Separation and purification method and system for deuterated formic acid electrolyte

Abstract

The invention provides a separation and purification method and system for a deuterated formic acid electrolyte. The method comprises the following steps: performing cation exchange on a deuterated formic acid electrolyte to obtain a deuterated formic acid heavy water solution containing deuterated sulfuric acid; carrying out atmospheric distillation on the deuterated formic acid heavy water solution containing deuterated sulfuric acid to respectively obtain a dilute deuterated formic acid heavy water solution and deuterated sulfuric acid; carrying out pressurized rectification on the dilute deuterated formic acid heavy water solution to respectively obtain heavy water and primary purified deuterated formic acid; and carrying out reduced pressure rectification on the primary purified deuterated formic acid to respectively obtain secondary purified deuterated formic acid and a deuterated formic acid-heavy water mixed solution. According to the separation and purification method of the deuterated formic acid electrolyte, deuterated formic acid can be purified from the deuterated formic acid electrolyte, heavy water, deuterated sulfuric acid and deuterated sulfate in the deuterated formic acid electrolyte can be recycled, and the economical efficiency of the method is improved.

Description

Technical Field

[0001] This invention belongs to the field of refining and purification technology of deuterated chemicals, specifically relating to a method for separating and purifying deuterated formic acid electrolyte. Furthermore, this invention also relates to a system for separating and purifying deuterated formic acid electrolyte. Background Technology

[0002] Deuterated compounds are new compounds obtained by replacing one or more hydrogen atoms in the carbon-hydrogen bonds (CH bonds) of a compound molecule with deuterium atoms. They possess excellent stability and superb solubility, and have important applications in fields such as nuclear magnetic resonance (NMR), OLED materials, disease diagnosis, and mass spectrometry standards. Among them, deuterated formic acid is one of the most important organic chemical raw materials for deuterated products, and a variety of high-value deuterated chemicals can be synthesized based on deuterated formic acid.

[0003] However, because formic acid is miscible with water in any proportion to form an azeotropic mixture (containing 22% water), high-concentration formic acid solutions cannot be obtained using ordinary distillation methods. Currently, the main industrial methods for obtaining high-concentration formic acid are extractive distillation and pressure-swing azeotropic distillation. Extractive distillation often uses organic solvents with high boiling points, which not only results in high costs for solvent recovery and reuse but also carries the risk of deuteration substitution of the deuterated formic acid by introducing other reagents, thus reducing product purity.

[0004] The principle of pressure swing azeotropic distillation is based on the different azeotropic compositions of formic acid and water under different pressures. Water-azeotropic and formic acid-azeotropic distillation are performed separately to ultimately separate formic acid from water, yielding a high-concentration formic acid. However, due to the different physical properties of formic acid and deuterated formic acid, excessively high pressure or temperature can lead to formic acid decomposition. Furthermore, during purification, it is crucial to prevent the replacement of deuterium atoms in deuterated formic acid with hydrogen atoms. For example, if water vapor in the air condenses into droplets and enters the formic acid, the hydrogen atoms in the water droplets will replace the deuterium atoms in the deuterated formic acid. Simultaneously, during vacuum distillation, the negative pressure and the condensation temperature at the top of the column must be controlled to prevent them from becoming too low; otherwise, deuterated formic acid may solidify in the pipeline, affecting product purity.

[0005] However, the pressure swing azeotropic distillation process for formic acid is not well-suited for the electrolytic production of deuterated formic acid. This is because the electrolyte for deuterated formic acid contains not only a large amount of heavy water, but also deuterated sulfuric acid and deuterated sulfate catalysts. All three substances need to be recovered and reused to improve the process's economics. Therefore, conventional formic acid purification processes are not suitable for deuterated formic acid.

[0006] Therefore, developing a method and system that can both purify deuterated formic acid from deuterated formic acid electrolyte and recover and utilize heavy water, deuterated sulfuric acid, and deuterated sulfate catalysts in the deuterated formic acid electrolyte has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to solve the problems existing in the prior art and provide a method for separating and purifying deuterated formic acid electrolyte. This method is based on cation exchange coupled pressure swing azeotropic distillation, which achieves the purification of a 10% (w / w) deuterated formic acid-heavy aqueous solution to high-purity deuterated formic acid with a (w / w) concentration of not less than 98%, and a deuterium purity >99%. Simultaneously, it allows for the recovery and reuse of heavy water, deuterated sulfuric acid, and sulfate catalyst. This invention is particularly suitable for the concentration and purification of deuterated formic acid in low-concentration deuterated formic acid electrolytes and the recovery and reuse of solvent catalysts.

[0008] This invention is achieved through the following technical solution:

[0009] One of the objectives of this invention is to provide a method for separating and purifying deuterated formic acid electrolyte, comprising the following steps:

[0010] (1) The deuterated formic acid electrolyte was subjected to cation exchange to obtain a deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid;

[0011] (2) The deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid is subjected to atmospheric pressure distillation to obtain dilute deuterated formic acid heavy aqueous solution and deuterated sulfuric acid, respectively.

[0012] (3) The dilute deuterated formic acid heavy aqueous solution was subjected to pressure distillation to obtain heavy water and first-stage purified deuterated formic acid, respectively.

[0013] (4) The first-stage purified deuterated formic acid is subjected to vacuum distillation to obtain second-stage purified deuterated formic acid and a deuterated formic acid-heavy water mixture, respectively.

[0014] Preferably, the deuterated formic acid-heavy water mixture is refluxed into a dilute deuterated formic acid heavy water solution.

[0015] In a preferred embodiment of the present invention, in step (1),

[0016] Cation exchange is performed using cation exchange resin;

[0017] Preferably, the cation exchange resin is a strong acid type cation exchange resin;

[0018] More preferably, the active groups of the cation exchange resin are selected from sulfonic acid groups and / or phosphate groups;

[0019] Most preferably, the cation exchange resin is selected from any one of polystyrene-type, polyvinyl chloride-type, polysulfone-type, polyphenylene ether-type, and polyetherketone-type cation exchange resins.

[0020] In a preferred embodiment of the present invention, in step (2),

[0021] The operating temperature for atmospheric distillation is 101–111°C, preferably 101–107°C, and more preferably 101.3–102.3°C;

[0022] Preferably, the deuterated sulfuric acid is refluxed to the cation exchange resin for ion exchange to remove the deuterated sulfate.

[0023] In a preferred embodiment of the present invention, in step (3),

[0024] The operating pressure for pressurized distillation is 0.1–0.3 MPa(G), preferably 0.15–0.2 MPa(G); and / or

[0025] The theoretical plate number of pressurized distillation is 15–40, preferably 15–30; and / or

[0026] The reflux ratio for pressurized distillation is 1-10, preferably 1-5; and / or

[0027] The operating temperature at the top of the pressurized distillation column is 130.0–150.0℃, preferably 132.0–137.0℃; and / or

[0028] The operating temperature of the reboiler in the pressurized distillation column is 135.0–155.0℃, preferably 138.0–143.0℃.

