CN115155462A - Method and device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation - Google Patents

Method and device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation Download PDF

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CN115155462A
CN115155462A CN202210889608.9A CN202210889608A CN115155462A CN 115155462 A CN115155462 A CN 115155462A CN 202210889608 A CN202210889608 A CN 202210889608A CN 115155462 A CN115155462 A CN 115155462A
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micro
catalyst
heat exchange
exchange medium
mixing
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鄢冬茂
司阳
刘嵩
纪璐
安亭旺
魏微
明卫星
张建军
孙文瑄
王瀚德
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Shenyang Research Institute of Chemical Industry Co Ltd
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Shenyang Research Institute of Chemical Industry Co Ltd
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J8/00—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes
    • B01J8/02—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds
    • B01J8/0207—Chemical or physical processes in general, conducted in the presence of fluids and solid particles; Apparatus for such processes with stationary particles, e.g. in fixed beds the fluid flow within the bed being predominantly horizontal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/30—Micromixers
    • B01F33/301—Micromixers using specific means for arranging the streams to be mixed, e.g. channel geometries or dispositions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F33/00—Other mixers; Mixing plants; Combinations of mixers
    • B01F33/80—Mixing plants; Combinations of mixers
    • B01F33/836—Mixing plants; Combinations of mixers combining mixing with other treatments
    • B01F33/8362—Mixing plants; Combinations of mixers combining mixing with other treatments with chemical reactions
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/90—Heating or cooling systems
    • B01F35/92—Heating or cooling systems for heating the outside of the receptacle, e.g. heated jackets or burners
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/90—Heating or cooling systems
    • B01F2035/99—Heating

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  • Chemical Kinetics & Catalysis (AREA)
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  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention relates to the field of production and preparation of 2, 4-diaminoanisole, in particular to a method and a device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation based on a micro packed bed. Pd (OH) catalyst 2 the/C is filled in a micro packed bed reactor of the device in claim 1; replacing air in the device by nitrogen, adding a reaction material, and reacting the reaction material with hydrogen at 25-125 ℃ and 1.0-3.0MPa in the presence of the nitrogen to prepare the 2, 4-diaminoanisole. Compared with the conventional kettle type reactor, the device of the invention adopts the micro packed bed reactor, has larger gas-liquid-solid three-phase contact area and higher heat and mass transfer capacity, and can more accurately realizeThe reaction process is controlled, and the reaction period is shortened.

Description

Method and device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation
Technical Field
The invention relates to the field of production and preparation of 2, 4-diaminoanisole, in particular to a method and a device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation based on a micro packed bed.
Background
2, 4-diaminoanisole is an important organic synthesis intermediate, and is widely applied to the fields of fine chemicals such as dye and pigment, medicine, pesticide and the like.
The 2, 4-diaminoanisole is prepared by hydrogenating and reducing 2, 4-dinitroanisole. 2, 4-dinitroanisole contains two unsaturated nitro groups, and complete conversion to 2, 4-diaminoanisole is difficult to achieve because the conversion of the first nitro group (electron withdrawing group) to the amine group (electron donating group) reduces the electronic defect in the ring and prevents further reduction of the second nitro group. The traditional technology for industrially producing 2, 4-diaminoanisole is as follows: raney nickel is used as a catalyst, hydrogen is used as a reducing agent, and a hydrogenation reduction reaction is carried out in a batch autoclave to obtain the product. However, raney nickel is harsh in use conditions and high in danger, and a certain amount of waste water and solid waste are generated in the reaction process, so that the environmental pollution is serious. The hydrogenation reaction of 2, 4-dinitroanisole is realized by adopting a Pd/C catalyst, but the reaction time of the process is long, and the number of times of the catalyst is used is small.
