Glycerol trinitrate / diethylene glycol dinitrate mixture, kettle type overflow synthesis method and application
The preparation process of liquid nitrate ester mixtures is simplified by using a batch overflow synthesis method, which solves the problems of multiple steps and high safety risks in the existing technology, and achieves high-yield mixture preparation, which is suitable for propellant and propellant applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- XIAN MODERN CHEM RES INST
- Filing Date
- 2025-12-26
- Publication Date
- 2026-04-10
AI Technical Summary
In the existing technology, the synthesis method of liquid nitrate ester mixture is complicated, involves many steps, and has safety risks, resulting in low product yield and difficulty in meeting the needs of large-scale application.
A mixture of glycerol trinitrate and diethylene glycol dinitrate was prepared by using an overflow reactor method, which simplifies the process, reduces the amount of work done online, and improves safety through continuous reactor nitration and post-treatment.
The process operation was simplified, the safety of the nitration reaction and the product yield were improved, and a high yield of glycerol trinitrate/diethylene glycol dinitrate mixture was achieved, which is suitable for the preparation of propellants and propellants.
Abstract
Description
TECHNICAL FIELD
[0001] The present application belongs to the technical field of organic synthesis, and relates to a liquid nitrate mixture, in particular to a glycerol trinitrate / diethylene glycol dinitrate mixture, a kettle overflow synthesis method and application. BACKGROUND
[0002] Liquid nitrate-based energetic plasticizers represented by nitroglycerin are an effective technical approach to improving the energy of propellant formulations and the mechanical properties thereof. Such compounds have high energy, large density and low cost, and are the most commonly used energetic plasticizers in double-base propellants. Nitroglycerin (NG) is a typical representative of nitrate-based energetic plasticizers. However, NG has the disadvantages of high sensitivity and easy volatilization. When subjected to external impact, friction or other stimuli, NG is prone to cause explosion. In addition, NG has a high freezing point (13.2℃), which leads to poor low-temperature mechanical properties of double-base propellants, and is not suitable for storage and combat requirements in severe cold environments, and has poor environmental adaptability, and even causes bore explosion and other launch safety accidents. Therefore, in the application of formulations, NG is replaced by diethylene glycol dinitrate (DEGDN) mixed ester, which has lower sensitivity and better chemical stability, and can improve the safety and migration at low temperatures, and is the most commonly used NG substitute in solid propellants and propellants in recent years. Currently, the NG / DEGDN mixed nitrate is obtained by separately nitration and corresponding post-processing to obtain NG and DEGDN single components, and then mixed according to the required proportion. This process not only has many operation procedures, but also needs stirring and other procedures in the mixing process of nitrate, which has high safety risk for NG and other highly sensitive nitrates, limits the large-scale application of mixed nitrates, and needs to be improved. SUMMARY
[0003] In view of the deficiencies of the prior art, the purpose of the present application is to provide a glycerol trinitrate / diethylene glycol dinitrate mixture, a kettle overflow synthesis method and application, so as to solve the technical problems of many process operation procedures and low product yield of the existing synthesis method.
[0004] In order to solve the above technical problems, the technical scheme is adopted as follows.
[0005] A kettle overflow synthesis method of a glycerol trinitrate / diethylene glycol dinitrate mixture, comprising the following steps: Step 1, mixing concentrated nitric acid and concentrated sulfuric acid to prepare nitric-sulfuric mixed acid; mixing glycerol and diethylene glycol to obtain mixed polyols; Step 2, continuously pumping the formula amount of nitric-sulfuric mixed acid and mixed polyols into the overflow type reaction kettle by means of a metering pump for nitration reaction, and the reaction product flows out of the overflow port of the reaction kettle and enters the separator; Step 3: Separate the organic phase in the separator; Step 4: After washing with water and alkali, the organic phase is collected in a collection tank to obtain a mixture of glycerol trinitrate and diethylene glycol dinitrate.
[0006] The present invention also has the following technical features: Specifically, in step 1, the mass ratio of concentrated nitric acid to concentrated sulfuric acid is 1:1; the mass ratio of glycerol to diethylene glycol is (1~4):1.
[0007] Furthermore, in step 2, the temperature of the nitration reaction is 10℃~20℃; the reaction time is 5min~30min; and the stirring speed of the reactor is 100 rpm~300 rpm.
[0008] Furthermore, in step 2, the nitration reaction temperature is 15°C; the reaction time is 10 min; and the stirring speed of the reactor is 200 rpm.
[0009] Furthermore, in step 2, the mass ratio of the nitrate-sulfur mixed acid and the mixed polyol entering the reactor per unit time is (3~10):1.
[0010] Furthermore, in step 4, the volumetric flow rate ratio of the organic phase to the washing water is (0.5~2):1.
[0011] Furthermore, in step 4, the volume flow rate ratio of the organic phase to the alkaline solution used for alkaline washing is (0.5~2):1.
