Efficient preparation method of 2-chloroacrylonitrile intermediate 2, 3-dichloropropionitrile

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to an efficient preparation method of a 2-chloroacrylonitrile intermediate 2, 3-dichloropropionitrile, which comprises the following steps: mixing acrylonitrile with a solvent, and adding an initiator to obtain a reaction solution; mixing chlorine with nitrogen to obtain mixed gas; the reaction liquid and the mixed gas are mixed and contacted in the first-stage plate type micro-reaction module, and the reaction retention time is controlled to prepare a first-stage mixture; the first-stage mixture sequentially enters a second-stage plate-type micro-reaction module, a third-stage plate-type micro-reaction module, a fourth-stage plate-type micro-reaction module and a fifth-stage plate-type micro-reaction module, and a mixed product is prepared; and carrying out gas-liquid separation, water washing and drying on the mixed product, and carrying out rectification separation to obtain a target product. By optimizing reaction conditions and process parameters, the mass transfer efficiency and the mixing effect can be enhanced, the method has the advantages of high reaction efficiency, good product quality and the like, and a new technical choice is provided for industrial production.

Description

Technical Field

[0001] This invention belongs to the field of chemical synthesis technology, specifically relating to an efficient method for preparing 2,3-dichloropropionitrile, an intermediate of 2-chloroacrylonitrile. Background Technology

[0002] 2,3-Dichloropropionitrile, as an industrial-grade organic synthesis intermediate, is widely used in pesticides, pharmaceuticals, new chemical materials and other fields.

[0003] Chinese invention patent CN112047897A discloses a method for preparing 3-aminoisoxazole, which involves the preparation of 2,3-dichloropropionitrile: acrylonitrile, N,N-dimethylformamide, and pyridine are added to a reaction vessel, the temperature is lowered to 5-15°C, chlorine gas is introduced into the reaction vessel, and the reaction temperature is maintained at 10-20°C; after the chlorine gas is introduced, the temperature is controlled at 15-25°C and stirred for 5 hours; excess chlorine gas is blown out until the reaction solution is slightly yellow or colorless and transparent, thus obtaining 2,3-dichloropropionitrile.

[0004] It is evident that existing synthesis methods mainly employ batch reactors, which suffer from problems such as long reaction times, low production efficiency, and low purity. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides an efficient method for preparing 2,3-dichloropropionitrile, an intermediate of 2-chloroacrylonitrile, thereby achieving efficient and high-purity synthesis of 2,3-dichloropropionitrile.

[0006] To solve the above-mentioned technical problems, the present invention provides an efficient method for preparing 2,3-dichloropropionitrile, an intermediate of 2-chloroacrylonitrile, comprising the following steps: S1. Prepare a five-stage series plate microreactor module, purge the plate microreactor module with nitrogen, control the reaction temperature at 55-70℃, and control the reaction pressure at 0.1-0.5MPa; S2. Mix acrylonitrile and solvent at a volume ratio of 1:2 to 5, and add 0.5 to 0.8 wt% of initiator to obtain a reaction solution; S3. After drying, chlorine is mixed with nitrogen at a volume ratio of 0.5 to 1:1 to obtain a mixed gas. S4. The reaction liquid and mixed gas are mixed and contacted in the first-stage plate micro-reaction module. The material reaction residence time is controlled to be 60-120s to obtain a first-stage mixture. S5. The primary mixture enters the second-stage plate micro-reaction module, and the material reaction residence time is controlled to be 60-120s to obtain the secondary mixture. S6. The secondary mixture enters the third-stage plate micro-reaction module, and the material reaction residence time is controlled to be 60-120s to obtain the tertiary mixture. S7. The three-stage mixture enters the fourth-stage plate micro-reaction module, and the material reaction residence time is controlled to be 45-90s to obtain the four-stage mixture. S8. The fourth-stage mixture enters the fifth-stage plate micro-reaction module, and the material reaction residence time is controlled to be 45-90s to obtain the mixed product. S9. After gas-liquid separation, the liquid product is washed with water, dried, and then separated by distillation to obtain the target product 2,3-dichloropropionitrile.

