A continuous microreactor 4,4'-oxydianiline preparation system

Abstract

The application provides a continuous micro-reactor 4,4'-diamino diphenyl ether preparation system, which comprises a 4,4'-dinitrodiphenyl ether preparation system, a micro-tube reaction system arranged behind the 4,4'-dinitrodiphenyl ether reactant preparation system, and a material collecting system arranged behind the micro-tube reactor. The micro-tube reaction system comprises a micro-tube reactor, a hydrogen inlet and a raw material inlet are arranged on the micro-tube reactor, an inner sleeve and an outer sleeve are arranged on the micro-tube reactor, a material channel is formed between the outer sleeve and the inner sleeve, and the outer sleeve and the inner sleeve are temperature control medium channels. The 4,4'-dinitrodiphenyl ether obtained through the 4,4'-dinitrodiphenyl ether preparation system is introduced into the micro-tube reaction system, hydrogen and 3% palladium-carbon catalyst are continuously added into the micro-tube reactor through the hydrogen inlet and the raw material inlet respectively, the hydrogenation catalytic reduction reaction is realized, and the reaction efficiency is significantly improved through the hydrogenation catalytic reduction reaction in the micro-tube reaction system.

Description

Technical Field

[0001] This invention relates to the field of 4,4'-diaminodiphenyl ether preparation technology, and to a system for preparing 4,4'-diaminodiphenyl ether by hydrogenation, particularly a system for preparing 4,4'-diaminodiphenyl ether by continuous flow hydrogenation using microreaction. Background Technology

[0002] The hydrogenation of 4,4'-dinitrodiphenyl ether to prepare 4,4'-diaminodiphenyl ether involves a gas-solid-liquid three-phase reaction. Specifically, N,N-dimethylacetamide (DMAC) is used as the hydrogenation reduction solvent, and 3% palladium on carbon is used as the hydrogenation catalyst. Hydrogen gas is introduced into the reduction vessel to carry out the hydrogenation reaction. The 4,4'-dinitrodiphenyl ether molecule reacts with the hydrogen atoms adsorbed on the catalyst surface, and the nitro group on the benzene ring is reduced to an amino group. 4,4'-dinitrodiphenyl ether is reduced to 4,4'-diaminodiphenyl ether.

[0003] However, the traditional method for preparing 4,4'-diaminodiphenyl ether involves a hydrogenation catalytic reaction in a reactor, resulting in low reaction efficiency. In order to achieve efficient preparation of 4,4'-diaminodiphenyl ether, a new preparation technology for 4,4'-diaminodiphenyl ether is needed. Summary of the Invention

[0004] In order to improve the preparation efficiency of 4,4'-diaminodiphenyl ether and realize hydrogen recovery in the preparation process of 4,4'-diaminodiphenyl ether, the present invention provides a continuous microreactor 4,4'-diaminodiphenyl ether preparation system.

[0005] The present invention is as follows:

[0006] A continuous microreactor system for preparing 4,4'-diaminodiphenyl ether, comprising:

[0007] 4,4'-Dinitrodiphenyl ether preparation system;

[0008] A microtube reaction system set up after the 4,4'-dinitrodiphenyl ether reactant preparation system.

[0009] A collection system is installed after the microtube reactor.

[0010] The microtube reaction system includes a microtube reactor, which is provided with a hydrogenation port and a raw material inlet for introducing 4,4'-dinitrodiphenyl ether reaction liquid and catalyst;

[0011] The microtube reactor is provided with an inner sleeve and an outer sleeve. The gap between the outer sleeve and the inner sleeve is a material channel, and the outer sleeve and the inner sleeve are a temperature control medium channel.

[0012] In this application, 4,4'-dinitrodiphenyl ether obtained from the 4,4'-dinitrodiphenyl ether preparation system is introduced into a microtube reaction system. Hydrogen and 3% palladium on carbon catalyst are continuously added to the microtube reactor through the hydrogenation port and the feed inlet, respectively, to achieve a hydrogenation catalytic reduction reaction. After the reaction is completed in the microtube reaction system, the 4,4'-diaminodiphenyl ether obtained from the reaction is collected through a collection system.

[0013] Each microchannel of the hydrogenation microtube reactor consists of two sleeves. The inner sleeve is a channel through which cooling water is introduced to cool the reaction system and control the reaction temperature.

