Semiconductor heterogeneous photoelectrocatalytic flow reactor and use thereof

Abstract

The application discloses a semiconductor heterogeneous photoelectrocatalytic flow reactor and application thereof. The reactor has good light permeability and electric conductivity, can fully utilize light energy and electric energy, and has uniform light-generated current density distribution (decay rate is less than 10%) and excellent mass transfer performance. The total area of the photoanode can be increased according to requirements, so that the flow reactor for photoelectrocatalytic reaction under different scales is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectrochemical reaction equipment, in particular to a semiconductor heterogeneous photoelectrocatalytic flow reactor and application thereof, which can be applied to continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis. BACKGROUND

[0002] Semiconductor heterogeneous photoelectrocatalysis has attracted extensive attention in the field of organic synthesis in recent years due to its environmental friendliness and sustainable development concept. Compared with traditional synthesis methods, semiconductor photoelectrocatalysis technology uses inexpensive and recyclable semiconductor catalysts to generate photo-generated holes with flexible oxidation ability under light to drive single-electron oxidation processes, obtain free radicals with adjustable electrical properties and steric hindrance, and inhibit the recombination of photo-generated holes and photo-generated electrons inside the semiconductor by applying an external electric field to improve the reaction rate. Therefore, under mild conditions, low-value substrates can be converted into high-value fine chemicals with high selectivity, which has great application potential.

[0003] With the rapid development of photoelectrochemical organic synthesis, the demand for efficient photoelectrochemical reactors is also gradually increasing. Semiconductor photoelectrocatalytic reaction is a heterogeneous catalytic reaction, which is affected by processes such as photon transfer, charge transfer, electrode surface and inter-electrode mass transfer. Therefore, the electrode specific surface area of the reactor, the effective absorption of the photocatalyst to light, and the mass transfer characteristics have high requirements. It is necessary to develop a continuous flow photoelectrochemical reactor with simple structure, uniform distribution of photo-generated current density, and excellent mass transfer performance to realize photoelectrocatalytic organic synthesis reactions of different scales.

[0004] However, since the photoelectrocatalytic flow reactor requires the cooperation of photo and electricity, the reactor must have good light transmittance and electrical conductivity, which poses high requirements for the design of the reactor. Many existing photochemical reactors (such as the patent specification with publication number CN113070013A) only achieve good light transmittance but lack electrical conductivity, so they cannot apply a positive bias to the semiconductor catalyst to accelerate carrier migration and inhibit carrier recombination to increase the reaction rate. This greatly limits the use of many semiconductors with desired reaction band gap matching, high carrier recombination rate, or slow carrier migration, and the reaction rate of the reactor cannot be further improved.

[0005] In addition, in photoelectrochemical reactions, the reaction rate is controlled by the photocurrent of the photoanode surface. To obtain a larger photocurrent, a higher photoanode surface area is required. However, as the photoanode surface area increases, the photogenerated current density and the uniformity of the flow rate distribution on the photoanode surface will rapidly decrease, which not only fails to further increase the total photocurrent, but also deteriorates the mass transfer performance. Therefore, the photoanode surface area used in the existing reactors (such as the patent specification with publication number CN112452272A) is small, and it is impossible to realize photoelectrocatalytic reactions with large photogenerated current. SUMMARY

[0006] In view of the above technical problems and the deficiencies in the field, the present application provides a semiconductor heterogeneous photoelectrocatalytic flow reactor, which has good light transmittance and electrical conductivity, can fully utilize light energy and electrical energy, has uniform photogenerated current density distribution (decay rate less than 10%), excellent mass transfer performance, and the total area of the photoanode can be increased according to the requirements to realize photoelectrocatalytic flow reactors of different scales.

