Continuous reaction system and continuous method for producing 2-amino-2-methyl-1-propanol

Abstract

The present invention provides a continuous reaction system and a continuous method for producing 2-amino-2-methyl-1-propanol. The continuous reaction system includes: a first continuous module, a second continuous module and a third continuous module, the first continuous module includes a first continuous reaction module, the first continuous reaction module is used to carry out continuous oximation reaction and continuous oxidation reaction on the first raw material in sequence, and obtain a first product system; the second continuous module includes a second continuous reaction module, and the second continuous reaction module is used to carry out continuous condensation reaction on the raw material including solution C, solution D and the first product system, and obtain a second product system; the third continuous module includes a third continuous reaction module, and the third continuous reaction module is used to carry out continuous hydrogenation reaction on the raw material including solution E and hydrogen, and obtain a third product system containing 2-amino-2-methyl-1-propanol. The system can continuously produce 2-amino-2-methyl-1-propanol with high efficiency and low input.

Description

Technical Field

[0001] The invention relates to the technical field of 2-amino-2-methyl-1-propanol preparation, and in particular to a continuous reaction system and a continuous method for producing 2-amino-2-methyl-1-propanol. Background Art

[0002] 2-Amino-2-methyl-1-propanol, also known as isobutanolamine, can be used to synthesize many important high-value-added fine chemicals, and as a functional reagent to modify polymer materials. It is widely used in medicine, coatings, adhesives, rubber, personal care products, and amine absorption method to capture carbon dioxide. At the same time, its wide application in these fields has promoted the development of its synthesis process.

[0003] In terms of reaction route, the production of isobutanolamine in current industrial production mainly includes the following processes:

[0004] (1) Using acetone as raw material, H 2 O 2 2-nitropropane is synthesized by using nitropropane as an oxidant and ammonia water as an ammonia source. Nitropropane and formaldehyde react to first produce 2-nitro-2-methyl-1-propanol (NMP), and then undergo hydrogenation to produce isobutanolamine (AMP). This route is widely used in the industrial production of isobutanolamine because the starting materials used are all cheap and readily available, the reaction route is simple and direct, and the intermediates are stable and easy to separate.

[0005] (2) Using an alcohol solution of α-aminoisobutyric acid alkyl ester as a raw material, AMP is prepared by one-step hydrogenolysis reduction in the presence of a noble metal, Raney nickel or copper-based catalyst;

[0006] (3) Using isobutylene as a raw material, isobutylene and chlorine are introduced into acetonitrile to react under acidic conditions to obtain N-[1-(chloromethyl)propyl]acetyl chloride, and then water is added to cause N-[1-(chloromethyl)propyl]acetyl chloride to undergo a first hydrolysis reaction to obtain N-[1-(chloromethyl)propyl]acetamide. N-[1-(chloromethyl)propyl]acetamide is subjected to a second hydrolysis reaction to obtain the target product AMP.

[0007] However, based on the synthesis route with acetone as the main raw material, the reported synthesis process and equipment have one or more of the following disadvantages when analyzing each step of the reaction:

[0008] A Chinese patent with a patent application publication number of CN106045859A provides a method for preparing 2-nitropropane, in which acetone, an ammonia source and hydrogen peroxide are used as a solvent, and the reaction is carried out under the action of a TS-1 titanium silicon molecular sieve catalyst. However, the reaction time is 4 to 10 hours, which is relatively long. After the reaction is completed, the selectivity of acetone oxime generated in the system is 25 to 50%, indicating that the utilization rate of hydrogen peroxide is low, and a large part of the reaction remains in the acetone oxime intermediate state.

[0009] A Chinese patent with a patent application publication number of CN108178731A provides a one-pot green synthesis method for preparing AMP-95. The patent adopts a process flow of directly adding hydrogen peroxide to a mixture of acetone, ammonia and a catalyst under high temperature. Because hydrogen peroxide accelerates its decomposition rate under high temperature, there are certain operational risks in long-term dropwise operation under heating. After the reaction is completed, alkali and raw material formaldehyde are directly added after filtration. If there is any hydrogen peroxide left in the system, there will be risks in the filtration process and formaldehyde will also be oxidized and lost.

[0010] The Chinese patent with patent application publication number CN108976128A uses an acidic solid catalyst to remove formaldehyde. The process is as follows: first, the alkali in the system is removed by an acidic purification resin, then the formaldehyde is converted into methylal by an acidic solid catalyst, the methylal is removed by distillation, and then the concentrated liquid is crystallized and dried to obtain a solid product. Although this method is effective in removing formaldehyde, it requires a large amount of acidic resin to neutralize the alkalinity in the system, which not only increases the equipment cost, but also makes the process complicated, making it difficult to achieve industrial production.

[0011] Therefore, in order to solve the problems of low production efficiency and yield, poor catalyst selectivity and large dosage requirement, and high formaldehyde residue in the intermittent process production of 2-amino-2-methyl-1-propanol, it is urgent to develop a system and method for producing 2-amino-2-methyl-1-propanol. Summary of the invention

[0012] The main purpose of the present invention is to provide a continuous reaction system and a continuous method for producing 2-amino-2-methyl-1-propanol, so as to solve the problems of low production efficiency and yield, poor catalyst selectivity, large dosage requirement and high formaldehyde residue in the batch process of producing 2-amino-2-methyl-1-propanol in the prior art.

[0013] In order to achieve the above-mentioned purpose, according to one aspect of the present invention, a continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol is provided, the continuous reaction system comprising: a first continuous module, a second continuous module and a third continuous module, the first continuous module comprising a first continuous reaction module, the first continuous reaction module comprising a first inlet and a first outlet, the first inlet being respectively connected to a first raw material source comprising a solution A source and a solution B source, the first continuous reaction module being used for sequentially performing a continuous oximation reaction and a continuous oxidation reaction on the first raw material to obtain a first product system containing 2-nitropropane, wherein solution A comprises acetone, an ammonia source and a first solvent, and solution B comprises hydrogen peroxide and a second solvent; the second continuous module comprising a second continuous reaction module, the second continuous reaction module comprising a second inlet and a second outlet, the second inlet being respectively connected to a solution C source, a solution D source and the first outlet, the second continuous reaction module being used for performing a continuous condensation reaction on the raw materials comprising solution C, solution D and the first product system to obtain a second product system containing 2-nitro-2-methyl-1-propanol, wherein solution C comprises formaldehyde and a third solvent, and solution D comprises an alkaline substance and a fourth solvent; a third continuous module, including a third continuous reaction module, the third continuous reaction module including a third inlet and a third outlet, the third inlet is respectively connected to a raw material source including a solution E source and a hydrogen source, the solution E source comes out of the second outlet and enters the third continuous reaction module through the third inlet, the third continuous reaction module is used to continuously hydrogenate the raw material including the solution E and hydrogen to obtain a third product system containing 2-amino-2-methyl-1-propanol, wherein the solution E includes the second product system and the fifth solvent; wherein the first continuous reaction module includes: a solid A fixed-bed reaction device comprises M fixed-bed reactors, each of which is provided with N interconnected catalytic units, 1≤M, 1≤N, M and N are not 1 at the same time, and each fixed-bed reactor is provided with a feed inlet and a discharge port; each catalytic unit independently comprises a catalyst bed layer and a material bed layer interconnected with each other, the material bed layer is between two adjacent catalyst beds, and each material bed layer has a solution B inlet; solution B is respectively introduced into the catalytic unit from each solution B inlet and the feed inlet of the fixed-bed reactor, and solution A is simultaneously introduced into the feed inlet of the fixed-bed reactor.

[0014] Furthermore, M fixed bed reactors are arranged in series, 1≤M≤10; and / or, the catalyst beds in each catalytic unit are arranged in series, the catalyst beds are arranged in stages, and the catalyst beds are 1 to 10 stages; and / or, the number of solution B inlets in each catalytic unit is 1 to 9.

[0015] Furthermore, 3≤M≤6; and / or, the catalyst bed is 3-6 levels, and the number of solution B inlets in each catalytic unit is 2-5.

[0016] Furthermore, the first continuous module also includes a first gas-liquid separation module and a first distillation treatment module, which are sequentially arranged on the connecting pipeline between the first continuous module and the second continuous module; the first gas-liquid separation module is used to perform a first continuous gas-liquid separation treatment on the first product system to obtain a degassed product system and gas impurities; the first distillation treatment module is used to perform a first distillation treatment on the degassed product system to obtain 2-nitropropane and acetone oxime; and / or, the temperature of the first continuous reaction module is controlled by jacket temperature control, the preheating temperature of the first continuous reaction module is 30~60°C, and the insulation temperature of the first continuous reaction module is 50~80°C; and / or, the pressure of the first continuous reaction module is 0.5~10MPa.

