Continuous process for the synthesis of 2,4,6-triamino-5-nitropyrimidine
By using a CSTR reactor and optimized molar ratio control, continuous synthesis of TANP was achieved, solving the problems of low efficiency and safety hazards in the semi-batch process, and realizing high-yield and low-cost TANP production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- NANJING UNIV OF SCI & TECH
- Filing Date
- 2022-10-31
- Publication Date
- 2026-07-24
AI Technical Summary
The existing semi-batch synthesis process of TANP has problems such as low production efficiency, easy agglomeration of raw materials, incomplete reaction, great safety hazards and high raw material costs.
Continuous synthesis of TANP was achieved using a CSTR reactor, with the reaction temperature controlled between 10 and 30°C. The molar ratio of fuming nitric acid to concentrated sulfuric acid was 1:6 to 9.2, the molar ratio of TAP to concentrated sulfuric acid was 1:5 to 6.7, and the molar ratio of fuming nitric acid to concentrated sulfuric acid was 1:1 to 6.7. The materials were uniformly transported by a peristaltic pump. After the reaction, the process included quenching, alkali washing, acetone washing, and drying.
This improved reaction efficiency and safety, reduced the consumption of fuming nitric acid and concentrated sulfuric acid, avoided solid precipitation, and achieved high-yield and low-cost TANP production.
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Figure CN117946010B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a continuous synthesis method for 2,4,6-triamino-5-nitropyrimidine (TANP), belonging to the field of energetic materials synthesis. Background Technology
[0002] In recent years, novel high-energy insensitive energetic materials have developed rapidly. Compared with widely used triaminotrinitrobenzene (TATB) and 1,3,5,7-tetranitro-1,3,5,7-tetraazacyclooctane (HMX), 2,4,6-triamino-5-nitropyrimidine-1,3-dioxide (ICM-102), as a novel high-energy insensitive explosive, has the characteristics of high energy density, good detonation performance, and high stability. Moreover, its synthesis steps are simpler and the cost is relatively low, making it one of the hot topics for future development of novel high-energy insensitive energetic materials. 2,4,6-triamino-5-nitropyrimidine (TANP), as a key intermediate in the synthesis of ICM-102, requires continuous optimization in its synthesis process.
[0003] Currently, the domestic preparation of TANP mainly adopts a semi-batch process (Wang Yi, Liu Yuji, Song Siwei, et al. Accelerating the discovery of insensitive high energy-density materials by a materials genome approach[J]. Nature Communications, 2018, 9(1): 1-11.), which uses 2,4,6-triaminopyrimidine (TAP) as raw material, fuming nitric acid as nitrating agent, and concentrated sulfuric acid as dehydrating agent, and adopts a solid feeding method. The ratio of TAP to fuming nitric acid and concentrated sulfuric acid is 1:11.98:9.39, which has low production efficiency. During the feeding process, the raw materials are prone to agglomeration or adsorption on the reaction vessel wall, resulting in incomplete reaction and safety hazards. In addition, the sulfuric acid dehydration value (value is 12.16) of the existing process is low, while the nitric acid ratio (value is 11.98) is quite high, resulting in insufficient utilization of nitric acid and high economic cost of raw materials. Summary of the Invention
[0004] To overcome the shortcomings of existing semi-batch TANP synthesis methods, such as large online production volume and low synthesis efficiency, this invention provides a TANP synthesis method. This method enables continuous TANP synthesis, improves reaction efficiency by using a CSTR reactor while ensuring yield, reduces the consumption of fuming nitric acid and concentrated sulfuric acid, and eliminates solid precipitation during the reaction process, resulting in a small online production volume and significantly improved safety and production efficiency.