[0029] In a preferred embodiment of the present invention, in step (4),

[0030] The operating pressure for vacuum distillation is 1–20 kPa(A), preferably 1–10 kPa(A); and / or

[0031] The theoretical plate number of vacuum distillation is 20–40, preferably 20–30; and / or

[0032] The reflux ratio for vacuum distillation is 2–10, preferably 2–5; and / or

[0033] The operating temperature at the top of the reduced-pressure distillation column is 55.0–65.0℃, preferably 56.0–59.0℃; and / or

[0034] The operating temperature of the reboiler in vacuum distillation is 58–68°C, preferably 60.0–63.0°C.

[0035] In a preferred embodiment of the present invention, the following steps are also included:

[0036] (5) Dehydrate the secondary purified deuterated formic acid obtained in step (4), preferably by adding a desiccant;

[0037] (6) The dehydrated secondary purified deuterated formic acid is subjected to atmospheric pressure distillation to obtain deuterated formic acid with a mass concentration of not less than 98%.

[0038] In a preferred embodiment of the present invention, in step (5),

[0039] The desiccant is selected from at least one of anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and molecular sieves; and / or

[0040] The mass ratio of the desiccant to the deuterated formic acid is (15-50):100, preferably (20-30):100.

[0041] In a preferred embodiment of the present invention, in step (6)

[0042] The operating temperature for atmospheric distillation is 100–105°C, preferably 100–102°C, and more preferably 100.8–101.3°C.

[0043] The second objective of this invention is to provide a separation and purification system for deuterated formic acid electrolyte, comprising an ion exchange device, an atmospheric distillation apparatus, a pressurized distillation column, and a vacuum distillation column connected in sequence by pipelines, wherein the ion exchange device is filled with cation exchange resin.

[0044] In a preferred embodiment of the present invention

[0045] The feed inlet of the ion exchange equipment is connected to the deuterated formic acid electrolyte feed tank, and the outlet of the ion-exchanged material on its side wall is connected to the inlet of the atmospheric distillation unit; a deuterated sulfate recovery tank is connected to the top of the ion exchange equipment, and a deuterated sulfuric acid recovery tank is connected to its bottom; and / or,

[0046] The atmospheric distillation apparatus has a deuterated sulfuric acid outlet connected to a deuterated sulfuric acid recovery tank; its dilute deuterated formic acid heavy aqueous solution outlet connected to the inlet pipeline of a pressurized distillation column; preferably, a dilute deuterated formic acid heavy aqueous solution storage tank is installed on this pipeline; and / or,

[0047] The pressurized distillation column has a heavy water recovery tank connected to its top heavy water outlet and a vacuum distillation column material inlet pipeline connected to its bottom material outlet; preferably, a primary purification deuterated formic acid storage tank is installed on the pipeline.

[0048] The vacuum distillation column has a secondary purified deuterated formic acid material outlet at the top and a deuterated formic acid-heavy water mixture outlet at the bottom; preferably, the deuterated formic acid-heavy water mixture outlet is connected to a dilute deuterated formic acid heavy water solution storage tank.

[0049] Preferred,

[0050] The reboiler of the atmospheric distillation apparatus is equipped with a temperature sensor; and / or

[0051] Temperature sensors are installed at both the bottom and top of the pressurized distillation column; and / or

[0052] Temperature sensors are installed at both the bottom and top of the vacuum distillation column;

[0053] More preferably,

[0054] It also includes a deuterated formic acid refining tank, whose material inlet is connected to the material outlet pipeline at the top of the vacuum distillation column;

[0055] Most preferably,

[0056] The system also includes a deuterated formic acid distillation column, whose material inlet is connected to the material outlet pipeline of the deuterated formic acid refining tank.

[0057] Compared with the prior art, the beneficial effects of the present invention are:

[0058] 1. The separation and purification method of deuterated formic acid electrolyte of the present invention can not only purify deuterated formic acid from deuterated formic acid electrolyte, but also realize the recovery and utilization of heavy water, deuterated sulfuric acid and deuterated sulfate in deuterated formic acid electrolyte, thereby improving the economic efficiency of the method.

[0059] 2. The separation and purification method of the deuterated formic acid electrolyte of the present invention can purify a 10% mass fraction heavy aqueous solution of deuterated formic acid to a high-purity deuterated formic acid with a mass fraction concentration of not less than 98%, and the purity of deuterium atoms is >99%. It is suitable for the concentration and purification of deuterated formic acid in low-concentration deuterated formic acid electrolytes.

[0060] 3. The deuterated formic acid electrolyte separation and purification system of the present invention has smooth equipment refining and material circulation, and can be operated continuously or intermittently. Attached Figure Description

[0061] Figure 1 This is a structural diagram of the separation and purification system for deuterated formic acid electrolyte in Example 2 of the present invention;

[0062] In the diagram, 1-ion exchange equipment (filled with cation exchange resin), 2-atmospheric distillation unit, 3-dilution deuterated formic acid heavy water solution storage tank, 4-pressurized distillation column, 5-first-stage purified deuterated formic acid storage tank, 6-reduced pressure distillation column, 7-deuterated formic acid refining tank, 8-deuterated formic acid distillation column, 9-heavy water recovery tank, 10-deuterated sulfuric acid recovery tank, 11-deuterated sulfate recovery tank. Detailed Implementation

[0063] In this invention, the deuterated formic acid electrolyte mainly comprises a mixture of deuterated formic acid, heavy water, deuterated sulfuric acid, and deuterated sulfate.

[0064] In this invention, the purity of deuterium atoms refers to the mass fraction of deuterium atoms relative to the total mass of hydrogen atoms, deuterium atoms, and other hydrogen isotopes.

[0065] The present invention will now be described in further detail with reference to the accompanying drawings:

[0066] This invention provides a method for separating and purifying deuterated formic acid electrolyte, comprising the following steps:

[0067] (1) The deuterated formic acid electrolyte is subjected to cation exchange, and the deuterated sulfate is adsorbed to obtain a heavy aqueous solution of deuterated formic acid containing deuterated sulfate. Specifically, in this embodiment, a cation exchange resin can be used to perform cation exchange on the deuterated formic acid electrolyte.

[0068] In a preferred embodiment of the present invention, the cation exchange resin is a strong acid type cation exchange resin. Preferably, the active groups in the cation exchange resin are selected from sulfonic acid groups or phosphate groups. More preferably, it can be selected from one of polystyrene type, polyvinyl chloride type, polysulfone type, polyphenylene ether type, and polyetherketone type cation exchange resins.

