A reaction device and method for continuously synthesizing trimethyl phosphite

Abstract

The application provides a reaction device and method for continuously synthesizing trimethyl phosphite, and belongs to the technical field of trimethyl phosphite synthesis. The reaction device comprises a raw material tank group, a composite reaction kettle, a solvent tank, a pre-cooler, a water washing kettle, an alkali liquid buffer tank, a layered system and a rectification system. The raw material tank group comprises a methanol tank and a phosphorus trichloride tank. The raw material tank group and the solvent tank are connected with the composite reaction kettle through pipelines via the pre-cooler, and the composite reaction kettle is connected with the water washing kettle through a pipeline. The phosphorus trichloride drop-like feed is efficiently converted into a uniform liquid film by a centrifugal disc, and then the liquid film is converted into a fine jet flow by a spraying ring. The fine jet flow is instantaneously and highly intensively sheared with a strong vortex-shaped methanol / solvent flow formed through a tangential feeding pipe. The secondary intensified mixing mode replaces the macroscopic mixing limitation of a traditional stirred tank, realizes instant and uniform mixing of materials at a micro level, thereby inhibiting a side reaction and effectively improving a reaction rate.

Description

Technical Field

[0001] This invention relates to the field of trimethyl phosphite synthesis technology, and in particular to a reaction apparatus and method for the continuous synthesis of trimethyl phosphite. Background Technology

[0002] Trimethyl phosphite is an important pesticide intermediate. Its industrial production mainly adopts a process using phosphorus trichloride and methanol as raw materials, with the reaction carried out in combination with an acid-binding agent. Currently, the mainstream equipment for synthesizing this product can be divided into two categories: one is the traditional batch reactor, which usually uses an enamel-lined reactor and relies on mechanical stirring to achieve material mixing, belonging to a batch or semi-continuous production process; the other is the microchannel reactor, which uses micron-level channels to achieve rapid mixing and heat transfer, aiming to achieve continuous production.

[0003] However, both of the above-mentioned existing devices and processes have obvious limitations. Traditional batch reactors have low heat transfer efficiency and long reaction time, which can easily lead to an increase in side reactions, restricting further improvement in product yield and purity. Moreover, intermittent operation is not conducive to production safety and automation. Although microchannel reactors have high mixing efficiency, their channels are easily blocked by solid impurities in the raw materials or ammonium salt crystals generated in the reaction. They have poor resistance to disturbances and are difficult to maintain and clean, which seriously affects the long-term stability and scale-up feasibility of continuous production. Therefore, this application provides a reaction apparatus and method for continuous synthesis of trimethyl phosphite to meet the requirements. Summary of the Invention

[0004] The purpose of this invention is to provide a reaction apparatus and method for the continuous synthesis of trimethyl phosphite in order to solve the above-mentioned problems. The apparatus efficiently converts the droplet feed of phosphorus trichloride into a uniform liquid film through a centrifugal disc, and then converts the liquid film into a fine jet through a spray ring. This jet is then subjected to instantaneous and high-intensity shear mixing with the methanol / solvent stream that enters through the tangential feed pipe and forms a strong vortex. This solves the problems mentioned in the background art, such as long reaction time, increased side reactions, easy blockage of channels by solid impurities in the raw materials or ammonium salt crystals generated in the reaction, poor resistance to disturbance, and difficulty in maintenance and cleaning.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A continuous synthesis apparatus for trimethyl phosphite includes a raw material tank group, a composite reactor, a solvent tank, a precooler, a water washing tank, an alkali buffer tank, a stratification system, and a distillation system. The raw material tank group includes a methanol tank and a phosphorus trichloride tank. Both the raw material tank group and the solvent tank are connected to the composite reactor via pipelines through the precooler. The composite reactor is connected to the water washing tank via pipelines through the precooler. The water washing tank is connected to the distillation system via the stratification system. The composite reactor includes a tank body, with a receiving hopper at the bottom of the tank body and a discharge pipe at the bottom of the receiving hopper. The tank is equipped with a coaxially rotating centrifugal disc and a spray ring. The centrifugal disc is used to receive phosphorus trichloride falling vertically and to use the centrifugal force of high-speed rotation to convert the droplet feed into an annular thin liquid film that is thrown outward. The centrifugal disc can efficiently spread the concentrated phosphorus trichloride liquid flow into a uniform thin liquid film, which can increase the surface area of ​​the material and create favorable conditions for subsequent fine mixing. The spray ring is located below the centrifuge disc. The spray ring is used to receive the phosphorus trichloride liquid film falling from above and spray the liquid out in the form of a fine jet under the action of centrifugal force. The spray ring can further break the liquid film into a large number of fine jets and spray them into the reaction area in a dynamic manner, thereby achieving instantaneous and high-intensity mixing with another reaction stream.

