Azeotropic composition containing 1,2-difluoroethylene or 1,1,2-trifluoroethylene and hydrogen fluoride
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- DAIKIN INDUSTRIES LTD
- Filing Date
- 2024-02-07
- Publication Date
- 2026-06-11
Smart Images
Figure 00000009_0000 
Figure 00000009_0001
Abstract
Description
[Technical field] 【0001】 The present disclosure relates to an azeotrope-like composition containing 1,2-difluoroethylene or 1,1,2-trifluoroethylene and hydrogen fluoride, and a method for separating hydrogen fluoride from the composition. [Background technology] 【0002】 A heat cycle working fluid containing 1,2-difluoroethylene (HFO-1132) is known. This working fluid is described as having a small impact on the ozone layer and a small impact on global warming because it contains HFO-1132, which has a carbon-carbon double bond that is easily decomposed by OH radicals in the atmosphere (Patent Document 1). Furthermore, a method for producing 1,1,2-trifluoroethylene (HFO-1123) is known in which the product is produced by dehydrofluorinating 1,1,1,2-tetrafluoroethane (Patent Document 2). [Prior art documents] [Patent documents] 【0003】 [Patent Document 1] International Publication No. 2012 / 157765 [Patent Document 2] International Publication No. 2009 / 010472 Summary of the Invention [Problem to be solved by the invention] 【0004】 An object of the present disclosure is to provide a new azeotrope-like composition and a separation method using the same. [Means for solving the problem] 【0005】 Item 1. An azeotrope-like composition comprising 1,2-difluoroethylene (HFO-1132) and hydrogen fluoride. Item 2. The azeotrope-like composition according to Item 1, wherein the HFO-1132 is trans-1,2-difluoroethylene (HFO-1132(E)). Item 3. The azeotrope-like composition according to Item 1, wherein the HFO-1132 is cis-1,2-difluoroethylene (HFO-1132(Z)). Item 4. The azeotrope-like composition according to Item 2, having a boiling point of -40°C to 40°C at a pressure of 185 kPa to 2480 kPa. Item 5. The azeotrope-like composition according to Item 3, having a boiling point of -40°C to 40°C at a pressure of 51 kPa to 1880 kPa. Item 6. 1,2-Difluoroethylene (HFO-1132) and hydrogen fluoride, 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 at least one additional compound selected from the group consisting of fluoroethane (HFC-143); Item 6. The azeotrope-like composition according to any one of items 1 to 5, comprising: Item 7. An azeotrope-like composition comprising 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride. Item 8. The azeotrope-like composition according to Item 7, having a boiling point of -40°C to 40°C at a pressure of 249 kPa to 3480 kPa. Item 9. The method includes steps (a) and (b) and, if necessary, further includes step (c); A method for separating a composition containing 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: (a) supplying a composition comprising at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123, and hydrogen fluoride, to a first distillation column; (b) obtaining an azeotrope-like composition comprising at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride as a first distillate, and withdrawing a composition which is enriched in either i) at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 or ii) hydrogen fluoride as compared to the composition fed as a bottom composition from the first distillation column; (c) feeding the first distillate to a second distillation column and distilling in the second distillation column at a pressure different from that of the first distillation column. Effect of the Invention 【0006】 The present disclosure provides new azeotrope-like compositions and separation methods using same. [Brief description of the drawings] 【0007】 [Figure 1] FIG. 1 shows an example of a separation method using an azeotrope-like composition. [Diagram 2] FIG. 1 is a diagram showing another example of a separation method using an azeotrope-like composition. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 【0008】 As used herein, the term "azeotrope-like composition" refers to a composition that can be treated substantially similarly to an azeotrope composition. Specifically, as used herein, the term "azeotrope-like composition" refers to a constant-boiling or substantially constant-boiling mixture of two or more substances that behave substantially as a single substance. One of the characteristics of an azeotrope-like composition is that the composition of the vapor generated by evaporation or distillation of a liquid does not change substantially from the composition of the liquid. That is, as used herein, when a mixture boils, distills, or refluxes without a substantial change in composition, the mixture is called an azeotrope-like composition. Specifically, in the present disclosure, when the difference between the bubble point vapor pressure of a composition at a certain temperature and the dew point vapor pressure of the composition is 3% or less (based on the bubble point pressure), the composition is defined as an azeotrope-like composition. 