One-pot electro-catalysis continuous circulating device for organic synthesis

Abstract

The invention relates to a one-pot electro-catalysis continuous circulating device for organic synthesis, which comprises an electrolytic bath, a filter, a liquid storage device and an electrolysis unit, the electrolysis unit is arranged in the electrolytic bath, the electrolysis unit is immersed in electrolyte, a plurality of anodes are arranged in the electrolysis unit, and cathodes are arranged on the side surface of the electrolysis unit; the filter and the liquid storage device are located outside the electrolytic bath, an inlet of the filter is connected with the electrolytic bath through a first pipeline, and an outlet of the filter is connected with a liquid inlet of the liquid storage device through a second pipeline, so that materials in the electrolytic bath are filtered by the filter, solid products are left in the filter, and filtered liquid enters the liquid storage device; a liquid outlet of the liquid storage device is connected with the electrolytic bath through a third pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalytic devices, and in particular relates to a one-pot electrocatalytic continuous circulation device for organic synthesis. Background Art

[0002] Electrochemical oxidation has the advantages of simple operation and green environmental protection. Electrochemical methods avoid the use of stoichiometric oxidants and reductants and instead use inert, environmentally friendly electron donors and acceptors. When electrochemical methods are applied to organic synthesis, anodic oxidation of organic compounds can be achieved in the presence of protic solvents as electron acceptors (i.e., oxidants), releasing hydrogen as a byproduct at the cathode. Therefore, electrochemistry has the potential to improve the sustainability of synthetic processes.

[0003] In recent years, with the application of electrochemical reactions, people have begun to pay attention to the use of electrochemical methods for large-scale experiments, and flow-type electrolysis systems have begun to become a common tool on a laboratory scale. Flow-type electrolysis systems include circulation systems and single-channel flow systems. The circulation system is an external circulation device, and the liquid inlet and outlet of the device are connected to the liquid storage tank. The single-channel flow system transports the reaction system in the liquid storage tank to the electrolysis system, and then transports the reaction system to another liquid storage tank after the electrolysis is completed, thereby forming a single-channel flow system.

[0004] At present, organic electrolysis devices are mostly used in sewage treatment, etc. For example, patent CN116589049A discloses a circulating electrolysis device for treating organic dissolved matter and some toxic substances in sewage to make the sewage harmless. In addition, patent CN206015107U discloses a special electrolysis device for electrolytic oxidation of organic matter. The purpose of this utility model invention is to provide a special electrolysis device for electrolytic oxidation of organic matter with low electrode consumption, long service life, and real-time monitoring. This invention is also used in sewage treatment. However, for some organic reactions that generate solid products, especially reactions at the hundred-gram or kilogram level, the current electrolysis devices are relatively lacking. The difficulty lies in the inability to separate the solid products in a timely manner, which often causes the forward reaction to proceed slowly and even generates by-products. Summary of the invention

[0005] In view of the above problems, the present invention provides a one-pot electrocatalytic continuous circulation device for organic synthesis, comprising an electrolytic cell, a filter, a liquid reservoir and an electrolytic unit, wherein the electrolytic cell is provided with an electrolytic unit, the electrolytic unit is immersed in an electrolyte, a plurality of anodes are provided inside the electrolytic unit, and a cathode is provided on the side of the electrolytic unit;

[0006] The filter and the liquid reservoir are located outside the electrolytic cell, the inlet of the filter is connected to the electrolytic cell through a first pipe, and the outlet of the filter is connected to the liquid inlet of the liquid reservoir through a second pipe, so that the material in the electrolytic cell is filtered through the filter, the solid product remains in the filter, and the filtered liquid enters the liquid reservoir; the liquid outlet of the liquid reservoir is connected to the electrolytic cell through a third pipe.

