Method for the preparation of diaminodiphenyl ether by continuous catalytic hydrogenation

Abstract

This invention employs a supported nickel-based catalyst to achieve a method for the continuous catalytic hydrogenation of aminonitrodiphenyl ether to diaminodiphenyl ether. In this method, the catalyst bed in a trickle-bed reactor is filled with a nickel-based catalyst with a higher nickel content in the upper layer and a nickel-based catalyst with a lower nickel content in the lower layer, with the height of the upper layer being half that of the lower layer. An antioxidant is added to the solution to be hydrogenated at a ratio of 0.05% to 0.1% of the mass of the aminonitrodiphenyl ether feedstock. Furthermore, optimization of the catalytic reaction temperature, reaction pressure, and space velocity effectively suppresses the formation of byproducts and improves the conversion rate and selectivity of the reaction.

Description

Technical Field

[0001] This invention relates to a method for the continuous catalytic hydrogenation preparation of diaminodiphenyl ether, belonging to the field of chemical synthesis technology. Background Technology

[0002] 3,4'-Diaminodiphenyl ether (3,4'-ODA), 4,4'-Diaminodiphenyl ether (4,4'-ODA), and 3,3'-Diaminodiphenyl ether (3,3'-ODA) are important diamine intermediates, mainly used as key monomer raw materials for the production of high-temperature resistant resins such as polyimide and polymaleimide. They are also used as raw materials, crosslinking agents, and curing agents for the synthesis of polymers such as epoxy resins and polyurethanes. The cured products have high heat distortion temperature, good thermal stability, and excellent chemical resistance and water resistance. They can also be used as a substitute for benzidine in the production of azo dyes, reactive dyes, and fragrances.

[0003] Currently, the main production method for diaminodiphenyl ether (ODA) is the reduction of dinitrodiphenyl ether (DNDPE) as a raw material. The reduction primarily employs two methods: iron powder reduction and catalytic hydrogenation. The traditional iron powder reduction method is limited due to severe environmental pollution during production. Catalytic hydrogenation, on the other hand, offers advantages such as high product yield, good quality, and less waste, making it the primary method used in industrial production. However, the hydrogenation process involves high temperatures and long processing times, generating byproducts that increase the difficulty of post-processing.

[0004] Technicians have been continuously researching methods for synthesizing diaminodiphenyl ether in order to obtain more economical, green, and efficient new methods for synthesizing diaminodiphenyl ether. One such method involves reacting aminophenol with nitrochlorobenzene to synthesize aminonitrodiphenyl ether, which is then reduced to obtain diaminodiphenyl ether.

[0005] Japanese Patent Application Publication No. 61-221159 discloses a method for obtaining 3-amino-4'-nitrodiphenyl ether by condensing m-aminophenol and p-nitrochlorobenzene at 130-140°C, followed by high-pressure hydrogenation reduction under Pd / C catalysis to obtain crude 3,4'-ODA. This crude product is then added to a high-boiling-point solvent at 240-350°C and subjected to high-vacuum distillation to obtain 3,4'-ODA. This method requires significant equipment investment and is unsafe to operate. Furthermore, the high-vacuum distillation method used in the post-processing results in poor heat transfer, easy coking at the bottom of the vessel, and difficult cleaning.

[0006] Chinese patent CN02137167.9 describes a process in which 3-amino-4'-nitrodiphenyl ether is reduced dropwise with 80% hydrazine hydrate at 50–80°C in a catalyst of FeCl3·6H2O and an alcohol solvent. After reflux for 2–5 hours, water is added to precipitate 3,4'-diaminodiphenyl ether, with a yield of 93% and a purity ≥99% (HPLC). Chinese patent CN200610050813.7 also uses hydrazine hydrate as a reducing agent at a reduction temperature of 70–115°C. After filtration, evaporation, and concentration, 3,4'-diaminodiphenyl ether crystals are crystallized, with a purity ≥99.2%. The preferred reaction solvent is ethylene glycol monomethyl ether. With FeCl3·6H2O / C as the catalyst, the yield of 3,4'-diaminodiphenyl ether is 76.84%; with Pd / C as the catalyst, the yield is 81.71%.

[0007] Chinese patent CN200410025151.9 describes a method for dissolving 3-amino-4'-nitrodiphenyl ether in methanol, using 5% Pd / C as a catalyst, and hydrogenating it for 4-5 hours at 92-98°C and 0.3-1.2 MPa, yielding 72.6% 3,4'-diaminodiphenyl ether with a purity >99.3%. Chinese patent CN201911385092.9 discloses a method for condensing m-aminophenol and p-nitrochlorobenzene in DMF solvent at 100-120°C. The filtrate is transferred to a hydrogenation reactor, where a noble metal catalyst Pd / C and a co-catalyst ferric chloride are added. Catalytic hydrogenation is carried out at 60-80°C under a hydrogen pressure not exceeding 0.5 MPa. After filtration, the filtrate is distilled to remove the solvent, and then further distilled to obtain 3,4'-diaminodiphenyl ether with a purity greater than 99.5% and an overall yield greater than 95%.

[0008] US Patent 4539428A describes a process where a mixture of p-aminophenol, potassium carbonate, p-chloronitrobenzene, and dimethylformamide (DMF) is refluxed at 145–150 °C for 5–6 h under an inert atmosphere to obtain a mixture containing 4-amino-4'-nitrodiphenyl ether. Adding 1%–3% of a Pt / C or Pd / C catalyst to the reaction mixture and directly reducing it with hydrogen without separating the intermediate products yields 4,4'-ODA.

