Micro-channel reactor for preparing 3-nitro-N-ethyl carbazole and use method of micro-channel reactor

Abstract

The invention provides a micro-channel reactor for preparing 3-nitro-N-ethyl carbazole. The micro-channel reactor comprises a supporting cabinet, a supporting panel is arranged at the top of the supporting cabinet, a sealing chamber is arranged at the top of the supporting panel, and an evaporation pipe of a refrigeration assembly is arranged in the sealing chamber; a support frame body is arranged in the sealing chamber; a plurality of mixing channels are installed on the surface of the supporting frame body, outlets are formed in the tops of the side faces of the mixing channels, inlets are formed in the bottoms of the side faces of the mixing channels, and the outlets and the inlets of every two adjacent mixing channels are communicated through second connecting pipes; a liquid outlet pipe is connected to an outlet in the top of the rightmost mixing channel. When the reaction kettle is used, a plurality of mixing channels are connected in series to form a relatively long reaction channel, and the mixing channels are cooled by the evaporation pipes, so that the reaction temperature is moderately kept at the optimal temperature, and reactants flowing through the mixing channels are long in residence time and can be fully mixed in the flowing process.

Description

Technical Field

[0001] The invention relates to the technical field of microchannel reactors, in particular to a microchannel reactor for preparing 3-nitro-N-ethylcarbazole and a use method thereof. Background Art

[0002] 3-Nitro-N-ethylcarbazole is mainly used as an intermediate for medicines and dyes. This compound has important application value in the chemical industry1. Its chemical properties include its appearance as a yellow crystalline powder, a melting point between 128-130°C, and a boiling point of 362.3°C. Its molecular formula is C14H12N2O2, and its molecular weight is 240.2623. In terms of application, it is mainly used to prepare intermediates for medicines and dyes. As an important organic synthetic raw material, it can participate in the production process of a variety of chemicals and provide key ingredients for the pharmaceutical and dye industries.

[0003] 3-Nitro-N-ethylcarbazole can be prepared by nitration reaction, and nitration reaction is a continuous exothermic process. The existing microchannel reactor does not have the ability to quickly cool down, so that the temperature of the reactants in the microchannel cannot be effectively dissipated, resulting in high reaction temperature, which affects the production process. To this end, we propose a microchannel reactor for preparing 3-nitro-N-ethylcarbazole and a method for using the same. Summary of the invention

[0004] Aiming at the disadvantage that the existing microchannel reactor for preparing 3-nitro-N-ethylcarbazole is easy to heat up, the present invention provides a microchannel reactor for preparing 3-nitro-N-ethylcarbazole, which has the advantages that the mixing channel is cooled by an evaporation tube and the cooling speed is fast, thereby solving the problems raised in the above background technology.

[0005] The technical solution of the present invention is achieved as follows: a microchannel reactor for preparing 3-nitro-N-ethylcarbazole, comprising a support cabinet, a support panel is provided on the top of the support cabinet, a sealed chamber is provided on the top of the support panel, and an evaporation tube of a refrigeration component is arranged in the sealed chamber; a support frame is provided in the sealed chamber; a plurality of mixing channels are installed on the surface of the support frame, an outlet is provided on the top of the side of the mixing channel, an inlet is provided on the bottom of the side, and the outlet and the inlet between two adjacent mixing channels are respectively connected through a second connecting pipe; a liquid outlet is connected to the outlet at the top of the rightmost mixing channel, and a first connecting pipe is connected to the inlet at the bottom of the leftmost mixing channel; and at least two feed pipes are provided at one end of the first connecting pipe away from the mixing channel.

[0006] Preferably, the sealed chamber includes a protective cover, which covers the supporting frame, and a supporting frame is provided inside the protective cover, and the supporting frame and the bottom of the protective cover are respectively connected to the supporting panel; an opening is provided on one side of the protective cover, and a sealing door is rotatably provided on one side of the opening, and an observation window is provided in the middle of the sealing door.

[0007] Preferably, the support frame includes a mounting plate, both sides of which are arranged on the supporting panel through brackets; the evaporating tube is bent and arranged on the surface of the mounting plate, and the mixing channel is located at the side of the evaporating tube.