[0007] The present invention utilizes an external circulation system (filter and liquid reservoir) to realize the recirculation of electrolyte, inputs the solid-liquid mixture in the electrolytic cell into the filter for separation, filters out the solid product, and the liquid returns to the electrolytic cell through the liquid reservoir to continue the reaction, thereby making the reaction in the electrolytic cell more complete. By designing the size of the electrolytic cell, it is easy to expand to kilogram-level reactions.

[0008] Optionally, the electrolytic cell is detachable to facilitate the installation of the electrolytic unit. The electrolytic cell includes a main frame and a base. The main frame is a cube, and the top and bottom surfaces are empty, with only the sides being left. The base is located below the main frame, and the area of ​​the base is larger than the area of ​​the bottom surface of the main frame. The bottom of the main frame is sealed to the upper surface of the base to form an electrolytic cell for containing electrolyte.

[0009] Optionally, the electrolysis unit includes an upper fixed plate, a plurality of anodes, a lower fixed plate and a plurality of support rods from top to bottom, the upper fixed plate and the lower fixed plate are both horizontal, the bottom of the anode is connected to the upper fixed plate, and the bottom is connected to the lower fixed plate, and the plurality of anodes are evenly distributed in a matrix shape in the area between the upper fixed plate and the lower fixed plate; the top of the support rod is connected to the lower surface of the lower fixed plate, and the bottom is connected to the upper surface of the base, for supporting the electrolysis unit.

[0010] Further optionally, the electrolysis unit is a cube, the upper fixed plate and the lower fixed plate are both square, and the upper and lower positions correspond, so that the area between the upper fixed plate and the lower fixed plate is a cube-shaped electrolysis area, and a vertical cathode plate is provided on each of the four sides of the electrolysis area, and the top of the cathode plate is connected to the upper fixed plate, and the bottom is connected to the lower fixed plate.

[0011] Further optionally, the inlet of the first pipeline passes through the upper fixed plate and extends into the electrolysis area, which is convenient for extracting solids generated in the electrolysis area and is conducive to the reaction in the direction of generating solids; the outlet of the third pipeline is arranged above the upper fixed plate.

[0012] Further optionally, an agitator is provided in the electrolytic cell, and the motor of the agitator is fixed above the electrolytic cell, the stirring shaft extends into the electrolytic cell, and the stirring shaft passes through the upper fixed plate and the lower fixed plate in sequence, the stirring shaft portion within the electrolysis area is provided with at least one stirring paddle for stirring the liquid in the electrolysis area, and the stirring shaft portion below the lower fixed plate is provided with at least one stirring paddle for stirring the portion outside the electrolysis area.

[0013] Optionally, the anode is a graphite rod, and the cathode is selected from platinum sheet, iron sheet, zinc sheet, and stainless steel sheet;

[0014] The upper fixing plate and the lower fixing plate are made of a non-conductive material, such as a tetrafluoroethylene plastic plate.

[0015] Optionally, the filter is a hollow cylinder with removable circular end caps at both ends, and an inlet and an outlet are respectively provided on the end caps at both ends. At least one filter plate is provided in the filter, and the filter plate is circular and perpendicular to the axial direction of the filter. When the solid-liquid mixture flows through the filter, the filter plate retains the solid product and the liquid is filtered out.

[0016] Optionally, the liquid reservoir comprises a water inlet portion, a liquid storage portion and a liquid discharge portion from top to bottom, the water inlet portion comprises a vertical water inlet pipe and a liquid inlet port and a suction filtration port on both sides of the water inlet pipe, the water inlet pipe is a jacket structure, comprising an inner tube and an outer tube, the top of the inner tube is connected to the liquid inlet, the bottom of the inner tube is open, and the filtered liquid can be input into the liquid storage portion; the outer tube is connected to the suction filtration port, and the suction filtration port is connected to a diaphragm pump through a pipeline to provide power for suction filtration;

[0017] The bottom of the outer tube is connected to the liquid storage part, the bottom of the liquid storage part is connected to the liquid discharge part, and the liquid discharge part is provided with a valve to control the liquid storage device to release liquid to the electrolytic cell.

