Method for preparing deuterated sulfuric acid

Abstract

The invention relates to the technical field of deuterated sulfuric acid, in particular to a method for preparing deuterated sulfuric acid, which comprises the following steps: S1, heating pyrosulfuric acid to decompose the pyrosulfuric acid into sulfur trioxide and sulfuric acid; s2, collecting and curing sulfur trioxide; s3, the cured sulfur trioxide is refined; and S4, slowly heating the refined sulfur trioxide into sulfur trioxide gas, and introducing the sulfur trioxide gas into the heavy water to react to obtain the deuterated sulfuric acid. The method disclosed by the invention is simple to operate, the sulfur trioxide gas is introduced into the heavy water to react to obtain the deuterated sulfuric acid, and the operation is simple.

Description

Technical Field

[0001] The present invention relates to the technical field of deuterated sulfuric acid, and particularly relates to a method for preparing deuterated sulfuric acid. Background Art

[0002] As a new deuterated reagent, deuterated sulfuric acid has some special chemical and physical properties. In the fields of chemical synthesis and drug research and development, it can be used as a deuterium-labeled compound. In nuclear magnetic resonance analysis, deuterated sulfuric acid can be used to adjust the pH value to ensure that the sample is in a suitable chemical environment. At present, its main preparation method is to slowly drip heavy water into concentrated sulfuric acid in an inert environment and repeatedly carry out deuterium-hydrogen exchange to obtain it. It is necessary to add fresh heavy water for more than 5 exchanges. During the exchange process, the temperature and the dropping rate need to be strictly controlled to prevent the danger caused by too violent reaction. This process has cumbersome operations, many exchange times, large consumption of heavy water, and serious waste of raw materials. Summary of the Invention

[0003] The purpose of the present invention is to provide a method for preparing deuterated sulfuric acid, so as to solve the technical problems of cumbersome operations, many exchange times, large consumption of heavy water, and serious waste of raw materials in the prior art.

[0004] The present invention discloses a method for preparing deuterated sulfuric acid, which includes the following steps:

[0005] S1. Heat pyrosulfuric acid to decompose it into sulfur trioxide and sulfuric acid;

[0006] S2. Collect and solidify sulfur trioxide;

[0007] S3. Refine the solidified sulfur trioxide;

[0008] S4. Heat the refined sulfur trioxide into sulfur trioxide gas, and let the sulfur trioxide gas pass into heavy water to react to obtain deuterated sulfuric acid.

[0009] The reaction that occurs is: SO3 + D2O → D2SO4.

[0010] Further, in the step S1, pyrosulfuric acid is decomposed in a water bath.

[0011] Further, the temperature of the water bath is 50 - 55 °C.

[0012] Further, in the step S2, liquid nitrogen is used to solidify sulfur trioxide.

[0013] Further, in the step S3, the sulfur trioxide is refined by distillation.

[0014] Further, the distillation refinement is negative pressure distillation refinement.

[0015] Further, the negative pressure distillation refinement is to heat and solidify sulfur trioxide, and then collect and solidify sulfur trioxide.

[0016] Further, the pressure of the negative pressure distillation refinement is at least -0.1 Mpa.

[0017] Further, the steps of the negative pressure distillation refinement are repeated more than twice.

[0018] Further, the sulfuric acid is recycled.

[0019] Further, the heavy water is heavy water with a concentration greater than 99.80 atom% D.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] 1. Using pyrosulfuric acid which is easily decomposed into sulfuric acid and sulfur trioxide by heating, and sulfur trioxide reacts with heavy water to form deuterated sulfuric acid;

[0022] 2. Obtaining refined sulfur trioxide by sufficient distillation, effectively avoiding hydrogen-deuterium exchange and improving the deuteration rate;

[0023] 3. The method of the present invention is simple to operate. Passing sulfur trioxide gas into heavy water to react to obtain deuterated sulfuric acid, the operation is simple;

[0024] 4. By heating pyrosulfuric acid, sulfur trioxide can be obtained, and its waste liquid is sulfuric acid, which can be recycled. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, so it should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0026] Figure 1 It is a flowchart of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments.

[0028] Example 1

[0029] In this example, a method for preparing deuterated sulfuric acid is disclosed. As Figure 1 shown, it includes the following steps:

[0030] Step 1: Add 300 g of pyrosulfuric acid to a reaction flask, connect the absorption device, evacuate the system, introduce nitrogen, and indirectly heat the reaction flask with water at 50 - 55 °C to generate sulfur trioxide gas, which enters the receiving flask.

