A method and device for preparing p-nitrobenzyl alcohol

Abstract

The present invention relates to the technical field of p-nitrobenzyl alcohol preparation devices, and discloses a p-nitrobenzyl alcohol preparation method and device, including a kettle body. By coordinating a winding tube, an elastic strip, an annular plate, and a multi-stage electric push rod, it is possible to ensure that the catalyst is added according to the real-time monitoring of a liquid level meter during the addition process and accurately adjust the drop height. The multi-stage electric push rod flexibly changes according to the position of the liquid surface, so that the catalyst can be added at a suitable distance at different liquid levels, effectively preventing the problem of excessive local reaction caused by direct dropwise addition at a high position; multiple slots specially designed at the bottom of the annular plate further ensure that the catalyst is evenly distributed when dripping onto the liquid surface, thereby optimizing the entire chemical reaction process; the arrangement of the drainage rod, when the catalyst drips, the drainage rod cleverly guides the catalyst to flow smoothly into the liquid, ensuring that it is gently integrated into the reaction medium, promoting a more uniform and more effective chemical reaction.

Description

Technical Field

[0001] The present invention relates to the technical field of p-nitrobenzyl alcohol preparation devices, in particular to a p-nitrobenzyl alcohol preparation method and device. Background Art

[0002] p-Nitrobenzyl alcohol is an important organic synthesis intermediate commonly used in the synthesis of pharmaceuticals, dyes, and other fine chemicals. The preparation of p-nitrobenzyl alcohol involves the first bromination reaction: p-nitrotoluene and water are placed in a reactor, stirred, and heated. Bromine is then added dropwise. An initiator is then added dropwise in batches while maintaining the temperature. After the initiator is added, the reaction is continued at this temperature. The second step is whitening and hydrolysis: Sodium sulfite is added to the product obtained from the bromination reaction to whiten it. After stirring, water is added and the temperature is raised for reflux hydrolysis. After the hydrolysis is complete, sodium carbonate is added to adjust the pH. The third step is separation: Solvent is added to the product obtained from the whitening and hydrolysis reactions, and the mixture is allowed to stand to separate into an oily solution and an aqueous solution. The oily solution is concentrated, cooled, crystallized, and filtered to obtain the crude p-nitrobenzyl alcohol. During this preparation process, a stirred reactor is required to mix the various compounds and initiators to ensure uniform and efficient reaction.

[0003] However, the above-mentioned stirred reactor has the following disadvantages when used:

[0004] When adding initiators or other catalysts to a reactor, if the liquid level is low, the initiator dripped from the top may be concentrated in a specific area of the liquid surface. Even with a stirrer, this can cause a high concentration to form in that area due to the instantaneous initiator dripping. This triggers a localized, intense chemical reaction, generating significant heat and gas. This significantly accelerates the reaction rate in that area, while slowing down the reaction in other areas of the reactor, causing inconvenience. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method and apparatus for preparing p-nitrobenzyl alcohol to solve the problems raised in the background art. When the initiator is added dropwise, the dropping position can be adjusted according to the liquid level to avoid direct dripping from a high position.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solutions: A method and device for preparing p-nitrobenzyl alcohol, comprising a kettle body, a liquid level gauge connected to the kettle body, an annular cover fixedly connected to the inner wall of the kettle top, an elastic strip fixedly connected to the annular cover, an annular plate fixedly connected to the bottom of the elastic strip, a winding pipe fixedly connected to the top of the annular plate, a catalyst introduction container fixedly mounted on the top of the kettle body, an annular groove provided in the annular plate, a slot hole communicating with the annular groove provided at the bottom of the annular plate, a follower plate fixedly connected to the inner wall of the annular plate, a multi-stage electric push rod fixedly connected to the inner wall of the annular cover, an output end of the multi-stage electric push rod connected to the follower plate, a drainage member connected to the bottom of the annular plate, a liquid dispenser connected to the outer side of the kettle top, the liquid dispenser penetrating the inner wall of one end of the kettle body and connected to a sampling structure, a cleaning structure connected to the inner wall of the kettle body, and three groups of clamping members for connecting the sampling structure and the cleaning structure connected to the outer wall of the annular plate.