[0069] (2) The deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid is subjected to atmospheric distillation to obtain a mixed vapor of deuterated formic acid and heavy water, and deuterated sulfuric acid. Preferably, the operating temperature of atmospheric distillation in this step is 101-111°C, more preferably 101-107°C, and more preferably 101.3-102.3°C.

[0070] Deuterated sulfuric acid is transferred to a storage tank, where a portion is recycled and reused, while the remainder is returned to an ion exchange unit for ion exchange. This process regenerates the cation exchange resin and simultaneously replaces it with deuterated sulfate, allowing for its recycling. This invention directly utilizes deuterated sulfuric acid produced by atmospheric distillation to wash and regenerate the cation exchange resin, eliminating the need to introduce new deuterated reagents. This avoids cross-contamination by hydrogen isotopes and reduces purification costs.

[0071] (3) Cool the mixed steam of deuterated formic acid and heavy water to obtain a dilute deuterated formic acid heavy aqueous solution. Preferably, the mass concentration of deuterated formic acid in the dilute deuterated formic acid heavy aqueous solution is 1% to 50%, more preferably 22% to 50%.

[0072] (4) The dilute deuterated formic acid heavy aqueous solution is subjected to pressure distillation to obtain gaseous heavy water and first-stage purified deuterated formic acid. In a preferred embodiment of the present invention, the operating pressure of the pressure distillation is 0.1-0.3 MPa(G), preferably 0.15-0.2 MPa(G), the theoretical plate number of the pressure distillation is 15-40, preferably 15-30, the reflux ratio of the pressure distillation is 1-10, preferably 1-5, the operating temperature of the top of the pressure distillation column is 130.0-150.0℃, preferably 132.0-137.0℃, and the operating temperature of the bottom of the pressure distillation column is 135.0-155.0℃, preferably 138.0-143.0℃.

[0073] The heavy water in the gas phase is transferred out, allowing for its recovery and reuse. Preferably, the mass concentration of deuterated formic acid in this primary purified deuterated formic acid is 70%–90%.

[0074] (7) The first-stage purified deuterated formic acid is subjected to vacuum distillation to obtain first-stage deuterated formic acid vapor and a deuterated formic acid-heavy water mixture. The deuterated formic acid-heavy water mixture can be refluxed and reused. In a preferred embodiment of the present invention, the operating pressure of vacuum distillation is 1-20 kPa(A), preferably 1-10 kPa(A), the theoretical plate number of vacuum distillation is 20-40, preferably 20-30, the reflux ratio of vacuum distillation is 2-10, preferably 2-5, the operating temperature of the top of the vacuum distillation column is 55.0-65.0℃, preferably 56.0-59.0℃, and the operating temperature of the bottom of the vacuum distillation column is 58-68℃, preferably 60.0-63.0℃.

[0075] (6) The first deuterated formic acid vapor is cooled to obtain a second-grade purified deuterated formic acid. The mass concentration of deuterated formic acid in the second-grade purified deuterated formic acid is 93% to 97%. The second-grade purified deuterated formic acid is dehydrated, preferably by adding a desiccant. More preferably, the desiccant is selected from at least one of anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and molecular sieve. The mass ratio of the desiccant to the deuterated formic acid is 15 to 50:100, preferably 20 to 30:100.

[0076] (7) The dried, secondary purified deuterated formic acid is subjected to atmospheric distillation to obtain second deuterated formic acid vapor. The mass concentration of deuterated formic acid in the second deuterated formic acid vapor is 98% or higher. Preferably, the operating temperature of atmospheric distillation in this step is 100-105°C, more preferably 100-102°C, and even more preferably 100.8-101.3°C.

[0077] This invention first utilizes low energy consumption to separate high-purity deuterated sulfuric acid and deuterated sulfate under normal pressure, both of which can be recycled. Furthermore, the separated deuterated sulfuric acid also aids in the regeneration and washing of cation exchange resins. The method of this invention not only has low energy consumption and high recovery rate, but also does not generate isotopic wastewater or solid waste.

[0078] like Figure 1 As shown, according to the above-described method for separating and purifying deuterated formic acid electrolyte of the present invention, the present invention provides a separation and purification system for deuterated formic acid electrolyte, comprising an ion exchange device 1, an atmospheric distillation device 2, a pressurized distillation column 4, and a vacuum distillation column 8 connected in sequence by pipelines; wherein, the ion exchange device 1 is filled with cation exchange resin. Further, a dilute deuterated formic acid heavy aqueous solution storage tank 3 is provided between the atmospheric distillation device 2 and the pressurized distillation column 4; and / or, a primary purified deuterated formic acid storage tank 5 is provided between the pressurized distillation column 4 and the vacuum distillation column 8; and / or, the ion exchange device 1 is also connected to a deuterated sulfuric acid recovery tank 10 and a deuterated sulfate recovery tank 11; and / or, the pressurized distillation column 4 is also connected to a heavy water recovery tank 9.

[0079] Specifically, in this embodiment, the raw material inlet of the ion exchange device 1 is connected to the deuterated formic acid electrolyte raw material storage tank, preferably via a pipeline. The deuterated formic acid electrolyte raw material storage tank stores a deuterated formic acid electrolyte prepared by electrolysis, which mainly comprises a mixture of deuterated formic acid, heavy water, deuterated sulfuric acid, and deuterated sulfate. The deuterated formic acid electrolyte is pumped through a pipeline into the ion exchange device 1, where ion exchange occurs in the cation exchange resin to obtain a deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid. The deuterated sulfate contains M... + The ions are adsorbed by the cation exchange resin. It should be noted that the ion exchange time in the cation exchange resin needs to be determined based on the feed rate of the deuterated formic acid electrolyte, and is not specifically limited here. Furthermore, the ion exchange device 1 mentioned can be any conventional ion exchange device in the prior art, including but not limited to ion exchangers, ion exchangers, and ion exchange tanks.

[0080] In a preferred embodiment of the present invention, the cation exchange resin is a strong acid type cation exchange resin. More preferably, the active groups in the cation exchange resin are selected from sulfonic acid groups or phosphate groups. Specifically, it can be selected from one of polystyrene type, polyvinyl chloride type, polysulfone type, polyphenylene ether type, and polyetherketone type cation exchange resins.

[0081] The ion exchange device 1 has a deuterated sulfate recovery tank 11 connected to its top and a deuterated sulfuric acid recovery tank 10 connected to its bottom. Specifically, in this embodiment, the ion exchange device 1 has a deuterated sulfate recovery pipe at its top. The ion exchange device 1 is connected to the deuterated sulfate recovery tank 11 through this pipe. The ion exchange device 1 also has a deuterated sulfuric acid recovery pipe at its bottom. The ion exchange device 1 is connected to the deuterated sulfuric acid recovery tank 10 through this pipe.