【0009】 Here, as a method for producing 1,2-difluoroethylene (HFO-1132), for example, there is a method for producing it by dehydrofluorination of 1,1,2-trifluoroethane (HFC-143). The present inventors have noted that trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)), and 1,1,2-trifluoroethylene (HFO-1123) obtained by conventional methods contain hydrogen fluoride as a by-product, and therefore, separation of this by-product is necessary. The present inventors have discovered that combinations of these target products and hydrogen fluoride form azeotrope-like compositions, and further discovered that these compositions are useful when separated by methods such as distillation, extraction or liquid-liquid separation, and have thus completed the present invention. 【0010】 1. Composition 1 Composition 1 is an azeotrope-like composition comprising 1,2-difluoroethylene (HFO-1132) and hydrogen fluoride (HF). HFO-1132 has structural isomers, HFO-1132(E) and HFO-1132(Z). In this specification, unless otherwise specified, HFO-1132 means one consisting of HFO-1132(E) and / or HFO-1132(Z). In the composition 1, HFO-1132 may be HFO-1132(E) alone, HFO-1132(Z) alone, or a mixture of HFO-1132(E) and HFO-1132(Z). In addition, HFO-1132 is preferably HFO-1132(E) or HFO-1132(Z). In order to perform efficient separation, composition 1 preferably contains 50 mass% or more and less than 100 mass% of HFO-1132, and more preferably 80 mass% or more and less than 100 mass%, relative to 100 mass% in total of HFO-1132 and hydrogen fluoride. 【0011】 Composition 1 becomes an azeotrope-like composition at 40°C when it contains 99% by mass or more but less than 100% by mass of HFO-1132 relative to 100% by mass of the total of HFO-1132 and hydrogen fluoride; An azeotrope-like composition is formed when the content of HFO-1132 is 97 mol % or more and less than 100 mol % relative to 100 mol % of the total hydrogen fluoride. 【0012】 In addition, when HFO-1132 is HFO-1132(E), composition 1 is heated at a pressure of 185 kPa to 2480 kPa. In a, it is preferable that the boiling point is −40° C. to 40° C.; it is more preferable that the boiling point is −30° C. to 30° C. at a pressure of 279 kPa to 1850 kPa. Similarly, when HFO-1132 is HFO-1132(Z), composition 1 is In a, it is preferable that the boiling point is −40° C. to 40° C.; it is more preferable that the boiling point is −30° C. to 30° C. at a pressure of 83 kPa to 691 kPa. Composition 1 may be an azeotrope-like composition within the above temperature and pressure ranges. In this specification, unless otherwise specified, pressure refers to absolute pressure. 【0013】 Composition 1 may further include additional compounds in addition to HFO-1132 and hydrogen fluoride. The additional compound is not particularly limited and can be selected from a wide range as long as it does not inhibit the composition 1 from becoming an azeotrope-like composition. The additional compound may be one type or multiple types. The additional compounds include Additional Compound 1 and Additional Compound 2. Additional Compound 1 includes 1,1-difluoroethylene (HFO-1132a), 1,1,2-trifluoroethylene (HFO-1132a), These include fluoroethylene (HFO-1123), fluoromethane (HFC-41), 1,1,2,2-tetrafluoroethane (HFC-134), and 1,1,2-trifluoroethane (HFC-143). Additional compounds 2 include, for example, 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), 1,2-difluoroethane (HFC-152), etc. 【0014】 As the additional compound, additional compound 1 is preferred because it is more useful when made into a composition. That is, as the additional compound, 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) are preferred. When additional compound 1 is included as an additional compound, the total content of additional compound 1 is preferably more than 0 mass% and not more than 15 mass%, and more preferably more than 0 mass% and not more than 10 mass%, with the entire composition 1 being 100 mass%. 【0015】 Furthermore, when additional compound 2 is included as an additional compound, the total content of additional compound 2 is preferably more than 0 mass% and not more than 1 mass%, more preferably more than 0 mass% and not more than 0.5 mass%, and even more preferably more than 0 mass% and not more than 0.1 mass%, with the entire composition 1 being 100 mass%. Furthermore, when the additional compounds include both additional compound 1 and additional compound 2, it is preferable that additional compound 1 satisfies the total content of the additional compound 1, and additional compound 2 satisfies the total content of the additional compound 2. 