An automated process for the production of 4,6-dichloro-5-methoxypyrimidine

Abstract

This invention discloses an automated production method for 4,6-dichloro-5-methoxypyrimidine, belonging to the field of chemical production technology. The method includes the following steps: mixing 4,6-dihydroxy-5-methoxypyrimidine, phosphorus oxychloride, and a magnetic solid deacidifying agent to form a solid-liquid suspension; continuously feeding the solid-liquid suspension into a continuous flow reactor and applying an alternating magnetic field within the reactor to carry out a chlorination reaction; performing online solid-liquid separation on the reaction solution to retain the magnetic solid deacidifying agent bound with hydrogen chloride, obtaining a clarified reaction solution; regenerating the magnetic solid deacidifying agent in situ; and performing solvent removal treatment on the clarified reaction solution to obtain 4,6-dichloro-5-methoxypyrimidine. This invention, by introducing a magnetic solid deacidifying agent, a continuous flow reaction driven by an alternating magnetic field, and a dual-station high-gradient magnetic separation in-situ regeneration technology, significantly improves product quality, yield, and the cyclic stability of the deacidifying agent.

Description

Technical Field

[0001] This invention relates to the field of chemical production technology, specifically to an automated production method for 4,6-dichloro-5-methoxypyrimidine. Background Technology

[0002] 4,6-Dichloro-5-methoxypyrimidine, also known as 5-methoxy-4,6-dichloropyrimidine, is an important intermediate in the synthesis of chlorinated pyrimidine organic compounds. It appears as a white to off-white crystalline powder, has a stable pyrimidine ring structure and good reactivity, and is widely used in the pharmaceutical and pesticide fields.

[0003] The mainstream preparation process of 4,6-dichloro-5-methoxypyrimidine uses 4,6-dihydroxy-5-methoxypyrimidine as raw material, phosphorus oxychloride as chlorinating agent, and N,N-dimethylaniline as deacidifying agent to produce it through a chlorination reaction, and has been achieved on a large scale.

[0004] However, traditional processes use homogeneous organic bases (such as N,N-dimethylaniline) as deacidifying agents. These bases coexist with phosphorus oxychloride in the liquid phase, which can easily undergo nucleophilic substitution to generate quaternary phosphonium salts or phosphoramides, leading to the failure of the deacidifying agent and the ineffective consumption of POCl3.

[0005] Based on this, the present invention designs an automated production method for 4,6-dichloro-5-methoxypyrimidine to solve the above problems. Summary of the Invention

[0006] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an automated production method for 4,6-dichloro-5-methoxypyrimidine.

[0007] To achieve the above objectives, the present invention provides the following technical solution: An automated method for producing 4,6-dichloro-5-methoxypyrimidine includes the following steps: 4,6-dihydroxy-5-methoxypyrimidine, phosphorus oxychloride and magnetic solid deacidifying agent are mixed to form a solid-liquid suspension; The solid-liquid suspension is continuously fed into a continuous flow reactor, and an alternating magnetic field is applied inside the reactor. The alternating magnetic field causes the magnetic solid deacidifying agent to oscillate or rotate in the fluid, thereby enhancing mixing. A reaction solution is obtained through a chlorination reaction. The reaction solution was subjected to online solid-liquid separation to retain the magnetic solid deacidifying agent that was bound with hydrogen chloride, resulting in a clear reaction solution. The retained magnetic solid deacidifying agent is regenerated in situ; The clarified reaction solution was subjected to solvent removal treatment to obtain 4,6-dichloro-5-methoxypyrimidine.

[0008] Furthermore, the magnetic solid deacidifying agent includes a magnetic core, an insulating transition shell covering the magnetic core, and a polymeric deacidifying functional layer covering the insulating transition shell; the polymeric deacidifying functional layer contains pyridine groups for binding hydrogen chloride.

[0009] Furthermore, the magnetic core is nano-iron oxide, the insulating transition shell is mesoporous silica, and the polymer deacidification functional layer is poly(4-vinylpyridine). Specifically, nano-sized iron oxide microspheres were prepared using a hydrothermal method. Then, a mesoporous silica layer was prepared on the surface of the nano-sized iron oxide microspheres using a sol-gel method. The microspheres were then dispersed in an ethanol / water mixed solvent (volume ratio 4:1), and 12% (by mass) of 4-vinylpyridine, 1.5% (by mass) of divinylbenzene (DVB), and 0.5% (by mass) of benzoyl peroxide (BPO) were added. The reaction was carried out under nitrogen protection and stirred at 80°C for 8 hours. After the reaction, the mixture was centrifuged, washed three times with ethanol, and dried under vacuum at 50°C for 8 hours to obtain a magnetic solid deacidifying agent.