Many studies have shown that satisfactory results are difficult to achieve with processes in which aromatic dinitro compounds are modified in batch reactors using only catalysts. The patent CN108218728A discloses a preparation method of 2, 4-diaminoanisole, which uses Pd/Al 2 O 3 The method is characterized in that kettle-type serial continuous hydrogenation is carried out for the catalyst, and the catalyst is separated by membrane filtration, so that the method has high production efficiency and product quality, but the catalyst needs to be continuously supplemented in the reaction process, and complicated and time-consuming sedimentation filtration operation is also needed. Patent CN111302949A discloses a process for preparing phenylenediamine by a micro-reaction technique, wherein nitro-aromatics to be reduced, a solvent, a catalyst and hydrogen are metered and then continuously fed into a hydrogenation microreactor to perform hydrogenation reduction reaction, so that the yield is high. However, the catalyst entering the microreactor in the form of suspension is prone to sedimentation and blockage of pipelines and requires complicated catalyst separation and recovery operations. Patent CN113402395A provides a microreactor based on a fixed bed for the hydrogenation of m-dinitrobenzene, but with a lower yield of m-phenylenediamine. And the gas-liquid material is heated after entering the pipeline of the micro packed bed, and needs a certain time to reach the reaction temperature.
Disclosure of Invention
Aiming at the technical problems and the defects in the field, the invention aims to provide the method and the device for preparing the 2, 4-diaminoanisole by continuous catalytic hydrogenation based on the micro packed bed, which have high production efficiency, high completeness and environmental friendliness.
In order to achieve the purpose, the invention adopts the technical scheme that:
a device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation comprises a nitrogen input pipeline, a hydrogen input pipeline, a three-way valve (4), a liquid material input pipeline, a micro-mixing heat exchanger (9), a micro-packed bed reactor (11) and a gas-liquid separator (13), wherein the micro-mixing heat exchanger (9) is provided with a gas material inlet (901), a liquid material inlet (902) and a gas-liquid mixture outlet (905), and the nitrogen input pipeline, the hydrogen input pipeline and the gas material inlet (901) are respectively connected with corresponding ports on the three-way valve (4),the liquid material inlet (902) is connected with a liquid material input pipeline, and the gas-liquid mixture outlet (905), the micro packed bed reactor (11) and the gas-liquid separator (13) are sequentially connected in series through pipelines; 2, 4-dinitroanisole is dissolved in an organic solvent to prepare liquid material and the liquid material is input through the liquid material input pipeline, a catalyst cavity and a heat exchange medium cavity are arranged inside the micro packed bed reactor (11), the heat exchange medium cavity is arranged around the catalyst cavity, and Pd (OH) is arranged in the catalyst cavity 2 A catalyst/C.
The micro-mixing heat exchanger (9) is internally provided with a mixing channel (906) and a heat exchange medium arranged around the mixing channel (906), the gas material inlet (901) and the liquid material inlet (902) are both communicated with the input end of the mixing channel (906), and the output end of the mixing channel (906) is communicated with the gas-liquid mixture outlet (905).
The mixing channel (906) in the micro-mixing heat exchanger (9) comprises a first mixing section and a second mixing section, wherein the first mixing section comprises a flow dividing unit (9061) and a converging unit (9062) which are arranged in a staggered mode, a first flow dividing block (9064) and a second flow dividing block (9063) are arranged in the second mixing section in a staggered mode, and the second flow dividing block (9063) is larger than the first flow dividing block (9064).
And a first heat exchange medium inlet (903) and a first heat exchange medium outlet (904) are arranged on the micro-mixing heat exchanger (9), and the first heat exchange medium inlet (903) and the first heat exchange medium outlet (904) are communicated with a cavity for bearing heat exchange media in the micro-mixing heat exchanger (9).
One end of the micro packed bed reactor (11) is provided with a reactor inlet (1101), the other end of the micro packed bed reactor is provided with a reactor outlet (1106), the first end part of the catalyst cavity is connected with the reactor inlet (1101), a first sieve plate (1102) is arranged in the first end part, the second end part of the catalyst cavity is connected with the reactor outlet (1106), and a second sieve plate (1105) is arranged in the second end part.
And a second heat exchange medium inlet (1103) and a second heat exchange medium outlet (1104) are arranged on the micro packed bed reactor (11), and the second heat exchange medium inlet (1103) and the second heat exchange medium outlet (1104) are communicated with the heat exchange medium cavity.
Be equipped with gas mass flow controller (5) and manometer (6) on the connecting line between three-way valve (4) and little mixed heat exchanger (9), be equipped with high-pressure pump (7) and check valve (8) on the liquid material input pipeline, be equipped with a back pressure valve (12) on vapour and liquid separator (13), on the pipeline between little mixed heat exchanger (9) and little packed bed reactor (11) and all be equipped with thermometer (10) on the pipeline between little packed bed reactor (11) and vapour and liquid separator (13).