【0016】 Composition 1 may be an important composition in the azeotropic distillation of a mixture of HFO-1132 and HF to separate HF from HFO-1132. For example, HF can be separated from HFO-1132 by removing an azeotrope-like composition comprising HFO-1132 and HF from a composition comprising at least HFO-1132 and HF by azeotropic distillation. 【0017】 Azeotropic distillation is a method of concentrating or separating a target substance by operating a distillation column under conditions in which an azeotropic or azeotrope-like composition is separated. In some cases, only the components to be separated can be distilled by azeotropic distillation, but in other cases, azeotropic distillation can only occur when another component that forms an azeotropic mixture with one or more of the components to be separated is added from the outside. In this specification, both the former and the latter are referred to as azeotropic distillation. 【0018】 2. Composition 2 Composition 2 is an azeotrope-like composition comprising 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride (HF). In order to efficiently separate the components, composition 2 preferably contains 50% by mass or more and less than 100% by mass of HFO-1123, and more preferably 80% by mass or more and less than 100% by mass, relative to 100% by mass of the combined total of HFO-1123 and hydrogen fluoride. 【0019】 Composition 2 becomes an azeotrope-like composition at 40°C when it contains 99% by mass or more and less than 100% by mass of HFO-1123 relative to 100% by mass of the total of HFO-1123 and hydrogen fluoride; and it becomes an azeotrope-like composition when it contains 97% by mol or more and less than 100% by mol of HFO-1123 relative to 100 mol% of the total of HFO-1123 and hydrogen fluoride. 【0020】 Composition 2 preferably has a boiling point of -40°C to 40°C at a pressure of 249 kPa to 3480 kPa, and more preferably has a boiling point of -30°C to 30°C at a pressure of 372 kPa to 2375 kPa. Composition 2 can be an azeotrope-like composition within the above temperature and pressure ranges. 【0021】 Composition 2 may further include additional compounds in addition to HFO-1123 and hydrogen fluoride. The additional compound is not particularly limited and can be selected from a wide range as long as it does not inhibit the composition 2 from becoming an azeotrope-like composition. The additional compound may be one type or multiple types. 【0022】 Additional compounds include, for example, 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-152a), fluoroethane (HFC-152b), fluoroethane (HFC-152c), fluoroethane (HFC-152d ...b), fluoroethane (HFC-152c), fluoroethane (HFC-152d), fluoroethane (HFC-152c), fluoroethane (HFC-152b), fluoroethane (HFC-152c), fluoroethane (HFC Oroethane (HFC-161), 1,1,2-trifluoroethane (HFC-143), 2-chloro-1,1,1-trifluoroethane Fluoroethane (HCFC-133a), 1-chloro-1,1,2-trifluoroethane (HCFC-133), 2,2-dichloro-1,1,1-trifluoroethane (HCFC-123), 1,2-difluoroethane (HFC-152), and the like. 【0023】 The total content of the additional compounds can be appropriately selected within a range that does not inhibit composition 2 from becoming an azeotrope-like composition. When additional compounds are included, the total content thereof is preferably greater than 0% by mass and not greater than 1% by mass, more preferably greater than 0% by mass and not greater than 0.5% by mass, and even more preferably greater than 0% by mass and not greater than 0.1% by mass, with the entire composition 2 being 100% by mass. 【0024】 Composition 2 may be an important composition in mixtures of HFO-1123 and HF when performing azeotropic distillation to separate HF from HFO-1123. For example, HF can be separated from HFO-1123 by removing an azeotrope-like composition comprising HFO-1123 and HF from a composition comprising at least HFO-1123 and HF by azeotropic distillation. 【0025】 3.Separation method The present disclosure also discloses a method for separating each component using the above composition. The separation method of the present disclosure includes steps (a) and (b), and optionally further includes step (c). A method for separating a composition containing 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: (a) supplying a composition comprising at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123, and hydrogen fluoride, to a first distillation column; (b) obtaining an azeotrope-like composition comprising at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride as a first distillate, and withdrawing a composition which is enriched in either i) at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 or ii) hydrogen fluoride as compared to the composition fed as a bottom composition from the first distillation column; (c) feeding the first distillate to a second distillation column and distilling in the second distillation column at a pressure different from that of the first distillation column. 