[0017] Furthermore, the second continuous module also includes a continuous formaldehyde removal module and a second distillation treatment module, and the continuous formaldehyde removal module and the second distillation treatment module are sequentially arranged on the connecting pipeline between the second continuous module and the third continuous module; the continuous formaldehyde removal module is used to perform continuous formaldehyde removal treatment on the second product system to obtain a product system and gas impurities after formaldehyde removal; the second distillation treatment module is used to perform a second distillation treatment on the product system after formaldehyde removal to obtain 2-nitro-2-methyl-1-propanol; and / or, the second continuous reaction module is a plug flow reactor; the temperature of the second continuous reaction module is controlled by jacket temperature control, the preheating temperature of the second continuous reaction module is 20~50℃, and the insulation temperature of the second continuous reaction module is 20~60℃; and / or, the continuous formaldehyde removal module is a fixed bed formaldehyde removal tower, and the tower body, top and bottom of the fixed bed formaldehyde removal tower are sequentially provided with a feed inlet, a top discharge port and a bottom discharge port. inlet, the number of feed inlets is 1 to 5; the fixed bed aldehyde removal tower has a first inner tower wall and a second inner tower wall relative to each other, and a plurality of aldehyde removal catalyst beds arranged at intervals and interconnected are sequentially arranged along the direction of material flow in the fixed bed aldehyde removal tower, and any two adjacent aldehyde removal catalyst beds have gaps between the first inner tower wall and the second inner tower wall, respectively, and the gaps are used for the circulation of the second product system; and / or the aldehyde removal catalyst beds are 10 to 50 levels; and / or each aldehyde removal catalyst bed is filled with catalyst B, and catalyst B is methylal resin and / or sulfonic acid resin; and / or, the area of ​​the radial cross section of the fixed bed aldehyde removal tower is S1, and the projected area of ​​each aldehyde removal catalyst bed projected on the radial cross section of the fixed bed aldehyde removal tower is S2, S1 / S2>50%; and / or, the temperature of the continuous aldehyde removal module is controlled by jacket temperature control, and the insulation temperature of the continuous aldehyde removal module is 20 to 60°C.

[0018] Furthermore, the third continuous module also includes a second gas-liquid separation module, a third distillation treatment module and a product continuous receiving module, and the second gas-liquid separation module and the third distillation treatment module are sequentially arranged on the connecting pipeline between the third continuous module and the product continuous receiving module; the second gas-liquid separation module is used to perform continuous gas-liquid separation treatment on the third product system to obtain a third degassed product system and gas impurities; the third distillation treatment module is used to perform a third distillation treatment on the third degassed product system to obtain 2-amino-2-methyl-1-propanol; and / or, the temperature of the third continuous reaction module is controlled by jacket temperature control, the preheating temperature of the third continuous reaction module is 20~50°C, the insulation temperature of the third continuous reaction module is 30~100°C, and / or, the pressure of hydrogen in the third continuous reaction module is 0.5~4.0MPa.

[0019] According to another aspect of the present invention, there is provided a continuous method for preparing 2-nitro-2-methyl-1-propanol by using the above-mentioned continuous reaction system, and the continuous method comprises: step S1, sequentially subjecting a first raw material comprising acetone, an ammonia source, hydrogen peroxide, a first solvent and a second solvent to an oximation reaction and an oxidation reaction with a catalyst A to obtain a first product system containing 2-nitropropane; step S2, subjecting a second raw material comprising 2-nitropropane, formaldehyde, an alkaline substance, a third solvent and a fourth solvent to a condensation reaction to obtain a second product system containing 2-nitro-2-methyl-1-propanol; and step S3, subjecting a third raw material comprising 2-nitro-2-methyl-1-propanol, hydrogen and a fifth solvent to a hydrogenation reaction with a catalyst C to obtain a third product system containing 2-amino-2-methyl-1-propanol.

[0020] Further, the above step S1 also includes: step S11, mixing raw materials including acetone, an ammonia source and a first solvent to obtain solution A; step S12, mixing raw materials including hydrogen peroxide and a second solvent to obtain solution B; step S13, sequentially performing oximation reaction and oxidation reaction on the first raw material including solution A and solution B and catalyst A to obtain a first product system; step S14, sequentially performing a first continuous gas-liquid separation treatment and a first distillation treatment on the first product system to obtain 2-nitropropane and acetone oxime; wherein the molar ratio of acetone to the ammonia source is 1:1~1:10, and the ratio of the mass of acetone to the volume of the first solvent is 1:1~1:20g / mL; and / or, the molar ratio of acetone to hydrogen peroxide is 1:1~1:10; and / or, catalyst A is a spherical titanium oxide silicon molecular sieve with a particle size of 3~5mm, and / or, the loading amount of catalyst A is 10~80% of the volume of the fixed bed reaction device; and / or, The first solvent and the second solvent are each independently selected from any one or more of methanol, ethanol, n-butanol, isobutanol, tert-butanol, isopropanol, ethylene glycol, water, N,N-dimethylacetamide, dimethyl sulfoxide, ethyl acetate and isopropyl acetate; and / or, the ammonia source is selected from any one or more of ammonia gas, liquid ammonia, ammonia water and an organic ammonia solution; wherein the mass content of ammonia water is 5-40%; the mass content of ammonia gas in the organic ammonia solution is 2-50%, and / or, the organic solvent in the organic ammonia solution is selected from any one or more of methanol, ethanol and ethyl acetate; and / or, the total reaction time of the oximation reaction and the oxidation reaction is 5-100 min; the reaction temperature of the oximation reaction and the oxidation reaction is each independently 30-100° C.; the reaction pressure of the oximation reaction and the oxidation reaction is each independently 0.5-6.0 MPa; the temperature of the first continuous gas-liquid separation treatment is 15-25° C., and the temperature of the first distillation treatment is 25-80° C.

[0021] Further, the above step S2 also includes: step S21, mixing the raw materials including formaldehyde and the third solvent to obtain solution C; step S22, mixing the raw materials including the alkaline substance and the fourth solvent to obtain solution D; step S23, condensing the second raw material including 2-nitropropane, solution C, and solution D to obtain a second product system; step S24, sequentially performing continuous formaldehyde removal treatment and second distillation treatment on the second product system to obtain 2-nitro-2-methyl-1-propanol; wherein the alkaline substance is an organic alkaline substance and / or an inorganic alkaline substance, and / or the organic alkaline substance is selected from any one or more of trimethylamine, triethylamine, N,N-diisopropylethylamine, N,N,N',N'-tetramethylethylenediamine, 1,8-diazabicycloundec-7-ene, pyridine, N-methyltetrahydropyrrole and triethylenediamine; and / or the inorganic alkaline substance is selected from any one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate, phosphoric acid Any one or more of potassium, potassium acetate and potassium tert-butoxide; and / or, the source material of formaldehyde is paraformaldehyde and / or formaldehyde aqueous solution; wherein the mass content of formaldehyde aqueous solution is 5-40%; and / or, the molar ratio of 2-nitropropane to alkaline substance is 1:0.001-1:0.5, and the molar ratio of 2-nitropropane to formaldehyde is 1:1-1:5; and / or, the third solvent and the fourth solvent are each independently selected from methanol, ethanol, n-butanol, isobutanol, tert-butanol, isopropanol , any one or more of ethylene glycol, water, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, N-methylpyrrole, ethyl acetate, isopropyl acetate and butyl acetate; and / or, the reaction temperature of the condensation reaction is 20~80°C, and the reaction time of the condensation reaction is 10~30min; and / or, the temperature of the second distillation treatment is 40~80°C; the temperature of the continuous formaldehyde removal treatment is 20~60°C, and the time of the continuous formaldehyde removal treatment is 10~60min.

[0022] Furthermore, the above step S3 also includes: step S31, mixing the raw materials including 2-nitro-2-methyl-1-propanol and the fifth solvent to obtain solution E; step S32, hydrogenating the third raw material including solution E and hydrogen with catalyst C to obtain a third product system; step S33, sequentially performing a second continuous gas-liquid separation treatment and a third distillation treatment on the third product system to obtain 2-amino-2-methyl-1-propanol; wherein the mass ratio of 2-nitro-2-methyl-1-propanol to the fifth solvent is The molar ratio of hydrogen to solution E is 1:0.5-1:20, the fifth solvent is selected from any one or more of benzene, toluene, methanol, ethanol, dichloromethane, tetrahydrofuran and N,N-dimethylformamide; and / or the molar ratio of hydrogen to solution E is 3:1-10:1; and / or the reaction time of the hydrogenation reaction is 10-60 min, and the reaction pressure of the hydrogenation reaction is 0.5-3.0 MPa; and / or the temperature of the second continuous gas-liquid separation treatment is 15-40° C., and the temperature of the third distillation treatment is 40-130° C.

