A method for performing a hydrogen transfer reaction using a microreactor device

Abstract

The application discloses a method for hydrogen transfer reaction by using a micro-reactor device, wherein the micro-reactor device comprises a liquid pipeline system, a gas pipeline system, a micro-reactor and a cooling and product collecting system; the top of the micro-reactor is communicated with the liquid pipeline system and the gas pipeline system respectively, and the bottom of the micro-reactor is connected with the cooling and product collecting system; the method comprises the following steps: filling Pt / Al2O3 catalyst in the reaction tube of the micro-reactor; first pumping inert gas into the micro-reactor to discharge air in the micro-reactor, and then continuously pumping raw material liquid formed by mixing alcohol compound of formula I and amine compound of formula II into the micro-reactor to carry out reaction; the reaction liquid flows out of the micro-reactor and then enters the cooling and product collecting system to be collected, so as to obtain product of formula III. The micro-reactor is used to carry out hydrogen transfer reaction, and higher product yield is obtained.

Description

Technical Field

[0001] This invention relates to a method for hydrogen transfer reaction using a microreactor device. Background Technology

[0002] Hydrogen transfer reactions, also known as hydrogen-borrowing reactions, refer to the use of a hydrogen donor as a hydrogen source to dehydrogenate relatively inert organic molecules into metal hydrides under the catalysis of metals and transition metals. Simultaneously, the organic molecules are activated into active substrates that participate in subsequent coupling reactions. The dehydrogenated metal hydrides then undergo a reduction reaction with the active intermediates generated during the reaction to synthesize the target product. Compared to ordinary hydrogenation reactions, this reaction uses non-high-pressure hydrogen as a hydrogen donor and is carried out at atmospheric pressure, offering advantages such as lower reaction temperatures, milder reaction conditions, less demanding equipment requirements, and lower reaction hazards. It has broad application prospects in the production of pharmaceuticals and other fine chemical industries. In organic synthesis, hydrogen transfer reactions can be used to construct carbon-carbon or carbon-hydrogen bonds. For example, hydrogen transfer reactions can achieve the hydrogenation of olefins, converting them into saturated hydrocarbons. Furthermore, hydrogen transfer reactions can also be used to synthesize alcohols and ethers. In the petroleum industry, catalytic cracking is an important refining process that decomposes heavy hydrocarbons into light hydrocarbons. In this process, hydrogen transfer reactions participate in the cracking of hydrocarbons, generating new olefins and hydrocarbons.

[0003] Hydrogen transfer reactions are classified into homogeneous and heterogeneous reactions. In homogeneous hydrogen transfer reactions, patent CN117603047A proposes a method for preparing bio-based polyols. This reaction is carried out in a traditional microreactor. Existing microchannel reactors are relatively expensive, their structure is fixed and cannot be adjusted, and their catalysts are not recyclable. In heterogeneous hydrogen transfer reactions, patent CN116239471A proposes a method for preparing polysubstituted 1,3-butadiene compounds, providing an efficient and diversified synthetic method for polysubstituted 1,3-butadiene compounds with readily available substrates and atom-economical reaction. However, this reaction is carried out in a high-pressure reactor, which suffers from problems such as small heat exchange area, difficulty in controlling reaction temperature, and inconsistent residence time, resulting in low product yields. Patent CN116003352A provides a method for selectively reducing unsaturated compounds using hydrogen transfer. This method has mild reaction conditions, no high-pressure hydrogen hazard, and is environmentally friendly. However, this reaction is carried out in a fixed bed, which suffers from poor heat transfer performance, difficulty in changing catalysts, and susceptibility to clogging.