[0006] Based on the above scheme, the centrifuge disc has a conical structure with a concave receiving area in the middle. The conical surface of the centrifuge disc is provided with a spiral guide groove connected to the receiving area, and the outer edge is provided with an upward-extending anti-splash flange. The spiral guide groove can guide the liquid to spread evenly and form a liquid film with controllable thickness. The anti-splash flange ensures that the liquid film is effectively guided to the predetermined path and prevents splash loss.

[0007] Furthermore, the spray ring is provided with a receiving groove with a top opening, and the side of the spray ring is provided with multiple downward-sloping micro-holes, which are connected to the receiving groove. The multiple downward-sloping micro-holes can uniformly shear the liquid into a fine jet under the action of centrifugal force, and the tilt angle enhances the penetration and shearing effect between the jet and the vortex flow field in the reaction cavity, promoting deep mixing.

[0008] Based on the above, the opening of the spray ring is provided with a flanged part, both sides of the inner wall of the receiving groove are provided with concave stop parts, and the outer side of the spray ring is provided with an inner groove part. The stop parts can increase the turbulence of the liquid in the receiving groove and promote the uniform distribution of the liquid to each micropore.

[0009] Based on the above, a reaction cavity is formed between the injection ring and the inner wall of the tank. A tangential feed pipe is symmetrically arranged on the outer side of the tank. The inlet of the tangential feed pipe is located inside the reaction cavity. The tangential feed pipe pumps the methanol and solvent mixture into the reaction cavity in a tangential direction, thereby forming a strong forced vortex flow field inside the cavity. This vortex flow field provides a high-intensity shear mixing environment for the phosphorus trichloride jet on the one hand, and drives the reactants to flow downward on the other hand, achieving continuous propulsion.

[0010] Furthermore, a cleaning mechanism is provided inside the tank and located between the centrifugal disc and the spray ring. The cleaning mechanism includes a fixed frame and a scraper installed on its outer side. The fixed frame is fixed on the drive shaft, and the scraper is located inside the reaction chamber. The cleaning mechanism rotates with the shaft, and its scraper can continuously scrape the inner wall of the reaction chamber, effectively preventing the solid by-products generated by the reaction from adhering and scaling, ensuring that the reaction area is unobstructed for a long time, so as to maintain the continuity of production.

[0011] A method for synthesizing trimethyl phosphite using a reaction apparatus for continuous synthesis includes the following steps: S1. Start the drive motor of the composite reactor to make the centrifugal disc and the spray ring rotate. The mixture of methanol in the methanol tank and organic solvent and acid binder in the solvent tank are cooled to the predetermined temperature by the precooler and then combined. The mixture is then pumped into the reaction chamber through the tangential feed pipe to form a vortex flow field flowing downward. S2. After phosphorus trichloride is cooled by a precooler, it is pumped in through the top feed pipe and falls vertically onto a high-speed rotating centrifugal disc, where it is centrifugally dispersed into an annular liquid film and transferred into the spray ring. S3. The phosphorus trichloride liquid film is centrifuged in the spray ring and sprayed out in the form of a jet through micropores, where it mixes and reacts with the methanol and solvent vortex formed in step S1. S4. The reaction products are continuously discharged into the washing kettle through the discharge pipe. At the same time, the alkaline solution in the alkaline solution buffer tank is cooled by the precooler and then pumped into the washing kettle for neutralization and washing. S5. Crude trimethyl phosphite is obtained in the upper layer through a stratification system. After drying, the crude trimethyl phosphite is pumped into a distillation system for distillation to obtain the product trimethyl phosphite.

