A production process for high-purity sodium azide

Abstract

The present invention discloses a production process of high-purity sodium azide. By mixing the generated material containing ethyl nitrite with an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide and pyridine for reaction, and then through purification treatment, high-purity sodium azide is prepared. The sodium azide prepared by the method of the present invention has high purity, low by-products and high product yield; moreover, the reaction does not require a high-pressure environment, is convenient to control, easy to operate, has low danger, reduces costs and improves economic benefits.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium azide production, and particularly relates to a production process of high-purity sodium azide. Background Art

[0002] Sodium azide is a fine chemical product and can be widely used in the fields of medicine, pesticides, automobiles, military, biology, etc. In China, sodium azide is mainly used in the pharmaceutical industry, mainly for synthesizing cefazolin, cefoperazone, losartan, valsartan, etc., and is an important intermediate for cephalosporin antibiotics and valsartan anti-hypertensive drugs. With the rapid development of the automobile manufacturing industry in China, the consumption of sodium azide as an inflator for automobile airbags has been increasing year by year. Sodium azide can also be used for the preparation of hydrazoic acid, lead azide, high-purity sodium, etc., and is applied in organic synthesis. The main methods for synthesizing sodium azide include the sodium method, the hydrazine hydrate method, the urea method, the nitroguanidine method, the liquid phase method, etc. At present, most domestic and foreign manufacturers generally adopt the synthesis process of reacting ethyl nitrite gas with an ethanol solution containing hydrazine hydrate and sodium hydroxide. This process has simple reactions, high yields, good product purity, simple equipment, and small investment, and is suitable for large-scale industrial production. However, at present, the reaction period of the ethyl nitrite method is long, the control of gas-liquid reaction is difficult, the utilization rate of ethyl nitrite is low; and the yield of sodium azide in the reaction process is relatively low. Summary of the Invention

[0003] Therefore, the present invention provides a production process of high-purity sodium azide, and its steps are as follows:

[0004] (1) Prepare an aqueous solution of sulfuric acid and a mixture of ethanol and sodium nitrite; place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed with -5°C ethanol cold liquid as a coolant, and the material collection bottle is placed in an ice-water bath; the conical flask is placed in a water bath at 35±2°C for constant temperature and heat preservation. Then, the aqueous solution of sulfuric acid is added dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 - 120 minutes. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35±2°C for more than 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material;

[0005] (2) Under the condition of an ice-water bath, successively add an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine to the material collection bottle. After the addition is completed, magnetically stir for 20 - 30 minutes under the condition of an ice-water bath. Then, seal the material collection bottle and place it in a water bath at 30±3°C for static settlement for 12 - 16 hours to obtain a mixture containing crude sodium azide;

[0006] (3) Open the material collection bottle, and dehydrate the mixture containing the crude sodium azide under reduced pressure at 70 - 75 °C to precipitate crystals. Then, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0007] Furthermore, in the aqueous solution of sulfuric acid, the mass percentage content of the solute is 50% - 55%, and the mixture of ethanol and sodium nitrite is ethanol and sodium nitrite with a mass ratio of ethanol:sodium nitrite = 1:1.2 - 1.5.

[0008] Furthermore, the mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise to the mixture of ethanol and sodium nitrite is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1 - 1.2:1.

[0009] Furthermore, in the aqueous solution of sodium hydroxide, the mass percentage content of the solute is 30%, and the solvent is water; the mass ratio of the added aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:tetrabutylammonium hydroxide:pyridine = 10:12 - 16:7 - 9:0.6 - 1:0.3 - 0.8.

[0010] Furthermore, replace the tetrabutylammonium hydroxide with an additive. The preparation method of the additive is as follows: Prepare an aqueous solution of p-toluenesulfonic acid and an ethanol solution of tributylamine; keep the ethanol solution of tributylamine in a water bath at a constant temperature of 6 ± 3 °C for heat preservation, then stir the ethanol solution of tributylamine, and add the aqueous solution of p-toluenesulfonic acid to the solution under stirring. After the addition is completed, keep it at 6 ± 3 °C for more than 100 min, and then perform rotary evaporation under reduced pressure at 80 °C to remove ethanol and water. Add the obtained product to an aqueous solution of polyethylene glycol 1000 to obtain the additive.