[0023] Applying the technical scheme of the present invention, the present invention provides a continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol with high efficiency and low investment, wherein each fixed bed reactor included in the fixed bed reaction device has a large heat exchange area, can quickly remove the reaction heat, realize accurate temperature control and high reaction selectivity, and at the same time, the contact interface of the liquid-solid two phases in the fixed bed reactor is large, and the reaction rate is fast, so that the process can be easily amplified. In the present application, the storage capacity of hydrogen peroxide is small, and hydrogen peroxide is simultaneously introduced through the feed port of the fixed bed reactor and the solution B inlet of the material bed layer, so that multi-point feeding can be realized in the fixed bed reaction device, so that hydrogen peroxide is not easy to decompose, and the utilization rate of hydrogen peroxide is improved, while better heat transfer efficiency can be achieved, thereby avoiding the use of hydrogen peroxide for oxidation reaction in intermittent reaction. Not only is it dangerous and exothermic, but hydrogen peroxide is easy to decompose at high temperature, resulting in a low utilization rate; thereby effectively reducing transportation risks and reducing costs. The raw materials including solution C, solution D and the first product system can be fully mixed by the second continuous module, so as to avoid the deterioration of the intermediate, and then improve the reaction yield, while avoiding the reaction system when there is uneven local material step or temperature control is not stable, causing the reaction product 2-nitro-2-methyl-1-propanol to decompose back to 2-nitropropane and formaldehyde under the action of a strong base. By the third continuous module, the raw materials including solution E, hydrogen and the second product system are continuously hydrogenated, and the selectivity of 2-nitro-2-methyl-1-propanol can be further improved compared to batch process, so as to reduce the reaction pressure. The above-mentioned solvent of the present invention is easy to recover, has a higher utilization rate, so as to effectively reduce costs. The present invention adopts a continuous process, and the above reaction unit realizes automation, so as to achieve the above-mentioned reaction conditions to be stable, and then the obtained 2-nitro-2-methyl-1-propanol product quality is stable and uniform, and the purity is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0025] Figure 1 A schematic diagram of a continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol according to the present application is shown;

[0026] Figure 2 A schematic diagram of a fixed bed reactor of the present application is shown;

[0027] Figure 3 A schematic diagram of a fixed bed formaldehyde removal device of the present application is shown;

[0028] Figure 4 A schematic top view of the bed layer in the fixed bed formaldehyde removal device of the present application is shown.

[0029] Among them, the above drawings include the following reference numerals:

[0030] 1. First continuous reaction module; 2. Second continuous reaction module; 3. Third continuous reaction module; 4. First gas-liquid separation module; 5. First distillation treatment module; 6. Continuous formaldehyde removal module; 7. Second distillation treatment module; 8. Second gas-liquid separation module; 9. Third distillation treatment module; 10. First continuous module; 20. Second continuous module; 30. Third continuous module; 01. Fixed bed reaction device; 02. Catalytic unit; 03. Catalyst bed; 04. Material bed; 05. Formaldehyde removal catalyst bed. DETAILED DESCRIPTION

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] As analyzed in the background technology of the present application, the intermittent process for producing 2-amino-2-methyl-1-propanol in the prior art has the problems of low production efficiency and yield, poor catalyst selectivity and large dosage requirement, and high formaldehyde residue. In order to solve the above problems, the present application provides a continuous reaction system and a continuous method for producing 2-amino-2-methyl-1-propanol.

[0033] In a typical embodiment of the present application, a continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol is provided, such as Figure 1As shown, the continuous reaction system includes: a first continuous module 10, a second continuous module 20, and a third continuous module 30. The first continuous module 10 includes a first continuous reaction module 1. The first continuous reaction module 1 includes a first inlet and a first outlet. The first inlet is connected to a first raw material source including a solution A source and a solution B source, respectively. The first continuous reaction module 1 is used to sequentially perform a continuous oximation reaction and a continuous oxidation reaction on the first raw material to obtain a first product system containing 2-nitropropane, wherein the solution A includes acetone, an ammonia source and a first solvent, and the solution B includes hydrogen peroxide and a second solvent; The second continuous module 20 includes a second continuous reaction module 2, the second continuous reaction module 2 includes a second inlet and a second outlet, the second inlet is connected to the solution C source, the solution D source, and the first outlet respectively, and the second continuous reaction module 2 is used to continuously condense the raw materials including the solution C, the solution D and the first product system to obtain a second product system containing 2-nitro-2-methyl-1-propanol, wherein the solution C includes formaldehyde and a third solvent, and the solution D includes an alkaline substance and a fourth solvent; the third continuous module 30 includes a third continuous reaction module 3, and the third continuous reaction module 3 includes The third inlet and the third outlet, the third inlet is connected to the raw material source including the solution E source and the hydrogen source respectively, the solution E source enters the third continuous reaction module 3 through the third inlet after coming out of the second outlet, the third continuous reaction module 3 is used to continuously hydrogenate the raw material including the solution E and the hydrogen to obtain a third product system containing 2-amino-2-methyl-1-propanol, wherein the solution E includes the 2-nitro-2-methyl-1-propanol and the fifth solvent in the second product system containing 2-nitro-2-methyl-1-propanol; wherein the first continuous reaction module 1 includes: a fixed bed reaction Device 01, which includes M fixed bed reactors, each fixed bed reactor is provided with N interconnected catalytic units 02, 1≤M, 1≤N, M and N are not 1 at the same time, each fixed bed reactor is provided with a feed port and a discharge port; each catalytic unit 02 independently includes a catalyst bed layer and a material bed layer that are interconnected, the material bed layer is between two adjacent catalyst beds, and each material bed layer has a solution B inlet; solution B is respectively introduced into the catalytic unit 02 from each solution B inlet and the feed port of the fixed bed reactor, and solution A is simultaneously introduced into the feed port of the fixed bed reactor.

[0034] The present invention provides a continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol with high efficiency and low investment, wherein each fixed bed reactor included in the fixed bed reaction device 01 has a large heat exchange area, can quickly remove reaction heat, realize accurate temperature control and high reaction selectivity, and at the same time, the contact interface of the liquid-solid two phases in the fixed bed reactor is large, and the reaction rate is fast, so that the process can be easily scaled up. In the present application, the storage capacity of hydrogen peroxide is small, and hydrogen peroxide is simultaneously introduced through the feed port of the fixed bed reactor and the solution B inlet of the material bed layer, so that multi-point feeding can be realized in the fixed bed reaction device 01, so that hydrogen peroxide is not easy to decompose, and the utilization rate of hydrogen peroxide is improved, while better heat transfer efficiency can be achieved, thereby avoiding the problem that the use of hydrogen peroxide for oxidation reaction in intermittent reaction is not only dangerous and highly exothermic, but also hydrogen peroxide is easy to decompose at high temperature, resulting in low utilization rate; thereby effectively reducing transportation risks and reducing costs. The raw materials including solution C, solution D and the first product system can be fully mixed by the second continuous module 20, so as to avoid the deterioration of the intermediate, and then improve the reaction yield, while avoiding the reaction system when there is uneven local material step or temperature control is not stable, causing the reaction product 2-nitro-2-methyl-1-propanol to decompose back to 2-nitropropane and formaldehyde under the action of a strong base. By the third continuous module 30, the raw materials including solution E, hydrogen and the second product system are subjected to continuous hydrogenation reaction, and the selectivity of 2-nitro-2-methyl-1-propanol can be further improved compared to the batch process, thereby reducing the reaction pressure. The above-mentioned solvent of the present invention is easy to recover, has a higher utilization rate, so as to effectively reduce costs. The present invention adopts a continuous process, and the above reaction unit realizes automation, so as to achieve the above-mentioned reaction conditions to be stable, and then the obtained 2-nitro-2-methyl-1-propanol product quality is stable and uniform, and the purity is higher.