[0007] Furthermore, the guide member includes a plurality of guide rods, the guide rods are located below the slots, the guide rods are tilted, the tops of the guide rods are fixedly connected to mounting plates, and the mounting plates are fixedly mounted to the annular plate by bolts.

[0008] Furthermore, the sampling structure includes an upper liquid collection tube, which is sealed with the bottom of the liquid collector through the kettle top, a telescopic tube fixedly connected to the bottom of the upper liquid collection tube, and a lower liquid collection tube fixedly connected to the bottom of the telescopic tube.

[0009] Furthermore, the cleaning structure includes a cleaning ring, which is movably connected to the inner wall of the kettle body, a cleaning pipe is fixedly connected to the top of the cleaning ring, and a plurality of nozzles are fixedly connected to the outer wall of the cleaning ring. The cleaning pipe passes through the outside of the kettle top and is connected to a high-pressure water pump at one end.

[0010] Furthermore, two of the clamping parts are connected to the cleaning structure, and another clamping part is connected to the sampling structure. The three clamping parts all include an inner block fixedly connected to the inner wall of the annular plate, a movable groove is provided in the inner block, a movable block is slidably connected in the movable groove, the bottom surface of the movable block is fixedly connected to an extension plate, the end of the extension plate is fixedly connected to a clamping block, the inner walls of the liquid collection tube and the cleaning ring are fixedly connected to a fixed block, a clamping groove corresponding to the clamping block is provided in the fixed block, two of the clamping blocks are fixedly connected to the inner wall of the cleaning ring, and the other clamping block is fixedly connected to the outer wall of the liquid collection tube, and the outer wall of the annular cover is connected to a transmission assembly for driving the clamping block to engage.

[0011] Furthermore, the transmission assembly includes a main gear and a slave gear, a motor is fixedly connected to the outside of the top of the kettle body, the output end of the motor passes through the top of the kettle and is fixedly connected to the main gear, the outer wall of the annular cover is rotatably connected to the slave gear, the slave gear is meshed with the main gear, and the bottom surface of the slave gear is fixedly connected to vertical rods corresponding to the three extension plates, and the outer walls of the vertical rods are against the outer walls of the extension plates.

[0012] Furthermore, a spring is fixedly connected to the outer wall of one end of the moving block located in the moving groove, and the other end of the spring is against the inner wall of the moving groove.

[0013] Furthermore, a plurality of L-shaped mounting blocks are fixedly connected to the inner wall of the kettle body, the outer wall of the cleaning ring is slidably connected to the inner wall of the L-shaped mounting block, and the inner wall of the vertical plate of the L-shaped mounting block is fixedly connected to an extrusion strip.

[0014] Furthermore, the annular groove is arranged in an inverted trapezoidal shape.

[0015] A method for preparing p-nitrobenzyl alcohol, using the p-nitrobenzyl alcohol preparation device as described above for production, specifically comprises the following steps:

[0016] a. Add para-nitrotoluene and water into a reactor, stir and heat to 40~55°C, then add bromine dropwise, and add the initiator dropwise in batches under insulation conditions. After the initiator is added, continue the insulation reaction;

[0017] b. Sodium sulfite was added to the product obtained by the bromination reaction to whiten it. After stirring, water was added and the temperature was raised to 100 ° C for reflux hydrolysis. The hydrolysis time was 4 to 10 hours. After the hydrolysis was completed, the temperature was lowered to 70 ° C and sodium carbonate was added to adjust the pH value.