[0007] A semiconductor heterogeneous photoelectrocatalytic flow reactor, comprising:

[0008] A photoanode loaded with a semiconductor catalyst, used to connect the positive pole of a power supply;

[0009] An anode substrate with first through holes corresponding to the number of photoanodes and completely covered by the photoanodes; one side of the anode substrate is sealed to the photoanodes corresponding to the positions of the first through holes, and the opposite side is sealed to the cathode substrate;

[0010] A cathode substrate with a liquid inlet cavity on one side close to the anode substrate and a cathode electrode for connecting the negative pole of the power supply embedded in the position corresponding to the first through holes; each group of cathode electrodes and photoanodes enclose a space region of the first through hole as a reaction chamber, and the semiconductor catalyst loaded on the photoanode is located in the reaction chamber; the cathode substrate is provided with an outlet communicating with the reaction chamber and an inlet channel groove connecting the liquid inlet cavity and the reaction chamber; the bottom of the liquid inlet cavity is provided with a liquid inlet groove with an inlet; the liquid inlet cavity is provided with a first flow divider with one end communicating with the liquid inlet groove and the other end opening towards the inlet channel groove; and the first flow divider is laid with filter paper completely covering the liquid inlet groove.

[0011] The semiconductor heterogeneous photoelectrocatalytic flow reactor, the reaction liquid entering the reactor must pass through the inlet, the liquid inlet groove, and then flow through the filter paper to the first shunt opening, and then flow into the reaction chamber through the first shunt opening and the inlet channel groove. Because the flow resistance of the filter paper is large, the reaction liquid must first fill the inlet groove, and then flow to the reaction chamber through the filter paper after being uniformly distributed in the inlet groove, so as to achieve the effect of uniformly distributing the flow rate of the reaction liquid. In an embodiment, the pore size of the filter paper is 0.1-5 μm.

[0012] The semiconductor heterogeneous photoelectrocatalytic flow reactor, the photoanode can be a conductive glass, one side of which is a conductive surface loaded with a semiconductor catalyst, and the other side is a glass non-conductive surface, wherein a conductive tape is also attached to the conductive surface, and the conductive tape extends to the glass non-conductive surface.

[0013] Further, the semiconductor heterogeneous photoelectrocatalytic flow reactor can also include an anode current collector plate connected to the positive pole of an external power supply;

[0014] The anode current collector plate is provided with a hole through which a hollow conductive frame for transmitting light passes;

[0015] One end of the conductive frame is folded over for fixed connection with the anode current collector plate, and the other end passes through the anode current collector plate to connect the conductive tape.

[0016] The present application can increase the total area of the photoanode by limiting the width of the photoanode and increasing the length of the photoanode, so as to ensure that the maximum decay rate of the photo-generated current density is less than 10%. In a preferred embodiment, the width of the photoanode of the semiconductor heterogeneous photoelectrocatalytic flow reactor is not more than 60 mm. The semiconductor catalyst can be loaded in the central region of the conductive surface. The semiconductor catalyst is not present in the region 1-2 mm around the conductive surface, which is used for attaching the conductive tape. The conductive tape can extend along the side of the conductive glass to the edge of the glass non-conductive surface 3-5 mm away. In this design, the distance between the semiconductor catalyst on the surface of the conductive glass and the conductive copper tape around the periphery is not more than 30 mm, and the surface of the conductive glass does not exhibit a significant voltage drop, so that the photo-generated current density can have good uniformity.

[0017] The semiconductor heterogeneous photoelectrocatalytic flow reactor can also include a cathode current collector plate connected to the negative pole of an external power supply;

[0018] The cathode base plate is provided with a cathode groove corresponding to the embedded cathode electrode, and the bottom of the cathode groove is provided with a second through hole for bolted connection and conduction between the cathode current collector plate and the cathode electrode.

[0019] In an embodiment, the semiconductor heterogeneous photoelectrocatalytic flow reactor, the cathode base plate is also provided with an outlet flow channel groove for connecting the outlet flow channel groove and the reaction chamber.

[0020] An outlet is arranged at the bottom of the liquid outlet cavity.

[0021] A second flow divider is arranged in the liquid outlet cavity, one end of which is communicated with the liquid outlet groove, and the other end is opened towards the outlet flow channel groove.

[0022] The semiconductor heterogeneous photoelectrocatalytic flow reactor has multiple photoanodes, and the reaction chambers are also multiple and in series connection between each other and communicated through the transition flow channel grooves arranged on the cathode substrate.