[0007] Preferably, the reaction pressure of the first-stage plate microreactor module, the second-stage plate microreactor module, and the third-stage plate microreactor module is controlled at 0.3 to 0.5 MPa, and the reaction temperature is 60 to 70 °C.

[0008] Preferably, the reaction pressure of the fourth-stage plate microreactor module and the fifth-stage plate microreactor module is controlled at 0.1 to 0.3 MPa, and the reaction temperature is 55 to 65°C.

[0009] Preferably, the initiator is azobisisobutyronitrile.

[0010] Preferably, the solvent is N,N-dimethylacetamide.

[0011] Preferably, the molar ratio of chlorine gas to acrylonitrile introduced into the first-stage plate microreactor module is 0.8 to 1.05:1.

[0012] Preferably, the specific surface area of ​​the plate-type microreactor module is 5000–15000 m². 2 / m 3 .

[0013] Preferably, the reaction cavity of the plate-type microreactor module has a heart-shaped structure.

[0014] Preferably, the plate-type microreactor module is made of photocurable cyclic olefin copolymer resin.

[0015] Preferably, the plate-type microreactor module includes the following preparation steps: 1) Use 3D printing or injection molding processes to prepare reaction core molds and heat exchange core molds using paraffin wax as raw material; 2) After aligning the reaction core mold and the heat exchange core mold, suspend them in the mold cavity, inject photocurable cyclic olefin copolymer resin, and after vacuum degassing treatment, cure under ultraviolet light to form a composite blank; 3) Cut and polish the cured composite blank to produce the module outline that meets the design requirements, and process the material inlet, material outlet, medium inlet and medium outlet; 4) Place the processed composite blank in a constant temperature hot water at 80℃, and introduce compressed gas into the material inlet and the medium inlet. The core mold melts and is discharged with the airflow, ultimately forming the reaction chamber and the heat exchange chamber. 5) Pump 80°C hot water containing silica abrasive particles into the material inlet and medium inlet to polish the inner walls of the reaction chamber and heat exchange chamber, reduce the surface roughness of the chamber, and obtain the plate-type micro-reaction module after cleaning and drying.

[0016] After adopting the above technical solution, the beneficial effects of the present invention are: 1. This application is based on a plate-type microreactor module. By optimizing reaction conditions and process parameters, it can enhance mass transfer efficiency and mixing effect, and has the advantages of high reaction efficiency, good product quality and safe and reliable process. It provides a new technical option for the industrial production of 2,3-dichloropropionitrile. 2. A reaction and heat exchange core mold is prepared using paraffin wax, and a cyclic olefin resin is cured by ultraviolet light to form a composite blank. The core mold is then melted and discharged. Compared with traditional Hastelloy, this method achieves low-cost and large-scale production of plate-type micro-reaction modules. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is the chromatogram of Example 1. Detailed Implementation

[0019] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely to provide a better understanding of the present invention by illustrating examples of the invention.

[0020] Example 1 This embodiment provides an efficient method for preparing 2,3-dichloropropionitrile, an intermediate of 2-chloroacrylonitrile. The specific preparation steps and technical details are as follows.

[0021] S1, Pretreatment of the reaction system A five-stage series plate microreactor module was configured, with each stage having a liquid holding capacity of 100 mL. The reaction system was continuously purged with nitrogen at a flow rate of 100 mL / min. Purging was stopped after confirming that the oxygen content in the system was ≤0.1% using an oxygen analyzer, thus creating an inert environment.

[0022] The reaction chamber of the plate-type microreactor module adopts a heart-shaped chamber structure. Its periodic concave and convex units generate eddies through curvature abrupt changes, which makes the fluid form strong mixing in the radial direction, enhances mass transfer efficiency, and is especially suitable for rapid gas-liquid reactions.

[0023] S2, Preparation of reactants 100 mL of acrylonitrile was mixed with 200 mL of N,N-dimethylacetamide (DMAC). Based on the total mass of the mixture, 0.5 wt% (approximately 1.65 g) of azobisisobutyronitrile (AIBN) was added as an initiator, and the mixture was stirred until completely dissolved to obtain a reaction solution. Chlorine gas, after drying, was mixed with nitrogen gas at a volume ratio of 0.5:1 in a static mixer to prepare a mixed gas with a chlorine gas fraction of 33.3%.

