Preparation method and device of N, N '-carbonyldiimidazole

Abstract

The invention relates to the technical field of heterocyclic compound synthesis, and particularly discloses a preparation method and device of N, N '-carbonyldiimidazole, and the preparation device of N, N'-carbonyldiimidazole comprises: a mixed flow tank, which is internally provided with a continuous flow mixing unit and a continuous flow preparation unit; the continuous flow reaction unit is communicated with the outlet end of the mixed flow tank and is used for carrying out continuous flow reaction; the heating unit is connected with the continuous flow reaction unit and is used for heating the continuous flow reaction; the discharging unit is communicated with the outlet end of the continuous flow reaction unit and is used for discharging reaction products. Through the continuous flow synthesis process, the uniformity and continuity of the synthesis process can be effectively improved, so that the synthesis efficiency and the product quality of the N, N '-carbonyldiimidazole are improved, the yield of the N, N'-carbonyldiimidazole is improved, the high purity of the product is ensured, and meanwhile, the generation of byproducts is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of heterocyclic compound synthesis, and more specifically, it relates to a preparation method and device for N,N'-carbonyldiimidazole. Background Art

[0002] N,N'-carbonyldiimidazole (CDI) is an imidazole derivative with two imidazole rings, which can form stable coordination compounds with various metal ions. Therefore, it has potential application value in materials science, pharmaceutical chemistry, and catalyst development. In addition, it can also be used as an intermediate in organic synthesis for synthesizing other complex organic compounds;

[0003] Currently, phosgene is mainly used as a carbonylation reagent to synthesize N,N'-carbonyldiimidazole. Since phosgene is a highly toxic chemical, this synthesis method has serious safety and environmental problems; there is also a more environmentally friendly method using carbonate ester to synthesize N,N'-carbonyldiimidazole. This process is more environmentally friendly and easier to operate, but the product conversion rate and yield are still not ideal, and there is room for further optimization. Summary of the Invention

[0004] In order to overcome the above technical problems, the present invention provides a preparation method and device for N,N'-carbonyldiimidazole.

[0005] The object of the present invention can be achieved by the following technical solutions:

[0006] A preparation method for N,N'-carbonyldiimidazole, comprising the following steps:

[0007] S1. Raw material preparation: Prepare imidazole, diphenyl carbonate, and sodium methoxide, remove the impurities in the raw materials, and set aside for use;

[0008] S2. Solution preparation: Dissolve imidazole in anhydrous xylene to prepare an imidazole solution; dissolve diphenyl carbonate in anhydrous xylene to prepare a supersaturated solution of diphenyl carbonate;

[0009] S3. Continuous flow mixing: Mix the imidazole solution and the supersaturated solution of diphenyl carbonate in a molar ratio of 1:1.2 to form a mixed solution, and add sodium methoxide to the mixed solution. The dosage of sodium methoxide is 1-2 mol% of the imidazole solution;

[0010] S4. Continuous flow reaction: Heat the mixed solution to carry out a continuous flow reaction to obtain a semi-finished product; the reaction temperature is 130-140 °C, and the pressure is 2-3 bar;

[0011] S5. Product discharge: Discharge the semi-finished product;

[0012] S6. Separation and purification: The semi-finished product is subjected to solid-liquid separation by a centrifuge to collect solid CDI; the collected solid CDI is purified by solvent crystallization to obtain the finished product CDI.

[0013] The present invention also discloses a preparation device for N,N'-carbonyldiimidazole, which is applied to the above-mentioned preparation method of N,N'-carbonyldiimidazole, and includes:

[0014] A base;

[0015] A mixed-flow tank, which is installed on the base. The inlet end of the mixed-flow tank is respectively equipped with a first feed pipe and a second feed pipe, and a continuous-flow mixing unit and a continuous-flow preparation unit are arranged in the mixed-flow tank;

[0016] A continuous-flow reaction unit, which is communicated with the outlet end of the mixed-flow tank and is used for carrying out a continuous-flow reaction;

[0017] A heating unit, which is connected to the continuous-flow reaction unit and is used for heating the continuous-flow reaction;

[0018] A discharging unit, which is communicated with the outlet end of the continuous-flow reaction unit and is used for discharging the reaction product.