[0011] Furthermore, in the aqueous solution of p-toluenesulfonic acid, the concentration of p-toluenesulfonic acid is 16 - 20 g / 100 mL, and the solvent is water; in the ethanol solution of tributylamine, the concentration of tributylamine is 3 - 5 g / 100 mL, and the solvent is ethanol; the volume ratio of the aqueous solution of p-toluenesulfonic acid added to the ethanol solution of tributylamine is ethanol solution of tributylamine:aqueous solution of p-toluenesulfonic acid = 10:3 - 4.

[0012] Furthermore, in the aqueous solution of polyethylene glycol 1000, the mass percentage content of polyethylene glycol 1000 is 10%, and the amount ratio of the product added to the aqueous solution of polyethylene glycol 1000 is product:aqueous solution of polyethylene glycol 1000 = 1 g:10 mL.

[0013] Furthermore, the volume ratio of the added additive to the mass of the product material is product material:additive = 10 g:1 - 2 mL.

[0014] The beneficial effects of the present invention are as follows: The sodium azide prepared by the method of the present invention has high purity, low by-products, and a relatively high product yield; moreover, the reaction does not require a high-pressure environment, is convenient to control, easy to operate, has low danger, reduces costs, and improves economic benefits. Specific Embodiments

[0015] The present invention will be further described below in conjunction with embodiments.

[0016] Example 1

[0017] A production process of high-purity sodium azide, the steps of which are as follows:

[0018] (1) Prepare an aqueous solution of sulfuric acid. In the aqueous solution of sulfuric acid, the mass percentage content of the solute is 50%. Prepare a mixture of ethanol and sodium nitrite. The mixture of ethanol and sodium nitrite is formed by mixing ethanol and sodium nitrite in a mass ratio of ethanol:sodium nitrite = 1:1.2; the mixture of ethanol and sodium nitrite is placed in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed with -5°C ethanol cold liquid as a coolant. The material collection bottle is placed in an ice-water bath; the conical flask is placed in a water bath at 35±2°C for constant temperature and heat preservation. Then, the aqueous solution of sulfuric acid is added dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed in 100 minutes. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise to the mixture of ethanol and sodium nitrite is 1.2:1; after the addition is completed, the conical flask continues to be kept at a constant temperature of 35±2°C for 20 minutes. The product passes through the condenser for condensation and reflux and then enters the material collection bottle to obtain the product material;

[0019] (2) Under the condition of an ice-water bath, an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine are sequentially added to the material collection bottle. In the aqueous solution of sodium hydroxide, the mass percentage content of the solute is 30%, and the solvent is water; the mass ratio of the product material, the aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine added is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:tetrabutylammonium hydroxide: pyridine = 10:12:7:0.6:0.3; after the addition is completed, magnetic stirring is carried out for 20 minutes under the condition of an ice-water bath, and then the material collection bottle is sealed and placed in a water bath at 30±3°C for static settlement for 14 hours to obtain a mixture containing crude sodium azide;

[0020] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70°C, precipitate crystals, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0021] Example 2

[0022] A production process of high-purity sodium azide, the steps of which are as follows:

[0023] (1) Prepare an aqueous solution of sulfuric acid. In the aqueous solution of sulfuric acid, the mass percentage content of the solute is 50%. Prepare a mixture of ethanol and sodium nitrite, which is a mixture of ethanol and sodium nitrite mixed in a mass ratio of ethanol:sodium nitrite = 1:1.3. Place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed with -5°C ethanol cold liquid as a coolant. The material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, dropwise add the aqueous solution of sulfuric acid to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 minutes. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1.2:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material.