[0082] An outlet for the ion-exchange material is provided on the side wall of the ion exchange device 1. This outlet is connected to the inlet of the atmospheric distillation unit 2, preferably via a pipeline. The atmospheric distillation unit 2 can be a conventional atmospheric distillation unit of the prior art, and may include an atmospheric distillation column and its conventional auxiliary equipment. The deuterated sulfuric acid outlet of the atmospheric distillation unit 2 is connected to a deuterated sulfuric acid recovery tank 10. The dilute deuterated formic acid heavy aqueous solution outlet of the atmospheric distillation unit 2 is connected to the inlet pipeline of the pressurized distillation column 4; preferably, a dilute deuterated formic acid heavy aqueous solution storage tank 3 is provided on this inlet pipeline.

[0083] The deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid, obtained through ion exchange, is pumped and piped into atmospheric distillation apparatus 2. Atmospheric distillation apparatus 2 is equipped with a heating element, which can be an electric heating mantle or heat transfer oil. Those skilled in the art know that the boiling point of deuterated formic acid is 100.8℃, the boiling point of heavy water is 101.4℃, and the boiling point of deuterated sulfuric acid is 330.0±11.0℃. By utilizing the difference in boiling points of these three substances, the temperature of atmospheric distillation apparatus 2 is controlled so that the low-boiling-point deuterated formic acid and heavy water evaporate and move to the top of atmospheric distillation apparatus 2, while the high-boiling-point deuterated sulfuric acid remains in the liquid phase at the bottom of atmospheric distillation apparatus 2. The operating temperature of atmospheric distillation apparatus 2 is 101–111℃, preferably 101–107℃, and more preferably 101.3–102.3℃.

[0084] The reboiler of the atmospheric distillation unit 2 is equipped with a temperature sensor. When the temperature of the reboiler of the atmospheric distillation unit 2 rises sharply and exceeds 110°C, the heating operation is stopped. After the temperature cools down to room temperature, the bottom valve of the reboiler of the atmospheric distillation unit 2 is opened, and the deuterated sulfuric acid is transferred to the deuterated sulfuric acid recovery pipeline and then stored in the deuterated sulfuric acid recovery tank 10. It should be noted that the top of the atmospheric distillation unit 2 is connected to the dilute deuterated formic acid heavy aqueous solution storage tank 3. Steam enters the dilute deuterated formic acid heavy aqueous solution storage tank 3 as soon as it is generated, and the steam is not transferred to the dilute deuterated formic acid heavy aqueous solution storage tank 3 only after the heating operation is stopped.

[0085] The top of the atmospheric distillation unit 2 is connected to the dilute deuterated formic acid heavy aqueous solution storage tank 3 via a pipeline. The distilled deuterated formic acid and heavy water mixture vapor enters the dilute deuterated formic acid heavy aqueous solution storage tank 3 through this pipeline. After the gaseous formic acid and heavy water enter the dilute deuterated formic acid heavy aqueous solution storage tank 3, since the temperature of the storage tank 3 is room temperature, the gaseous deuterated formic acid and heavy water undergo a phase transition to obtain the dilute deuterated formic acid heavy aqueous solution. The mass concentration of deuterated formic acid in this dilute deuterated formic acid heavy aqueous solution is 1% to 50%, preferably 22% to 50%.

[0086] The deuterated sulfuric acid in the deuterated sulfuric acid recovery pipeline enters the deuterated sulfuric acid recovery tank 10, allowing for its recovery and reuse. When the separation and purification system for the deuterated formic acid electrolyte stops operating, a portion of the deuterated sulfuric acid in the recovery tank 10 enters the ion exchange device 1, enabling the recovery and reuse of deuterated sulfate. The deuterated sulfuric acid entering the ion exchange device 1 undergoes another cation exchange, reducing the D in the deuterated sulfuric acid. + Adsorbed by cation exchange resin, M that was originally adsorbed in the cation exchange resin + The deuterated sulfate is obtained by displacement. This deuterated sulfate is then fed into the deuterated sulfate recovery tank 11 through the deuterated sulfate recovery pipeline, allowing the deuterated sulfate to be recovered and reused.

[0087] It is important to emphasize that, as mentioned above, when the temperature of the reboiler in atmospheric distillation unit 2 rises sharply and exceeds 110°C, the heating operation is stopped. After the temperature cools to room temperature, the bottom valve of the reboiler in atmospheric distillation unit 2 is opened, transferring the deuterated sulfuric acid into the deuterated sulfuric acid recovery pipeline and storing it in the deuterated sulfuric acid recovery tank 10. At this time, the deuterated sulfuric acid does not enter the ion exchange device 1. The cation exchange resin will only be regenerated when the separation and purification system for the deuterated formic acid electrolyte stops operating. At this time, the deuterated sulfuric acid in the deuterated sulfuric acid recovery tank 10 is transported to the ion exchange device 1 via a transfer pump. The amount of deuterated sulfuric acid used for regeneration in the ion exchange device 1 must be sufficient to achieve a preset conductivity or pH value for the cation exchange resin. Once the regenerated cation exchange resin reaches the preset requirements, the transfer pump is turned off to prevent further deuterated formic acid from entering the ion exchange device 1.

[0088] A dilute deuterated formic acid heavy water solution storage tank 3 is connected to a pressurized distillation column 4 via a pipeline. When the transfer pump is started, the dilute deuterated formic acid heavy water solution in the storage tank 3 enters the pressurized distillation column 4 through the pipeline. The pressurized distillation column 4 can be a commonly used pressurized distillation column in the prior art and may include conventional auxiliary equipment. Temperature sensors are installed at both the bottom and top of the pressurized distillation column 4. Based on the phase diagram of deuterated formic acid-heavy water, the temperature, pressure, number of plates, and reflux ratio of the pressurized distillation column 4 are controlled so that heavy water is distilled from the top of the pressurized distillation column 4, and primary purified deuterated formic acid is collected from the bottom of the pressurized distillation column 4 at the current pressure. It should be noted that the mass concentration of the primary purified deuterated formic acid at the current pressure is 70%–90%.

[0089] In a preferred embodiment of the present invention, the operating pressure of the pressurized distillation column 4 is 0.1–0.3 MPa(G), preferably 0.15–0.2 MPa(G); the number of theoretical plates of the pressurized distillation column 4 is 15–40, preferably 15–30; the reflux ratio of the pressurized distillation column 4 is 1–10, preferably 1–5; the operating temperature of the top of the pressurized distillation column 4 is 130.0–150.0 °C, preferably 132.0–137.0 °C; and the operating temperature of the bottom of the pressurized distillation column 4 is 135.0–155.0 °C, preferably 138.0–143.0 °C.

