A decommissioned tnt catalytic hydrogenation process
By adding an appropriate amount of water to an organic solvent to form a mixed solvent system, the catalytic hydrogenation reaction conditions were optimized, solving the problem of small contact area of Pd/C catalyst in organic solvent, thus achieving efficient TAT production and reducing production costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- QILU UNIVERSITY OF TECHNOLOGY (SHANDONG ACADEMY OF SCIENCES)
- Filing Date
- 2023-12-27
- Publication Date
- 2026-05-19
AI Technical Summary
In the prior art, the small contact area between Pd/C catalyst and TNT in organic solvents leads to a decrease in the performance of catalytic hydrogenation reaction, requiring an increase in the amount of catalyst to ensure the yield of TAT, which increases the production cost.
Adding an appropriate amount of water to an organic solvent forms a mixed solvent system of organic solvent and water, which improves the utilization rate of the catalyst. The catalytic hydrogenation reaction is carried out by gas replacement and stirring, thus optimizing the reaction conditions.
This significantly improved the yield of TAT, reduced the amount of solid catalyst used, and lowered production costs.
Smart Images
Figure CN117756646B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of TNT catalytic hydrogenation technology, specifically relating to a decommissioned TNT catalytic hydrogenation process. Background Technology
[0002] The statements herein provide only background information in relation to this invention and do not necessarily constitute prior art.
[0003] Over time, a large quantity of 2,4,6-trinitrotoluene (TNT) munitions, which were deployed in the early stages due to historical reasons and wartime needs, have reached or are nearing their expiration date. Therefore, how to efficiently, safely, environmentally, and recycle these decommissioned TNT munitions for high-value utilization has become a major challenge. Catalytic hydrogenation of energetic TNT into the conventional chemical 2,4,6-triaminotoluene (TAT) is considered an important strategy for the resource utilization of decommissioned explosives.
[0004] Pd / C (palladium on carbon) catalysts, as the most classic catalysts for the liquid-phase hydrogenation reaction of nitro (-NO2), have advantages such as fast reaction rate, high conversion and selectivity, and good stability. Therefore, they have great application potential in the catalytic hydrogenation of decommissioned TNT. Since TNT itself is a hydrophobic organic compound, it needs to be dissolved in an organic solvent (ethanol, toluene, ethyl acetate, etc.) before the catalytic hydrogenation reaction. However, in industrial production, the use of large amounts of organic solvents inevitably increases the cost of waste treatment for production enterprises, reducing economic efficiency. At the same time, the inventors discovered that because Pd / C catalysts are hydrophilic solid catalysts, the contact angle between the catalyst and the organic solvent solution of the raw material is large and the contact area is small during the reaction in organic solvents. This significantly reduces the catalytic hydrogenation performance of the Pd / C catalyst itself. To ensure the yield of TAT, more Pd / C catalyst needs to be added, leading to an increase in the production cost of TAT. Summary of the Invention
[0005] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a catalytic hydrogenation process for decommissioned TNT, which can improve the performance of catalytic hydrogenation reaction under the same reaction conditions.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:
[0007] A catalytic hydrogenation process for decommissioned TNT includes the following steps: dissolving TNT in an organic solvent, then adding a solid catalyst and water to make the water content in the solvent reach 1%-95% by mass; sealing the reaction system, using hydrogen for gas replacement, and purging with hydrogen to reach a set pressure to carry out the catalytic hydrogenation reaction.
[0008] In some embodiments, the organic solvent is selected from toluene, 1,4-dioxane, N,N-dimethylacetamide (DMAC), N,N-dimethylformamide (DMF), ethanol, acetonitrile, ethyl acetate, tetrahydrofuran, or a mixture thereof.
[0009] Preferably, the organic solvent is ethyl acetate or ethanol.
[0010] In some embodiments, the solvent contains 5%-95% water by mass.
[0011] Preferably, the solvent contains 10%-90% water by mass.
[0012] More preferably, the solvent contains 20%-85% water by mass.
[0013] In a further preferred embodiment, the solvent contains 40%-85% water by mass, preferably 60%-85%, more preferably 75%-85%, and especially 78%-82%; specifically 80%.
[0014] In some embodiments, hydrogen gas is introduced into the closed reaction system to a pressure of 0.5-1.5 MPa.
[0015] Preferably, hydrogen gas is introduced into the closed reaction system to a pressure of 0.7-1.2 MPa.
[0016] In some embodiments, the temperature of the catalytic hydrogenation reaction is 30-130°C, and the reaction time is 5-30 min.
[0017] Preferably, the temperature of the catalytic hydrogenation reaction is 60-80℃ and the reaction time is 10-20 min.