[0024] (2) Under the condition of an ice-water bath, successively add an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine to the material collection bottle. In the aqueous solution of sodium hydroxide, the mass percentage content of the solute is 30%, and the solvent is water. The mass ratio of the product material, the aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine added is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:tetrabutylammonium hydroxide: pyridine = 10:14:8:0.8:0.5. After the feeding is completed, magnetically stir for 20 minutes under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 hours to obtain a mixture containing crude sodium azide.

[0025] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70°C, precipitate crystals, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0026] Example 3

[0027] A production process of high-purity sodium azide, the steps of which are as follows:

[0028] (1) Prepare an aqueous solution of sulfuric acid with a mass percentage of the solute of 55%. Prepare a mixture of ethanol and sodium nitrite, which is a mixture of ethanol and sodium nitrite mixed in a mass ratio of ethanol:sodium nitrite = 1:1.4. Place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed through with ethanol coolant at -5°C as the coolant, and the material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, add the aqueous solution of sulfuric acid dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed in 100 minutes. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material.

[0029] (2) Under the condition of an ice-water bath, add an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine to the material collection bottle in sequence. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30%, and the solvent is water. The mass ratio of the product material, the aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:tetrabutylammonium hydroxide:pyridine = 10:14:8:0.8:0.6. After the addition is completed, stir magnetically for 20 minutes under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 hours to obtain a mixture containing crude sodium azide.

[0030] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70°C, precipitate crystals, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0031] Example 4

[0032] A production process of high-purity sodium azide, the steps of which are as follows:

[0033] (1) Prepare an aqueous solution of sulfuric acid, in which the mass percentage of the solute is 55%. Prepare a mixture of ethanol and sodium nitrite, which is a mixture of ethanol and sodium nitrite mixed in a mass ratio of ethanol:sodium nitrite = 1:1.5. Place the mixture of ethanol and sodium nitrite in a conical flask, and connect the conical flask to a material collection bottle through a condenser. The condenser is passed through with ethanol coolant at -5°C as the coolant, and the material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, dropwise add the aqueous solution of sulfuric acid to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 minutes. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material;

[0034] (2) Under the condition of an ice-water bath, successively add an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine to the material collection bottle. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30%, and the solvent is water. The mass ratio of the product material, the aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine added is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:tetrabutylammonium hydroxide:pyridine = 10:16:9:1:0.8. After the addition is completed, magnetically stir for 20 minutes under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 hours to obtain a mixture containing crude sodium azide;

[0035] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70°C, precipitate crystals, separate the solid and liquid, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0036] Example 5

[0037] A production process of high-purity sodium azide, the steps of which are as follows:

[0038] (1) Prepare an aqueous solution of sulfuric acid. In the aqueous solution of sulfuric acid, the mass percentage of the solute is 55%. Prepare a mixture of ethanol and sodium nitrite, which is a mixture of ethanol and sodium nitrite mixed in a mass ratio of ethanol:sodium nitrite = 1:1.4. Place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed with -5°C ethanol cold liquid as a coolant, and the material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, add dropwise the aqueous solution of sulfuric acid to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 min. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 min. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material;