[0014] To further control the reaction temperature in the microtube reactor, the microtube reactor system also includes a circulating temperature control medium system for circulating cooling of the microtube reactor. The circulating temperature control medium system includes a hot water tank connected to the inner and outer sleeves, and a soft water tank for replenishing the hot water tank.

[0015] In a preferred embodiment of this application, more specifically, the 4,4'-dinitrodiphenyl ether preparation system includes: a 4,4'-dinitrodiphenyl ether intermediate tank, which is purged with nitrogen gas and equipped with a 4,4'-dinitrodiphenyl ether inlet and an N2 inlet; a feed metering tank located downstream of the 4,4'-dinitrodiphenyl ether intermediate tank; and a mixing vessel located downstream of the feed metering tank, which is purged with nitrogen gas. The feed liquid from the mixing vessel is pumped into a microtube reactor via a metering pump.

[0016] Preferably, the receiving system includes: a material receiving vessel disposed after the microtube reactor; a filter disposed after the material receiving vessel; a concentration vessel disposed after the filter; a cooling crystallization vessel disposed after the concentration vessel; a centrifuge disposed after the cooling crystallization vessel; and a drying receiving device disposed after the centrifuge.

[0017] After hydrogenation catalytic reduction of 4,4'-dinitrodiphenyl ether in a microtube reactor, the resulting crude 4,4'-diaminodiphenyl ether reaction solution enters a material receiving vessel. The catalyst in the crude 4,4'-diaminodiphenyl ether reaction solution is filtered out by a filter, and the filtered catalyst can be recycled. The filtered 4,4'-diaminodiphenyl ether liquid is then sent to a concentration vessel. The concentrated 4,4'-diaminodiphenyl ether is crystallized in a cooling crystallization vessel, and impurities and unreacted substances are further removed by a centrifuge. Finally, the 4,4'-diaminodiphenyl ether is dried and collected in a drying receiving device.

[0018] In order to maintain a constant pressure in the material receiving vessel, a pressure relief system is provided after the material receiving vessel. The pressure relief system includes a pressure relief buffer tank connected to the material receiving vessel, a condenser located after the pressure relief buffer tank, a water seal system located after the condenser, and an evacuation device located after the water seal system.

[0019] In order to recover excess hydrogen in the microreactor and reduce hydrogen waste, a gas-liquid separation device is installed between the microtube reaction system and the receiving system.

[0020] Furthermore, the gas-liquid separation device collects the hydrogen gas remaining from the microtube reactor reaction and then introduces it into the intermittent hydrogenation reactor.

[0021] In another alternative hydrogen recycling scheme, the gas-liquid separation device collects the hydrogen remaining from the microtube reactor reaction and then reintroduces it into the microtube reactor via a booster pump.

[0022] Furthermore, the product filtered by the filter is a catalyst.

[0023] The steam from the hot water tank is used to heat the batching vessel.

[0024] The beneficial effects of this application are as follows:

[0025] 1. In this application, the microtube reactor is provided with an inner sleeve and an outer sleeve. The gap between the outer sleeve and the inner sleeve serves as a material channel, and the outer sleeve and the inner sleeve serve as a temperature-controlled medium channel. Each microchannel of the hydrogenation microtube reactor consists of two sleeves. Water is circulated through the inner sleeve and the outer sleeve to control the reaction temperature of the reaction system. In this embodiment, the microtube reactor is specifically configured with an inner sleeve diameter of φ22mm, an outer sleeve diameter of φ32mm, and a sleeve gap of 3mm, thereby forming an annular microchannel.

[0026] The catalyst used in this embodiment is a solid powder palladium-on-carbon catalyst. To prevent the catalyst from clogging the microchannels of the reactor, the catalyst is made of fine particles with an average particle size of 16 μm. The diameter of the micro-reaction channel is 187.5 times that of the catalyst particle size, which can effectively avoid clogging of the microreactor channel. At the same time, the reactor adopts a sleeve-type microtube reactor with a straight tube reaction channel, which avoids the disadvantage of easy clogging of labyrinth-type microchannels.

