Device and method for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile

Abstract

The present invention provides a device for continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-nitrile, including a first circulating pump, a first plate heat exchanger, a second circulating pump, a second plate heat exchanger and an oscillating flow spiral baffle reactor connected in sequence, the oscillating flow spiral baffle reactor includes a shell with a holding space, a raw material inlet, a raw material outlet and a baffle arranged in the holding space, the baffle is a baffle, and the two ends of the baffle are respectively connected to the raw material inlet and the raw material outlet, and the baffle cuts the holding space into a continuous bending structure. Compared with the related art, the device for continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-nitrile provided by the present invention has a short reaction time, and the reaction process is easy to control, and there are few by-products and a high product yield.

Description

[Technical field]

[0001] The invention relates to a reactor, in particular to a device and a method for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile. [Background technology]

[0002] 4-Bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile is an important intermediate of aromatic pyrrole insecticides and acaricides bromofenac and chlorfenac. The main synthesis method is to synthesize it through bromination reaction of 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile and bromine.

[0003] The intermittent synthesis method is generally used in industry. This process has the advantages of simple operation and low cost, but it also has disadvantages such as slow reaction speed, excessive amount of raw material bromine, large amount of waste acid produced, and high safety risks.

[0004] Therefore, it is necessary to provide a new device and method for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile to solve the above problems. [Summary of the invention]

[0005] The technical problem to be solved by the present invention is that the prior art has the disadvantages of slow reaction speed, excessive amount of raw material bromine, large amount of waste acid, high safety risk, etc., and the present invention provides a device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile. At the same time, the present invention also provides a method for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile.

[0006] A device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile comprises a first circulation pump, a first plate heat exchanger, a second circulation pump, a second plate heat exchanger and an oscillating flow spiral baffle reactor which are connected in sequence. The oscillating flow spiral baffle reactor comprises a shell with a containing space, a raw material inlet and a raw material outlet which are opened in the shell, and a baffle mounted in the containing space. The baffle is a baffle, and both ends of the baffle are respectively connected to the raw material inlet and the raw material outlet, and the baffle cuts the containing space into a continuous bending structure.

[0007] Preferably, the baffle is a spiral baffle arranged along the length direction of the shell, the raw material inlet is arranged at the lower end of the shell, and the raw material outlet is arranged at the upper end of the shell.

[0008] Preferably, it also includes a heat exchange component, which includes a first support plate and a second support plate arranged opposite to each other, a plurality of heat exchange tubes connecting the first support plate and the second support plate, and a heat exchange agent inlet and a heat exchange agent outlet opened in the shell, the first support plate is arranged on the side of the raw material inlet away from the raw material outlet, the second support plate is arranged on the side of the raw material outlet away from the raw material inlet, the first support plate and the shell enclose a first flow space, the second support plate and the shell enclose a second flow space, the heat exchange agent inlet is connected to the first flow space, and the heat exchange agent outlet is connected to the second flow space.

[0009] Preferably, the heat exchanger inlet is arranged close to the raw material inlet, and the heat exchanger outlet is arranged close to the raw material outlet.

[0010] A method for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile, firstly providing a first circulation pump, a first plate heat exchanger, a second circulation pump, a second plate heat exchanger and an oscillating flow spiral baffle reactor which are connected in sequence, and the synthesis method comprises the following steps:

[0011] Step 1: adding 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution and bromine solution into the first circulation pump after metering and mixing to form a first mixed solution;

[0012] Step 2: introducing the first mixed solution into the first plate heat exchanger, and forming a second mixed solution after a period of reaction and heat exchange, introducing a portion of the second mixed solution into the first circulation pump to mix with the first mixed solution, and introducing another portion of the second mixed solution into the second circulation pump;

[0013] Step 3: adding measured hydrogen peroxide into the second circulation pump to mix with the second mixed solution to form a third mixed solution;

[0014] Step 4: introducing the third mixed solution into the second plate heat exchanger to form a fourth mixed solution after a period of reaction and heat exchange, introducing a portion of the fourth mixed solution into the second circulation pump to mix with the third mixed solution, and introducing another portion of the fourth mixed solution into the oscillating flow spiral baffle reactor;

[0015] Step 5: The fourth mixed solution is reacted in the oscillating flow spiral baffle reactor to obtain an aqueous solution containing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile.