[0024] N,N-Dimethylacetamide can dissolve acrylonitrile and initiators, which is beneficial to the reaction, maintains the stability of the reaction system, and improves the reaction efficiency.

[0025] S3, Free radical reaction The reaction liquid and the mixed gas have a specific surface area of ​​15000 m². 2 / m 3 The mixture was mixed and contacted in the first-stage plate microreactor module. The molar ratio of chlorine gas to acrylonitrile was 0.8:1. The residence time of the material in the module was controlled at 60s, the reaction temperature was controlled at 70℃, and the reaction pressure was controlled at 0.3MPa to obtain the first-stage mixture.

[0026] The primary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The second-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 70℃, and the reaction pressure to 0.3MPa, thus producing a secondary mixture.

[0027] The secondary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The third-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 70℃, and the reaction pressure to 0.3MPa, thus producing a three-stage mixture.

[0028] The three-stage mixture sequentially enters a specific surface area of ​​5000 m². 2 / m 3The fourth-stage plate microreactor module controls the material reaction residence time to 45s, the reaction temperature to 65℃, and the reaction pressure to 0.1MPa, thus producing a four-stage mixture.

[0029] The four-stage mixture sequentially enters a specific surface area of ​​5000 m². 2 / m 3 The fifth-stage plate microreactor module controls the material reaction residence time to 45s, the reaction temperature to 65℃, and the reaction pressure to 0.1MPa, thus obtaining a mixed product.

[0030] The free radical addition reaction of acrylonitrile and chlorine initiated by AIBN was efficiently synthesized by precisely matching the free radical generation rate, substrate contact efficiency and reaction selectivity through the structural design of a plate microreactor module (enhanced mass transfer) and the control of staged process parameters (temperature, pressure and residence time).

[0031] The first three stages constitute the deep reaction phase, where high pressure increases the solubility of chlorine gas, enhances free radical initiation and chain growth, ensures deep conversion of raw materials, guides the reaction towards the target product, and reduces the formation of polymerization byproducts. The latter two stages constitute the product stabilization reaction phase, suppressing polychlorination side reactions and providing a gentle finish.

[0032] S4, Post-processing After the mixed product was separated by depressurization, the collected liquid product was washed with water, dried, and then separated by distillation to obtain 2,3-dichloropropionitrile with a purity of 99.5%.

[0033] Example 2 Based on Example 1, the difference in Example 2 is as follows: The reaction liquid and the mixed gas have a specific surface area of ​​15000 m². 2 / m 3 The mixture was mixed and contacted in the first-stage plate microreactor module. The molar ratio of chlorine gas to acrylonitrile was 0.8:1. The residence time of the material in the module was controlled to be 120s. The reaction temperature was controlled at 60℃ and the reaction pressure was controlled at 0.5MPa to obtain the first-stage mixture. The primary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The second-stage plate-type microreactor module controls the material reaction residence time to 120s, the reaction temperature to 60℃, and the reaction pressure to 0.5MPa, thus obtaining a secondary mixture; The secondary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3The third-stage plate-type microreactor module controls the material reaction residence time to 120s, the reaction temperature to 60℃, and the reaction pressure to 0.5MPa, thus producing a three-stage mixture. The three-stage mixture sequentially enters a specific surface area of ​​5000 m². 2 / m 3 The fourth-stage plate-type microreactor module controls the material reaction residence time to 90s, the reaction temperature to 55℃, and the reaction pressure to 0.3MPa, thus producing a four-stage mixture. The four-stage mixture sequentially enters a specific surface area of ​​5000 m². 2 / m 3 The fifth-stage plate-type microreactor module controls the material reaction residence time to 90s, the reaction temperature to 55℃, and the reaction pressure to 0.3MPa to obtain a mixed product. After the mixed product was separated by depressurization, the collected liquid product was washed with water, dried, and then separated by distillation to obtain 2,3-dichloropropionitrile with a purity of 99.8%.