[0004] Current research on hydrogen transfer reactions mainly focuses on improving reaction efficiency, selectivity, and product purity. These reactions are typically carried out in reactors, but fixed-bed and fluidized-bed reactors are also used to enhance selectivity and yield. This requires specific requirements for catalyst molding, particle uniformity, and mechanical strength. Hydrogen transfer reactions are widely used in petrochemical systems, where large-scale production offers significant advantages. Hydrogen transfer reactions have numerous applications in fine chemicals. For example, in pharmaceutical synthesis, hydrogen transfer reactions can be used to introduce specific saturated groups, improving the pharmacological properties of compounds. In the fragrance industry, hydrogenation reactions are used to produce stable compounds with specific aroma characteristics. Catalyst recovery and recycling are crucial for reducing production costs and improving economic efficiency. For instance, the application of dendritic catalysts in asymmetric hydrogen transfer reactions, through specific design, allows for easy separation and recovery of the catalyst after the reaction, enabling multiple recycling. Hydrogen transfer reactions are usually small-scale. Many catalysts are modified from powdered catalysts used in slurry bed (chamber) reactions. The molding process is complex and can damage the catalyst's pore structure. It is not easy to transfer the catalyst from a slurry bed reactor to a continuous reactor such as a fixed bed or fluidized bed reactor. This cannot meet the requirements of fixed bed or fluidized bed catalysts, and the catalyst is easily lost into subsequent materials.

[0005] Patent CN116236992A discloses a high-efficiency microchannel reactor. Within a certain Reynolds number range, this microreactor allows the material contact surface to rotate and stretch approximately 90°, further increasing the contact area, reducing the mass transfer distance, and improving the mixing effect. Patent CN116966853A describes a microchannel reaction process system and method, simplifying the components of the reactants entering the microchannel reactor. This allows for better utilization of the mass and heat transfer advantages of the microchannel reactor, reducing the phenomenon of intense localized reactions due to component inhomogeneity, decreasing side reactions, and improving production safety and product yield. Patent CN117123162A discloses a sleeve-type microchannel reactor, including a supporting base, a drive mechanism, a reactor body, and a drive platform. This solves the problem of existing technologies relying on the flow between various media to achieve ideal temperature conditions. However, this reactor has a complex structure, leading to difficulties in reactor operation and potential blockages. Patent CN117861564A proposes a method for synergistic catalysis in series of homogeneous and multiphase reactors. This method connects a multiphase tubular fixed-bed reactor with a homogeneous batch reactor or bubble column reactor in series. It utilizes the advantages of multiphase catalytic gas-solid reaction to solve the problems of catalyst recovery in homogeneous systems and catalyst metal loss during the flash evaporation process of homogeneous reactions. However, this reactor has problems such as difficulty in replacing the catalyst and the inability to recover the catalyst.

[0006] In summary, current microchannel reactors have certain problems, such as susceptibility to clogging during use and the significant increase in reaction costs due to frequent reactor replacements. Therefore, this invention provides a microreactor that incorporates a sieve plate and utilizes controllable channels for filling porous materials, applicable to hydrogen transfer reactions. Summary of the Invention

[0007] To address the existing technical problems, the present invention aims to provide a method for hydrogen transfer reaction using a microreactor device, which solves the problems of non-recyclable homogeneous reaction catalysts, high requirements for catalyst structure, uniform particle size and mechanical strength in fixed beds or fluidized beds, high cost of traditional microchannel reactors, difficulty in catalyst loading, easy clogging, and high production cost.

[0008] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0009] A method for hydrogen transfer reaction using a microreactor device, the microreactor device comprising a liquid pipeline system, a gas pipeline system, a microreactor, and a cooling and product collection system; the top of the microreactor is connected to both the liquid pipeline system and the gas pipeline system, and the bottom of the microreactor is connected to the cooling and product collection system; wherein:

[0010] The microreactor is a packed microreactor tube, which includes a tube body filled with a replaceable catalyst. The upper and lower ends of the tube body are respectively equipped with filter screens for trapping catalysts of different sizes. The filter screens at both ends are connected to material inlet / outlet connectors via fasteners to stabilize the catalyst. A blade ring and a sealing ring are sequentially arranged between the fasteners and the tube body from top to bottom.

[0011] The method includes: filling the reaction tube of a microreactor with a Pt / Al2O3 catalyst; first, introducing an inert gas to purge the air from the microreactor and maintaining the pressure inside the packed microreactor at 0.1-0.5 MPa; then, continuously pumping a feed liquid consisting of a mixture of an alcohol compound of Formula I and an amine compound of Formula II into the microreactor for reaction, setting the reaction temperature to 175-200℃ and the feed liquid space velocity to 0.1 h⁻¹. -1 -0.4h -1 After the reaction liquid flows out of the microreactor, it enters the cooling and product collection system for collection, and the product shown in Formula III is obtained.