[0039] (2) Under the condition of an ice-water bath, add an aqueous solution of sodium hydroxide, hydrazine hydrate, an additive, and pyridine to the material collection bottle in sequence. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30%, and the solvent is water. The dosage ratio of the aqueous solution of sodium hydroxide, hydrazine hydrate, the additive, and pyridine is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:additive:pyridine = 10 g:14 g:8 g:1 mL:0.6 g. After the feeding is completed, stir magnetically for 20 min under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 h to obtain a mixture containing crude sodium azide. The preparation method of the additive is as follows: Prepare an aqueous solution of p-toluenesulfonic acid and an ethanol solution of tributylamine. In the aqueous solution of p-toluenesulfonic acid, the concentration of p-toluenesulfonic acid is 16 g / 100 mL, and the solvent is water. In the ethanol solution of tributylamine, the concentration of tributylamine is 3 g / 100 mL, and the solvent is ethanol. Keep the ethanol solution of tributylamine in a water bath at a constant temperature of 6 ± 3°C for heat preservation, then stir the ethanol solution of tributylamine, and add dropwise the aqueous solution of p-toluenesulfonic acid to the solution under stirring. The volume ratio of the ethanol solution of tributylamine to the aqueous solution of p-toluenesulfonic acid added dropwise is ethanol solution of tributylamine:aqueous solution of p-toluenesulfonic acid = 10:3. After the feeding is completed, keep it at 6 ± 3°C for 100 min, then remove ethanol and water by rotary evaporation under reduced pressure at 80°C. The obtained product is added to an aqueous solution of polyethylene glycol 1000. In the aqueous solution of polyethylene glycol 1000, the mass percentage of polyethylene glycol 1000 is 10%. The dosage ratio of the product to the aqueous solution of polyethylene glycol 1000 added is product:aqueous solution of polyethylene glycol 1000 = 1 g:10 mL. Obtain the additive;

[0040] (3) Open the material collection bottle, dehydrate the mixture containing the crude sodium azide under reduced pressure at 70 °C, precipitate crystals, separate the solid from the liquid, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0041] Example 6

[0042] A production process for high-purity sodium azide, the steps of which are as follows:

[0043] (1) Prepare an aqueous solution of sulfuric acid, in which the mass percentage content of the solute is 55%. Prepare a mixture of ethanol and sodium nitrite, which is a mixture of ethanol and sodium nitrite in a mass ratio of ethanol:sodium nitrite = 1:1.4. Place the mixture of ethanol and sodium nitrite in a conical flask, connect the conical flask to a material collection bottle through a condenser, and pass -5 °C ethanol cold liquid as a coolant through the condenser. Place the material collection bottle in an ice-water bath. Place the conical flask in a water bath at 35 ± 2 °C for constant temperature and insulation. Then, add dropwise the aqueous solution of sulfuric acid to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 min. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, continue to keep the conical flask at a constant temperature of 35 ± 2 °C for 20 min. The product enters the material collection bottle after being condensed and refluxed through the condenser to obtain the product material;

[0044] (2) Under the condition of an ice-water bath, an aqueous solution of sodium hydroxide, hydrazine hydrate, an additive, and pyridine are sequentially added to the material collection bottle. In the aqueous solution of sodium hydroxide, the mass percentage content of the solute is 30%, and the solvent is water; the amount ratio of the added aqueous solution of sodium hydroxide, hydrazine hydrate, additive, and pyridine is product material: aqueous solution of sodium hydroxide: hydrazine hydrate: additive: pyridine = 10 g: 14 g: 8 g: 2 mL: 0.6 g; after the feeding is completed, magnetic stirring is carried out for 20 min under the ice-water bath condition, then the material collection bottle is sealed and placed in a water bath at 30 ± 3 °C for static settlement for 14 h to obtain a mixture containing crude sodium azide; wherein the preparation method of the additive is as follows: prepare an aqueous solution of p-toluenesulfonic acid and an ethanol solution of tributylamine; in the aqueous solution of p-toluenesulfonic acid, the concentration of p-toluenesulfonic acid is 18 g / 100 mL, and the solvent is water; in the ethanol solution of tributylamine, the concentration of tributylamine is 4 g / 100 mL, and the solvent is ethanol; keep the ethanol solution of tributylamine in a water bath at a constant temperature of 6 ± 3 °C for heat preservation, then stir the ethanol solution of tributylamine, and add the aqueous solution of p-toluenesulfonic acid to the solution under stirring. The volume ratio of the aqueous solution of p-toluenesulfonic acid added to the ethanol solution of tributylamine is ethanol solution of tributylamine: aqueous solution of p-toluenesulfonic acid = 10:3; after the feeding is completed, keep it at 6 ± 3 °C for heat preservation for 100 min, then carry out rotary evaporation under reduced pressure at 80 °C to remove ethanol and water, and add the obtained product to an aqueous solution of polyethylene glycol 1000. In the aqueous solution of polyethylene glycol 1000, the mass percentage content of polyethylene glycol 1000 is 10%. The amount ratio of the product added to the aqueous solution of polyethylene glycol 1000 is product: aqueous solution of polyethylene glycol 1000 = 1 g: 10 mL; obtain the additive;