[0035] In one embodiment of the present application, M fixed bed reactors are arranged in series, 1≤M≤10; and / or, the catalyst beds in each catalytic unit 02 are arranged in series, the catalyst beds are arranged in stages, and the catalyst beds are 1 to 10 stages; and / or, the number of solution B inlets in each catalytic unit 02 is 1 to 9.

[0036] Preferably, the fixed bed reactor and the catalyst bed are arranged in series, and the number of catalyst beds is controlled within the above range, which helps to increase the heat exchange area of ​​the fixed bed reactor, thereby quickly removing the reaction heat, thereby increasing the reaction rate and reaction selectivity of the oximation reaction and the oxidation reaction, and facilitating process scale-up. Preferably, the number of solution B inlets in each catalytic unit 02 is within the above range, which helps to introduce hydrogen peroxide into the fixed bed reaction device 01 at multiple points, thereby improving the utilization rate of hydrogen peroxide.

[0037] In order to further improve the utilization rate of hydrogen peroxide, improve the reaction rate and reaction selectivity of oximation reaction and oxidation reaction, in one embodiment of the present application, 3≤M≤6; and / or, the catalyst bed is 3~6 levels, and the number of solution B inlets in each catalytic unit 02 is 2~5.

[0038] In one embodiment of the present application, the first continuous module 10 also includes a first gas-liquid separation module 4 and a first distillation treatment module 5, which are sequentially arranged on the connecting pipeline between the first continuous module 10 and the second continuous module 20; the first gas-liquid separation module 4 is used to perform a first continuous gas-liquid separation treatment on the first product system to obtain a degassed product system and gas impurities; the first distillation treatment module 5 is used to perform a first distillation treatment on the degassed product system to obtain 2-nitropropane and acetone oxime; and / or, the temperature of the first continuous reaction module 1 is controlled by jacket temperature control, the preheating temperature of the first continuous reaction module 1 is 30~60℃, and the insulation temperature of the first continuous reaction module 1 is 50~80℃; and / or, the pressure of the first continuous reaction module 1 is 0.5~10MPa.

[0039] For the separation of the byproduct acetone oxime in the first product system, the present application preferably uses the first gas-liquid separation module 4 and the first distillation treatment module 5, which is helpful for the efficient separation of 2-nitropropane and acetone oxime, thereby avoiding as much as possible the use of external organic solvents to extract and concentrate the reaction solution for separation of each component and the high energy consumption, long time consumption and low efficiency of intermittent distillation. It is preferred to control the temperature of the first continuous reaction module 1 by means of jacket temperature control, and control the preheating temperature and insulation temperature of the first continuous reaction module 1 within the above range, which helps the first continuous reaction module 1 to perform multi-stage temperature control, thereby achieving precise temperature control while reducing the pressure of the first continuous reaction module 1, thereby improving the reaction selectivity.

[0040] In one embodiment of the present application, the second continuous module 20 also includes a continuous formaldehyde removal module 6 and a second distillation treatment module 7, which are sequentially arranged on the connecting pipeline between the second continuous module 20 and the third continuous module 30; the continuous formaldehyde removal module 6 is used to perform continuous formaldehyde removal treatment on the second product system to obtain a product system and gas impurities after formaldehyde removal; the second distillation treatment module 7 is used to perform a second distillation treatment on the product system after formaldehyde removal to obtain 2-nitro-2-methyl-1-propanol; and / or, the second continuous reaction module 2 is a plug flow reactor; the temperature of the second continuous reaction module 2 is controlled by a jacket temperature control method, the preheating temperature of the second continuous reaction module 2 is 20~50℃, and the insulation temperature of the second continuous reaction module 2 is 20~60℃; and / or, the continuous formaldehyde removal module 6 is a fixed bed formaldehyde removal tower, and the tower body, top and bottom top of the fixed bed formaldehyde removal tower are sequentially provided with a feed inlet, The top discharge port and the bottom discharge port are arranged, and the number of feed ports is 1 to 5; the fixed bed aldehyde removal tower has a first inner tower wall and a second inner tower wall relative to each other, and a plurality of aldehyde removal catalyst beds arranged at intervals and interconnected are sequentially arranged along the direction of material flow in the fixed bed aldehyde removal tower, and there is a gap between any two adjacent aldehyde removal catalyst beds and the first inner tower wall and the second inner tower wall respectively, and the gap is used for the circulation of the second product system; and / or the aldehyde removal catalyst beds are 10 to 50 levels; and / or each aldehyde removal catalyst bed is filled with catalyst B, and catalyst B is methylal resin and / or sulfonic acid resin; and / or, the area of ​​the radial cross-section of the fixed bed aldehyde removal tower is S1, and the projected area of ​​each aldehyde removal catalyst bed projected on the radial cross-section of the fixed bed aldehyde removal tower is S2, S1 / S2>50%; and / or, the temperature of the continuous aldehyde removal module 6 is controlled by jacket temperature control, and the insulation temperature of the continuous aldehyde removal module 6 is 20~60℃.

[0041] By using the fixed bed formaldehyde removal device of the above-mentioned continuous formaldehyde removal module 6 and using the above-mentioned catalyst B to remove the residual formaldehyde in the second product system, and setting a multi-stage bed layer and setting the above number of feed ports on the material flow channel, it is helpful to reduce the residual level of formaldehyde to below the 200ppm level, thereby reducing the impact on subsequent reactions. At the same time, the formaldehyde removal catalyst bed and material flow channel on the same horizontal plane control the proportion of the cross-sectional area of ​​the material flow channel to the total cross-sectional area of ​​the fixed bed formaldehyde removal device in the above range, which not only helps the circulation of materials, but also enables the material to be fully contacted with the catalyst B, thereby further improving the efficiency and effect of formaldehyde removal. The temperature of the continuous formaldehyde removal module 6 is controlled by the jacket temperature control method for multi-stage temperature control, and the insulation temperature of the continuous formaldehyde removal module 6 is controlled in the above range, which helps to improve the formaldehyde removal effect of the catalyst B. Since the principle of removing formaldehyde in the continuous aldehyde removal module 6 is to make formaldehyde and alcohol compounds undergo condensation reaction to obtain acetal compounds, when the alcohol solvent is not used in this reaction stage, the second product system needs to be supplemented with an alcohol solvent before the continuous aldehyde removal module 6, and then enter the continuous aldehyde removal module 6 for continuous aldehyde removal treatment. The second rectification treatment module 7 is used to carry out the second rectification treatment on the product system after aldehyde removal, which helps to improve the purity of 2-nitro-2-methyl-1-propanol. At the same time, controlling the preheating temperature and the insulation temperature of the second continuous reaction module 2 in the above range helps to improve the reaction efficiency of the condensation reaction.

[0042] In one embodiment of the present application, the third continuous module 30 also includes a second gas-liquid separation module 8, a third distillation treatment module 9 and a product continuous receiving module 8, and the second gas-liquid separation module 8 and the third distillation treatment module 9 are sequentially arranged on the connecting pipeline between the third continuous module 30 and the product continuous receiving module; the second gas-liquid separation module 8 is used to perform continuous gas-liquid separation treatment on the third product system to obtain a third degassed product system and gas impurities; the third distillation treatment module 9 is used to perform a third distillation treatment on the third degassed product system to obtain 2-amino-2-methyl-1-propanol; and / or, the temperature of the third continuous reaction module 3 is controlled by jacket temperature control, the preheating temperature of the third continuous reaction module 3 is 20~50°C, the insulation temperature of the third continuous reaction module 3 is 30~100°C, and / or, the pressure of hydrogen in the third continuous reaction module 3 is 0.5~4.0MPa.

[0043] The second gas-liquid separation module 8 and the third distillation treatment module 9 are used to perform continuous gas-liquid separation treatment and the third distillation treatment in sequence, and the preheating temperature, the insulation temperature and the pressure of hydrogen in the third continuous reaction module 3 are preferably controlled within the above ranges, which helps to further improve the selectivity of 2-nitro-2-methyl-1-propanol and ensure the stable uniformity and high purity of its quality.

[0044] In another typical embodiment of the present application, a continuous method for preparing 2-nitro-2-methyl-1-propanol using the above-mentioned continuous reaction system is provided, and the continuous method comprises: step S1, sequentially subjecting a first raw material comprising acetone, an ammonia source, hydrogen peroxide, a first solvent and a second solvent to an oximation reaction and an oxidation reaction with a catalyst A to obtain a first product system containing 2-nitropropane; step S2, subjecting a second raw material comprising 2-nitropropane, formaldehyde, an alkaline substance, a third solvent and a fourth solvent to a condensation reaction to obtain a second product system containing 2-nitro-2-methyl-1-propanol; step S3, subjecting a third raw material comprising 2-nitro-2-methyl-1-propanol, hydrogen and a fifth solvent to a hydrogenation reaction with a catalyst C to obtain a third product system containing 2-amino-2-methyl-1-propanol.