[0009] Canadian patent CA992991A describes a condensation reaction of p-nitrochlorobenzene and p-aminophenol at 145–147 °C for 5 h using DMF as solvent and potassium carbonate as catalyst to yield 4-amino-4'-nitrodiphenyl ether with a yield of 97.5%. The condensation reaction mixture was then hydrogenated under 5% Pd / C catalysis at 0.414 MPa hydrogen pressure to yield 4,4'-ODA with a reduction yield of 87%.

[0010] Hydrazine hydrate can be used as a hydrogen donor for hydrogenation reduction, which is a mild reaction with high yield. However, hydrazine hydrate is highly corrosive and toxic, expensive, and requires an excess amount and a catalyst, resulting in high production costs and making it unsuitable for large-scale economic production.

[0011] Catalytic hydrogenation is a more environmentally friendly method for preparing diaminodiphenyl ether. This method involves placing aminonitrobenzene diphenyl ether (ANDPE) in a hydrogen atmosphere and reacting it under the action of a hydrogenation catalyst to obtain diaminodiphenyl ether. The catalysts mainly use noble metal catalysts such as Pd / C and Pt / C. The hydrogenation reaction often uses a batch reactor. Due to limitations in mass and heat transfer, the reaction efficiency is relatively low. To ensure the complete hydrogenation reaction, high pressure and a long reaction time are usually required. Pd / C and Pt / C are powdered catalysts, which are difficult to separate from the reactants and products, resulting in significant losses during filtration and regeneration. Furthermore, the interaction between the carbon support surface of the Pd / C catalyst and Pd is weak, making Pd easily detached and lost. Fresh catalyst needs to be replenished each time, leading to high catalyst costs. Summary of the Invention

[0012] The purpose of this invention is to provide a method for the continuous catalytic hydrogenation preparation of diaminodiphenyl ether, using aminonitrobenzene diphenyl ether (ANDPE) as raw material and employing a non-precious metal catalyst to achieve continuous catalytic hydrogenation in a fixed catalyst bed.

[0013] To address the aforementioned and / or other problems of existing technologies, this invention employs a supported nickel-based catalyst for continuous catalytic hydrogenation to prepare diaminodiphenyl ether in a trickle-bed reactor. This method features a simple process flow, excellent mass and heat transfer performance, precise control of reaction conditions for continuous operation, shortened reaction time, reduced side reactions, and improved equipment utilization. It also improves product quality, reduces emissions of waste gas, wastewater, and solid waste, and possesses significant economic, safety, and environmental value.

[0014] This invention employs a trickle-bed reactor, specifically a fixed-bed catalytic reactor with parallel downward gas-liquid flow, to replace the autoclave reactor, thereby enabling the continuous production of diaminodiphenyl ether from the hydrogenation reaction of ANDPE. The trickle-bed reaction conditions are mild, the product yield is high, and it avoids the problem of catalyst-product separation, making it more efficient than batch reactors and suitable for industrial continuous production.

[0015] Specifically, this invention employs a supported nickel-based catalyst to provide a method for the continuous catalytic hydrogenation of aminonitrodiphenyl ether in a trickle bed reactor to prepare diaminodiphenyl ether, comprising the following steps:

[0016] Step 1) Dissolve the aminonitrodiphenyl ether raw material and antioxidant in an organic solvent to obtain the hydrogenation solution, and heat the hydrogenation solution to 30-60°C; the aminonitrodiphenyl ether raw material is 3-amino-4'-nitrodiphenyl ether, 4-amino-4'-nitrodiphenyl ether and 3-amino-3'-nitrodiphenyl ether.

[0017] Heat hydrogen gas to 30–60°C;

[0018] While the heated liquid to be hydrogenated is pumped into the gas-liquid mixer of the trickle bed reactor, heated hydrogen is also forced into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0019] Step 2), the gas-liquid mixture to be hydrogenated enters the catalyst bed through the distributor of the trickle bed reactor to carry out the catalytic hydrogenation reaction;

[0020] The catalytic hydrogenation reaction is carried out at a temperature of 55–200°C and a pressure of 0.3–5 MPa.

[0021] The space velocity of the gas-liquid mixture to be hydrogenated in the trickle bed reactor is 0.1–3 h⁻¹. -1 ;

[0022] The catalyst bed is filled with a supported nickel-based catalyst; the catalyst bed comprises an upper and a lower bed, the volume of the upper catalyst bed is half the volume of the lower catalyst bed, that is, the height of the upper bed is half the height of the lower bed; the upper and lower layers are filled with different catalysts, the upper layer is filled with a supported nickel-based catalyst with a Ni content of 50%wt to 70%wt, and the lower layer is filled with a supported nickel-based catalyst with a Ni content of 10%wt to 49.9%wt.

[0023] Step 3): The reaction product obtained in step 2) is cooled and subjected to gas-liquid separation to remove the residual hydrogen in the reaction product. The organic solvent is removed by vacuum evaporation and concentration, and ODA is precipitated.

[0024] In the above continuous production process, the ANDPE to be hydrogenated liquid and hydrogen are transported by pumps and compressors / circulating compressors, respectively. After being preheated to a temperature of 30-60°C, they are fully mixed in a gas-liquid mixer to form a gas-liquid mixture to be hydrogenated. Then, it enters a trickle bed adiabatic reactor containing a hydrogenation catalyst, where the chemical reaction of ANDPE hydrogenation to generate ODA is completed. The reaction products (mainly ODA and water), solvent, and residual hydrogen are discharged from the reactor in the reaction heat. The liquid phase product separated in the gas-liquid separator is sent to a distillation tower. The solvent is distilled off to obtain crude ODA, or part of the solvent is distilled off, concentrated, and crystallized to precipitate ODA crystals. At the same time, the solvent is recovered (recycled). The residual hydrogen from the gas-liquid separator is cooled, pressurized by a circulating compressor, and returned to the system. The crude ODA is refined to produce the finished product that meets the requirements.