The method for preparing 2, 4-diaminoanisole by using the device through continuous catalytic hydrogenation comprises the step of adding a catalyst Pd (OH) 2 the/C is filled in a micro packed bed reactor of the device of claim 1; replacing air in the device by nitrogen, adding a reaction material, and reacting the reaction material with hydrogen at 25-125 ℃ and 1.0-3.0MPa in the presence of the nitrogen to prepare the 2, 4-diaminoanisole.
The reaction material is 2, 4-dinitroanisole dissolved in an organic solvent, wherein the final concentration of the 2, 4-dinitroanisole in the reaction material is 0.2-0.6mol/L; the organic solvent is tetrahydrofuran or ethyl acetate;
the Pd (OH) 2 Pd (OH) in/C catalyst 2 7 percent of the catalyst, the carrier is micro-nano spherical active carbon, the average grain diameter is 0.6mm, the average grain diameter of the catalyst is 600nm, and the specific surface area of the catalyst is not less than 800m 2 /g。
The reaction materials are added into the reactor at the flow rate of 0.4-1.6 ml/min; hydrogen is added into the reactor at a flow rate of 40-70 ml/min.
The invention has the advantages and positive effects that:
1. compared with a conventional kettle type reactor, the device provided by the invention has the advantages that a micro packed bed reactor is adopted, the gas-liquid-solid three-phase contact area is larger, the heat and mass transfer capacity is higher, the reaction process can be controlled more accurately, and the reaction period is shortened.
2. The device adopts the micro-mixing heat exchanger, and has high-efficiency gas-liquid mixing capacity and high-efficiency preheating capacity. High-efficient gas-liquid mixture can the material gas-liquid evenly distributed and avoid follow-up because the local overheat that the material mixing is inhomogeneous leads to preheats with high efficiency makes the gas-liquid mixture material reach required temperature fast.
3. The invention adopts Pd (OH) loaded on micro-nano spherical active carbon particles 2 The catalyst has high activity, stable performance and high hydrogenation selectivity, and the method is applied to the hydrogenation of 2, 4-dinitroanisole, the conversion rate is 100 percent, the selectivity is more than 97 percent, and the best can reach 99.53 percent.
4. The method has simple process flow, the catalyst is fixed in the micro packed bed reactor, and the subsequent catalyst separation operation is not needed. Realizes continuous hydrogenation, improves the production efficiency and reduces the labor intensity. The reaction process has no three wastes, and is beneficial to resource saving and environmental protection.
Drawings
FIG. 1 is a schematic view of the structure of the present invention,
figure 2 is a schematic external view of the micro-hybrid heat exchanger of figure 1,
figure 3 is a schematic diagram of the internal structure of the micro-hybrid heat exchanger of figure 2,
FIG. 4 is a schematic external view of the micro packed bed reactor of FIG. 1,
fig. 5 is a schematic view of the internal structure of the micro packed bed reactor of fig. 4.
The system comprises a high-pressure nitrogen cylinder 1, a high-pressure hydrogen cylinder 2, a gas path control ball valve 3, a three-way valve 4, a gas mass flow controller 5, a pressure gauge 6, a high-pressure pump 7, a one-way valve 8, a micro-mixing heat exchanger 9, a gas material inlet 901, a liquid material inlet 902, a first heat exchange medium inlet 903, a first heat exchange medium outlet 904, a gas-liquid mixture outlet 905, a mixing channel 906, a flow dividing unit 9061, a converging unit 9062, a second flow dividing block 9063, a first flow dividing block 9064, a communicating channel 907, a thermometer 10, a micro-packed bed reactor 11, a reactor inlet 1101, a first sieve plate 1102, a second heat exchange medium inlet 1103, a second heat exchange medium outlet 1104, a second sieve plate 1105, a reactor outlet 1106, a back pressure valve 12 and a gas-liquid separator 13.