[0045] The continuous method for preparing 2-nitro-2-methyl-1-propanol in the present application, not only reaction process is simple, cost is low, and production efficiency is high. The first raw material, under the effect of catalyst A, can fully carry out oximation reaction and oxidation reaction, so as to improve reaction efficiency. In step S2, 2-nitropropane, under the effect of alkaline substance, is easy to condensation reaction with formaldehyde, so as to generate 2-nitro-2-methyl-1-propanol. In step S3, hydrogen is passed through, and the third raw material, under the effect of catalyst B, can improve the efficiency of hydrogenation reaction, so as to improve the productive rate of 2-amino-2-methyl-1-propanol.

[0046] In one embodiment of the present application, the above-mentioned step S1 also includes: step S11, mixing the raw materials including acetone, an ammonia source and a first solvent to obtain solution A; step S12, mixing the raw materials including hydrogen peroxide and a second solvent to obtain solution B; step S13, sequentially performing an oximation reaction and an oxidation reaction on the first raw material including solution A and solution B and catalyst A to obtain a first product system; step S14, sequentially performing a first continuous gas-liquid separation treatment and a first distillation treatment on the first product system to obtain 2-nitropropane and acetone oxime; wherein the molar ratio of acetone to the ammonia source is 1:1~1:10, and the ratio of the mass of acetone to the volume of the first solvent is 1:1~1:20g / mL; and / or, the molar ratio of acetone to hydrogen peroxide is 1:1~1:10; and / or, catalyst A is a spherical titanium oxide silicon molecular sieve with a particle size of 3~5mm, and / or, the loading amount of catalyst A is 10~80% of the volume of the fixed bed reaction device 01 ; and / or, the first solvent and the second solvent are each independently selected from any one or more of methanol, ethanol, n-butanol, isobutanol, tert-butanol, isopropanol, ethylene glycol, water, N,N-dimethylacetamide, dimethyl sulfoxide, ethyl acetate and isopropyl acetate; and / or, the ammonia source is selected from any one or more of ammonia gas, liquid ammonia, ammonia water and an organic ammonia solution; wherein the mass content of ammonia water is 5-40%; the mass content of ammonia gas in the organic ammonia solution is 2-50%, and / or, the organic solvent in the organic ammonia solution is selected from any one or more of methanol, ethanol and ethyl acetate; and / or, the total reaction time of the oximation reaction and the oxidation reaction is 5-100 min; the reaction temperatures of the oximation reaction and the oxidation reaction are each independently 30-100° C.; the reaction pressures of the oximation reaction and the oxidation reaction are each independently 0.5-6.0 MPa; the temperature of the first continuous gas-liquid separation treatment is 15-25° C., and the temperature of the first distillation treatment is 25-80° C.

[0047] It is preferred to control the molar ratio of acetone to ammonia source, the ratio of the mass of acetone to the volume of the first solvent, the molar ratio of acetone to hydrogen peroxide, the type and loading amount of catalyst A, and the total reaction time and temperature of oximation reaction and oxidation reaction within the above range, which is helpful for acetone, ammonia source and hydrogen peroxide to obtain 2-nitropropane through acetone oxime intermediate under the action of catalyst A, thereby achieving control of the amount of catalyst A while improving the reaction efficiency of oximation reaction and oxidation reaction. It is preferred to control the temperature of the first continuous gas-liquid separation treatment within the above range, which is helpful for separating the residual ammonia in the first product system or the oxygen generated by the decomposition of hydrogen peroxide in the reaction, thereby facilitating the subsequent first distillation treatment. It is preferred that the temperature of the first distillation treatment is within the above range, which is helpful for further separation and purification of the obtained 2-nitropropane to enter the next step of reaction, and the separated acetone oxime byproduct can be used for other production activities.

[0048] In one embodiment of the present application, the above-mentioned step S2 also includes: step S21, mixing the raw materials including formaldehyde and the third solvent to obtain solution C; step S22, mixing the raw materials including the alkaline substance and the fourth solvent to obtain solution D; step S23, condensing the second raw material including 2-nitropropane, solution C, and solution D to obtain a second product system; step S24, sequentially performing continuous formaldehyde removal treatment and second distillation treatment on the second product system to obtain 2-nitro-2-methyl-1-propanol; wherein the alkaline substance is an organic alkaline substance and / or an inorganic alkaline substance, and / or the organic alkaline substance is selected from any one or more of trimethylamine, triethylamine, N,N-diisopropylethylamine, N,N,N',N'-tetramethylethylenediamine, 1,8-diazabicycloundec-7-ene, pyridine, N-methyltetrahydropyrrole and triethylenediamine; and / or the inorganic alkaline substance is selected from any one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, carbonate any one or more of potassium, potassium phosphate, potassium acetate and potassium tert-butoxide; and / or the source material of formaldehyde is paraformaldehyde and / or formaldehyde aqueous solution; wherein the mass content of formaldehyde aqueous solution is 5-40%; and / or the molar ratio of 2-nitropropane to alkaline substance is 1:0.001-1:0.5, and the molar ratio of 2-nitropropane to formaldehyde is 1:1-1:5; and / or the third solvent and the fourth solvent are each independently selected from methanol, ethanol, n-butanol, isobutanol, tert-butanol, isobutyl alcohol, Any one or more of propanol, ethylene glycol, water, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, N-methylpyrrole, ethyl acetate, isopropyl acetate and butyl acetate; and / or, the reaction temperature of the condensation reaction is 20-80°C, and the reaction time of the condensation reaction is 10-30min; and / or, the temperature of the second distillation treatment is 40-80°C; the temperature of the continuous formaldehyde removal treatment is 20-60°C, and the time of the continuous formaldehyde removal treatment is 10-60min.

[0049] Preferably, the molar ratio of 2-nitropropane to the alkaline substance, the molar ratio of 2-nitropropane to formaldehyde, the types of formaldehyde and the alkaline substance, and the reaction temperature and reaction time of the condensation reaction are controlled within the above range, which helps 2-nitropropane to fully react with formaldehyde under the action of the alkaline substance to generate 2-nitro-2-methyl-1-propanol. Preferably, the temperature and time of the continuous formaldehyde removal treatment are controlled within the above range, which helps to fully remove formaldehyde in the second product system. Preferably, the temperature of the second distillation treatment is controlled within the above range, which helps to further separate and purify to obtain 2-nitro-2-methyl-1-propanol.

[0050] In one embodiment of the present application, the above step S3 also includes: step S31, mixing the raw materials including 2-nitro-2-methyl-1-propanol and the fifth solvent to obtain solution E; step S32, hydrogenating the third raw material including solution E and hydrogen with catalyst C to obtain a third product system; step S33, sequentially performing a second continuous gas-liquid separation treatment and a third distillation treatment on the third product system to obtain 2-nitro-2-methyl-1-propanol; wherein 2-nitro-2-methyl-1-propanol and the fifth solvent is 1:0.5~1:20, the fifth solvent is selected from any one or more of benzene, toluene, methanol, ethanol, dichloromethane, tetrahydrofuran and N,N-dimethylformamide; and / or the ratio of the molar amount of hydrogen to the molar amount of solution E is 3:1~10:1; and / or the reaction time of the hydrogenation reaction is 10~60min, and the reaction pressure of the hydrogenation reaction is 0.5~3.0MPa; and / or the temperature of the second continuous gas-liquid separation treatment is 15~40°C, and the temperature of the third distillation treatment is 40~130°C.

[0051] Preferably, the mass ratio of 2-nitro-2-methyl-1-propanol and the fifth solvent, the ratio of the molar amount of hydrogen to the molar amount of 2-nitro-2-methyl-1-propanol and solution E, the reaction time and pressure of the hydrogenation reaction are controlled within the above range, which helps 2-nitro-2-methyl-1-propanol to react with hydrogen under the action of a catalyst, thereby improving the yield of the target product 2-amino-2-methyl-1-propanol. Preferably, the temperature of the second continuous gas-liquid separation treatment is controlled within the above range, which helps to separate the gas-liquid product in the third product system. Preferably, the temperature of the third distillation treatment is controlled within the above range, which helps to collect the liquid phase product after gas-liquid separation, and remove the above solvent and by-products, thereby improving the quality of 2-amino-2-methyl-1-propanol.