[0019] As a further solution of the present invention: The continuous-flow mixing unit includes a spherical cover communicated with the first feed pipe and a conical cover covering the periphery of the spherical cover. A plurality of through holes are opened on the upper hemispherical shell of the spherical cover, and the bottom of the conical cover is open;

[0020] An annular cavity is arranged on the inner wall of the conical cover. A communicating pipe is connected between the second feed pipe and the annular cavity, and an annular overflow groove is opened on one side of the annular cavity facing the spherical cover.

[0021] As a further solution of the present invention: The continuous-flow preparation unit includes a plurality of fixed partitions circumferentially arranged at the bottom of the mixed-flow tank and an arc-shaped sliding rod slidably penetrating through each fixed partition. A notch is opened on the fixed partition, and a plurality of flow-pushing plates adapted to the notch are arranged on the arc-shaped sliding rod;

[0022] A rotating shaft is rotatably installed on the mixed-flow tank, a driving motor for driving the rotating shaft is installed on the outer wall of the mixed-flow tank, a sector gear is sleeved on the rotating shaft, a rack meshing with the sector gear is arranged at one end of the arc-shaped sliding rod, and a spring is sleeved at the other end of the arc-shaped sliding rod.

[0023] As a further solution of the present invention: A catalyst feeding unit is further arranged on the mixed-flow tank. The catalyst feeding unit includes a storage bin installed on the top of the mixed-flow tank, and a plurality of feeding pipes extending into the mixed-flow tank are communicated at the lower end of the storage bin, and the lengths of the feeding pipes are different.

[0024] As a further solution of the present invention: The continuous flow reaction unit includes a reaction cylinder and a first piston disk movably embedded in the reaction cylinder. A first piston rod is installed at the upper end of the first piston disk and movably penetrates through the reaction cylinder.

[0025] As a further solution of the present invention: The heating unit includes a heating table connected to the bottom of the reaction cylinder. A T-shaped channel is provided in the heating table. The two ends of the T-shaped channel are respectively communicated with the mixing tank and the discharging unit, and the upper end of the T-shaped channel is communicated with the reaction cylinder;

[0026] A flow channel switching disk is rotatably installed at the three-channel intersection of the T-shaped channel. A flow-through groove is provided on one side of the flow channel switching disk. A switching motor for driving the flow channel switching disk is installed on the heating table.

[0027] As a further solution of the present invention: A discharge pipe is connected to the outlet end of the mixing tank. A connecting unit is provided between the discharge pipe and the T-shaped channel of the heating table. The connecting unit includes a connecting pipe communicated with the discharge pipe and the T-shaped channel. A rotating rod is rotatably installed in the connecting pipe, and a circular valve plate adapted to the connecting pipe is provided on the rotating rod.

[0028] As a further solution of the present invention: The discharging unit includes a discharge pipe. One side of the discharge pipe is communicated with the T-shaped channel, and the bottom of the discharge pipe is open. A second piston rod is provided in the discharge pipe;

[0029] A plug adapted to the bottom opening of the discharge pipe is provided at the lower end of the second piston rod, and a second piston disk is provided at the upper end of the second piston rod;

[0030] A first air pipe and a second air pipe are sequentially arranged from top to bottom at the upper end of the discharge pipe. The first air pipe is located above the second piston disk, and the second air pipe is located below the second piston disk.

[0031] As a further solution of the present invention: An end cover is detachably installed at one end of the discharge pipe away from the heating unit. A fixing rod is horizontally installed on the end cover, and a spiral piece adapted to the inner wall of the discharge pipe is provided on the fixing rod. A spiral flow channel is formed inside the spiral piece.