[0018] The one-pot electrocatalytic continuous circulation device provided by the present invention can be used to synthesize methylene quinone compounds, collect methylene quinone compounds in a filter, and react the aldehyde-substituted ring A compound, a phenol derivative and a secondary amine under electrolysis conditions to generate methylene quinone compounds. The synthesis route is as follows:

[0019]

[0020] Ring A is an aryl or heteroaryl group, and R1 is independently selected from a C1-C6 alkyl group; the electrolysis is carried out in a mixed solution of an aqueous solution of an inorganic salt and an organic solvent miscible with water, with a current of 100-200 mA and an electrolysis time of 5-20 h; preferably, the C1-C6 alkyl group is selected from a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group.

[0021] Further, ring A is at least one of phenyl, naphthyl, anthracenyl, benzanthryl, phenanthryl, pyrenyl, peryl, biphenyl, spirobifluorenyl, thienyl, furanyl, nitrophenyl, pyrimidinyl, benzofuranyl, indolyl, isoindolyl, carbazolyl, pyridinyl, quinolyl, isoquinolyl, pyrazolyl, indazolyl, benzopyrimidinyl, quinoxalinyl, pyrazinyl, phenazinyl, phenothiazinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, 1,3,5-triazinyl, 1,2,4-triazinyl, and 1,2,3-triazinyl. The inventors have found that the one-pot electrocatalytic continuous circulation device provided by the present invention can significantly improve the yield when preparing methylene quinone compounds by electrolysis, while the conventional heating method often results in a lower yield.

[0022] Optionally, the preparation of methylene quinone compounds includes the following steps: adding an aldehyde-substituted ring A compound, a phenol derivative, and a secondary amine to a mixed solution containing an aqueous solution of an inorganic salt and an organic solvent miscible with water, and electrolyzing the solution in an electrolytic cell to obtain a product methylene quinone compound.

[0023] Further optionally, the inorganic salt concentration in the aqueous solution of the inorganic salt is 0.01 mol / L, the inorganic salt is selected from at least one of potassium bicarbonate, sodium bicarbonate, ammonium chloride, sodium chloride, and potassium chloride, and the organic solvent is selected from at least one of acetonitrile, ethanol, propylene glycol, and ethylene glycol;

[0024] In the mixed solution, the volume ratio of the aqueous solution of the inorganic salt to the organic solvent is (3-5):(7-10).

[0025] Preferably, the electrolysis is first reacted under low current conditions (30-50 mA) for 4-5 h, and then the reaction is continued under high current conditions (100-200 mA) for 10-15 h.

[0026] Optionally, the molar ratio of the aldehyde-substituted ring A compound and the phenol derivative is (1-1.1):1, and the mass volume ratio of the aldehyde-substituted ring A compound and the mixed solution is (5-10) g:100 mL.

[0027] Preferably, before electrolysis, a redox medium such as TEMPO (tetramethylpiperidinyl oxide), Fe 2+ , Fe 3+ 、Co 2+ 、Co 3+ At least one of CuBr2 and CuI, the amount of the redox medium added is 5-10% of the molar amount of the phenol derivative. Adding a small amount of the redox medium can further improve the yield.

[0028] Optionally, the secondary amine is a piperidine derivative; the structural formula of the piperidine derivative is Wherein R3 is independently selected from at least one of H, C1-C6 alkyl, C2-C6 alkenyl, C2-C6 alkynyl, and C2-C6 ester, and R3 cannot all be H.

[0029] Further optionally, the C1-C6 alkyl group is selected from methyl, ethyl, propyl, butyl, pentyl, and hexyl; the C2-C6 alkenyl group is selected from vinyl, propenyl, and butenyl; the C2-C6 alkynyl group is selected from ethynyl, propynyl, and butynyl; and the C2-C6 ester group is selected from methyl formate, methyl acetate, ethyl formate, and ethyl acetate.

