A method for preparing 2-nitropropane and a slurry-bed tubular reactor
By using a slurry-bed tubular reactor with ammonia, ozone, and acetone as raw materials, combined with a silicon-aluminum-titanium composite catalyst and deionized water, the safety risks and cost issues in the synthesis of 2-nitropropane were resolved, and high-yield industrial production was achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SUZHOU YACOO SCI CO LTD
- Filing Date
- 2024-12-27
- Publication Date
- 2026-06-30
AI Technical Summary
Existing methods for synthesizing 2-nitropropane are carried out under high temperature and high pressure, which poses safety risks, produces many byproducts, and results in low yields, making them unsuitable for industrial production.
Using ammonia, ozone, and acetone as starting materials, a silicon-aluminum-titanium composite catalyst treated with hydrogen peroxide was used in a slurry bed tubular reactor, combined with deionized water as a solvent, to generate 2-nitropropane through an oxidation reaction.
The reaction temperature was lowered, which improved safety and catalyst activity, extended catalyst life, increased reaction yield, and reduced production costs.
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Figure CN122301682A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of organic synthesis, and in particular to a method for preparing 2-nitropropane and a slurry-bed tubular reactor. Background Technology
[0002] 2-Nitropropane is widely used in the field of chemical synthesis as a solvent for various resins, waxes, fats, dyes and coatings, as well as an intermediate for the synthesis of pharmaceuticals, pesticides and other products.
[0003] Patent CA2720266A1 discloses a process for selectively generating 2-nitropropane and 2,2-dinitropropane. The process involves reacting propane with an aqueous nitric acid solution at a pressure of at least approximately 1000 psi and a temperature between approximately 215 and approximately 325 degrees Celsius to obtain 2-nitropropane and 2,2-dinitropropane. This process uses nitric acid as a raw material for the nitration reaction and is carried out under high temperature and pressure, which is relatively dangerous. Furthermore, it produces a large amount of the byproduct 2,2-dinitropropane, and the yield of the target compound 2-nitropropane is low. Separation of the product and byproduct requires distillation or rectification, thus hindering industrial production. Patent CN112321435A discloses a method for synthesizing 2-nitropropane. This method involves flowing a nitric acid-treated TS-1 catalyst solution, an acetone-methanol mixture, and hydrogen peroxide into a slurry bed, and then introducing ammonia gas to carry out the reaction at 70–75°C. This method uses methanol as a solvent and reacts in a slurry bed in a batch reactor. The reaction temperature is high, the reaction risk is high, and the cost is high, which is not conducive to industrial production.
[0004] Therefore, there is an urgent need to provide a new method for synthesizing 2-nitropropane that can not only guarantee high yields but also improve reaction safety and reduce costs. Summary of the Invention
[0005] In order to solve the above-mentioned technical problems, in a first aspect, this application provides a method for preparing 2-nitropropane, using ammonia, ozone and acetone as starting materials, and using a silicon-aluminum-titanium composite catalyst as catalyst, and continuously feeding and reacting in a slurry bed tubular reactor to obtain 2-nitropropane, wherein the silicon-aluminum-titanium composite catalyst is used after being treated with hydrogen peroxide.
[0006] By adopting the above technical solution, the preparation method provided in this application uses cleaner ozone as an oxidant and does not use methanol as a solvent as in the prior art, resulting in a significant reduction in reaction temperature and thus improving the reaction safety factor. Furthermore, the silicon-aluminum-titanium composite catalyst, after being treated with hydrogen peroxide, exhibits improved activity and a longer lifespan, allowing for repeated treatment and reuse. This not only improves the reaction yield but also reduces costs. Therefore, compared with the prior art, it not only ensures a high yield but also improves the reaction safety factor and reduces costs.
[0007] Preferably, the treatment method of the silicon-aluminum-titanium composite catalyst is as follows: 35% hydrogen peroxide is added to the silicon-aluminum-titanium composite catalyst, the temperature is raised to 80-90℃ and reacted for 4-6 hours. After the reaction is completed, the temperature is lowered to 10-25℃ and filtered. Then, the filtered silicon-aluminum-titanium composite catalyst is washed with deionized water until neutral, dried at 110-120℃ for 6-8 hours, and then calcined at 480-600℃ for 10-12 hours to obtain the final product.