[0052] The beneficial effects of the present application will be further illustrated below in conjunction with embodiments.

[0053] Example 1

[0054] Use Figure 1 The continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol shown in Figure 2 The fixed bed reactor shown and Figure 3 and Figure 4The fixed bed formaldehyde removal device shown prepares 2-amino-2-methyl-1-propanol, specifically: in the first continuous module 10, solution A is prepared: in a batching kettle, 5.16 mol acetone and 1.15 eq ammonia water are dissolved in 750 mL methanol to obtain solution A, which is placed in a liquid storage tank A; solution B is prepared: in a batching kettle, 2.0 eq hydrogen peroxide is dissolved in 1500 mL methanol to obtain solution B, which is placed in a liquid storage tank B; the fixed bed reactor and the preheater in the first continuous reaction module 1 are heated by jacket temperature control, and the temperatures are set to 60°C and 40°C, respectively; the back pressure valve of the fixed bed reactor is adjusted to ensure that the pressure in the fixed bed reactor is constant at 4-5 MPa, and when the preheating temperature in the preheater is 40°C and the insulation temperature of the fixed bed reactor is 60°C, the feed pumps of the liquid storage tank A and the liquid storage tank B are turned on at the same time, and the feed amounts are set to 12.6 g / min and 23.4 g / min, respectively. The fixed bed reaction device 01 includes three fixed bed reactors arranged in series, each fixed bed reactor is provided with three interconnected catalytic units 02, the catalyst beds in each catalytic unit 02 are arranged in series, each catalytic unit 02 independently includes a catalyst bed 03 and a material bed 04 which are interconnected, and the catalyst bed 03 is three-stage; the number of the solution B inlet in each catalytic unit 02 is three. Solution B is introduced into the catalytic unit 02 from each solution B inlet and the feed port of the fixed bed reactor respectively, and solution A is introduced into the feed port of the fixed bed reactor at the same time, the first raw materials of solution A and solution B are preheated in a preheater and fully mixed with a spherical titanium oxide silicon molecular sieve catalyst A with a particle size of 3 mm in the fixed bed reactor, and continuous oximation reaction and oxidation reaction are carried out in sequence to obtain a first product system containing 2-nitropropane, wherein the loading amount of catalyst A is 75% of the volume of the fixed bed reaction device 01, and the total reaction time of oximation reaction and oxidation reaction is 5 min; the reaction temperature of oximation reaction and oxidation reaction is 200 °C. The temperature is independently 100° C., and the reaction pressure is independently 6.0 MPa; the first product system containing 2-nitropropane is output from the first outlet of the first continuous reaction module 1, enters the first gas-liquid separation module 4 for the first continuous gas-liquid separation treatment, and the obtained degassed product system and gas impurities enter the first distillation treatment module 5 for the first distillation treatment to obtain 2-nitropropane and acetone oxime, acetone oxime enters the intermediate storage tank, and 2-nitropropane enters the second continuous reaction module 2 through the second inlet, wherein the temperature of the first continuous gas-liquid separation treatment is 20° C., and the temperature of the first distillation treatment is 30° C.

[0055] Solution C is prepared in the second continuous module 20: in a liquid storage tank C, a 37% formaldehyde aqueous solution and methanol are stirred and dissolved, the molar ratio of formaldehyde to 2-nitropropane is 1:1, and the ratio of the volume of methanol to the mass of 2-nitropropane is 0.3 mL / g; solution D is prepared: in a liquid storage tank D, triethylamine and methanol are stirred and dissolved, the molar ratio of triethylamine to 2-nitropropane is 0.02:1, and the ratio of the volume of methanol to the mass of 2-nitropropane is 0.2 mL / g; the second continuous reaction module 2 is a plug flow reactor, and the temperature of the second continuous reaction module 2 is controlled by jacket temperature control. The preheating temperature of the second continuous reaction module 2 is 40°C, and the insulation temperature is 50°C. The feed pumps of storage tanks C and D are turned on, and the feed flow rates of solution C and solution D are set to 2.66 g / min and 2.3 g / min, respectively. 2-nitropropane, solution C and solution D are subjected to continuous condensation reaction in the second continuous reaction module 2, the reaction temperature of the condensation reaction is 20°C, the reaction time is 30min, and the second product system containing 2-nitro-2-methyl-1-propanol is obtained, and then enters the continuous aldehyde removal module 6 for continuous aldehyde removal treatment to obtain a product system after aldehyde removal and gas impurities, wherein the continuous aldehyde removal module 6 is a fixed bed aldehyde removal device, the fixed bed aldehyde removal device comprises an aldehyde removal catalyst bed 05 and a material flow channel which are sequentially connected and arranged, the number of feed ports on the material flow channel is 3, the aldehyde removal catalyst bed 05 is graded, and the aldehyde removal catalyst bed 05 has 30 grades; Figure 4 As shown, the catalyst bed 05 and the material flow channel of the same horizontal plane, the cross-sectional area of ​​the material flow channel accounts for 50% of the total cross-sectional area of ​​the fixed bed formaldehyde removal device. The fixed bed formaldehyde removal device is filled with catalyst B methylal resin, and the temperature of the continuous formaldehyde removal treatment is controlled at 45~50℃ for 30min. The product system after formaldehyde removal is discharged from the top discharge port of the fixed bed formaldehyde removal device and enters the second distillation treatment module 7 for the second distillation treatment to obtain 2-nitro-2-methyl-1-propanol. The temperature of the second distillation treatment is 40℃. The impurities after formaldehyde removal in the second product system are discharged from the bottom discharge port of the fixed bed formaldehyde removal device and then subjected to three waste treatment.

[0056] Solution E is prepared in the third continuous module 30: in the batching kettle, 2-nitro-2-methyl-1-propanol output from the second distillation treatment module 7 is dissolved in methanol to prepare a methanol solution of 2-nitro-2-methyl-1-propanol with a mass fraction of 10%, and the prepared solution is placed in the liquid storage tank E. After the air tightness test of the reaction system is qualified, nitrogen and hydrogen are replaced. After completion, the third continuous reaction module 3 and the second gas-liquid separation module 8 are heated, and the temperatures are set to 40°C and 30°C respectively. The feed pump of the liquid storage tank E is turned on, and the feed flow rate is set to 1.0g / min; the flow rate of hydrogen is 100mL / min, and the pressure of hydrogen is 2.0MPa. Solution E is fully mixed with hydrogen through the distributor above the third continuous reaction module 3, and the gas-liquid mixture enters the catalyst bed and undergoes hydrogenation reaction in a catalyst palladium carbon with a mass content of 5%, to obtain a third product system containing 2-amino-2-methyl-1-propanol, which is output from the third outlet and enters the second gas-liquid separation module 8 for gas-liquid separation to obtain a third degassing product system and gas impurities. The third degassing product system enters the third distillation treatment module 9 for a third distillation treatment to obtain 2-amino-2-methyl-1-propanol, wherein the preheating temperature of the third continuous reaction module 3 is 30°C, the insulation temperature is 40°C, the reaction time of the hydrogenation reaction is 30min, and the reaction pressure of the hydrogenation reaction is 2.0MPa.

[0057] Example 2

[0058] The difference from Example 1 is that the molar ratio of acetone to aqueous ammonia in solution A is 1:2, and 2-amino-2-methyl-1-propanol is finally obtained.

[0059] Example 3

[0060] The difference from Example 1 is that 2.0 eq of hydrogen peroxide is dissolved in 500 mL of methanol to obtain solution B, and finally 2-amino-2-methyl-1-propanol is obtained.

[0061] Example 4

[0062] The difference from Example 1 is that the insulation temperature of the first continuous reaction module 1 is 70° C., and 2-amino-2-methyl-1-propanol is finally obtained.

[0063] Example 5

[0064] The difference from Example 1 is that the insulation temperature of the first continuous reaction module 1 is 50° C., and 2-amino-2-methyl-1-propanol is finally obtained.

[0065] Example 6

[0066] The difference from Example 1 is that the pressure of the first continuous reaction module 1 is constant at 2-3 MPa, and 2-amino-2-methyl-1-propanol is finally obtained.

[0067] Example 7

[0068] The difference from Example 1 is that the pressure of the first continuous reaction module 1 is constant at 5-6 MPa, and 2-amino-2-methyl-1-propanol is finally obtained.

[0069] Example 8

[0070] The difference from Example 1 is that solution D is prepared by stirring sodium hydroxide and methanol to dissolve, the molar ratio of sodium hydroxide to 2-nitropropane is 0.02:1, the volume ratio of methanol to the mass ratio of 2-nitropropane is 0.2 mL / g, and finally 2-amino-2-methyl-1-propanol is obtained.

