Preparation method of deuterated ammonia
By using multiple exchange, drying and calcining steps of decomposed ammonium salts and heavy water in the preparation of decomposed ammonium salts, the problem of expensive magnesium nitride and difficult to separate by-products is solved, and efficient preparation and resources of high-purity decomposed ammonium is achieved. Maximized utilization reduces production costs and process complexity.
Patent Information
- Application Number
- CN202411478870.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-22
- Publication Date
- 2024-12-27
AI Technical Summary
In the existing deuterated ammonia preparation methods, magnesium nitride is expensive as a raw material and the supply is unstable. The by-products generated during the reaction increase the difficulty of the process, resulting in waste of resources and difficult separation of high-purity deuterated ammonia gases, and high production costs.
The decomposed ammonium salt is used for multiple exchanges in heavy water. After drying, calcining and secondary drying, the preparation process of deuterated ammonium salt is optimized, the purity of the product and resource utilization rate are improved, and the production cost is reduced.
It realizes the preparation of high-purity deuterated ammonia, reduces production costs, improves resource utilization and environmental protection of process, and is suitable for high-demand application fields.
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Figure CN119191315A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparation of deuterated compounds, and in particular to a method for preparing deuterated ammonia. Background Art
[0002] As an important isotope labeling reagent, deuterated ammonia has irreplaceable application value in the fields of chemical synthesis and the electronics industry. In the process of chemical synthesis, deuterated ammonia can be used as an important precursor for the introduction of amino groups and is widely used in the synthesis of various deuterated drugs and their key intermediates. Especially in the electronics industry, deuterated ammonia plays a vital role in the manufacturing process of memory chips. It is mainly used to deposit silicon nitride (SiN) and silicon oxynitride (SiON) films. These thin film materials play an insulating and protective role in microelectronic devices.
[0003] At present, the main method for preparing deuterated ammonia is to use magnesium nitride (Mg3N2) as a raw material and react it with heavy water (D2O). However, this production process has several limitations. First, magnesium nitride (Mg3N2) as a raw material is expensive and unstable in supply, which will lead to high production costs of the final product; secondly, in the process of the reaction between magnesium nitride (Mg3N2) and heavy water (D2O), a water-insoluble byproduct, heavy magnesium hydroxide (Mg(OD)2), will be produced, which not only increases the technical difficulty of material mixing and stirring, but also limits the large-scale production of the process; thirdly, part of the heavy hydrogen (D) element will be fixed in the by-product and cannot be fully utilized, resulting in a waste of resources; finally, since the reaction system inevitably contains water, it becomes extremely difficult to separate high-purity deuterated ammonia gas from the reaction product.
[0004] Therefore, it is urgent to develop an efficient and economical method for preparing deuterated ammonia to obtain high-purity deuterated ammonia gas. Summary of the invention
[0005] In view of this, the present invention proposes a preparation method of deuterated ammonia with low production cost, high resource utilization rate and the ability to effectively separate high-purity deuterated ammonia.
[0006] The present invention provides a method for preparing deuterated ammonia, comprising: exchanging a decomposable ammonium salt in heavy water for multiple times to obtain a deuterated ammonium salt; drying, roasting, and drying the deuterated ammonium salt in sequence to obtain deuterated ammonia;
[0007] The exchange process comprises: mixing the decomposable ammonium salt and heavy water, stirring, evaporating, obtaining the semi-deuterated ammonium salt, and condensing and recovering the semi-heavy water to complete one exchange.
[0008] By adopting the above technical solution, multiple exchanges not only optimize the preparation process of deuterated ammonium salts, improve the purity and production efficiency of the products, but also achieve effective recovery of resources and simplification of subsequent processing.
[0009] Furthermore, the decomposable ammonium salt is selected from one of ammonium nitrate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, ammonium oxalate or ammonium citrate.
[0010] By adopting the above technical solution, not only can different process requirements be met, but also the reaction efficiency and product quality can be improved, while reducing production costs, making the entire preparation process more economical and environmentally friendly.