[0008] Preferably, the treated silicon-aluminum-titanium composite catalyst has a particle size distribution of 800 nm to 1200 nm and / or a specific surface area of 280 m². 2 / g~390m 2 / g, and / or pore melt is 0.5~1.2mL / g.
[0009] By adopting the above technical solution, the silicon-aluminum-titanium composite catalyst can be treated to remove the carbon blocking the pores, thereby opening the pores and improving its catalytic effect. After multiple uses, it can be screened out and treated again using this method to open the pores again, thus allowing it to be reused, reducing production costs and facilitating industrial production.
[0010] Preferably, the molar ratio of acetone, ammonia and ozone is 1:(1-1.2):(2-2.5).
[0011] Preferably, before the reaction of ammonia, ozone and acetone, the treated silicon-aluminum-titanium composite catalyst is mixed with deionized water to form a slurry, and then the slurry is mixed with ammonia, ozone and acetone.
[0012] Preferably, the concentration of the treated silicon-aluminum-titanium composite catalyst in the slurry is 3-10%.
[0013] By adopting the above technical solution, this application uses deionized water as a solvent and does not use organic solvents such as methanol as a solvent, which greatly reduces production costs and greatly improves reaction safety.
[0014] Preferably, the slurry bed tubular reactor includes an oxidation reactor, a filtration device, a discharge device, an ammonia water conveying device, a first ozone generator, an acetone conveying device, and a second ozone generator connected in sequence, wherein the second ozone generator is connected to the oxidation reactor to form a circulating reaction system.
[0015] Preferably, the temperature of the first ozone generator and the second ozone generator is controlled between 25 and 50°C.
[0016] Preferably, the pressure inside the oxidation reactor is 0.1 to 0.3 MPa.
[0017] Preferably, the filtration device includes an organic PTFE filter membrane tube and an inorganic metal filter membrane tube arranged in series.
[0018] By adopting the above technical solution, the slurry bed tubular reactor used in this application can effectively separate the solvent deionized water and the reaction product 2-nitropropane by setting organic PTFE filter membrane tubes and inorganic metal filter membrane tubes, and the solvent can be reintroduced into the reaction system for reuse, which greatly saves costs.
[0019] Secondly, this application discloses a slurry bed tubular reactor, which includes an oxidation reactor, a filtration device, a discharge device, an ammonia water conveying device, a first ozone generator, an acetone conveying device, and a second ozone generator connected in sequence. The second ozone generator is further connected to the oxidation reactor to form a circulating reaction system.
[0020] Preferably, the filtration device includes an organic PTFE filter membrane tube and an inorganic metal filter membrane tube arranged in series.
[0021] In summary, this application has the following beneficial effects:
[0022] 1. The preparation method provided in this application uses cleaner ozone as an oxidant and does not use methanol as a solvent as in the prior art, resulting in a significant reduction in reaction temperature and thus improving the safety factor of the reaction. Furthermore, the silicon-aluminum-titanium composite catalyst, after being treated with hydrogen peroxide, exhibits improved activity and a longer lifespan, allowing for repeated treatment and reuse. This not only improves the reaction yield but also reduces costs.
[0023] 2. This application uses deionized water as a solvent and does not use organic solvents such as methanol, which greatly reduces production costs and greatly improves reaction safety.
[0024] 3. The slurry bed tubular reactor used in this application can effectively separate the solvent deionized water and the reaction product 2-nitropropane by setting organic PTFE filter membrane tubes and inorganic metal filter membrane tubes, and the solvent can be reintroduced into the reaction system for reuse, which greatly saves costs. Attached Figure Description
[0025] Figure 1 This is a structural diagram of a slurry bed tubular reactor.
[0026] Reference numerals: 1. Oxidation reactor; 2. Reactor circulation pump; 3. Filtration device; 31. Organic PTFE filter membrane tube; 32. Inorganic metal filter membrane tube; 33. Backflushing tank; 4. Discharge device; 41. Feed pump; 42. Product tank; 5. Ammonia water conveying device; 51. Ammonia water conveying pump; 52. First static mixer; 6. First ozone generator; 61. First ozone generator; 62. First ozone distributor; 63. Preheat exchanger; 7. Acetone conveying device; 71. Acetone conveying pump; 72. Second static mixer; 8. Second ozone generator; 81. Second ozone generator; 82. Second ozone distributor; 83. Postheat exchanger. Detailed Implementation
[0027] Example
[0028] The following is the specific structure of the slurry bed tubular reactor used in this application.