[0023] In an embodiment, the semiconductor heterogeneous photoelectrocatalytic flow reactor further has an annular groove arranged on the side of the cathode substrate close to the anode substrate, which can place a sealing ring and enclose the liquid inlet cavity, the cathode electrode, the outlet and the inlet flow channel groove, so as to realize the overall sealing of the reaction system.

[0024] The application further provides an application of the semiconductor heterogeneous photoelectrocatalytic flow reactor in the field of continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis.

[0025] As a general inventive concept, the application further provides a continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis method, which adopts the semiconductor heterogeneous photoelectrocatalytic flow reactor, connects the outlet and the inlet through a circulating pump to form a circulating flow path, and circulates the reaction liquid in the circulating flow path.

[0026] In an embodiment, the continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis method has an initial reaction liquid containing 4,6-dimethyl-2-methylsulfonyl pyrimidine, potassium trifluoroacetate, trifluoroacetic acid and acetonitrile, a reaction product being 4,6-dimethoxy-2-methylsulfonyl-5-trifluoromethyl pyrimidine, and a semiconductor catalyst being Mo-doped tungsten trioxide, and the photoelectric reaction condition being 390-400 nm wavelength light irradiation and a voltage of 1-3 V.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The reactor has good light transmittance and conductivity, can utilize the synergistic effect of photoelectricity to perform the reaction, expand the use range of the semiconductor catalyst, and improve the reaction effect. Meanwhile, the light-generated current density decay rate is less than 10%, and the mass transfer performance is excellent. In addition, the total area of the photoanode can be increased by increasing the number of chambers according to the requirement, so as to realize the flow reactor for photoelectric catalytic reaction in different scales. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 It is an explosion structure schematic view of a semiconductor heterogeneous photoelectrocatalytic flow reactor of the application;

[0030] Figure 2 For Figure 1 The structure diagram of the anode substrate in the semiconductor heterogeneous photoelectrocatalytic flow reactor shown in FIG. 1;

[0031] Figure 3 For Figure 1 The enlarged structure diagram of the lower half of the cathode substrate in the semiconductor heterogeneous photoelectrocatalytic flow reactor shown in FIG. 1;

[0032] Figure 4 For Figure 1 The flow direction diagram of the reaction solution in the liquid inlet cavity in the semiconductor heterogeneous photoelectrocatalytic flow reactor shown in FIG. 1. DETAILED DESCRIPTION

[0033] The present application will be further described below in conjunction with the drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present application and not to limit the scope of the present application.

[0034] Referring to Figure 1 A semiconductor heterogeneous photoelectrocatalytic flow reactor with two reaction chambers in upper and lower positions comprises a cathode current collector plate 7, a cathode substrate 6, an anode substrate 2, an anode current collector plate 3 and a conductive frame 4 arranged in sequence. The side surface of the cathode current collector plate 7 and the anode current collector plate 3 are provided with a convex portion 21, and a wiring hole 22 with an inner diameter of 2-3 mm is formed in the convex portion 21 for inserting a connecting wire connected to a power supply electrode. Among them, the anode current collector plate 3 is connected to the positive electrode of the power supply, and the cathode current collector plate 7 is connected to the negative electrode of the power supply. The conductive frame 4 is hollow for light transmission.

[0035] The material of the anode substrate 2 includes but is not limited to polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, etc., and the thickness can be between 10-20 mm. In combination Figure 2The anode substrate 2 has two first through holes 8, and the thickness of the first through holes 8 can be 2-5 mm (the thickness is the height of each reaction chamber). The surface of the anode substrate 2 facing the cathode substrate 6 is a plane, and the other surface opposite to the plane forms a step 23 around the four sides of the first through hole 8. The width of the step 23 can be 5-15 mm. A sealing ring 24 with a thickness of 0.5-1 mm is arranged on the step 23. A photoanode 1 for connecting the positive pole of the power supply is arranged on the sealing ring 24, and the photoanode 1 can completely cover the corresponding first through hole 8. The extension size of the step 23 is the same as that of the corresponding photoanode 1, and the distance between the two steps 23 is 15-30 mm. The photoanode 1 is conductive glass, including but not limited to FTO glass and ITO glass, and the width is 35-60 mm, the length is 80-120 mm, and the square resistance is 7-10 ohms. The surface of the photoanode 1 facing the sealing ring 24 is a conductive surface loaded with a semiconductor catalyst, and the other surface opposite to the conductive surface is a non-conductive glass surface. The semiconductor catalyst includes but is not limited to titanium dioxide, tungsten trioxide, bismuth vanadate, zinc oxide, etc., and is loaded in the central region of the conductive surface. There is no semiconductor catalyst at 1-2 mm around the conductive surface, and a conductive copper tape is attached thereon. The conductive copper tape extends along the side of the conductive glass to the edge of the non-conductive glass surface by 3-5 mm. In this design, the distance between the semiconductor catalyst on the surface of the conductive glass and the conductive copper tape around the conductive glass surface will not exceed 30 mm, and the surface of the conductive glass will not show a significant voltage drop, so that the photo-generated current density can have good uniformity.