[0030] Further optionally, the amount of the secondary amine used is 5-10% of the molar amount of the phenol derivative.

[0031] The reaction mechanism of the synthesis of the present invention is that a phenol derivative is used as a model substrate, which is oxidized and deprotonated at the anode, and an amine is subjected to nucleophilic addition to form an iminium ion intermediate through dehydration and deprotonation. The iminium ion serves as an electrophilic reagent to attack the ring A compound substituted with an aldehyde group of a compound containing active hydrogen, and loses a proton, thereby obtaining a desired Mannich product. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic structural diagram of the one-pot electrocatalytic continuous circulation device for organic synthesis;

[0033] Figure 2 is a schematic diagram of an electrolysis unit;

[0034] Figure 3 is a schematic diagram of a water inlet pipe of a liquid reservoir;

[0035] Figure 4 The product obtained in Preparation Example 2 1 H-NMR spectrum;

[0036] Figure 5 The product obtained in Preparation Example 4 1 H-NMR spectrum;

[0037] Figure 6 The product obtained in Preparation Example 5 1 H-NMR spectrum.

[0038] In the accompanying drawings, 1-electrolytic cell, 2-filter, 3-liquid reservoir, 4-anode, 5-cathode, 6-first pipeline, 7-second pipeline, 8-third pipeline, 9-liquid inlet, 10-main frame, 11-base, 12-upper fixed plate, 13-lower fixed plate, 14-support rod, 15-stirring shaft, 16-filter plate, 17-liquid storage part, 18-liquid discharge part, 19-water inlet pipe, 20-suction port, 21-inner tube, 22-outer tube. DETAILED DESCRIPTION

[0039] This embodiment provides a one-pot electrocatalytic continuous circulation device for organic synthesis, such as Figure 1-Figure 3 As shown, it includes an electrolytic cell 1, a filter 2, a liquid reservoir 3 and an electrolytic unit. The electrolytic cell 1 is provided with an electrolytic unit, the electrolytic unit is immersed in an electrolyte, a plurality of anodes 4 are provided inside the electrolytic unit, and a cathode 5 is provided on the side of the electrolytic unit;

[0040] The filter 2 and the liquid reservoir 3 are located outside the electrolytic cell 1, the inlet of the filter 2 is connected to the electrolytic cell 1 through a first pipe 6, and the outlet of the filter 2 is connected to the liquid inlet 9 of the liquid reservoir 3 through a second pipe 7, so that the material in the electrolytic cell 1 is filtered through the filter 2, the solid product remains in the filter 2, and the filtered liquid enters the liquid reservoir 3; the liquid outlet of the liquid reservoir 3 is connected to the electrolytic cell 1 through a third pipe 8.

[0041] The electrolytic cell 1 is detachable, which is convenient for the installation of the electrolytic unit. The electrolytic cell 1 includes a main frame 10 and a base 11. The main frame 10 is a cube, and the top and bottom surfaces are both empty, with only the sides around. The base 11 is below the main frame 10, and the area of ​​the base 11 is larger than the area of ​​the bottom surface of the main frame 10. The bottom of the main frame 10 is sealed and docked with the upper surface of the base 11 to form an electrolytic cell 1 for containing electrolyte.

[0042] A circle of slots is set on the upper surface of the base 11 corresponding to the bottom edge of the main frame 10, and a sealing gasket is set in the slot. The bottom edge of the main frame 10 is inserted into the slot, and a downward force is applied to the top of the main frame 10 to ensure the sealing of the main frame 10 and the base 11.