[0012]

[0013] R1 is selected from C1-C6 alkyl, substituted alkyl or benzyl, wherein the substituted alkyl has 1-6 carbon atoms and the substituent is C1-C4 alkoxy;

[0014] R2 is selected from phenyl or substituted phenyl, wherein the substituted phenyl has one or more substituents, each substituent being independently selected from C1-C6 alkyl or halogen.

[0015] Furthermore, the particle size of the catalyst ranges from 0.1 to 1000 micrometers, and the pore size of the filter sieve plate is adjustable to stabilize the catalyst and prevent catalyst loss. It is suitable for catalysts that are difficult to form, have low mechanical strength, and have uneven particle size.

[0016] Furthermore, the inner diameter of the tube is 0.1-10 mm. Even further, the inner diameter of the tube can be one of 0.25 mm, 0.32 mm, 0.53 mm, 2.1 mm, 3.0 mm, or 4.6 mm.

[0017] Furthermore, the fastener is a connecting screw.

[0018] Furthermore, the liquid piping system includes a raw material tank and a feed pump connected via a liquid pipeline, and the feed pump is connected to the top of the microreactor via the liquid pipeline.

[0019] Furthermore, the gas pipeline system includes a gas cylinder and a gas flow meter, which are connected by a gas pipeline, and the gas flow meter is connected to the top of the microreactor via the gas pipeline.

[0020] The Pt / Al2O3 catalyst described in this invention can be a commercially available product.

[0021] Furthermore, the volume ratio of alcohols to amines in the raw material liquid is 1:1-3.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] (1) Compared with fixed-bed and other tubular reactors, which require redesign and remolding of powdered catalysts, the microreactor of the present invention can be compatible with catalysts with uneven particle size distribution through the sieve plate, and can carry out the reaction without molding, and has a smaller liquid (gas) holding capacity.

[0024] (2) The present invention can reduce the problems of large liquid hold-up, long-term contact between raw materials and catalyst, and long residence time in batch reactors, which lead to increased side reactions and reduced selectivity.

[0025] (3) Compared with traditional microchannel reactors, the microreactor of the present invention is simple to pack catalyst, less prone to clogging, and has low production cost.

[0026] (4) The microreactor described in this invention can regulate materials through the channel structure to increase the mixing effect of materials in the hydrogen transfer reaction. At the same time, the sieve plate can improve the mass transfer efficiency of the reactor. By using the microreactor to carry out the hydrogen transfer reaction, a higher product yield was obtained. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the packing-type microreactor described in this invention. Figure 1 ;

[0028] Figure 2 This is a schematic diagram of the packing-type microreactor described in this invention. Figure 2 ;

[0029] Figure 3 This is an enlarged schematic diagram of the connecting screws and filter in the microreactor structure;

[0030] Figure 4 This is an overall schematic diagram of the microreactor device described in this invention.

[0031] The accompanying diagrams are labeled as follows:

[0032] 1-Liquid piping system; 2-Gas piping system; 3-Microreactor; 4-Cooling and product collection system; 11-Raw material tank; 12-Feed pump; 21-Gas cylinder; 22-Gas flow meter; 31-Pipe body; 32-Porous packing; 33-Filter sieve plate; 34-Material inlet / outlet connector; 35-Fixed component; 36-Blade ring; 37-Sealing ring.

[0033] Figure 5 This is a gas chromatogram of the product of Example 1.

[0034] Figure 6 This is the gas chromatogram of the product of Comparative Example 1-1.

[0035] Figure 7 This is the gas chromatogram of the products of Comparative Examples 1-2.

[0036] Figure 8 This is a gas chromatogram of the product from Example 2.

[0037] Figure 9 This is the gas chromatogram of the product of Comparative Example 2-1.

[0038] Figure 10 This is the gas chromatogram of the product of Comparative Example 2-2.