[0011] Furthermore, the mass ratio of the decomposable ammonium salt to the heavy water is 1:(4-10).
[0012] By adopting the above technical solution, while ensuring the reaction efficiency, it is possible to achieve multiple goals such as low-cost control, simple operation and environmental friendliness.
[0013] Furthermore, during the exchange process, after mixing, the pH value of the solution is 2 to 9.
[0014] By adopting the above technical solution, the selectivity and efficiency of the reaction can be improved, while the operating conditions can be simplified and the purity of the product can be improved. In addition, the safety and stability of the equipment can be maintained.
[0015] Furthermore, during the exchange process, the exchange temperature is 0 to 40° C., and the number of exchanges is 1 to 5 times.
[0016] Furthermore, the primary drying temperature is 20-80° C., the time is 4-24 hours, and the absolute pressure is 0-0.1 MPa.
[0017] Furthermore, the calcination temperature is 120-500° C. and the calcination time is 2-5 hours.
[0018] Furthermore, the secondary drying includes a first stage drying and a second stage drying; the first stage drying uses an alkaline desiccant, and the second stage drying uses a neutral desiccant.
[0019] By adopting the above technical solution, the two-stage drying process can significantly improve the purity and stability of the final product, while simplifying the operating process and improving safety.
[0020] Furthermore, the alkaline desiccant is selected from one or more of magnesium nitride, soda lime, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, calcium oxide or sodium.
[0021] By adopting the above technical solution, the alkaline desiccant can effectively remove the acidic impurities or by-products remaining in the product, for example, the acidic by-products that may be produced during the exchange process, thereby improving the purity of the product.
[0022] Furthermore, the neutral desiccant is selected from one or more of alumina, 3A molecular sieve, 5A molecular sieve or 13X molecular sieve.
[0023] By adopting the above technical solutions, the neutral desiccant can further remove moisture without introducing additional acidic or alkaline impurities, ensuring the high purity of the final product. Alumina has strong water absorption properties and can effectively remove residual moisture and improve the dryness of the product; molecular sieves have good adsorption properties and high selectivity, and can selectively adsorb moisture according to different molecular sizes. In addition, both alumina and molecular sieves can be regenerated by heating, which means they can be used multiple times, reducing production costs.
[0024] The method for preparing deuterated ammonia provided by the present invention has the following beneficial effects compared with the prior art:
[0025] The method for preparing deuterated ammonia of the present invention has efficient and mild reaction conditions, ensures high purity and high deuterium content of the final product through multiple exchange reactions, and significantly improves the purity of the final product by combining the steps of primary drying, roasting and secondary drying. In addition, the present invention realizes the maximum utilization of resources, reduces the generation of by-products or harmful substances, and improves the environmental protection of the entire process through the steps of multiple exchanges and evaporation to recover semi-heavy water, secondary drying and purification of products.
[0026] The purity of the deuterated ammonia prepared by the invention is not less than 99.5%, and can be applied to application fields with high requirements. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0028] Figure 1 This is a production flow chart for preparing deuterated ammonia in Example 1 of the present invention;
[0029] Figure 2 This is the mass spectrum of deuterated ammonia prepared in Example 1 of the present invention. DETAILED DESCRIPTION
[0030] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.
[0031] The present invention is further described below in conjunction with specific examples, and the protection scope of the present invention is not limited by the following examples. The sources of the materials mainly involved in the examples are shown in Table 1 below, and the remaining materials not shown are conventional commercial products.
[0032] Table 1 Material source description
[0033] Serial number Material / Equipment Name Specifications / Models factory 1 Karl Fischer Titrator AKF-3N Shanghai Hegong Scientific Instrument Co., Ltd. 2 In situ mass spectrometer PIMS-M500 Dalian Institute of Chemical Physics, Chinese Academy of Sciences 3 heavy water >99％ Anhui Zesen Technology Co., Ltd. 4 Ammonium Nitrate >99.9％ Anhui Zesen Technology Co., Ltd. 5 Ammonium carbonate >99.9％ Anhui Zesen Technology Co., Ltd.