[0012] Compared with the prior art, the present invention has at least the following beneficial effects: In the above-mentioned scheme, the reaction device for continuous synthesis of trimethyl phosphite provided in this application efficiently converts the droplet feed of phosphorus trichloride into a uniform liquid film through a centrifugal disc, and then converts the liquid film into a fine jet through a spray ring. This jet then undergoes instantaneous and high-intensity shear mixing with the methanol / solvent stream that enters through the tangential feed pipe and forms a strong vortex. This mixing method improves the macroscopic mixing limitations of traditional stirred tanks and achieves instantaneous uniform mixing of materials at the microscopic level, thereby suppressing side reactions and effectively improving the reaction rate. By setting a cleaning mechanism between the centrifuge disc and the spray ring, the scraper can continuously scrape the inner wall of the reaction chamber online, preventing solid byproducts (such as ammonium chloride salt) from depositing and scaling, reducing the problem of easy clogging of equipment such as microchannels, and improving the continuity of the reaction. Attached Figure Description

[0013] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the invention and, together with the specification, further serve to explain the principles of the invention and enable those skilled in the art to practice and use the invention.

[0014] Figure 1 This is a flowchart of the equipment for preparing trimethyl phosphite according to the present invention; Figure 2 This is an overall schematic diagram of the composite reactor of the present invention; Figure 3 This is a partial cross-sectional view of the tank body of the present invention; Figure 4 This is a schematic diagram of the interior of the tank of the present invention; Figure 5 This is a three-dimensional schematic diagram of the centrifuge disc of the present invention; Figure 6 This is a three-dimensional schematic diagram of the injection ring of the present invention; Figure 7 This is a partial cross-sectional view of the injection ring of the present invention; Figure 8 For the present invention Figure 7 Enlarged view of point A in the middle; Figure 9 This is a schematic diagram showing the flow path of phosphorus trichloride after feeding according to the present invention.

[0015] Figure label: 1. Raw material tank group; 2. Composite reaction vessel; 3. Solvent tank; 4. Precooler; 5. Water washing vessel; 6. Alkali buffer tank; 7. Layering system; 8. Distillation system; 21. Tank body; 211. Receiving hopper; 212. Discharge pipe; 213. Top feed pipe; 214. Tangential feed pipe; 22. Insulation cover; 23. Heat exchange circulation pipe; 24. Drive motor; 25. Drive shaft; 26. Centrifugal disc; 261. Receiving area; 262. Spiral guide channel; 263. Anti-splash flange; 27. Spray ring; 271. Receiving groove; 272. Micro-hole; 273. Flanged edge; 274. Stop; 275. Inner groove; 28. Cleaning agencies.

[0016] As shown in the figure, specific structures and devices are marked in the figure to clearly illustrate the structure of the embodiments of the present invention. However, this is only for illustrative purposes and is not intended to limit the present invention to this specific structure, device and environment. Those skilled in the art can adjust or modify these devices and environments according to specific needs. Detailed Implementation

[0017] The following is a detailed description of the reaction apparatus and method for the continuous synthesis of trimethyl phosphite provided by the present invention, with reference to the accompanying drawings and specific embodiments. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments, and those skilled in the art can use other alternative methods to implement some known technologies; moreover, the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.

[0018] It should be noted that the use of terms such as "an embodiment," "an embodiment," "an exemplary embodiment," and "some embodiments" in the specification indicates that the described embodiment may include a specific feature, structure, or characteristic, but not every embodiment necessarily includes that specific feature, structure, or characteristic. Furthermore, when a specific feature, structure, or characteristic is described in connection with an embodiment, implementing such a feature, structure, or characteristic in conjunction with other embodiments (whether explicitly described or not) should be within the knowledge of those skilled in the art.

[0019] Generally, terms can be understood at least partly from their use in context. For example, depending at least partly on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in a singular sense, or a combination of features, structures, or characteristics in a plural sense. Additionally, the term "based on" can be understood not necessarily to convey an exclusive set of factors, but rather, alternatively, depending at least partly on the context, to allow for the presence of other factors that are not necessarily explicitly described.