[0043] The electrolysis unit includes an upper fixed plate 12, a plurality of anodes 4, a lower fixed plate 13 and a plurality of support rods 14 from top to bottom. The upper fixed plate 12 and the lower fixed plate 13 are both horizontal. The bottom of the anode 4 is connected to the upper fixed plate 12, and the bottom is connected to the lower fixed plate 13. The plurality of anodes 4 are evenly distributed in a matrix in the area between the upper fixed plate 12 and the lower fixed plate 13; the top of the support rod 14 is connected to the lower surface of the lower fixed plate 13, and the bottom is connected to the upper surface of the base 11, which is used to support the electrolysis unit. The number of anodes 4 is adjusted according to the magnitude of the reaction. The anode 4 and the cathode 5 are connected to the positive and negative poles of the power supply, respectively.

[0044] The electrolysis unit is a cube, and the upper fixed plate 12 and the lower fixed plate 13 are both square, and the upper and lower positions correspond, so that the area between the upper fixed plate 12 and the lower fixed plate 13 is a cube-shaped electrolysis area, and a vertical cathode 5 plate is respectively provided on the four sides of the electrolysis area, and the top of the cathode 5 plate is connected to the upper fixed plate 12, and the bottom is connected to the lower fixed plate 13.

[0045] The inlet of the first pipe 6 passes through the upper fixed plate 12 and extends into the electrolysis area, so as to facilitate the extraction of solids generated in the electrolysis area and facilitate the reaction to proceed in the direction of generating solids;

[0046] The outlet of the third pipe 8 is arranged above the upper fixed plate 12, and the returned electrolyte is input into the electrolytic cell 1, so as to avoid a large impact on the liquid environment in the electrolysis area, which is conducive to the stable reaction.

[0047] The electrolytic cell 1 is provided with an agitator, the motor of the agitator is fixed above the electrolytic cell 1, the agitator shaft 15 extends into the electrolytic cell 1, and the agitator shaft 15 passes through the upper fixed plate 12 and the lower fixed plate 13 in sequence. The portion of the agitator shaft 15 in the electrolysis area is provided with at least one agitator paddle for stirring the liquid in the electrolysis area, and the portion of the agitator shaft 15 below the lower fixed plate 13 is provided with at least one agitator paddle for stirring the portion outside the electrolysis area.

[0048] The anode 4 is a graphite rod, and the cathode 5 is selected from platinum sheet, iron sheet, zinc sheet, and stainless steel sheet;

[0049] The upper fixing plate 12 and the lower fixing plate 13 are made of a non-conductive material, such as a tetrafluoroethylene plastic plate.

[0050] As a specific embodiment, the main frame 10 is a cube, the upper fixed plate 12 and the lower fixed plate 13 are both square, and the electrolysis area is a cube area between the upper and lower fixed plates 13. The four sides of the cube area are respectively provided with a cathode 5, and the two adjacent cathodes 5 do not contact each other, and the anodes 4 do not contact each other, and the anode 4 does not contact the cathode 5 to avoid short circuit. The connection between the upper and lower fixed plates 13 and the anode 4 can be screw connection or jack plug-in. For example, the upper and lower fixed plates 13 are provided with a concave hole that is concave upward or downward at the position corresponding to the anode 4, and the two ends of the anode 4 are respectively inserted into the concave hole. The cathode 5 can also be connected by a slot. The stirring shaft 15 is vertically inserted into the middle of the electrolysis area, and the anode 4 is not set within the stirring range of the stirring paddle. Four support rods 14 are provided below the lower fixed plate 13, respectively close to the four vertices of the lower fixed plate 13, and a stirring paddle is provided at the center of the four support rods 14 to stir the liquid space outside the electrolysis area.

[0051] When in use, under the action of stirring, the electrolyte in the electrolysis area can fully contact the anode 4 and the cathode 5. Multiple anodes 4 (graphite rods) are arranged in parallel and surrounded by 5 cathodes. The gap between the graphite rods and the 5 cathodes is adjustable, providing a higher ratio of electrode surface area to reactor volume, making the electrochemical process more efficient.