[0034] The performance tests involved in the following embodiments and comparative examples of this application include:
[0035] a. Moisture content test
[0036] After deuterated ammonia is cooled and liquefied, it is passed into dry ethylene glycol and heated to volatilize the deuterated ammonia. The water content in the ethylene glycol is then measured using a Karl Fischer moisture meter to calculate the water content in the deuterated ammonia.
[0037] b. Deuterated ammonia abundance test
[0038] The abundance of deuterated ammonia was obtained by monitoring the peak areas of fragments with m / z of 17, 18, 19, and 20 using an in-situ mass spectrometer.
[0039] The following are examples of the present application.
[0040] Example 1
[0041] See attached Figure 1 This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0042] Add 80 g of ammonium nitrate to 400 g of heavy water, mix, adjust the pH to 5, stir at 25 ° C for 8 hours, evaporate the mixture at normal pressure 110 ° C to obtain semi-deuterated ammonium nitrate crystals, and condense and recover semi-heavy water to complete one exchange.
[0043] The obtained semi-deuterated ammonium nitrate crystals were exchanged three times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.7%, indicating that the exchange reached equilibrium.
[0044] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0.02 MPa and a temperature of 80° C. and dried for 24 hours.
[0045] The deuterated ammonium nitrate crystals after primary drying were roasted at 150°C for 2 hours, and the gas obtained by roasting was dried twice in a magnesium nitride drying column and a 3A molecular sieve drying column. A pre-evacuated steel cylinder was used to absorb the dried gas, and the steel cylinder was immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0046] A total of 19.5 g of deuterated liquid ammonia was collected, with a yield of 97.5%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <200 ppm, and the degree of deuteration was >99.5%. Figure 2 It can be seen that the deuterated ammonia product prepared by this method has high purity, and the mass spectrum characteristics are consistent with deuterated ammonia, indicating that this method can prepare high-purity deuterated ammonia.
[0047] Example 2
[0048] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0049] Add 80 g of ammonium carbonate to 800 g of heavy water, mix, adjust the pH value to 9, stir at 25 ° C for 8 hours, evaporate the mixed solution at room temperature and pressure to obtain semi-deuterated ammonium carbonate crystals, and condense and recover semi-heavy water to complete one exchange.
[0050] The obtained semi-deuterated ammonium carbonate crystals were exchanged three times according to the above operation. The D abundance of the evaporated liquid after the last exchange was detected to be 99.8%, indicating that the exchange reached equilibrium.
[0051] The obtained deuterated ammonium carbonate crystals were placed in a vacuum drying oven at an absolute pressure of 0.02 MPa and a temperature of 80° C. and dried for 24 h.
[0052] The deuterated ammonium carbonate crystals after primary drying are roasted at 200°C for 2 hours, and the gas obtained by roasting is dried twice in a soda lime drying column and a 3A molecular sieve drying column. A pre-evacuated steel cylinder is used to absorb the dried gas, and the steel cylinder is immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0053] A total of 27.5 g of deuterated liquid ammonia was collected, with a yield of 82.5%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <300 ppm, and the degree of deuteration was >99.8%.
[0054] Example 3
[0055] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0056] Add 100 g of ammonium phosphate to 400 g of heavy water, mix, adjust the pH to 5, and stir at 0°C for 8 hours to obtain semi-deuterated ammonium nitrate crystals. At the same time, condense and recover semi-heavy water to complete one exchange.
[0057] The obtained semi-deuterated ammonium nitrate crystals were exchanged 4 times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.8%, indicating that the exchange reached equilibrium.
[0058] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0 MPa and a temperature of 20° C. and dried for 24 hours.