[0032] Advantages of the present invention:

[0033] Through the above continuous flow synthesis process, the uniformity and continuity of the synthesis process can be effectively improved, thereby improving the synthesis efficiency and product quality of N,N'-carbonyldiimidazole, increasing the yield of N,N'-carbonyldiimidazole, ensuring the high purity of the product, and reducing the generation of by-products at the same time. Description of the drawings

[0034] The present invention will be further described below with reference to the accompanying drawings.

[0035] Figure 1 Process flow diagram of a preparation method of N,N'-carbonyldiimidazole according to the present invention;

[0036] Figure 2 Stereogram of a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0037] Figure 3 Cross-sectional view of a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0038] Figure 4 is Figure 3 Enlarged view at position A in;

[0039] Figure 5 Cross-sectional view of a mixing tank in a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0040] Figure 6 Partial view of a mixing tank in a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0041] Figure 7 is Figure 6 Enlarged view at position B in;

[0042] Figure 8 Cross-sectional view of a heating unit, a connecting unit, a reaction unit and a discharging unit in a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0043] Figure 9 Schematic diagram of the state during the liquid extraction process in a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0044] Figure 10 Schematic diagram of the state during the reaction process in a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0045] Figure 11 Schematic diagram of the state during the liquid discharging process in a preparation device of N,N'-carbonyldiimidazole according to the present invention;

[0046] Figure 12 Schematic diagram of the structure of a discharging unit in a preparation device of N,N'-carbonyldiimidazole according to the present invention.

[0047] In the figure:

[0048] 100, base;

[0049] 200, Mixed-flow tank; 201, Maintenance door; 210, First feed pipe; 220, Second feed pipe; 230, Continuous-flow mixing unit; 231, Conical cover; 232, Spherical cover; 233, Through hole; 234, Connecting pipe; 235, Annular cavity; 236, Annular overflow groove; 240, Continuous-flow preparation unit; 241, Fixed partition; 242, Notch; 243, Arc-shaped slide bar; 244, Flow-pushing plate; 245, Spring; 246, Rotating shaft; 247, Sector gear; 248, Rack; 250, Drain pipe; 251, End cover; 252, Fixed rod; 253, Spiral fin; 254, Spiral flow channel; 260, Catalyst feeding unit; 261, Storage bin; 262, Feeding pipe;

[0050] 300, Heating unit; 310, Heating table; 320, Flow-channel switching disk; 321, Flow-through groove; 330, Switching motor;

[0051] 400, Connecting unit; 410, Connecting pipe; 420, Rotating rod; 430, Circular valve plate;

[0052] 500, Continuous-flow reaction unit; 510, Reaction cylinder; 520, First piston disk; 530, First piston rod;

[0053] 600, Discharging unit; 610, Discharge pipe; 620, Second piston rod; 630, Blockage; 640, Second piston disk; 650, First air pipe; 660, Second air pipe. Detailed implementation manners

[0054] Now, the subject matter described herein will be discussed with reference to exemplary embodiments. It should be understood that discussing these embodiments is only to enable those skilled in the art to better understand and thus implement the subject matter described herein. Without departing from the scope of protection of the content of this specification, changes can be made to the functions and arrangements of the elements discussed. Each example can omit, substitute, or add various processes or components as needed. Additionally, the features described relative to some examples can also be combined in other examples.

[0055] Please refer to Figure 1 , the present invention discloses a preparation method of N,N'-carbonyldiimidazole, including the following steps:

[0056] S1, Raw material preparation: Prepare imidazole, diphenyl carbonate, and sodium methoxide, remove impurities from the raw materials, and set aside for use;

[0057] S2, Solution preparation: Dissolve imidazole in anhydrous xylene to prepare an imidazole solution; dissolve diphenyl carbonate in anhydrous xylene to prepare a supersaturated solution of diphenyl carbonate;

[0058] S3. Continuous flow mixing: Mix an imidazole solution and a supersaturated solution of diphenyl carbonate in a molar ratio of 1:1.2 to form a mixed solution, and add sodium methoxide to the mixed solution. The dosage of sodium methoxide is 1-2 mol% of the imidazole solution;

[0059] S4. Continuous flow reaction: Heat the mixed solution to carry out a continuous flow reaction to obtain a semi-finished product; the reaction temperature is 130-140 °C and the pressure is 2-3 bar;

[0060] S5. Product discharge: Discharge the semi-finished product;

[0061] S6. Separation and purification: Carry out solid-liquid separation on the semi-finished product by a centrifuge to collect solid CDI; purify the collected solid CDI by solvent crystallization to obtain the finished CDI.