[0016] Preferably, the solvent of the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution is methanol.

[0017] Preferably, the operating temperature of the first circulation pump and the first plate heat exchanger is from room temperature to 40° C., and the reaction time is 0.2-1 h.

[0018] Preferably, the operating temperature of the second circulation pump and the second plate heat exchanger is 60-70° C., and the reaction time is 0.2-0.5 h.

[0019] Preferably, the operating temperature of the oscillating flow spiral baffle reactor is 60-70° C., and the reaction time is 2-3 h.

[0020] Preferably, in step 2, the ratio of the second mixed solution introduced into the first circulation pump to the second mixed solution introduced into the second circulation pump is 1-10:1; in step 4, the ratio of the fourth mixed solution introduced into the second circulation pump to the fourth mixed solution introduced into the oscillating flow spiral baffle reactor is 1-10:1.

[0021] Compared with the related art, the device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile of the present invention designs the baffle of the oscillating flow spiral baffle reactor as a baffle, so that the reaction material moves back and forth after entering from the raw material inlet, so that the reaction material has a more uniform residence time at a lower flow rate, thereby increasing the heat exchange area per unit volume; by arranging the heat exchange component, the contact area between the reaction material and the heat exchange tube becomes larger, further improving the heat exchange efficiency of the oscillating flow spiral baffle reactor; at the same time, the present invention The method for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile of the invention achieves the purpose of continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile by respectively setting a reflux program in step 2 and step 4, and by setting the reflux process, bromine can fully react with 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile to generate, which improves the generation efficiency of the 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile on the one hand and reduces the input amount of bromine on the other hand; by using methanol as the The solvent of the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution is methanol, which has excellent solubility and can dissolve more bromine than other solvents; in step 2, by setting the ratio of the second mixed solution introduced into the first circulation pump to the second mixed solution introduced into the second circulation pump to 5:1, that is, controlling a small amount of the second mixed solution to enter the lower program, so that most of the second mixed solution continues to react and exchange heat in the first plate heat exchanger, ensuring that the 4-bromo-2-chloro-5-trifluoromethylpyrrole Similarly, in step 4, by controlling a small amount of the fourth mixed solution to enter the next-level program, the hydrobromic acid generated during the bromination reaction can fully react with the hydrogen peroxide, and the hydrobromic acid is oxidized to bromine and continues to react with the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile in the fourth mixed solution to generate the 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile, further improving the purity of the 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile, thereby achieving the technical effect of less by-products and high product yield.

Brief Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work, among which:

[0023] Figure 1A block diagram of a synthesis device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile provided by the present invention;

[0024] Figure 2 A schematic diagram of the three-dimensional structure of an oscillating flow spiral baffle reactor of a synthesis device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile provided by the present invention;

[0025] Figure 3 for Figure 2 A schematic diagram of the three-dimensional structure of the baffle of the oscillating flow spiral baffle reactor shown;

[0026] Figure 4 for Figure 2 The three-dimensional structural schematic diagram of the heat exchange component of the oscillating flow spiral baffle reactor is shown. [Specific implementation method]

[0027] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in 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.

[0028] See also Figure 1 , Figure 1 The block diagram of a synthesis device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile disclosed in the present invention. The synthesis device 1000 for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile comprises a first circulation pump 100, a first plate heat exchanger 200, a second circulation pump 300, a second plate heat exchanger 400 and an oscillating flow spiral baffle reactor 500 which are connected in sequence.

[0029] The first circulation pump 100 includes two first feed ports 110, a first circulation port 130 and a first discharge port 150. In this embodiment, the two first feed ports 110 are used to add 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution and bromine solution respectively.

[0030] The first plate heat exchanger 200 includes a second material inlet 210, a second circulation port 230 and a second material outlet 250. The second material inlet 210 is connected to the first material outlet 150, and the second circulation port 230 is connected to the first circulation port 130, and the flow direction is only from the second circulation port 230 to the first circulation port 130.