[0025] In the gas-liquid mixer, the ANDPE liquid to be hydrogenated and hydrogen are thoroughly mixed to form a well-dispersed gas-liquid mixture. This mixture then enters the catalyst bed through a distributor within the trickle bed for catalytic hydrogenation. The gas-liquid mixture flows from top to bottom within the reactor, preventing the catalyst from being carried away by the reaction liquid. The product remains a gas-liquid mixture, eliminating the need for catalyst separation. The reaction in the trickle bed reactor can be carried out at both lower and higher temperatures, but with a short residence time, effectively reducing the formation of side reactions and achieving ideal yields and purity.

[0026] In step 1) of the present invention, the aminonitrobenzene diphenyl ether (ANDPE) includes any one of 3-amino-4'-nitrodiphenyl ether, 4-amino-4'-nitrodiphenyl ether and 3-amino-3'-nitrodiphenyl ether, so that ODA products with different structures can be produced accordingly.

[0027] In this invention, to keep the catalyst wet and to better facilitate the hydrogenation reaction in the trickle bed reactor, ANDPE needs to be dissolved in a solvent. Choosing a suitable solvent can also extend the catalyst's lifespan. The solvent mentioned in step 1) can be one or more of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tetrahydrofuran, ethyl acetate, toluene, xylene, DMF, and DMAC.

[0028] In step 1), the concentration of ANDPE in the hydrogenation solution affects the reaction conversion rate and product purity. The mass concentration of ANDPE in the solvent is preferably 5wt% to 45wt%, and more preferably 15wt% to 35wt%.

[0029] To prevent ANDPE from being oxidized during the process, an antioxidant is added to the hydrogenation solution. The antioxidant can be selected from sodium bisulfite, potassium bisulfite, sodium sulfite and sodium metabisulfite. The preferred antioxidant is sodium bisulfite or potassium bisulfite, and the more preferred antioxidant is sodium bisulfite. The amount of antioxidant is 0.05% to 0.1% of the mass of ANDPE.

[0030] The catalyst used in the catalytic hydrogenation of this invention is a non-precious metal catalyst, specifically a supported nickel-based catalyst. In step 2), the supported non-precious metal catalyst is at least one of NiSiO, Ni / SiO2, Ni2P / SiO2, Ni / SiO2-TiO2, Ni / SiO2-La2O3, NiAlO, Ni / Mg(Al)O, Ni / Al2O3, and Ni / Al2O3-TiO2, wherein the mass fraction of metallic nickel is 10% to 70%.

[0031] The catalyst of this invention is a supported nickel-based catalyst. It can be prepared by impregnation method, in which nickel salt impregnation solution is loaded onto a porous support, and then reduced, dried and calcined.

[0032] The supported non-precious metal catalyst support is at least one of diatomaceous earth, alumina, silicon dioxide, titanium dioxide, and composite oxides SiO2-La2O3, Al2O3-TiO2, and Mg(Al)O, preferably a mesoporous composite oxide with high surface area, including but not limited to SiO2-La2O3, Al2O3-TiO2, and Mg(Al)O, and more preferably an Al2O3-TiO2 support.

[0033] Oxide supports are commercially available, and mesoporous composite oxides can be prepared using common techniques. For example, TiO2-Al2O3 composite supports can be prepared using the sol-gel method and precipitation method. The sol-gel method uses macroporous γ-Al2O3 as the base support, mixing alumina powder with titanium sol, and then grafting titanium oxide onto the γ-Al2O3 surface using the sol-gel method. The precipitation method uses ammonia as the precipitant and titanium sulfate and aluminum sulfate as the titanium and aluminum sources, respectively, and is prepared using a co-precipitation method.

[0034] The nickel-based catalyst described above is prepared using techniques commonly used in the field of catalyst preparation, such as impregnation and co-precipitation, which can meet the requirements of the method of this invention. The mass percentage of nickel in the catalyst is 10-70%.

[0035] The present invention uses nickel salt as nickel source precursor salt. The nickel salt is selected from at least one of nickel nitrate, nickel chloride, nickel sulfate, nickel formate, nickel acetate, nickel oxalate, and nickel citrate. The precursor salt is preferably nickel nitrate, specifically nickel nitrate hexahydrate.

[0036] When prepared by co-precipitation, the precipitate is washed, dried, and calcined, and then granulated, tableted, or extruded to form catalyst particles with a certain strength.

[0037] The precipitant is selected from one or more of potassium carbonate, potassium bicarbonate, sodium carbonate, sodium bicarbonate, ammonium carbonate, and ammonium bicarbonate.

[0038] For continuous hydrogenation in a trickle bed reactor, the catalyst used must not only have stable performance and appropriate activity, but also high particle strength to maintain its active lifespan for a longer period. Therefore, the catalyst must be shaped. The catalyst solid powder is mixed with a binder and granulated using a granulator to obtain catalyst particles of the desired shape.

[0039] The supported non-precious metal catalyst can be at least one of the following shapes: spherical particles, four-ribbed wheels, four-hole cylinders, hollow cylinders, extrusion strips, clover, multileaf clover, etc. The preferred catalyst shapes are spherical particles and clover. Since the porosity fluctuation of clover particles is smaller than that of spherical particles, clover particles are more preferred. The size is 200-2000 micrometers. It can be matched with the reaction temperature, reaction pressure, residence time and other parameters of the above-mentioned catalytic hydrogenation process to synergistically improve the reaction efficiency, product yield and purity.

