Device for efficiently and continuously synthesizing 2, 5-dihydrofuran

Abstract

The utility model belongs to the technical field of devices for synthesizing 2, 5-dihydrofuran, and discloses a device for efficiently and continuously synthesizing 2, 5-dihydrofuran, which comprises a reaction kettle, the top end of the reaction kettle is connected with a first material guide pipeline, the first material guide pipeline is provided with a reflux tower, the reflux tower is connected with a second material guide pipeline, and the second material guide pipeline is provided with a second material outlet. A heat exchanger is installed on the second material guiding pipeline, a third material guiding pipeline is connected to the bottom end of the heat exchanger, a backflow tank is installed on the third material guiding pipeline, a fourth material guiding pipeline and a fifth material guiding pipeline are connected to the lower portion of the backflow tank, the fourth material guiding pipeline is communicated with a backflow tower, and the fifth material guiding pipeline is communicated with the backflow tower. According to the utility model, a section of reflux tower is additionally arranged on the gas phase discharge pipeline of the reaction kettle, and the unreacted raw material BED in a crude product flows back to the reaction kettle by utilizing the advantage that the boiling point difference of materials is large, so that the distillation process can be reduced, the raw material utilization rate and the product yield are improved, the raw material conversion rate is 100%, and the product yield is improved.

Description

Technical Field

[0001] This invention belongs to the technical field of apparatus for synthesizing 2,5-dihydrofuran, and specifically relates to an apparatus for the efficient continuous synthesis of 2,5-dihydrofuran. Background Technology

[0002] 2,5-Dihydrofuran is a key raw material for the preparation of the pharmaceutical intermediate 2,3-dihydrofuran. The two are isomers. 2,3-Dihydrofuran is widely used in electronic chemicals and liquid crystal display liquids, and is also used in the production of anticancer drugs such as etodoxacin and tegafur. 2,5-Dihydrofuran is an important raw material for the synthesis of 3-aminomethyltetrahydrofuran, which is the main raw material for the synthesis of fipronil. Fipronil is a low-toxicity neonicotinoid insecticide with broad market prospects.

[0003] The current route for synthesizing this product involves dehydrating and cyclizing 1,4-butenediol (BED) under acidic catalyst conditions to obtain 2,5-dihydrofuran. The current process is crude product synthesis - distillation - dehydration - rectification - product.

[0004] The existing authorized patent CN201910652399.4, "A method for preparing 2,5-dihydrofuran by membrane separation coupled cyclization", uses acidic morpholine ionic liquid as a catalyst to achieve a clean production process that combines the synthesis of 2,5-dihydrofuran with membrane separation and post-treatment dehydration technology with high selectivity. It has the advantages of low energy consumption, low emissions and simple maintenance of reaction equipment. However, this patent does not describe the apparatus and features for synthesizing crude products.

[0005] CN201711350185.9 "A method for preparing 2,5-dihydrofuran" This invention improves the reaction yield and product purity by adding a dehydrating agent to remove the generated water at low temperature. At the same time, this invention uses a molecular sieve catalyst to catalyze the reaction, which greatly reduces the reaction temperature and also enables the catalyst to be recovered. However, this patent does not describe the apparatus and features for synthesizing the crude product.

[0006] Using a reactor equipped only with a stirring device, after the synthesis of the crude product is completed, due to the high reaction temperature, the crude product contains a high content of unreacted raw material 1,4-butenediol (BED) (boiling point 234℃). In order to reduce the burden of subsequent product distillation, a distillation step needs to be added. This process has high energy consumption, large product loss, and increased product cost. In addition, when adding materials, solid raw materials are easy to stick to the wall of the feed pipe, which not only affects the utilization rate of raw materials, but also makes the pipe difficult to clean. Utility Model Content

[0007] The purpose of this invention is to provide an efficient continuous synthesis apparatus for 2,5-dihydrofuran, which solves the problems mentioned in the background art. Due to the high reaction temperature, the crude product contains a high content of unreacted raw material 1,4-butenediol (BED) (boiling point 234℃). To reduce the burden of subsequent product distillation, an additional distillation step is required, which consumes a lot of energy, results in significant product loss, and increases product costs. Furthermore, during the feeding process, solid raw materials tend to adhere to the walls of the feed pipe, which not only affects the utilization rate of the raw materials but also makes the pipe difficult to clean.

