this specification, both the former and the latter are referred to as azeotropic distillation.

[0055] 2. Composition 2

[0056] Composition 2 is an azeotropic composition containing 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride (HF).

[0057] From the viewpoint of effectively separating HFO-1123, composition 2 preferably contains 50% by mass or more but less than 100% by mass of HFO-1123 relative to 100% by mass of the total HFO-1123 and hydrogen fluoride, and more preferably contains 80% by mass or more but less than 100% by mass of HFO-1123.

[0058] Composition 2, at 40°C, is an azeotropic composition when it contains 99% by mass and less than 100% by mass of HFO-1123 relative to 100% by mass of the total of HFO-1123 and hydrogen fluoride; and is an azeotropic composition when it contains 97% by mole and less than 100% by mole of HFO-1123 relative to 100% by mole of the total of HFO-1123 and hydrogen fluoride.

[0059] Furthermore, composition 2 preferably has a boiling point of -40°C to 40°C at a pressure of 249 kPa to 3480 kPa; more preferably, it has a boiling point of -30°C to 30°C at a pressure of 372 kPa to 2375 kPa. Composition 2 becomes an azeotropic composition within the above-mentioned temperature and pressure ranges.

[0060] In addition to HFO-1123 and hydrogen fluoride, composition 2 may also contain additional compounds.

[0061] The additional compound is not particularly limited and can be widely selected within a range that does not prevent composition 2 from becoming an azeotropic composition. The additional compound can be one or more.

[0062] Additional compounds can be listed, such as E-1-chloro-2-fluoroethylene (HCFO-1131(E)), Z-1-chloro-2-fluoroethylene (HCFO-1131(Z)), 1,1,1-trifluoroethane (HFC-143a), 1,1-difluoroethylene (HFO-1132a), 1,1-difluoroethane (HFC-152a), fluoroethane (HFC-161), 1,1,2-trifluoroethane (HFC-143), 2-chloro-1,1,1-trifluoroethane (HCFC-133a), 1-chloro-1,1,2-trifluoroethane (HCFC-133), 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123), and 1,2-difluoroethane (HFC-152).

[0063] The total amount of the additional compounds can be appropriately selected within a range that does not prevent composition 2 from becoming an azeotropic composition.

[0064] When additional compounds are included, their total content is 100% by mass of the composition 2 as a whole, preferably greater than 0% by mass and less than 1% by mass, more preferably greater than 0% by mass and less than 0.5% by mass, and even more preferably greater than 0% by mass and less than 0.1% by mass.

[0065] Composition 2 can be an important composition for azeotropic distillation in a mixture of HFO-1123 and HF to separate HF from HFO-1123.

[0066] For example, HF can be separated from HFO-1123 by azeotropic distillation of a quasi-azeotropic composition containing HFO-1123 and HF from a composition containing at least HFO-1123 and HF.

[0067] 3. Separation Method

[0068] In this invention, a method for separating the components of the above composition is also disclosed.

[0069] The separation method of the present invention is a method for separating a composition comprising at least one selected from trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)) and 1,1,2-trifluoroethylene (HFO-1123), and hydrogen fluoride.

[0070] The separation method includes steps (a) and (b), and may also include step (c) if necessary:

[0071] (a) The process of feeding a composition comprising at least one selected from HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride into a first distillation column;

[0072] (b) The step of taking an azeotropic composition comprising at least one of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride as a first distillate, and taking a composition rich in i) at least one of HFO-1132(E), HFO-1132(Z) and HFO-1123 or ii) hydrogen fluoride at a higher concentration than the supplied composition as the bottom composition of a first distillation column;

[0073] (c) The process of feeding the first distillate to a second distillation column and distilling it at a different pressure than that of the first distillation column.

[0074] In the above separation method, the starting composition used in step (a) that comprises at least one selected from HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride may be a composition consisting only of at least one selected from HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride, or it may be a composition that contains other components in addition to at least one selected from HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride.