[0040] To ensure the catalyst remains stable in the trickle bed reactor during hydrogenation, the catalyst precursor must be shaped into the desired form, such as clover-shaped particles. Therefore, the choice of binder is crucial. The binder is selected from one or more of silica sol, polytetrafluoroethylene (PTFE), and perfluorosulfonic acid-PTFE copolymer (Nafion).

[0041] The catalysts Ni / SiO2 and Ni / Al2O3 are prepared by an equal-volume impregnation method, in which a nickel salt solution, such as an aqueous solution of Ni(NO3)2·6H2O, is impregnated onto the carriers SiO2 and Al2O3, respectively. After drying, calcination, grinding, and shaping, they are finally reduced by passing H2 through them.

[0042] The Ni2P catalyst was prepared using a traditional temperature-programmed reduction method. Nickel salt and phosphate salt were mixed together to form a solution. The nickel salt was nickel nitrate hexahydrate, and the phosphate salt was selected from triphenylphosphine, tri-n-octylphosphine, and tri-n-octylphosphine oxide. The SiO2 support was impregnated with the solution, and after drying, calcination, grinding, and shaping, it was finally reduced by passing H2 to obtain the Ni2P / SiO2 catalyst.

[0043] The Ni / Mg(Al)O catalyst was prepared by a one-step co-precipitation method. A certain amount of nickel nitrate hexahydrate, magnesium nitrate hexahydrate, and aluminum nitrate nonahydrate were dissolved in deionized water to form a salt solution; a certain amount of anhydrous sodium carbonate and sodium hydroxide were dissolved in deionized water to form an alkaline solution. Under vigorous stirring, the salt and alkaline solutions were simultaneously and slowly added dropwise, controlling the pH value. After the addition was complete, the reaction was continued at a certain temperature for a period of time. The mixture was then allowed to cool naturally, filtered, washed with water, and washed with alcohol to remove soluble components until the pH reached approximately 7. The filter cake was then vacuum-dried to obtain the catalyst precursor, calcined, and finally reduced in a hydrogen atmosphere to obtain Ni / Mg(Al)O catalysts with different loadings.

[0044] The catalyst Ni / Al2O3-TiO2 can be prepared by the equal volume impregnation method. Nickel nitrate hexahydrate (Ni(NO3)2·6H2O) is used as the nickel source to impregnate the composite support TiO2-Al2O3. After drying, calcination, grinding, and shaping, it is finally reduced by passing H2 to obtain the Ni / Al2O3-TiO2 catalyst.

[0045] The catalyst bed is randomly packed. In step 2), to achieve the purpose of this invention, the catalyst bed in the trickle bed is filled with nickel-based catalysts with different active component contents. The trickle bed reactor bed is divided into two layers. At the top inlet, the upper bed is filled with a high-nickel catalyst with an active component Ni content of 50wt% to 70wt%, preferably 50wt% to 55wt%, and the lower bed is filled with a nickel-based catalyst with an active component Ni content of 10wt% to 49.9wt%, preferably 10wt% to 20wt%, preferably a low-nickel catalyst. Since ANDPE catalytic hydrogenation is a strongly exothermic reaction, filling the upper layer with a high-nickel catalyst allows the inlet reaction temperature to be started at a lower temperature range (30 to 55°C). Then, the reaction temperature is raised using its own heat of reaction to reach thermodynamic equilibrium. After thermodynamic equilibrium, the outlet temperature is about 15 to 20°C higher than the inlet reaction temperature. This reduces energy consumption, and the composite bed packing of the two catalysts avoids the reaction risk caused by violent exothermic reactions and reduces by-products.

[0046] In step 1), the gas-liquid mixer preferably includes one of a gas-liquid mixing injector, a micro-sieve reactor, or a T-type reactor, or it can be other mixers that can achieve uniform mixing of the gas-liquid system of the present invention.

[0047] In step 2), the gas-liquid mixture flowing from the gas-liquid mixer is evenly distributed onto the catalyst bed via a distributor within the trickle bed. Commonly used nozzle-type, spray-type, sieve-plate-type, and pipe-type distributors for trickle beds can all be used as the gas-liquid mixture distributor in this invention. Alternatively, filling the upper part of the catalyst bed with an inert particle layer can also achieve the purpose of gas-liquid mixture distribution. If necessary, a distributor can be installed between two catalyst bed layers to redistribute the reaction mixture.

[0048] In step 2), the optimal reaction conditions are: a temperature of 90–130°C, a pressure of 0.8–1.5 MPa, and a space velocity of 0.1–1 h⁻¹ for the hydrogenated liquid. -1 ;

[0049] In step 1), the molar ratio of ANDPE to hydrogen in the liquid to be hydrogenated is preferably 1:3.1 to 1:6, and more preferably 1:3.2 to 1:3.5.

[0050] In step 3), the high-pressure separation buffer tank regulates the pressure of the trickle bed reactor system by controlling the discharge of non-condensable gas and hydrogenated solution.

[0051] The gas obtained from gas-liquid separation contains hydrogen and can enter the tail gas treatment system. It can be compressed, cooled, dehydrated, and recycled, such as for mixing with the solution to be hydrogenated in step 1).