[0008] To achieve the above objectives, this utility model provides the following technical solution: an apparatus for the efficient continuous synthesis of 2,5-dihydrofuran, comprising: a reactor, a first feed pipe connected to the top of the reactor, a reflux tower installed on the first feed pipe, a second feed pipe connected to the reflux tower, a heat exchanger installed on the second feed pipe, a third feed pipe connected to the bottom of the heat exchanger, a reflux tank installed on the third feed pipe, and a fourth and fifth feed pipes connected below the reflux tank, wherein the fourth feed pipe is connected to the reflux tower.

[0009] Preferably, the reactor is connected to a feed pipe, a mounting plate is connected to the side wall of the feed pipe, a vertical electric telescopic rod is connected to the mounting plate, a connecting plate is installed at the output end of the electric telescopic rod, and a feeding assembly is installed on the connecting plate.

[0010] Preferably, the feeding assembly includes a motor, a first rotating shaft, and a feeding scoop. The motor is horizontally mounted on the connecting plate, the first rotating shaft is connected to the output end of the motor, the feeding scoop is mounted on the outer wall of the first rotating shaft, and the feeding assembly can move within the feeding pipe.

[0011] Preferably, a cover is installed on the feed pipe, the inner wall of the cover is provided with a threaded groove, and the outer wall of the feed pipe is provided with an external thread, the threaded groove and the external thread being compatible.

[0012] Preferably, the bottom end of the reactor is connected to a discharge pipe, and the reactor is equipped with a stirring assembly.

[0013] Preferably, the stirring assembly includes a motor, a second rotating shaft, and blades. The motor is mounted on the top of the reactor, the second rotating shaft is connected to the output end of the motor, and the blades are mounted on the outer wall of the second rotating shaft.

[0014] Compared with the prior art, the beneficial effects of this utility model are:

[0015] (1) This utility model improves the utilization rate of raw materials and the product yield by setting up a reflux tower, heat exchanger and reflux tank. When in use, the crude product enters the reflux tower from the top of the reactor. The unreacted BED is returned to the reactor. 2,5-dihydrofuran and water vapor enter the heat exchanger and are condensed before entering the reflux tank. Part of the crude product in the reflux tank is discharged and part of it is returned to the reflux tower. This device adds a section of reflux tower to the gas phase discharge pipeline of the reactor. Taking advantage of the large difference in boiling points of the materials, the unreacted raw material BED in the crude product is returned to the reactor. This can reduce the distillation process, improve the utilization rate of raw materials and the product yield, make the raw material conversion rate 100% and improve the product yield.

[0016] (2) This utility model adds solid raw materials by setting up an electric telescopic rod, a motor and a feeding spoon. When in use, the raw materials are first placed in the feeding spoon. After the feed pipe is opened, the electric telescopic rod drives the feeding component to extend into the reactor. Then the motor drives the feeding spoon to pour the raw materials into the reactor, thereby avoiding contact between the raw materials and the inner wall of the feed pipe, preventing the raw materials from sticking to the wall of the feed pipe, improving the utilization rate of the raw materials, and reducing the difficulty and frequency of cleaning the feed pipe. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of this utility model;

[0018] Figure 2 This is a schematic diagram of the structure of the reaction vessel of this utility model;

[0019] Figure 3 This is a schematic diagram of the reflux tower of this utility model;

[0020] Figure 4 for Figure 2 Enlarged view of part A in the image;