[0031] Specifically, in this embodiment, the ratio of the opening area of ​​the second circulation port 230 to the opening area of ​​the second discharge port 250 is 5: 1. By controlling the opening areas of the second circulation port 230 and the second discharge port 250, it is ensured that only a small portion of the reaction material can flow into the lower process, so that the reaction material can react more fully in the first circulation pump 100 and the first plate heat exchanger 200.

[0032] The second circulation pump 300 includes two third feed ports 310, a third circulation port 330 and a third discharge port 350. In this embodiment, one third feed port 310 is connected to the second discharge port 250, and one third feed port 310 is used to add hydrogen peroxide.

[0033] The second plate heat exchanger 400 includes a fourth material inlet 410, a fourth circulation port 430 and a fourth material outlet 450. The fourth material inlet 410 is connected to the third material outlet 350, and the fourth circulation port 430 is connected to the third circulation port 330, and the flow direction is only from the fourth circulation port 430 to the third circulation port 330.

[0034] Specifically, in this embodiment, the ratio of the opening area of ​​the fourth circulation port 430 to the opening area of ​​the fourth discharge port 450 is 5: 1. By controlling the opening areas of the fourth circulation port 430 and the fourth discharge port 450, it is ensured that only a small portion of the reaction material can flow into the lower process, so that the reaction material can react more fully in the second circulation pump 300 and the second plate heat exchanger 400.

[0035] Please refer to Figures 2 to 4 ,in, Figure 2 A schematic diagram of the three-dimensional structure of an oscillating flow spiral baffle reactor of a synthesis device for continuously synthesizing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile provided by the present invention; Figure 3 for Figure 2 A schematic diagram of the three-dimensional structure of the baffle of the oscillating flow spiral baffle reactor shown; Figure 4 for Figure 2 The 3D schematic diagram of the heat exchange assembly of the oscillating flow spiral baffle reactor is shown. The oscillating flow spiral baffle reactor 500 includes a shell 510 with a receiving space, a raw material inlet 530 opened in the shell 510, a raw material outlet 550, a baffle 570 installed in the receiving space, and a heat exchange assembly 590.

[0036] Preferably, in this embodiment, the housing 510 is cylindrical. Of course, in other embodiments, the housing 510 may also be circular, square, or cylindrical. The raw material inlet 530 and the raw material outlet 550 are respectively provided on the side walls at both ends of the length direction of the housing 510, wherein the raw material inlet 530 is provided at the lower end of the housing 510, and the raw material outlet 550 is provided at the upper end of the housing 510.

[0037] It should be noted that the oscillating flow spiral baffle reactor 500 can be placed horizontally or vertically in the horizontal direction during use. Specifically, in order to make the reaction material flow at a uniform speed in the containing space, in this embodiment, the oscillating flow spiral baffle reactor 500 is placed vertically in the horizontal direction so that the raw material inlet 530 is located below the raw material outlet 550.

[0038] The baffle 570 is a baffle. Specifically, in the present embodiment, the baffle 570 is a spiral baffle arranged along the length direction of the shell 510. The two ends of the baffle 570 are respectively connected to the raw material inlet 530 and the raw material outlet 550, and the baffle 570 cuts the accommodation space into a continuous bending structure. By designing the baffle 570 as a spiral baffle, the reaction material moves back and forth after entering the oscillating flow spiral baffle reactor 500 from the raw material inlet 530. Compared with the linear motion of the related art, the reaction material has a more uniform residence time at a lower flow rate. The spiral baffle allows the reaction material to move along an oblique line in the accommodation space, increases the movement distance of the reaction material in the accommodation space, and then increases the heat exchange area per unit volume. Compared with the vertical baffle, the dead zone of the material flow can be reduced.

[0039] The heat exchange assembly 590 includes a first support plate 591 and a second support plate 593 that are arranged opposite to each other, a plurality of heat exchange tubes 595 connecting the first support plate 591 and the second support plate 593 , and a heat exchange medium inlet 597 and a heat exchange medium outlet 599 opened in the shell 510 .