[0052] The present invention relates to a method for the continuous catalytic hydrogenation of aminonitrodiphenyl ether to diaminodiphenyl ether using a trickle bed reactor. This method employs a supported nickel-based catalyst and a catalyst bed packing configuration where the upper layer is filled with a higher nickel-based catalyst and the lower layer with a lower nickel-based catalyst. The heat of reaction generated by the catalytic hydrogenation reaction is utilized to achieve thermodynamic equilibrium, thereby reducing reaction energy consumption and avoiding the risks associated with violent exothermic reactions and the generation of other byproducts. Furthermore, the optimization and control of the catalytic reaction temperature, reaction pressure, and space velocity effectively suppress the generation of byproducts such as hydroxylamine condensation and aminoazolation, thus improving the conversion rate and selectivity of the reaction. Detailed Implementation

[0053] The present invention will be further illustrated by the following examples, but the present invention is not limited to these specific embodiments.

[0054] The reaction products can be separated and purified using conventional techniques, including but not limited to filtration, distillation, crystallization, and chromatography. These materials can be characterized using conventional methods, including physical constants and spectroscopic data.

[0055] Example 1: Preparation of 3,4'-diaminodiphenyl ether

[0056] The method in Example 1 includes the following steps:

[0057] Step 1) Dissolve 3-amino-4'-nitrodiphenyl ether raw material in an organic solvent to obtain a hydrogenation liquid, and heat the hydrogenation liquid to 30-60°C; heat hydrogen gas to 30-60°C; pump the heated hydrogenation liquid into the gas-liquid mixer of the trickle bed reactor, and simultaneously pressurize the heated hydrogen gas into the gas-liquid mixer to fully mix with the hydrogenation liquid to form a gas-liquid mixture to be hydrogenated.

[0058] In this embodiment, the raw material ANDPE is 3-amino-4'-nitrodiphenyl ether with a purity greater than 99.5% wt. The organic solvent is DMAC, and the antioxidant sodium bisulfite is added at 0.1% of the mass of 3-amino-4'-nitrodiphenyl ether. A DMAC hydrogenation solution is prepared, in which the concentration of 3-amino-4'-nitrodiphenyl ether is 20 wt%.

[0059] The heated liquid to be hydrogenated is pumped into the gas-liquid mixer using a dual-plunger micro-pump (at a flow rate of 15.0 mL / h). Simultaneously, heated hydrogen gas (at a flow rate of 0.95 L / h) is pressurized into the gas-liquid mixer using a compressor or circulating compressor to thoroughly mix with the liquid to be hydrogenated, forming a well-dispersed gas-liquid mixture.

[0060] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:3.45, and the space velocity is 0.15 h⁻¹. -1 .

[0061] Step 2), the gas-liquid mixture to be hydrogenated enters the catalyst bed through a distributor in the trickle bed reactor to carry out the catalytic hydrogenation reaction.

[0062] In this embodiment, the catalyst is a clover-shaped Ni / Al2O3-TiO2. The upper bed is filled with a high-nickel-based catalyst with a Ni content of 50%wt (the active component Ni accounts for 50%wt, and the remainder is Al2O3-TiO2 support); the lower bed is filled with a low-nickel-based catalyst with a Ni content of 15%wt (the active component Ni accounts for 15%wt, and the remainder is Al2O3-TiO2 support).

[0063] In this embodiment, the reactor wall temperature of the catalyst bed is set at 130°C (the reaction temperature of the catalytic hydrogenation reaction), the device pressure is maintained at 1.0 MPa (the reaction pressure of the catalytic hydrogenation reaction), the gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor. The temperature at the reactor outlet is about 150°C (the exothermic reaction of the catalytic hydrogenation reaction causes the temperature of the reaction products to rise).

[0064] Analysis of the obtained products showed that the yield of 3,4'-ODA was 99.47%, and no byproducts were found; the conversion rate of the raw material ANDPE was 100%.

[0065] In a preferred embodiment of the present invention, step 3) is further included: gas-liquid separation is performed on the reaction product obtained in step 2) to remove the residual hydrogen in the reaction product, and the organic solvent is removed by vacuum distillation.

[0066] Specifically, in this embodiment, the reaction product flows out from the outlet (bottom) of the trickle bed reactor and enters a gas-liquid separator (high-pressure separation buffer tank); the remaining hydrogen in the reaction product is discharged from the top of the gas-liquid separator (the discharged hydrogen, after cooling, can be pressurized by a circulating compressor and then returned to step 1), and the liquid phase is discharged from the bottom of the gas-liquid separator, and then the organic solvent (DMAC) is removed by vacuum distillation (distillation column) (the organic solvent can be recycled after recovery); the residue after the removal of the organic solvent is recrystallized to obtain a white solid 3,4'-ODA. In specific production applications, the product is refined to obtain a finished product that meets industrial requirements.

[0067] Example 2: Preparation of 3,4'-diaminodiphenyl ether

[0068] The preparation method of Example 2 differs from that of Example 1 only in that:

[0069] In step 1), o-xylene is used as the organic solvent, and potassium bisulfite is added as the antioxidant at a rate of 0.1% of the mass of 3-amino-4'-nitrodiphenyl ether to prepare the o-xylene hydrogenation solution of ANDPE; in this hydrogenation solution, the concentration of 3-amino-4'-nitrodiphenyl ether is 5 wt%.

[0070] In step 1), a dual-plunger micro-pump (at a flow rate of 60.0 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 1.65 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0071] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:6.0, and the space velocity is 0.15 h⁻¹.-1 .

[0072] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 70%wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 10%wt.

[0073] The reactor wall temperature of the catalyst bed is set at 90℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 1.5MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0074] Analysis of the obtained products showed that the yield of 3,4'-ODA was 98.33% and the conversion rate of the raw material ANDPE was 99.82%.