[0039] Figure 11 This is a gas chromatogram of the product of Example 3.

[0040] Figure 12 This is the gas chromatogram of the product of Comparative Example 3-1.

[0041] Figure 13 This is the gas chromatogram of the product of Comparative Example 3-2.

[0042] Figure 14 This is a particle size distribution diagram of the fresh Pt / Al2O3 catalyst used in the examples and comparative examples.

[0043] Figure 15 This is a particle size distribution diagram of the Pt / Al2O3 catalyst after molding treatment.

[0044] Figure 16 This is a particle size distribution diagram of the Pt / Al2O3 catalyst after long-term use and pulverization following the molding process. Detailed Implementation

[0045] The technical solution of the present invention will be further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited thereto:

[0046] refer to Figures 1 to 4 The microreactor device used in this embodiment of the invention includes a liquid pipeline system 1, a gas pipeline system 2, a microreactor 3, and a cooling and product collection system 4; the top of the microreactor 3 is connected to both the liquid pipeline system 1 and the gas pipeline system 2, and the bottom of the microreactor 3 is connected to the cooling and product collection system 4; wherein:

[0047] The microreactor 3 is a packed microreactor tube, which includes a tube body 31 filled with a replaceable catalyst 32. The upper and lower ends of the tube body 31 are respectively provided with filter screens 33 for retaining catalysts of different sizes. The filter screens 33 at both ends are connected to material inlet / outlet connectors 34 via fixing members 35 to stabilize the catalyst. A blade ring 36 and a sealing ring 37 are sequentially arranged between the fixing member 35 and the tube body 31 from top to bottom.

[0048] The fastener 35 is a connecting screw;

[0049] The liquid pipeline system 1 includes a raw material tank 11 and a feed pump 12, which are connected by a liquid pipeline and the feed pump 12 is connected to the top of the microreactor 3 by a liquid pipeline.

[0050] The gas pipeline system 2 includes a gas cylinder 21 and a gas flow meter 22. The gas cylinder 21 and the gas flow meter 22 are connected by a gas pipeline, and the gas flow meter 22 is connected to the top of the microreactor 3 through the gas pipeline 2.

[0051] Example 1:

[0052] This microreactor was used to conduct the reaction of ethylene glycol monopropyl ether with the intermediate (Z)-N-(2,6-diethylphenyl)-2-propoxyethane-1-imine in the synthesis of 2,6-diethylaniline.

[0053] A mixture of ethylene glycol monopropyl ether and 2,6-diethylaniline (V 乙二醇单正丙醚 :V 2,6二乙基苯胺 A 1:3 ratio of Pt / Al2O3 catalyst (Shanghai Aladdin Biochemical Technology Co., Ltd.) was used as the reaction raw material. A 150-mesh Pt / Al2O3 catalyst was loaded into tube 31. Tube 31 was 28 cm long, with an inner diameter of 2.1 mm, and the filter sieve plate 33 had a pore size of 10 micrometers. First, the pressure reducing valve in gas pipeline system 2 was opened, and the nitrogen valve was opened. A continuous and stable flow rate of 1 m³ / g was introduced under the control of the flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 3 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter. 3 When the nitrogen flow rate reaches 0.4 MPa, the flow meter and nitrogen valve are closed. The feed liquid is continuously pumped into the microreactor via a feed pump for preheating and mixing before entering the reaction zone for continuous reaction. The feed space velocity is set to 2 h⁻¹. -1 The reaction was carried out at a pressure of 1.0 MPa and a temperature of 200 °C. After three hours of reaction, the reaction liquid was collected from the collection tank for gas chromatography analysis. The analysis showed that the selectivity of the target product was 94.35% and the conversion rate was 94%.

[0054] Comparative Example 1-1:

[0055] The reaction of ethylene glycol mono-n-propyl ether with 2,6-diethylaniline to synthesize the intermediate (Z)-N-(2,6-diethylphenyl)-2-propoxyethane-1-imine was carried out using a batch reactor.