FIG. 6 is an electron micrograph of a catalyst according to an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Example 1
As shown in fig. 1 to 5, the present invention includes a nitrogen input pipeline, a hydrogen input pipeline, a three-way valve 4, a liquid material input pipeline, a micro-mixing heat exchanger 9, a micro-packed bed reactor 11, and a gas-liquid separator 13, wherein as shown in fig. 2 to 3, the micro-mixing heat exchanger 9 is provided with a gas material inlet 901, a liquid material inlet 902, and a gas-liquid mixture outlet 905, a mixing channel 906 and a heat exchange medium filled around the mixing channel 906 are provided inside the micro-mixing heat exchanger 9, the gas material inlet 901 and the liquid material inlet 902 are both communicated with an input end of the mixing channel 906, an output end of the mixing channel 906 is communicated with the gas-liquid mixture outlet 905, as shown in fig. 1, the nitrogen input pipeline, the hydrogen input pipeline, and the gas material inlet 901 are respectively connected with corresponding ports on the three-way valve 4, the liquid material inlet 902 is connected with the liquid material input pipeline, and the gas-liquid mixture outlet 905, the micro-liquid packed bed reactor 11, and the gas-liquid separator 13 are sequentially connected in series through pipelines.
As shown in fig. 3, the mixing channel 906 in the micro-mixing heat exchanger 9 includes a first mixing section and a second mixing section, wherein the first mixing section includes a diversion unit 9061 and a convergence unit 9062 which are arranged in a staggered manner, in this embodiment, the diversion unit 9061 includes two diversion channels arranged in a diamond shape, and after the material flows into the diversion unit 9061, the material is divided into two parts and flows along different diversion channels, and then the two parts are converged again and flow out to enter a single channel of the next convergence unit 9062, so that the material is continuously diverted and converged, and the material mixing is further realized. Because the first mixing section is used for primarily mixing the liquid material and the gas material, the invention realizes the large-amplitude flow distribution and convergence of the two materials through the flow distribution unit 9061 and the convergence unit 9062 which are arranged in a staggered manner, thereby ensuring the full mixing.
As shown in fig. 3, a first shunting block 9064 and a second shunting block 9063 are arranged in the second mixing section in a staggered manner, in this embodiment, the first shunting block 9064 and the second shunting block 9063 are both circular, the diameter of the second shunting block 9063 is larger than that of the first shunting block 9064, and when a material passes through the first shunting block 9064 and the second shunting block 9063 when the second mixing section flows, the material sequentially flows through a gap between two sides of the first shunting block 9064 and a pipe wall of the second mixing section and a gap between two sides of the second shunting block 9063 and a pipe wall of the second mixing section, so that the material is continuously shunted and converged, and is further mixed. Because the materials are fully mixed in the first mixing section and then enter the second mixing section, the invention realizes the shunting and convergence of the materials with relatively small amplitude and changed amplitude at the same time by utilizing the first shunting block 9064 and the second shunting block 9063 with different diameters so as to ensure the stable mixing and the full heat exchange of the materials in the second mixing section.
As shown in fig. 3, a communication channel 907 is disposed in the micro-hybrid heat exchanger 9, and the gas material inlet 901 and the liquid material inlet 902 are respectively communicated with the input end of the mixing channel 906 through different communication channels 907, and the communication channels 907 are disposed in the heat exchange medium.
As shown in fig. 2 to 3, a first heat exchange medium inlet 903 and a first heat exchange medium outlet 904 are arranged on the micro-hybrid heat exchanger 9, and both the first heat exchange medium inlet 903 and the first heat exchange medium outlet 904 are communicated with a cavity for accommodating a heat exchange medium in the micro-hybrid heat exchanger 9. In this embodiment, the heat exchange medium is high-temperature water.
As shown in fig. 4 to 5, a catalyst cavity is arranged inside the micro packed bed reactor 11, a Pd (OH) 2/C catalyst is arranged in the catalyst cavity, in the Pd (OH) 2/C catalyst, the proportion of Pd (OH) 2 is 7%, the carrier is spherical activated carbon, the average particle size is 0.6nm, and the specific surface area of the catalyst is 712.3m 2 /g。
As shown in fig. 4 to 5, one end of the micro packed bed reactor 11 is provided with a reactor inlet 1101, the other end is provided with a reactor outlet 1106, the first end of the catalyst cavity is connected to the reactor inlet 1101, the first end is provided with a first sieve plate 1102, the second end of the catalyst cavity is connected to the reactor outlet 1106, the second end is provided with a second sieve plate 1105, and the first sieve plate 1102 and the second sieve plate 1105 are used for preventing the catalyst from flowing out. As shown in fig. 1, the reactor inlet 1101 communicates with the gas-liquid mixture outlet 905 of the micro-mixing heat exchanger 9 through a pipe, and the reactor outlet 1106 communicates with the gas-liquid separator 13.