[0020] It is understood that the meanings of “on”, “above”, and “above” in this invention should be interpreted in the broadest manner, such that “on” means not only “directly on” something, but also includes the meaning of being “on” something with an intervening feature or layer, and that “above” or “above” means not only “on” something, but also includes the meaning of being “on” something without an intervening feature or layer.

[0021] Furthermore, spatially related terms such as “below,” “under,” “lower,” “above,” and “upper” are used herein for convenience to describe the relationship of one element or feature to one or more other elements or features, as illustrated in the accompanying drawings. Spatially related terms are intended to cover different orientations in the use or operation of the device other than those depicted in the accompanying drawings. The device may be oriented in other ways, and the spatially related descriptive terms used herein can be interpreted similarly.

[0022] like Figure 1 As shown, an embodiment of the present invention provides a reaction apparatus for the continuous synthesis of trimethyl phosphite, including a raw material tank group 1, a composite reactor 2, a solvent tank 3, a precooler 4, a water washing tank 5, an alkali buffer tank 6, a stratification system 7, and a distillation system 8. The raw material tank group 1 includes a methanol tank and a phosphorus trichloride tank. The solvent tank 3 is used to store a mixture containing an organic solvent (such as benzene) and an acid-binding agent (such as triethylamine). The precooler 4 is used to cool the raw materials to a suitable reaction temperature to avoid local overheating and side reactions. The raw material tank group 1 and the solvent tank 3 are both connected to the composite reactor 2 via the precooler 4 through pipes. The composite reactor 2 is connected to the water washing tank 5 via pipes. The alkali buffer tank 6 is connected to the water washing tank 5 via the precooler 4 through pipes. The precooled alkali helps to maintain a stable temperature during the water washing process and prevents product decomposition. The water washing tank 5 is connected to the distillation system 8 via the stratification system 7. The stratification system 7 is used to separate the aqueous phase and the organic phase. The distillation system 8 is used to purify the product to obtain high-purity trimethyl phosphite.

[0023] In this embodiment, as Figures 2 to 4 As shown, the composite reactor 2 includes a tank body 21, with a receiving hopper 211 at the bottom of the tank body 21 and a discharge pipe 212 at the bottom of the receiving hopper 211. The receiving hopper 211 has a conical structure, which can smoothly collect the spirally descending reaction material and accelerate its discharge to prevent material accumulation at the bottom. The tank body 21 is equipped with a coaxially rotating centrifugal disc 26 and a spray ring 27. A drive shaft 25 is rotatably connected inside the tank body 21, and a drive motor 24 for driving the drive shaft 25 is located at the top of the tank body 21. All 7 are fixed outside the drive shaft 25. A cleaning mechanism 28 is set inside the tank 21 and between the centrifugal disc 26 and the spray ring 27. The cleaning mechanism 28 includes a fixing frame and a scraper installed on its outside. The fixing frame is fixed on the drive shaft 25, and the scraper is located in the reaction chamber. The cleaning mechanism 28 rotates with the drive shaft 25. The scraper continuously scrapes the inner wall of the tank 21, effectively preventing solid by-products (such as ammonium chloride) generated in the reaction from depositing and scaling on the wall surface, so as to ensure the unobstructed flow of the reaction chamber and maintain the stability of long-term continuous operation. In this embodiment, as Figure 5As shown, the centrifugal disc 26 is used to receive phosphorus trichloride falling vertically, and uses the centrifugal force of high-speed rotation to convert the droplet feed into an annular thin liquid film and throw it outward. The centrifugal disc 26 has a conical structure, with a concave receiving area 261 in the middle, which is used to collect phosphorus trichloride falling from the top feed pipe 213 to avoid feed splashing. The conical surface of the centrifugal disc 26 has a spiral guide groove 262 connected to the receiving area 261. The spiral guide groove 262 can guide the liquid to spread evenly along a specific path to form a liquid film of uniform thickness and enhance the dispersion effect. The outer edge has an upward-extending anti-splash flange 263, which can prevent the liquid from splashing under high-speed centrifugal action and ensure that the liquid film is completely transferred to the spray ring 27 below.

