A reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid

Abstract

The utility model discloses a reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid, and relates to the technical field related to organic chemistry. The utility model includes an evaporation box, a transfer box, a driving motor, a closing cover and a reactor, one side of the evaporation box is fixedly connected with an output pipe, and the output pipe is fixedly connected with a transfer box at one end away from the evaporation box, and the transfer box is fixed with a driving motor at the lower part of one side of the evaporation box, and the bottom end of the transfer box is fixedly connected with an electric control valve 2, and the bottom end of the electric control valve 2 is fixedly connected with a closing cover, and the bottom end of the closing cover is provided with a reactor and the top of the reactor and the bottom end of the closing cover are mutually abutted. The utility model solves the problem that after pyrazine-2,3-dicarboxylic acid is directly extracted, the yield is not high enough, and the pyrazine-2,3-dicarboxylic acid crystals repeatedly extracted after recrystallization are easily adhered to the reactor, causing the problem that the crystal separation is not convenient enough.

Description

Technical Field

[0001] The utility model belongs to the technical field related to organic chemistry, and particularly relates to a reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid. Background Art

[0002] The synthesis of pyrazine-2,3-dicarboxylic acid is obtained by oxidation with potassium permanganate using benzopyrazine as raw material. First, water and benzopyrazine are put into the reaction pot, and potassium permanganate is evenly added under stirring. The temperature is kept at 68-70℃ for 2h, the end point is measured, and it is left overnight. The upper clear liquid is absorbed, and the lower layer is stirred with water, heated to 80℃ and filtered. The upper clear liquid and the filtrate are concentrated by a thin film evaporator, and then taken out and neutralized with hydrochloric acid to pH=2, and pyrazine dicarboxylic acid monopotassium salt is precipitated, cooled, and filtered at 25℃. The filter cake is added to hydrochloric acid, stirred and heated to completely dissolved, cooled and crystallized at below 15℃, filtered, washed with a little ethanol, and dried to obtain a crystalline product. The yield is 70% based on benzopyrazine, but it still has the following disadvantages in actual use:

[0003] 1. After the filter cake is dissolved by adding hydrochloric acid, the crystal product can be obtained by recrystallization. However, there is still finished product in the hydrochloric acid solution. Direct wastewater treatment will cause waste of finished product and the recovery rate of crystal product is not high enough.

[0004] 2. When repeatedly extracting pyrazine-2,3-dicarboxylic acid, pyrazine-2,3-dicarboxylic acid needs to be treated and then crystallized. However, after crystallization, the crystals need to be filtered to separate the solvent and the crystals. However, the crystals are easily adhered to the inner wall of the recrystallization reactor, resulting in inconvenient crystal separation. Utility Model Content

[0005] The utility model aims to provide a reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid. By arranging an evaporation box, a transfer box, a driving motor, a closing cover and a reaction kettle, the utility model solves the problems that the yield of pyrazine-2,3-dicarboxylic acid is not high enough after direct extraction, and the pyrazine-2,3-dicarboxylic acid crystals repeatedly extracted after recrystallization are easy to adhere to the reaction kettle, resulting in inconvenient crystal separation.

[0006] In order to solve the above technical problems, the utility model is realized by the following technical solutions:

[0007] The utility model discloses a reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid, comprising an evaporation box, a transfer box, a driving motor, a closing cover and a reactor. One side of the evaporation box is fixedly connected with an output pipe, one end of the output pipe away from the evaporation box is fixedly connected with the transfer box, a driving motor is fixedly connected with a second electric control valve at the bottom end of the transfer box, a closing cover is fixedly connected with the bottom end of the second electric control valve, a fixing rod is fixedly arranged at the bottom end of the closing cover in an annular array, a filter disc is fixedly arranged at the bottom end of all the fixing rods, a reactor is arranged at the bottom end of the closing cover, and the top end of the reactor and the bottom end of the closing cover are in contact with each other. When working, a filter cake hydrochloric acid solution is transported into the reactor through the evaporation box, evaporated in the evaporation box, and then transported into the transfer box, adjusted in pH value in the transfer box, and then transported into the closing cover. The driving motor drives a driving shaft to rotate, and the filter cake solution is accommodated by the reactor.