[0010] The magnetic solid deacidifying agent comprises, by mass percentage: 10%-13% of the nano-iron oxide, 12%-18% of the mesoporous silica, and the balance of the poly-4-vinylpyridine.

[0011] In this invention, the magnetic solid deacidifying agent uses nano-iron oxide as the magnetic core, mesoporous silica as the insulating transition shell, and cross-linked poly(4-vinylpyridine) as the polymeric deacidifying functional layer. The pyridine groups in the cross-linked poly(4-vinylpyridine) network can undergo acid-base bonding with the hydrogen chloride generated during the chlorination reaction to form a pyridine salt structure, thereby reducing the concentration of free hydrogen chloride in the reaction system.

[0012] Because the poly(4-vinylpyridine) functional layer is a cross-linked polymer network, the pyridine groups are fixed within the polymer chain segments, which restricts their freedom of movement and effective reaction orientation. Simultaneously, phosphorus oxychloride requires a diffusion process to enter the polymer functional layer and react effectively with the pyridine groups, thus suppressing side reactions between phosphorus oxychloride and the pyridine groups. In contrast, the acid-base combination reaction between hydrogen chloride and the pyridine groups is more direct, and hydrogen chloride can diffuse into the polymer functional layer and combine with the pyridine groups. Therefore, the magnetic solid deacidifying agent is mainly used to capture the hydrogen chloride generated during the reaction.

[0013] Under the influence of an alternating magnetic field, the magnetic solid deacidifying agent undergoes micro-oscillations or orientation changes in the solid-liquid suspension system, enhancing local mixing and mass transfer, which is beneficial for the continuous execution of the chlorination reaction and hydrogen chloride capture process. After the reaction, the magnetic solid deacidifying agent bound to hydrogen chloride is retained online through a high-gradient magnetic separator and then reverse-washed with an alkaline alcohol solution, restoring the pyridinium salt structure to free pyridinium groups, thereby achieving in-situ regeneration and recycling of the deacidifying agent.

[0014] Furthermore, the continuous flow reactor is a slurry-type continuous flow reactor suitable for solid-liquid suspension systems, capable of conveying solid-liquid suspensions with a large solid content. An electromagnetic induction coil is provided on the outer wall of the continuous flow reactor, and the alternating magnetic field is applied by the electromagnetic induction coil. Furthermore, the magnetic field strength of the alternating magnetic field is 50-100 mT, and the frequency is 50-200 Hz. The reaction is carried out at a pressure of 0.2-0.5 MPa and a temperature of 95-105℃. The average residence time of the solid-liquid suspension in the continuous flow reactor is 40-60 min.

[0015] Furthermore, the online solid-liquid separation includes: passing the reaction liquid through a high-gradient magnetic separator, whereby the magnetic solid deacidifying agent is captured and retained by the magnetic field force, thereby achieving separation from the liquid; The in-situ regeneration includes: passing an alkaline alcohol solution into the retained magnetic solid deacidifying agent for reverse rinsing; after reverse rinsing, a second rinsing is performed with anhydrous methanol, followed by purging and drying with nitrogen before recycling; Equipped with dual-station high-gradient magnetic separators, one high-gradient magnetic separator performs online solid-liquid separation while the other high-gradient magnetic separator performs in-situ regeneration.

[0016] Furthermore, the alkaline alcohol solution is a sodium hydroxide methanol solution with a mass concentration of 2%-2.5%, and the reverse rinsing is carried out at room temperature for 4-8 minutes.

[0017] Furthermore, the mixing is performed using ultrasonic dispersion, with an ultrasonic frequency of 20-40kHz, a power of 700-850W, and a processing time of 15-30min. The molar ratio of 4,6-dihydroxy-5-methoxypyrimidine to phosphorus oxychloride is 1:5 to 1:7.