[0018] c. Add a solvent to the product obtained by the whitening and hydrolysis reactions, let it stand and separate into layers, and then obtain an oil solution layer and an aqueous solution layer. The oil solution layer is concentrated, cooled, crystallized, and filtered to obtain crude p-nitrobenzyl alcohol.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This method and device for preparing p-nitrobenzyl alcohol, through the coordinated arrangement of an annular cover, a winding tube, an elastic strip, an annular plate, and a multi-stage electric push rod, can ensure that the catalyst addition height can be accurately adjusted according to the real-time monitoring of the liquid level gauge during the catalyst addition process. The multi-stage electric push rod flexibly changes according to the position of the liquid surface, allowing the catalyst to be added at an appropriate distance at different liquid levels, effectively preventing the problem of excessive local reaction caused by direct dropwise addition from a high position. In addition, the multiple slots specially designed at the bottom of the annular plate further ensure that the catalyst is evenly distributed when dripping onto the liquid surface, thereby optimizing the entire chemical reaction process.

[0021] 2. This method and apparatus for preparing p-nitrobenzyl alcohol utilizes a drainage rod to cleverly guide the catalyst into the liquid as it drips, ensuring its gentle incorporation into the reaction medium. This design not only makes the catalyst addition process smoother and gentler, but also greatly optimizes the contact between the catalyst and reactants, promoting a more uniform and efficient chemical reaction. This significantly improves the overall catalytic process and further ensures reaction efficiency and product quality.

[0022] 3. This method and device for preparing p-nitrobenzyl alcohol ensures that the sampling tube will not be continuously immersed in the reaction medium when not sampling, thereby avoiding unnecessary contamination and the influence of chemical reactions on the sampling equipment, while also ensuring the accuracy of each sampling.

[0023] 4. This method and device for preparing p-nitrobenzyl alcohol, through the coordinated arrangement of the cleaning ring and the nozzle, can enable the inner wall of the kettle to be flushed by a high-pressure water source, thereby achieving a good cleaning effect on the inner wall of the kettle. The cleaning ring is pushed up and down by a multi-stage electric push rod, thereby achieving a better cleaning effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the overall three-dimensional structure of the present invention;

[0025] Figure 2 It is a schematic diagram of the three-dimensional cross-sectional structure of the present invention as a whole;

[0026] Figure 3 Schematic diagram of the three-dimensional structure of the elastic strip, winding tube and annular plate of the present invention;

[0027] Figure 4 Schematic diagram of the three-dimensional cross-sectional structure of the annular plate of the present invention;

[0028] Figure 5 Schematic diagram of the three-dimensional structure of the master gear and the slave gear of the present invention;

[0029] Figure 6 It is a schematic diagram of the three-dimensional structure of the vertical rod, extension plate and inner block of the present invention;

[0030] Figure 7 Schematic diagram of the three-dimensional cross-sectional structure of the cleaning plate of the present invention;

[0031] Figure 8 It is a schematic diagram of the three-dimensional structure of the L-shaped mounting block and the extrusion strip of the present invention.

[0032] In the figure: 1. kettle body; 2. liquid level gauge; 3. motor; 4. catalyst inlet container; 5. liquid dispenser; 6. annular cover; 7. annular plate; 8. cleaning ring; 9. upper liquid pipe; 10. lower liquid pipe; 11. L-shaped mounting block; 12. telescopic tube; 13. winding tube; 14. elastic strip; 15. multi-stage electric push rod; 16. main gear; 17. slave gear; 18. mounting plate; 19. drainage rod; 20. extension plate; 21. fixed block; 22. slot; 23. follower plate; 24. inner block; 25. movable groove; 26. annular groove; 27. vertical rod; 28. slot; 29. clamping block; 30. movable block; 31. spring; 32. cleaning pipe; 33. nozzle; 34. extrusion strip. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0034] See also Figure 1 - Figure 8 A method and device for preparing p-nitrobenzyl alcohol, comprising a kettle body 1, a liquid level gauge 2 connected to the kettle body 1, an annular cover 6 fixedly connected to the inner wall of the kettle top, an elastic strip 14 fixedly connected to the annular cover 6, an annular plate 7 fixedly connected to the bottom of the elastic strip 14, a winding pipe 13 fixedly connected to the top of the annular plate 7, a catalyst introduction container 4 fixedly mounted on the top of the kettle body 1, an annular groove 26 opened in the annular plate 7, and a catalyst introduction container 4 fixedly mounted on the top of the annular plate 7. 6 is connected to the slot 22, the inner wall of the annular plate 7 is fixedly connected to the follower plate 23, the inner wall of the annular cover 6 is fixedly connected to the multi-stage electric push rod 15, the output end of the multi-stage electric push rod 15 is connected to the follower plate 23, the bottom of the annular plate 7 is connected to the drainage piece, the outside of the kettle top of the kettle body 1 is connected to the liquid collector 5, the liquid collector 5 passes through the inner wall of one end of the kettle body 1 and is connected to the sampling structure, the inner wall of the kettle body 1 is connected to the cleaning structure, and the outer wall of the annular plate 7 is connected to three groups of clamping parts for connecting the sampling structure and the cleaning structure.