[0027] 2. The hydrogenation reaction is normally controlled within the range of 110℃-115℃. Since the hydrogenation reaction is exothermic, a certain temperature must be reached in the early stages for the reaction to proceed rapidly. Moreover, if the circulating cooling water flow rate is too high in the later stages, the temperature of the feed liquid can easily drop, slowing down the reaction and resulting in incomplete reaction of the raw materials. Therefore, the circulating temperature control medium system set up in this application consists of a hot water tank, a hot water pump, a soft water tank, and a makeup water pump. Hot water at 75℃-85℃ is used for preheating the reaction feed liquid and controlling the reaction temperature. Through the circulating temperature control medium system, the inlet water temperature of the microreactor can be controlled at 75℃ and the outlet water temperature at 80-85℃. After the circulating temperature control medium is cooled down by the circulating water in the heat exchanger, it returns to the hot water tank, realizing the circulation of hot water and the temperature control of the reactor.

[0028] 3. To recover hydrogen and reduce waste, a gas-liquid separation device is installed between the microtube reactor system and the collection system. This device separates hydrogen from the 4,4'-diaminodiphenyl ether reaction liquid. The remaining hydrogen from the microtube reactor is collected and fed into a batch hydrogenation reactor. The residual hydrogen discharged from the microtube reactor has a high pressure, reaching 1.0 MPa-2.0 MPa, allowing it to be utilized in the batch hydrogenation reactor, thus achieving hydrogen utilization.

[0029] 4. The gas-liquid separation device collects the hydrogen gas remaining from the microtube reactor reaction and then reintroduces it into the microtube reactor through a booster pump. Alternatively, the remaining hydrogen gas can be pressurized by a screw booster pump and then returned to the microtube reactor to continue participating in the reaction. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the continuous microreactor 4,4'-diaminodiphenyl ether preparation system of this application;

[0031] Figure 2 This is a schematic diagram of the hydrogen recovery and utilization system prepared in this application;

[0032] Figure 3 This is a schematic diagram of another hydrogen recovery and utilization method in the preparation system of this application;

[0033] Figure 4 This is a schematic diagram of a microtube reactor according to this application;

[0034] Figure 5 for Figure 4 Enlarged view of A in the middle;

[0035] Figure 6 This is a schematic diagram of another microtube reactor according to this application;

[0036] Figure 7 for Figure 6 Enlarged view of B in the middle;

[0037] In the diagram, 4,4'-dinitrodiphenyl ether intermediate tank 110; liquid metering tank 120; batching kettle 130; metering pump 140;

[0038] Microtube reactor 210; hydrogenation port 211; raw material inlet 213; raw material channel 214; material channel 215; reaction product outlet 216; microporous tube 217; gas-liquid mixing zone 218; inner tube water inlet 221;

[0039] Inner sleeve 222; Inner pipe water outlet 223; Outer pipe water inlet 224; Outer sleeve 225; Outer pipe water outlet 226; Vent 227; Hot water tank 228; Soft water tank 229;

[0040] Material receiving vessel 310; filter 320; concentration vessel 330; cooling crystallization vessel 340; centrifuge 350; drying and receiving device 360;

[0041] Gas-liquid separation device 400; intermittent hydrogenation reactor 401; booster pump 402;

[0042] Pressure relief buffer tank 510; condenser 520; water seal system 530; venting device 540. Detailed Implementation

[0043] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Example 1

[0045] like Figure 1 A continuous microreactor system for preparing 4,4'-diaminodiphenyl ether, comprising:

[0046] 4,4'-Dinitrodiphenyl ether preparation system;

[0047] A microtube reaction system set up after the 4,4'-dinitrodiphenyl ether reactant preparation system.

[0048] A collection system is installed after the microtube reactor.

[0049] like Figure 4 , Figure 6 The microtube reaction system includes a microtube reactor 210, which is provided with a hydrogenation port 211 and a raw material inlet 213.

[0050] The microtube reactor 210 is provided with an inner sleeve 222 and an outer sleeve 225. The gap between the outer sleeve 225 and the inner sleeve 222 is a material channel 215, and the outer sleeve 225 and the inner sleeve 222 are a temperature control medium channel.

[0051] like Figure 4 The microtube reactor shown includes a shell, which is divided into a hydrogenation zone, a feedstock addition zone, a reaction zone, a product discharge zone, an inner tube cooling medium addition zone, and an inner tube cooling medium discharge zone.