【0026】 In the above separation method, the starting composition used in step (a), which contains at least one type selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride, may be a composition consisting only of at least one type selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride, or it may be a composition which further contains other components in addition to at least one type selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride. 【0027】 In the above step (b), the concentration of either i) or ii) in the composition after the first distillate is distilled from the supplied composition becomes higher than the concentration in the supplied composition (because the total amount and composition of the composition change). Then, this composition having a higher concentration of either i) or ii) than the supplied composition is extracted as the bottom composition of the first distillation column. 【0028】 In the above separation method, step (c) is not an essential step and may be optionally performed. The above separation method may be a method consisting of only the above steps (a) to (b), a method consisting of only the above steps (a) to (c), or a method including other steps in addition to the above steps (a) to (c). The operating conditions of the first and second distillation columns can be appropriately set. From the viewpoint of distillation efficiency, it is preferable that the operating conditions of the second distillation column are different from those of the first distillation column. 【0029】 An example of the above separation method is shown in FIG. 1, and another example is shown in FIG. In FIG. 1, C1 denotes a first distillation column; a composition is supplied to C1 from S11, a bottom composition of the first distillation column is withdrawn from S12, and a first distillate is obtained from S13. In FIG. 2, C1 indicates the first distillation column, C2 indicates the second distillation column; the composition is supplied from S11 to C1. The bottom composition of the first distillation column is extracted from S12, the first distillate obtained from S13 is supplied to C2, the bottom composition of the second distillation column is extracted from S14, and the second distillate is obtained from S15. For example, by changing the operating pressure of the second distillation column from that of the first distillation column, the separation properties in each distillation column can be changed, and HF that could not be separated in the first distillate can be extracted 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 is arbitrarily set within a pressure range in which HFO-1132 and HFO-1123 each become an azeotrope-like composition. The pressure range is 185 kPa to 2480 kPa in the case of HFO-1132(E). kPa is 51kPa to 1880kPa for HFO-1132(Z), and 249kPa for HFO-1123. Pa to 3480 kPa is preferred. 【0030】 The above separation method comprises separating at least one compound selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123. This separation method comprises a step of separating a composition containing at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride into at least one selected from the group consisting of HFO-1132(E), HFO-1132(Z) and HFO-1123 and hydrogen fluoride. This method utilizes the property of HFO-1132(E), HFO-1132(Z) or HFO-1123 forming an azeotrope-like composition with hydrogen fluoride to effect distillation separation. This separation method is preferably used when separating a composition containing HFO-1132(E) and hydrogen fluoride into HFO-1132(E) and hydrogen fluoride; when separating a composition containing HFO-1132(Z) and hydrogen fluoride into HFO-1132(Z) and hydrogen fluoride; and when separating a composition containing HFO-1123 and hydrogen fluoride into HFO-1123 and hydrogen fluoride. 【0031】 The small amount of HF extracted as an azeotrope-like composition can be recovered by using other common methods (absorption with water) in combination to minimize losses and reduce the burden on the equipment. In addition, HF recovery without using water, such as absorption with H2SO4, extraction with the addition of a third component, and extractive distillation, is also possible. By using the recovery method, both the compounds and HF can be reused as raw materials for the reaction. By using extraction or extractive distillation, the recovery equipment using corrosive H2SO4 can be minimized. Equipment costs can be reduced. In this way, according to the separation method of the present disclosure, hydrogen fluoride can be separated efficiently. 