Synthesis equipment of carboxin

Abstract

The invention provides carboxin synthesis equipment, and relates to the technical field of carboxin synthesis, the carboxin synthesis equipment comprises a graphite tubular reactor used for synthesizing a carboxin intermediate, the graphite tubular reactor comprises a chlorine inlet and a liquid inlet, the chlorine inlet is formed in the side wall of the graphite tubular reactor, and the liquid inlet is formed in the side wall of the graphite tubular reactor; the liquid inlet is formed below the chlorine inlet and is used for conveying an acetoacetanilide raw material; the synthesis kettle is communicated with a bottom pipeline of the graphite tubular reactor and comprises a feeding port, and the feeding port is used for feeding mercaptoethanol, an acid-binding agent and a catalyst. The device is reasonable in structure, reduces the waste treatment burden, saves the cost and facilitates industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carboxin synthesis, and particularly relates to a carboxin synthesis device. BACKGROUND

[0002] Carboxin is a heterocyclic fungicide with systemic action, since its excellent performance and wide application, it occupies an important position in the field of pesticides. The pure product is white needle-like crystal, which is difficult to dissolve in water, but can be dissolved in methanol, acetone, benzene and other organic solvents. The common dosage forms of the fungicide include wettable powder, water suspension and emulsion oil, etc., which are mainly used for preventing and treating sorghum head smut, wheat rust, cotton disease and millet white disease and other crop diseases.

[0003] At present, there are three process routes for synthesizing carboxin: route one ( Figure 1 ) is to take acetoacetanilide, sulfuryl chloride and mercaptoethanol as raw materials, first to obtain chloro by chlorination, then to obtain carboxin by condensation reaction and cyclization reaction. Route two is that acetoacetanilide is first reacted with mercaptoethanol under acidic conditions to generate oxathiole, then oxathiole oxide is obtained by oxidation reaction, and finally carboxin is obtained by dehydration under acidic catalysis. Route three is also to synthesize oxathiole (the same as route two), and then to chlorinate or brominate the sulfur atom, and then to expand the ring by de(chloride or bromide) to obtain carboxin. Because of the large amount of sodium tungstate heavy metal catalyst used in route two, the amount of wastewater is large and difficult to handle, and route three requires drying of the intermediate material and-40 DEG C deep cooling process, so most of the actual industrial production plants adopt the synthesis method of route one.

[0004] However, the equipment used in the synthesis method of route one still has the following problems: in the chlorination reaction process, the atomic utilization efficiency of sulfuryl chloride is significantly low, and the theoretical utilization rate is only 26%, which leads to the conversion of most of the sulfuryl chloride into industrial difficult-to-handle sulfur dioxide and hydrogen chloride gas, resulting in a large amount of industrial waste, increasing the burden of waste treatment. There is an urgent need for a carboxin synthesis device to solve the above problems. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application aims to provide a carboxin synthesis device to solve the problems raised in the background art, which has reasonable structure, reduces the burden of waste treatment, saves cost and is beneficial to industrial production.

[0006] In order to achieve the above-mentioned purpose, the present application is realized by the following technical scheme: a carboxin synthesis device, comprising: The graphite tubular reactor is used for synthesizing an intermediate of carboxim, and comprises a chlorine gas inlet and a liquid inlet, the chlorine gas inlet is arranged on the side wall of the graphite tubular reactor, and the liquid inlet is arranged below the chlorine gas inlet and is used for conveying acetoacetylaniline raw materials. The synthesis kettle is communicated with the bottom pipeline of the graphite tubular reactor, and comprises a feeding port, the feeding port is used for feeding mercaptoethanol, acid-binding agent and catalyst.

[0007] Further, a receiving tank is arranged between the bottom of the graphite tubular reactor and the top of the synthesis kettle through a pipeline, and an air induction component for discharging tail gas left by the synthesized carboxim intermediate is arranged on the receiving tank. The air induction component comprises a hollow arc-shaped plate arranged on the inner wall of the receiving tank, a plurality of air suction holes are arranged on the bottom of the hollow arc-shaped plate, an air induction pipe is arranged on the top of the receiving tank and is communicated with the hollow arc-shaped plate, and the air induction pipe is connected with an external air induction fan. The pipeline on the top of the receiving tank penetrates the hollow arc-shaped plate.