[0018] To better achieve the objectives of this invention, the present invention also provides a continuous production system for 4,6-dichloro-5-methoxypyrimidine, for implementing the aforementioned automated production method, comprising: A closed mixing vessel is used to mix 4,6-dihydroxy-5-methoxypyrimidine, phosphorus oxychloride and magnetic solid deacidifying agent to form a solid-liquid suspension. A continuous flow reactor, connected to the closed mixing vessel, has an electromagnetic induction coil wound around its outer wall and is configured to carry out a chlorination reaction under an alternating magnetic field; A diaphragm metering pump or screw feed pump with shear circulation is provided between the closed mixing vessel and the continuous flow reactor. An anchor or ribbon agitator is provided in the closed mixing vessel to maintain the slurry in suspension. A high-gradient magnetic separator, connected to the continuous flow reactor, is configured to retain the magnetic solid deacidifying agent bound with hydrogen chloride; The regenerated liquid supply unit is connected to the high gradient magnetic separator and is configured to pass an alkaline alcohol solution into the retained magnetic solid deacidifying agent for reverse rinsing. The drying unit is configured to dry the regenerated magnetic solid deacidifying agent; A continuous flash evaporator, connected to the high gradient magnetic separator, is configured to perform solvent removal treatment on the clarified reaction solution; And the pipelines and automated valves that connect the various devices.

[0019] To better achieve the objectives of this invention, the present invention also provides 4,6-dichloro-5-methoxypyrimidine prepared by the aforementioned automated production method.

[0020] Compared with the prior art, the beneficial effects of this invention are as follows: 1. This invention prepares a multilayer deacidifying agent with cross-linked poly(4-vinylpyridine) (P4VP) as the functional layer. The cross-linked polymer three-dimensional network forms steric hindrance and mass transfer restriction on the pyridine groups, which can inhibit the side reaction between the pyridine groups and phosphorus oxychloride, reduce the risk of traditional homogeneous organic bases easily generating quaternary phosphonium salts or phosphoramides and becoming ineffective, and improve the cycle stability of the deacidifying agent while reducing the ineffective consumption of POCl3.

[0021] 2. This invention uses a high-gradient magnetic separator to achieve online non-destructive retention of magnetic solid deacidifying agent, and introduces a low-concentration alkaline alcohol solution for room temperature reverse rinsing and regeneration, thereby achieving efficient in-situ recovery of the deacidifying agent. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] Example 1: An automated production method for 4,6-dichloro-5-methoxypyrimidine, comprising the following steps: I. Preparation of Magnetic Solid Deacidifying Agent Nano-sized iron oxide microspheres were prepared using a hydrothermal method. A mesoporous silica layer was then formed on the surface of the nano-iron oxide microspheres using a sol-gel method. The microspheres were then dispersed in an ethanol / water mixture (volume ratio 4:1), and 12% (by mass) of 4-vinylpyridine, 1.5% (by mass) of divinylbenzene (DVB), and 0.5% (by mass) of benzoyl peroxide (BPO) were added. The reaction was carried out under nitrogen protection at 80°C with stirring for 8 hours. After the reaction, the mixture was centrifuged, washed three times with ethanol, and dried under vacuum at 50°C for 8 hours to obtain a magnetic solid deacidifying agent with a D50 of 20-80 μm. By mass percentage, the magnetic solid deacidifying agent contained 10% nano-iron oxide, 18% mesoporous silica, and the balance poly-4-vinylpyridine.

[0024] 2. Mix 1.0 mol of 4,6-dihydroxy-5-methoxypyrimidine, 7 mol of phosphorus oxychloride and 340 g of magnetic solid deacidifying agent, and disperse by ultrasonication at a frequency of 20 kHz and a power of 850 W for 15 min to form a solid-liquid suspension.

[0025] 3. The solid-liquid suspension is continuously fed into a continuous flow reactor. An alternating magnetic field of 50mT and 200Hz is applied by an electromagnetic induction coil on the outer wall of the continuous flow reactor. The alternating magnetic field causes the magnetic solid deacidifying agent to oscillate or rotate in the fluid, thereby enhancing mixing. The reaction solution is obtained through a chlorination reaction. The chlorination reaction was carried out at a pressure of 0.2 MPa and a reaction temperature of 105 °C. The average residence time of the solid-liquid suspension in the continuous flow reactor was 40 min.

[0026] Fourth, the reaction liquid is passed through a high-gradient magnetic separator, where the magnetic solid deacidifying agent is captured and retained by the magnetic field force, resulting in a clear reaction liquid. 5. Pass a 2% sodium hydroxide methanol solution into the retained magnetic solid deacidifying agent and perform a reverse rinse at room temperature for 8 minutes; after the reverse rinse, perform a second rinse with anhydrous methanol, and then purge and dry with nitrogen before recycling. Equipped with dual-station high-gradient magnetic separators, one high-gradient magnetic separator performs online solid-liquid separation while the other high-gradient magnetic separator performs in-situ regeneration.