[0040] Among them, the first support plate 591 is arranged on the side of the raw material inlet 530 away from the raw material outlet 550, the second support plate 593 is arranged on the side of the raw material outlet 550 away from the raw material inlet 530, the first support plate 591 and the shell 510 enclose a first flow space, the second support plate 593 and the shell enclose a second flow space, the heat exchanger inlet 597 is connected to the first flow space, and the heat exchanger outlet 599 is connected to the second flow space.

[0041] Preferably, the first support plate 591 and the second support plate 593 are both perpendicular to the central axis of the shell 510 , and the heat exchanger inlet 597 is arranged close to the raw material inlet 530 , and the heat exchanger outlet 599 is arranged close to the raw material outlet 550 .

[0042] It should be noted that the plurality of heat exchange tubes 595 penetrate the baffle 570, and cooperate with the first support plate 591 and the second support plate 593 to a certain extent to fix the baffle 570. The heat exchanger passes through the heat exchanger inlet 597, the first flow space, the heat exchange tube 595 and the second flow space in sequence, and finally flows out from the heat exchanger outlet 599 for recovery, so that the contact area between the reaction material and the heat exchange tube 595 becomes larger, and the heat exchange efficiency of the oscillating flow spiral baffle reactor 500 is further improved.

[0043] Please refer to Figure 1 The method for continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile disclosed in the present invention comprises the following steps:

[0044] Step 1: adding 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution and bromine solution into the first circulation pump 100 after metering and mixing to form a first mixed solution;

[0045] In step 1, the solvent of the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution is methanol. Since methanol has excellent solubility, more 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile can be dissolved in the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution, thereby improving the reaction efficiency.

[0046] Step 2: introducing the first mixed solution into the first plate heat exchanger 200, forming a second mixed solution after a set reaction and heat exchange time, introducing a portion of the second mixed solution into the first circulation pump 100 to mix with the first mixed solution, and introducing another portion of the second mixed solution into the second circulation pump 300;

[0047] Preferably, in this step, the second mixed solution introduced into the first circulation pump 100 is controlled to be more than the second mixed solution introduced into the second circulation pump 300. By such a design, most of the second mixed solution continues to react and exchange heat in the first plate heat exchanger 200, thereby ensuring the generation efficiency of the 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile.

[0048] Specifically, the ratio of the second mixed solution introduced into the first circulation pump 100 to the second mixed solution introduced into the second circulation pump 300 is 1-10: 1. Preferably, in this embodiment, the ratio of the second mixed solution introduced into the first circulation pump 100 to the second mixed solution introduced into the second circulation pump 300 is 5:1.

[0049] Step 3: adding measured hydrogen peroxide into the second circulation pump 300 to mix with the second mixed solution to form a third mixed solution;

[0050] Because the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile produces hydrobromic acid when bromine undergoes bromination reaction, resulting in a reduction in product yield. In this step, by adding hydrogen peroxide into the second circulating pump 300, hydrogen peroxide reacts with hydrobromic acid to generate bromine and continues to react with the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile in the fourth mixed solution to generate the 4-bromo-2-to-chloro-5-trifluoromethylpyrrole-3-carbonitrile, further improving the purity of the 4-bromo-2-to-chloro-5-trifluoromethylpyrrole-3-carbonitrile, achieving a technical effect of less by-product and high product yield.

[0051] Step 4: introducing the third mixed solution into the second plate heat exchanger 400, and forming a fourth mixed solution after a period of reaction and heat exchange, introducing a portion of the fourth mixed solution into the second circulation pump 300 to mix with the third mixed solution, and introducing another portion of the fourth mixed solution into the oscillating flow spiral baffle reactor 500;

[0052] Preferably, in this step, the fourth mixed solution introduced into the second circulation pump 300 is controlled to be more than the fourth mixed solution introduced into the oscillating flow spiral baffle reactor 500. By such a design, the hydrobromic acid generated during the bromination reaction can fully react with the hydrogen peroxide, and the hydrobromic acid is oxidized into bromine and continues to react with the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile in the fourth mixed solution to generate the 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile.