[0035] A method and apparatus for preparing p-nitrobenzyl alcohol according to the present invention, when the catalyst needs to be introduced, only the liquid level in the kettle body 1 needs to be detected by the liquid level gauge 2. Then, based on the feedback from the liquid level gauge 2, the multi-stage electric push rod 15 can be controlled by the control unit of the reactor itself, such as a programmable logic controller. The multi-stage electric push rod 15 is started after receiving the instruction, and the output end of the multi-stage electric push rod 15 is actuated to drive the follower plate 23 to move, thereby driving the annular plate 7 to move, so that the annular plate 7 is close to the liquid surface but does not contact the liquid surface. During the descent of the annular plate 7, the elastic strip 14 is unfolded and the winding tube 13 is unfolded. The winding tube 13 is connected to the annular groove 26 in the annular plate 7. The top of the winding tube 13 is connected to the catalyst introduction container 4 outside the kettle top. After the catalyst is introduced into the container 4, it enters the annular groove 26 in the annular plate 7 through the winding tube 13 and finally falls into the liquid surface through the slot 22. This arrangement allows the liquefier to drip out close to the liquid surface when it is dripped in.

[0036] Through the coordinated arrangement of the annular cover 6, the winding tube 13, the elastic strip 14, the annular plate 7 and the multi-stage electric push rod 15, it is possible to ensure that the catalyst is accurately adjusted in the addition process according to the real-time monitoring of the liquid level meter 2. The multi-stage electric push rod 15 changes flexibly according to the position of the liquid surface, so that the catalyst can be added at a suitable distance at different liquid level heights, effectively preventing the problem of excessive local reaction caused by direct dripping at a high position. In addition, the multiple slots 22 specially designed at the bottom of the annular plate 7 further ensure that the catalyst is evenly distributed when dripping into the liquid surface, thereby optimizing the entire chemical reaction process.

[0037] It is worth noting that in the above structure, the liquid level meter 2 and the multi-stage electric push rod 15 are both existing mature technologies. Operating the multi-stage electric push rod 15 through a control unit such as a programmable logic controller is already an existing mature technology, so it will not be described in detail here.

[0038] As a preferred technical solution of the present invention, the drainage member includes multiple drainage rods 19, the drainage rods 19 are located below the slots 22, the drainage rods 19 are inclined, and the top of the drainage rods 19 is fixedly connected to a mounting plate 18, which is fixed to the annular plate 7 by bolts.

[0039] Specifically, when the catalyst drips out through the slot 22, since the drainage rod 19 is tilted and arranged below the slot 22, when the catalyst drips, the drainage rod 19 cleverly guides the catalyst to flow smoothly into the liquid, ensuring that it is gently integrated into the reaction medium. This design not only makes the catalyst addition process smoother and gentler, but also greatly optimizes the contact mode between the catalyst and the reactants, promotes a more uniform and more effective chemical reaction, and significantly improves the entire catalytic process, further ensuring the reaction efficiency and product quality.

[0040] At the same time, the drainage rod 19 is fixed to the annular plate 7 through the mounting plate 18 and bolts, ensuring that the drainage rod 19 is easy to replace.