[0008] Further, an adjusting valve, a precision flow meter and a chlorine gas buffer tank are sequentially arranged on the end of the chlorine gas inlet through a pipeline.

[0009] Further, a feeding switch valve, a quantitative metering pump and a mixing kettle are sequentially arranged on the end of the liquid inlet through a pipeline. The mixing kettle is used for mixing and dissolving organic solvents and acetoacetylaniline raw materials.

[0010] Further, a discharging valve and a material output pump are sequentially arranged on the pipeline between the bottom of the receiving tank and the top of the synthesis kettle.

[0011] Further, a circulating switch valve for sending the material flowing out of the receiving tank to the inlet of the quantitative metering pump is arranged on the pipeline between the receiving tank and the discharging valve through a pipeline.

[0012] Further, the graphite tubular reactor comprises a shell, a pair of fixed tube plates are arranged in the shell from top to bottom, a plurality of reaction membrane tubes are arranged on the pair of fixed tube plates and penetrate the fixed tube plates, a liquid overflow ring communicated with the liquid inlet is arranged between the inner side wall of the shell and the top of the uppermost fixed tube plate, a plurality of overflow holes are arranged on the top of the liquid overflow ring, a flow baffle for guiding the raw materials entering from the liquid inlet is arranged in the liquid overflow ring, a liquid outlet is arranged on the bottom of the shell and is communicated with the synthesis kettle through a pipeline. The chlorine gas inlet is arranged on the side wall of the shell and is above the liquid overflow ring.

[0013] Further, the opposite two side walls of the shell are respectively provided with a cooling liquid inlet and a cooling liquid outlet, the cooling liquid outlet is located above the cooling liquid inlet, the cooling liquid inlet and the cooling liquid outlet are located between the pair of fixed tube plates, and the end of the cooling liquid inlet is provided with a cooling liquid inlet valve through a pipeline.

[0014] Further, the shell is internally provided with a baffle plate located between the pair of fixed tube plates.

[0015] Further, the side wall of the shell is provided with a standby gas outlet located below the lowermost fixed tube plate.

[0016] Beneficial effects: The present application carries out chlorination reaction on acetoacetanilide raw material dissolved in organic solvent and chlorine through a graphite tubular reactor to obtain carboxin intermediate, then sends the carboxin intermediate to the inside of a synthesis kettle, pours mercaptoethanol and acid-binding agent into the synthesis kettle to carry out condensation reaction, after the reaction, adds a catalyst to carry out reflux dehydration cyclization reaction, after the reaction, carries out crystallization and purification to obtain carboxin. BRIEF DESCRIPTION OF DRAWINGS

[0017] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments with reference to the attached drawings: Figure 1 A schematic diagram of a carboxin synthesis route of the prior art; Figure 2 A schematic diagram of a carboxin synthesis route of the present application; Figure 3 A structural schematic diagram of a carboxin synthesis device according to an embodiment of the present application; Figure 4 A structural schematic diagram of a graphite tubular reactor in a carboxin synthesis device according to an embodiment of the present application; Figure 5 A structural schematic diagram of a connection between a receiving tank and an air induction assembly in a carboxin synthesis device according to an embodiment of the present application; Figure 6 A structural schematic diagram of a carboxin synthesis device according to an embodiment of the present application; Figure 5 An enlarged view of A in the structural schematic diagram of the carboxin synthesis device according to the embodiment of the present application.

[0018] Wherein, 1, mixing kettle; 2, quantitative metering pump; 3, feed switch valve; 4, graphite tube reactor; 41, shell; 411, cooling liquid inlet valve; 42, liquid overflow ring; 421, overflow hole; 43, flow barrier plate; 44, fixed tube plate; 45, reaction membrane tube; 46, baffle; 47, cooling liquid inlet; 48, cooling liquid outlet; 49, standby gas outlet; 410, liquid outlet; 5, receiving tank; 6, circulating switch valve; 7, chlorine buffer tank; 8, precision flowmeter; 9, regulating valve; 10, air induction assembly; 101, hollow arc plate; 102, air suction hole; 103, air induction pipe; 11, discharge valve; 12, material output pump; 13, synthesis kettle; 14, chlorine inlet; 15, liquid inlet.

[0019] The accompanying drawings are used to provide further understanding of the embodiments, and constitute a part of the specification, which are used to explain the embodiments together with the embodiments, and do not constitute a limitation on the embodiments. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection.