[0062] Through the above continuous flow synthesis process, the uniformity and continuity of the synthesis process can be effectively improved, thereby improving the synthesis efficiency and product quality of N,N'-carbonyldiimidazole, increasing the yield of N,N'-carbonyldiimidazole, ensuring the high purity of the product, and reducing the generation of by-products.

[0063] In one embodiment, please refer to Figure 2 and Figure 3 , for the above preparation method of N,N'-carbonyldiimidazole, the present invention also discloses a preparation device for N,N'-carbonyldiimidazole, which is applied to the above preparation method of N,N'-carbonyldiimidazole, and includes a base 100, a mixing tank 200, a heating unit 300, a continuous flow reaction unit 500 and a discharge unit 600; the mixing tank 200 is installed on the base 100, and a first feed pipe 210 and a second feed pipe 220 are respectively installed at the inlet end of the mixing tank 200. A continuous flow mixing unit 230 and a continuous flow preparation unit 240 are arranged in the mixing tank 200; the continuous flow reaction unit 500 is communicated with the outlet end of the mixing tank 200 for carrying out a continuous flow reaction; the heating unit 300 is connected to the continuous flow reaction unit 500 for heating the continuous flow reaction; the discharge unit 600 is communicated with the outlet end of the continuous flow reaction unit 500 for discharging the reaction product;

[0064] Specifically, an imidazole solution is injected into the mixing tank 200 through the first feed pipe 210, and a supersaturated solution of diphenyl carbonate is injected into the mixing tank 200 through the second feed pipe 220. The imidazole solution and the supersaturated solution of diphenyl carbonate are filled in a molar ratio of 1:1.2. The continuous flow mixing unit 230 is used to mix the imidazole solution and the supersaturated solution of diphenyl carbonate to form a mixed solution, and then the continuous flow preparation unit 240 is used to prepare the mixed solution to form a reaction solution. Then, the reaction solution is periodically introduced into the continuous flow reaction unit 500, and the heating unit 300 is used to heat the continuous flow reaction unit 500 to make the reaction solution reach the reaction temperature for continuous flow reaction to produce a reaction product. Finally, the reaction product is discharged through the discharge unit 600.

[0065] In one embodiment, please refer to Figure 2 , a maintenance door 201 is provided on one side of the mixing tank 200. The maintenance door 201 remains in a normally closed state and is only opened when maintenance is required inside the mixing tank 200.

[0066] Please refer to Figure 5 、 Figure 6 and Figure 7 , the continuous flow mixing unit 230 includes a spherical cover 232 communicated with the first feed pipe 210 and a conical cover 231 covering the periphery of the spherical cover 232. A plurality of through holes 233 are formed on the upper hemispherical shell of the spherical cover 232, and the bottom of the conical cover 231 is open. An annular cavity 235 is provided on the inner wall of the conical cover 231. A communicating pipe 234 is connected between the second feed pipe 220 and the annular cavity 235. An annular overflow groove 236 is formed on the side of the annular cavity 235 facing the spherical cover 232;

[0067] Specifically, the imidazole solution enters the spherical cover 232 through the first feed pipe 210 and is ejected outward through the circumferentially distributed through holes 233. Then, the ejected imidazole solution falls onto the inner conical surface of the conical cover 231 in a parabolic shape under the action of gravity and slides down along the inner conical surface. The supersaturated solution of diphenyl carbonate enters the annular cavity 235 through the second feed pipe 220 and the communicating pipe 234 and is ejected obliquely upward from the annular overflow groove 236. The circumferentially ejected supersaturated solution of diphenyl carbonate contacts the imidazole solution sliding down along the inner conical surface, thereby realizing the full mixing of the imidazole solution and the supersaturated solution of diphenyl carbonate and improving the mixing effect of the imidazole solution and the supersaturated solution of diphenyl carbonate.