[0041] As a preferred technical solution of the present invention, the sampling structure includes an upper liquid collection tube 9, which is sealed and connected to the bottom of the liquid collector 5 through the top of the kettle. The bottom of the upper liquid collection tube 9 is fixedly connected to a telescopic tube 12, and the bottom of the telescopic tube 12 is fixedly connected to a lower liquid collection tube 10.

[0042] Specifically, when it is necessary to sample the reacted medium in the kettle body 1, the annular plate 7 can be connected to the liquid sampling tube 10 through the clamping part. Therefore, when the multi-stage electric push rod 15 is pushed, the annular plate 7 will drive the liquid sampling tube 10 to also descend, so that the liquid sampling tube 10 enters the liquid surface for sampling. After the liquid sampling tube 10 is opened, it will drive the telescopic tube 12 to extend, thereby making the liquid sampling tube 10 extend into the liquid surface. This design ensures that the sampling tube will not be immersed in the reaction medium in the non-sampling state, thereby avoiding unnecessary pollution and the influence of chemical reactions on the sampling equipment, and also ensuring the accuracy of each sampling.

[0043] It is worth noting that the telescopic tube 12 should be a pipe with corrosion resistance, high temperature resistance and other conditions to ensure its service life.

[0044] The liquid extractor 5 in the above structure is a mature technology, so it will not be described in detail here.

[0045] As an optimal technical solution of the present invention, the cleaning structure includes a cleaning ring 8, which is movably connected to the inner wall of the kettle body 1, a cleaning pipe 32 is fixedly connected to the top of the cleaning ring 8, and a plurality of nozzles 33 are fixedly connected to the outer wall of the cleaning ring 8. The cleaning pipe 32 passes through one end outside the top of the kettle and is connected to a high-pressure water pump.

[0046] Specifically, after the reaction of the compound in the kettle body 1 is completed, the kettle body 1 needs to be cleaned. At this time, the clamping piece can be separated from the sampling structure, and then the other two clamping pieces can be clamped with the cleaning structure. At this time, when the multi-stage electric push rod 15 descends, it will drive the cleaning ring 8 to descend together. At this time, the outer end of the cleaning pipe 32 on the top of the cleaning ring 8 is connected to a high-pressure water pump, so that water passes through the cleaning pipe 32 and the cleaning ring 8, and is sprayed through the nozzle 33 to spray the inner wall of the kettle body 1. The multi-stage electric push rod 15 can move up and down continuously, so that the cleaning effect of the inner wall of the kettle body 1 is good;

[0047] At this time, high-pressure water can also be injected into the winding pipe 13 to flush the winding pipe 13 and the inside of the annular plate 7 to ensure the next use.

[0048] By coordinating the cleaning ring 8 and the nozzle 33, the inner wall of the kettle body 1 can be flushed by a high-pressure water source, so that the cleaning effect of the inner wall of the kettle body 1 is good. By pushing the multi-stage electric push rod 15, the cleaning ring 8 can move up and down the inner wall of the kettle body 1, so that the cleaning effect is better.

[0049] As a preferred technical solution of the present invention, two of the clips are connected to the cleaning structure, and the other clip is connected to the sampling structure. The three clips all include an inner block 24 fixedly connected to the inner wall of the annular plate 7, a movable groove 25 is provided in the inner block 24, a movable block 30 is slidably connected in the movable groove 25, the bottom surface of the movable block 30 is fixedly connected to the extension plate 20, and the end of the extension plate 20 is fixedly connected to the clamping block 29. The inner walls of the liquid taking tube 10 and the cleaning ring 8 are fixedly connected with the fixed block 21, and a clamping groove 28 corresponding to the clamping block 29 is provided in the fixed block 21. Two clamping blocks 29 are fixedly connected to the inner wall of the cleaning ring 8, and another clamping block 29 is fixedly connected to the outer wall of the liquid taking tube 10. The outer wall of the annular cover 6 is connected with a transmission assembly for driving the clamping block 29 to engage.