[0034] Example 3 The difference between Example 1 and Example 3 is that: The reaction liquid and the mixed gas have a specific surface area of ​​15000 m². 2 / m 3 The mixture was mixed and contacted in the first-stage plate microreactor module. The molar ratio of chlorine gas to acrylonitrile was 0.8:1. The residence time of the material in the module was controlled at 80s, the reaction temperature was controlled at 65℃, and the reaction pressure was controlled at 0.4MPa to obtain the first-stage mixture. The primary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The second-stage plate-type microreactor module controls the material reaction residence time to 80s, the reaction temperature to 65℃, and the reaction pressure to 0.4MPa, thus producing a secondary mixture; The secondary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The third-stage plate-type microreactor module controls the material reaction residence time to 80s, the reaction temperature to 65℃, and the reaction pressure to 0.4MPa, thus producing a three-stage mixture. The three-stage mixture sequentially enters a specific surface area of ​​5000 m². 2 / m 3 The fourth-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 60℃, and the reaction pressure to 0.2MPa, thus producing a four-stage mixture. The four-stage mixture sequentially enters a specific surface area of ​​5000 m². 2 / m 3The fifth-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 60℃, and the reaction pressure to 0.2MPa to obtain a mixed product. After the mixed product was separated by depressurization, the collected liquid product was washed with water, dried, and then separated by distillation to obtain 2,3-dichloropropionitrile with a purity of 99.7%.

[0035] Example 4 Based on Example 1, this example provides an efficient method for preparing the 2-chloroacrylonitrile intermediate 2,3-dichloropropionitrile. The specific preparation steps and technical details are as follows: S1. Configure a five-stage series plate microreactor module group, with a liquid holding capacity of 100 mL for each stage module, and use nitrogen gas to continuously purge the reaction system at a flow rate of 100 mL / min. S2. Mix 100 mL of acrylonitrile with 300 mL of N,N-dimethylacetamide. Based on the total mass of the mixture, add 0.65 wt% (about 3 g) of azobisisobutyronitrile as an initiator and stir until completely dissolved to obtain the reaction solution. S3. After drying, chlorine gas is mixed with nitrogen gas in a static mixer at a volume ratio of 0.8:1 to prepare a mixed gas with a chlorine gas fraction of 44.4%. S4, the reaction liquid and the mixed gas have a specific surface area of ​​15000 m². 2 / m 3 The mixture was mixed and contacted in the first-stage plate microreactor module. The molar ratio of chlorine gas to acrylonitrile was 0.8:1. The residence time of the material in the module was controlled at 60s, the reaction temperature was controlled at 70℃, and the reaction pressure was controlled at 0.3MPa to obtain the first-stage mixture. S5, the primary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The second-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 70℃, and the reaction pressure to 0.3MPa, thus producing a secondary mixture; S6, the secondary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The third-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 70℃, and the reaction pressure to 0.3MPa, thus producing a three-stage mixture. S7, the three-stage mixture sequentially enters a specific surface area of ​​5000 m² 2 / m 3 The fourth-stage plate-type microreactor module controls the material reaction residence time to 45s, the reaction temperature to 65℃, and the reaction pressure to 0.1MPa, thus producing a four-stage mixture. S8, the fourth-stage mixture sequentially enters a specific surface area of ​​5000 m² 2 / m 3 The fifth-stage plate microreactor module controls the material reaction residence time to 45s, the reaction temperature to 65℃, and the reaction pressure to 0.1MPa to obtain a mixed product. S9. After gas-liquid separation, the liquid product is washed with water, dried, and then separated by distillation to obtain 2,3-dichloropropionitrile with a purity of 99.6%.