[0090] When the temperature at the top of the pressurized distillation column 4 reaches 138°C, heating is stopped. The column is allowed to cool to room temperature before the bottom valve of the reboiler is opened, transferring the first-stage purified deuterated formic acid to the first-stage purified deuterated formic acid storage tank 5. It should be noted that the pressurized distillation column 4 has a heavy water outlet connected to a heavy water recovery tank 9 at the top, and its reboiler material outlet connected to the material inlet pipeline of the vacuum distillation column 6. Preferably, the first-stage purified deuterated formic acid storage tank 5 is installed on this inlet pipeline. The top of the pressurized distillation column 4 is connected to the heavy water recovery tank 9; steam enters the heavy water recovery tank 9 as soon as it is available, not only after heating is stopped.

[0091] The top of the pressurized distillation column 4 is connected to the heavy water recovery tank 9 via a pipeline. The distilled heavy water enters the heavy water recovery tank 9 through this pipeline, allowing the heavy water to be recovered and reused. The bottom of the pressurized distillation column 4 is connected to the primary purified deuterated formic acid storage tank 5 via a pipeline. When the transfer pump is started, the primary purified deuterated formic acid enters the primary purified deuterated formic acid storage tank 5 through this pipeline. The setup of the dilute deuterated formic acid heavy water solution storage tank 3 and the primary purified deuterated formic acid storage tank 5 allows the separation and purification system of deuterated formic acid electrolyte to operate continuously or intermittently.

[0092] A primary purified deuterated formic acid storage tank 5 is connected to a vacuum distillation column 6 via a pipeline. When the transfer pump is started, the primary purified deuterated formic acid in the storage tank 5 enters the vacuum distillation column 6. The vacuum distillation column 6 can be selected from conventional distillation columns of the prior art and may include conventional auxiliary equipment. Temperature sensors are installed at both the bottom and top of the vacuum distillation column 6. Based on the phase diagram of deuterated formic acid-heavy water, the temperature, pressure, number of plates, and reflux ratio of the vacuum distillation column 6 are controlled so that the first-stage deuterated formic acid vapor is distilled from the top of the column, and the deuterated formic acid-heavy water mixture at the current pressure is collected from the bottom of the column. It should be noted that the mass concentration of deuterated formic acid in the deuterated formic acid-heavy water mixture at the current pressure is 50%.

[0093] The vacuum distillation column 6 has a secondary purified deuterated formic acid material outlet at its top and a deuterated formic acid-heavy water mixture outlet at its bottom; preferably, the deuterated formic acid-heavy water mixture outlet is connected to a dilute deuterated formic acid heavy water solution storage tank 3.

[0094] In a preferred embodiment of the present invention, the operating pressure of the vacuum distillation column 6 is 1-20 kPa(A), preferably 1-10 kPa(A); the number of theoretical plates of the vacuum distillation column 6 is 20-40, preferably 20-30; the reflux ratio of the vacuum distillation column 6 is 2-10, preferably 2-5; the operating temperature at the top of the vacuum distillation column 6 is 55.0-65.0℃, preferably 56.0-59.0℃; and the operating temperature at the bottom of the vacuum distillation column 6 is 58-68℃, preferably 60.0-63.0℃.

[0095] When the temperature at the top of the vacuum distillation column 6 reaches 60.0℃, heating is stopped. After cooling to room temperature, the bottom valve of the reboiler of the vacuum distillation column 6 is opened, transferring the 50% (w / w) deuterated formic acid-heavy water mixture into the dilute deuterated formic acid heavy water solution storage tank 3. It should be noted that the top of the vacuum distillation column 6 is connected to the deuterated formic acid refining tank 7; steam enters the deuterated formic acid refining tank 7 as soon as it is available, not only after heating is stopped.

[0096] When deuterated formic acid and heavy water are in an azeotropic state, further concentration of deuterated formic acid is limited by the azeotropic system. According to the phase diagram of deuterated formic acid and heavy water, higher pressure results in a higher concentration of deuterated formic acid in the azeotrope, while lower pressure results in a lower concentration. Therefore, the concentration of deuterated formic acid in the bottom azeotrope can be increased by increasing the pressure of the distillation system; higher pressure yields higher purity deuterated formic acid. Conversely, the concentration of deuterated formic acid in the overhead vapor phase can be increased by decreasing the pressure of the distillation system; lower pressure yields higher purity deuterated formic acid.

[0097] However, higher pressure leads to higher reboiler temperatures. Excessive temperature causes a sharp increase in the corrosion of equipment by deuterated formic acid, demanding increasingly stringent corrosion resistance from equipment materials. Furthermore, deuterated formic acid may decompose under excessive pressure or temperature. Therefore, considering both equipment investment and distillation costs, a two-stage pressure-swing azeotropic distillation method can be adopted industrially. First, pressurized azeotropic distillation is performed, increasing the concentration of the dilute deuterated formic acid heavy water solution in the reboiler of pressurized distillation column 4. Then, the first-stage purified deuterated formic acid, concentrated under high pressure, is fed into vacuum distillation column 6, reducing the concentration of deuterated formic acid in the reboiler of vacuum distillation column 6. The remaining deuterated formic acid-heavy water mixture in the reboiler of vacuum distillation column 6 is returned to pressurized distillation column 4 for further concentration. This cyclical operation ultimately achieves the separation of deuterated formic acid and heavy water.

[0098] In a preferred embodiment of the present invention, the system further includes a deuterated formic acid refining tank 7, the material inlet of which is connected to the material outlet pipeline at the top of the vacuum distillation column 6; the first deuterated formic acid vapor at the top of the vacuum distillation column 6 enters the deuterated formic acid refining tank 7 through this pipeline. After entering the deuterated formic acid refining tank 7, the first deuterated formic acid vapor undergoes a phase transition due to the ambient temperature of the tank, yielding secondary purified deuterated formic acid. The mass concentration of this secondary purified deuterated formic acid is 93% to 97%. The bottom of the vacuum distillation column 6 is connected to a dilute deuterated formic acid heavy water solution storage tank 3 via a pipeline, and the deuterated formic acid-heavy water mixture with a mass concentration of 50% at the bottom of the vacuum distillation column 6 enters the dilute deuterated formic acid heavy water solution storage tank 3 through this pipeline for recycling.

[0099] The deuterated formic acid refining tank 7 is equipped with a feed inlet, through which a desiccant can be added and stirred to perform a final dehydration of the secondary purified deuterated formic acid. Preferably, the desiccant is selected from at least one of anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and molecular sieve.