[0075] Example 3: Preparation of 3,4'-diaminodiphenyl ether

[0076] The preparation method of Example 3 differs from that of Example 1 only in that:

[0077] In step 1), o-xylene is used as the organic solvent to prepare the o-xylene hydrogenation solution of ANDPE; in the hydrogenation solution, the concentration of ANDPE raw material is 5 wt%.

[0078] In step 1), a dual-plunger micro-pump (at a flow rate of 60.0 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 0.86 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0079] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:3.12, and the space velocity is 0.15 h⁻¹. -1 .

[0080] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 55%wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 15%wt.

[0081] The reactor wall temperature of the catalyst bed is set at 85℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 0.3MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0082] Analysis of the obtained products showed that the yield of 3,4'-ODA was 99.09%, and the conversion rate of the raw material ANDPE was 100%.

[0083] Example 4: Preparation of 3,4'-diaminodiphenyl ether

[0084] The preparation method of Example 4 differs from that of Example 1 only in that:

[0085] In step 1), methanol is used as the organic solvent, and sodium bisulfite, an antioxidant, is added at 0.05% of the mass of 3-amino-4'-nitrodiphenyl ether to prepare the methanol hydrogenation solution of ANDPE; in this hydrogenation solution, the concentration of ANDPE raw material is 45 wt%.

[0086] In step 1), a dual-plunger micro-pump (at a flow rate of 15 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 2.0 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0087] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:3.23, and the space velocity is 0.34 h⁻¹. -1 .

[0088] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 50% wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 15% wt.

[0089] The reactor wall temperature of the catalyst bed is set at 70℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 5.0MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0090] Analysis of the obtained products showed that the yield of 3,4'-ODA was 95.66%, the conversion rate of the feedstock ANDPE was 95.86%, and the conversion rate of the feedstock 3-amino-4'-nitrodiphenyl ether was 4.14%.

[0091] Example 5: Preparation of 3,4'-diaminodiphenyl ether

[0092] The preparation method of Example 5 differs from that of Example 1 only in that:

[0093] In step 1), the organic solvent used is n-butanol, and the antioxidant sodium sulfite is added at 0.1% of the mass of 3-amino-4'-nitrodiphenyl ether to prepare the n-butanol hydrogenation solution of ANDPE; in this hydrogenation solution, the concentration of ANDPE raw material is 5 wt%.

[0094] In step 1), a dual-plunger micro-pump (at a flow rate of 60 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 1.6 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0095] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:5.8, and the space velocity is 0.15 h⁻¹. -1 .

[0096] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 50% wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 45% wt.

[0097] The reactor wall temperature of the catalyst bed is set at 135℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 2.4MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0098] Analysis of the obtained products showed that the yield of 3,4'-ODA was 99.97%, and the conversion rate of the raw material ANDPE was 100%.

[0099] Example 6: Preparation of 3,4'-diaminodiphenyl ether

[0100] The preparation method of Example 6 differs from that of Example 1 only in that:

[0101] In step 1), isopropanol is used as the organic solvent, and sodium metabisulfite is added at 0.1% of the mass of 3-amino-4'-nitrodiphenyl ether to prepare the isopropanol hydrogenation solution of ANDPE; in the hydrogenation solution, the concentration of 3-amino-4'-nitrodiphenyl ether raw material is 15 wt%.

[0102] In step 1), a dual-plunger micro-pump (at a flow rate of 40 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 2.7 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0103] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:4.9, and the space velocity is 0.30 h⁻¹. -1 .

[0104] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 50% wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 20% wt.

[0105] The reactor wall temperature of the catalyst bed is set at 85℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 0.8MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0106] Analysis of the obtained products showed that the yield of 3,4'-ODA was 99.13%, the conversion rate of the raw material ANDPE was 99.34%, and the yield of 3-amino-4'-nitrodiphenyl ether was 0.62%.

[0107] Example 7: Preparation of 3,4'-diaminodiphenyl ether

[0108] The preparation method of Example 7 differs from that of Example 1 only in that:

[0109] In step 1), the organic solvent used is a mixture of tetrahydrofuran and isopropanol (tetrahydrofuran content is 42.8% wt), and the antioxidant sodium bisulfite is added at 0.08% of the mass of 3-amino-4'-nitrodiphenyl ether to prepare the tetrahydrofuran-isopropanol hydrogenation solution of ANDPE; in this hydrogenation solution, the concentration of 3-amino-4'-nitrodiphenyl ether raw material is 35 wt%.

[0110] In step 1), a dual-plunger micro-pump (at a flow rate of 60 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 6.0 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0111] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:3.11, and the space velocity is 1.05 h⁻¹. -1 .

[0112] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 52% wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 49% wt.

[0113] The reactor wall temperature of the catalyst bed is set at 200℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 1.4MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0114] Analysis of the obtained products showed that the yield of 3,4'-ODA was 97.49%, and the conversion rate of the raw material ANDPE was 100%.

[0115] Example 8: Preparation of 4,4'-diaminodiphenyl ether

[0116] The preparation method of Example 8 differs from that of Example 1 only in that:

[0117] In step 1), the raw material ANDPE is 4-amino-4'-nitrodiphenyl ether, and the organic solvent is a mixture of xylene and DMAC (xylene content is 15% wt) to prepare the xylene-DMAC hydrogenation solution of 4-amino-4'-nitrodiphenyl ether; in this hydrogenation solution, the concentration of 4-amino-4'-nitrodiphenyl ether raw material is 25 wt%.

[0118] In step 1), a dual-plunger micro-pump (at a flow rate of 20 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 2.7 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0119] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:5.89, and the space velocity is 0.25 h⁻¹. -1 .

[0120] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 50% wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 15% wt.