[0008] Furthermore, an input pipe is fixedly connected to the center of the top of the evaporator box, a heating plate is fixed to the inner bottom of the evaporator box, a heat conducting plate is fixed on the top of the heating plate, the heat conducting plate is fixed on the inner wall of the evaporator box, the output pipe is arranged above the heat conducting plate, an electric control valve 1 is fixed to the middle of the peripheral side of the output pipe, the evaporator box transports the solution after the filter cake crystallization into it through the input pipe, transfers the heat of the heating plate through the heat conducting plate, and evaporates the solution after the filter cake crystallization.

[0009] Furthermore, a pH meter is fixed through the top of the transfer box, and a connecting pipe is fixedly connected to the front of the top of the transfer box. The transfer box measures the pH value of the solution passing through it by the pH meter.

[0010] Furthermore, a driving shaft is fixed to the output end of the driving motor, and the driving shaft is inserted into one side of the transfer box. A stirring frame is fixed to the end of the driving shaft away from the driving motor, and the stirring frame is arranged in the transfer box. The driving motor drives the driving shaft to rotate, driving the stirring frame to stir the evaporated filter cake solution in the transfer box.

[0011] Furthermore, a scraper ring is fixed at the top edge of the filter disc, and the filter disc and the scraper ring are both movably connected in the reactor, and the filter disc scrapes the crystals on the inner wall of the reactor through the scraper ring.

[0012] Furthermore, a fixing ring is fixed on the upper outer peripheral surface of the reactor, an electric push rod is symmetrically fixed to the bottom end of the fixing ring, a one-way air inlet pipe is fixedly connected to the lower peripheral side of the reactor between the two electric push rods, and a vortex tube is fixedly connected to the end of the one-way air inlet pipe away from the reactor. The reactor is connected to the electric push rod via the fixing ring, and the reactor is driven to rise and fall by the electric push rod.

[0013] The utility model has the following beneficial effects:

[0014] 1. The utility model solves the problem that the yield of pyrazine-2,3-dicarboxylic acid is not high enough after direct extraction by arranging an evaporation box, a transfer box and a driving motor. The hydrochloric acid solution of the recrystallized filter cake enters the evaporation box through an input pipe, and the hydrochloric acid solution of the recrystallized filter cake is generated by evaporation through a heating plate, and then is guided to the hydrochloric acid solution of the recrystallized filter cake through a heat conduction plate. The hydrochloric acid solution of the recrystallized filter cake is further evaporated, so that the concentration of the finished product in the hydrochloric acid solution is further improved, and secondary crystallization can be performed to increase the yield of the finished product.

[0015] 2. The utility model solves the problem that the crystals of pyrazine-2,3-dicarboxylic acid repeatedly extracted after recrystallization are easily adhered to the reactor, resulting in inconvenient crystal separation by arranging a driving motor, a closing cover and a reactor. When separating the crystals, the electric push rod is started, and the electric push rod drives the fixed ring to descend, driving the reactor to descend. During the descent of the reactor, the filter disc rises in the reactor, and the filtrate after recrystallization is filtered through the filter disc. The filter disc scrapes the crystallized pyrazine-2,3-dicarboxylic acid on the inner wall of the reactor through a scraping ring until the reactor and the filter disc are separated. After the crystallized pyrazine-2,3-dicarboxylic acid is fully filtered, it is removed from the filter disc, and the filtrate after recrystallization in the reactor is simultaneously extracted, so that the crystal separation of pyrazine-2,3-dicarboxylic acid repeatedly extracted after recrystallization is more convenient. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for describing the embodiments are briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0017] Figure 1 It is a stereoscopic diagram of the assembly structure of a reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid;

[0018] Figure 2 It is a three-dimensional diagram of the sectional structure of the evaporation box;

[0019] Figure 3 This is a three-dimensional diagram of the transfer box structure;

[0020] Figure 4 It is a three-dimensional diagram of the drive motor structure;

[0021] Figure 5 It is a three-dimensional diagram of the closed cover structure;

[0022] Figure 6 It is a three-dimensional diagram of the reactor structure.