As shown in fig. 4 to 5, a heat exchange medium cavity is arranged in the micro packed bed reactor 11, the heat exchange medium cavity surrounds the catalyst cavity, a second heat exchange medium inlet 1103 and a second heat exchange medium outlet 1104 are arranged on the micro packed bed reactor 11, and the second heat exchange medium inlet 1103 and the second heat exchange medium outlet 1104 are both communicated with the heat exchange medium cavity.
As shown in fig. 1, the input end of the nitrogen input pipeline is connected with a high-pressure nitrogen cylinder 1, the output end of the nitrogen input pipeline is connected with a corresponding port of the three-way valve 4, the input end of the hydrogen input pipeline is connected with a high-pressure hydrogen cylinder 2, the output end of the hydrogen input pipeline is connected with a corresponding port of the three-way valve 4, and the nitrogen input pipeline and the hydrogen input pipeline are both provided with gas path control ball valves 3.
As shown in fig. 1, a gas mass flow controller 5 and a pressure gauge 6 are arranged on a connecting pipeline between the three-way valve 4 and the micro-mixing heat exchanger 9, the gas mass flow controller 5 and the pressure gauge 6 are used for controlling the flow and pressure of gas materials input into the micro-mixing heat exchanger 9, and the gas mass flow controller 5 and the pressure gauge 6 are all known in the art and are commercially available products.
As shown in fig. 1, a high-pressure pump 7 and a check valve 8 are disposed on the liquid material input pipeline, wherein the high-pressure pump 7 is used for pumping the liquid material into the micro-mixing heat exchanger 9, the high-pressure pump 7 and the check valve 8 are both known in the art and are commercially available products, in this embodiment, 2, 4-dinitroanisole is dissolved in an organic solvent to prepare a liquid material, and the organic solvent may be tetrahydrofuran or ethyl acetate.
As shown in fig. 1, thermometers 10 are disposed on the pipeline between the micro-hybrid heat exchanger 9 and the micro-packed bed reactor 11 and the pipeline between the micro-packed bed reactor 11 and the gas-liquid separator 13 for detecting the temperature of the input or output material, and the thermometers 10 are well known in the art and are commercially available products.
As shown in fig. 1, a back pressure valve 12 is provided on the gas-liquid separator 13, and the back pressure valve 12 is a commercially available product and is well known in the art.
Example 2:
the method comprises the following steps: using the apparatus described in the above example, pd (OH) 2 The catalyst/C is filled in a micro packed bed reactor, the filling amount of the catalyst is 1g, the catalyst is filled to the middle part of a pipeline, and the rest is filled with a blank carrier (micro-nano spherical active carbon).
The catalyst Pd (OH) 2 the/C is prepared by a deposition-precipitation method, wherein Pd (OH) 2 Pd (OH) in/C catalyst 2 7 percent of the catalyst, the carrier is micro-nano spherical active carbon with the average particle size of 600nm and the specific surface area of 712.3m 2 (see FIG. 6).
Step two: and then opening a nitrogen input pipeline under normal pressure, setting the nitrogen flow rate to be 100mL/min for 3min of replacement, blowing and discharging air in the pipeline by using nitrogen, protecting the catalyst under the nitrogen atmosphere, and checking the tightness of the system.
Dissolving 2, 4-dinitroanisole in ethyl acetate to prepare a reaction solution with the concentration of 0.2 mol/L.
Step four: and opening the cold-hot circulation all-in-one machine to set the reaction temperature to be 60 ℃.
Step five: setting the pressure value of the back pressure valve to be 2.0MPa, opening the hydrogen input pipeline, opening the hydrogen valve, and setting the flow parameter of the gas mass flow controller to be 50mL/min.
Step six: setting the flow of the high-pressure pump to be 0.5mL/min, starting the high-pressure pump when the temperature of the cold-hot circulation all-in-one machine reaches 60 ℃, and injecting the liquid material prepared in the third step into the reaction system.