[0075] In step (b) above, in the composition after the first distillate is distilled from the supplied composition, the concentration of either i) or ii) is higher than the concentration in the supplied composition (because the total amount and composition of the composition will change). Moreover, the composition rich in either i) or ii) at a higher concentration than the supplied composition is taken out as the bottom composition of the first distillation column.

[0076] In the above separation method, step (c) is not a necessary step and can be performed arbitrarily. The above separation method can be a method consisting only of steps (a) to (b), a method consisting only of steps (a) to (c), or a method that includes other steps in addition to steps (a) to (c).

[0077] Furthermore, the operating conditions of the first and second distillation columns can be appropriately set. Moreover, from the viewpoint of distillation efficiency, it is preferable to set the operating conditions of the second distillation column differently from those of the first distillation column.

[0078] An example of the above separation method is shown in Figure 1 Another example is shown in Figure 2 .

[0079] exist Figure 1 In this context, C1 represents the first distillation column; it means that the composition is supplied from S11 to C1, the bottom composition of the first distillation column is taken out from S12, and the first distillate is obtained from S13.

[0080] exist Figure 2 In this diagram, C1 represents the first distillation column, and C2 represents the second distillation column; it indicates that the composition is supplied to C1 from S11, the bottom composition of the first distillation column is taken out from S12, the resulting first distillate is supplied to C2 from S13, the bottom composition of the second distillation column is taken out from S14, and the second distillate is obtained from S15. For example, the separability of each distillation column can be changed by altering the operating pressure of the second distillation column to be different from that of the first distillation column. HF, which cannot be separated in the first distillate, can be taken out as the bottom composition of the second distillation column, and HFO-1132 and / or HFO-1123 with higher purity can be obtained as the second distillate. The pressure range in each distillation column can be arbitrarily set within the pressure range where HFO-1132 and HFO-1123 each become azeotropic compositions. For HFO-1132(E), the pressure range is preferably 185 kPa to 2480 kPa; for HFO-1132(Z), it is preferably 51 kPa to 1880 kPa; and for HFO-1123, it is preferably 249 kPa to 3480 kPa.

[0081] The separation method described above includes the following steps: separating a composition containing at least one of HFO-1132(E), HFO-1132(Z), and HFO-1123, and hydrogen fluoride into at least one of HFO-1132(E), HFO-1132(Z), and HFO-1123, and hydrogen fluoride. This method utilizes the properties of becoming an azeotropic composition of HFO-1132(E), HFO-1132(Z), or HFO-1123 and hydrogen fluoride for distillation separation.

[0082] This separation method is preferably used in the cases of separating a composition containing HFO-1132(E) and hydrogen fluoride into HFO-1132(E) and hydrogen fluoride; separating a composition containing HFO-1132(Z) and hydrogen fluoride into HFO-1132(Z) and hydrogen fluoride; and separating a composition containing HFO-1123 and hydrogen fluoride into HFO-1123 and hydrogen fluoride.

[0083] The small amount of HF extracted along with the azeotropic composition can also be recovered by other conventional methods (such as water absorption) to minimize losses and reduce the burden on equipment. Alternatively, if water-free HF recovery methods such as absorption with H₂SO₄, extraction with the addition of a third component, or extractive distillation are used, the HF can be reused as a reaction feedstock along with the various compounds. When using extraction or extractive distillation, the recovery equipment using corrosive H₂SO₄ can be minimized, thus reducing equipment costs.

[0084] Thus, hydrogen fluoride can be effectively separated using the separation method of the present invention.

[0085] The above describes the implementation method, but it is understood that various changes in method or details can be made without departing from the spirit and scope of the patent claim.

[0086] Example

[0087] The following examples provide a more detailed description. However, the present invention is not limited to these examples.

[0088] Example 1

[0089] The vapor-liquid equilibrium data of mixtures of HFO-1132(E), HFO-1132(Z), or HFO-1123 with hydrogen fluoride (HF) at 40°C are shown in Tables 1 to 3. The values ​​for each compound in the liquid and gas phases are in molar ratio (the total number of moles of each compound and HF in both the liquid and gas phases is set to 1).