[0121] The reactor wall temperature of the catalyst bed is set at 90℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 1.0MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0122] Analysis of the obtained product showed that the yield of 4,4'-ODA was 99.98%, and the conversion rate of the starting material 4-amino-4'-nitrodiphenyl ether was 100%.

[0123] Example 9: Preparation of 3,3'-diaminodiphenyl ether

[0124] The preparation method of Example 9 differs from that of Example 1 only in that:

[0125] In step 1), the raw material is 3-amino-3'-nitrodiphenyl ether, and the organic solvent is a mixed solvent of toluene and DMF (toluene content is 20% wt) to prepare a toluene-DMF hydrogenation solution of 3-amino-3'-nitrodiphenyl ether; in this hydrogenation solution, the concentration of 3-amino-3'-nitrodiphenyl ether is 25 wt%.

[0126] In step 1), a dual-plunger micro-pump (at a flow rate of 20 mL / h) is used to pump the heated liquid to be hydrogenated into the gas-liquid mixer at the top of the trickle bed reactor. At the same time, a compressor or a circulating compressor is used to pressurize the heated hydrogen (at a hydrogen flow rate of 2.75 L / h) into the gas-liquid mixer to fully mix with the liquid to be hydrogenated to form a gas-liquid mixture to be hydrogenated.

[0127] By controlling the flow rate, the molar ratio of the aminonitrobenzene raw material to the hydrogen gas injected into the gas-liquid mixer is approximately 1:6.0, and the space velocity is 0.25 h⁻¹. -1 .

[0128] In step 2), the gas-liquid mixture to be hydrogenated obtained in step 1) is passed through the catalyst bed of the trickle bed reactor (filled with clover-shaped Ni / Al2O3-TiO2 catalyst). The upper bed is filled with a high-nickel-based catalyst with a Ni content of 50% wt, and the lower bed is filled with a low-nickel-based catalyst with a Ni content of 15% wt.

[0129] The reactor wall temperature of the catalyst bed is set at 90℃ (the reaction temperature of the catalytic hydrogenation reaction), and the device pressure is maintained at 1.2MPa (the reaction pressure of the catalytic hydrogenation reaction). The gas-liquid mixture to be hydrogenated is continuously pumped in, and the reaction products are collected at the outlet of the trickle bed reactor.

[0130] Analysis of the obtained product showed that the yield of 3,3'-ODA was 99.94%, and the conversion rate of the starting material 3-amino-3'-nitrodiphenyl ether was 100%.

[0131] Example 10: Preparation of 3,4'-diaminodiphenyl ether

[0132] The difference from Example 1 is that the catalyst bed in the trickle bed reactor is different; it is filled with a clover-shaped Ni / SiO2 catalyst. All other conditions are the same as in Example 1.

[0133] Analysis of the obtained products showed that the yield of 3,4'-ODA was 97.32% and the conversion rate of the raw material ANDPE was 98.55%.

[0134] Example 11: Preparation of 3,4'-diaminodiphenyl ether

[0135] The difference from Example 1 is that the catalyst bed in the trickle bed reactor is different; it is filled with a clover-shaped Ni2P / SiO2 catalyst. All other conditions are the same as in Example 1.

[0136] Analysis of the obtained products showed that the yield of 3,4'-ODA was 98.47%, and the conversion rate of the raw material ANDPE was 99.5%.

[0137] Comparative Example 1

[0138] The difference between Comparative Example 1 and Example 1 lies in the catalyst and packing method of the trickle bed reactor. In Comparative Example 1, the catalyst bed is entirely filled with a low-nickel-based catalyst with a Ni content of 10% wt (the active component Ni accounts for 10% wt, and the remainder is Al2O3-TiO2 support), and the upper and lower layers are filled in the same way. All other operations are the same as in Example 1.

[0139] The reaction products were collected at the outlet of the trickle bed reactor, where the temperature was approximately 140°C. The resulting products were analyzed, and the conversion rate of 3-amino-4'-nitrodiphenyl ether was 95.92%, with a yield of 95.20% for 3,4'-ODA.

[0140] Comparative Example 2

[0141] The difference between Comparative Example 2 and Example 1 lies in the catalyst and packing method of the trickle bed reactor. In Comparative Example 2, the catalyst bed is entirely filled with a high-nickel-based catalyst with a Ni content of 70% wt (Ni accounts for 70% wt of the active component, and the remainder is Al2O3-TiO2 support), and the upper and lower layers are filled in the same way. All other operations are the same as in Example 1.

[0142] The reaction products were collected at the outlet of the trickle bed reactor, where the temperature was approximately 160°C. The resulting products were analyzed, and the conversion rate of 3-amino-4'-nitrodiphenyl ether (DNDPE) was 100%, with a yield of 94.12% for 3,4'-ODA.

[0143] Comparative Example 3

[0144] The difference between Comparative Example 1 and Example 1 is that no antioxidant was added when preparing the 3-amino-4'-nitrodiphenyl ether solution, while the rest of the operation was the same as in Example 1.

[0145] Analysis of the obtained product showed that the conversion rate of 3-amino-4'-nitrodiphenyl ether was 100%, and the yield of 3,4'-ODA was 97.82%.