[0045] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70 °C, precipitate crystals, carry out solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

[0046] Comparative Example 1

[0047] A production process of sodium azide, the steps of which are as follows:

[0048] (1) Prepare an aqueous solution of sulfuric acid. In the aqueous solution of sulfuric acid, the mass percentage of the solute is 55%. Prepare a mixture of ethanol and sodium nitrite. The mixture of ethanol and sodium nitrite is formed by mixing ethanol and sodium nitrite in a mass ratio of ethanol:sodium nitrite = 1:1.4. Place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed through with -5°C ethanol cold liquid as a coolant. The material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, add the aqueous solution of sulfuric acid dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 min. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 min. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material;

[0049] (2) Under the condition of an ice-water bath, add an aqueous solution of sodium hydroxide and hydrazine hydrate to the material collection bottle in sequence. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30%, and the solvent is water. The mass ratio of the product material, the aqueous solution of sodium hydroxide, and hydrazine hydrate added is product material:aqueous solution of sodium hydroxide:hydrazine hydrate = 10:14:8. After the addition is completed, stir magnetically for 20 min under the condition of an ice-water bath. Then, seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 h to obtain a mixture containing crude sodium azide;

[0050] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70°C, precipitate crystals, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide product of this comparative example.

[0051] Comparative Example 2

[0052] A production process of sodium azide, the steps of which are as follows:

[0053] (1) Prepare an aqueous solution of sulfuric acid. In the aqueous solution of sulfuric acid, the mass percentage of the solute is 55%. Prepare a mixture of ethanol and sodium nitrite. The mixture of ethanol and sodium nitrite is formed by mixing ethanol and sodium nitrite in a mass ratio of ethanol:sodium nitrite = 1:1.4. Place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed with ethanol coolant at -5°C as the coolant. The material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, add the aqueous solution of sulfuric acid dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed in 100 minutes. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material;

[0054] (2) Under the condition of an ice-water bath, add an aqueous solution of sodium hydroxide, hydrazine hydrate, and tetrabutylammonium hydroxide to the material collection bottle in sequence. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30%, and the solvent is water. The mass ratio of the product material, the aqueous solution of sodium hydroxide, hydrazine hydrate, and tetrabutylammonium hydroxide added is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:tetrabutylammonium hydroxide = 10:14:8:0.8. After the addition is completed, stir magnetically for 20 minutes under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 hours to obtain a mixture containing crude sodium azide;

[0055] (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70°C, precipitate crystals, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide product of this comparative example.

[0056] Comparative Example 3

[0057] A production process of sodium azide, the steps of which are as follows:

[0058] (1) Prepare an aqueous solution of sulfuric acid with a mass percentage of the solute of 55%. Prepare a mixture of ethanol and sodium nitrite, which is a mixture of ethanol and sodium nitrite mixed in a mass ratio of ethanol:sodium nitrite = 1:1.4. Place the mixture of ethanol and sodium nitrite in a conical flask. The conical flask is connected to a material collection bottle through a condenser. The condenser is passed with -5°C ethanol cold liquid as a coolant, and the material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and heat preservation. Then, add the aqueous solution of sulfuric acid dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 minutes. The mass ratio of the mixture of ethanol and sodium nitrite to the aqueous solution of sulfuric acid added dropwise is ethanol and sodium nitrite mixture:aqueous solution of sulfuric acid = 1:1. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material;