[0021] In the description of the embodiments, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the embodiments and simplifying the description, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments.

[0022] Reference Figure 1 At present, the synthesis process of carboxin uses acetoacetanilide (raw material I) and sulfuryl chloride to react, then adds mercaptoethanol to react, and then dehydrates in an acidic environment to obtain the product. However, the existing process has the following problems: 1. In the process of synthesizing II from I, the atom utilization efficiency of sulfuryl chloride is low, and the theoretical amount is only 26%. Most of the generated sulfur dioxide and hydrogen chloride gas are difficult to handle in industry.

[0023] 2. In order to treat tail gas, a large number of tail gas absorption devices need to be matched, the manufacturer first absorbs hydrogen chloride gas by using multiple stages of water, and then absorbs sulfur dioxide by using multiple stages of liquid alkali, in this process, there will be sulfuric acid, sulfurous acid and sulfur dioxide in the absorption liquid hydrochloric acid, which will cause many impurities in the absorbed hydrochloric acid, and the unabsorbed hydrogen chloride will react with the liquid alkali in the later stage treatment, resulting in the generation of a mixture of sodium sulfite, sodium sulfate, sodium chloride, water and sodium hydroxide, the high-salt wastewater becomes hazardous waste after three-effect evaporation, and the amount is about 2-2.5 times the amount of product. How to effectively solve the problem of three wastes and do a good job in resource utilization is urgently needed to be solved.

[0024] 3. When using the sulfuryl chloride synthesis process, the water content of the reaction solvent is very low, and when using the recovered solvent, sulfuryl chloride will react violently with water in the solvent to form acid mist, and the solvent generally needs to be treated by rectification when recovered.

[0025] 4. In order to ensure the reaction yield, usually sulfuryl chloride needs to be excessive, and the molar ratio of sulfuryl chloride to raw material I is 1:1.15 excessive, a large amount of excessive raw material will consume a large amount of acid binding agent and intermediate raw material in the subsequent reaction, and at the same time generate impurities and waste gas, so that the process is not clean.

[0026] As shown in Figure 3 , the embodiment of the present application provides a kind of synthesis equipment of carboxim, comprising: Graphite tube reactor 4 is used for the synthesis of carboxim intermediate, including chlorine inlet 14 and liquid inlet 15, chlorine inlet 14 is arranged on the side wall of graphite tube reactor 4, and liquid inlet 15 is arranged below chlorine inlet 14 and is used to transport acetoacetanilide raw material; Synthesis kettle 13 is communicated with the bottom pipeline of graphite tube reactor 4, including feeding port, and the feeding port is used to put mercaptoethanol, acid binding agent and catalyst. The design is that graphite tube reactor 4 is used for chlorination reaction of acetoacetanilide raw material dissolved in organic solvent and chlorine, and carboxim intermediate is obtained, then carboxim intermediate is sent to the inside of synthesis kettle 13, mercaptoethanol, acid binding agent are put into synthesis kettle 13 for condensation reaction, after reaction, catalyst is added for reflux dehydration cyclization reaction after water layer is separated, and carboxim is obtained after crystallization and purification, chlorine is used instead of sulfuryl chloride, and sulfur dioxide does not need to be treated, so that three wastes generated by treating sulfur dioxide are avoided, the generation of three wastes is reduced, the burden of waste treatment is reduced, cost is saved, and industrial production is facilitated.

[0027] Referring to Figure 3 , Figure 5 and Figure 6 , the bottom of graphite tube reactor 4 and the top of synthesis kettle 13 are provided with receiving tank 5 through pipeline, and air induction assembly 10 is arranged on receiving tank 5 for discharging tail gas left over in the synthesis of carboxim intermediate; The air induction assembly 10 comprises a hollow arc-shaped plate 101 arranged on the upper side of the inner wall of the receiving tank 5, a plurality of air suction holes 102 are arranged on the bottom of the hollow arc-shaped plate 101, and an air induction pipe 103 is arranged on the top of the receiving tank 5 and communicates with the hollow arc-shaped plate 101; the air induction pipe 103 is connected with an external air induction fan; The pipeline on the top of the receiving tank 5 penetrates the hollow arc-shaped plate 101. The design facilitates the gas in the receiving tank 5 to be sent to the inside of the air induction pipe 103, and finally discharged from the inside of the receiving tank 5 through the air induction fan. The design ensures that the receiving tank 5 has a micro-negative pressure air induction tail gas destruction through the operation of the external air induction fan, facilitates the discharge of the residual tail gas hydrogen chloride and chlorine from the inside of the receiving tank 5, and the discharged hydrogen chloride and chlorine are subjected to subsequent treatment, so as to avoid the excess chlorine and the intermediate of the dithiocarbamic acid to continue to react to generate impurities; wherein the hollow arc-shaped plate 101 and the plurality of air suction holes 102 increase the area of the discharged tail gas, and facilitate the discharge of the tail gas from the inside of the receiving tank 5.