[0100] In a preferred embodiment of the present invention, the system further includes a deuterated formic acid distillation column 8, the material inlet of which is connected to the material outlet pipeline of the deuterated formic acid refining tank 7; the secondary purified deuterated formic acid in the deuterated formic acid refining tank 7 enters the deuterated formic acid distillation column 8 through this pipeline. Utilizing the boiling point difference between deuterated formic acid and heavy water, the temperature of the deuterated formic acid distillation column 8 is controlled, causing the low-boiling-point deuterated formic acid to evaporate and move to the top of the deuterated formic acid distillation column 8, while the high-boiling-point heavy water remains in the liquid phase and stays at the bottom of the deuterated formic acid distillation column 8. The deuterated formic acid distillation column 8 can be selected from commonly used distillation columns in the prior art and may include conventional auxiliary equipment. Temperature sensors are installed at both the bottom and top of the deuterated formic acid distillation column 8; operation is stopped when the temperature of the bottom of the deuterated formic acid distillation column 8 exceeds 105°C. After passing through the deuterated formic acid distillation column 8, a second deuterated formic acid vapor (with a mass concentration of 98% or higher) is obtained at the top of the column, and a small amount of heavy water is obtained at the bottom of the column. The operating temperature of the deuterated formic acid distillation column 8 is 100–105°C, preferably 100–102°C, and more preferably 100.8–101.3°C.

[0101] More specifically, the present invention also provides a method for separating and purifying deuterated formic acid electrolyte using the above-described equipment, comprising the following steps:

[0102] (1) The deuterated formic acid electrolyte enters the ion exchange device 1 from the deuterated formic acid electrolyte raw material storage tank, and ion exchange is carried out in the ion exchange device 1. The deuterated sulfate is adsorbed to obtain a deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid. The deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid is transferred to the atmospheric distillation device 2.

[0103] (2) In the atmospheric distillation apparatus 2, the operating temperature of the atmospheric distillation apparatus 2 is controlled. A mixture of deuterated formic acid and heavy water vapor is obtained at the top of the atmospheric distillation apparatus 2, and deuterated sulfuric acid is obtained at the bottom of the atmospheric distillation apparatus 2. When the temperature of the bottom of the atmospheric distillation apparatus 2 rises sharply and exceeds 110°C, the operation is stopped.

[0104] The mixed steam from the top of the atmospheric distillation unit 2 is transferred to the dilute deuterated formic acid heavy aqueous solution storage tank 3, and the deuterated sulfuric acid from the bottom of the atmospheric distillation unit 2 is transferred to the deuterated sulfuric acid recovery pipeline and then to the deuterated sulfuric acid recovery tank 10. When cation exchange resin regeneration is required, the pump in the deuterated sulfuric acid recovery pipeline is controlled to allow a portion of the deuterated sulfuric acid in the deuterated sulfuric acid recovery tank 10 to enter the ion exchange unit 1. This achieves the regeneration of the cation exchange resin on the one hand, and the displaced deuterated sulfate enters the deuterated sulfate recovery tank 11, allowing the deuterated sulfate to be recovered and reused.

[0105] (3) In the dilute deuterated formic acid heavy aqueous solution storage tank 3, the gaseous deuterated formic acid and heavy water undergo a phase transition to obtain a dilute deuterated formic acid heavy aqueous solution. The dilute deuterated formic acid heavy aqueous solution is transferred to the pressurized distillation column 4. Preferably, the mass concentration of deuterated formic acid in the dilute deuterated formic acid heavy aqueous solution is 1% to 50%, more preferably 22% to 50%.

[0106] (4) In the pressurized distillation column 4, the temperature, pressure, number of plates, and reflux ratio of the pressurized distillation column 4 are controlled so that heavy water is distilled out at the top of the pressurized distillation column 4, and the first-stage purified deuterated formic acid under the current pressure is collected from the bottom of the pressurized distillation column 4. When the temperature at the top of the pressurized distillation column 4 rises to 138°C, the operation is stopped.

[0107] In a preferred embodiment of the present invention, the operating pressure of the pressurized distillation column 4 is 0.15 to 0.2 MPa(G), the number of theoretical plates of the pressurized distillation column 4 is 15 to 40, the reflux ratio of the pressurized distillation column 4 is 1 to 5, the operating temperature of the top of the pressurized distillation column 4 is 132.0 to 137.0°C, and the operating temperature of the bottom of the pressurized distillation column 4 is 138.0 to 143.0°C.

[0108] The heavy water at the top of pressurized distillation column 4 is transferred to heavy water recovery tank 9, allowing for its recycling. The first-stage purified deuterated formic acid from the bottom of pressurized distillation column 4 enters the first-stage purified deuterated formic acid storage tank 5. Preferably, the mass concentration of deuterated formic acid in this first-stage purified deuterated formic acid is 70% to 90%.

[0109] (5) The first-stage purified deuterated formic acid in the storage tank 5 enters the vacuum distillation column 6. In the vacuum distillation column 6, the temperature, pressure, number of plates, and reflux ratio are controlled so that the first-stage deuterated formic acid vapor is distilled from the top of the column, and the deuterated formic acid-heavy water mixture at the current pressure is collected from the bottom of the column. When the temperature at the top of the column reaches 60.0℃, the operation is stopped.

[0110] In a preferred embodiment of the present invention, the operating pressure of the vacuum distillation column 6 is 1-10 kPa(A), the number of theoretical plates of the vacuum distillation column 6 is 20-40, the reflux ratio of the vacuum distillation column 6 is 2-10, the operating temperature of the top of the vacuum distillation column 6 is 56.0-59.0°C, and the operating temperature of the bottom of the vacuum distillation column 6 is 60.0-63.0°C.

[0111] The first deuterated formic acid vapor at the top of vacuum distillation column 6 enters the deuterated formic acid refining tank 7. The 50% deuterated formic acid-heavy water mixture at the bottom of vacuum distillation column 6 enters the dilute deuterated formic acid heavy water solution storage tank 3 for recycling.

[0112] (6) In the deuterated formic acid refining tank 7, the first deuterated formic acid vapor undergoes a phase transition to obtain secondary purified deuterated formic acid (mass concentration of 93%–97%). A desiccant is added to the deuterated formic acid refining tank 7 to perform final dehydration on the secondary purified deuterated formic acid. Preferably, the desiccant is selected from at least one of anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and molecular sieve. The dehydrated secondary purified deuterated formic acid enters the deuterated formic acid distillation column 8.