[0005] The technical solution of the present invention is as follows:
[0006] A continuous synthetic method for 2,4,6-triamino-5-nitropyrimidine, the synthetic equation is as follows:
[0007]
[0008] The specific steps are as follows:
[0009] First, concentrated sulfuric acid containing fuming nitric acid is added to the reactor as a base material. At a reaction temperature of 10–30°C, a mixed solution of 2,4,6-triaminopyrimidine (TAP) and concentrated sulfuric acid, as well as a mixed acid of fuming nitric acid and concentrated sulfuric acid, are added. Simultaneously, a peristaltic pump draws the material online into a buffer reactor, where the reaction is carried out at a constant temperature. Finally, the product is obtained after quenching, alkali washing, acetone washing, filtration, and drying. The molar ratio of fuming nitric acid to concentrated sulfuric acid in the concentrated sulfuric acid is 1:6–9.2; the molar ratio of TAP to concentrated sulfuric acid in the TAP / concentrated sulfuric acid mixed solution is 1:5–6.7; and the molar ratio of fuming nitric acid to concentrated sulfuric acid in the mixed acid is 1:1–6.7.
[0010] Preferably, the molar ratio of TAP, fuming nitric acid and concentrated sulfuric acid is 1:1.2-3:8-9.4.
[0011] Preferably, the residence time of the material in the reactor is 60 to 100 minutes.
[0012] Preferably, the heat preservation reaction time is 40–60 min.
[0013] Preferably, the alkaline washing is performed using a sodium carbonate solution.
[0014] Preferably, the drying method is vacuum drying, the drying temperature is 50℃, the vacuum degree is 0.07MPa, and the drying time is 4 to 6 hours.
[0015] Compared with existing semi-intermittent synthesis methods, the significant advantages of this invention are:
[0016] (1) The reaction process is a homogeneous liquid-liquid reaction, with more uniform heat release and easier control of the synthesis process; (2) The amount of material online is small, which greatly improves the safety performance of the system; (3) The reaction system is a homogeneous system, which effectively reduces the waste of raw materials and prevents solid from sticking to the wall; (4) The sulfuric acid dehydration value is increased, the nitric acid ratio is greatly reduced, and the nitric acid is fully utilized. Compared with the traditional semi-batch method, the reaction efficiency is greatly improved, and it is easy to realize automated industrial production. Attached Figure Description
[0017] Figure 1 This is a flowchart of the apparatus for continuous synthesis of TANP according to the present invention.
[0018] Figure 2 The image shows the TANP high-performance liquid chromatography (HPLC) test results.
[0019] Figure 3 The image shows the TANP NMR characterization results. Detailed Implementation
[0020] The present invention will be further illustrated by specific embodiments below.
[0021] Example 1
[0022] At room temperature, 25.8 g of TAP and 57.9 mL of concentrated sulfuric acid were prepared as raw material one, and 10.2 mL of fuming nitric acid and 40.4 mL of concentrated sulfuric acid were prepared as raw material two. Simultaneously, 42.6 mL of concentrated sulfuric acid and 0.7 mL of fuming nitric acid were added to 1.7 mL of water as a base. The molar ratio of TAP to concentrated sulfuric acid in raw material one was 1:5.3, and the molar ratio of fuming nitric acid to concentrated sulfuric acid in raw material two was 1:3.1. The molar ratio of TAP to fuming nitric acid to concentrated sulfuric acid in both raw materials was 1:1.2:9.0. Under these process conditions, the sulfuric acid dehydration value was 22.01, and the nitric acid ratio was 1.20. Two feedstocks were simultaneously pumped into a reactor containing a base material. The reaction temperature was 10°C, and the residence time was 80 min. The resulting 2,4,6-triamino-5-nitropyrimidine reaction solution was then passed into a buffer reactor and kept at that temperature for another 30 min. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 90.76%, and the purity was 95.42%.