Step seven: and after the system is stabilized, collecting a sample from the liquid outlet of the gas-liquid separator.
After the reaction is finished, the catalyst and the reactor are flushed by methanol, the methanol is discharged by nitrogen purging, and the catalyst is protected under the nitrogen atmosphere. The reaction product of this example was analyzed by gas chromatography: the reaction conversion rate is 100%, and the selectivity is as follows: 97.62 percent.
Example 3:
the difference from the embodiment 2 is that:
the method comprises the following steps: using the apparatus described in the above example, pd (OH) 2 The catalyst/C is filled in a micro packed bed reactor, the filling amount of the catalyst is 1g, the catalyst is filled to the middle part of a pipeline, and the rest is filled with a blank carrier (micro-nano spherical active carbon).
Step two: and then opening a nitrogen input pipeline under normal pressure, setting the nitrogen flow rate to be 100mL/min for 3min of replacement, blowing and discharging air in the pipeline by using nitrogen, protecting the catalyst under the nitrogen atmosphere, and checking the tightness of the system.
Dissolving 2, 4-dinitroanisole in tetrahydrofuran to prepare a reaction solution with the concentration of 0.2 mol/L.
Step four: and opening the cold-hot circulation all-in-one machine to set the reaction temperature to be 60 ℃.
Step five: setting the pressure value of the back pressure valve to be 2MPa, opening the hydrogen input pipeline, opening the hydrogen valve, and setting the flow parameter of the gas mass flow controller to be 96mL/min.
Step six: setting the flow rate of the high-pressure pump to be 1.6mL/min, starting the high-pressure pump when the temperature of the cold-hot circulation all-in-one machine reaches the set temperature of 60 ℃, and injecting the liquid material prepared in the third step into the reaction system.
Step seven: and after the system is stabilized, collecting a sample from the liquid outlet of the gas-liquid separator.
After the reaction is finished, the catalyst and the reactor are flushed by methanol, the methanol is discharged by purging with nitrogen, and the catalyst is protected under the nitrogen atmosphere. The reaction product of this example was analyzed by gas chromatography: the reaction conversion rate is 100%, and the selectivity is as follows: 98.98 percent.
Example 4:
the difference from the embodiment 2 is that:
the method comprises the following steps: using the apparatus described in the above example, pd (OH) 2 The catalyst/C is filled in a micro packed bed reactor, the filling amount of the catalyst is 0.5g, the catalyst is filled to the middle part of a pipeline, and the rest is filled with a blank carrier(micro nano spherical activated carbon) filling.
Step two: and then opening a nitrogen input pipeline under normal pressure, setting the nitrogen flow rate to be 100mL/min for 3min of replacement, blowing and discharging air in the pipeline by using nitrogen, protecting the catalyst under the nitrogen atmosphere, and checking the tightness of the system.
Dissolving 2, 4-dinitroanisole in tetrahydrofuran to prepare a reaction solution with the concentration of 0.6 mol/L.
Step four: and opening the cold-hot circulation all-in-one machine to set the reaction temperature to be at the temperature of C.
Step five: setting the pressure value of the back pressure valve to be 1.0MPa, opening the hydrogen input pipeline, opening the hydrogen valve, and setting the flow parameter of the gas mass flow controller to be 60mL/min.
Step six: setting the flow rate of the high-pressure pump to be 1.2mL/min, starting the high-pressure pump when the temperature of the cold-hot circulation all-in-one machine reaches the set temperature of 55 ℃, and injecting the liquid material prepared in the third step into the reaction system.
Step seven: and after the system is stabilized, collecting a sample from the liquid outlet of the gas-liquid separator.
After the reaction is finished, the catalyst and the reactor are flushed by methanol, the methanol is discharged by purging with nitrogen, and the catalyst is protected under the nitrogen atmosphere. The reaction product of this example was analyzed by gas chromatography: the reaction conversion rate is 100%, and the selectivity is as follows: 98.16 percent.
Example 5:
the difference from the embodiment 2 is that:
the method comprises the following steps: using the apparatus described in the above example, pd (OH) 2 The catalyst/C is filled in a micro packed bed reactor, the filling amount of the catalyst is 1.0g, the catalyst is filled to the middle part of a pipeline, and the rest is filled with a blank carrier (micro-nano spherical active carbon).