[0036] Example 5 Based on Example 1, this example provides an efficient method for preparing the 2-chloroacrylonitrile intermediate 2,3-dichloropropionitrile. The specific preparation steps and technical details are as follows: S1. Configure a five-stage series plate microreactor module group, with a liquid holding capacity of 100 mL for each stage module, and use nitrogen gas to continuously purge the reaction system at a flow rate of 100 mL / min. S2. Mix 100 mL of acrylonitrile with 500 mL of N,N-dimethylacetamide. Based on the total mass of the mixture, add 0.8 wt% (approximately 4.6 g) of azobisisobutyronitrile as an initiator and stir until completely dissolved to obtain the reaction solution. S3. After drying, chlorine is mixed with nitrogen in a static mixer at a volume ratio of 1:1 to prepare a mixed gas with a chlorine gas fraction of 50%. S4, the reaction liquid and the mixed gas have a specific surface area of ​​15000 m². 2 / m 3 The mixture was mixed and contacted in the first-stage plate microreactor module. The molar ratio of chlorine gas to acrylonitrile was 1.05:1. The residence time of the material in the module was controlled at 60s, the reaction temperature was controlled at 70℃, and the reaction pressure was controlled at 0.3MPa to obtain the first-stage mixture. S5, the primary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The second-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 70℃, and the reaction pressure to 0.3MPa, thus producing a secondary mixture; S6, the secondary mixture sequentially enters a specific surface area of ​​10000 m² 2 / m 3 The third-stage plate-type microreactor module controls the material reaction residence time to 60s, the reaction temperature to 70℃, and the reaction pressure to 0.3MPa, thus producing a three-stage mixture. S7, the three-stage mixture sequentially enters a specific surface area of ​​5000 m² 2 / m 3The fourth-stage plate-type microreactor module controls the material reaction residence time to 45s, the reaction temperature to 65℃, and the reaction pressure to 0.1MPa, thus producing a four-stage mixture. S8, the fourth-stage mixture sequentially enters a specific surface area of ​​5000 m² 2 / m 3 The fifth-stage plate microreactor module controls the material reaction residence time to 45s, the reaction temperature to 65℃, and the reaction pressure to 0.1MPa to obtain a mixed product. S9. After gas-liquid separation, the liquid product is washed with water, dried, and then separated by distillation to obtain 2,3-dichloropropionitrile with a purity of 99.3%.

[0037] Example 2 optimized the chlorine quantity, residence time, and low-temperature, high-pressure conditions to achieve a perfect balance between conversion rate and selectivity.

[0038] The plate-type microreactor module used in the above embodiments is made of photocurable cyclic olefin copolymer resin (COC), and its preparation steps include: The COC resin was preheated and softened at 100°C. 15wt% (based on the COC resin mass) of isoborneol acrylate was added as an active diluent, and the mixture was stirred at 1000rpm for 10min to reduce the viscosity of the system. The temperature was then lowered to 40°C, and 0.1wt% of photoinitiator Irgacure819 and 0.2wt% leveling agent BYK-UV3510 were added. The mixture was stirred for another 20min, and then vacuum degassed (-0.09MPa, 15min) to remove the air bubbles introduced by stirring, resulting in a transparent light-cured COC resin solution.

[0039] Conventional industrial-grade microchannel reactors are mostly constructed using metals such as Hastelloy and stainless steel, and their manufacturing processes rely on precision machining and wire cutting technologies, resulting in high processing accuracy. The geometric reconstruction of the reaction chambers requires the redesign and fabrication of an entire mold set, leading to a long modification cycle and modification costs approaching those of manufacturing entirely new reactors. Therefore, this embodiment also provides a method for preparing a plate-type microreactor module, with the specific steps as follows: 1) Use 3D printing or injection molding processes to prepare reaction core molds and heat exchange core molds using paraffin wax as raw material; 2) After aligning the reaction core mold and the heat exchange core mold, suspend them in the mold cavity, inject light-cured COC resin liquid, degas at -0.09MPa for 15min, and then cure under ultraviolet light to form a composite blank with an embedded core mold; 3) Cut and polish the cured composite blank to produce the module outline that meets the design requirements, and process the material inlet, material outlet, medium inlet and medium outlet to ensure the integrity of the subsequent fluid passage. 4) Place the processed composite blank in a constant temperature hot water at 80℃, and introduce compressed gas into the material inlet and the medium inlet. The core mold melts and is discharged with the airflow, ultimately forming the reaction chamber and the heat exchange chamber. 5) Pump 80°C hot water containing silica abrasive particles into the material inlet and medium inlet to polish the inner walls of the reaction chamber and heat exchange chamber, reduce the surface roughness of the chamber, and obtain the plate-type micro-reaction module after cleaning and drying.