[0059] (2) Under the condition of an ice-water bath, add an aqueous solution of sodium hydroxide, hydrazine hydrate and an additive to the material collection bottle in sequence. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30% and the solvent is water. The dosage ratio of the aqueous solution of sodium hydroxide, hydrazine hydrate and the additive is product material:aqueous solution of sodium hydroxide:hydrazine hydrate:additive = 10g:14g:8g:2mL. After the addition is completed, stir magnetically for 20 minutes under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 14 hours to obtain a mixture containing crude sodium azide. The preparation method of the additive is as follows: Prepare an aqueous solution of p-toluenesulfonic acid and an ethanol solution of tributylamine. In the aqueous solution of p-toluenesulfonic acid, the concentration of p-toluenesulfonic acid is 18g / 100mL and the solvent is water. In the ethanol solution of tributylamine, the concentration of tributylamine is 4g / 100mL and the solvent is ethanol. Keep the ethanol solution of tributylamine in a water bath at a constant temperature of 6 ± 3°C for heat preservation, then stir the ethanol solution of tributylamine, and add the aqueous solution of p-toluenesulfonic acid to the solution under stirring. The volume ratio of the aqueous solution of p-toluenesulfonic acid added to the ethanol solution of tributylamine is ethanol solution of tributylamine:aqueous solution of p-toluenesulfonic acid = 10:3. After the addition is completed, keep it at 6 ± 3°C for 100 minutes, then remove ethanol and water by rotary evaporation under reduced pressure at 80°C. The obtained product is added to an aqueous solution of polyethylene glycol 1000. In the aqueous solution of polyethylene glycol 1000, the mass percentage of polyethylene glycol 1000 is 10%. The dosage ratio of the product added to the aqueous solution of polyethylene glycol 1000 is product:aqueous solution of polyethylene glycol 1000 = 1g:10mL. Obtain the additive;

[0060] (3) Open the material collection bottle, subject the mixture containing the crude sodium azide to dehydration under reduced pressure at 70 °C, precipitate crystals, perform solid-liquid separation, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide product of this comparative example.

[0061] Example 7

[0062] Test the purity and yield of sodium azide in the sodium azide products prepared by the methods described in the above examples and comparative examples. The results are shown in Table 1.

[0063] Table 1

[0064] Experimental group Purity of sodium azide Yield Example 1 99.6wt% 91.4％ Example 2 99.2wt% 92.1％ Example 3 99.5wt% 92.6％ Example 4 99.6wt% 91.8％ Example 5 99.4wt% 94.7％ Example 6 99.7wt% 95.0％ Comparative example 1 99.3wt% 68.2％ Comparative example 2 99.1wt% 79.5％ Comparative example 3 99.4wt% 86.3％

[0065] As can be seen from Table 1, the sodium azide prepared by the method of the present invention has a relatively high purity. After adding tetrabutylammonium hydroxide / additive and pyridine, the yield is significantly improved. This is mainly because tetrabutylammonium hydroxide or the additive can accelerate the progress of the sodium azide formation reaction and promote phase transfer. More sodium azide is obtained under the reaction time of the present invention, and the yield is relatively higher. Comparing Example 3, Example 6 and each comparative example, it can be seen that the addition of pyridine can optimize the above technical effects of tetrabutylammonium hydroxide or the additive, and the yield of the target product sodium azide obtained after adding pyrimidine to the reaction system is higher.