[0146] The comparison results between Example 1 and Comparative Examples 1 and 2 show that the catalyst bed packing method has a significant impact on the yield of diaminodiphenyl ether. Furthermore, the inventors discovered in their experiments that catalytic hydrogenation is a strongly exothermic reaction. In the present invention, filling the upstream section with a high-nickel-based catalyst allows for initiation of the inlet reaction temperature within a relatively low temperature range (30-55°C). However, if all high-nickel-based catalysts are used, the violent exothermic reaction may lead to reaction risks (explosions) and the generation of other byproducts. Therefore, the inventors use a higher-nickel-based catalyst in the upstream section and a lower-nickel-based catalyst in the downstream section, utilizing the reaction heat generated by the reaction itself to achieve thermodynamic equilibrium (after thermodynamic equilibrium, the outlet temperature is about 15-20°C higher than the inlet reaction temperature). This reduces reaction energy consumption and avoids the reaction risks (explosions) and the generation of other byproducts caused by violent exothermic reactions.

[0147] The method for preparing diaminodiphenyl ether of the present invention, based on the use of a trickle bed reactor, selects a supported nickel-based catalyst (supported non-precious metal catalyst) and a specific packing method, and further optimizes and controls the operating conditions of catalytic reaction temperature, reaction pressure and space velocity, effectively suppressing the generation of byproducts such as incomplete hydrogenation of nitro, hydroxylamine condensation and amino azotization, and improving the conversion rate and selectivity of the reaction.

[0148] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0149] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for the continuous catalytic hydrogenation preparation of diaminodiphenyl ether, characterized in that: The method includes the following steps: Step 1): Dissolve the aminonitrobenzene raw material and antioxidant in an organic solvent to obtain a hydrogenation liquid, and heat the hydrogenation liquid to 30-60°C; the aminonitrobenzene raw material is 3-amino-4'-nitrodiphenyl ether, 4-amino-4'-nitrodiphenyl ether and 3-amino-3'-nitrodiphenyl ether; heat hydrogen to 30-60°C; while pumping the heated hydrogenation liquid into the gas-liquid mixer of the trickle bed reactor, pressurize the heated hydrogen into the gas-liquid mixer to fully mix with the hydrogenation liquid to form a gas-liquid mixture to be hydrogenated; Step 2): The gas-liquid mixture to be hydrogenated enters the catalyst bed through the distributor of the trickle bed reactor for catalytic hydrogenation; the reaction temperature of the catalytic hydrogenation reaction is 55–200°C, and the reaction pressure is 0.3–5 MPa; the space velocity of the gas-liquid mixture to be hydrogenated in the trickle bed reactor is 0.1–3 h⁻¹. -1 The catalyst bed is filled with a supported nickel-based catalyst; the catalyst bed comprises upper and lower layers, the height of the upper layer being 1 / 2 the height of the lower layer; the upper catalyst bed is filled with a supported nickel-based catalyst with a Ni content of 50%wt to 70%wt; the lower catalyst bed is filled with a supported nickel-based catalyst with a Ni content of 10%wt to 20%wt.

2. The method as described in claim 1, characterized in that: In the catalyst bed, the upper catalyst bed is filled with a supported nickel-based catalyst with a Ni content of 50%wt to 55%wt.

3. The method as described in claim 2, characterized in that: In step 2), the reaction temperature of the catalytic hydrogenation reaction is 90–130°C, and the reaction pressure is 0.8–1.5 MPa; the space velocity of the gas-liquid mixture to be hydrogenated in the trickle bed reactor is 0.1–1 h⁻¹. -1 .

4. The method as described in claim 1, characterized in that: The molar ratio of the aminonitrodiphenyl ether raw material to the hydrogen gas pressed into the gas-liquid mixer is 1:3.1 to 1:

6.

5. The method as described in claim 4, characterized in that: The molar ratio of the aminonitrodiphenyl ether raw material to the hydrogen gas pressed into the gas-liquid mixer is 1:3.2 to 1:3.

5.

6. The method according to any one of claims 1 to 5, characterized in that: The method further includes step 3): performing gas-liquid separation on the reaction product obtained in step 2) to remove the residual hydrogen in the reaction product, and removing the organic solvent by vacuum distillation.

7. The method according to any one of claims 1 to 5, characterized in that, In step (2), the supported nickel-based catalyst is at least one of Ni / SiO2, Ni2P / SiO2, Ni / SiO2-La2O3, Ni / Al2O3, and Ni / Al2O3-TiO2.

8. The method according to any one of claims 1 to 5, characterized in that, In step (2), the support for the supported nickel-based catalyst is at least one of diatomaceous earth, alumina, silicon dioxide, titanium dioxide, and composite oxides SiO2-La2O3 and Al2O3-TiO2.

9. The method as described in claim 1, characterized in that: In the catalyst bed, the supported nickel-based catalyst is any one of the following shapes: spherical particles, four-ribbed wheels, four-hole cylinders, hollow cylinders, and multi-leaved grass.

10. The method as described in claim 1, characterized in that: In the supported nickel-based catalyst, the catalyst particle size ranges from 200 to 2000 micrometers.

11. The method according to any one of claims 1 to 5, characterized in that: The organic solvent is any one or a mixture of several of the following: methanol, ethanol, propanol, isopropanol, butanol, isobutanol, tetrahydrofuran, ethyl acetate, toluene, xylene, DMF, and DMAC.

12. The method according to any one of claims 1 to 5, characterized in that: In step 1), the mass concentration of the aminonitrobenzene ether raw material in the hydrogenation solution is 5% to 45%.

13. The method according to any one of claims 1 to 5, characterized in that, In step 1), the gas-liquid mixer is one of a gas-liquid mixing injector, a micro-sieve reactor, or a T-type reactor.

14. The method as described in claim 1, characterized in that: The antioxidant is selected from sodium bisulfite, potassium bisulfite, sodium sulfite, and sodium metabisulfite.

15. The method as described in claim 1, characterized in that: The amount of antioxidant used is 0.05% to 0.1% of the mass of the aminonitrobenzene raw material.