[0028] Referring to Figure 3 The end of the chlorine inlet 14 is sequentially provided with an adjusting valve 9, a precision flow meter 8 and a chlorine buffer tank 7 through a pipeline. The design facilitates the stable delivery of chlorine to the graphite tube reactor 4 through the adjusting valve 9, the precision flow meter 8 and the chlorine buffer tank 7.

[0029] The end of the liquid inlet 15 is sequentially provided with a feed switch valve 3, a quantitative metering pump 2 and a mixing kettle 1 through a pipeline; The mixing kettle 1 is used for mixing and dissolving the organic solvent and the acetoacetylaniline raw material. The design facilitates the stable delivery of the mixed and dissolved organic solvent and acetoacetylaniline raw material to the inside of the graphite tube reactor 4 through the feed switch valve 3, the quantitative metering pump 2 and the mixing kettle 1.

[0030] The pipeline between the bottom of the receiving tank 5 and the top of the synthesis kettle 13 is sequentially provided with a discharge valve 11 and a material output pump 12. The design facilitates the delivery of the material flowing out of the inside of the receiving tank 5 to the inside of the synthesis kettle 13.

[0031] The pipeline between the receiving tank 5 and the discharge valve 11 is provided with a circulating switch valve 6 for sending the material flowing out of the receiving tank 5 to the inlet of the quantitative metering pump 2 through a pipeline. The design facilitates the backflow of the material flowing out of the inside of the receiving tank 5 to the inlet of the quantitative metering pump 2 and into the inside of the graphite tube reactor 4 for continuous reaction through the circulating switch valve 6.

[0032] Referring to Figure 3 and Figure 4The graphite tubular reactor 4 comprises a shell 41, a pair of fixed tube plates 44 arranged inside the shell 41 from top to bottom, a plurality of reaction membrane tubes 45 arranged through the fixed tube plates 44, a liquid overflow ring 42 arranged between the inner side wall of the shell 41 and the top of the uppermost fixed tube plate 44 and connected with the liquid inlet 15, a plurality of overflow holes 421 arranged at the top of the liquid overflow ring 42, a flow barrier plate 43 arranged inside the liquid overflow ring 42 and used for guiding the raw material entering from the liquid inlet 15, and a liquid outlet 410 arranged at the bottom of the shell 41 and connected with the synthesis kettle 13 through a pipeline; The chlorine inlet 14 is arranged on the side wall of the shell 41 and above the liquid overflow ring 42. In this design, the acetoacetylaniline raw material dissolved in the organic solvent is transported into the shell 41 through the liquid inlet 15, enters the inside of the liquid overflow ring 42, flows upwards under the guidance of the flow barrier plate 43, is sprayed upwards from the plurality of overflow holes 421, improves the uniformity of the dispersion of the raw material, chlorine is introduced into the inside of the shell 41 through the chlorine inlet 14, the upwards flowing raw material is in full contact with the chlorine, then flows into the inside of the reaction membrane tube 45 to react and synthesize the carboxin intermediate, improves the uniformity of the reaction, and finally flows out from the liquid outlet 410.

[0033] Referring to Figure 4 The opposite side walls of the shell 41 are respectively provided with a cooling liquid inlet 47 and a cooling liquid outlet 48, the cooling liquid outlet 48 is arranged above the cooling liquid inlet 47, the cooling liquid inlet 47 and the cooling liquid outlet 48 are both arranged between the pair of fixed tube plates 44, and the end of the cooling liquid inlet 47 is provided with a cooling liquid inlet valve 411 through a pipeline. In this design, the cooling brine is introduced into the inside of the shell 41 by opening the cooling liquid inlet valve 411, the temperature of the material in the inside of the reaction membrane tube 45 is adjusted, and the synthesis of the carboxin intermediate is promoted. The shell 41 is provided with a baffle plate 46 arranged between the pair of fixed tube plates 44, and the side wall of the shell 41 is provided with a standby gas outlet 49 arranged below the lowermost fixed tube plate 44. The rationality of this design is improved.