[0052] The hydrogenation zone is located between the hydrogenation port 211 and the raw material addition zone. The raw material addition zone is located between the hydrogenation zone and the reaction zone. The raw material inlet 213 is connected to the raw material addition zone. The reaction zone is located between the raw material addition zone and the product discharge zone. Several microtube reactors 210 are arranged in the reaction zone. Each microtube reactor 210 includes an inner sleeve 222 and an outer sleeve 225. The gap between the outer sleeve 225 and the inner sleeve 222 is a material channel 215. The outer sleeve 225 and the inner sleeve 222 are temperature control medium channels. The outer sleeve 225 is the gap between the several material channels 215 and the shell.

[0053] The outer tube inlet 224, outer tube outlet 226 and exhaust port 227 are provided on the shell where the reaction zone is located. The outer tube inlet 224 and outer tube outlet 226 form an outer tube 225 with the shell to control the temperature of several material channels 215. The exhaust port 227 is used to discharge the gas formed by the temperature control medium inside the outer tube 225.

[0054] The product discharge zone is located between the inner tube cooling medium discharge zone and the reaction zone, and the product formed in the reaction zone is discharged through the reaction product outlet 216.

[0055] The inner tube cooling medium discharge area is located in the product discharge area and the inner tube cooling medium addition area. The inner tube cooling medium addition area is located at the top of the shell. Water added through the inner tube inlet 221 enters the inner sleeve 222, and after heat exchange with the material channel 215, it enters the inner tube cooling medium discharge area and is discharged through the inner tube water outlet 223.

[0056] The specific implementation process is as follows: In the microtube reactor 210, hydrogen gas enters the microtube reactor 210 through the hydrogenation port 211. 4,4'-dinitrodiphenyl ether, catalyst, and solvent enter the microtube reactor 210 through the raw material inlet 213. Under the action of the catalyst and hydrogen gas, 4,4'-dinitrodiphenyl ether completes the reduction reaction in the material channel 215 to obtain 4,4'-diaminodiphenyl ether. The 4,4'-diaminodiphenyl ether liquid, catalyst, and hydrogen gas are discharged from the reaction product outlet 216. In order to control the reaction... Depending on the temperature, water is introduced into the inner tube inlet 221, flows along the inner sleeve 222, and finally exits at the inner tube outlet 223. Water is introduced into the outer tube inlet 224, flows along the outer tube, and finally exits at the outer tube outlet 226. An exhaust port 227 is provided on the outer tube. The material channel 215 and the inner sleeve are nested together. Several reaction channels and inner sleeves are arranged inside the microtube reactor 210. The distance between each reaction channel is 32mm, the diameter of the inner sleeve is φ22mm, and the sleeve gap is 3mm, that is, the gap of the material channel 215 is 3mm. The reaction channels are filled with water to control the reaction temperature.

[0057] like Figure 5 yes Figure 4 In the enlarged view at point A, hydrogen enters the microtube reactor 210 through the hydrogen inlet 211 and then passes through the hydrogen channel 212 and the microporous tube 217 before entering the gas-liquid mixing zone 218. 4,4'-dinitrodiphenyl ether, catalyst, and solvent enter the microtube reactor 210 through the raw material inlet 213 and pass through the raw material channel 214. After mixing with hydrogen in the gas-liquid mixing zone 218, 4,4'-dinitrodiphenyl ether undergoes a reduction reaction in the material channel 215 under the action of the catalyst and hydrogen to generate 4,4'-diaminodiphenyl ether liquid.

[0058] The catalyst used in this embodiment is a solid powder palladium-on-carbon catalyst. To prevent the catalyst from clogging the microchannels of the reactor, the catalyst is made of fine particles with an average particle size of 16 μm. The diameter of the material channel 215 in the microreaction channel is 187.5 times the particle size of the catalyst, which can effectively avoid clogging of the microreactor channel. At the same time, the reactor adopts a sleeve-type microtube reactor with a straight tube reaction channel, which avoids the disadvantage of easy clogging of labyrinth-type microchannels.