【0032】 Although the embodiments have been described above, it will be understood that various changes in form and details are possible without departing from the spirit and scope of the claims. EXAMPLES 【0033】 The present disclosure will be described in more detail below by way of examples, although the present disclosure is not limited to these examples. 【0034】 Example 1 The vapor-liquid equilibrium data at 40° C. for mixtures of HFO-1132(E), HFO-1132(Z) or HFO-1123 with hydrogen fluoride (HF) are shown in Tables 1 to 3. The units of values in the tables for each compound in the liquid phase and gas phase are molar ratios (the total number of moles of each compound and HF in the liquid phase and gas phase, respectively, is 1). 【0035】 [Table 1] 【0036】 [Table 2] 【0037】 [Table 3] 【0038】 Table 1 shows that in a composition of HFO-1132(E) and HF, an azeotrope-like composition is formed when the HFO-1132(E) content is 97 mol % or more (99 mass % or more) but less than 100 mol %. Table 2 shows that in a composition of HFO-1132(Z) and HF, an azeotrope-like composition is formed when the HFO-1132(Z) content is 97 mol % or more (99 mass % or more) but less than 100 mol %. Table 3 shows that in a composition of HFO-1123 and HF, an azeotrope-like composition is formed when the HFO-1123 content is 97 mol % or more (99 mass % or more) but less than 100 mol %. Thus, in the above-mentioned vapor-liquid equilibrium data at 40°C, when HFO-1132(E), HFO-1132(Z), and HFO-1123 are each 97 mol % or more and less than 100 mol % in the composition with HF, this corresponds to a case where the difference between the bubble point vapor pressure and the dew point vapor pressure of the composition at 40°C is 3% or less, indicating that the composition is an azeotrope-like composition. From the above, it was found that HFO-1132(E), HFO-1132(Z) and HFO-1123 each form an azeotrope-like composition with HF. These compositions are important for separating HF from the HF in a distillation column. 【0039】 HFO-1132(E) and / or HFO-1132(Z), hydrogen fluoride (HF), and at least one additional compound selected from the group consisting of HFO-1132a, HFO-1123, HFC-41, HFC-134, and HFC-143. Azeotrope-like compositions comprising HFO-1132(E) and / or HFO-1132(Z), HF, and the additional compound are preferred compositions useful in separating HFO-1132(E) and / or HFO-1132(Z), HF, and the additional compound. Also, compositions containing HFO-1132(E), HF and HFO-1132a; A composition comprising HFO-1132(E), HF and HFC-41; A composition comprising HFO-1132(E), HF and HFC-134 In a composition 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 was 3% or less. 【0040】 Example 2: Method for separating HFO-1132(E) and hydrogen fluoride FIG. 1 shows an example of a separation method using an azeotrope-like composition. In addition, in S11, S12, and S13 in FIG. The flow rates of HFO-1132(E) and hydrogen fluoride are shown in Table 4. The operating pressure of distillation column C1 is 1.01 MPa, the column top temperature is 7.9°C, and the column bottom temperature is 98.1°C. From S11, a composition of HFO-1132(E) and hydrogen fluoride is supplied to the distillation column C1. From S13, an azeotrope-like composition of HFO-1132(E) and hydrogen fluoride flows out, and HFO-1132(E) with a reduced concentration of hydrogen fluoride flows out. In S13, the trace amount of hydrogen fluoride remaining is removed by washing with water, adsorption, absorption, etc. From S12, essentially only hydrogen fluoride is obtained, which can be recycled to the reaction process. will be installed. In addition, the HFO-1132(Z) and HF systems and the HFO-1123 and HF systems were also subjected to azeotropic distillation in the same manner. By carrying out the above steps, the two can be separated and recycled to the reaction process. 【0041】 [Table 4]
Claims
[Claim 1] An azeotropic composition consisting only of 1,1,2-trifluoroethylene (HFO-1123) and hydrogen fluoride, The azeotropic composition comprising 99% by mass or more and less than 100% by mass of HFO-1123. [Claim 2] A method for separating hydrogen fluoride from a composition consisting only of trans-1,2-difluoroethylene (HFO-1132(E)), cis-1,2-difluoroethylene (HFO-1132(Z)), or 1,1,2-trifluoroethylene (HFO-1123), and hydrogen fluoride, comprising steps (a) and (b): (a) A step of supplying a composition consisting only of HFO-1132(E), HFO-1132(Z), or HFO-1123, and hydrogen fluoride to the first distillation column; (b) A step of taking an azeotropic composition consisting only of HFO-1132(E), HFO-1132(Z), or HFO-1123, and hydrogen fluoride as the first distillate, and withdrawing a composition in which i) HFO-1132(E), HFO-1132(Z), or HFO-1123, or ii) hydrogen fluoride is more concentrated than the supplied composition, as the bottom composition of the first distillation column.