[0050] Specifically, in order to enable the liquid extraction tube 10 to move up and down following the multi-stage electric push rod 15 and the annular plate 7, the transmission assembly can be driven to squeeze the extension plate 20, driving the block 29 at the front end of the extension plate 20 to engage with the slot 28 in the fixed block 21. When the extension plate 20 is rotated and engaged in the fixed block 21, the moving block 30 at the tail of the extension plate 20 moves in the moving slot 25 in the inner block 24. When the extension plate 20 is squeezed and engaged, the extension plate 20 rotates about the axis of the annular plate 7. This arrangement allows the liquid extraction tube 10 to be connected to the annular plate 7 through the block 29. When the block 29 is engaged, the annular plate 7 descends, which will simultaneously drive the liquid extraction tube 10 to move downward.

[0051] When entering the cleaning stage, the clamping parts on the outside of the liquid extraction tube 10 can be separated from it first, and then the transmission assembly can be driven to drive the other two extension plates 20 to rotate, so that the clamping block 29 is engaged with the clamping groove 28 in the fixed block 21, so that the cleaning ring 8 is connected to the annular plate 7. In this way, the lowering of the annular plate 7 can simultaneously drive the cleaning ring 8 to descend.

[0052] As a preferred technical solution of the present invention, the transmission assembly includes a main gear 16 and a slave gear 17. The motor 3 is fixedly connected to the outer side of the top of the kettle body 1. The output end of the motor 3 passes through the top of the kettle and is fixedly connected to the main gear 16. The outer wall of the annular cover 6 is rotatably connected to the slave gear 17. The slave gear 17 is meshed with the main gear 16. The bottom surface of the slave gear 17 is fixedly connected to vertical rods 27 corresponding to the three extension plates 20 respectively, and the outer wall of the vertical rod 27 is against the outer wall of the extension plate 20.

[0053] Specifically, when the liquid extraction tube 10 needs to be connected to the annular plate 7, the motor 3 can be started, and the motor 3 rotates, driving the main gear 16 to engage with the slave gear 17. The slave gear 17 rotates on the outside of the annular cover 6. At the same time, the three vertical rods 27 on the bottom surface of the slave gear 17 rotate simultaneously around the axis of the annular plate 7. One of the vertical rods 27 will squeeze the extension plate 20 located on the outside of the liquid extraction tube 10, driving the clamping block 29 to engage with the clamping groove 28.

[0054] At this time, the other two vertical rods 27 will move away from the extension plate 20 close to them, and will not be squeezed by the other two extension plates 20;

[0055] When the cleaning ring 8 needs to be connected, the motor 3 can be reversed to rotate the slave gear 17, driving the other two vertical rods 27 to rotate, and separating the vertical rod 27 located on one side of the liquid extraction pipe 10 from the corresponding extension plate 20. Then, the rotation of the two vertical rods 27 will squeeze the other two extension plates 20, causing the clamping block 29 to be clamped into the clamping groove 28 in the fixed block 21 on the inner wall of the cleaning ring 8;

[0056] Through the above structure, the cleaning structure and the sampling structure can be engaged with and disengaged from the annular plate 7 under the drive of the motor 3, thereby realizing their respective functions.

[0057] The motor 3 in the above structure is an existing mature technology, so it will not be described in detail here.

[0058] As a preferred technical solution of the present invention, the outer wall of one end of the moving block 30 located in the moving groove 25 is fixedly connected to a spring 31 , and the other end of the spring 31 abuts against the inner wall of the moving groove 25 .

[0059] Specifically, when the extension plate 20 is squeezed, the moving block 30 at the end will slide in the moving groove 25 and squeeze the spring 31 at the same time. When the vertical rod 27 loses its squeeze, the extension plate 20 loses its restriction. At this time, the spring 31 will push the moving block 30 back to its original position, so that the blocking block 29 at the end of the extension plate 20 can automatically disengage from the blocking groove 28.

[0060] As a preferred technical solution of the present invention, the inner wall of the kettle body 1 is fixedly connected with multiple L-shaped mounting blocks 11, the outer wall of the cleaning ring 8 is slidingly connected to the inner wall of the L-shaped mounting block 11, and the inner wall of the vertical plate of the L-shaped mounting block 11 is fixedly connected with an extrusion strip 34.