[0068] Further, please refer to Figure 5, the continuous flow preparation unit 240 includes a plurality of fixed partitions 241 circumferentially arranged at the bottom of the mixing tank 200 and arc-shaped sliding rods 243 slidably penetrating through each fixed partition 241. The fixed partition 241 is provided with a notch 242, and a plurality of flow pushing plates 244 adapted to the notch 242 are arranged on the arc-shaped sliding rod 243;

[0069] A rotating shaft 246 is rotatably installed on the mixing tank 200, and a driving motor (not shown in the figure) for driving the rotating shaft 246 is installed on the outer wall of the mixing tank 200. A sector gear 247 is sleeved on the rotating shaft 246. One end of the arc-shaped sliding rod 243 is provided with a rack 248 meshing with the sector gear 247, and a spring 245 is sleeved on the other end of the arc-shaped sliding rod 243;

[0070] Specifically, the mixed solution after mixing treatment falls from the opening below the conical cover 231 to the bottom of the mixing tank 200. By driving the rotating shaft 246 to continuously rotate through the driving motor, the sector gear 247 is driven to rotate counterclockwise. When the toothed part on the sector gear 247 meshes with the rack 248, the arc-shaped sliding rod 243 is driven to slide circumferentially in the mixing tank 200, so that the flow pushing plate 244 and the fixed partition 241 are relatively displaced. At the same time, the spring 245 is compressed, and the mixed solution between adjacent fixed partitions 241 can be pushed to one side; Subsequently, the toothed part on the sector gear 247 disengages from the rack 248, and the arc-shaped sliding rod 243 slides reversely and resets under the elastic force of the spring 245, driving the flow pushing plate 244 to be relatively displaced with the fixed partition 241 in the reverse direction again, so as to push the mixed solution between adjacent fixed partitions 241 to the other side; In this way, the mixed solution between each fixed partition 241 impacts each other, and the repetitive pushing of the mixed solution can be realized until the preparation of the reaction solution is completed.

[0071] In addition, please refer to Figure 5 , a catalyst feeding unit 260 is further provided on the mixing tank 200. The catalyst feeding unit 260 includes a storage bin 261 installed on the top of the mixing tank 200. The lower end of the storage bin 261 is communicated with a plurality of feeding pipes 262 extending into the mixing tank 200, and the lengths of the feeding pipes 262 are different;

[0072] During the preparation of the reaction solution, the catalyst sodium methoxide filled in the storage bin 261 penetrates into the mixed solution through the feeding pipes 262 at the lower end, and the lengths of the different feeding pipes 262 are also different, so that different layers of the solution can be covered, enabling the catalyst to be fully integrated with the mixed solution, which is beneficial to the rapid progress of the subsequent continuous flow reaction and improves the reaction rate.

[0073] In another embodiment, please refer to Figure 8, the continuous flow reaction unit 500 includes a reaction cylinder 510 and a first piston disk 520 movably embedded in the reaction cylinder 510. A first piston rod 530 that movably penetrates the reaction cylinder 510 is installed at the upper end of the first piston disk 520, and the first piston rod 530 can be pneumatically driven;

[0074] Specifically, when the reaction solution is prepared, drive the first piston rod 530 to move upward, driving the first piston disk 520 to rise synchronously, so that a negative pressure is generated in the area below the first piston disk 520 in the reaction cylinder 510, and then the reaction solution in the mixing tank 200 is sucked into the reaction cylinder 510. The reaction solution in the reaction cylinder 510 is heated by the heating unit 300, and a continuous flow reaction can be carried out.