[0071] Comparative Example 1

[0072] The difference from Example 1 is that 5.16mol of acetone, 1.15eq of ammonia and 2.0eq of hydrogen peroxide and titanium oxide silicon molecular sieve are added to a reactor, and the ammonia and hydrogen peroxide addition time is 1h, and the reaction is kept warm for 10h after the dropwise addition is completed. Reaction is rectified after completion to obtain 2-nitropropane. 2-nitropropane and 37% formaldehyde aqueous solution, 0.02eq triethylamine, and methanol are added to a reactor with a mass content of 2-nitropropane. The volume of methanol and the mass ratio of 2-nitropropane are 0.5mL / g, and the reaction is kept warm for 4 hours and rectified to obtain 2-nitro-2-methyl-1-propanol. After intermediate 2-nitro-2-methyl-1-propanol, methanol and catalyst palladium carbon are added to the reactor, sealed, and then hydrogen is passed through to make the pressure reach 2.0MPa, and the reaction is kept warm for 2h, and rectified after cooling to room temperature to obtain 2-amino-2-methyl-1-propanol.

[0073] Test Method

[0074] The conversion rate, selectivity and yield of the above products in the above examples and comparative examples as well as the residual formaldehyde content of the second product system after continuous formaldehyde removal treatment were tested. The test results are shown in Table 1.

[0075] Table 1

[0076]

[0077] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0078] The present invention provides a continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol with high efficiency and low investment, wherein each fixed bed reactor included in the fixed bed reaction device has a large heat exchange area, can quickly remove reaction heat, realize accurate temperature control and high reaction selectivity, and at the same time, the contact interface of the liquid-solid two phases in the fixed bed reactor is large, and the reaction rate is fast, so that the process can be easily amplified. In the present application, the storage capacity of hydrogen peroxide is small, and hydrogen peroxide is simultaneously introduced through the feed port of the fixed bed reactor and the solution B inlet of the material bed layer, so that multi-point feeding can be realized in the fixed bed reaction device, so that hydrogen peroxide is not easy to decompose, and the utilization rate of hydrogen peroxide is improved, while better heat transfer efficiency can be achieved, thereby avoiding the problem that the use of hydrogen peroxide for oxidation reaction in intermittent reaction is not only dangerous and highly exothermic, but also hydrogen peroxide is easy to decompose at high temperature, resulting in low utilization rate; thereby effectively reducing transportation danger and reducing costs. The raw materials including solution C, solution D and the first product system can be fully mixed by the second continuous module, so as to avoid the deterioration of the intermediate, and then improve the reaction yield, while avoiding the reaction system when there is uneven local material step or temperature control is not stable, causing the reaction product 2-nitro-2-methyl-1-propanol to decompose back to 2-nitropropane and formaldehyde under the action of a strong base. By the third continuous module, the raw materials including solution E, hydrogen and the second product system are continuously hydrogenated, and the selectivity of 2-nitro-2-methyl-1-propanol can be further improved compared to batch process, so as to reduce the reaction pressure. The above-mentioned solvent of the present invention is easy to recover, has a higher utilization rate, so as to effectively reduce costs. The present invention adopts a continuous process, and the above reaction unit realizes automation, so as to achieve the above-mentioned reaction conditions to be stable, and then the obtained 2-nitro-2-methyl-1-propanol product quality is stable and uniform, and the purity is higher.

[0079] The above are only embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A continuous reaction system for continuously producing 2-amino-2-methyl-1-propanol, characterized in that: The continuous reaction system comprises: The first continuous module (10) comprises a first continuous reaction module (1), wherein the first continuous reaction module (1) comprises a first inlet and a first outlet, wherein the first inlet is respectively connected to a first raw material source comprising a solution A source and a solution B source, and the first continuous reaction module (1) is used to sequentially perform a continuous oximation reaction and a continuous oxidation reaction on the first raw material to obtain a first product system containing 2-nitropropane, wherein the solution A comprises acetone, an ammonia source and a first solvent, and the solution B comprises hydrogen peroxide and a second solvent; The second continuous module (20) comprises a second continuous reaction module (2), wherein the second continuous reaction module (2) comprises a second inlet and a second outlet, wherein the second inlet is connected to a solution C source, a solution D source, and the first outlet, respectively, and the second continuous reaction module (2) is used to perform a continuous condensation reaction on raw materials including solution C, solution D, and the first product system to obtain a second product system containing 2-nitro-2-methyl-1-propanol, wherein the solution C comprises formaldehyde and a third solvent, and the solution D comprises an alkaline substance and a fourth solvent; The third continuous module (30) comprises a third continuous reaction module (3), wherein the third continuous reaction module (3) comprises a third inlet and a third outlet, wherein the third inlet is respectively connected to a raw material source comprising a solution E source and a hydrogen source, wherein the solution E source enters the third continuous reaction module (3) through the third inlet after exiting from the second outlet, and the third continuous reaction module (3) is used to perform a continuous hydrogenation reaction on the raw material comprising the solution E and the hydrogen to obtain a third product system containing 2-amino-2-methyl-1-propanol, wherein the solution E comprises the second product system and a fifth solvent; Wherein, the first continuous reaction module (1) comprises: A fixed bed reaction device (01), comprising M fixed bed reactors, each of which is provided with N interconnected catalytic units (02), 1≤M, 1≤N, M and N are not 1 at the same time, and each of the fixed bed reactors is provided with a feed inlet and a discharge port; Each of the catalytic units (02) independently comprises a catalyst bed and a material bed which are interconnected, the material bed being located between two adjacent catalyst beds, and each of the material beds having an inlet for solution B; the solution B is introduced into the catalytic unit (02) from each of the solution B inlets and the feed port of the fixed bed reactor, and the solution A is simultaneously introduced into the feed port of the fixed bed reactor.

2. The continuous reaction system according to claim 1, characterized in that: The M fixed bed reactors are arranged in series, 1≤M≤10; and / or, the catalyst beds in each of the catalytic units (02) are arranged in series, the catalyst beds are arranged in stages, and the catalyst beds are of 1 to 10 stages; and / or, the number of the solution B inlet in each of the catalytic units (02) is 1 to 9.

3. The continuous reaction system according to claim 2, characterized in that: 3≤M≤6; and / or, the catalyst bed has 3 to 6 levels, and the number of the solution B inlet in each of the catalytic units (02) is 2 to 5.

4. The continuous reaction system according to any one of claims 1 to 3, characterized in that: The first continuous module (10) further comprises a first gas-liquid separation module (4) and a first distillation processing module (5), wherein the first gas-liquid separation module (4) and the first distillation processing module (5) are sequentially arranged on a connecting pipeline between the first continuous module (10) and the second continuous module (20); The first gas-liquid separation module (4) is used to perform a first continuous gas-liquid separation process on the first product system to obtain a degassed product system and gas impurities; The first distillation treatment module (5) is used to perform a first distillation treatment on the degassing product system to obtain 2-nitropropane and acetone oxime; And / or, the temperature of the first continuous reaction module (1) is controlled by means of jacket temperature control, the preheating temperature of the first continuous reaction module (1) is 30-60° C., and the insulation temperature of the first continuous reaction module (1) is 50-80° C.; and / or, the pressure of the first continuous reaction module (1) is 0.5-10 MPa.

5. The continuous reaction system according to any one of claims 1 to 3, characterized in that: The second continuous module (20) further comprises a continuous formaldehyde removal module (6) and a second distillation treatment module (7). The continuous formaldehyde removal module (6) and the second distillation treatment module (7) are sequentially arranged on the connecting pipeline between the second continuous module (20) and the third continuous module (30); The continuous formaldehyde removal module (6) is used to continuously remove formaldehyde from the second product system to obtain a product system and gas impurities after formaldehyde removal; The second distillation treatment module (7) is used to perform a second distillation treatment on the product system after aldehyde removal to obtain 2-nitro-2-methyl-1-propanol; And / or, the second continuous reaction module (2) is a plug flow reactor; the temperature of the second continuous reaction module (2) is controlled by a jacket temperature control method, the preheating temperature of the second continuous reaction module (2) is 20-50° C., and the insulation temperature of the second continuous reaction module (2) is 20-60° C.; And / or, the continuous formaldehyde removal module (6) is a fixed bed formaldehyde removal tower, the tower body, top and bottom of the fixed bed formaldehyde removal tower are sequentially provided with a feed inlet, a top discharge inlet and a bottom discharge inlet, and the number of the feed inlets is 1 to 5; The fixed bed aldehyde removal tower has a first inner tower wall and a second inner tower wall relative to each other, and a plurality of aldehyde removal catalyst beds are sequentially arranged at intervals and interconnected along the direction of material flow in the fixed bed aldehyde removal tower, and there is a gap between any two adjacent aldehyde removal catalyst beds and the first inner tower wall and the second inner tower wall, respectively, and the gap is used for the flow of the second product system; and / or the aldehyde removal catalyst beds are 10 to 50 levels; and / or each of the aldehyde removal catalyst beds is filled with a catalyst B, and the catalyst B is a methylal resin and / or a sulfonic acid resin; and / or, the area of ​​the radial cross section of the fixed bed aldehyde removal tower is S1, the projected area of ​​each aldehyde removal catalyst bed layer projected on the radial cross section of the fixed bed aldehyde removal tower is S2, and S1 / S2>50%; And / or, the temperature of the continuous formaldehyde removal module (6) is controlled by means of jacket temperature control, and the insulation temperature of the continuous formaldehyde removal module (6) is 20-60°C.