Step two: and then opening a nitrogen input pipeline under normal pressure, setting the nitrogen flow rate to be 100mL/min for 3min of replacement, blowing and discharging air in the pipeline by using nitrogen, protecting the catalyst under the nitrogen atmosphere, and checking the tightness of the system.
Dissolving 2, 4-dinitroanisole in tetrahydrofuran to prepare a reaction solution with the concentration of 0.2 mol/L.
Step four: and opening the cold-hot circulation all-in-one machine to set the reaction temperature to be 55 ℃.
Step five: setting the pressure value of the back pressure valve to be 2MPa, opening the hydrogen input pipeline, opening the hydrogen valve, and setting the flow parameter of the gas mass flow controller to be 60mL/min.
Step six: setting the flow rate of a high-pressure pump to be 1mL/min, starting the high-pressure pump when the temperature of the cold-hot circulation integrated machine reaches the set temperature of 55 ℃, and injecting the liquid material prepared in the third step into the reaction system.
Step seven: and after the system is stabilized, collecting a sample from the liquid outlet of the gas-liquid separator.
After the reaction is finished, the catalyst and the reactor are flushed by methanol, the methanol is discharged by purging with nitrogen, and the catalyst is protected under the nitrogen atmosphere. The reaction product of this example was analyzed by gas chromatography: the reaction conversion rate is 100%, and the selectivity is as follows: 99.53 percent.
Example 6:
the difference from the example 2 is that:
the method comprises the following steps: using the apparatus described in the above example, pd (OH) 2 The catalyst/C is filled in a micro packed bed reactor, the filling amount of the catalyst is 1.0g, the catalyst is filled to the middle part of a pipeline, and the rest is filled with a blank carrier (micro-nano spherical active carbon).
Step two: and then opening a nitrogen input pipeline under normal pressure, purging and discharging air in the pipeline by using nitrogen, protecting the catalyst in the nitrogen atmosphere, and checking the tightness of the system.
Dissolving 2, 4-dinitroanisole in tetrahydrofuran to prepare a reaction solution with the concentration of 0.2 mol/L.
Step four: and opening the cold-hot circulation all-in-one machine to set the reaction temperature to be 55 ℃.
Step five: setting the pressure value of the back pressure valve to be 3MPa, opening the hydrogen input pipeline, opening the hydrogen valve, and setting the flow parameter of the gas mass flow controller to be 60mL/min.
Step six: setting the flow rate of the high-pressure pump to be 1mL/min, starting the high-pressure pump when the temperature of the cold-hot circulation all-in-one machine reaches the set temperature of 55 ℃, and injecting the liquid material prepared in the third step into the reaction system.
Step seven: and after the system is stabilized, collecting a sample from the liquid outlet of the gas-liquid separator.
After the reaction is finished, the catalyst and the reactor are flushed by methanol, the methanol is discharged by purging with nitrogen, and the catalyst is protected under the nitrogen atmosphere. The reaction product of this example was analyzed by gas chromatography: the reaction conversion rate is 100%, and the selectivity is as follows: 98.07 percent.

Claims (10)

1. A device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation is characterized in that: the device comprises a nitrogen input pipeline, a hydrogen input pipeline, a three-way valve (4), a liquid material input pipeline, a micro-mixing heat exchanger (9), a micro-packed bed reactor (11) and a gas-liquid separator (13), wherein the micro-mixing heat exchanger (9) is provided with a gas material inlet (901), a liquid material inlet (902) and a gas-liquid mixture outlet (905), the nitrogen input pipeline, the hydrogen input pipeline and the gas material inlet (901) are respectively connected with corresponding ports on the three-way valve (4), the liquid material inlet (902) is connected with the liquid material input pipeline, and the gas-liquid mixture outlet (905), the micro-packed bed reactor (11) and the gas-liquid separator (13) are sequentially connected in series through pipelines; 2, 4-dinitroanisole is dissolved in an organic solvent to prepare liquid material and the liquid material is input through the liquid material input pipeline, a catalyst cavity and a heat exchange medium cavity are arranged inside the micro packed bed reactor (11), the heat exchange medium cavity is arranged around the catalyst cavity, and Pd (OH) is arranged in the catalyst cavity 2 a/C catalyst.