[0021] In the diagram: 1. Reactor; 2. Reflux tower; 3. Heat exchanger; 4. Reflux tank; 5. First feed pipe; 6. Second feed pipe; 7. Third feed pipe; 8. Fourth feed pipe; 9. Fifth feed pipe; 10. Feed pipe; 11. Mounting plate; 12. Electric telescopic rod; 13. Connecting plate; 14. Motor; 15. First rotating shaft; 16. Feeding spoon; 17. Cover; 18. Threaded groove; 19. External thread; 20. Motor; 21. Second rotating shaft; 22. Blade; 23. Discharge pipe. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figures 1-3 As shown, this utility model provides the following technical solution: an apparatus for efficient continuous synthesis of 2,5-dihydrofuran, comprising: a reactor 1, a first feed pipe 5 connected to the top of the reactor 1, a reflux tower 2 installed on the first feed pipe 5, a second feed pipe 6 connected to the reflux tower 2, a heat exchanger 3 installed on the second feed pipe 6, a third feed pipe 7 connected to the bottom of the heat exchanger 3, a reflux tank 4 installed on the third feed pipe 7, and a fourth feed pipe 8 and a fifth feed pipe 9 connected below the reflux tank 4, wherein the fourth feed pipe 8 is connected to the reflux tower 2.

[0024] Through the above technical solution:

[0025] In operation, a catalyst is first added to reactor 1, followed by continuous addition of 97% BED. Once the reaction temperature is reached, the crude product enters the reflux tower 2 from the top of reactor 1 via the first feed pipe 5. Unreacted BED is then returned to reactor 1. 2,5-Dihydrofuran and water vapor enter the heat exchanger 3 via the second feed pipe 6. After condensation, they enter the reflux tank 4 via the third feed pipe 7. Part of the crude product in the reflux tank 4 is discharged via the fifth feed pipe 9, while the rest is returned to the reflux tower 2 via the fourth feed pipe 8. This device adds a reflux tower 2 section to the gas phase outlet pipeline of reactor 1, utilizing the significant difference in boiling points of the materials to reflux the unreacted raw material BED from the crude product back to reactor 1. This reduces distillation steps, improves raw material utilization and product yield, achieving 100% raw material conversion, increasing product yield, effectively reducing product costs, and lowering energy consumption in production.

[0026] Please see Figure 1 , Figure 2 and Figure 4 As shown, a feed pipe 10 is connected to the reactor 1, an mounting plate 11 is connected to the side wall of the feed pipe 10, an upright electric telescopic rod 12 is connected to the mounting plate 11, a connecting plate 13 is installed at the output end of the electric telescopic rod 12, and a feeding assembly is installed on the connecting plate 13.

[0027] Furthermore, the feeding assembly includes a motor 14, a first rotating shaft 15, and a feeding spoon 16. The motor 14 is horizontally mounted on the connecting plate 13, the first rotating shaft 15 is connected to the output end of the motor 14, the feeding spoon 16 is mounted on the outer wall of the first rotating shaft 15, and the feeding assembly can move within the feeding pipe 10.

[0028] Furthermore, a cover 17 is installed on the feed pipe 10. The inner wall of the cover 17 is provided with a threaded groove 18, and the outer wall of the feed pipe 10 is provided with an external thread 19. The threaded groove 18 and the external thread 19 are compatible.

[0029] Through the above technical solution:

[0030] When adding solid raw materials to the reactor 1, first place the raw materials in the feeding scoop 16, then screw on the cover 17 to separate the external thread 19 and the threaded groove 18, opening the feed pipe 10. Next, start the electric telescopic rod 12, which drives the feeding assembly to extend from the feed pipe 10 into the reactor 1. After entering, start the motor 14, which drives the feeding scoop 16 to rotate via the first rotating shaft 15. The rotating feeding scoop 16 pours the raw materials into the reactor 1, thus preventing the raw materials from contacting the inner wall of the feed pipe 10 and avoiding the raw materials from sticking to the wall inside the feed pipe 10. This ensures that all the raw materials enter the reactor 1, thereby improving the utilization rate of the raw materials and reducing the difficulty and frequency of cleaning the feed pipe 10, reducing maintenance workload and costs.