[0066] The technical solutions provided by the present invention have been introduced in detail above. For those of ordinary skill in the art, according to the idea of the embodiments of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A production process of high-purity sodium azide, characterized in that, The process steps are as follows: (1) Prepare an aqueous solution of sulfuric acid and a mixture of ethanol and sodium nitrite. Place the mixture of ethanol and sodium nitrite in a conical flask, which is connected to a material collection bottle through a condenser. The condenser is filled with ethanol coolant at -5°C, and the material collection bottle is placed in an ice-water bath. The conical flask is placed in a water bath at 35 ± 2°C for constant temperature and insulation. Then, add the aqueous solution of sulfuric acid dropwise to the mixture of ethanol and sodium nitrite. The addition of the aqueous solution of sulfuric acid is completed within 100 - 120 minutes. After the addition is completed, the conical flask continues to be kept at a constant temperature of 35 ± 2°C for more than 20 minutes. The product is condensed and refluxed through the condenser and then enters the material collection bottle to obtain the product material. (2) Under the condition of an ice-water bath, add an aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine to the material collection bottle in sequence. In the aqueous solution of sodium hydroxide, the mass percentage of the solute is 30%, and the solvent is water. The mass ratio of the product material, the aqueous solution of sodium hydroxide, hydrazine hydrate, tetrabutylammonium hydroxide, and pyridine is 10:12 - 16:7 - 9:0.6 - 1:0.3 - 0.

8. After the addition is completed, stir magnetically for 20 - 30 minutes under the condition of an ice-water bath, then seal the material collection bottle and place it in a water bath at 30 ± 3°C for static settlement for 12 - 16 hours to obtain a mixture containing crude sodium azide. (3) Open the material collection bottle, dehydrate the mixture containing crude sodium azide under reduced pressure at 70 - 75°C, precipitate crystals, separate the solid and liquid, wash the solid phase with ethanol, and dry it under vacuum conditions to obtain the sodium azide.

2. The production process of a high-purity sodium azide according to claim 1, characterized in that, In the aqueous solution of sulfuric acid, the mass percentage of the solute is 50% - 55%. The mixture of ethanol and sodium nitrite is ethanol and sodium nitrite with a mass ratio of ethanol:sodium nitrite = 1:1.2 - 1.

5.

3. The production process of a high-purity sodium azide according to claim 1, characterized in that, The mass ratio of adding the aqueous solution of sulfuric acid dropwise to the mixture of ethanol and sodium nitrite is mixture of ethanol and sodium nitrite:aqueous solution of sulfuric acid = 1 - 1.2:

1.

4. The production process of a high-purity sodium azide according to claim 1, characterized in that, Replace the tetrabutylammonium hydroxide with an additive. The preparation method of the additive is as follows: Prepare an aqueous solution of p-toluenesulfonic acid and an ethanol solution of tributylamine. Keep the ethanol solution of tributylamine in a water bath at 6 ± 3°C for constant temperature and insulation, then stir the ethanol solution of tributylamine. While stirring, add the aqueous solution of p-toluenesulfonic acid to the solution. After the addition is completed, keep it at 6 ± 3°C for more than 100 minutes, then carry out rotary evaporation under reduced pressure at 80°C to remove ethanol and water. Add the obtained product to an aqueous solution of polyethylene glycol 1000 to obtain the additive.

5. The production process of a highly pure sodium azide according to claim 4, characterized in that, In the aqueous solution of p-toluenesulfonic acid, the concentration of p-toluenesulfonic acid is 16 - 20 g / 100 mL, and the solvent is water. In the ethanol solution of tributylamine, the concentration of tributylamine is 3 - 5 g / 100 mL, and the solvent is ethanol. The volume ratio of adding the aqueous solution of p-toluenesulfonic acid to the ethanol solution of tributylamine is ethanol solution of tributylamine:aqueous solution of p-toluenesulfonic acid = 10:3 - 4.

6. The production process of a highly pure sodium azide according to claim 4, characterized in that, In the aqueous solution of polyethylene glycol 1000, the mass percentage content of polyethylene glycol 1000 is 10%, and the amount ratio of the product added to the aqueous solution of polyethylene glycol 1000 is product:aqueous solution of polyethylene glycol 1000 = 1 g:10 mL.

7. The production process of a high-purity sodium azide according to claim 4, characterized in that, The mass ratio of the added volume of the additive to the mass of the product material is product material:additive = 10 g:1 - 2 mL.