[0090] [Table 1]

[0091]

[0092] [Table 2]

[0093]

[0094] [Table 3]

[0095]

[0096] Table 1 shows that when HFO-1132(E) is 97 mol% or more (99 wt% or more) and less than 100 mol% in the combination of HFO-1132(E) and HF, it becomes an azeotropic composition.

[0097] Table 2 shows that when HFO-1132(Z) is 97 mol% or more (99 wt% or more) and less than 100 mol% in the combination of HFO-1132(Z) and HF, it becomes an azeotropic composition.

[0098] Table 3 shows that in the combination of HFO-1123 and HF, when HFO-1123 is 97 mol% or more (99 wt% or more) and less than 100 mol%, it becomes an azeotropic composition.

[0099] This indicates that, in the above gas-liquid equilibrium data at 40°C, the cases where HFO-1132(E), HFO-1132(Z), and HFO-1123 each constitute 97 mol% or more but less than 100 mol% in the composition with HF correspond to the case where the difference between the bubble point vapor pressure and the dew point vapor pressure of the composition at 40°C is less than 3%, and thus constitute an azeotropic composition.

[0100] Based on the above analysis, HFO-1132(E), HFO-1132(Z), and HFO-1123 form azeotropic compositions with HF. These compositions are important for the separation of HF in distillation columns.

[0101] An azeotropic composition comprising HFO-1132(E) and / or HFO-1132(Z), hydrogen fluoride (HF), and an additional compound selected from HFO-1132a, HFO-1123, HFC-41, HFC-134, and HFC-143 is a preferred composition useful for separating HFO-1132(E) and / or HFO-1132(Z), HF, and the additional compound.

[0102] In addition, in the compositions containing HFO-1132(E), HF and HFO-1132a; the compositions containing HFO-1132(E), HF and HFO-1123; the compositions containing HFO-1132(E), HF and HFC-41; the compositions containing HFO-1132(E), HF and HFC-134; and the compositions containing HFO-1132(E), HF and HFC-143, the difference between the bubble point vapor pressure and the dew point vapor pressure at a specific temperature is less than 3%.

[0103] Example 2: Method for separating HFO-1132(E) and hydrogen fluoride

[0104] Figure 1This illustrates an example of a separation method utilizing azeotropic compositions. Additionally, Figure 1 The flow rates of HFO-1132(E) and hydrogen fluoride in S11, S12, and S13 are shown in Table 4. Furthermore, the operating pressure of distillation column C1 is 1.01 MPa, the top temperature is 7.9 °C, and the bottom temperature is 98.1 °C.

[0105] In step S11, the composition of HFO-1132(E) and hydrogen fluoride is fed into distillation column C1. In step S13, the azeotropic composition of HFO-1132(E) and hydrogen fluoride elutes, yielding HFO-1132(E) with a reduced concentration of hydrogen fluoride. Trace amounts of residual hydrogen fluoride in step S13 can be removed by washing, adsorption, or absorption. Step S12 essentially yields only hydrogen fluoride, which is then reused in the reaction process.

[0106] In addition, the systems of HFO-1132(Z) and HF, and HFO-1123 and HF, can also be separated by azeotropic distillation and reused in the reaction process.

[0107] [Table 4]

[0108]

Claims

1. An azeotropic composition, characterized in that: Composed solely of trans-1,2-difluoroethylene (HFO-1132(E)), hydrogen fluoride, and additional compounds. The additional compound is selected from at least one of 1,1-difluoroethylene (HFO-1132a), 1,1,2-trifluoroethylene (HFO-1123), fluoromethane (HFC-41), 1,1,2,2-tetrafluoroethane (HFC-134), and 1,1,2-trifluoroethane (HFC-143). Relative to 100% by mass of the azeotropic composition as a whole, the additional compounds contain more than 0% by mass and less than 15% by mass. Of 100% by mass of HFO-1132(E) and hydrogen fluoride, the content is more than 99% by mass and less than 100% by mass of the aforementioned HFO-1132(E). It becomes an azeotropic composition at -40℃ to 40℃ and 185kPa to 2480kPa.