[0024] In this embodiment, as Figures 6 to 8 As shown, the spray ring 27 is located below the centrifugal disc 26. The spray ring 27 is used to receive the phosphorus trichloride liquid film falling from above and, under the action of centrifugal force, sprays the liquid out in the form of a fine jet. The spray ring 27 has a receiving groove 271 with a top opening to receive the liquid film thrown out from the centrifugal disc 26. Its opening design facilitates efficient material reception. Multiple downward-sloping micro-holes 272 are opened on the side of the spray ring 27, and the micro-holes 272 are connected to the receiving groove 271. The downward-sloping design of the micro-holes 272 can make the jet direction more easily merge with the vortex flow field in the reaction chamber, enhancing the mixing intensity. The size and distribution density of the micro-holes 272 can be adjusted according to the specific conditions of the reaction chamber. Adjustments can be made as needed to control the density of the jet and achieve efficient mixing at the microscale. The opening of the jet ring 27 is provided with a flange 273, which helps to guide the liquid film smoothly into the receiving tank 271 and reduce liquid spillage. Both sides of the inner wall of the receiving tank 271 are provided with concave stop portions 274. The stop portions 274 can block the liquid to a certain extent when rotating at high speed, increase the turbulence of the liquid in the receiving tank 271, and promote the uniform distribution of the liquid to each micropore 272. The outer side of the jet ring 27 is provided with an inner groove portion 275, which can constrain the solvent entering tangentially and guide it to swirl downwards, reducing solvent splashing.

[0025] In this embodiment, as Figure 2 , Figure 3 and Figure 9As shown, a top feed pipe 213 is symmetrically arranged on the top of the tank 21. The bottom end of the top feed pipe 213 extends directly above the receiving area 261 to transport phosphorus trichloride into the receiving area 261. The symmetrically arranged feed pipes 213 help to evenly distribute phosphorus trichloride in the receiving area 261 and avoid local accumulation. A reaction cavity is formed between the spray ring 27 and the inner wall of the tank 21. This cavity provides a place for sufficient contact and reaction between the phosphorus trichloride jet and the methanol / solvent vortex. A tangential feed pipe 214 is symmetrically arranged on the outer side of the tank 21. The inlet of the tangential feed pipe 214 is located in the reaction cavity. The tangential feeding method causes the methanol and solvent mixture to form a strong vortex flow field after entering the tank. This flow field not only promotes shear mixing with the phosphorus trichloride jet, but also drives the reactants to flow downward, realizing rapid replacement and continuous propulsion of the materials.

[0026] In this embodiment, as Figure 2 and Figure 3 As shown, a heat exchange circulation pipe 23 is provided on the outside of the tank body 21, and a heat insulation cover 22 is provided on the outside of the tank body 21 and on the outside of the heat exchange circulation pipe 23. The inlet and outlet ends of the heat exchange circulation pipe 23 extend to the outside of the heat insulation cover 22. Cooling medium (such as cold water or cold oil) can be introduced into the heat exchange circulation pipe 23 to remove the heat of reaction in time, control the reaction temperature within a suitable range, and suppress the occurrence of side reactions. The heat insulation cover 22 can reduce the heat exchange between the tank body 21 and the outside world and maintain the stability of the reaction temperature.

[0027] A method for synthesizing trimethyl phosphite using a reaction apparatus for continuous synthesis includes the following steps: S1. Start the drive motor 24 of the composite reactor 2 to make the centrifugal disc 26 and the spray ring 27 rotate. The mixture of methanol in the methanol tank and organic solvent and acid binder in the solvent tank 3 are cooled to a predetermined temperature by the precooler 4 and then combined. The mixture is then pumped into the reaction chamber through the tangential feed pipe 214 to form a vortex flow field flowing downward. S2. After phosphorus trichloride is cooled by the precooler 4, it is pumped in through the top feed pipe 213 and falls vertically onto the high-speed rotating centrifugal disc 26, where it is centrifugally dispersed into an annular liquid film and transferred into the spray ring 27. S3. The phosphorus trichloride liquid film is centrifuged in the spray ring 27 and sprayed out in the form of a jet through the micro-hole 272, where it mixes and reacts with the methanol and solvent mixed vortex formed in step S1. S4. The reaction products are continuously discharged from the discharge pipe 212 into the washing tank 5. At the same time, the alkaline solution in the alkaline solution buffer tank 6 is cooled by the precooler 4 and then pumped into the washing tank 5 for neutralization and washing. S5. Crude trimethyl phosphite is obtained in the upper layer through the layering system 7. After drying, the crude trimethyl phosphite is pumped into the distillation system 8 for distillation to obtain the product trimethyl phosphite.