[0075] Further, please refer to Figure 8 , the heating unit 300 includes a heating table 310 connected to the bottom of the reaction cylinder 510. A T-shaped channel is opened in the heating table 310. The two ends of the T-shaped channel are respectively communicated with the mixing tank 200 and the discharging unit 600, and the upper end of the T-shaped channel is communicated with the reaction cylinder 510; A flow channel switching disk 320 is rotatably installed at the three-channel intersection of the T-shaped channel. A flow through groove 321 is opened on one side of the flow channel switching disk 320, and a switching motor 330 for driving the flow channel switching disk 320 is installed on the heating table 310;

[0076] Specifically, please refer to Figure 9 , liquid pumping process: Drive the flow channel switching disk 320 to rotate through the switching motor 330, so that the flow through groove 321 communicates with one end of the T-shaped channel facing the mixing tank 200 and one end of the T-shaped channel facing the reaction cylinder 510. When the first piston disk 520 moves upward, the reaction solution in the mixing tank 200 can be pumped into the reaction cylinder 510;

[0077] Please refer to Figure 10 , reaction process: Drive the flow channel switching disk 320 to rotate through the switching motor 330, so that the flow through groove 321 rotates to directly below. At this time, the flow channel switching disk 320 closes all three ports of the T-shaped channel. The first piston disk 520 moves downward to pressurize the inside of the reaction cylinder 510 until the air pressure in the reaction cylinder 510 reaches the reaction conditions, and then heat the reaction solution in the reaction cylinder 510 to the reaction temperature through the heating table 310, and a continuous flow reaction can be carried out;

[0078] Please refer to Figure 11 , liquid discharging process: Drive the flow channel switching disk 320 to rotate through the switching motor 330, so that the flow through groove 321 communicates with one end of the T-shaped channel facing the discharging unit 600 and one end of the T-shaped channel facing the reaction cylinder 510. When the first piston disk 520 moves downward, the reaction solution in the mixing tank 200 can be squeezed into the discharging unit 600.

[0079] Further, please refer to Figure 8 A drain pipe 250 is connected to the outlet end of the mixed flow tank 200. A connection unit 400 is arranged between the drain pipe 250 and the T-shaped channel of the heating table 310. The connection unit 400 includes a connecting pipe 410 communicating with the drain pipe 250 and the T-shaped channel. A rotating rod 420 is rotatably installed in the connecting pipe 410. A circular valve plate 430 adapted to the connecting pipe 410 is arranged on the rotating rod 420;

[0080] Please refer to Figure 9 During the liquid pumping process, the rotating rod 420 drives the circular valve plate 430 to rotate, so that the axis of the circular valve plate 430 is perpendicular to the axis of the connecting pipe 410. At this time, the channel of the connecting pipe 410 is opened, and the reaction solution in the mixed flow tank 200 can enter the reaction cylinder 510;

[0081] Please refer to Figure 10 and Figure 11 During the reaction process and the liquid discharging process, the rotating rod 420 drives the circular valve plate 430 to rotate, so that the axis of the circular valve plate 430 coincides with the axis of the connecting pipe 410. At this time, the channel of the connecting pipe 410 is closed, thereby preventing the reaction solution from flowing crosswise.

[0082] In addition, please refer to Figure 12 The discharging unit 600 includes a discharging pipe 610. One side of the discharging pipe 610 communicates with the T-shaped channel. The bottom of the discharging pipe 610 is open. A second piston rod 620 is arranged in the discharging pipe 610; A plug 630 adapted to the bottom opening of the discharging pipe 610 is arranged at the lower end of the second piston rod 620. A second piston disc 640 is arranged at the upper end of the second piston rod 620; A first air pipe 650 and a second air pipe 660 are sequentially arranged at the upper end of the discharging pipe 610 from top to bottom. The first air pipe 650 is located above the second piston disc 640, and the second air pipe 660 is located below the second piston disc 640;

[0083] Please refer to Figure 9 and Figure 10 During the liquid pumping and reaction processes, air is blown into the discharging pipe 610 through the first air pipe 650 to push the second piston disc 640 downward, thereby driving the plug 630 at the lower end of the second piston rod 620 to block the lower opening of the discharging pipe 610 and prevent the reaction solution from flowing crosswise;

[0084] Please refer to Figure 11 During the liquid discharging process, air is blown into the discharging pipe 610 through the second air pipe 660 to push the second piston disc 640 upward, thereby driving the plug 630 at the lower end of the second piston rod 620 to separate from the lower opening of the discharging pipe 610 and open the lower opening of the discharging pipe 610 for facilitating the discharge of the reaction product.