[0113] (7) In the deuterated formic acid distillation column 8, the operating temperature of the deuterated formic acid distillation column 8 is controlled. The second deuterated formic acid vapor (mass concentration of 98% or higher) is obtained at the top of the deuterated formic acid distillation column 8, and a small amount of heavy water is obtained at the bottom of the deuterated formic acid distillation column 8. When the temperature of the bottom of the deuterated formic acid distillation column 8 exceeds 105°C, the operation is stopped.

[0114] Example 1

[0115] This embodiment uses the above-described appendix. Figure 1 The separation and purification system for the deuterated formic acid electrolyte is used, specifically including the following steps:

[0116] (1) The deuterated formic acid electrolyte in the raw material storage tank enters the ion exchange device 1 filled with cation exchange resin, where ion exchange occurs. Deuterated sulfate is adsorbed, resulting in a deuterated formic acid heavy aqueous solution containing deuterated sulfate. The mass concentration of deuterated formic acid in the electrolyte is 10%. In this embodiment, the cation exchange resin is specifically a polystyrene sulfonic acid type resin (commercially available).

[0117] (2) The deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid enters the atmospheric distillation apparatus 2 and is distilled at atmospheric pressure to obtain a mixed vapor of deuterated formic acid and heavy water, and deuterated sulfuric acid. The temperature of atmospheric distillation is 110℃.

[0118] The deuterated sulfuric acid is transferred to the deuterated sulfuric acid recovery pipeline. Part of it enters the deuterated sulfuric acid recovery tank 10 for recycling, while the other part enters the ion exchange equipment 1 for ion exchange. On the one hand, the cation exchange resin is regenerated, and on the other hand, deuterated sulfate is obtained by replacement. The deuterated sulfate is then transferred to the deuterated sulfate recovery tank 11 so that the deuterated sulfate can be recycled and reused.

[0119] (3) The mixed vapor of deuterated formic acid and heavy water enters the dilute deuterated formic acid heavy water storage tank 3 to obtain a dilute deuterated formic acid heavy water solution with a mass concentration of 50% of deuterated formic acid.

[0120] (4) The dilute deuterated formic acid heavy aqueous solution enters the pressurized distillation column 4 for pressurized distillation, yielding heavy water in the gas phase and first-stage purified deuterated formic acid at the current pressure. The mass concentration of deuterated formic acid in the first-stage purified deuterated formic acid is 80%. The pressure of the pressurized distillation column 4 is 0.15 MPa(G), the number of theoretical plates of the pressurized distillation column 4 is 20, the reflux ratio of the pressurized distillation column 4 is 5, the operating temperature of the top of the pressurized distillation column 4 is 135℃, and the operating temperature of the bottom of the pressurized distillation column 4 is 140℃.

[0121] The gaseous heavy water is transferred to the heavy water recovery tank 9, so that the heavy water can be recycled and reused.

[0122] (5) The first-stage purified deuterated formic acid is first transferred to the first-stage purified deuterated formic acid storage tank 5, and then transferred to the vacuum distillation column 6. The first-stage purified deuterated formic acid is subjected to vacuum distillation to obtain first-stage deuterated formic acid vapor and deuterated formic acid-heavy water mixture. The mass concentration of deuterated formic acid in the first-stage deuterated formic acid vapor is 95%; the mass concentration of deuterated formic acid in the deuterated formic acid-heavy water mixture is 50%. The operating pressure of the vacuum distillation column 6 is 10 kPa (A), the theoretical plate number of the vacuum distillation column 6 is 30, the reflux ratio of the vacuum distillation column 6 is 3, the operating temperature of the top of the vacuum distillation column 6 is 59°C, and the operating temperature of the bottom of the vacuum distillation column 6 is 63°C.

[0123] The deuterated formic acid-heavy water mixture can be transferred to the dilute deuterated formic acid heavy water solution storage tank 3 for reflux and reuse.

[0124] (6) The first deuterated formic acid vapor enters the deuterated formic acid refining tank 7, and anhydrous sodium sulfate is added to it to dehydrate it, so as to obtain secondary purified deuterated formic acid with a mass concentration of 95.2%.

[0125] (7) The dried secondary purified deuterated formic acid is fed into the deuterated formic acid distillation column 8, where it is distilled at atmospheric pressure at a temperature of 102°C. A deuterated formic acid product with a mass concentration of 98.5% is obtained.

[0126] It should be noted that the mass concentration of deuterated formic acid was determined by GC-MS.

[0127] Example 2

[0128] This experimental example is basically the same as Experimental Example 1, with the only difference being:

[0129] (1) The operating pressure of vacuum distillation column 6 is 5 kPa (A);

[0130] (2) The mass concentration of deuterated formic acid in the secondary purification tank 7 was 96.4%;

[0131] (3) The obtained deuterated formic acid product has a mass concentration of 98.7%.

[0132] Example 3

[0133] This experimental example is basically the same as Experimental Example 1, with the only difference being:

[0134] (1) The operating pressure of vacuum distillation column 6 is 1 kPa (A);

[0135] (2) The mass concentration of deuterated formic acid in the secondary purification tank 7 is 97.8%;

[0136] (3) The obtained deuterated formic acid product has a mass concentration of 98.9%.

[0137] Example 4

[0138] This experimental example is basically the same as Experimental Example 1, with the only difference being:

[0139] (1) The operating pressure of pressurized distillation column 4 is 0.2 MPa (G);

[0140] (2) The mass concentration of deuterated formic acid in the secondary purification tank 7 is 96.0%;

[0141] (3) The obtained deuterated formic acid product has a mass concentration of 98.6%.

[0142] Example 5

[0143] This experimental example is basically the same as Experimental Example 1, with the only difference being:

[0144] (1) The operating pressure of pressurized distillation column 4 is 0.2 MPa (G);

[0145] (2) The operating pressure of vacuum distillation column 6 is 5 kPa (A);

[0146] (3) The mass concentration of deuterated formic acid in the secondary purification tank 7 is 97.1%;

[0147] (4) The obtained deuterated formic acid product has a mass concentration of 98.8%.

[0148] Example 6

[0149] This experimental example is basically the same as Experimental Example 1, with the only difference being:

[0150] (1) The operating pressure of pressurized distillation column 4 is 0.2 MPa (G);

[0151] (2) The operating pressure of vacuum distillation column 6 is 1 kPa (A);

[0152] (3) The mass concentration of deuterated formic acid in the secondary purification tank 7 is 98.2%;

[0153] (4) The obtained deuterated formic acid product has a mass concentration of 99.0%.

[0154] Example 7

[0155] This experimental example is basically the same as Experimental Example 1, with the only difference being:

[0156] (1) The mass concentration of deuterated formic acid in the deuterated formic acid electrolyte is 20%;

[0157] (2) The mass concentration of deuterated formic acid in the secondary purification tank 7 is 95.3%;

[0158] (3) The obtained deuterated formic acid product has a mass concentration of 98.7%.