[0029] like Figure 1 As shown, the slurry-bed tubular reactor used in this application includes an oxidation reactor 1, a reactor circulation pump 2, a filter device 3, a discharge device 4, an ammonia water conveying device 5, a first ozone generator 6, an acetone conveying device 7, and a second ozone generator 8 connected in sequence. The second ozone generator 8 is connected to the oxidation reactor 1 to form a circulating reaction system. The slurry formed by deionized water and catalyst is introduced into the oxidation reactor 1 and then enters the entire slurry-bed tubular reactor through the reactor circulation pump 2.
[0030] The filtration device 3 includes an organic PTFE filter membrane tube 31, an inorganic metal filter membrane tube 32, and a backflushing tank 33. The organic PTFE filter membrane tube 31 and the inorganic metal filter membrane tube 32 are arranged in parallel and are respectively connected to the backflushing tank 33. The organic PTFE filter membrane tube 31 is connected to two feed pipes and two discharge pipes. One feed pipe is connected to the reactor circulation pump 2, so that the slurry enters the slurry bed system. The other feed pipe is connected to the backflushing tank 33 to clean the organic PTFE filter membrane tube 31 and maintain its filtration efficiency. One discharge pipe is connected to the discharge device 4 to facilitate the delivery of the reaction product 2-nitropropane out of the reactor. The other discharge pipe is connected to the ammonia water delivery device 5.
[0031] The inorganic metal filter membrane tube 32 is also connected to two feed pipes and two discharge pipes. One feed pipe is connected in parallel with one feed pipe of the organic PTFE filter membrane tube 31 and then connected to the reactor circulation pump 2. The other feed pipe is connected in parallel with the other feed pipe of the organic PTFE filter membrane tube 31 and then connected to the backflushing tank 33 to clean the inorganic metal filter membrane tube 32 and maintain its filtration efficiency. One discharge pipe is connected in parallel with one discharge pipe of the organic PTFE filter membrane tube 31 and then connected to the discharge device 4. The other discharge pipe is connected in parallel with the other discharge pipe of the organic PTFE filter membrane tube 31 and then connected to the ammonia water conveying device 5.
[0032] The discharge device 4 includes a feed pump 41 and a product tank 42 connected in series. The feed pump 41 is connected to the backflushing tank 33, and the product tank 42 is connected to another discharge pipe of the organic PTFE filter membrane tube 31 and the inorganic metal filter membrane tube 32.
[0033] The ammonia water delivery device 5 includes an ammonia water delivery pump 51 and a first static mixer 52 connected in series. The first static mixer 52 is connected to a first ozone generator 6.
[0034] The first ozone generating device 6 includes a first ozone generator 61, a first ozone distributor 62, and a preheater 63 connected in series. The first ozone distributor 62 is connected to a first static mixer 52, and the preheater 63 is connected to an acetone delivery device 7.
[0035] The acetone delivery device 7 includes an acetone delivery pump 71 and a second static mixer 72 connected in series. The second static mixer 7 is connected to a second ozone generator 8.
[0036] The second ozone generator 8 includes a second ozone generator 81, a second ozone distributor 82 and a post-heat exchanger 83 connected in series. The post-heat exchanger 83 is connected to the oxidation reactor 1 to form a circulating reaction system.
[0037] The following are examples of the preparation of silicon-aluminum-titanium composite catalysts.
[0038] Preparation Example 1
[0039] Add 35% hydrogen peroxide to the silicon-aluminum-titanium composite catalyst, heat to 80℃ and react for 6 hours. After the reaction is completed, cool down to 25℃ and filter. Then wash the filtered silicon-aluminum-titanium composite catalyst with deionized water until neutral, dry at 120℃ for 6 hours, and then calcine the dried silicon-aluminum-titanium composite catalyst at 600℃ for 10 hours to obtain the final product.
[0040] Preparation Example 2
[0041] Add 35% hydrogen peroxide to the silicon-aluminum-titanium composite catalyst, heat to 90℃ and react for 4 hours. After the reaction is completed, cool down to 10℃ and filter. Then wash the filtered silicon-aluminum-titanium composite catalyst with deionized water until neutral, dry at 110℃ for 8 hours, and then calcine the dried silicon-aluminum-titanium composite catalyst at 480℃ for 12 hours to obtain the final product.