2. An azeotropic composition, characterized in that: It consists only of cis-1,2-difluoroethylene (HFO-1132(Z)), hydrogen fluoride, and additional compounds selected from at least one of 1,1-difluoroethylene (HFO-1132a), 1,1,2-trifluoroethylene (HFO-1123), fluoromethane (HFC-41), 1,1,2,2-tetrafluoroethane (HFC-134), and 1,1,2-trifluoroethane (HFC-143). Relative to 100% by mass of the azeotropic composition as a whole, the additional compounds contain more than 0% by mass and less than 15% by mass. Of 100% by mass of HFO-1132(Z) and hydrogen fluoride, the content is more than 99% by mass and less than 100% by mass of the aforementioned HFO-1132(Z). It becomes an azeotropic composition at -40℃ to 40℃ and 51kPa to 1880kPa.

3. An azeotropic composition, characterized in that: Composed solely of 1,1,2-trifluoroethylene (HFO-1123), hydrogen fluoride, and additional compounds. Relative to 100% by mass of the azeotropic composition as a whole, the additional compounds contain more than 0% by mass and less than 1% by mass. The total mass of HFO-1123 and hydrogen fluoride is 100% by mass, comprising more than 99% by mass and less than 100% by mass of the HFO-1123.

4. A method for separating a composition, characterized in that: This composition consists only of trans-1,2-difluoroethylene (HFO-1132(E)) and hydrogen fluoride. The separation method includes steps (a) and (b), and may also include step (c) if necessary. (a) The process of supplying a composition consisting solely of HFO-1132(E) hydrogen fluoride to the first distillation column; (b) The process of extracting an azeotropic composition consisting only of HFO-1132(E) and hydrogen fluoride as the first distillate, and extracting a composition rich in either i) or ii) at a higher concentration than the supplied composition as the bottom composition of the first distillation column. i)HFO-1132(E), ii) Hydrogen fluoride; (c) The process of feeding the first distillate to a second distillation column, where distillation is carried out at a different pressure than in the first distillation column. In steps (b) and (c), the pressure during distillation is 185 kPa to 2480 kPa.

5. A method for separating a composition, characterized in that: This composition consists only of cis-1,2-difluoroethylene (HFO-1132(Z)) and hydrogen fluoride. The separation method includes steps (a) and (b), and may also include step (c) if necessary. (a) The process of supplying a composition consisting solely of HFO-1132(Z) hydrogen fluoride to the first distillation column; (b) The process of extracting an azeotropic composition consisting only of HFO-1132(Z) and hydrogen fluoride as the first distillate, and extracting a composition rich in either i) or ii) at a higher concentration than the supplied composition as the bottom composition of the first distillation column. i)HFO-1132(Z), ii) Hydrogen fluoride; (c) The process of feeding the first distillate to a second distillation column, where distillation is carried out at a different pressure than in the first distillation column. In steps (b) and (c), the pressure during distillation is 51 kPa to 1880 kPa.

6. A method for separating a composition, characterized in that: This composition consists only of 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride. The separation method includes steps (a) and (b), and may also include step (c) if necessary. (a) The process of supplying a composition consisting solely of HFO-1123 hydrogen fluoride to the first distillation column; (b) The process of extracting an azeotropic composition consisting only of HFO-1123 and hydrogen fluoride as the first distillate, and extracting a composition rich in either i) or ii) at a higher concentration than the supplied composition as the bottom composition of the first distillation column. i)HFO-1123, ii) Hydrogen fluoride; (c) The process of feeding the first distillate to a second distillation column, where distillation is carried out at a different pressure than in the first distillation column. In steps (b) and (c), the pressure during distillation is 249 kPa to 3480 kPa.

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