[0008] Preferably, connecting seats are respectively provided on one side of both ends of the mixing channel close to the evaporating tube, the connecting seats are installed on the surface of the mounting plate, and a gap is provided between the mixing channel and the evaporating tube; side baffles are respectively vertically connected to the two sides of the mounting plate, the mixing channel is located between the two side baffles, and a sealing plate is detachably connected to the side of the two side baffles away from the mounting plate.

[0009] Preferably, a Venturi mixer is installed on the first connecting pipe between the feed pipe and the inlet, and the Venturi mixer is arranged on the support panel through a mounting frame; the Venturi mixer is arranged in a protective shell, the bottom of the protective shell is arranged on the support panel, and the feed pipe extends from the protective shell to the outside.

[0010] Preferably, a sealing cover is detachably provided on the top of the mixing channel; a spiral baffle is placed in the mixing channel, and a channel is provided in the middle of the spiral baffle.

[0011] Preferably, the bottom of the mixing channel is connected to a sewage pipe, and a valve is provided at the end of the sewage pipe.

[0012] Preferably, a controller is provided in the supporting cabinet, a temperature sensor is provided on the surface of the mounting plate, and the controller is connected to the temperature sensor and the evaporation tube respectively.

[0013] Preferably, the number of the supporting frames is at least two, and each feed pipe is provided with a flow sensor, which is connected to the controller.

[0014] The present invention also provides a method for using a microchannel reactor for preparing 3-nitro-N-ethylcarbazole, comprising the following steps:

[0015] Step 1, the reactants for preparing 3-nitro-N-ethylcarbazole are stored in respective preparation tanks, the preparation tanks are connected to delivery pumps through pipelines, the delivery pumps are connected to respective feed pipes, and the respective reactants are passed into a venturi mixer through the delivery pumps for preliminary mixing;

[0016] Step 2: The reactants mixed by the venturi mixer enter the mixing channel through the first connecting pipe, and the reactants move in each mixing channel, and the moving reactants contact the spiral baffle to make the reactants evenly mixed;

[0017] Step 3: The evaporator cools the mixing channel to keep the mixing channel at a moderate reaction temperature, so that the reactants can be fully mixed and fully reacted at a suitable temperature when traveling in the mixing channel;

[0018] Step 4: Collect the reactants discharged from each liquid outlet pipe.

[0019] Compared with the prior art, when the present invention is used, the reactants mixed by the venturi mixer enter the mixing channel through the first connecting pipe, the reactants move in each mixing channel, and the moving reactants contact the spiral baffle, so that the reactants are evenly mixed. Moreover, since a plurality of mixing channels are connected in series to form a longer reaction channel, and the mixing channel is cooled by the evaporation tube, the reaction temperature is moderate to maintain the optimal temperature, and the reactants flowing through each mixing channel have a long residence time. During the flow process, each reactant can be fully mixed to make the reaction more complete. Finally, the reactants flow out from the liquid outlet pipe, and the operator can collect the reactants flowing out of the liquid outlet pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0022] Figure 2 It is a schematic diagram of the internal structure of the present invention.

[0023] Figure 3 The structure of the support frame of the present invention is shown in FIG. Figure 1 .

[0024] Figure 4 The structure of the support frame of the present invention is schematically shown in FIG. Figure 2 .

[0025] Figure 5 It is a cross-sectional view of the present invention.

[0026] Figure 6 It is a schematic diagram of the structure of the mixing channel of the present invention.