[0027] 6. The clarified reaction solution was subjected to solvent removal treatment to obtain 4,6-dichloro-5-methoxypyrimidine.

[0028] Example 2: An automated production method for 4,6-dichloro-5-methoxypyrimidine, comprising the following steps: I. Preparation of Magnetic Solid Deacidifying Agent Nano-sized iron oxide microspheres were prepared using a hydrothermal method. A mesoporous silica layer was then formed on the surface of the nano-iron oxide microspheres using a sol-gel method. The microspheres were then dispersed in an ethanol / water mixture (volume ratio 4:1), and 12% (by mass) of 4-vinylpyridine, 1.5% (by mass) of divinylbenzene (DVB), and 0.5% (by mass) of benzoyl peroxide (BPO) were added. The reaction was carried out under nitrogen protection at 80°C with stirring for 8 hours. After the reaction, the mixture was centrifuged, washed three times with ethanol, and dried under vacuum at 50°C for 8 hours to obtain a magnetic solid deacidifying agent with a D50 of 20-80 μm. By mass percentage, the magnetic solid deacidifying agent contained 13% nano-iron oxide, 12% mesoporous silica, and the balance poly-4-vinylpyridine.

[0029] 2. Mix 1.0 mol of 4,6-dihydroxy-5-methoxypyrimidine, 5.0 mol of phosphorus oxychloride and 350 g of magnetic solid deacidifying agent, and disperse by ultrasonication at a frequency of 40 kHz and a power of 700 W for 30 min to form a solid-liquid suspension.

[0030] 3. The solid-liquid suspension is continuously fed into a continuous flow reactor. An alternating magnetic field of 100mT and 50Hz is applied by an electromagnetic induction coil on the outer wall of the continuous flow reactor. The alternating magnetic field causes the magnetic solid deacidifying agent to oscillate or rotate in the fluid, thereby enhancing mixing. The reaction solution is obtained through a chlorination reaction. The chlorination reaction was carried out at a pressure of 0.5 MPa and a reaction temperature of 95°C. The average residence time of the solid-liquid suspension in the continuous flow reactor was 60 min.

[0031] Fourth, the reaction liquid is passed through a high-gradient magnetic separator, where the magnetic solid deacidifying agent is captured and retained by the magnetic field force, resulting in a clear reaction liquid. 5. Pass a 2.5% sodium hydroxide methanol solution into the retained magnetic solid deacidifying agent and perform a reverse rinse at room temperature for 4 minutes; after the reverse rinse, perform a second rinse with anhydrous methanol, and then purge and dry with nitrogen before recycling. Equipped with dual-station high-gradient magnetic separators, one high-gradient magnetic separator performs online solid-liquid separation while the other high-gradient magnetic separator performs in-situ regeneration.

[0032] 6. The clarified reaction solution was subjected to solvent removal treatment to obtain 4,6-dichloro-5-methoxypyrimidine.

[0033] Example 3: An automated production method for 4,6-dichloro-5-methoxypyrimidine, comprising the following steps: I. Preparation of Magnetic Solid Deacidifying Agent Nano-sized iron oxide microspheres were prepared using a hydrothermal method. A mesoporous silica layer was then formed on the surface of the nano-iron oxide microspheres using a sol-gel method. The microspheres were then dispersed in an ethanol / water mixture (volume ratio 4:1), and 12% (by mass) of 4-vinylpyridine, 1.5% (by mass) of divinylbenzene (DVB), and 0.5% (by mass) of benzoyl peroxide (BPO) were added. The reaction was carried out under nitrogen protection at 80°C with stirring for 8 hours. After the reaction, the mixture was centrifuged, washed three times with ethanol, and dried under vacuum at 50°C for 8 hours to obtain a magnetic solid deacidifying agent with a D50 of 20-80 μm. By mass percentage, the magnetic solid deacidifying agent contained: 12% nano-iron oxide, 15% mesoporous silica, and the balance poly-4-vinylpyridine.

[0034] 2. Mix 1.0 mol of 4,6-dihydroxy-5-methoxypyrimidine, 6.0 mol of phosphorus oxychloride and 360 g of magnetic solid deacidifying agent, and disperse by ultrasonication at a frequency of 30 kHz and a power of 750 W for 20 min to form a solid-liquid suspension.