[0036] The anode substrate 2 is tightly attached to the anode current collector plate 3. The material of the anode current collector plate 3 includes but is not limited to aluminum alloy, titanium alloy, stainless steel, etc., and the thickness can be 8-15 mm. The anode current collector plate 3 has a hole (which can be referred to as a light transmission hole, and the shape is the same as that of the photoanode 1, and the photoanode 1 is arranged corresponding to the light transmission hole) through which the conductive frame 4 passes. Specifically, one end of the conductive frame 4 is folded to be fixedly connected to the anode current collector plate 3, and the other end passes through the anode current collector plate 3 and is pressed on the non-conductive glass surface of the photoanode 1 to form a close contact with the conductive copper tape and be consistent with the shape of the sealing ring 24. The material of the conductive frame 4 includes but is not limited to aluminum alloy, titanium alloy, stainless steel, etc. The total height of the conductive frame 4 is 5-15 mm greater than the sum of the height of the step 23 of the anode substrate 2 and the height of the anode current collector plate 3, so that the top of the conductive frame 4 can be obviously higher than the anode current collector plate 3. The width of the folded edge of the conductive frame 4 is 5-10 mm, and there are bolt holes on the folded edge for fixing the conductive frame 4 on the anode current collector plate 3 and forming a conductive path of the positive pole of the power supply-anode current collector plate 3-bolt-conductive frame 4-conductive copper tape-conductive glass conductive surface.

[0037] A light source with a wavelength of 390-770 nm and a power of 0-500 W can be provided beside the anode current collector plate 3. The light source irradiates the conductive glass through the hollow area of the conductive frame 4 and the light transmission hole of the anode current collector plate 3 to provide the required light for the reaction.