[0056] A mixture of ethylene glycol monopropyl ether and 2,6-diethylaniline (V 乙二醇单正丙醚 :V 2,6二乙基苯胺 A 1:3 ratio of Pt / Al₂O₃ catalyst (150 mesh) was used as the reactant in a 316L batch reactor. The nitrogen valve was opened, and a continuous, stable flow rate of 1 m³ / min was introduced, controlled by a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 3 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter. 3Nitrogen gas was supplied at a flow rate of [flow rate] / min. When the pressure gauge reading reached 1.0 MPa, the flow meter and nitrogen valve were closed. (Shanghai Aladdin Biochemical Technology Co., Ltd.) The liquid holdup was 75%, and the reaction temperature was set to 200℃. After ten hours, the reaction liquid was collected in a collection tank and analyzed by gas chromatography. The analysis showed that the selectivity of the target product was 84.35%, and the conversion rate was 81%.

[0057] Comparative Examples 1-2:

[0058] The reaction of ethylene glycol mono-n-propyl ether with 2,6-diethylaniline as a synthesis intermediate (Z)-N-(2,6-diethylphenyl)-2-propoxyethane-1-imine was carried out using a fixed-bed apparatus.

[0059] The Pt / Al2O3 catalyst was shaped into tablets and then sieved to 20-40 mesh. The shaped catalyst was then filled into a reaction tube to form a packed bed. First, the pressure reducing valve in the gas pipeline system was opened, and the nitrogen valve was opened. The flow rate was continuously and stably increased to 2 m³ / g under the control of a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 6 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter. 3 When the pressure gauge reading reaches 0.5 MPa, stop the flow meter and close the nitrogen valve. Maintain a liquid holdup of 70%. Adjust the catalyst bed and vaporization chamber temperatures to a stable 200°C. Start the liquid pump to pump the mixture of ethylene glycol monopropyl ether and 2,6-diethylaniline (V... 乙二醇单正丙醚 :V 2,6二乙基苯胺 =1:3) was introduced into the reaction system, and samples were taken after ten hours of continuous reaction. The target product selectivity was 85.35% and the conversion rate was 87%. After a long-term reaction, pulverization was found after 15 hours.

[0060] Example 2:

[0061] This microreactor device was used to synthesize N-benzylaniline from aniline and benzyl alcohol.

[0062] A mixture of aniline and benzyl alcohol (V) 苯胺 :V 苯甲醇 A 1:1 ratio of Pt / Al2O3 catalyst (Shanghai Aladdin Biochemical Technology Co., Ltd.) was used as the reaction raw material. A 150-mesh Pt / Al2O3 catalyst was loaded into tube 31. This tube was 28 cm long, had an inner diameter of 2.1 mm, and the filter screen had a pore size of 10 micrometers. First, the pressure reducing valve in gas pipeline system 2 was opened, and the nitrogen valve was opened. A continuous and stable flow rate of 1 m³ / g was introduced, controlled by a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 3 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter.3 When the nitrogen flow rate reaches 0.4 MPa, the flow meter and nitrogen valve are closed. The feed liquid is continuously pumped into the microreactor via a feed pump for preheating and mixing before entering the reaction zone for continuous reaction. The feed space velocity is set to 2 h⁻¹. -1 The reaction was carried out at a pressure of 1.0 MPa and a temperature of 200 °C. After three hours, the reaction solution was collected from the collection tank for gas chromatography analysis. The analysis showed that the selectivity of the target product was 95.24% and the conversion rate was 91%.

[0063] Comparative Example 2-1:

[0064] The reaction of aniline and benzyl alcohol to synthesize N-benzylaniline was carried out using a batch reactor.

[0065] A mixture of aniline and benzyl alcohol (V) 苯胺 :V 苯甲醇 A 1:1 ratio of Pt / Al2O3 catalyst (powdered catalyst purchased from Aladdin Company) was used as the reaction raw material and loaded into a batch reactor. The nitrogen valve was opened, and the flow rate was continuously and stably increased to 1 m³ / g using a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 3 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter. 3 Nitrogen gas was supplied at a flow rate of 1 / min. When the pressure gauge reading reached 0.1 MPa, the flow meter and nitrogen valve were turned off. The liquid holdup was 75%, and the reaction temperature was set to 200℃. After ten hours, the reaction liquid was collected in a collection tank and analyzed by gas chromatography. The analysis showed that the selectivity of the target product was 75.24%, and the conversion rate was 82%.