[0040] Compared to traditional Hastelloy, the cured cyclic olefin copolymer resin material enables low-cost and large-scale production of plate-type microreactor modules.

[0041] The embodiments described above are not exhaustive and do not limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the above description. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to effectively utilize the invention and its modifications. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A highly efficient method for preparing 2,3-dichloropropionitrile, an intermediate of 2-chloroacrylonitrile, characterized in that, Includes the following steps: S1. Prepare a five-stage series plate microreactor module, purge the plate microreactor module with nitrogen, control the reaction temperature at 55-70℃, and control the reaction pressure at 0.1-0.5MPa; S2. Mix acrylonitrile and solvent at a volume ratio of 1:2 to 5, and add 0.5 to 0.8 wt% of initiator to obtain a reaction solution; S3. After drying, chlorine is mixed with nitrogen at a volume ratio of 0.5 to 1:1 to obtain a mixed gas. S4. The reaction liquid and mixed gas are mixed and contacted in the first-stage plate micro-reaction module. The material reaction residence time is controlled to be 60-120s to obtain a first-stage mixture. S5. The primary mixture enters the second-stage plate micro-reaction module, and the material reaction residence time is controlled to be 60-120s to obtain the secondary mixture. S6. The secondary mixture enters the third-stage plate micro-reaction module, and the material reaction residence time is controlled to be 60-120s to obtain the tertiary mixture. S7. The three-stage mixture enters the fourth-stage plate micro-reaction module, and the material reaction residence time is controlled to be 45-90s to obtain the four-stage mixture. S8. The fourth-stage mixture enters the fifth-stage plate micro-reaction module, and the material reaction residence time is controlled to be 45-90s to obtain the mixed product. S9. After gas-liquid separation, the liquid product is washed with water, dried, and then separated by distillation to obtain the target product 2,3-dichloropropionitrile.

2. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 1, is characterized in that: The reaction pressure of the first-stage plate microreactor module, the second-stage plate microreactor module, and the third-stage plate microreactor module is controlled at 0.3 to 0.5 MPa, and the reaction temperature is 60 to 70℃.

3. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 2, is characterized in that: The reaction pressure of the fourth-stage plate microreactor module and the fifth-stage plate microreactor module is controlled at 0.1-0.3 MPa, and the reaction temperature is 55-65℃.

4. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 1, is characterized in that: The initiator is azobisisobutyronitrile.

5. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 1, is characterized in that: The solvent is N,N-dimethylacetamide.

6. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 1, is characterized in that: The molar ratio of chlorine gas to acrylonitrile introduced into the first-stage plate microreactor module is 0.8 to 1.05:

1.

7. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 1, is characterized in that: The specific surface area of ​​the plate-type microreaction module is 5000–15000 m². 2 / m 3 .

8. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 7, characterized in that: The reaction cavity of the plate-type microreactor module has a heart-shaped structure.

9. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 8, characterized in that: The plate-type microreactor module is made of photocurable cyclic olefin copolymer resin.

10. The efficient preparation method of 2,3-dichloropropionitrile, the intermediate of 2-chloroacrylonitrile according to claim 9, characterized in that: The plate-type microreactor module includes the following preparation steps: 1) Use 3D printing or injection molding processes to prepare reaction core molds and heat exchange core molds using paraffin wax as raw material; 2) After aligning the reaction core mold and the heat exchange core mold, suspend them in the mold cavity, inject photocurable cyclic olefin copolymer resin, and after vacuum degassing treatment, cure under ultraviolet light to form a composite blank; 3) Cut and polish the cured composite blank to produce the module outline that meets the design requirements, and process the material inlet, material outlet, medium inlet and medium outlet. 4) Place the processed composite blank in a constant temperature hot water at 80℃, and introduce compressed gas into the material inlet and the medium inlet. The core mold melts and is discharged with the airflow, ultimately forming the reaction chamber and the heat exchange chamber. 5) Pump 80°C hot water containing silica abrasive particles into the material inlet and medium inlet to polish the inner walls of the reaction chamber and heat exchange chamber, reduce the surface roughness of the chamber, and obtain the plate-type micro-reaction module after cleaning and drying.

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