[0059] The deuterated ammonium nitrate crystals after primary drying are roasted at 350°C for 5 hours, and the gas obtained by roasting is dried twice in a potassium hydroxide drying column and an alumina drying column. A pre-evacuated steel cylinder is used to absorb the dried gas, and the steel cylinder is immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0060] A total of 39.7 g of deuterated liquid ammonia was collected, with a yield of 98.6%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <250 ppm, and the degree of deuteration was >99.5%.
[0061] Example 4
[0062] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0063] Add 60 g of ammonium monohydrogen phosphate to 400 g of heavy water, mix, adjust the pH to 3, and stir at 40° C. for 8 h to obtain semi-deuterated ammonium nitrate crystals. At the same time, condense and recover semi-heavy water to complete one exchange.
[0064] The obtained semi-deuterated ammonium nitrate crystals were exchanged 5 times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.6%, indicating that the exchange reached equilibrium.
[0065] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0 MPa and a temperature of 20° C. and dried for 24 h.
[0066] The deuterated ammonium nitrate crystals after primary drying were roasted at 250°C for 3 hours, and the gas obtained by roasting was dried twice in a sodium hydroxide drying column and a 5A molecular sieve drying column. A pre-evacuated steel cylinder was used to absorb the dried gas, and the steel cylinder was immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0067] A total of 17.8 g of deuterated liquid ammonia was collected, with a yield of 99.7%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <300 ppm, and the degree of deuteration was >99.7%.
[0068] Example 5
[0069] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0070] Add 80 g of ammonium dihydrogen phosphate to 400 g of heavy water, mix, adjust the pH to 2, and stir at 0°C for 8 hours to obtain semi-deuterated ammonium nitrate crystals. At the same time, condense and recover semi-heavy water to complete one exchange.
[0071] The obtained semi-deuterated ammonium nitrate crystals were exchanged 5 times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.7%, indicating that the exchange reached equilibrium.
[0072] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0 MPa and a temperature of 20° C. and dried for 24 h.
[0073] The deuterated ammonium nitrate crystals after primary drying were roasted at 250°C for 3 hours, and the gas obtained by roasting was dried twice in a sodium carbonate drying column and a 13X molecular sieve drying column. A pre-evacuated steel cylinder was used to absorb the dried gas, and the steel cylinder was immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0074] A total of 13.6 g of deuterated liquid ammonia was collected, with a yield of 99.8%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <320 ppm, and the degree of deuteration was >99.8%.
[0075] Example 6
[0076] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0077] Add 80 g of ammonium oxalate to 400 g of heavy water, mix, adjust the pH to 7, and stir at 40° C. for 8 h to obtain semi-deuterated ammonium nitrate crystals. At the same time, condense and recover semi-heavy water to complete one exchange.
[0078] The obtained semi-deuterated ammonium nitrate crystals were exchanged 4 times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.8%, indicating that the exchange reached equilibrium.
[0079] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0.1 MPa and a temperature of 80° C. and dried for 24 hours.
[0080] The deuterated ammonium nitrate crystals after primary drying were roasted at 250°C for 3 hours, and the gas obtained by roasting was dried twice in a potassium carbonate drying column and a 3A molecular sieve drying column. A pre-evacuated steel cylinder was used to absorb the dried gas, and the steel cylinder was immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0081] A total of 23.3 g of deuterated liquid ammonia was collected, with a yield of 90.5%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <300 ppm, and the degree of deuteration was >99.4%.
[0082] Example 7
[0083] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0084] Add 40 g of ammonium citrate to 400 g of heavy water, mix, adjust the pH to 6, and stir at 40° C. for 8 h to obtain semi-deuterated ammonium nitrate crystals. At the same time, condense and recover semi-heavy water to complete one exchange.
[0085] The obtained semi-deuterated ammonium nitrate crystals were exchanged three times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.5%, indicating that the exchange reached equilibrium.
[0086] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0.06 MPa and a temperature of 60° C. and dried for 4 h.