6. The continuous reaction system according to any one of claims 1 to 3, characterized in that: The third continuous module (30) further comprises a second gas-liquid separation module (8), a third distillation processing module (9) and a product continuous receiving module (8), wherein the second gas-liquid separation module (8) and the third distillation processing module (9) are sequentially arranged on a connecting pipeline between the third continuous module (30) and the product continuous receiving module; The second gas-liquid separation module (8) is used to perform continuous gas-liquid separation processing on the third product system to obtain a third degassed product system and gas impurities; The third distillation treatment module (9) is used to perform a third distillation treatment on the third degassing product system to obtain 2-amino-2-methyl-1-propanol; And / or, the temperature of the third continuous reaction module (3) is controlled by a jacket temperature control method, the preheating temperature of the third continuous reaction module (3) is 20-50° C., the insulation temperature of the third continuous reaction module (3) is 30-100° C., and / or, the pressure of hydrogen in the third continuous reaction module (3) is 0.5-4.0 MPa.

7. A continuous method for preparing 2-nitro-2-methyl-1-propanol using the continuous reaction system according to any one of claims 1 to 6, characterized in that: The continuous process comprises: Step S1, sequentially subjecting a first raw material including acetone, an ammonia source, hydrogen peroxide, a first solvent and a second solvent to an oximation reaction and an oxidation reaction with a catalyst A to obtain a first product system containing 2-nitropropane; Step S2, subjecting the second raw material including the 2-nitropropane, formaldehyde, an alkaline substance, a third solvent and a fourth solvent to a condensation reaction to obtain a second product system containing 2-nitro-2-methyl-1-propanol; Step S3, subjecting the third raw material including the 2-nitro-2-methyl-1-propanol, hydrogen and the fifth solvent to a hydrogenation reaction with a catalyst C to obtain a third product system containing 2-amino-2-methyl-1-propanol.

8. The continuous process according to claim 7, characterized in that: The step S1 further comprises: Step S11, mixing the raw materials including the acetone, the ammonia source and the first solvent to obtain a solution A; Step S12, mixing the raw materials including the hydrogen peroxide and the second solvent to obtain a solution B; Step S13, subjecting the first raw material including the solution A and the solution B to the catalyst A in sequence for the oximation reaction and the oxidation reaction to obtain the first product system; Step S14, subjecting the first product system to a first continuous gas-liquid separation treatment and a first distillation treatment in sequence to obtain 2-nitropropane and acetone oxime; Wherein, the molar ratio of the acetone to the ammonia source is 1:1-1:10, and the ratio of the mass of the acetone to the volume of the first solvent is 1:1-1:20 g / mL; and / or, the molar ratio of the acetone to the hydrogen peroxide is 1:1-1:10; and / or, the catalyst A is a spherical titanium oxide silicon molecular sieve having a particle size of 3 to 5 mm, and / or, the loading amount of the catalyst A is 10 to 80% of the volume of the fixed bed reaction device (01); and / or, the first solvent and the second solvent are each independently selected from any one or more of methanol, ethanol, n-butanol, isobutanol, tert-butanol, isopropanol, ethylene glycol, water, N,N-dimethylacetamide, dimethyl sulfoxide, ethyl acetate and isopropyl acetate; And / or, the ammonia source is selected from any one or more of ammonia gas, liquid ammonia, ammonia water and an organic ammonia solution; wherein the mass content of the ammonia water is 5-40%; the mass content of ammonia gas in the organic ammonia solution is 2-50%, and / or, the organic solvent in the organic ammonia solution is selected from any one or more of methanol, ethanol and ethyl acetate; And / or, the total reaction time of the oximation reaction and the oxidation reaction is 5 to 100 min; the reaction temperature of the oximation reaction and the oxidation reaction is independently 30 to 100° C.; the reaction pressure of the oximation reaction and the oxidation reaction is independently 0.5 to 6.0 MPa; The temperature of the first continuous gas-liquid separation treatment is 15-25°C, and the temperature of the first distillation treatment is 25-80°C.

9. The continuous process according to claim 8, characterized in that: The step S2 further comprises: Step S21, mixing the raw materials including the formaldehyde and the third solvent to obtain a solution C; Step S22, mixing the raw material including the alkaline substance and the fourth solvent to obtain a solution D; Step S23, subjecting the second raw material including the 2-nitropropane, the solution C, and the solution D to the condensation reaction to obtain the second product system; Step S24, sequentially subjecting the second product system to continuous formaldehyde removal treatment and second distillation treatment to obtain 2-nitro-2-methyl-1-propanol; Wherein, the alkaline substance is an organic alkaline substance and / or an inorganic alkaline substance, and / or the organic alkaline substance is selected from any one or more of trimethylamine, triethylamine, N,N-diisopropylethylamine, N,N,N',N'-tetramethylethylenediamine, 1,8-diazabicycloundec-7-ene, pyridine, N-methyltetrahydropyrrole and triethylenediamine; and / or the inorganic alkaline substance is selected from any one or more of sodium hydroxide, potassium hydroxide, lithium hydroxide, sodium bicarbonate, sodium carbonate, potassium carbonate, potassium phosphate, potassium acetate and potassium tert-butoxide; And / or, the source material of the formaldehyde is paraformaldehyde and / or formaldehyde aqueous solution; wherein the mass content of the formaldehyde aqueous solution is 5-40%; And / or, the molar ratio of the 2-nitropropane to the alkaline substance is 1:0.001 to 1:0.5, and the molar ratio of the 2-nitropropane to the formaldehyde is 1:1 to 1:5; and / or, the third solvent and the fourth solvent are each independently selected from any one or more of methanol, ethanol, n-butanol, isobutanol, tert-butanol, isopropanol, ethylene glycol, water, N,N-dimethylacetamide, dimethyl sulfoxide, tetrahydrofuran, dioxane, N-methylpyrrole, ethyl acetate, isopropyl acetate and butyl acetate; And / or, the reaction temperature of the condensation reaction is 20-80° C., and the reaction time of the condensation reaction is 10-30 min; And / or, the temperature of the second distillation treatment is 40-80°C; The temperature of the continuous formaldehyde removal treatment is 20-60° C., and the time of the continuous formaldehyde removal treatment is 10-60 min.

10. The continuous process according to any one of claims 7 to 9, characterized in that The step S3 further comprises: Step S31, mixing the raw materials including the 2-nitro-2-methyl-1-propanol and the fifth solvent to obtain a solution E; Step S32, subjecting the third raw material including the solution E and the hydrogen to the hydrogenation reaction with the catalyst C to obtain the third product system; Step S33, sequentially subjecting the third product system to a second continuous gas-liquid separation treatment and a third distillation treatment to obtain 2-amino-2-methyl-1-propanol; Wherein, the mass ratio of the 2-nitro-2-methyl-1-propanol to the fifth solvent is 1:0.5 to 1:20, and the fifth solvent is selected from any one or more of benzene, toluene, methanol, ethanol, dichloromethane, tetrahydrofuran and N,N-dimethylformamide; and / or, the ratio of the molar amount of the hydrogen to the molar amount of the solution E is 3:1 to 10:1; And / or, the reaction time of the hydrogenation reaction is 10 to 60 min, and the reaction pressure of the hydrogenation reaction is 0.5 to 3.0 MPa; And / or, the temperature of the second continuous gas-liquid separation treatment is 15-40°C, and the temperature of the third distillation treatment is 40-130°C.

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