[0023] Reference numerals:

[0024] 1. Evaporation box; 101. Input pipe; 102. Heating plate; 103. Heat conducting plate; 104. Output pipe; 105. Electric control valve 1; 2. Transfer box; 201. pH meter; 202. Connecting pipe; 3. Driving motor; 301. Driving shaft; 302. Stirring frame; 4. Closing cover; 401. Electric control valve 2; 402. Fixed rod; 403. Filter plate; 404. Scraping ring; 5. Reactor; 501. Fixed ring; 502. Electric push rod; 503. One-way air inlet pipe; 504. Vortex tube. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model. Specific embodiment 1

[0027] See also Figure 1-6 The utility model is a reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid, comprising an evaporation box 1, a transfer box 2, a driving motor 3, a closing cover 4 and a reaction kettle 5. One side of the evaporation box 1 is fixedly connected with an output pipe 104, the evaporation box 1 evaporates the recrystallized filter cake hydrochloric acid solution entering therein, and outputs the recrystallized filter cake hydrochloric acid solution after evaporation in the evaporation box 1 for half an hour to the transfer box 2 through the output pipe 104, the output pipe 104 is fixedly connected with the transfer box 2 at one end away from the evaporation box 1, the recrystallized filter cake hydrochloric acid solution output from the output pipe 104 is transferred through the transfer box 2, and hydrochloric acid is added to adjust the pH value, the transfer box 2 is fixedly connected with a driving motor 3 at the lower part of the side close to the evaporation box 1, and the driving motor 3 is used to drive the filter cake hydrochloric acid solution output from the output pipe 104. The driving shaft 301 is driven to rotate, and the bottom end of the transfer box 2 is fixedly connected to the electric control valve 2 401, and the bottom end of the electric control valve 2 401 is fixedly connected to the closing cover 4. The hydrochloric acid solution of the recrystallized filter cake in the transfer box 2 is controlled by the electric control valve 2 401 to be transported to the closing cover 4, and the bottom end of the closing cover 4 is fixed with fixed rods 402 in a circular array, and the bottom ends of all the fixed rods 402 are commonly fixed with a filter disc 403, and the fixed rods 402 fix the filter disc 403 and the closing cover 4 together. A reactor 5 is arranged at the bottom end of the closing cover 4, and the top end of the reactor 5 is abutted against the bottom end of the closing cover 4. After the hydrochloric acid solution of the recrystallized filter cake enters the reactor 5 through the electric control valve 2 401, it is cooled and recrystallized by the reactor 5.

[0028] Specifically, an input pipe 101 is fixedly connected to the center of the top of the evaporation box 1, a heating plate 102 is fixed to the inner bottom of the evaporation box 1, a heat conducting plate 103 is fixed to the top of the heating plate 102, the heat conducting plate 103 is fixed to the inner wall of the evaporation box 1, an output pipe 104 is arranged above the heat conducting plate 103, and an electric control valve 105 is fixed to the middle of the peripheral side of the output pipe 104. The hydrochloric acid solution of the recrystallized filter cake enters the evaporation box 1 through the input pipe 101, and the hydrochloric acid solution of the recrystallized filter cake is generated by the heating plate 102, and then guided to the hydrochloric acid solution of the recrystallized filter cake through the heat conducting plate 103, so as to further evaporate the hydrochloric acid solution of the recrystallized filter cake.

[0029] Furthermore, a pH meter 201 is fixed through the top of the transfer box 2, and a connecting pipe 202 is fixedly connected to the front of the top of the transfer box 2. The transfer box 2 measures the pH of the hydrochloric acid solution of the recrystallized filter cake passing therethrough through the pH meter 201. When the pH of the hydrochloric acid solution of the recrystallized filter cake is greater than 2, hydrochloric acid is introduced into the transfer box 2 through the connecting pipe 202, and the pH of the hydrochloric acid solution of the recrystallized filter cake is adjusted to 2, thereby completing the adjustment.