[0012] Furthermore, in step 4, the alkaline solution is selected from any one of sodium carbonate aqueous solution, sodium bicarbonate aqueous solution, and sodium hydroxide aqueous solution.
[0013] The present invention also protects the mixture of glycerol trinitrate / diethylene glycol dinitrate, which is prepared by the above-described batch overflow synthesis method.
[0014] The present invention also protects the use of the glycerol trinitrate / diethylene glycol dinitrate mixture prepared by the above-described batch overflow synthesis method for the preparation of propellants or propellants.
[0015] Compared with the prior art, the present invention has the following technical effects.
[0016] The method of this invention adopts a batch overflow synthesis method, which simplifies the process operation, reduces the amount of reaction in the online process, improves the safety of the nitration process, and increases the reaction yield of the glycerol trinitrate / diethylene glycol dinitrate mixture.
[0017] The specific content of the present invention will be further explained in detail below with reference to the embodiments. Detailed Implementation
[0018] It should be noted that, unless otherwise specified, all raw materials and equipment used in this invention are those known in the prior art.
[0019] The technical concept of this invention is as follows: To address the problems of complex batch synthesis-post-treatment-mixing processes, large online volumes, and high safety risks in the preparation of liquid mixed nitrates, this study seeks a simpler, smaller-volume, and safer synthesis method. Based on the principle of continuous reaction in an overflow reactor, an overflow reactor is used for the nitration reaction, followed by continuous post-treatment, eliminating the need for additional mixing and simplifying the process.
[0020] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.
[0021] Example 1 Following the above technical solution, this embodiment provides a batch overflow synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate, comprising the following steps: Step 1: Mix concentrated nitric acid and concentrated sulfuric acid in a 1:1 mass ratio to prepare a nitric-sulfuric acid mixture; mix glycerol and diethylene glycol in a 3:1 mass ratio to obtain a mixed polyol; Step 2: The mixed nitrate-sulfur acid and the mixed polyol are simultaneously introduced into the overflow reactor at flow rates of 50 g / min and 10 g / min respectively through metering pumps. The reaction products flow out of the reactor through the overflow port and enter the separator. The reaction temperature is 15℃, the residence time of the nitration reaction is 10 min, and the stirring speed of the reactor is 200 rpm.
[0022] Step 3: Separate the organic phase in the separator; Step 4: After separation by the separator, the organic phase flows into a three-stage scrubber. Washing water (or alkaline solution) is introduced into the scrubber at a rate of 4 mL / min to sequentially wash the organic phase with water, then with alkaline solution, and finally with water again. The alkaline solution is selected from any one of 10-15% sodium carbonate aqueous solution, 10-15% sodium bicarbonate aqueous solution, and 5-10% sodium hydroxide aqueous solution. The washed organic phase flows into a collection tank, and the organic phase is collected for 10 min to obtain 168.2 g of mixed nitrate ester, with a yield of 85.1%.
[0023] According to the 1H NMR spectroscopy analysis, the NG content in the mixed nitrate ester was 1% and the DEGDN content was 24.8%.
[0024] The glycerol trinitrate / diethylene glycol dinitrate mixture prepared in this embodiment can be used to prepare propellants. During preparation, the amount of glycerol trinitrate / diethylene glycol dinitrate mixture added is 20%~50%.
[0025] Example 2 This embodiment provides a batch overflow synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate. The steps and raw materials used in this method are the same as in Example 1, except that in step 1, Glycerin and diethylene glycol were mixed in a 1:1 mass ratio to form a mixed polyol.
[0026] In this embodiment, 151.7 g of mixed nitrate ester was finally obtained, with a yield of 75.4%.
[0027] According to the 1H NMR spectroscopy analysis, the NG content in the mixed nitrate ester was 52.5% and the DEGDN content was 47.5%.
[0028] Example 3 This embodiment provides a batch overflow synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate. The steps and raw materials used in this method are the same as in Example 1, except that in step 1, Concentrated nitric acid and concentrated sulfuric acid are mixed in a mass ratio of 3:1 to prepare a nitric acid-sulfuric acid mixture.
[0029] In this embodiment, 135.8 g of mixed nitrate ester was finally obtained, with a yield of 67.5%.
[0030] Nuclear magnetic resonance (NMR) 1H spectroscopy analysis revealed that the mixed nitrate ester contained 72.5% NG and 27.5% DEGDN. Example 4 This embodiment provides a batch overflow synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate. The steps and raw materials used in this method are the same as those in Example 1, except that in step 2, the mixed nitric acid and mixed polyol are simultaneously introduced into the overflow reactor through metering pumps at flow rates of 100 g / min and 10 g / min, respectively, for reaction.
[0031] In this embodiment, 120.1 g of mixed nitrate ester was finally obtained, with a yield of 59.7%.
[0032] According to the 1H NMR spectroscopy analysis, the NG content in the mixed nitrate ester was 78.1% and the DEGDN content was 21.9%.