[0027] In the figure: support cabinet 1, support panel 2, feed pipe 3, protective shell 4, protective cover 5, sealing door 6, mounting frame 7, drain pipe 8, sealing plate 9, bracket 10, liquid outlet pipe 11, second connecting pipe 12, support frame 13, Venturi mixer 14, mixing channel 15, spiral baffle 16, first connecting pipe 17, sealing cover 18, connecting seat 19, mounting plate 20, side baffle 21, evaporation tube 22, outlet 23, inlet 24, temperature sensor 25. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Reference Figures 1 to 6 The present invention provides a technical solution: a microchannel reactor for preparing 3-nitro-N-ethylcarbazole, comprising a support cabinet 1, a refrigeration component is arranged in the support cabinet 1, and the refrigeration component is the same as the refrigeration component in the air conditioner and the refrigerator, a support panel 2 is arranged on the top of the support cabinet 1, and a support frame is arranged on the surface of the support panel 2, such as Figure 3 As shown, the support frame includes a mounting plate 20 , and two sides of the mounting plate 20 are arranged on the supporting panel 2 through brackets 10 .

[0030] A plurality of mixing channels 25 are installed on the surface of the support frame, such as Figure 4 As shown, the mixing channel 25 is specifically located on the surface of the supporting panel 2, the evaporation tube 22 of the refrigeration assembly is bent and arranged on the surface of the mounting plate 20, and the mixing channel 25 is located on the side of the evaporation tube 22 and there is a certain gap between the two to avoid direct contact between the evaporation tube 22 and the mixing channel 25, so that when the evaporation tube 22 is used to absorb the heat generated during the reaction, the reaction temperature is controlled between 30-55°C;

[0031] The top of the side of the mixing channel 25 is provided with an outlet 23, the bottom of the side of the mixing channel 25 is provided with an inlet 24, and the outlets 23 and inlets 24 between two adjacent mixing channels 25 are connected through the second connecting pipe 12, so that the mixing channels 25 form a reaction channel with a long length and connected at the end;

[0032] like Figure 4 As shown, the outlet 23 at the top of the rightmost mixing channel 25 is connected to the liquid outlet pipe 11, and the inlet 24 at the bottom of the leftmost mixing channel 25 is connected to the first connecting pipe 17, and at least two feed pipes 3 are arranged at one end of the first connecting pipe 17 away from the mixing channel 25. A venturi mixer 14 is installed on the first connecting pipe 17 between the feed pipe 3 and the inlet 24, and the venturi mixer 14 is arranged on the support panel 2 through the mounting frame 7;

[0033] The specific operation process is that it should be noted that there are at least two reactants for preparing 3-nitro-N-ethylcarbazole, and the number of feed pipes 3 corresponds to the number of reactants, that is, one reactant corresponds to one feed pipe 3. Therefore, during production, each reactant is introduced from the feed pipe 3, specifically by an infusion pump, and each reactant of the feed pipe 3 is introduced into the venturi mixer 14 for preliminary mixing, and then the reactant flows into the mixing channel 15 along the first connecting pipe 17. Since a plurality of mixing channels 15 are connected in series to form a longer reaction channel, and the mixing channel 15 is cooled by the evaporation tube, the reactant retention time flowing through each mixing channel 15 is long, and in the process of flowing, each reactant can be fully mixed to make the reaction more complete. Finally, the reactant flows out from the liquid outlet pipe 11, and the operator collects the reactant flowing out of the liquid outlet pipe 11.

[0034] Among them, a protective cover 5 is also provided on the top of the support panel 2, and the protective cover 5 covers the support frame therein. A support frame 13 is provided inside the protective cover 5, and the support frame 13 is used to strengthen the support strength of the protective cover 5. The support frame 13 and the bottom of the protective cover 5 are respectively connected to the support panel 2. An opening is provided on one side of the protective cover 5, and a sealing door 6 is rotatably provided on one side of the opening, and an observation window is provided in the middle of the sealing door 6. The situation inside the protective cover can be directly observed through the observation window. The observation window is a double-layer insulation structure, and insulation materials, such as insulation boards, are provided on the inner wall of the protective cover 5. The protective cover 5 and the support frame 13 form a sealed chamber, which can not only protect the mixing channel 15, but most importantly, can keep the mixing channel 15 warm to avoid rapid changes in the heat emitted by the evaporating tube;

[0035] like Figure 1 As shown, the venturi mixer 14 is arranged in the protective shell 4 , the bottom of the protective shell 4 is arranged on the supporting panel 2 , and the feed pipe 3 extends from the protective shell 4 to the outside. The arranged protective shell 4 can protect the venturi mixer 14 .