[0023] Example 2
[0024] At room temperature, 25.8 g of TAP and 57.9 mL of concentrated sulfuric acid were prepared as raw material one, and 10.2 mL of fuming nitric acid and 40.4 mL of concentrated sulfuric acid were prepared as raw material two. Simultaneously, 42.6 mL of concentrated sulfuric acid and 0.7 mL of fuming nitric acid were added to 1.7 mL of water as a base. The molar ratio of TAP to concentrated sulfuric acid in raw material one was 1:5.3, and the molar ratio of fuming nitric acid to concentrated sulfuric acid in raw material two was 1:3.1. The molar ratio of TAP to fuming nitric acid to concentrated sulfuric acid in both raw materials was 1:1.2:9.0. Under these process conditions, the sulfuric acid dehydration value was 22.01, and the nitric acid ratio was 1.20. Two feedstocks were simultaneously pumped into a reactor containing a base material. The reaction temperature was 20°C, and the residence time was 80 min. The resulting 2,4,6-triamino-5-nitropyrimidine reaction solution was then passed into a buffer reactor and kept at that temperature for another 30 min. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 91.95%, and the purity was 96.83%.
[0025] The product TANP was analyzed by HPLC and characterized by NMR. The results are shown in the figure. Figure 2 , Figure 3 As shown.
[0026] Example 3
[0027] At room temperature, 25.8 g of TAP and 57.9 mL of concentrated sulfuric acid were prepared as raw material one, and 10.2 mL of fuming nitric acid and 40.4 mL of concentrated sulfuric acid were prepared as raw material two. Simultaneously, 42.6 mL of concentrated sulfuric acid and 0.7 mL of fuming nitric acid were added to 1.7 mL of water as a base. The molar ratio of TAP to concentrated sulfuric acid in raw material one was 1:5.3, and the molar ratio of fuming nitric acid to concentrated sulfuric acid in raw material two was 1:3.1. The molar ratio of TAP to fuming nitric acid to concentrated sulfuric acid in both raw materials was 1:1.2:9.0. Under these process conditions, the sulfuric acid dehydration value was 22.01, and the nitric acid ratio was 1.20. Two feedstocks were simultaneously pumped into a reactor containing a base material. The reaction temperature was 30°C, and the residence time was 80 min. The resulting 2,4,6-triamino-5-nitropyrimidine reaction solution was then passed into a buffer reactor and kept at that temperature for another 30 min. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 94.37%, and the purity was 97.53%.
[0028] Example 4
[0029] At room temperature, 25.8 g of TAP and 57.9 mL of concentrated sulfuric acid were prepared as raw material one, and 10.2 mL of fuming nitric acid and 40.4 mL of concentrated sulfuric acid were prepared as raw material two. Simultaneously, 42.6 mL of concentrated sulfuric acid and 0.7 mL of fuming nitric acid were added to 1.7 mL of water as a base. The molar ratio of TAP to concentrated sulfuric acid in raw material one was 1:5.5, and the molar ratio of fuming nitric acid to concentrated sulfuric acid in raw material two was 1:3.1. The molar ratio of TAP to fuming nitric acid to concentrated sulfuric acid in both raw materials was 1:1.2:9.0. Under these process conditions, the sulfuric acid dehydration value was 22.01, and the nitric acid ratio was 1.20. Two feedstocks were simultaneously pumped into a reactor containing a base material. The reaction temperature was 30°C, and the residence time was 100 min. The resulting 2,4,6-triamino-5-nitropyrimidine reaction solution was then passed into a buffer reactor and kept at that temperature for another 30 min. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 94.27%, and the purity was 98.13%.
[0030] Comparative Example 1
[0031] Using 15g of solid TAP as raw material, 60mL of fuming nitric acid and 60mL of concentrated sulfuric acid were prepared as the base. The molar ratio of TAP to concentrated sulfuric acid to fuming nitric acid was 1:9.39:11.98. Under these process conditions, the sulfuric acid dehydration value was 12.16, and the nitric acid ratio was 11.98. TAP was added in small amounts multiple times to the reactor containing the base. The reaction temperature was 10℃, and after the addition was complete, the temperature was maintained for 30 minutes. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 91.74%, and the purity was 97.13%.