[0087] The deuterated ammonium nitrate crystals after primary drying are roasted at 500°C for 5 hours, and the gas obtained by roasting is dried twice in a calcium oxide drying column and a 3A molecular sieve drying column. A pre-evacuated steel cylinder is used to absorb the dried gas, and the steel cylinder is immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0088] A total of 9.13 g of deuterated liquid ammonia was collected, with a yield of 92.5%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <270 ppm, and the degree of deuteration was >99.5%.
[0089] Example 8
[0090] This embodiment provides a method for preparing deuterated ammonia, comprising the following steps:
[0091] Add 80 g of ammonium nitrate to 400 g of heavy water, mix, adjust the pH to 5, and stir at 25°C for 8 hours to obtain semi-deuterated ammonium nitrate crystals. At the same time, condense and recover semi-heavy water to complete one exchange.
[0092] The obtained semi-deuterated ammonium nitrate crystals were exchanged three times according to the above operation to obtain deuterated ammonium nitrate crystals. The evaporated liquid after the last exchange was detected, and the D abundance was 99.3%, indicating that the exchange reached equilibrium.
[0093] The obtained deuterated ammonium nitrate crystals were placed in a vacuum drying oven at an absolute pressure of 0.02 MPa and a temperature of 80° C. and dried for 24 hours.
[0094] The deuterated ammonium nitrate crystals after primary drying were roasted at 150°C for 2 hours, and the gas obtained by roasting was dried twice in a sodium metal drying column and a 3A molecular sieve drying column. A pre-evacuated steel cylinder was used to absorb the dried gas, and the steel cylinder was immersed in an ice ethanol bath at -40°C to obtain deuterated liquid ammonia.
[0095] A total of 19.62 g of deuterated liquid ammonia was collected, with a yield of 98.1%. After testing, the water content of the deuterated liquid ammonia prepared in this example was <60 ppm, and the degree of deuteration was >99.8%.
[0096] The following is a comparative example of the present application.
[0097] Comparative Example 1
[0098] The difference from Example 1 is that the ammonium nitrate crystals obtained after the exchange are not dried once.
[0099] The evaporated liquid was measured and the D abundance was found to be 99.7%. The exchange reached equilibrium and deuterated ammonium nitrate was obtained.
[0100] A total of 20.2 g of deuterated liquid ammonia was collected, with a yield of 95.5%, a water content of 1.2%, and a deuteration degree of >99.5%.
[0101] Comparative Example 2
[0102] The difference from Example 1 is that the number of exchanges is 6 times in total.
[0103] The evaporated liquid was measured and the D abundance was found to be 99.7%. The exchange reached equilibrium and deuterated ammonium nitrate was obtained.
[0104] A total of 19.5 g of deuterated liquid ammonia was collected, with a yield of 96.1%, a water content of <200 ppm, and a deuteration degree of >99.5%.
[0105] Comparative Example 3
[0106] The difference from Example 1 is that the calcination temperature is 110°C.
[0107] The evaporated liquid was measured and the D abundance was found to be 99.7%. The exchange reached equilibrium and deuterated ammonium nitrate was obtained.
[0108] A total of 11.4 g of deuterated liquid ammonia was collected, with a yield of 57%, a water content of <200 ppm, and a deuteration degree of >99.5%.
[0109] Comparative Example 4
[0110] The difference from Example 1 is that the number of exchanges is 1
[0111] The evaporated liquid was measured and the D abundance was 76.1%. The exchange equilibrium was not reached and half-deuterated ammonium nitrate was obtained. Drying and calcination were continued.
[0112] A total of 17.44 g of deuterated liquid ammonia was collected, with a yield of 87.2%, a water content of <200 ppm, and a deuteration degree of 82.1%.
[0113] Comparative Example 5
[0114] The difference from Example 1 is that the calcination temperature is 800°C.
[0115] The evaporated liquid was measured and the D abundance was found to be 99.7%. The exchange reached equilibrium and deuterated ammonium nitrate was obtained.