[0031] Step 2: Place the sulfur trioxide receiving flask from Step 1 into liquid nitrogen to solidify sulfur trioxide.

[0032] Step 3: Transfer the solidified sulfur trioxide to a refining device, evacuate the system, heat sulfur trioxide, place the receiving flask at the receiving end into liquid nitrogen to solidify sulfur trioxide again, and repeat this process more than twice.

[0033] Step 4: Remove the refined sulfur trioxide, heat the refined sulfur trioxide to generate sulfur trioxide gas, and pass the sulfur trioxide gas into 33 g of 99.80 atom% D heavy water to react with the heavy water to form deuterated sulfuric acid.

[0034] Step 5: After the reaction ends, 140 g of deuterated sulfuric acid is obtained, with a yield of 85%.

[0035] Step 6: For the deuteration rate of deuterated sulfuric acid, react a metal with deuterated sulfuric acid to generate deuterium gas, analyze the deuterium concentration using gas chromatography, and measure that the deuteration rate ≥ 99.0%.

[0036] Step 7: According to the detection of (GB / T 625 Chemical Reagent Sulfuric Acid), the purity ≥ 98%.

[0037] Example 2

[0038] A method for preparing deuterated sulfuric acid is disclosed in this example, as Figure 1 shown, including the following steps:

[0039] Step 1: Add 300 g of pyrosulfuric acid to a reaction flask, connect the absorption device, evacuate the system, introduce nitrogen, and indirectly heat the reaction flask with water at 50 - 55 °C to generate sulfur trioxide gas, which enters the receiving flask.

[0040] Step 2: Place the sulfur trioxide receiving flask from Step 1 into liquid nitrogen to solidify sulfur trioxide.

[0041] Step 3: Transfer the solidified sulfur trioxide to a refining device, evacuate the system, heat sulfur trioxide, place the receiving flask at the receiving end into liquid nitrogen to solidify sulfur trioxide again, and repeat this process more than twice.

[0042] Step 4: Remove the refined sulfur trioxide, heat the refined sulfur trioxide to generate sulfur trioxide gas, and pass the sulfur trioxide gas into 33 g of 99.90 atom% D heavy water to react with the heavy water to form deuterated sulfuric acid.

[0043] Step 5: After the reaction ends, 150 g of deuterated sulfuric acid is obtained, with a yield of 91%.

[0044] Step 6: Deuterium substitution rate of deuterated sulfuric acid. React a metal with deuterated sulfuric acid to generate deuterium gas, analyze the deuterium concentration by gas chromatography, and the measured deuterium substitution rate is ≥99.0%.

[0045] Step 7: Detect according to (GB / T 625 Chemical Reagent Sulfuric Acid), and the purity is ≥98%.

[0046] Comparative Example 1

[0047] Prepare deuterated sulfuric acid by the control exchange method

[0048] Add 70 g of heavy water to a 500 mL two-necked flask equipped with a reflux condenser. While stirring, add 160 g of concentrated sulfuric acid dropwise. The addition is completed in about 15 minutes. Heat the mixture to 100 °C and react for three hours. After the reaction is completed, change the reaction device to a distillation device to remove the dilute heavy water inside and retain the kettle liquid. In this way, repeat five times to obtain 140 g of deuterated sulfuric acid, with a yield of 87.5%. The measured deuterium substitution rate is ≥99.0%, and the purity is ≥98%. A total of 350 g of heavy water is used.

[0049] Comparative Example 2

[0050] Step 1: Add 300 g of pyrosulfuric acid to the reaction flask, connect the absorption device, evacuate the system, introduce nitrogen, and indirectly heat the reaction flask with water at 50 - 55 °C to generate sulfur trioxide gas, which enters the receiving flask.

[0051] Step 2: Place the sulfur trioxide receiving flask in step 1 into liquid nitrogen to solidify sulfur trioxide.

[0052] Step 3: Transfer the solidified sulfur trioxide to the refining device, evacuate the system, heat sulfur trioxide, place the receiving flask at the receiving end in liquid nitrogen, and solidify sulfur trioxide again. Repeat this process more than twice.

[0053] Step 4: Remove the refined sulfur trioxide, heat the refined sulfur trioxide to generate sulfur trioxide gas, and introduce the sulfur trioxide gas into 33 g of heavy water with 99.70 atom% D to react with the heavy water to generate deuterated sulfuric acid.