[0052] The filter 2 is a hollow cylinder with removable circular end caps at both ends. The end caps at both ends are respectively provided with an inlet and an outlet. At least one filter plate 16 is provided in the filter 2. The filter plate 16 is circular and perpendicular to the axial direction of the filter 2. When the solid-liquid mixture flows through the filter 2, the filter plate 16 retains the solid product and the liquid is filtered out.

[0053] Preferably, the filter disc 16 is close to the outlet of the filter 2, and the filter disc 16 is a conventional glass sand core, and the mesh number of the glass sand core is determined according to the solid particle size to be filtered.

[0054] The liquid reservoir 3 includes a water inlet, a liquid storage part 17 and a liquid discharge part 18 from top to bottom. The water inlet includes a vertical water inlet pipe 19 and a liquid inlet port 9 and a suction port 20 on both sides of the water inlet pipe 19. The water inlet pipe 19 is a sleeve structure, including an inner tube 21 and an outer tube 22. The top of the inner tube 21 is connected to the liquid inlet 9, and the bottom of the inner tube 21 is open, so that the filtered liquid can be input into the liquid storage part 17; the outer tube 22 is connected to the suction port 20, and the suction port 20 is connected to a diaphragm pump through a pipeline to provide power for suction filtration;

[0055] The bottom of the outer tube 22 is connected to the liquid storage part 17 , and the bottom of the liquid storage part 17 is connected to the liquid discharge part 18 . The liquid discharge part 18 is provided with a valve to control the liquid storage device 3 to release liquid to the electrolytic cell 1 .

[0056] The liquid inlet 9 and the filtration port 20 are both horizontal, the inner tube 21 and the outer tube 22 are both vertical, the bottom end of the inner tube 21 is higher than the bottom end of the outer tube 22, and the height of the filtration port 20 is between the top and bottom ends of the inner tube 21.

[0057] The liquid storage portion 17 is in an upright shuttle shape to increase the liquid storage space; the bottom of the liquid discharge portion 18 is a liquid outlet and is connected to the third pipeline 8 .

[0058] When in use, the diaphragm pump provides suction power through the suction port 20, and the solid-liquid mixture in the electrolysis area is sucked into the filter 2 along the first pipe 6. The filter 2 can be placed upright (with the inlet facing upward). At this time, the filter plate 16 is horizontal, and the solid-liquid mixture is filtered. The solid is left on the filter plate 16, and the liquid enters the liquid storage part 17 along the second pipe 7, the liquid inlet 9, and the inner layer pipe 21 in sequence. When it is necessary to replenish the electrolytic cell 1, open the valve on the liquid discharge pipe, and the electrolyte in the liquid storage part 17 can return to the electrolytic cell 1 along the third pipe 8. When there is a lot of solid accumulation in the filter 2, the end cover can be removed to clean the inside of the filter 2 and the filter plate 16.

[0059] The one-pot electrocatalytic continuous circulation device for organic synthesis provided in the above embodiment was used to carry out the operation of synthesizing methylene quinone compounds in the following preparation example:

[0060] Preparation Example 1

[0061]

[0062] Add 5.83g (0.055mol) of benzaldehyde, 9.90g (0.048mol) of 2,6-di-tert-butylphenol, 1.75g ​​(0.024mol) of diethylamine, 30ml of 0.01mol / L KHCO3 solution of electrolyte, and 70ml of acetonitrile solvent into a 150ml electrolytic cell, insert the electrode anode graphite gang and the cathode zinc sheet, connect the constant potential instrument, adjust the constant potential instrument parameters to a constant current of 50mA, react for 4-5h, and detect the reaction by TLC; continue to adjust the parameters to gradually increase the constant current to 100mA, and then react for about 15h. Take out the solid from the filter, which is the crude product of the reaction, extract the crude product with dichloromethane, distill under reduced pressure, and chromatograph on a silica gel column to obtain 10.26g of a yellow solid product with a product purity of 97.3% and a yield of 81.4%.