[0018] In some embodiments, the reaction system is stirred during the catalytic hydrogenation reaction.
[0019] In some embodiments, the solid catalyst for catalytic hydrogenation is a Pd / C catalyst, and the mass ratio of TNT to Pd / C catalyst is 3-5:0.05-0.15.
[0020] Preferably, the mass ratio of TNT to Pd / C catalyst is 3-5:0.05-0.1.
[0021] Preferably, the mass percentage of Pd in the solid catalyst is 1%-10%, more preferably 5%.
[0022] In some embodiments, the mass ratio of TNT to organic solvent is 0.2-100:100.
[0023] Preferably, the mass ratio of TNT to organic solvent is 2-50:100;
[0024] More preferably, the mass ratio of TNT to organic solvent is 2-30:100.
[0025] The beneficial effects achieved by one or more embodiments of the present invention described above are as follows:
[0026] When the catalytic hydrogenation reaction of TNT is carried out in a mixed solvent of organic solvent and water, the yield of TAT can be significantly improved, especially when the volume ratio of organic solvent to water is close to 1:4, the yield of TAT can reach 100%.
[0027] When using the organic solvent and water mixture system of the present invention, the utilization rate of solid catalyst is effectively improved. Under the premise of achieving a high TAT yield, the amount of solid catalyst can be greatly reduced, thereby reducing the production cost of TAT. Attached Figure Description
[0028] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0029] Figure 1 This is a liquid chromatogram of the product after the catalytic hydrogenation reaction of decommissioned TNT in Example 1 of the present invention (500 mL ethyl acetate + 0 mL water);
[0030] Figure 2 This is a liquid chromatogram of the product after the catalytic hydrogenation reaction of decommissioned TNT in Example 1 of the present invention (100 mL ethyl acetate + 400 mL water);
[0031] Figure 3 This is a liquid chromatogram of the product after the catalytic hydrogenation reaction of decommissioned TNT in Example 1 of the present invention (0 mL ethyl acetate + 500 mL water);
[0032] Figure 4 This is a liquid chromatogram of the product after the catalytic hydrogenation reaction of decommissioned TNT in Example 2 of the present invention (500 mL ethanol + 0 mL water);
[0033] Figure 5 This is a liquid chromatogram of the product after the catalytic hydrogenation reaction of decommissioned TNT in Example 2 of the present invention (100 mL ethanol + 400 mL water). Detailed Implementation
[0034] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0035] The present invention will be further described below with reference to the embodiments.
[0036] Experiments on organic solvents:
[0037] The decommissioning of the TNT catalytic hydrogenation process includes the following steps:
[0038] Add 3.5g of TNT solid to a high-temperature, high-pressure reactor, add a certain amount of organic solvent and stir to dissolve. Then add 180mg of commercial 5% Pd / C catalyst, and replenish with the same solvent to a final volume of 500mL. Close the reactor lid and replace the air in the reactor with 1MPa N2 three times. Replace the N2 in the reactor with 1MPa H2 three times, and finally purge with 1MPa H2. Stir the reaction solution at 200r / min, and simultaneously raise the temperature to 70℃ and hold for 15min to complete the reaction. Discharge the reaction solution through the bottom outlet of the reactor for testing.
[0039] Using the above catalytic hydrogenation process, the yield of TAT corresponding to different organic solvents (toluene, 1,4-dioxane, N,N-dimethylformamide (DMAC), N,N-dimethylformamide (DMF), ethanol, acetonitrile, ethyl acetate, tetrahydrofuran) is shown in Table 1.
[0040] Table 1 Catalytic hydrogenation performance of decommissioned TNT under different organic solvent conditions
[0041] Serial Number Solvent (500mL) TAT yield % 1 Toluene 1.1％ 2 1,4-Dioxane 42.6 3 DMAC 7.7 4 DMF 39.1 5 ethanol 98.4 6 Acetonitrile 81.1 7 Ethyl acetate 99.5 8 Tetrahydrofuran 78.9
[0042] As shown in Table 1, the yield of TAT is higher when the organic solvents are ethyl acetate and ethanol. Therefore, ethyl acetate and ethanol were chosen for subsequent experiments.
[0043] Example 1
[0044] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0045] Add 3.5g of solid TNT to a high-temperature, high-pressure reactor, add a certain amount of ethyl acetate and stir to dissolve, then add 90mg of commercial 5% Pd / C catalyst, followed by a certain amount of water. Close the reactor lid and replace the air in the reactor with 1MPa N2 three times; replace the N2 in the reactor with 1MPa H2 three times, and finally purge with 1MPa H2. Stir the reaction solution at 200 rpm while simultaneously raising the temperature to 70℃ and holding for 15 minutes to complete the reaction. Discharge the reaction solution through the bottom outlet of the reactor for testing.