[0054] Step 5: After the reaction is completed, 135 g of deuterated sulfuric acid is obtained, with a yield of 82%.

[0055] Step 6: For the deuterium substitution rate of deuterated sulfuric acid, react a metal with deuterated sulfuric acid to generate deuterium gas, analyze the deuterium concentration by gas chromatography, and the measured deuterium substitution rate is <95.0%.

[0056] Step 7: Detect according to (GB / T 625 Chemical Reagent Sulfuric Acid), and the purity is ≥98%.

[0057] Comparative Example 3

[0058] Step 1: Add 300 g of pyrosulfuric acid to a reaction flask, connect the absorption device, evacuate the system, introduce nitrogen, and indirectly heat the reaction flask with water at 50 - 55 °C to generate sulfur trioxide gas, which enters the receiving flask.

[0059] Step 2: Place the sulfur trioxide receiving flask from Step 1 into liquid nitrogen to solidify sulfur trioxide.

[0060] Step 3: Heat the sulfur trioxide in Step 2 to generate sulfur trioxide gas, and pass the sulfur trioxide gas into 33 g of 99.80 atom% D heavy water to react with the heavy water to form deuterated sulfuric acid.

[0061] Step 4: After the reaction ends, 130 g of deuterated sulfuric acid is obtained, with a yield of 79%.

[0062] Step 5: For the deuteration rate of deuterated sulfuric acid, react a metal with deuterated sulfuric acid to generate deuterium gas, and analyze the deuterium concentration using gas chromatography. The measured deuteration rate is <98.0%.

[0063] Step 6: According to the detection of (GB / T 625 Chemical Reagent Sulfuric Acid), the purity is <95%.

[0064] It can be seen from Examples 1 - 2 and Comparative Example 1 that compared with the prior art, the technical solution of the present invention can save a large amount of heavy water.

[0065] In Comparative Example 2, due to the insufficient heavy water concentration, the deuteration rate is <95.0% and the yield of deuterated sulfuric acid is 82%, which is significantly lower than the effect that can be achieved by the technical solution of the present invention.

[0066] In Comparative Example 3, due to the lack of a sulfur trioxide purification step, the yield of deuterated sulfuric acid is 79% and the purity of sulfuric acid is <95%, which is significantly lower than the effect that can be achieved by the technical solution of the present invention.

[0067] The above are the implementation manners listed in this embodiment, but this embodiment is not limited to the above optional implementation manners. Those skilled in the art can obtain many other implementation manners by arbitrarily combining the above manners. Anyone can obtain other various forms of implementation manners under the inspiration of this embodiment. The above specific implementation manners should not be construed as limiting the protection scope of this embodiment. The protection scope of this embodiment should be defined by the claims, and the description can be used to interpret the claims.

Claims

1. A method for preparing deuterated sulfuric acid, characterized in that: It includes the following steps: S1. Heat pyrosulfuric acid to decompose it into sulfur trioxide and sulfuric acid; S2. Collect and solidify sulfur trioxide; S3. Refine the solidified sulfur trioxide; S4. Heat the refined sulfur trioxide into sulfur trioxide gas, and let the sulfur trioxide gas react with heavy water to obtain deuterated sulfuric acid.

2. The method for preparing deuterated sulfuric acid according to claim 1, wherein: In step S1, pyrosulfuric acid is decomposed through a water bath.

3. A method for preparing deuterated sulfuric acid according to claim 2, characterized in that: The temperature of the water bath is 50 - 55 °C.

4. A method for preparing deuterated sulfuric acid according to claim 1, characterized in that: In step S2, liquid nitrogen is used to solidify sulfur trioxide.

5. A method for preparing deuterated sulfuric acid according to claim 1, characterized in that: In step S3, the sulfur trioxide is refined by distillation.

6. A method for preparing deuterated sulfuric acid according to claim 5, characterized in that: The distillation refinement is vacuum distillation refinement.

7. A method for preparing deuterated sulfuric acid according to claim 6, characterized in that: The vacuum distillation refinement is to heat the solidified sulfur trioxide, and then collect and solidify sulfur trioxide again.

8. A method for preparing deuterated sulfuric acid according to claim 6, characterized in that: The step of vacuum distillation refinement is repeated more than twice.

9. A method for preparing deuterated sulfuric acid according to claim 1, characterized in that: The sulfuric acid is recycled.

10. A method for preparing deuterated sulfuric acid according to claim 1, characterized in that: The heavy water is heavy water with a concentration greater than 99.80 atom%D.

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