[0066] Comparative Example 2-2:

[0067] The reaction of aniline and benzyl alcohol to synthesize N-benzylaniline was carried out using a fixed-bed apparatus.

[0068] The Pt / Al2O3 catalyst was shaped into tablets using a pressing method and then sieved to 20-40 mesh. The shaped catalyst was then filled into the reaction tube to form a packed bed. First, the pressure reducing valve in the gas pipeline system was opened, and the nitrogen valve was opened. The flow rate was continuously and stably increased to 1.5 m³ / g, controlled by a flow meter. 3 Nitrogen gas is introduced at a rate of 6 m³ / min. After 6 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 6 m³ / min using a flow meter. 3 Flow nitrogen at a rate of / min. When the pressure gauge reading reaches 0.5 MPa, turn off the flow meter and close the nitrogen valve. Maintain a liquid holdup of 70%. Adjust the temperature of the catalyst bed and vaporization chamber to a stable 200°C. Start the liquid pump to pump the mixture of aniline and benzyl alcohol (V... 苯胺 :V 苯甲醇=1:1) is introduced into the reaction system, and samples are taken after ten hours of continuous reaction, such as Figure 6 Analysis and calculations showed that the selectivity of the target product was 85.43% and the conversion rate was 87%. After a long-term reaction of 15 hours, pulverization was observed.

[0069] Example 3:

[0070] This microreactor device was used to synthesize 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline from methyl ethyl aniline and 1-methoxypropanol.

[0071] A mixture of 2-methyl-6-ethylaniline and 1-methoxy-2-propanol (V 甲乙基苯胺 :V 1-甲氧基丙醇 A 2:1 ratio of Pt / Al2O3 (powdered catalyst purchased from Aladdin Company) was used as the reaction raw material. A 150-mesh Pt / Al2O3 catalyst was loaded into tube 31. This microreactor is 28 cm long, has an inner diameter of 2.1 mm, and the filter sieve has a pore size of 10 micrometers. First, the pressure reducing valve in gas pipeline system 2 was opened, and the nitrogen valve was opened. A continuous and stable flow rate of 1 m³ / g was introduced, controlled by a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 3 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter. 3 When the nitrogen flow rate reaches 0.4 MPa, the flow meter and nitrogen valve are closed. The feed liquid is continuously pumped into the microreactor via a feed pump for preheating and mixing before entering the reaction zone for continuous reaction. The feed space velocity is set to 2 h⁻¹. -1 The reaction was carried out at a pressure of 1.0 MPa and a temperature of 200℃. After three hours, the reaction liquid was collected from the collection tank for gas chromatography analysis. The analysis showed that the selectivity of the target product was 93.32%, and the conversion rate was 93%.

[0072] Comparative Example 3-1:

[0073] The reaction of methyl ethyl aniline with 1-methoxypropanol to synthesize 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline was carried out using a batch reactor.

[0074] A mixture of methyl ethyl aniline and 1-methoxypropanol (V 甲乙基苯胺 :V 1-甲氧基丙醇 A 2:1 ratio of Pt / Al2O3 (powdered catalyst purchased from Aladdin Company) was used as the reaction raw material. A 150-mesh Pt / Al2O3 catalyst was charged into a batch reactor. The nitrogen valve was opened, and a continuous and stable flow rate of 1 m³ / g was controlled by a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 3 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 5 m³ / min using a flow meter. 3Nitrogen gas was supplied at a flow rate of 0.4 MPa / min. The flow meter and nitrogen valve were then closed when the pressure gauge reading reached 0.4 MPa. The liquid holdup was 75%, and the reaction temperature was set to 200°C. After ten hours, the reaction solution was collected in a collection tank and analyzed by gas chromatography. The analysis showed a selectivity of 80.32% and a conversion rate of 84% for the target product.