[0034] Referring to Figures 1-6As an embodiment of the present application: when it is necessary to synthesize carboxin, the organic solvent and acetoacetanilide raw material are mixed and dissolved by the mixing kettle 1, and then the acetoacetanilide raw material dissolved in the organic solvent is stably transported into the liquid overflow ring 42 inside the graphite tubular reactor 4 by the feed switch valve 3, the quantitative metering pump 2 and the mixing kettle 1, flows upward under the guidance of the flow guide plate 43, sprays upward from the plurality of overflow holes 421, and improves the uniformity of the dispersion of the raw material; the chlorine gas is conveniently and stably introduced into the shell 41 of the graphite tubular reactor 4 by the regulating valve 9, the precision flowmeter 8 and the chlorine gas buffer tank 7, the uniformly dispersed and upward flowing raw material is in full contact with the chlorine gas, and then flows into the reaction membrane tube 45 to react and synthesize carboxin intermediates, thereby improving the uniformity of the reaction, and finally flows out from the liquid outlet 410 into the chlorine gas buffer tank 7; wherein the organic solvent is selected from dichloroethane, toluene or a mixture of the two.

[0035] The exhaust fan is connected and works to ensure that the receiving tank 5 has a slight negative pressure to exhaust the residual tail gas hydrogen chloride and chlorine gas out of the receiving tank 5, the discharged hydrogen chloride and chlorine gas are treated subsequently, and the excess chlorine gas is prevented from continuing to react with the carboxin intermediates to generate impurities.

[0036] Finally, the carboxin intermediates are sent to the synthesis kettle 13 inside by the discharge valve 11 and the material output pump 12, mercaptoethanol and acid-binding agent are put into the synthesis kettle 13 for condensation reaction, after the reaction is completed, the water layer is separated, and then a catalyst is added for reflux dehydration cyclization reaction, after the reaction is completed, crystallization and purification are performed to obtain carboxin. The use of chlorine gas instead of sulfuryl chloride eliminates the need for sulfur dioxide treatment, avoids the generation of three wastes in the treatment of sulfur dioxide, reduces the generation of three wastes, reduces the burden of waste treatment, saves costs, and is conducive to industrialized production; wherein the catalyst is p-toluenesulfonic acid or pyridine p-toluenesulfonate, and the acid-binding agent is one of triethylamine, ammonia water, ammonium bicarbonate and sodium carbonate, preferably a saturated aqueous solution of sodium carbonate.

[0037] Referring to Figure 2 and Figure 3 , wherein the above synthesis equipment uses chlorine gas as a chlorinating agent, both chlorine atoms in the chlorine gas molecule participate in the reaction (one enters the product and one generates HCl), the theoretical atomic utilization rate is improved to nearly 100%, thereby the generation amount of by-products (sulfur dioxide and excess HCl) can be reduced from the source, and the pressure of subsequent waste gas treatment is reduced. Moreover, the synthesis process using chlorine gas as a chlorinating agent only generates single HCl gas, which can be directly absorbed by water without additional alkali absorption, thereby avoiding the generation of mixed salt hazardous waste. At the same time, the sensitivity of chlorine gas to water is significantly lower than that of sulfuryl chloride, the solvents suitable for chlorine gas include toluene and dichloroethane, and only a small amount of water needs to be removed by simple distillation during recovery, without the need for deep dehydration, thereby the energy consumption for solvent recovery can be reduced.

[0038] In conclusion, the present application solves the problem of high three wastes and high cost in the synthesis of carboxin by using chlorine instead of sulfuryl chloride as chlorinating reagent, improves the cleanness of the synthesis process of carboxin, and reduces the comprehensive production cost of carboxin.

[0039] It should be noted that, in this text, relational terms such as first and second are used merely to distinguish one entity or action from another, without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises", "comprising", or any other variations thereof, are intended to cover non-exclusive inclusions, so that a process, method, article, or apparatus that comprises a list of elements does not only include those elements, but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0040] The above describes the embodiments, which is not limited, and the drawings only show one of the embodiments, and the actual structure is not limited thereto. In general, if a person skilled in the art is inspired, without departing from the creative purpose, without creative design, similar structure and embodiments of the technical solution are not included in the protection scope.