[0053] Specifically, the ratio of the fourth mixed solution introduced into the second circulation pump 300 to the fourth mixed solution introduced into the oscillating flow spiral baffle reactor 500 is 1-10: 1. Preferably, in this embodiment, the ratio of the fourth mixed solution introduced into the second circulation pump 300 to the fourth mixed solution introduced into the oscillating flow spiral baffle reactor 500 is 5:1.

[0054] Step 5: The fourth mixed solution is reacted in the oscillating flow spiral baffle reactor 500 to obtain an aqueous solution containing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile.

[0055] Preferably, in this embodiment, the operating temperature of the first circulation pump 100 and the first plate heat exchanger 200 is from room temperature to 40° C., and the reaction time is 0.2-1 h;

[0056] The operating temperature of the second circulation pump 300 and the second plate heat exchanger 400 is 60-70° C., and the reaction time is 0.2-0.5 h;

[0057] The operating temperature of the oscillating flow spiral baffle reactor 500 is 60-70° C., and the reaction time is 2-3 hours.

[0058] The above steps are used to continuously synthesize 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile, and the reaction yield is stably improved by about 3% compared with the batch reaction yield. At the same time, two reflux procedures are set so that bromine can be fully reacted in the device, thereby reducing the input amount of bromine. Specifically, the above steps are used to continuously synthesize 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile, so that the input amount of bromine is reduced by 40% to 45%.

[0059] Specifically, the following provides specific experimental data for the continuous synthesis of 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile using this method:

[0060] 12 kg of 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile (90%, 0.04 kmol) was added to 120 kg of methanol to dissolve and then added to the first circulation pump 100 after metering. Meanwhile, 4 kg of bromine was added to the first circulation pump 100. The first plate heat exchanger 200 controlled the reaction temperature to be room temperature. The material stayed in the first plate heat exchanger 200 for 0.5 h. Most of the reacted material was circulated back to the first circulation pump 100, and the other part of the material was continuously introduced into the second circulation pump 300.

[0061] 4.5 kg of measured hydrogen peroxide is added to the second circulation pump 300, the second plate heat exchanger 400 controls the reaction temperature to be maintained between 60° C. and 65° C., and the material stays in the second plate heat exchanger 400 for 0.5 h. Most of the reacted material is circulated back to the second circulation pump 300, and the other part of the material continuously enters the oscillating flow spiral baffle reactor 500;

[0062] The temperature of the oscillating flow spiral baffle reactor 500 is controlled to be maintained between 60° C. and 65° C., and the material is continuously reacted in the oscillating flow spiral baffle reactor 500 for 2 hours. After the product is cooled to room temperature, 50% water is added to precipitate a white solid, and the product 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile is obtained after filtering, washing, vacuum drying and other steps.

[0063] The product yield of 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile was calculated to be 93.3%, while the reaction yield of the batch reactor using the prior art was 90.1% under the present conditions. Meanwhile, in the intermittent reaction without the addition of hydrogen peroxide for oxidation, the amount of bromine needs to be increased to 7 kg, so the use of the present method for continuous bromination reduces the amount of bromine by 42.8%.

[0064] Compared with the related art, the device 1000 for continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile of the present invention, by designing the baffle 570 of the oscillating flow spiral baffle reactor 500 as a baffle, allows the reaction material to move back and forth after entering from the raw material inlet 530, so that the reaction material has a more uniform residence time at a lower flow rate, thereby increasing the heat exchange area per unit volume; by providing the heat exchange component 590, the contact area between the reaction material and the heat exchange tube 595 becomes larger, further improving the oscillating flow spiral baffle reactor. The heat exchange efficiency of the reactor 500 is improved; at the same time, the method for continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile of the present invention achieves the purpose of continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile by respectively setting a reflux program in step two and step four, and by setting the reflux process, bromine can be fully reacted with 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile to generate, on the one hand, the generation efficiency of the 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile is improved, and on the other hand, the input amount of bromine is reduced; by adopting Methanol is used as the solvent of the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution, because methanol has excellent solubility and can dissolve more bromine than other solvents; in step 2, by setting the ratio of the second mixed solution introduced into the first circulation pump 100 to the second mixed solution introduced into the second circulation pump 300 to be 5:1, that is, a small amount of the second mixed solution is controlled to enter the lower program, so that most of the second mixed solution continues to react and exchange heat in the first plate heat exchanger 200, ensuring that the 4-bromo-2-chloro -5-trifluoromethylpyrrole-3-carbonitrile generation efficiency; similarly, in step 4, by controlling a small amount of the fourth mixed solution to enter the lower-level program, the hydrobromic acid generated during the bromination reaction can fully react with hydrogen peroxide, the hydrobromic acid is oxidized to bromine and continues to react with 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile in the fourth mixed solution to generate the 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile, further improving the purity of the 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile, achieving the technical effect of less by-products and high product yield.