[0031] For further details, please refer to Figures 1-2 As shown, the bottom end of the reactor 1 is connected to the discharge pipe 23, and the reactor 1 is equipped with a stirring assembly.

[0032] Furthermore, the stirring assembly includes a motor 20, a second rotating shaft 21, and blades 22. The motor 20 is installed at the top of the reactor 1, the second rotating shaft 21 is connected to the output end of the motor 20, and the blades 22 are installed on the outer wall of the second rotating shaft 21.

[0033] Specifically, the discharge pipe 23 can discharge the waste material in the reactor 1. During the synthesis, the motor 20 is started. The motor 20 drives the blades 22 to rotate through the second rotating shaft 21. The rotating blades 22 stir the reactants. Stirring can accelerate the mixing between reactants, ensure that the reactants are in full contact, thereby speeding up the chemical reaction rate. Stirring also helps to evenly disperse the heat in the reactor, prevent local overheating or overcooling, and thus maintain the constant temperature conditions required for the reaction.

[0034] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. An apparatus for the efficient continuous synthesis of 2,5-dihydrofuran, characterized in that, Include: The reaction kettle (1), the top end of the reaction kettle (1) is connected with the first material guide pipe (5), the first material guide pipe (5) is installed with reflux tower (2), the reflux tower (2) is connected with the second material guide pipe (6), the second material guide pipe (6) is installed with heat exchanger (3), the bottom end of the heat exchanger (3) is connected with the third material guide pipe (7), the third material guide pipe (7) is installed with reflux tank (4), the lower side of the reflux tank (4) is connected with the fourth material guide pipe (8) and the fifth material guide pipe (9), and the fourth material guide pipe (8) is communicated with the reflux tower (2).

2. The apparatus for efficient continuous synthesis of 2,5-dihydrofuran according to claim 1, characterized in that: The reaction kettle (1) is connected with the feeding pipe (10), the side wall of the feeding pipe (10) is connected with the mounting plate (11), the mounting plate (11) is connected with the vertical electric telescopic rod (12), the output end of the electric telescopic rod (12) is installed with the connecting plate (13), and the connecting plate (13) is installed with the feeding assembly.

3. The apparatus for efficient continuous synthesis of 2,5-dihydrofuran according to claim 2, characterized in that: The feeding assembly includes a motor (14), a first rotating shaft (15) and a feeding spoon (16), the motor (14) is transversely installed on the connecting plate (13), the first rotating shaft (15) is connected to the output end of the motor (14), the feeding spoon (16) is installed on the outer wall of the first rotating shaft (15), and the feeding assembly can move in the feeding pipe (10).

4. The apparatus for efficient continuous synthesis of 2,5-dihydrofuran according to claim 2, characterized in that: The feeding pipe (10) is installed with a cover (17), a threaded groove (18) is formed in the inner wall of the cover (17), and an external thread (19) is formed in the outer wall of the feeding pipe (10). The threaded groove (18) and the external thread (19) are matched.

5. The apparatus for efficient continuous synthesis of 2,5-dihydrofuran according to claim 1, characterized in that: The bottom end of the reaction kettle (1) is connected with the discharging pipe (23), and the reaction kettle (1) is provided with a stirring assembly.

6. The apparatus for efficient continuous synthesis of 2,5-dihydrofuran according to claim 5, characterized in that: The stirring assembly includes a motor (20), a second rotating shaft (21) and a blade (22), the motor (20) is installed at the top end of the reaction kettle (1), the second rotating shaft (21) is connected to the output end of the motor (20), and the blade (22) is installed on the outer wall of the second rotating shaft (21).

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