2. The apparatus for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation according to claim 1, characterized in that: the micro-mixing heat exchanger (9) is internally provided with a mixing channel (906) and a heat exchange medium arranged around the mixing channel (906), the gas material inlet (901) and the liquid material inlet (902) are both communicated with the input end of the mixing channel (906), and the output end of the mixing channel (906) is communicated with the gas-liquid mixture outlet (905).
3. The apparatus for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation according to claim 2, characterized in that: a mixing channel (906) in the micro-mixing heat exchanger (9) comprises a first mixing section and a second mixing section, wherein the first mixing section comprises a flow dividing unit (9061) and a converging unit (9062) which are arranged in a staggered mode, a first flow dividing block (9064) and a second flow dividing block (9063) are arranged in the second mixing section in a staggered mode, and the second flow dividing block (9063) is larger than the first flow dividing block (9064).
4. The apparatus for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation according to claim 2, characterized in that: and a first heat exchange medium inlet (903) and a first heat exchange medium outlet (904) are arranged on the micro-mixing heat exchanger (9), and the first heat exchange medium inlet (903) and the first heat exchange medium outlet (904) are communicated with a cavity for containing a heat exchange medium in the micro-mixing heat exchanger (9).
5. The apparatus for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation according to claim 1, characterized in that: one end of the micro packed bed reactor (11) is provided with a reactor inlet (1101), the other end of the micro packed bed reactor is provided with a reactor outlet (1106), the first end part of the catalyst cavity is connected with the reactor inlet (1101), a first sieve plate (1102) is arranged in the first end part, the second end part of the catalyst cavity is connected with the reactor outlet (1106), and a second sieve plate (1105) is arranged in the second end part.
6. The apparatus for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation according to claim 1, characterized in that: and a second heat exchange medium inlet (1103) and a second heat exchange medium outlet (1104) are arranged on the micro packed bed reactor (11), and the second heat exchange medium inlet (1103) and the second heat exchange medium outlet (1104) are communicated with the heat exchange medium cavity.
7. The apparatus for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation according to claim 1, characterized in that: be equipped with gas mass flow controller (5) and manometer (6) on the connecting pipeline between three-way valve (4) and the micro-mixing heat exchanger (9), be equipped with high-pressure pump (7) and check valve (8) on the liquid material input pipeline, be equipped with a back pressure valve (12) on vapour and liquid separator (13), on the pipeline between micro-mixing heat exchanger (9) and micro packed bed reactor (11) and all be equipped with thermometer (10) on the pipeline between micro packed bed reactor (11) and vapour and liquid separator (13).
8. A method for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation by using the device of claim 1, which is characterized in that: catalyst Pd (OH) 2 the/C is filled in a micro packed bed reactor of the device of claim 1; replacing air in the device by nitrogen, adding a reaction material, and reacting the reaction material with hydrogen at 25-125 ℃ and 1.0-3.0MPa in the presence of the nitrogen to prepare the 2, 4-diaminoanisole.
9. The method of claim 8, wherein: the reaction material is 2, 4-dinitroanisole dissolved in an organic solvent, wherein the final concentration of the 2, 4-dinitroanisole in the reaction material is 0.2-0.6mol/L; the organic solvent is tetrahydrofuran or ethyl acetate;
the Pd (OH) 2 Pd (OH) in/C catalyst 2 7 percent of the catalyst, the carrier is spherical active carbon, the average grain diameter is 0.6mm, and the specific surface area of the catalyst is not less than 800m 2 /g。
10. The method of claim 8, wherein: the reaction materials are added into the reactor at the flow rate of 0.4-1.6 ml/min; hydrogen is added into the reactor at a flow rate of 40-70 ml/min.
CN202210889608.9A 2022-07-27 2022-07-27 Method and device for preparing 2, 4-diaminoanisole by continuous catalytic hydrogenation Pending CN115155462A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116555024A (en) * 2023-07-07 2023-08-08 吉林凯莱英医药化学有限公司 Continuous synthesis device and method for unnatural amino acid

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116555024A (en) * 2023-07-07 2023-08-08 吉林凯莱英医药化学有限公司 Continuous synthesis device and method for unnatural amino acid
CN116555024B (en) * 2023-07-07 2023-09-19 吉林凯莱英医药化学有限公司 Continuous synthesis device and method for unnatural amino acid

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