[0059] Example 2

[0060] Based on Example 1, Figure 4 , Figure 5 The microtube reactor 210 in the middle is replaced with, for example Figure 6 , Figure 7 The microtube reactor 210 shown is

[0061] like Figure 6The microtube reactor shown is Figure 4 The microtube reactor shown differs in that an outer tube cooling medium inlet zone is set between the raw material inlet zone and the reaction zone, and an outer tube cooling medium outlet zone is set between the reaction zone and the product outlet zone. Several outer tubes 225 are connected to the outer tube cooling medium inlet zone and the outer tube cooling medium outlet zone, forming an outer tube 225 temperature control system. This allows for temperature control of the material channel 215 through the inner tube 222 and the outer tube 225. Compared to the microtube reactor of Example 1, this embodiment has a separate outer tube 225 outside each material channel 215, enabling more accurate temperature control and improving reaction efficiency and water conservation. In this embodiment, the exhaust port 227 may or may not be provided.

[0062] In the specific implementation process, 4,4'-dinitrodiphenyl ether obtained from the 4,4'-dinitrodiphenyl ether preparation system is introduced into the microtube reaction system. Hydrogen and 3% palladium-on-carbon catalyst are continuously added to the microtube reactor 210 through the hydrogenation port 211 and the raw material inlet 213, respectively, to achieve a hydrogenation catalytic reduction reaction. After the reaction is completed in the microtube reaction system, the resulting 4,4'-diaminodiphenyl ether is collected through a collection system. The microtube reactor 210 is equipped with an inner sleeve 222 and an outer sleeve 225. The gap between the outer sleeve 225 and the inner sleeve 222 serves as a material channel 215, and the outer sleeve 225 and the inner sleeve 222 serve as a temperature-controlled medium channel. Cooling water is introduced into the inner sleeve 222 and outer sleeve 225 of the hydrogenation microtube reactor 210 to control the reaction temperature. In this embodiment, the inner sleeve of the microtube reactor 210 is specifically set with a diameter of φ22mm, an outer sleeve with a diameter of φ32mm, and a sleeve gap of 3mm, thereby forming an annular microchannel.

[0063] Example 3

[0064] Based on the above embodiment 1 or embodiment 2, the microtube reaction system further includes a circulating temperature control medium system for circulating cooling of the microtube reactor 210. The circulating temperature control medium system includes a hot water tank 228 connected to the inner sleeve 222 and the outer sleeve 225, and a soft water tank 229 for replenishing the hot water tank 228.

[0065] In the implementation process, the circulating temperature control medium system supporting the microtube reactor 210 consists of a hot water tank 228, a hot water pump, a soft water tank 229, and a makeup water pump. During the hydrogenation reaction, the reaction temperature is normally controlled within the range of 110°C - 115°C. Since the hydrogenation reaction is an exothermic reaction, a certain temperature must be reached initially for the reaction to proceed rapidly. Moreover, if the amount of circulating cooling water introduced is too large in the later stage, it is easy to reduce the temperature of the feed liquid, slow down the reaction, and cause incomplete reaction of the raw materials. Therefore, hot water at 75°C - 85°C is used for preheating the reaction feed liquid and controlling the reaction temperature. Through the circulating temperature control medium system, the inlet water temperature of the microreactor can be controlled at 75°C, and the outlet water temperature is 80 - 85°C. After the circulating temperature control medium is cooled by the circulating water in the heat exchanger, it returns to the hot water tank 228 to实现热水的循环.

[0066] Example 4

[0067] On the basis of the above Example 1 or 2, more specifically, the 4,4'-dinitrodiphenyl ether preparation system includes: a 4,4'-dinitrodiphenyl ether intermediate tank 110, into which nitrogen can be introduced, and the 4,4'-dinitrodiphenyl ether intermediate tank 110 is provided with a 4,4'-dinitrodiphenyl ether addition port and a N2 addition port; a feed liquid metering tank 120 arranged behind the 4,4'-dinitrodiphenyl ether intermediate tank 110; a batching kettle 130 arranged behind the feed liquid metering tank 120, into which nitrogen can be introduced; and the feed liquid of the batching kettle 130 is introduced into the microtube reactor 210 through a metering pump 140.