[0063] Preparation Example 2

[0064] The other conditions were the same as those in Preparation Example 1. The difference was that diethylamine was replaced with 2.4 mmol of 2-methylpiperidine. The purity of the product in Preparation Example 3 was 98.2% and the yield was 80.3%. 1 H-NMR (CDCl3) Figure 4 As shown, the structure of the obtained product is correct. It proves that the method does produce the desired product.

[0065] Preparation Example 3

[0066] The other conditions were the same as those in Preparation Example 1. The difference was that 0.75 g of TEMPO (0.0048 mol) as a redox medium was added to the reaction system. The purity of the final product was 97.6% and the yield was 83.2%.

[0067] Preparation Example 4

[0068]

[0069] The other conditions were the same as those in Preparation Example 2, except that the ring A compound was terephthalaldehyde. The final product had a purity of 97.2% and a yield of 70.6%. 1 H-NMR spectrum Figure 5 As shown, it is proved that the structure of the obtained product is correct.

[0070] Preparation Example 5

[0071]

[0072] The other conditions were the same as those in Preparation Example 2. The difference was that the ring A compound was thiophene-2-carboxaldehyde. The final product had a purity of 98.5% and a yield of 85.3%. 1 H-NMR (CDCl3) Figure 6 As shown, it is proved that the structure of the obtained product is correct.

[0073] Comparative Example 1

[0074] The other conditions were the same as those in Preparation Example 7, except that the reaction conditions were changed from electrolysis to heating, specifically, the reactants thiophene-2-carboxaldehyde and 2,6-di-tert-butylphenol were added to the solvent benzene, 2-methylpiperidine was slowly added, the addition was completed over 2 hours, the temperature was raised to 120°C, the reaction was continued for 18 hours, the temperature was raised to 150°C, the reaction was continued for 3 hours, and the crude product was distilled under reduced pressure. After column chromatography, the crude product was recrystallized with a mixed solvent of ethanol, petroleum ether and acetonitrile in a volume ratio of 3:1:1, and washed to obtain the product. The product purity was 98.2%, and the yield was 65.3%.

Claims

1. A one-pot electrocatalytic continuous circulation device for organic synthesis, characterized in that: The invention comprises an electrolytic cell, a filter, a liquid storage device and an electrolytic unit. The electrolytic cell is provided with an electrolytic unit, the electrolytic unit is immersed in an electrolyte, a plurality of anodes are provided inside the electrolytic unit, and a cathode is provided on the side of the electrolytic unit. The filter and the liquid reservoir are located outside the electrolytic cell, the inlet of the filter is connected to the electrolytic cell through a first pipe, and the outlet of the filter is connected to the liquid inlet of the liquid reservoir through a second pipe, so that the material in the electrolytic cell is filtered through the filter, the solid product remains in the filter, and the filtered liquid enters the liquid reservoir; the liquid outlet of the liquid reservoir is connected to the electrolytic cell through a third pipe.

2. The one-pot electrocatalytic continuous circulation device according to claim 1, characterized in that: The electrolytic cell is detachable, which is convenient for the installation of the electrolytic unit. The electrolytic cell includes a main frame and a base. The main frame is a cube, and the top and bottom surfaces are both empty, with only the sides around. The base is located below the main frame, and the area of ​​the base is larger than the area of ​​the bottom surface of the main frame. The bottom of the main frame is sealed and docked with the upper surface of the base to form an electrolytic cell for containing electrolyte.

3. The one-pot electrocatalytic continuous circulation device according to claim 1, characterized in that: The electrolysis unit comprises an upper fixed plate, a plurality of anodes, a lower fixed plate and a plurality of support rods from top to bottom. The upper fixed plate and the lower fixed plate are both horizontal. The bottom of the anode is connected to the upper fixed plate, and the bottom is connected to the lower fixed plate. The plurality of anodes are evenly distributed in a matrix shape in the area between the upper fixed plate and the lower fixed plate. The top of the support rod is connected to the lower surface of the lower fixed plate, and the bottom is connected to the upper surface of the base, so as to support the electrolysis unit.