Claims

1. A device for synthesizing carboxin, characterized by, The application relates to a graphite tubular reactor (4) for synthesizing a carboximide intermediate, which comprises a chlorine gas inlet (14) arranged on the side wall of the graphite tubular reactor (4) and a liquid inlet (15) arranged below the chlorine gas inlet (14) and used for conveying acetoacetanilide raw materials. A synthesis kettle (13) is communicated with the bottom pipeline of the graphite tubular reactor (4) and comprises a feeding opening used for feeding mercaptoethanol, an acid-binding agent and a catalyst. A receiving tank (5) is arranged between the bottom of the graphite tubular reactor (4) and the top of the synthesis kettle (13) through a pipeline, and an air induction assembly (10) for discharging tail gas left by the synthesized carboximide intermediate is arranged on the receiving tank (5).

2. The synthetic device of carboxin according to claim 1, wherein, The air induction assembly (10) comprises a hollow arc-shaped plate (101) arranged on the inner wall of the receiving tank (5) and a plurality of air suction holes (102) arranged on the bottom of the hollow arc-shaped plate (101), an air induction pipe (103) is arranged on the top of the receiving tank (5) and is communicated with the hollow arc-shaped plate (101), and the air induction pipe (103) is connected with an external air induction fan. The pipeline on the top of the receiving tank (5) penetrates the hollow arc-shaped plate (101). The end of the chlorine gas inlet (14) is sequentially provided with an adjusting valve (9), a precision flowmeter (8) and a chlorine gas buffer tank (7) through pipelines.

3. The synthetic device of carboxin according to claim 1, wherein, The end of the liquid inlet (15) is sequentially provided with a feeding switch valve (3), a quantitative metering pump (2) and a mixing kettle (1) through pipelines.

4. The synthetic device of carboxin according to claim 2, wherein, The mixing kettle (1) is used for mixing and dissolving organic solvents and acetoacetanilide raw materials. A discharging valve (11) and a material output pump (12) are sequentially arranged on the pipeline between the bottom of the receiving tank (5) and the top of the synthesis kettle (13).

5. The synthetic device of carboxin according to claim 4, wherein, A circulating switch valve (6) for sending the material flowing out of the receiving tank (5) to the inlet of the quantitative metering pump (2) is arranged on the pipeline between the receiving tank (5) and the discharging valve (11) through a pipeline.

6. The synthetic device of carboxin according to claim 5, wherein, The graphite tubular reactor (4) comprises a shell (41), a pair of fixed tube plates (44) arranged from top to bottom in the shell (41), a plurality of reaction membrane tubes (45) penetratingly arranged on the fixed tube plates (44), a liquid overflow ring (42) arranged between the inner side wall of the shell (41) and the top of the uppermost fixed tube plate (44) and communicated with the liquid inlet (15), a plurality of overflow holes (421) arranged on the top of the liquid overflow ring (42), a flow baffle (43) arranged in the liquid overflow ring (42) and used for guiding the raw materials entering from the liquid inlet (15), and a liquid outlet (410) arranged on the bottom of the shell (41) and communicated with the synthesis kettle (13) through a pipeline.

7. The synthetic device of carboxin according to claim 1, wherein, The chlorine gas inlet (14) is arranged on the side wall of the shell (41) and above the liquid overflow ring (42). ​ 8. The synthetic device of carboxin according to claim 7, wherein, The opposite side walls of the shell (41) are respectively provided with a cooling liquid inlet (47) and a cooling liquid outlet (48), the cooling liquid outlet (48) is located above the cooling liquid inlet (47), the cooling liquid inlet (47) and the cooling liquid outlet (48) are located between the pair of fixed tube plates (44), and the end of the cooling liquid inlet (47) is provided with a cooling liquid inlet valve (411) through a pipeline.

9. The synthetic device of carboxin according to claim 7, wherein, The shell (41) is internally provided with a baffle (46) located between the pair of fixed tube plates (44).

10. The synthetic device of carboxin according to claim 7, wherein, The side wall of the shell (41) is provided with a standby gas outlet (49) located below the lowermost fixed tube plate (44).

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