[0046] Using the above catalytic hydrogenation process, the amounts of ethyl acetate and water added were adjusted, ensuring a total solvent volume of 500 mL. The liquid chromatograms of the products after catalytic hydrogenation reactions for different solvent systems are shown below. Figures 1-3 As shown in Table 2, the yield of TAT is as follows.
[0047] Table 2 Catalytic hydrogenation performance of decommissioned TNT under different solvent ratios
[0048]
[0049] As shown in Table 1, the TAT yield was 40.2% in the pure ethyl acetate system and 40.5% in the pure water system. However, the TAT yield increased significantly to 100% in the 100 mL ethyl acetate + 400 mL water system. This is mainly because the raw material TNT cannot dissolve in the pure water system, while the solid catalyst in the pure ethyl acetate system is a hydrophilic catalyst.
[0050] Example 2
[0051] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0052] Add 3.5g of solid TNT to a high-temperature, high-pressure reactor, add a certain amount of ethanol and stir to dissolve, then add 90mg of commercial 5% Pd / C catalyst, and then add a certain amount of water; close the lid of the high-temperature, high-pressure reactor, replace the air in the reactor with 1MPa N2 three times; replace the N2 in the reactor with 1MPa H2 three times, and finally purge with 1MPa H2; stir the reaction solution at 200r / min, and simultaneously raise the temperature to 70℃ and hold for 15min to complete the reaction. Discharge the reaction solution through the bottom outlet of the reactor for testing.
[0053] Using the above catalytic hydrogenation process, the amounts of ethanol and water added were adjusted, and the total volume of solvent was kept to be 500 mL. The yields of TAT for different solvent systems are shown in Table 3.
[0054] Table 3 Catalytic hydrogenation performance of decommissioned TNT under different solvent ratios
[0055]
[0056] Example 3
[0057] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0058] Add 3.5g of solid TNT to a high-temperature, high-pressure reactor, add 100mL of ethyl acetate and stir to dissolve. Then add a certain amount of commercial 5% Pd / C catalyst (30mg, 60mg, 90mg), followed by 400mL of water. Close the reactor lid and replace the air in the reactor with 1MPa N2 three times. Replace the N2 in the reactor with 1MPa H2 three times, and finally purge with 1.0MPa H2. Stir the reaction solution at 200r / min while simultaneously raising the temperature to 70℃ and holding for 15min to complete the reaction. Discharge the reaction solution through the bottom outlet of the reactor for analysis. The yield of TAT is shown in Table 4.
[0059] Table 4 Catalytic hydrogenation performance of decommissioned TNT under different catalyst dosages
[0060] Serial Number Catalyst dosage (mg) TAT yield % 1 30 69.6 2 60 88.2 3 90 100
[0061] Example 4
[0062] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0063] Add 3.5g of solid TNT to a high-temperature, high-pressure reactor, add 100mL of ethyl acetate and stir to dissolve. Then add 30mg of commercial 5% Pd / C catalyst and 400mL of water. Close the reactor lid and replace the air in the reactor with 1MPa N2 three times. Replace the N2 in the reactor with 1.0MPa H2 three times, and finally purge with 1.0MPa H2. Stir the reaction solution at 200r / min and simultaneously raise the temperature to a certain temperature (30℃, 50℃, 70℃, 100℃, 130℃), hold for 15min, and the reaction is complete. Discharge the reaction solution through the bottom outlet of the reactor for analysis. The yield of TAT is shown in Table 5.
[0064] Table 5 Catalytic hydrogenation performance of decommissioned TNT at different reaction temperatures
[0065]
[0066]
[0067] Example 5
[0068] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0069] Add 3.5g of solid TNT to a high-temperature, high-pressure reactor, add 100mL of ethyl acetate and stir to dissolve. Then add 30mg of commercial 5% Pd / C catalyst and 400mL of water. Close the reactor lid and replace the air in the reactor with 1MPa N2 three times. Replace the N2 in the reactor with 1.0MPa H2 three times. Finally, purge with H2 to a certain pressure (0.5MPa, 1.0MPa, 1.5MPa). Stir the reaction solution at 200r / min and simultaneously raise the temperature to 70℃ and hold for 15min to complete the reaction. Discharge the reaction solution through the bottom outlet of the reactor for analysis. The yield of TAT is shown in Table 6.