[0028] Working principle of the invention: Methanol and a mixture containing organic solvents and acid-binding agents are cooled to low temperatures by precoolers 4 and then pumped into the reaction chamber of the composite reactor 2 at a high flow rate through tangential feed pipe 214. The tangential feeding method causes the mixture to form a strong, downward rotating vortex flow field in the chamber. At the same time, phosphorus trichloride is cooled by another precooler 4 and then pumped in quantitatively through top feed pipe 213. The cooled phosphorus trichloride stream falls vertically into the receiving area 261 of the high-speed rotating centrifugal disc 26. Under the action of centrifugal force, the liquid spreads rapidly outward along the conical surface of the centrifugal disk 26 and its spiral guide groove 262, forming a uniform and continuous annular thin liquid film. The anti-splash flange 263 can ensure that the liquid film is effectively guided and thrown away from the edge of the disk. The phosphorus trichloride liquid film thrown out from the centrifugal disk 26 is received by the receiving groove 271 of the synchronously rotating spray ring 27 directly below it. The liquid is driven by centrifugal force in the spray ring 27 and is sheared and broken into a large number of fine droplet jets through numerous downward-sloping micro-holes 272 on the ring wall. These phosphorus trichloride jets meet the strong vortex methanol / solvent flow instantly and achieve instantaneous and high-intensity mixing under shear force and turbulence. Meanwhile, the scraper of the cleaning mechanism 28 rotates with the shaft and continuously scrapes the inner wall of the cavity to prevent the deposition of by-product salts. Phosphorus trichloride and methanol undergo rapid esterification in the reaction chamber in the presence of an acid-binding agent. The heat released by the reaction is promptly removed by the cooling medium in the heat exchange circulation pipe 23 outside the tank 21. Low temperature control can effectively suppress side reactions such as hydrolysis. The reaction mixture flows downward under the influence of the vortex flow field and eventually flows into the receiving hopper 211 and is discharged from the discharge pipe 212. The reaction product is continuously discharged into the washing vessel 5 through the discharge pipe 212. At the same time, the alkaline solution from the alkaline solution buffer tank 6 and cooled by the precooler 4 is pumped into the washing vessel 5 to neutralize the hydrochloric acid and residual phosphorus trichloride generated in the reaction, and is washed with water to remove water-soluble impurities such as inorganic salts. The mixture after washing enters the layering system 7. After standing and layering, the upper organic phase is crude trimethyl phosphite. After drying, the crude product is pumped into the distillation system 8. The residual solvent, water and light and heavy components are removed by distillation to finally obtain a high-purity trimethyl phosphite product.

[0029] This invention encompasses any substitutions, modifications, equivalent methods, and solutions made within the spirit and scope of this invention. To provide the public with a thorough understanding of this invention, specific details are described in detail in the following preferred embodiments; however, those skilled in the art will fully understand the invention even without these details. Furthermore, to avoid unnecessary misunderstanding of the essence of this invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0030] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A reaction device for continuous synthesis of trimethyl phosphite, comprising a raw material tank group (1), a composite reaction kettle (2), a solvent tank (3), a pre-cooler (4), a water washing kettle (5), an alkali liquid buffer tank (6), a layering system (7) and a rectification system (8), characterized in that, The raw material tank group (1) includes a methanol tank and a phosphorus trichloride tank. The raw material tank group (1) and the solvent tank (3) are connected to the composite reactor (2) through a pipe via a precooler (4). The composite reactor (2) is connected to the water washing tank (5) through a pipe. The alkaline buffer tank (6) is connected to the water washing tank (5) through a pipe via a precooler (4). The water washing tank (5) is connected to the distillation system (8) via a stratification system (7). The composite reactor (2) includes a tank body (21), a receiving hopper (211) is provided at the bottom of the tank body (21), and a discharge pipe (212) is provided at the bottom of the receiving hopper (211). The tank (21) is equipped with a coaxially rotating centrifugal disc (26) and a spray ring (27). The centrifugal disc (26) is used to receive phosphorus trichloride falling vertically and to use the centrifugal force of high-speed rotation to convert the droplet feed into an annular thin liquid film and throw it outward. The spray ring (27) is located below the centrifugal disc (26). The spray ring (27) is used to receive the phosphorus trichloride liquid film falling from above and spray the liquid out in the form of a fine jet under the action of centrifugal force.

2. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 1, characterized by, The tank (21) is rotatably connected to a drive shaft (25), and the top of the tank (21) is provided with a drive motor (24) for driving the drive shaft (25). The centrifugal disc (26) and the spray ring (27) are both fixed outside the drive shaft (25).

3. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 2, characterized by, The centrifugal disc (26) has a conical structure with a concave receiving area (261) in the middle. The conical surface of the centrifugal disc (26) is provided with a spiral guide groove (262) connected to the receiving area (261), and the outer edge is provided with an upward-extending anti-splash flange (263).

4. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 2, characterized in that, The spray ring (27) has a receiving groove (271) with an open top. The side of the spray ring (27) has multiple downward-sloping micro-holes (272), and the micro-holes (272) are connected to the receiving groove (271).

5. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 4, characterized in that, The opening of the spray ring (27) is provided with a flange (273), both sides of the inner wall of the receiving groove (271) are provided with concave stop portions (274), and the outer side of the spray ring (27) is provided with an inner groove portion (275).

6. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 3, characterized in that, The top of the tank (21) is symmetrically provided with a top feed pipe (213), the bottom end of which extends to the top of the receiving area (261) to transport phosphorus trichloride to the receiving area (261).

7. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 1, characterized in that, A reaction cavity is formed between the spray ring (27) and the inner wall of the tank (21). A tangential feed pipe (214) is symmetrically arranged on the outer side of the tank (21), and the feed inlet of the tangential feed pipe (214) is located in the reaction cavity.

8. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 1, characterized in that, A cleaning mechanism (28) is provided inside the tank (21) and between the centrifuge disc (26) and the spray ring (27). The cleaning mechanism (28) includes a fixing frame and a scraper installed on its outer side. The fixing frame is fixed on the drive shaft (25), and the scraper is located inside the reaction chamber.

9. The reaction apparatus for the continuous synthesis of trimethyl phosphite according to claim 1, characterized in that, A heat exchange circulation pipe (23) is provided on the outside of the tank (21). An insulation cover (22) is provided on the outside of the tank (21) and on the outside of the heat exchange circulation pipe (23). The inlet and outlet ends of the heat exchange circulation pipe (23) extend to the outside of the insulation cover (22).

10. A method for synthesizing trimethyl phosphite using a reaction apparatus as described in claim 1, characterized in that, Includes the following steps: S1. Start the drive motor (24) of the composite reactor (2) to make the centrifugal disc (26) and the spray ring (27) rotate. The mixture of methanol in the methanol tank and organic solvent and acid binder in the solvent tank (3) is cooled to a predetermined temperature by the precooler (4) and then combined. It is then pumped into the reaction chamber through the tangential feed pipe (214) to form a vortex flow field flowing downward. S2. After phosphorus trichloride is cooled by the precooler (4), it is pumped in through the top feed pipe (213) and falls vertically onto the high-speed rotating centrifugal disc (26), where it is centrifugally dispersed into an annular liquid film and transferred into the spray ring (27). S3. The phosphorus trichloride liquid film is centrifuged in the spray ring (27) and sprayed out in the form of a jet through the micropore (272) to mix and react with the methanol and solvent mixed vortex formed in step S1. S4. The reaction products are continuously discharged from the discharge pipe (212) into the water washing tank (5). At the same time, the alkaline solution in the alkaline solution buffer tank (6) is cooled by the precooler (4) and then pumped into the water washing tank (5) for neutralization and water washing. S5. Crude trimethyl phosphite is obtained in the upper layer through the layering system (7). After drying, the crude trimethyl phosphite is pumped into the distillation system (8) for distillation to obtain the product trimethyl phosphite.

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