[0035] 3. The solid-liquid suspension is continuously fed into a continuous flow reactor. An alternating magnetic field of 80mT and 100Hz is applied by an electromagnetic induction coil on the outer wall of the continuous flow reactor. The alternating magnetic field causes the magnetic solid deacidifying agent to oscillate or rotate in the fluid, thereby enhancing mixing. The reaction solution is obtained through a chlorination reaction. The chlorination reaction was carried out at a pressure of 0.3 MPa and a reaction temperature of 98°C. The average residence time of the solid-liquid suspension in the continuous flow reactor was 50 min.

[0036] Fourth, the reaction liquid is passed through a high-gradient magnetic separator, where the magnetic solid deacidifying agent is captured and retained by the magnetic field force, resulting in a clear reaction liquid. 5. Pass a 2.2% sodium hydroxide methanol solution into the retained magnetic solid deacidifying agent and perform a reverse rinse at room temperature for 5 minutes; after the reverse rinse, perform a second rinse with anhydrous methanol, and then purge and dry with nitrogen before recycling. Equipped with dual-station high-gradient magnetic separators, one high-gradient magnetic separator performs online solid-liquid separation while the other high-gradient magnetic separator performs in-situ regeneration.

[0037] 6. The clarified reaction solution was subjected to solvent removal treatment to obtain 4,6-dichloro-5-methoxypyrimidine.

[0038] Example 4: This example provides a continuous production system for 4,6-dichloro-5-methoxypyrimidine to implement the aforementioned automated production method, including: A closed mixing vessel is used to mix 4,6-dihydroxy-5-methoxypyrimidine, phosphorus oxychloride and magnetic solid deacidifying agent to form a solid-liquid suspension. A continuous flow reactor, connected to the closed mixing vessel, has an electromagnetic induction coil wound around its outer wall and is configured to carry out a chlorination reaction under an alternating magnetic field; A diaphragm metering pump or screw feed pump with shear circulation is provided between the closed mixing vessel and the continuous flow reactor. An anchor or ribbon agitator is provided in the closed mixing vessel to maintain the slurry in suspension. A high-gradient magnetic separator, connected to the continuous flow reactor, is configured to retain the magnetic solid deacidifying agent bound with hydrogen chloride; The regenerated liquid supply unit is connected to the high gradient magnetic separator and is configured to pass an alkaline alcohol solution into the retained magnetic solid deacidifying agent for reverse rinsing. The drying unit is configured to dry the regenerated magnetic solid deacidifying agent; A continuous flash evaporator, connected to the high gradient magnetic separator, is configured to perform solvent removal treatment on the clarified reaction solution; And the pipelines and automated valves that connect the various devices.

[0039] Comparative Example 1: Using a conventional preparation process: 50 mL of dichloromethane was added to 9.3 g of disodium 4,6-dihydroxy-5-methoxypyrimidine, and the mixture was stirred at 20 °C for 1 h. The temperature was lowered to 0 °C, and 40 mL of phosphorus oxychloride and 8 mL of N,N-dimethylaniline were slowly added dropwise, controlling the temperature to be below 10 °C during the addition. After the addition was complete, the mixture was refluxed for 1 h. The dichloromethane was distilled off, and the residue was poured into 150 mL of ice water, stirred for 1 h, filtered, and recrystallized from ethanol to obtain 4,6-dichloro-5-methoxypyrimidine.

[0040] The product test data for Examples 1-3 are as follows: purity ≥ 99%, yield ≥ 90%, and deacidifying agent cycle times ≥ 10 times.

[0041] The test data for Comparative Example 1 were: purity 98.0%, yield 79%, and the deacidifying agent (N,N-dimethylaniline) was not recyclable.

[0042] The automated production method for 4,6-dichloro-5-methoxypyrimidine of this invention, by introducing a magnetic solid deacidifying agent, a continuous flow reaction driven by an alternating magnetic field, and a dual-station high-gradient magnetic separation in-situ regeneration technology, significantly outperforms traditional homogeneous methods in key indicators such as product quality (purity ≥99%), yield (≥90%), deacidifying agent cycle stability (≥10 times), and production efficiency (continuous flow replacing batch). It possesses outstanding technical advantages and practical value.