[0036] Furthermore, the mixing channel 15 is detachable, that is, connecting seats 19 are respectively provided on one side of both ends of the mixing channel 15 close to the evaporation tube 22, and the connecting seats 19 are installed on the surface of the mounting plate 20, and a gap is provided between the mixing channel 15 and the evaporation tube 22;

[0037] In order to better concentrate the cold air of the evaporating tube around the mixing channel 15, side baffles 21 are vertically connected to both sides of the mounting plate 20, and the mixing channel 15 is located between the two side baffles 21. The two side baffles 21 are detachably connected to a sealing plate 9 on the side away from the mounting plate 20. The sealing plate 9 is connected to the side baffles 21 by a lock or bolts, and the side baffles 21 and the sealing plate 9 form an insulating chamber, which wraps the mixing channel 15, so that the cold air of the evaporating tube is concentrated in the chamber, and the mixing channel 15 is continuously cooled.

[0038] Furthermore, a sealing cover 18 is detachably provided on the top of the mixing channel 15, and the two are connected by threads or flanges. A spiral baffle 16 is placed in the mixing channel 15, and a channel is provided in the middle of the spiral baffle 16. Figure 6 As shown, when the reactants flow upward from the bottom of the mixing channel 15, the spiral baffle 16 will contact the reactants, allowing the reactants to tumble quickly while flowing, thereby increasing the mixing efficiency of the reactants. In addition, the spiral baffle 16 is directly placed inside the mixing channel 15 through the opening at the top of the mixing channel 15, which is convenient for installation and disassembly.

[0039] Furthermore, because the reactants enter from the bottom of the mixing channel 15 and finally flow out from the top, this increases the tumbling degree of the reactants. However, when production is stopped, some reactants will remain in the mixing channel 15. Therefore, in order to avoid this situation, the bottom of the mixing channel 15 is connected to the drain pipe 8, and a valve is provided at the end of the drain pipe 8. Therefore, when production is stopped, the liquid outlet pipe 11 can be kept unobstructed, and then the valve can be opened to drain the residual reactants in each mixing channel 15.

[0040] Furthermore, a controller is provided in the support cabinet 1, and the controller is a PLC logic controller or a host. A temperature sensor is provided on the surface of the mounting plate 20, and the controller is respectively connected to the temperature sensor and the evaporation tube 22, so that the evaporation tube can realize automatic temperature control.

[0041] Furthermore, the number of the supporting frames is at least two, one supporting frame is a reaction device, and multiple supporting frames are multiple reaction devices, such as Figure 2 As shown, multiple reaction devices working simultaneously can increase production efficiency, and each feed pipe 3 is provided with a flow sensor, which is connected to the controller to facilitate monitoring of the flow of each feed pipe 3.

[0042] The present invention also proposes a method for using a microchannel reactor for preparing 3-nitro-N-ethylcarbazole, comprising the following steps:

[0043] Step 1, the reactants for preparing 3-nitro-N-ethylcarbazole are stored in respective preparation tanks, the preparation tanks are connected to delivery pumps through pipelines, the delivery pumps are connected to respective feed pipes, and the respective reactants are passed into a venturi mixer through the delivery pumps for preliminary mixing;

[0044] Step 2: The reactants mixed by the venturi mixer enter the mixing channel through the first connecting pipe, and the reactants move in each mixing channel, and the moving reactants contact the spiral baffle to make the reactants evenly mixed;

[0045] Step 3: The evaporator cools the mixing channel to keep the mixing channel at a moderate reaction temperature, so that the reactants can be fully mixed and fully reacted at a suitable temperature when traveling in the mixing channel;