[0068] In the 4,4'-dinitrodiphenyl ether preparation system, the 4,4'-dinitrodiphenyl ether obtained through the condensation reaction is stored in the 4,4'-dinitrodiphenyl ether intermediate tank 110, and nitrogen is introduced into the 4,4'-dinitrodiphenyl ether intermediate tank 110 to protect the 4,4'-dinitrodiphenyl ether. In order to more precisely control the reaction amount of 4,4'-dinitrodiphenyl ether, the materials in the 4,4'-dinitrodiphenyl ether intermediate tank 110 are metered through the feed liquid metering tank 120, and the metered 4,4'-dinitrodiphenyl ether is introduced into the batching kettle 130 for pre-batching, and then the feed liquid of the batching kettle 130 is introduced into the microtube reactor 210 through the metering pump 140.

[0069] Example 5

[0070] It should be noted that there is an unclear expression "实现热水的循环" in the original text. I have translated it as literally as possible, but it may need to be adjusted according to the actual meaning.Based on the technical solutions of Embodiment 1 or 2 above, the receiving system includes: a material receiving vessel 310 disposed after the microtube reactor; a filter 320 disposed after the material receiving vessel 310; a concentration vessel 330 disposed after the filter 320; a cooling crystallization vessel 340 disposed after the concentration vessel 330; a centrifuge 350 disposed after the cooling crystallization vessel 340; and a drying receiving device 360 ​​disposed after the centrifuge 350.

[0071] The specific implementation process of the material receiving system is as follows:

[0072] After 4,4'-dinitrodiphenyl ether undergoes hydrogenation catalytic reduction in a microtube reactor, the resulting crude 4,4'-diaminodiphenyl ether reaction solution enters a material receiving vessel 310. The catalyst in the crude 4,4'-diaminodiphenyl ether reaction solution is filtered out by a filter 320. The filtered catalyst can be recycled. The filtered 4,4'-diaminodiphenyl ether liquid is then sent to a concentration vessel 330. The concentrated 4,4'-diaminodiphenyl ether is crystallized in a cooling crystallization vessel 340, and impurities and unreacted substances are further removed by a centrifuge 350. Finally, the 4,4'-diaminodiphenyl ether is dried and collected in a drying receiving device 360.

[0073] Example 6

[0074] In order to maintain a constant pressure in the material receiving vessel 310, based on the above embodiment 5, a pressure relief system is provided after the material receiving vessel 310. The pressure relief system includes a pressure relief buffer tank 510 connected to the material receiving vessel 310, a condenser 520 provided after the pressure relief buffer tank 510, a water seal system 530 provided after the condenser 520, and an evacuation device 540 provided after the water seal system 530.

[0075] Specifically, the high-pressure gas in the material receiving vessel 310 is discharged into the pressure relief buffer tank 510, the high-temperature gas is cooled by the condenser 520, and the water seal system 530 absorbs the soluble substances in the cooled gas. Finally, the clean gas is discharged through the venting device 540.

[0076] Example 7

[0077] Since the hydrogen usage in the reaction system is a molar ratio of material to hydrogen of 1:8-12, the theoretical hydrogen consumption per ton of product for 4,4'-diaminodiphenyl ether is 60 kmol, the actual hydrogen consumption is 80-120 kmol, and the actual average consumption is 1120 m³. 3 Hydrogen, currently used in batch reactor hydrogenation, with a hydrogen consumption of approximately 870 m³ for replacement and hydrogenation. 3Therefore, without hydrogen recovery technology, a large amount of hydrogen would be wasted during industrialization, leading to resource waste and increased product costs. To ensure the hydrogenation catalytic reaction in the microtube reactor 210 proceeds fully, and to recover excess hydrogen and reduce waste, a gas-liquid separation device 400 is installed between the microtube reaction system and the receiving system, based on Example 1 or 2.

[0078] like Figure 2 Hydrogen is separated from the 4,4'-diaminodiphenyl ether reaction liquid by a gas-liquid separator 400. The gas-liquid separator 400 collects the residual hydrogen from the microtube reactor 210 and introduces it into the batch hydrogenation reactor 401. The residual hydrogen discharged from the microtube reactor 210 has a high pressure, reaching 1.0-2.0 MPa. This allows for the utilization of the hydrogen in the batch hydrogenation reactor. In the batch hydrogenation process, the hydrogenated liquid and hydrogen from the fixed-bed reactor undergo gas-liquid separation. The gas-liquid separator maintains the hydrogen pressure in the fixed-bed reactor, ensuring that most of the hydrogen participates in the reaction. This minimizes excess hydrogen while ensuring complete reaction. The remaining high-pressure hydrogen enters the batch hydrogenation reactor for further hydrogenation. The separated liquid undergoes post-processing, including cooling, crystallization, centrifugation, and drying.