[0065] The above description is only an implementation mode of the present invention. It should be pointed out that, for ordinary technicians in this field, improvements can be made without departing from the creative concept of the present invention, but these all belong to the protection scope of the present invention.

Claims

1. A method for continuously synthesizing 4-bromo-2-chloro-5-trifluoromethylpyrrole-3-carbonitrile, characterized in that: A first circulation pump, a first plate heat exchanger, a second circulation pump, a second plate heat exchanger and an oscillating flow spiral baffle reactor which are connected in sequence are provided, and a heat exchange component is also provided, the heat exchange component comprising a first support plate and a second support plate which are arranged opposite to each other, a plurality of heat exchange tubes connecting the first support plate and the second support plate, and a heat exchange agent inlet and a heat exchange agent outlet which are opened in a shell of the oscillating flow spiral baffle reactor, the first support plate is arranged at a side of a raw material inlet of the shell away from a raw material outlet of the shell, the second support plate is arranged at a side of the raw material outlet away from the raw material inlet, the first support plate and the shell enclose a first flow space, the second support plate and the shell enclose a second flow space, the heat exchange agent inlet is connected to the first flow space, and the heat exchange agent outlet is connected to the second flow space, The steps include: Step 1: adding 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution and bromine solution into the first circulation pump after metering and mixing to form a first mixed solution; Step 2: introducing the first mixed solution into the first plate heat exchanger, and forming a second mixed solution after a period of reaction and heat exchange, introducing a portion of the second mixed solution into the first circulation pump to mix with the first mixed solution, and introducing another portion of the second mixed solution into the second circulation pump; Step 3: adding measured hydrogen peroxide into the second circulation pump to mix with the second mixed solution to form a third mixed solution; Step 4: introducing the third mixed solution into the second plate heat exchanger to form a fourth mixed solution after a period of reaction and heat exchange, introducing a portion of the fourth mixed solution into the second circulation pump to mix with the third mixed solution, and introducing another portion of the fourth mixed solution into the oscillating flow spiral baffle reactor; Step 5: the fourth mixed solution is reacted in the oscillating flow spiral baffle reactor to obtain an aqueous solution containing 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile, Among them, the working temperature of the first circulation pump and the first plate heat exchanger is room temperature to 40°C, and the reaction time is 0.2-1h; the working temperature of the second circulation pump and the second plate heat exchanger is 60-70°C, and the reaction time is 0.2-0.5h; the working temperature of the oscillating flow spiral baffle reactor is 60-70°C, and the reaction time is 2-3h.

2. The method for continuous synthesis of 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile according to claim 1, characterized in that: The solvent of the 2-(4-chlorophenyl)-5-trifluoromethylpyrrole-3-carbonitrile solution is methanol.

3. The method for continuous synthesis of 4-bromo-2-p-chloro-5-trifluoromethylpyrrole-3-carbonitrile according to claim 1, characterized in that: In step 2, the ratio of the second mixed solution introduced into the first circulation pump to the second mixed solution introduced into the second circulation pump is 1-10:1; in step 4, the ratio of the fourth mixed solution introduced into the second circulation pump to the fourth mixed solution introduced into the oscillating flow spiral baffle reactor is 1-10:1.

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