[0085] Please refer toFigure 3 and Figure 4 One end of the drain pipe 250 away from the heating unit 300 is detachably installed with an end cover 251. A fixing rod 252 is horizontally installed on the end cover 251. A spiral fin 253 that fits the inner wall of the drain pipe 250 is arranged on the fixing rod 252. A spiral flow channel 254 is formed inside the spiral fin 253;

[0086] The prepared reaction solution flows into the drain pipe 250. Subsequently, the reaction solution is spirally fed under the guiding action of the spiral flow channel 254, and the reaction solution can be further mixed, effectively improving the mixing effect of the reactants.

[0087] The specific implementation manners of this embodiment have been described above, but this embodiment is not limited to the above specific implementation manners. The above specific implementation manners are only illustrative and not restrictive. Under the inspiration of this embodiment, those of ordinary skill in the art can also make many forms, all of which fall within the protection scope of this embodiment.

Claims

1. A preparation method of N,N'-carbonyldiimidazole, characterized in that, It includes the following steps: S1. Raw material preparation: Prepare imidazole, diphenyl carbonate and sodium methoxide, remove the impurities of the raw materials, and reserve them for use; S2. Solution preparation: Dissolve imidazole in anhydrous xylene to prepare an imidazole solution; dissolve diphenyl carbonate in anhydrous xylene to prepare a supersaturated solution of diphenyl carbonate; S3. Continuous flow mixing: Mix the imidazole solution and the supersaturated solution of diphenyl carbonate in a molar ratio of 1:1.2 to form a mixed solution, and add sodium methoxide to the mixed solution. The dosage of sodium methoxide is 1-2 mol% of the imidazole solution; S4. Continuous flow reaction: Heat the mixed solution to carry out a continuous flow reaction to obtain a semi-finished product; the reaction temperature is 130-140 °C and the pressure is 2-3 bar; S5. Product discharge: Discharge the semi-finished product; S6. Separation and purification: Perform solid-liquid separation on the semi-finished product by a centrifuge to collect solid CDI; purify the collected solid CDI by solvent crystallization to obtain the finished CDI.

2. An apparatus for preparing N,N'-carbonyldiimidazole, which is applied to the method for preparing N,N'-carbonyldiimidazole according to claim 1, characterized in that, It includes: Base (100); Mixed flow tank (200), which is installed on the base (100). The inlet end of the mixed flow tank (200) is respectively installed with a first feed pipe (210) and a second feed pipe (220). A continuous flow mixing unit (230) and a continuous flow preparation unit (240) are arranged in the mixed flow tank (200); Continuous flow reaction unit (500), which is communicated with the outlet end of the mixed flow tank (200) and is used for carrying out continuous flow reaction; Heating unit (300), which is connected to the continuous flow reaction unit (500) and is used for heating the continuous flow reaction; Discharge unit (600), which is communicated with the outlet end of the continuous flow reaction unit (500) and is used for discharging the reaction product.

3. The preparation device of N,N'-carbonyldiimidazole according to claim 2, characterized in that, The continuous flow mixing unit (230) includes a spherical cover (232) communicated with the first feed pipe (210) and a conical cover (231) covering the periphery of the spherical cover (232). A plurality of through holes (233) are opened on the upper hemispherical shell of the spherical cover (232), and the bottom of the conical cover (231) is open; An annular cavity (235) is arranged on the inner wall of the conical cover (231). A communication pipe (234) is connected between the second feed pipe (220) and the annular cavity (235), and an annular overflow groove (236) is opened on the side of the annular cavity (235) facing the spherical cover (232).