4. The one-pot electrocatalytic continuous circulation device according to claim 3, characterized in that: The electrolysis unit is a cube, and the upper fixed plate and the lower fixed plate are both square, and the upper and lower positions correspond, so that the area between the upper fixed plate and the lower fixed plate is a cube-shaped electrolysis area, and a vertical cathode plate is respectively provided on the four sides of the electrolysis area, and the top of the cathode plate is connected to the upper fixed plate, and the bottom is connected to the lower fixed plate.

5. The one-pot electrocatalytic continuous circulation device according to claim 4, characterized in that: The inlet of the first pipeline passes through the upper fixed plate and extends into the electrolysis area, which is convenient for extracting solids generated in the electrolysis area and is conducive to the reaction in the direction of generating solids; the outlet of the third pipeline is arranged above the upper fixed plate.

6. The one-pot electrocatalytic continuous circulation device according to claim 4, characterized in that: An agitator is provided in the electrolytic cell, and the motor of the agitator is fixed above the electrolytic cell. The stirring shaft extends into the electrolytic cell, and the stirring shaft passes through the upper fixed plate and the lower fixed plate in sequence. The stirring shaft portion in the electrolysis area is provided with at least one stirring paddle for stirring the liquid in the electrolysis area, and the stirring shaft portion below the lower fixed plate is provided with at least one stirring paddle for stirring the portion outside the electrolysis area.

7. The one-pot electrocatalytic continuous circulation device according to claim 4, characterized in that: The anode is a graphite rod, and the cathode is selected from platinum sheets, iron sheets, zinc sheets, and stainless steel sheets; the materials of the upper fixing plate and the lower fixing plate are non-conductive.

8. The one-pot electrocatalytic continuous circulation device according to claim 1, characterized in that: The filter is a hollow cylinder with removable circular end caps at both ends. The end caps at both ends are respectively provided with an inlet and an outlet. At least one filter plate is provided in the filter. The filter plate is circular and perpendicular to the axial direction of the filter. When the solid-liquid mixture flows through the filter, the filter plate retains the solid product and the liquid is filtered out.

9. The one-pot electrocatalytic continuous circulation device according to claim 1, characterized in that: The liquid reservoir comprises a water inlet, a liquid storage and a liquid discharge part from top to bottom. The water inlet comprises a vertical water inlet pipe and a liquid inlet and a suction filter port on both sides of the water inlet pipe. The water inlet pipe is a sleeve structure, comprising an inner tube and an outer tube. The top of the inner tube is connected to the liquid inlet, and the bottom of the inner tube is open, so that the filtered liquid can be input into the liquid storage part; the outer tube is connected to the suction filter port, and the suction filter port is connected to a diaphragm pump through a pipeline to provide power for suction filtration; The bottom of the outer tube is connected to the liquid storage part, the bottom of the liquid storage part is connected to the liquid discharge part, and the liquid discharge part is provided with a valve to control the liquid storage device to release liquid to the electrolytic cell.

10. The one-pot electrocatalytic continuous circulation device according to claim 1, characterized in that: The one-pot electrocatalytic continuous circulation device can be used to synthesize methylene quinone compounds. The methylene quinone compounds are collected in a filter. The ring A compound substituted with an aldehyde group, a phenol derivative and a secondary amine react under electrolysis conditions to generate methylene quinone compounds. The synthesis route is as follows: Ring A is an aryl group or a heteroaryl group, and R1 is independently selected from a C1-C6 alkyl group; the electrolysis is carried out in a mixed solution of an aqueous solution of an inorganic salt and an organic solvent miscible with water, with a current of 100-200 mA and an electrolysis time of 5-20 hours.

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