[0030] Furthermore, a driving shaft 301 is fixed to the output end of the driving motor 3, and the driving shaft 301 is inserted through one side of the transfer box 2. A stirring frame 302 is fixed to the end of the driving shaft 301 away from the driving motor 3. The stirring frame 302 is arranged in the transfer box 2. The driving motor 3 drives the driving shaft 301 to rotate, and drives the stirring frame 302 to rotate, so that the hydrochloric acid solution of the recrystallized filter cake and the hydrochloric acid for adjusting the pH in the transfer box 2 are evenly stirred.

[0031] The operation process of this embodiment is as follows: during operation, the recrystallized filter cake hydrochloric acid solution is introduced into the evaporation box 1 through the input pipe 101, the evaporated recrystallized filter cake hydrochloric acid solution is generated through the heating plate 102, and then guided to the recrystallized filter cake hydrochloric acid solution through the heat conducting plate 103, and the recrystallized filter cake hydrochloric acid solution is further evaporated. After evaporation for half an hour, the electric control valve 105 is started, and the recrystallized filter cake hydrochloric acid solution further evaporated in the evaporation box 1 is output to the transfer box 2 through the output pipe 104, and the pH of the recrystallized filter cake hydrochloric acid solution passing therethrough is measured by the pH meter 201. When the pH of the recrystallized filter cake hydrochloric acid solution is greater than 2, hydrochloric acid is introduced into the transfer box 2 through the connecting pipe 202, and the pH of the recrystallized filter cake hydrochloric acid solution is adjusted to 2. In the process of adjusting the pH, the driving motor 3 drives the driving shaft 301 to rotate, driving the stirring frame 302 to rotate, so that the recrystallized filter cake hydrochloric acid solution in the transfer box 2 and the hydrochloric acid for adjusting the pH are evenly stirred. Specific embodiment 2

[0033] See also Figure 1 , 56. On the basis of the specific embodiment 1, a scraper ring 404 is fixed at the top edge of the filter disc 403. The filter disc 403 and the scraper ring 404 are movably connected in the reactor 5. The filter disc 403 scrapes the crystallized pyrazine-2,3-dicarboxylic acid on the inner wall of the reactor 5 through the scraper ring 404.

[0034] Specifically, a fixing ring 501 is fixed on the upper outer peripheral surface of the reactor 5, and an electric push rod 502 is symmetrically fixed to the bottom end of the fixing ring 501. A one-way air inlet pipe 503 is fixedly connected to the lower peripheral side of the reactor 5 between the two electric push rods 502, and a vortex tube 504 is fixedly connected to the end of the one-way air inlet pipe 503 away from the reactor 5. The reactor 5 is connected to the electric push rod 502 through the fixing ring 501, and the fixing ring 501 is driven to rise and fall by the electric push rod 502, thereby driving the reactor 5 to rise and fall, and the cold end of the vortex tube 504 is connected to the one-way air inlet pipe 503. After high-pressure air is input into the vortex tube 504, it enters the one-way air inlet pipe 503 and enters the reactor 5 through the one-way air inlet pipe 503, so that the cold air in the vortex tube 504 is input into the reactor 5 to cool and recrystallize the solution in the reactor 5.