[0042] Comparative Preparation Example 1
[0043] The silicon-aluminum-titanium composite catalyst can be used directly without any treatment.
[0044] Example 1
[0045] The following are examples of methods for preparing 2-nitropropane, in which the ammonia concentration is 28%.
[0046] Example 1
[0047] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1:2.04. 77.4 g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 1 and 1212.6 g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.2 MPa. Oxidation reactor 1 is opened for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 60.82 g / min to fully mix with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.96 g / min and reacts with the ammonia water solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 35°C. Acetone, supplied by acetone pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.96 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 35°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 99.9%, and the 2-nitropropane yield is 99.0%.
[0048] Example 2
[0049] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1.2:2. 129g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 2 and 1161g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.1MPa. Oxidation reactor 1 is turned on for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 72.98g / min to fully mix with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.00g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 25°C. Acetone, supplied by acetone pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.00 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 25°C before entering the oxidation reactor 1. The aqueous phase continuously exits through the inorganic metal filter membrane tube 32, and the organic phase continuously exits through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 99.2%, and the 2-nitropropane yield is 98.1%.
[0050] Example 3
[0051] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1.1:2.5. 38.7g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 1 and 1251.3g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.3MPa. Oxidation reactor 1 is opened for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 66.9g / min to fully mix with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 60.00g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 50°C. Acetone, pumped by acetone transfer pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 60.00 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 50°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 96.3%, and the 2-nitropropane yield is 94.4%.
[0052] Example 4
[0053] In this embodiment, the feed ratio of acetone, ammonia, and ozone is 1:2:2. 77.4 g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 1 and 1212.6 g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.2 MPa. Oxidation reactor 1 is turned on for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 121.64 g / min, thoroughly mixing with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.00 g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 35°C. Acetone, pumped by acetone transfer pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.00 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 35°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 99.0%, and the 2-nitropropane yield is 48.4%.
[0054] Example 5
[0055] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1:2.04. 12.9 g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 1 and 1277.1 g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.2 MPa. Oxidation reactor 1 is opened for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 60.82 g / min to fully mix with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.96 g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 35°C. Acetone, pumped by acetone transfer pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.96 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 35°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 92.3%, and the 2-nitropropane yield is 90.1%.
[0056] Example 6
[0057] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1:2.04. 77.4 g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 1 and 1212.6 g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.2 MPa. Oxidation reactor 1 is turned on for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 60.82 g / min, thoroughly mixing with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.96 g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 70°C. Acetone, pumped by acetone transfer pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.96 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 70°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 74.7%, and the 2-nitropropane yield is 43.8%.
[0058] Example 7
[0059] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1:2.04. 77.4 g of the silicon-aluminum-titanium composite catalyst prepared in Preparation Example 1 and 1212.6 g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.8 MPa. Oxidation reactor 1 is opened for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 60.82 g / min to fully mix with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.96 g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 35°C. Acetone, pumped by acetone transfer pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.96 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 35°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 92.2%, and the 2-nitropropane yield is 87.6%.
[0060] Comparative Example 1
[0061] In this embodiment, the molar ratio of acetone, ammonia, and ozone is 1:1:2.04. 77.4 g of the silicon-aluminum-titanium composite catalyst from Comparative Preparation Example 1 and 1212.6 g of deionized water are added to oxidation reactor 1. The pressure inside oxidation reactor 1 is controlled at 0.2 MPa. Oxidation reactor 1 is turned on for stirring to obtain a slurry, and reaction circulation pump 2 is turned on, allowing the slurry to enter the reaction system. Ammonia water delivered by ammonia water transfer pump 51 flows through the first static mixer 52 at a flow rate of 60.82 g / min, thoroughly mixing with the slurry. Ozone generated by the first ozone generator 61 and the first ozone distributor 62 enters the system at a flow rate of 48.96 g / min and reacts with the ammonia solution to generate hydroxylamine. The temperature of the section containing the first ozone generator 61, the first ozone distributor 62, and the preheater 63 is controlled at approximately 35°C. Acetone, pumped by acetone transfer pump 71, enters the system at a flow rate of 58.08 g / min and mixes with the generated hydroxylamine in the second static mixer 72. Then, it reacts with ozone generated by the second ozone generator 81 and the second ozone distributor 82 at a flow rate of 48.96 g / min to generate 2-nitropropane solution. After passing through the post-heat exchanger 83, the temperature of the 2-nitropropane solution is controlled at approximately 35°C before entering the oxidation reactor 1. The aqueous phase is continuously discharged through the inorganic metal filter membrane tube 32, and the organic phase is continuously discharged through the organic PTFE filter membrane tube to the product tank 42. The final acetone conversion rate is 81.7%, and the 2-nitropropane yield is 65.2%.