[0032] Comparative Example 2
[0033] At room temperature, 25.8 g of TAP and 57.9 mL of concentrated sulfuric acid were prepared as raw materials, and 10.2 mL of fuming nitric acid and 47.1 mL of concentrated sulfuric acid were prepared as the base. The molar ratio of TAP to concentrated sulfuric acid in the raw materials was 1:5.05, and the molar ratio of fuming nitric acid to concentrated sulfuric acid in the base was 1:3.5. The molar ratio of the total amount of TAP, fuming nitric acid, and concentrated sulfuric acid in the raw materials was 1:1.2:8.55. Under these conditions, the sulfuric acid dehydration value was 22.69, and the nitric acid ratio was 1.20. The raw materials were pumped into the reactor containing the base materials using a plunger pump. The reaction temperature was 30°C, and after the addition was completed, the temperature was maintained for 30 min. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 94.68%, and the purity was 97.26%.
[0034] Comparative Example 3
[0035] At room temperature, 25.8 g of TAP and 57.9 mL of concentrated sulfuric acid were prepared as raw material one, and 10.2 mL of fuming nitric acid and 40.4 mL of concentrated sulfuric acid were prepared as raw material two. Simultaneously, 42.6 mL of concentrated sulfuric acid and 0.7 mL of fuming nitric acid were added to 1.7 mL of water as a base. The molar ratio of TAP to concentrated sulfuric acid in raw material one was 1:5.3, and the molar ratio of fuming nitric acid to concentrated sulfuric acid in raw material two was 1:3.1. The molar ratio of TAP to fuming nitric acid to concentrated sulfuric acid in both raw materials was 1:1.2:9.0. Under these process conditions, the sulfuric acid dehydration value was 22.01, and the nitric acid ratio was 1.20. Two feedstocks were simultaneously pumped into a reactor containing a base material. The reaction temperature was 35°C, and the residence time was 80 min. The resulting 2,4,6-triamino-5-nitropyrimidine reaction solution was then passed into a buffer reactor and kept at that temperature for another 30 min. Finally, the reaction solution was quenched in an ice-water mixture. After the product precipitated, it was filtered, washed with alkali, water, and acetone to obtain a pale yellow solid TANP. The yield was 82.16%, and the purity was 83.49%.
Claims
1. A continuous method for the synthesis of 2,4,6-triamino-5-nitropyrimidine, characterized in that, The specific steps are as follows: First, concentrated sulfuric acid containing fuming nitric acid is added to the reactor as a base material. At a reaction temperature of 10-30°C, a TAP / concentrated sulfuric acid mixed solution and a fuming nitric acid / concentrated sulfuric acid mixed acid are added. Simultaneously, a peristaltic pump draws the online material into a buffer reactor, where the reaction is carried out at a constant temperature. Finally, the product is obtained after quenching, alkali washing, acetone washing, filtration, and drying. The molar ratio of fuming nitric acid to concentrated sulfuric acid in the concentrated sulfuric acid is 1:6-9.2; the molar ratio of TAP to concentrated sulfuric acid in the TAP / concentrated sulfuric acid mixed solution is 1:5-6.7; the molar ratio of fuming nitric acid to concentrated sulfuric acid in the fuming nitric acid / concentrated sulfuric acid mixed acid is 1:1-6.7; and the molar ratio of TAP, fuming nitric acid, and concentrated sulfuric acid is 1:1.2-3:8-9.
4.
2. The continuous synthesis method according to claim 1, characterized in that, The residence time of the material in the reactor is 60-100 minutes.
3. The continuous synthesis method according to claim 1, characterized in that, The heat preservation reaction time is 40~60 minutes.
4. The continuous synthesis method according to claim 1, characterized in that, Alkaline washing involves cleaning with a sodium carbonate solution.
5. The continuous synthesis method according to claim 1, characterized in that, The drying method is vacuum drying, the drying temperature is 50℃, the vacuum degree is 0.07MPa, and the drying time is 4~6h.