[0035] The operation process of this embodiment is as follows: during operation, when the electric control valve 2 401 is opened, the filter cake hydrochloric acid solution after adjusting the pH in the transfer box 2 is input into the closing cover 4, and then enters the reactor 5, and then communicates with the one-way air inlet pipe 503 through the cold end of the vortex tube 504, and then enters the one-way air inlet pipe 503 after being input into the vortex tube 504 by high-pressure air, and then enters the one-way air inlet pipe 503, and enters the reactor 5 through the one-way air inlet pipe 503, so that the cold air in the vortex tube 504 is input into the reactor 5, and the solution in the reactor 5 is cooled and recrystallized, and then the electric push rod is started. 502, the electric push rod 502 drives the fixed ring 501 to descend, driving the reactor 5 to descend. During the process of the reactor 5 descending, the filter disc 403 rises in the reactor 5, and the recrystallized filtrate is filtered through the filter disc 403. The filter disc 403 scrapes the crystallized pyrazine-2,3-dicarboxylic acid on the inner wall of the reactor 5 through the scraping ring 404 until the reactor 5 and the filter disc 403 are separated. After the crystallized pyrazine-2,3-dicarboxylic acid is fully filtered, it is removed from the filter disc 403, and the recrystallized filtrate in the reactor 5 is extracted to complete the work.

[0036] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0037] The preferred embodiments of the utility model disclosed above are only used to help explain the utility model. The preferred embodiments do not describe all the details in detail, nor do they limit the utility model to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the utility model, so that technicians in the relevant technical field can well understand and use the utility model. The utility model is limited only by the claims and their full scope and equivalents.

Claims

1. A reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid, comprising an evaporation box (1), a transfer box (2), a drive motor (3), a closing cover (4) and a reaction kettle (5), characterized in that: One side of the evaporation box (1) is fixedly connected to an output pipe (104), one end of the output pipe (104) away from the evaporation box (1) is fixedly connected to a transfer box (2), a lower portion of the transfer box (2) close to the evaporation box (1) is fixedly connected to a drive motor (3), the bottom end of the transfer box (2) is fixedly connected to an electric control valve 2 (401), the bottom end of the electric control valve 2 (401) is fixedly connected to a closing cover (4), the bottom end of the closing cover (4) is fixedly connected to fixing rods (402) in a circular array, the bottom ends of all the fixing rods (402) are commonly fixed with a filter disc (403), and a reaction kettle (5) is provided at the bottom end of the closing cover (4), and the top end of the reaction kettle (5) and the bottom end of the closing cover (4) are in contact with each other.

2. A reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid according to claim 1, characterized in that: An input pipe (101) is fixedly connected to the center of the top of the evaporation box (1), a heating plate (102) is fixed to the inner bottom of the evaporation box (1), a heat conducting plate (103) is fixed to the top of the heating plate (102), the heat conducting plate (103) is fixed to the inner wall of the evaporation box (1), the output pipe (104) is arranged above the heat conducting plate (103), and an electric control valve (105) is fixed to the middle of the peripheral side of the output pipe (104).

3. A reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid according to claim 1, characterized in that: A pH meter (201) is fixedly passed through the top of the transfer box (2), and a connecting pipe (202) is fixedly connected to the front of the top of the transfer box (2).

4. A reaction solvent re-extraction device for pyrazine-2,3-dicarboxylic acid according to claim 1, characterized in that: A driving shaft (301) is fixed to the output end of the driving motor (3), and the driving shaft (301) is inserted through one side of the transfer box (2). A stirring frame (302) is fixed to the end of the driving shaft (301) away from the driving motor (3), and the stirring frame (302) is arranged in the transfer box (2).

5. The device for re-extracting the reaction solvent of pyrazine-2,3-dicarboxylic acid according to claim 1, characterized in that: A scraper ring (404) is fixed at the top edge of the filter disc (403), and the filter disc (403) and the scraper ring (404) are both movably connected in the reaction kettle (5).

6. The device for re-extracting the reaction solvent of pyrazine-2,3-dicarboxylic acid according to claim 1, characterized in that: A fixing ring (501) is fixed on the upper outer peripheral surface of the reactor (5), and an electric push rod (502) is symmetrically fixed to the bottom end of the fixing ring (501). A one-way air inlet pipe (503) is fixedly connected to the lower peripheral side of the reactor (5) between the two electric push rods (502), and a vortex tube (504) is fixedly connected to the one-way air inlet pipe (503) at one end away from the reactor (5).

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