4. The preparation device of N, N'-carbonyldiimidazole according to claim 3, characterized in that, The continuous flow preparation unit (240) includes a plurality of fixed partitions (241) circumferentially arranged at the bottom of the mixed flow tank (200) and an arc-shaped sliding rod (243) sliding through each fixed partition (241). A notch (242) is opened on the fixed partition (241), and a plurality of flow pushing plates (244) adapted to the notch (242) are arranged on the arc-shaped sliding rod (243); A rotating shaft (246) is rotatably installed on the mixed-flow tank (200), and a driving motor for driving the rotating shaft (246) is installed on the outer wall of the mixed-flow tank (200). A sector gear (247) is sleeved on the rotating shaft (246). One end of the arc-shaped slide bar (243) is provided with a rack (248) meshing with the sector gear (247), and a spring (245) is sleeved on the other end of the arc-shaped slide bar (243).

5. The preparation device of N,N'-carbonyldiimidazole according to claim 2, characterized in that, A catalyst feeding unit (260) is further provided on the mixed-flow tank (200). The catalyst feeding unit (260) includes a storage bin (261) installed on the top of the mixed-flow tank (200). The lower end of the storage bin (261) is communicated with a plurality of feeding pipes (262) extending into the mixed-flow tank (200), and the lengths of the feeding pipes (262) are different.

6. The preparation device of N,N'-carbonyldiimidazole according to claim 2, characterized in that, The continuous flow reaction unit (500) includes a reaction cylinder (510) and a first piston disk (520) movably embedded in the reaction cylinder (510). A first piston rod (530) movably penetrating through the reaction cylinder (510) is installed at the upper end of the first piston disk (520).

7. The preparation device of N,N'-carbonyldiimidazole according to claim 6, characterized in that, The heating unit (300) includes a heating table (310) connected to the bottom of the reaction cylinder (510). A T-shaped channel is formed in the heating table (310). The two ends of the T-shaped channel are respectively communicated with the mixed-flow tank (200) and the discharging unit (600), and the upper end of the T-shaped channel is communicated with the reaction cylinder (510). A flow channel switching disk (320) is rotatably installed at the three-channel intersection of the T-shaped channel. A flow through groove (321) is formed on one side of the flow channel switching disk (320). A switching motor (330) for driving the flow channel switching disk (320) is installed on the heating table (310).

8. The preparation device of N, N'-carbonyldiimidazole according to claim 7, characterized in that, A drain pipe (250) is connected to the outlet end of the mixed-flow tank (200). A connecting unit (400) is arranged between the drain pipe (250) and the T-shaped channel of the heating table (310). The connecting unit (400) includes a connecting pipe (410) communicated with the drain pipe (250) and the T-shaped channel. A rotating rod (420) is rotatably installed in the connecting pipe (410), and a circular valve plate (430) adapted to the connecting pipe (410) is arranged on the rotating rod (420).

9. The preparation device of N, N'-carbonyldiimidazole according to claim 7, characterized in that, The discharging unit (600) includes a discharge pipe (610). One side of the discharge pipe (610) is communicated with the T-shaped channel, and the bottom of the discharge pipe (610) is open. A second piston rod (620) is arranged in the discharge pipe (610). A plug (630) adapted to the bottom opening of the discharge pipe (610) is arranged at the lower end of the second piston rod (620), and a second piston disk (640) is arranged at the upper end of the second piston rod (620). A first air pipe (650) and a second air pipe (660) are sequentially arranged from top to bottom at the upper end of the discharge pipe (610). The first air pipe (650) is located above the second piston disk (640), and the second air pipe (660) is located below the second piston disk (640).

10. The preparation apparatus of N, N'-carbonyldiimidazole according to claim 8, characterized in that, One end of the drainage pipe (250) far from the heating unit (300) is detachably installed with an end cover (251). A fixing rod (252) is horizontally installed on the end cover (251). A spiral fin (253) that fits the inner wall of the drainage pipe (250) is arranged on the fixing rod (252). A spiral flow channel (254) is formed inside the spiral fin (253).

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