[0043] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An automated production method for 4,6-dichloro-5-methoxypyrimidine, characterized in that, Includes the following steps: 4,6-dihydroxy-5-methoxypyrimidine, phosphorus oxychloride and magnetic solid deacidifying agent are mixed to form a solid-liquid suspension; The solid-liquid suspension is continuously fed into a continuous flow reactor, and an alternating magnetic field is applied inside the reactor to carry out a chlorination reaction, thereby obtaining a reaction solution. The reaction solution was subjected to online solid-liquid separation to retain the magnetic solid deacidifying agent that was bound with hydrogen chloride, resulting in a clear reaction solution. The retained magnetic solid deacidifying agent is regenerated in situ; The clarified reaction solution was subjected to solvent removal treatment to obtain 4,6-dichloro-5-methoxypyrimidine.

2. The automated production method according to claim 1, characterized in that, The magnetic solid deacidifying agent includes a magnetic core, an insulating transition shell covering the magnetic core, and a polymeric deacidifying functional layer covering the insulating transition shell; the polymeric deacidifying functional layer contains pyridine groups for binding hydrogen chloride.

3. The automated production method according to claim 2, characterized in that, The magnetic core is nano-iron oxide, the insulating transition shell is mesoporous silica, and the polymer deacidification functional layer is poly(4-vinylpyridine). The magnetic solid deacidifying agent comprises, by mass percentage: 10%-13% of the nano-iron oxide, 12%-18% of the mesoporous silica, and the balance of the poly-4-vinylpyridine.

4. The automated production method according to claim 1, characterized in that, The outer wall of the continuous flow reactor is equipped with an electromagnetic induction coil, and the alternating magnetic field is applied by the electromagnetic induction coil.

5. The automated production method according to claim 4, characterized in that, The magnetic field strength of the alternating magnetic field is 50-100mT, and the frequency is 50-200Hz. The chlorination reaction is carried out at a pressure of 0.2-0.5 MPa and a reaction temperature of 95-105℃. The average residence time of the solid-liquid suspension in the continuous flow reactor is 40-60 min.

6. The automated production method according to claim 1, characterized in that, The online solid-liquid separation includes: passing the reaction liquid through a high-gradient magnetic separator, where the magnetic solid deacidifying agent is captured and retained by the magnetic field force, thereby achieving separation from the liquid; The in-situ regeneration includes: passing an alkaline alcohol solution into the retained magnetic solid deacidifying agent for reverse rinsing; after reverse rinsing, a second rinsing is performed with anhydrous methanol, followed by purging and drying with nitrogen before recycling; Equipped with dual-station high-gradient magnetic separators, one high-gradient magnetic separator performs online solid-liquid separation while the other high-gradient magnetic separator performs in-situ regeneration.

7. The automated production method according to claim 6, characterized in that, The alkaline alcohol solution is a sodium hydroxide methanol solution with a mass concentration of 2%-2.5%. The reverse rinsing is carried out at room temperature and the rinsing time is 4-8 minutes.

8. The automated production method according to claim 1, characterized in that, The mixing is performed using ultrasonic dispersion, with an ultrasonic frequency of 20-40kHz, a power of 700-850W, and a processing time of 15-30min. The molar ratio of 4,6-dihydroxy-5-methoxypyrimidine to phosphorus oxychloride is 1:5 to 1:

7.

9. A continuous production system for 4,6-dichloro-5-methoxypyrimidine, for implementing the automated production method according to any one of claims 1 to 8, characterized in that, include: A closed mixing vessel is used to mix 4,6-dihydroxy-5-methoxypyrimidine, phosphorus oxychloride and magnetic solid deacidifying agent to form a solid-liquid suspension. A continuous flow reactor, connected to the closed mixing vessel, has an electromagnetic induction coil wound around its outer wall and is configured to carry out a chlorination reaction under an alternating magnetic field; A high-gradient magnetic separator, connected to the continuous flow reactor, is configured to retain the magnetic solid deacidifying agent bound with hydrogen chloride; The regenerated liquid supply unit is connected to the high gradient magnetic separator and is configured to pass an alkaline alcohol solution into the retained magnetic solid deacidifying agent for reverse rinsing. The drying unit is configured to dry the regenerated magnetic solid deacidifying agent; A continuous flash evaporator, connected to the high gradient magnetic separator, is configured to perform solvent removal treatment on the clarified reaction solution; And the pipelines and automated valves that connect the various devices.

10. 4,6-Dichloro-5-methoxypyrimidine produced by the automated production method according to any one of claims 1 to 8.