[0070] Table 6 Catalytic hydrogenation performance of decommissioned TNT under different hydrogen pressures
[0071] Serial Number Reaction pressure (MPa) TAT yield % 1 0.5 65.8 2 1.0 69.6 3 1.5 71.2
[0072] Example 6
[0073] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0074] Add 3.5g of solid TNT to a high-temperature, high-pressure reactor, add 100mL of ethyl acetate and stir to dissolve. Then add 30mg of commercial 5% Pd / C catalyst and 400mL of water. Close the reactor lid and replace the air in the reactor with 1MPa N2 three times. Replace the N2 in the reactor with 1.0MPa H2 three times, and finally purge with 1.0MPa H2. Stir the reaction solution at speeds of 100, 200, 300, and 400 r / min, while simultaneously raising the temperature to 70℃ and holding for 15min. The reaction is then complete. Discharge the reaction solution through the bottom outlet of the reactor for analysis. The yield of TAT is shown in Table 7.
[0075] Table 7 Catalytic hydrogenation performance of decommissioned TNT at different stirring speeds
[0076] Serial Number Stirring speed (r / min) TAT yield % 1 100 52.1 2 200 69.6 3 300 70.2 4 400 66.5
[0077] Example 7
[0078] A decommissioned TNT catalytic hydrogenation process includes the following steps:
[0079] 3.5 g of solid TNT was added to a high-temperature, high-pressure reactor, followed by 100 mL of ethyl acetate and stirring to dissolve. Then, 30 mg of Pd / C catalysts with different Pd mass fractions (3%, 4%, 5%) were added, along with 400 mL of water. The reactor lid was closed, and the air inside the reactor was replaced three times with 1 MPa of N2. The N2 inside the reactor was then replaced three times with 1.0 MPa of H2, and finally, 1.0 MPa of H2 was introduced. The reaction solution was stirred at speeds of 100, 200, 300, and 400 r / min, while simultaneously heating to 70 °C and holding at this temperature for 15 min. The reaction was then complete. The resulting solution was discharged through the bottom outlet of the reactor for analysis. The TAT yield is shown in Table 8.
[0080] Table 8 Catalytic hydrogenation performance of decommissioned TNT under different catalyst types
[0081] Serial Number Pd mass fraction % TAT yield % 1 3 51.6 2 4 58.3 3 5 69.6
[0082] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A catalytic hydrogenation process for decommissioned TNT, characterized in that: The process includes the following steps: TNT is first dissolved in an organic solvent, then a solid catalyst and water are added to make the water content in the solvent reach 60%-90% by mass; after sealing the reaction system, hydrogen is used for gas replacement, and hydrogen is introduced to reach the set pressure to carry out the catalytic hydrogenation reaction. The organic solvent is selected from one or a mixture of ethanol, acetonitrile, ethyl acetate, and tetrahydrofuran; The solid catalyst for catalytic hydrogenation is a Pd / C catalyst, with a mass ratio of TNT to Pd / C catalyst of 3-5:0.05-0.
15.
2. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: The organic solvent is ethyl acetate or ethanol.
3. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: The solvent contains 60%-85% water by mass.
4. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: The solvent contains 75%-85% water by mass.
5. The decommissioned TNT catalytic hydrogenation process according to claim 4, characterized in that: The solvent contains 78%-82% water by mass.
6. The decommissioned TNT catalytic hydrogenation process according to claim 5, characterized in that: The solvent contains 80% water by mass.
7. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: Hydrogen gas is introduced into the closed reaction system to a pressure of 0.5-1.5 MPa.
8. The decommissioned TNT catalytic hydrogenation process according to claim 7, characterized in that: Hydrogen gas is introduced into the closed reaction system to a pressure of 0.7-1.2 MPa.
9. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: The temperature for catalytic hydrogenation is 30-130℃, and the reaction time is 5-30 min.
10. The decommissioned TNT catalytic hydrogenation process according to claim 9, characterized in that: The temperature for catalytic hydrogenation is 60-80℃, and the reaction time is 10-20 min.
11. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: During the catalytic hydrogenation reaction, the reaction system is stirred.
12. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: The mass ratio of TNT to Pd / C catalyst is 3-5:0.05-0.
1.
13. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: In the solid catalyst, the mass percentage of Pd is 1%-10%.
14. The decommissioned TNT catalytic hydrogenation process according to claim 13, characterized in that: The solid catalyst contains 5% Pd by mass.
15. The decommissioned TNT catalytic hydrogenation process according to claim 1, characterized in that: The mass ratio of TNT to organic solvent is 0.2-100:
100.
16. The decommissioned TNT catalytic hydrogenation process according to claim 15, characterized in that: The mass ratio of TNT to organic solvent is 2-50:
100.
17. The decommissioned TNT catalytic hydrogenation process according to claim 16, characterized in that: The mass ratio of TNT to organic solvent is 2-30:100.