[0061] Specifically, in order to ensure that the cleaning ring 8 is stably connected to the inner wall of the kettle body 1, the cleaning ring 8 is confined in the L-shaped mounting block 11 by relying on the friction and limiting force with the extrusion strip 34. When the cleaning ring 8 is subjected to the hard downward pressure of the annular plate 7 and the multi-stage electric push rod 15, the cleaning ring 8 will be detached from the L-shaped mounting block 11.

[0062] As a preferred technical solution of the present invention, the annular groove 26 is arranged in an inverted trapezoidal shape, which can make the catalyst flow out of the slot hole 22 more smoothly.

[0063] A method for preparing p-nitrobenzyl alcohol, using the p-nitrobenzyl alcohol preparation device as described above, specifically comprises the following steps:

[0064] a. Add para-nitrotoluene and water into a reactor, stir and heat to 40~55°C, then add bromine dropwise, and add the initiator dropwise in batches under insulation conditions. After the initiator is added, continue the insulation reaction;

[0065] b. Sodium sulfite was added to the product obtained by the bromination reaction to whiten it. After stirring, water was added and the temperature was raised to 100 ° C for reflux hydrolysis. The hydrolysis time was 4 to 10 hours. After the hydrolysis was completed, the temperature was lowered to 70 ° C and sodium carbonate was added to adjust the pH value.

[0066] c. Add a solvent to the product obtained by the whitening and hydrolysis reactions, let it stand and separate into layers, and then obtain an oil solution layer and an aqueous solution layer. The oil solution layer is concentrated, cooled, crystallized, and filtered to obtain crude p-nitrobenzyl alcohol.

[0067] Specifically, by using the above-mentioned p-nitrobenzyl alcohol preparation device to prepare p-nitrobenzyl alcohol, it is possible to ensure that the catalyst drop height is accurately adjusted during the addition process, so that the catalyst can be added at an appropriate distance at different liquid level heights, effectively preventing the problem of excessive local reaction caused by direct dropwise addition at a high position.

[0068] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A p-nitrobenzyl alcohol preparation device, comprising a kettle (1), characterized in that: The kettle body (1) is connected to a liquid level gauge (2), the inner wall of the kettle top of the kettle body (1) is fixedly connected to an annular cover (6), an elastic strip (14) is fixedly connected to the inner wall of the annular cover (6), an annular plate (7) is fixedly connected to the bottom of the elastic strip (14), the top of the annular plate (7) is fixedly connected to a winding pipe (13), the top of the winding pipe (13) is connected to a catalyst introduction container (4) fixedly mounted on the top of the kettle body (1), an annular groove (26) is provided in the annular plate (7), a slot (22) communicating with the annular groove (26) is provided at the bottom of the annular plate (7), a follower plate (23) is fixedly connected to the inner wall of the annular plate (7), and a multi-stage electric Push rod (15), the output end of the multi-stage electric push rod (15) is connected to the follower plate (23), the bottom of the annular plate (7) is connected to the drainage piece, the outer side of the kettle top of the kettle body (1) is connected to a liquid collector (5), the liquid collector (5) is arranged through the inner wall of one end of the kettle body (1) and is connected to a sampling structure, the sampling structure includes a liquid collection upper tube (9), the bottom of the liquid collection upper tube (9) is fixedly connected to a telescopic tube (12), the bottom of the telescopic tube (12) is fixedly connected to a liquid collection lower tube (10), the inner wall of the kettle body (1) is connected to a cleaning structure, the cleaning structure includes a cleaning ring (8), the cleaning ring (8) is movably connected to the inner wall of the kettle body (1), and the outer wall of the annular plate (7) is connected to three groups for connecting the sampling structure and the cleaning structure. The clamping parts are connected to the cleaning structure, and the other clamping part is connected to the sampling structure. The three clamping parts all include an inner block (24) fixedly connected to the inner wall of the annular plate (7). A moving groove (25) is provided in the inner block (24). A moving block (30) is slidably connected in the moving groove (25). The bottom surface of the moving block (30) is fixedly connected to the extension plate (20). The end of the extension plate (20) is fixedly connected to the clamping block (29). The inner walls of the liquid taking tube (10) and the cleaning ring (8) are fixedly connected to the fixed block (21). A clamping groove (28) corresponding to the clamping block (29) is provided in the fixed block (21). The two clamping blocks (29) are fixedly connected to the cleaning structure. The inner wall of the washing ring (8), another clamping block (29) is fixedly connected to the outer wall of the liquid extraction pipe (10), the outer wall of the annular cover (6) is connected with a transmission assembly for driving the clamping block (29), and the transmission assembly includes a main gear (16) and a slave gear (17), the outer wall of the annular cover (6) is rotatably connected to the slave gear (17), and the bottom surface of the slave gear (17) is fixedly connected with a vertical rod (27) corresponding to the three extension plates (20), and the outer wall of the vertical rod (27) is against the outer wall of the extension plate (20), and the outer wall of the moving block (30) is fixedly connected to a spring (31) at one end of the outer wall of the moving groove (25), and the other end of the spring (31) is against the inner wall of the moving groove (25).