[0038] The other side of the anode substrate 2 is closely attached to the cathode substrate 6. In combination Figure 3 , the cathode substrate 6 is symmetrical up and down. The side of the cathode substrate 6 facing the anode substrate 2 is provided with two cathode grooves 16 with a depth of 5-10 mm at the positions corresponding to the two first through holes 8. The bottom of each cathode groove 16 is provided with two second through holes 17 with a diameter of 6-10 mm, which can be threaded holes. A sealing groove is provided around the second through hole 17 at the bottom of the cathode groove 16, and an O-ring is installed in the sealing groove. The cathode electrode 5 is embedded in the cathode groove 16 one by one. The cathode electrode 5 has the same shape as the cathode groove 16, and the material of the cathode electrode 5 includes but is not limited to titanium alloy, graphite, etc., and the surface is plated with a catalyst including but not limited to platinum, palladium, etc. The back of the cathode electrode 5 has two threaded holes of M6-M10, which are aligned with the second through holes 17 in the cathode groove 16. The space region of the first through hole 8 surrounded by each group of cathode electrodes 5 and the photoanode 1 is a reaction chamber, and the semiconductor catalyst loaded on the photoanode 1 is located in the reaction chamber. The material of the cathode current collector 7 includes but is not limited to stainless steel, titanium alloy, aluminum alloy, etc., and is closely attached to the cathode substrate 6. The cathode current collector 7 is connected to the cathode electrode 5 by a bolt fixed connection through the second through hole 17, realizing the conductive path of the cathode electrode 5-bolt-cathode current collector 7-power negative electrode. The side of the cathode substrate 6 facing the anode substrate 2 is provided with a transition flow channel 19 with a depth of 0.5-2 mm between the two cathode grooves 16, and the upper and lower reaction chambers are connected in series through the transition flow channel 19. In further combination Figure 4, the one side of the cathode substrate 6 facing the anode substrate 2 is below the cathode groove 16 to open the liquid inlet cavity 11 and the inlet flow channel groove 9 connecting the liquid inlet cavity 11 and the lower reaction chamber. The liquid inlet cavity 11 is coaxial with the cathode groove 16, with a depth of 3-6 mm, a width of 2-4 mm longer than the cathode groove 16, and a length of 6-20 mm. The liquid inlet cavity 11 is provided with a liquid inlet groove 12 with an inlet 13 with an inner diameter of 1-2 mm in the middle of the bottom. The liquid inlet groove 12 has a depth of 1-3 mm, a width equal to the width of the reaction chamber, and a length of 2-3 mm. The liquid inlet cavity 11 is provided with a first flow divider 15 having one end communicating with the liquid inlet groove 12 and the other end opening towards the inlet flow channel groove 9. The first flow divider 15 has a bottom surface size consistent with the liquid inlet cavity 11, an opening height of 0.1-1 mm, and an opening position corresponding to the liquid inlet groove 12 and consistent with the length and width of the liquid inlet groove 12. A filter paper 14 is laid under the first flow divider 15 to completely cover the liquid inlet groove 12, and the first flow divider 15 can press the filter paper 14. The filter paper 14 is made of polytetrafluoroethylene, nylon, polypropylene, etc., but is not limited thereto, has a pore size of 0.1-5 μm, and has a length and width independently 2-3 mm larger than those of the liquid inlet groove 12. The one side of the cathode substrate 6 facing the anode substrate 2 is above the cathode groove 16 to open the liquid outlet cavity and the outlet flow channel groove 18 connecting the liquid outlet cavity and the upper reaction chamber. Similar to the structure in the liquid inlet cavity 11, the liquid outlet cavity is coaxial with the cathode groove 16, has a depth of 3-6 mm, a width of 2-4 mm longer than the cathode groove 16, and a length of 6-20 mm. The outlet 10 has an inner diameter of 1-2 mm and is located in the center of the liquid outlet groove provided in the bottom of the liquid outlet cavity. The liquid outlet groove has a depth of 1-3 mm, a width equal to the width of the reaction chamber, and a length of 2-3 mm. The liquid outlet cavity is provided with a second flow divider having one end communicating with the liquid outlet groove and the other end opening towards the outlet flow channel groove 18. No filter paper is provided under the second flow divider. The second flow divider has a bottom surface size consistent with the liquid outlet cavity, an opening height of 0.1-1 mm, and an opening position corresponding to the liquid outlet groove and consistent with the length and width of the liquid outlet groove. The materials of the first flow divider 15 and the second flow divider include stainless steel, titanium alloy, polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, etc., but are not limited thereto. The first flow divider 15 and the second flow divider can be provided to uniformly distribute the flow rate to optimize the mass transfer performance. The one side of the cathode substrate 6 close to the anode substrate 2 is also provided with an annular groove 20, and a sealing ring is arranged in the annular groove 20. The annular groove 20 surrounds the liquid inlet cavity 11, the inlet flow channel groove 9, the two cathode electrodes 5, the outlet flow channel groove 18, and the liquid outlet cavity to realize overall sealing of the reaction system. The reaction liquid can enter and exit the reactor through the inlet 13, the liquid inlet groove 12, the filter paper 14, the first flow divider 15, the inlet flow channel groove 9, the lower reaction chamber, the transition flow channel groove 19, the upper reaction chamber, the outlet flow channel groove 18, the second flow divider, the liquid outlet groove, and the outlet 10. Since the flow resistance of the filter paper 14 is large, the reaction liquid must first fill the liquid inlet groove 12, and then flow to the reaction chamber after being uniformly distributed in the liquid inlet groove 12, so as to achieve the effect of uniformly distributing the flow rate of the reaction liquid.