[0062] As can be seen from the above embodiments, the silicon-aluminum-titanium composite catalyst treated by the method of this application has a better catalytic effect.
[0063] The slurry bed tubular reactor provided in this application can effectively separate the aqueous phase and the oil phase by setting up an organic PTFE filter membrane tube 31 and an inorganic metal filter membrane tube 32, which is beneficial for the collection of reaction products.
[0064] The embodiments of this application illustrate that the preparation method described in this application can achieve a conversion rate of over 99% and a yield of over 99%. Furthermore, the use of clean energy sources such as ozone and deionized water in the reaction not only ensures a high yield but also improves the reaction safety factor and reduces costs.
[0065] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.
Claims
1. A process for the preparation of 2-nitropropane, characterized in that, Using ammonia, ozone, and acetone as starting materials, and a silicon-aluminum-titanium composite catalyst as the catalyst, 2-nitropropane is obtained by continuous feeding and reaction in a slurry bed tubular reactor. The silicon-aluminum-titanium composite catalyst is used after being treated with hydrogen peroxide.
2. The production method according to claim 1, characterized by, The processing method of the silicon-aluminum-titanium composite catalyst is as follows: 35% hydrogen peroxide is added to the silicon-aluminum-titanium composite catalyst, the temperature is raised to 80-90℃ and reacted for 4-6 hours. After the reaction is completed, the temperature is lowered to 10-25℃ and filtered. Then, the filtered silicon-aluminum-titanium composite catalyst is washed with deionized water until neutral, dried at 110-120℃ for 6-8 hours, and then calcined at 480-600℃ for 10-12 hours to obtain the final product.
3. The preparation method according to claim 1, characterized in that, The molar ratio of acetone, ammonia and ozone is 1:(1-1.2):(2-2.5).
4. The production method according to claim 2, characterized by, Before reacting with ammonia, ozone, and acetone, the treated silicon-aluminum-titanium composite catalyst is mixed with deionized water to form a slurry, and then the slurry is mixed with ammonia, ozone, and acetone. Preferably, the concentration of the treated silicon-aluminum-titanium composite catalyst in the slurry is 3-10%.
5. The preparation method according to claim 1, characterized in that, The slurry bed tubular reactor includes an oxidation reactor (1), a filter device (3), a discharge device (4), an ammonia water conveying device (5), a first ozone generator (6), an acetone conveying device (7), and a second ozone generator (8) connected in sequence. The second ozone generator (8) is further connected to the oxidation reactor (1) to form a circulating reaction system.
6. The production method according to claim 5, wherein The temperature of the first ozone generator (6) and the second ozone generator (8) is controlled between 25 and 50°C.
7. The preparation method according to claim 5, characterized in that, The pressure inside the oxidation reactor (1) is 0.1 to 0.3 MPa.
8. The preparation method according to claim 5, characterized in that, The filtration device (3) includes an organic PTFE filter membrane tube (31) and an inorganic metal filter membrane tube (32) arranged in parallel.
9. A slurry-bed tubular reactor used in the preparation method according to any one of claims 1-8, characterized in that, The slurry bed tubular reactor includes an oxidation reactor (1), a filter device (3), a discharge device (4), an ammonia water conveying device (5), a first ozone generator (6), an acetone conveying device (7), and a second ozone generator (8) connected in sequence. The second ozone generator (8) is further connected to the oxidation reactor (1) to form a circulating reaction system.
10. The slurry-bed tubular reactor according to claim 9, characterized in that, The filtration device (3) includes an organic PTFE filter membrane tube (31) and an inorganic metal filter membrane tube (32) arranged in parallel.