[0046] Step 4: Collect the reactants discharged from each liquid outlet pipe.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A microchannel reactor for preparing 3-nitro-N-ethylcarbazole, comprising a support cabinet (1), a refrigeration assembly is arranged in the support cabinet (1), and a support panel (2) is arranged on the top of the support cabinet (1), characterized in that: A sealed chamber is provided on the top of the support panel (2), and an evaporation pipe (22) of the refrigeration component is arranged in the sealed chamber; A support frame is provided in the sealed chamber; and, A plurality of mixing channels (25) are installed on the surface of the support frame, an outlet (23) is provided at the top of the side of the mixing channel (25), and an inlet (24) is provided at the bottom of the side, and the outlets (23) and inlets (24) between two adjacent mixing channels (25) are respectively connected through a second connecting pipe (12); the outlet (23) at the top of the rightmost mixing channel (25) is connected to a liquid outlet pipe (11), and the inlet (24) at the bottom of the leftmost mixing channel (25) is connected to a first connecting pipe (17); At least two feed pipes (3) are provided at one end of the first connecting pipe (17) away from the mixing channel (25).

2. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 1, characterized in that: The sealed chamber comprises a protective cover (5), wherein the protective cover (5) covers the support frame body, a support frame (13) is arranged inside the protective cover (5), and the support frame (13) and the bottom of the protective cover (5) are respectively connected to the support panel (2); An opening is provided on one side of the protective cover (5), a sealing door (6) is rotatably provided on one side of the opening, and an observation window is provided in the middle of the sealing door (6).

3. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 1, characterized in that: The support frame comprises a mounting plate (20), and two sides of the mounting plate (20) are arranged on the supporting panel (2) through brackets (10); The evaporation tube (22) is bent and arranged on the surface of the mounting plate (20), and the mixing channel (15) is located at the side of the evaporation tube (22).

4. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 3, characterized in that: Connecting seats (19) are respectively provided on one side of both ends of the mixing channel (15) close to the evaporating tube (22); the connecting seats (19) are mounted on the surface of the mounting plate (20), and a gap is provided between the mixing channel (15) and the evaporating tube (22); Side baffles (21) are vertically connected to both sides of the mounting plate (20), the mixing channel (15) is located between the two side baffles (21), and a sealing plate (9) is detachably connected to one side of the two side baffles (21) away from the mounting plate (20).

5. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 4, characterized in that: A venturi mixer (14) is installed on the first connecting pipe (17) between the feed pipe (3) and the inlet (24), and the venturi mixer (14) is arranged on the support panel (2) through a mounting frame (7); The venturi mixer (14) is arranged in the protective shell (4), the bottom of the protective shell (4) is arranged on the supporting panel (2), and the feed pipe (3) extends from the protective shell (4) to the outside.

6. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to any one of claims 1 to 5, characterized in that: A sealing cover (18) is detachably provided on the top of the mixing channel (15); A spiral baffle (16) is placed in the mixing channel (15), and a channel is arranged in the middle of the spiral baffle (16).

7. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 6, characterized in that: The bottom of the mixing channel (15) is connected to the sewage pipe (8), and a valve is provided at the end of the sewage pipe (8).

8. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 7, characterized in that: A controller is arranged in the supporting cabinet (1), a temperature sensor is arranged on the surface of the mounting plate (20), and the controller is connected to the temperature sensor and the evaporation tube (22) respectively.

9. The microchannel reactor for preparing 3-nitro-N-ethylcarbazole according to claim 8, characterized in that: The number of the supporting frames is at least two, and each feed pipe (3) is provided with a flow sensor, which is connected to a controller.

10. A method for using the microchannel reactor for preparing 3-nitro-N-ethylcarbazole as claimed in claim 9, characterized in that: The steps include: Step 1, the reactants for preparing 3-nitro-N-ethylcarbazole are stored in respective preparation tanks, the preparation tanks are connected to delivery pumps through pipelines, the delivery pumps are connected to respective feed pipes, and the respective reactants are passed into a venturi mixer through the delivery pumps for preliminary mixing; Step 2: The reactants mixed by the venturi mixer enter the mixing channel through the first connecting pipe, and the reactants move in each mixing channel, and the moving reactants contact the spiral baffle to make the reactants evenly mixed; Step 3: The evaporator cools the mixing channel to keep the mixing channel at a moderate reaction temperature, so that the reactants can be fully mixed and fully reacted at a suitable temperature when traveling in the mixing channel; Step 4: Collect the reactants discharged from each liquid outlet pipe.

Images