[0075] Comparative Example 3-2:

[0076] A fixed-bed apparatus was used to synthesize 2-ethyl-N-(2-methoxy-1-methylethyl)-6-methylaniline from methyl ethyl aniline and 1-methoxypropanol.

[0077] The Pt / Al2O3 catalyst is shaped into tablets and then sieved to 20-40 mesh. The shaped catalyst is then filled into the reaction tube to form a packed bed. First, the pressure reducing valve in the gas pipeline system is opened, and then the nitrogen valve is opened. The nitrogen gas is continuously and stably introduced at a flow rate of 1.5 m³ / h, controlled by a flow meter. 3 Nitrogen gas is introduced at a rate of 1 / min. After 5 seconds, the air is mostly expelled. At this point, the pressure reducing valve is closed, creating a sealed space. The flow rate is then adjusted to 1.5 m³ / min using a flow meter. 3 Flow rate of nitrogen is 1 / min. When the pressure gauge reading reaches 0.5 MPa, the flow meter and nitrogen valve are closed. The liquid holdup is 70%. The temperature of the catalyst bed and vaporization chamber is adjusted and stabilized at 200℃. The liquid pump is started to pump the mixture of raw materials methyl ethyl aniline and 1-methoxypropanol (V... 甲乙基苯胺 :V 1-甲氧基丙醇 =2:1) ​​was introduced into the reaction system, and samples were taken after ten hours of continuous reaction. The target product selectivity was 83.32% and the conversion rate was 77%. After a long-term reaction, pulverization was found after 15 hours.

Claims

1. A method for hydrogen transfer reaction using a microreactor device, characterized in that: The microreactor device includes a liquid piping system, a gas piping system, a microreactor, and a cooling and product collection system; the top of the microreactor is connected to both the liquid piping system and the gas piping system, and the bottom of the microreactor is connected to the cooling and product collection system; wherein: The microreactor is a packed microreactor tube, which includes a tube body filled with a replaceable catalyst. The upper and lower ends of the tube body are respectively equipped with filter screens for trapping catalysts of different sizes. The filter screens at both ends are connected to material inlet / outlet connectors via fasteners to stabilize the catalyst. A blade ring and a sealing ring are sequentially arranged between the fasteners and the tube body from top to bottom. The method includes: filling the reaction tube of a microreactor with a Pt / Al2O3 catalyst; first, introducing an inert gas to purge the air from the microreactor and maintaining the pressure inside the packed microreactor at 0.1-0.5 MPa; then, continuously pumping a feed liquid consisting of an alcohol compound of Formula I and an amine compound of Formula II into the microreactor for reaction, setting the reaction temperature to 175-200℃ and the feed liquid space velocity to 0.1 h⁻¹. -1 -0.4h -1 After the reaction liquid flows out of the microreactor, it enters the cooling and product collection system for collection, and the product shown in Formula III is obtained. R1 is selected from C1-C6 alkyl, substituted alkyl or benzyl, wherein the substituted alkyl has 1-6 carbon atoms and the substituent is C1-C4 alkoxy; R2 is selected from phenyl or substituted phenyl, wherein the substituted phenyl has one or more substituents, each substituent being independently selected from C1-C6 alkyl or halogen.

2. The method as described in claim 1, characterized in that: The catalyst has a particle size range of 0.1-1000 micrometers, and the pore size of the filter sieve plate is adjustable to stabilize the catalyst.

3. The method as described in claim 1, characterized in that: The inner diameter of the tube is 0.1-10 mm.

4. The method as described in claim 1, characterized in that: The fastener is a connecting screw.

5. The method as described in claim 1, characterized in that: The liquid piping system includes a raw material tank and a feed pump connected by a liquid pipeline, and the feed pump is connected to the top of the microreactor via the liquid pipeline.

6. The method as described in claim 1, characterized in that: The gas pipeline system includes a gas cylinder and a gas flow meter, which are connected by a gas pipeline, and the gas flow meter is connected to the top of the microreactor via the gas pipeline.

7. The method according to any one of claims 1-6, characterized in that: The volume ratio of alcohols to amines in the feed liquid is 1:1-3.

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