[0079] Example 8

[0080] like Figure 3 In another embodiment of hydrogen recovery, different from embodiment 7, the gas-liquid separation device 400 collects the hydrogen remaining from the reaction in the microtube reactor 210 and then reintroduces it into the microtube reactor 210 via a booster pump. Alternatively, the remaining hydrogen can be pressurized using a screw booster pump and then returned to the microtube reactor 210 to continue participating in the reaction.

[0081] Finally, in this system, the product filtered by filter 320 is a catalyst, which can be reused by pressurizing nitrogen back into the batching vessel. The steam from the hot water tank 228 can be used to heat the batching vessel 130.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous microreactor system for preparing 4,4'-diaminodiphenyl ether, comprising: 4,4'-Dinitrodiphenyl ether preparation system; A microtube reaction system set up after the 4,4'-dinitrodiphenyl ether reactant preparation system. A receiving system located after the microtube reaction system; Its features are, The microtube reaction system includes a microtube reactor (210), which is provided with a hydrogenation port (211) and a raw material inlet (213) for introducing 4,4'-dinitrodiphenyl ether reaction liquid and catalyst. The microtube reactor (210) is provided with an inner sleeve (222) and an outer sleeve (225). The gap between the outer sleeve (225) and the inner sleeve (222) is a material channel (215). The outer sleeve (225) and the inner sleeve (222) are a temperature control medium channel. A gas-liquid separator (400) is provided between the microtube reaction system and the receiving system. The gas-liquid separator (400) collects the hydrogen gas remaining in the microtube reactor (210) and then reintroduces it into the microtube reactor (210) through a booster pump.

2. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 1, characterized in that, The microtube reaction system also includes a circulating temperature control medium system for circulating cooling of the microtube reactor (210), the circulating temperature control medium system including a hot water tank (228) connected to the inner sleeve (222) and the outer sleeve (225), and a soft water tank (229) for replenishing the hot water tank (228).

3. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 1, characterized in that, The 4,4'-dinitrodiphenyl ether preparation system includes: 4,4'-dinitrodiphenyl ether intermediate tank (110), wherein nitrogen gas can be introduced into the 4,4'-dinitrodiphenyl ether intermediate tank (110), and the 4,4'-dinitrodiphenyl ether intermediate tank (110) is provided with a 4,4'-dinitrodiphenyl ether inlet and an N2 inlet; The feed metering tank (120) is located after the intermediate tank (110) of the 4,4'-dinitrodiphenyl ether. A mixing vessel (130) is installed after the liquid metering tank (120), and nitrogen gas can be introduced into the mixing vessel (130); The feed liquid in the batching tank (130) is fed into the microtube reactor (210) through the metering pump (140).

4. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 1, characterized in that, The receiving system includes: The material receiving vessel (310) is located after the microtube reactor. A filter (320) is installed after the material receiving vessel (310); Concentrator (330) is located after filter (320); A cooling crystallization vessel (340) is installed after the concentration vessel (330); Centrifuge (350) is installed after the cooling crystallizer (340); A drying receiving device (360) is installed after the centrifuge (350).

5. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 4, characterized in that, A pressure relief system is provided after the material receiving vessel (310). The pressure relief system includes a pressure relief buffer tank (510) connected to the material receiving vessel (310), a condenser (520) provided after the pressure relief buffer tank (510), a water seal system (530) provided after the condenser (520), and an air venting device (540) provided after the water seal system (530).

6. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 1, characterized in that, The gas-liquid separation device (400) collects the hydrogen gas remaining from the reaction in the microtube reactor (210) and then introduces it into the intermittent hydrogenation reactor (401).

7. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 4, characterized in that, The product filtered by the filter (320) is a catalyst.

8. The continuous microreactor 4,4'-diaminodiphenyl ether preparation system as described in claim 2, characterized in that, The steam from the hot water tank (228) is used to heat the batching vessel (130).

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