[0159] It should be noted that the mass concentration of deuterated formic acid in the electrolyte is not the same in Examples 1 and 7, but the mass concentration of deuterated formic acid after secondary purification in Examples 1 and 7 is similar. This is because the actual factor affecting the mass concentration of deuterated formic acid after secondary purification is not the initial mass concentration of deuterated formic acid in the electrolyte, but rather the condition parameters of atmospheric distillation, pressurized distillation, and vacuum distillation. A lower initial mass concentration of deuterated formic acid in the electrolyte will only increase the energy consumption of the atmospheric distillation, pressurized distillation, and vacuum distillation processes.

[0160] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0161] In the description of this invention, unless otherwise stated, the terms "upper," "lower," "left," "right," "inner," "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0162] The above technical solution is only one embodiment of the present invention. For those skilled in the art, based on the principles disclosed in the present invention, it is easy to make various types of improvements or modifications, and not limited to the technical solutions described in the specific embodiments of the present invention. Therefore, the foregoing description is only a preferred option and is not restrictive.

Claims

1. A method for separating and purifying deuterated formic acid electrolyte, characterized in that, Includes the following steps: (1) The deuterated formic acid electrolyte was subjected to cation exchange to obtain a deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid; (2) The deuterated formic acid heavy aqueous solution containing deuterated sulfuric acid is subjected to atmospheric pressure distillation to obtain dilute deuterated formic acid heavy aqueous solution and deuterated sulfuric acid, respectively. (3) The dilute deuterated formic acid heavy aqueous solution was subjected to pressure distillation to obtain heavy water and first-stage purified deuterated formic acid, respectively. (4) The first-stage purified deuterated formic acid is subjected to vacuum distillation to obtain second-stage purified deuterated formic acid and a deuterated formic acid-heavy water mixture, respectively. Preferably, the deuterated formic acid-heavy water mixture is refluxed into a dilute deuterated formic acid heavy water solution.

2. The method according to claim 1, characterized in that: In step (1), Cation exchange is performed using cation exchange resin; Preferably, the cation exchange resin is a strong acid type cation exchange resin; More preferably, the active groups of the cation exchange resin are selected from sulfonic acid groups and / or phosphate groups; Most preferably, the cation exchange resin is selected from any one of polystyrene-type, polyvinyl chloride-type, polysulfone-type, polyphenylene ether-type, and polyetherketone-type cation exchange resins.

3. The method according to claim 1, characterized in that: In step (2), The operating temperature for atmospheric distillation is 101–111°C, preferably 101–107°C, and more preferably 101.3–102.3°C; Preferably, the deuterated sulfuric acid is refluxed to the cation exchange resin for ion exchange to remove the deuterated sulfate.

4. The method according to claim 1, characterized in that: In step (3), The operating pressure for pressurized distillation is 0.1–0.3 MPa(G), preferably 0.15–0.2 MPa(G); and / or The theoretical plate number of pressurized distillation is 15–40, preferably 15–30; and / or The reflux ratio for pressurized distillation is 1-10, preferably 1-5; and / or The operating temperature at the top of the pressurized distillation column is 130.0–150.0℃, preferably 132.0–137.0℃; and / or The operating temperature of the reboiler in the pressurized distillation column is 135.0–155.0℃, preferably 138.0–143.0℃.

5. The method according to claim 1, characterized in that: In step (4), The operating pressure for vacuum distillation is 1–20 kPa(A), preferably 1–10 kPa(A); and / or The theoretical plate number of vacuum distillation is 20–40, preferably 20–30; and / or The reflux ratio for vacuum distillation is 2–10, preferably 2–5; and / or The operating temperature at the top of the reduced-pressure distillation column is 55.0–65.0℃, preferably 56.0–59.0℃; and / or The operating temperature of the reboiler in vacuum distillation is 58–68°C, preferably 60.0–63.0°C.

6. The method according to any one of claims 1 to 5, characterized in that... It also includes the following steps: (5) Dehydrate the secondary purified deuterated formic acid obtained in step (4), preferably by adding a desiccant; (6) The dehydrated secondary purified deuterated formic acid is subjected to atmospheric pressure distillation to obtain deuterated formic acid with a mass concentration of not less than 98%.

7. The method according to claim 6, characterized in that: In step (5), The desiccant is selected from at least one of anhydrous copper sulfate, anhydrous sodium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and molecular sieves; and / or The mass ratio of the desiccant to the deuterated formic acid is (15-50):100, preferably (20-30):

100.

8. The method according to claim 6, characterized in that: In step (6) The operating temperature for atmospheric distillation is 100–105°C, preferably 100–102°C, and more preferably 100.8–101.3°C.

9. A separation and purification system for deuterated formic acid electrolyte, characterized in that... It includes an ion exchange device, an atmospheric distillation unit, a pressurized distillation column, and a vacuum distillation column connected in sequence by pipelines, wherein the ion exchange device is filled with cation exchange resin.

10. The system according to claim 9, characterized in that: The feed inlet of the ion exchange equipment is connected to the deuterated formic acid electrolyte feed tank, and the outlet of the ion-exchanged material on its side wall is connected to the inlet of the atmospheric distillation unit; a deuterated sulfate recovery tank is connected to the top of the ion exchange equipment, and a deuterated sulfuric acid recovery tank is connected to its bottom; and / or, The atmospheric distillation apparatus has a deuterated sulfuric acid outlet connected to a deuterated sulfuric acid recovery tank; its dilute deuterated formic acid heavy aqueous solution outlet connected to the inlet pipeline of a pressurized distillation column; preferably, a dilute deuterated formic acid heavy aqueous solution storage tank is installed on this pipeline; and / or, The pressurized distillation column has a heavy water recovery tank connected to its top heavy water outlet and a vacuum distillation column material inlet pipeline connected to its bottom material outlet; preferably, a primary purification deuterated formic acid storage tank is installed on the pipeline. The vacuum distillation column has a secondary purified deuterated formic acid material outlet at the top and a deuterated formic acid-heavy water mixture outlet at the bottom; preferably, the deuterated formic acid-heavy water mixture outlet is connected to a dilute deuterated formic acid heavy water solution storage tank. Preferred, The reboiler of the atmospheric distillation apparatus is equipped with a temperature sensor; and / or Temperature sensors are installed at both the bottom and top of the pressurized distillation column; and / or Temperature sensors are installed at both the bottom and top of the vacuum distillation column; More preferably, It also includes a deuterated formic acid refining tank, whose material inlet is connected to the material outlet pipeline at the top of the vacuum distillation column; Most preferably, The system also includes a deuterated formic acid distillation column, whose material inlet is connected to the material outlet pipeline of the deuterated formic acid refining tank.

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