[0033] Example 5 The example provides a batch overflow synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate. The steps and raw materials used in this method are the same as those in Example 1, except that in step 2, the reaction temperature is 20°C, the residence time of the nitration reaction is 10 min, and the stirring speed of the reactor is 200 rpm.
[0034] In this embodiment, 150.1 g of mixed nitrate ester was finally obtained, with a yield of 74.6%.
[0035] According to the 1H NMR spectroscopy analysis, the NG content in the mixed nitrate ester was 71.7% and the DEGDN content was 28.3%.
[0036] Comparative Example 1 This comparative example provides a conventional batch reactor synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate, comprising the following steps: Step 1: Mix concentrated nitric acid and concentrated sulfuric acid in a 1:1 mass ratio to prepare a nitric-sulfuric acid mixture; mix glycerol and diethylene glycol in a 3:1 mass ratio to obtain a mixed polyol; Step 2: Add 500g of nitrate-sulfur mixed acid to the reactor, control the temperature at 15℃, turn on the reactor stirring at 200 rpm, add 100g of mixed polyol to the reactor through a metering pump to carry out the nitration reaction, control the feeding rate to keep the temperature at about 15℃, and continue the reaction for 10 minutes after the mixed alcohol is added, then stop stirring. Step 3: Separate the organic phase in the reactor; Step 4: The organic phase is added to the reactor, followed by washing water and alkali solution. The organic phase is then washed sequentially with water, alkali, and water. After three washings, the organic phase flows into a collection tank, yielding 114.6 g of mixed nitrate ester, with a yield of 58.0%. According to the 1H NMR spectroscopy analysis, the mixed nitrate ester contained 77.2% NG and 22.8% DEGDN.
[0037] As can be seen from Examples 1-5 and Comparative Example 1: Changing the content of nitric acid and sulfuric acid in the nitrate-sulfur mixture, adjusting the mass ratio of the nitrate-sulfur mixture to the mixed polyol, and increasing the temperature of the nitration reaction will all lead to a decrease in the yield of the nitrate ester mixture. Changing the mass ratio of glycerol to diethylene glycol in the mixed polyol will change the mass ratio of the two components in the prepared nitrate ester mixture, which will not meet the requirements of the product application.
[0038] Compared with existing batch reactor synthesis methods, the method of this invention can simplify process operation, reduce the amount of reaction in the process, improve the safety of the nitration process, and increase product yield. The reaction yield of the glycerol trinitrate / diethylene glycol dinitrate mixture can reach 85.1%.
[0039] The preferred embodiments of this disclosure have been described in detail above. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.
[0040] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.
[0041] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.
Claims
1. A batch overflow synthesis method for a mixture of glycerol trinitrate and diethylene glycol dinitrate, characterized in that, Includes the following steps: Step 1: Mix concentrated nitric acid and concentrated sulfuric acid to prepare a nitric-sulfuric acid mixture; mix glycerol and diethylene glycol to obtain a mixed polyol; Step 2: Using a metering pump, the prescribed amount of nitrate-sulfur mixed acid and mixed polyol are continuously pumped into an overflow reactor for nitration reaction. The reaction products flow out of the reactor through the overflow port and enter the separator. Step 3: Separate the organic phase in the separator; Step 4: After washing with water and alkali, the organic phase is collected in a collection tank to obtain a mixture of glycerol trinitrate and diethylene glycol dinitrate.
2. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 1, the mass ratio of concentrated nitric acid to concentrated sulfuric acid is 1:1; the mass ratio of glycerol to diethylene glycol is (1~4):
1.
3. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 2, the temperature of the nitration reaction is 10℃~20℃; the reaction time is 5min~30min; and the stirring speed of the reactor is 100 rpm~300 rpm.
4. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 2, the nitration reaction temperature is 15℃; the reaction time is 10 min; and the stirring speed of the reactor is 200 rpm.
5. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 2, the mass ratio of the mixed nitrate-sulfur acid and the mixed polyol entering the reactor per unit time is (3~10):
1.
6. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 4, the volumetric flow rate ratio of the organic phase to the washing water is (0.5~2):
1.
7. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 4, the volume flow rate ratio of the organic phase to the alkaline solution used for alkaline washing is (0.5~2):
1.
8. The batch overflow synthesis method for the glycerol trinitrate / diethylene glycol dinitrate mixture as described in claim 1, characterized in that, In step 4, the alkaline solution is selected from any one of sodium carbonate aqueous solution, sodium bicarbonate aqueous solution, and sodium hydroxide aqueous solution.
9. A mixture of glycerol trinitrate and diethylene glycol dinitrate, characterized in that, It is prepared by the batch overflow synthesis method as described in any one of claims 1 to 8.
10. The use of the glycerol trinitrate / diethylene glycol dinitrate mixture prepared by the batch overflow synthesis method as described in any one of claims 1 to 8 for the preparation of propellants.