2. A p-nitrobenzyl alcohol preparation device according to claim 1, characterized in that, The drainage member comprises a plurality of drainage rods (19), the drainage rods (19) being located below the slots (22), the drainage rods (19) being arranged at an angle, and the tops of the drainage rods (19) being fixedly connected to a mounting plate (18), which is fixedly mounted to the annular plate (7) by bolts.

3. A p-nitrobenzyl alcohol preparation device according to claim 1, characterized in that, The liquid collection upper tube (9) is sealedly connected to the bottom of the liquid collection device (5) through the top of the kettle.

4. A p-nitrobenzyl alcohol preparation device according to claim 1, characterized in that, A cleaning pipe (32) is fixedly connected to the top of the cleaning ring (8), and a plurality of nozzles (33) are fixedly connected to the outer wall of the cleaning ring (8). One end of the cleaning pipe (32) passes through the outside of the kettle top and is connected to a high-pressure water pump.

5. A p-nitrobenzyl alcohol preparation device according to claim 1, characterized in that, The top outer side of the kettle body (1) is fixedly connected to a motor (3), the output end of the motor (3) passes through the kettle top and is fixedly connected to the main gear (16), and the slave gear (17) is meshed and connected to the main gear (16).

6. A p-nitrobenzyl alcohol preparation device according to claim 1, characterized in that, The inner wall of the kettle body (1) is fixedly connected to a plurality of L-shaped mounting blocks (11), the outer wall of the cleaning ring (8) is slidably connected to the inner wall of the L-shaped mounting block (11), and the inner wall of the vertical plate of the L-shaped mounting block (11) is fixedly connected to an extrusion strip (34).

7. A p-nitrobenzyl alcohol preparation device according to claim 1, characterized in that, The annular groove (26) is arranged in an inverted trapezoidal shape.

8. A method for preparing p-nitrobenzyl alcohol, characterized in that: The production process using the p-nitrobenzyl alcohol preparation device according to any one of claims 1 to 7 comprises the following steps: a. Add para-nitrotoluene and water into a reactor, stir and heat to 40~55°C, then add bromine dropwise, and add the initiator dropwise in batches under insulation conditions. After the initiator is added, continue the insulation reaction; b. Sodium sulfite was added to the product obtained by the bromination reaction to whiten it. After stirring, water was added and the temperature was raised to 100 ° C for reflux hydrolysis. The hydrolysis time was 4 to 10 hours. After the hydrolysis was completed, the temperature was lowered to 70 ° C and sodium carbonate was added to adjust the pH value. c. Add a solvent to the product obtained by the whitening and hydrolysis reactions, let it stand and separate into layers, and then obtain an oil solution layer and an aqueous solution layer. The oil solution layer is concentrated, cooled, crystallized, and filtered to obtain crude p-nitrobenzyl alcohol.

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