[0116] A total of 11.6 g of deuterated liquid ammonia was collected, with a yield of 99.9%, a water content of <160 ppm, and a deuteration degree of >99.6%.
[0117] Based on the test results of Examples 1 to 8 and Comparative Examples 1 to 4, it can be obtained that:
[0118] (1) In combination with Example 1 and Comparative Example 1, it can be seen that if the deuterated ammonium nitrate crystals are not dried once, the water content in the finished deuterated ammonia will increase significantly, resulting in a decrease in the purity of the deuterated ammonia, which is not conducive to the application of deuterated ammonia in high-purity application fields (such as chemical vapor deposition and electronic gases).
[0119] (2) Combining Example 1 with Comparative Examples 2 and 4, it can be seen that increasing the number of exchanges does not further increase the abundance. On the contrary, increasing the number of operations easily causes a large amount of product loss during the operation, resulting in a decrease in yield; while reducing the number of exchanges will lead to a decrease in the abundance of deuterated ammonia.
[0120] (3) Combining Example 1 with Comparative Examples 3 and 5, it can be seen that lowering the roasting temperature will result in the inability of deuterated ammonium nitrate crystals to be completely decomposed, which will seriously reduce the yield. Deuterated ammonium nitrate crystals can be completely decomposed at a specific temperature. Raising the roasting temperature will not lead to a significant increase in the yield, but will increase the equipment investment cost and energy consumption.
[0121] In summary, under the preparation conditions of the present invention, through multiple exchanges and evaporation to recover semi-heavy water, secondary drying and purification of the product and other steps, not only can a high-purity, high-deuterated ammonia product be obtained, the generation of by-products or harmful substances can be reduced, but also the maximum utilization of resources can be achieved, energy consumption can be saved, and production costs can be reduced, thereby significantly improving the economic benefits of the overall process.
[0122] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for preparing deuterated ammonia, characterized in that: The method comprises: The decomposable ammonium salt is exchanged multiple times in heavy water to obtain a deuterated ammonium salt; the deuterated ammonium salt is dried once, roasted, and dried twice to obtain deuterated ammonia; The exchange process comprises: mixing the decomposable ammonium salt and heavy water, stirring, evaporating, obtaining the semi-deuterated ammonium salt, and condensing and recovering the semi-heavy water to complete one exchange.
2. The preparation method according to claim 1, characterized in that The decomposable ammonium salt is selected from one of ammonium nitrate, ammonium carbonate, ammonium chloride, ammonium phosphate, ammonium monohydrogen phosphate, ammonium dihydrogen phosphate, ammonium oxalate or ammonium citrate.
3. The preparation method according to claim 1, characterized in that: The mass ratio of the decomposable ammonium salt to the heavy water is 1:(4-10).
4. The preparation method according to claim 1, characterized in that: During the exchange process, after mixing, the pH value of the solution is 2-9.
5. The preparation method according to claim 1, characterized in that: In the exchange process, the exchange temperature is 0 to 40° C., and the exchange times are 1 to 5 times.
6. The preparation method according to claim 1, characterized in that: The primary drying is performed at a temperature of 20 to 80° C., for a time of 4 to 24 hours, and at an absolute pressure of 0 to 0.1 MPa.
7. The preparation method according to claim 1, characterized in that: The calcination temperature is 120-500° C. and the calcination time is 2-5 hours.
8. The preparation method according to claim 1, characterized in that: The secondary drying includes a first stage drying and a second stage drying; the first stage drying uses an alkaline desiccant, and the second stage drying uses a neutral desiccant.
9. The preparation method according to claim 8, characterized in that: The alkaline desiccant is selected from one or more of magnesium nitride, soda lime, potassium hydroxide, sodium hydroxide, sodium carbonate, potassium carbonate, calcium oxide or sodium.
10. The preparation method according to claim 8, characterized in that: The neutral desiccant is selected from one or more of alumina, 3A molecular sieve, 5A molecular sieve or 13X molecular sieve.