[0039] The reactor of the embodiment has two chambers, each of which has a photoanode 1 at the top and a cathode electrode 5 at the bottom, and is separated by an anode substrate 2 by 2-5 mm for the reaction solution to flow therebetween for reaction. The photoanode 1 is connected to the anode current collector plate 3 with a light transmission hole via the hollow conductive frame 4 to ensure good light transmission and electrical contact of the photoanode 1. The cathode electrode 5 is connected to the cathode current collector plate 7 via a bolt to ensure effective electrical connection of the cathode electrode 5. At the same time, a flow divider is arranged at the inlet and outlet of the reactor to evenly distribute the flow rate. The reactor has uniform photoelectric current density (maximum decay rate less than 10%), excellent mass transfer performance, and can double the total area of the photoanode (more than 50 cm 2 , the area of a single reaction chamber is more than 25 cm 2 ) according to specific needs by increasing the number of chambers to achieve photoelectrocatalytic flow reaction under different scales.

[0040] Application example

[0041] The above Figures 1 to 4 indicates a semiconductor heterogeneous photoelectrocatalytic flow reactor with two upper and lower reaction chambers. Further:

[0042] The two conductive glasses are FTO glasses. Each FTO glass has a size of 100 mm x 55 mm x 3 mm, and a square resistance of 10 ohms. Each FTO glass has a Mo-doped tungsten trioxide semiconductor catalyst with a width x length of 38 mm x 83 mm loaded in the central region. The specific preparation process is as follows: 1.49 mg of ammonium metatungstate, 30 mL of 3% mass concentration of hydrogen peroxide, and 1 mL of trifluoroacetic acid are added to 120 mL of deionized water and ultrasonically treated for 5 minutes; the obtained solution is added to a 300 mL Teflon liner, 2 mL of molybdenum acid ammonium (4 mM) is added, and stirred for 10 minutes; then, the FTO glass is added to the Teflon liner, and the Teflon liner is placed in an autoclave; the autoclave is placed in an oven at 160 degrees Celsius for 4 hours, and after cooling to room temperature, the FTO glass in the Teflon liner of the autoclave is taken out, and after burning in a muffle furnace at 500 degrees Celsius, the FTO glass photoanode 1 loaded with WO3 (Mo-doped) on the surface is obtained.

[0043] The anode substrate 2 is made of polytetrafluoroethylene (PTFE) with a size of 340 mm x 132 mm x 10 mm. The anode substrate 2 has two grooves (steps 23) with a length x width of 101 mm x 56 mm and a depth of 6 mm formed between the top surface of the anode substrate 2 and the area below the glass, for placing the FTO glass, and a 1 mm thick sealing ring 24 is placed below the glass. The center of the groove is a rectangular opening area with a length x width of 83 mm x 38 mm. Under this design, the length x width x height of each reaction chamber is 83 mm x 38 mm x 5 mm, respectively.

[0044] The anode current collector 3 is made of aluminum alloy, and the main body has a size of 340 mm x 132 mm x 10 mm. It is connected to the positive pole of the power supply and tightly contacts the anode substrate 2. There are two light transmission holes with the same shape as the FTO glass, which are located directly above the groove of the anode substrate 2.

[0045] The conductive frame 4 has a total of two, each with a size of 118 mm x 72 mm x 25 mm. There is a hollow area in the middle with a size of 83 mm x 38 mm, which ensures that the light generated by the light source module can pass through the light transmission holes of the anode current collector 3 and the hollow area of the conductive frame 4 to reach the surface of the FTO glass. The top of the conductive frame 4 has a flange with a width of 8.5 mm, and there are small holes that can pass through the bolts, which are used to achieve electrical contact with the anode current collector 3.

[0046] The cathode electrode 5 is made of titanium alloy with a size of 81 mm x 35 mm x 10 mm, and the surface is coated with a catalyst platinum (Pt). The back has two M8 threaded holes with a depth of 9 mm.

[0047] The cathode substrate 6 is a PTFE plate with a size of 340 mm x 132 mm x 15 mm. There are two cathode electrode grooves with a size of 81 mm x 36 mm x 10 mm on the top. The outermost annular groove 20 of the cathode substrate 6 has a width of 6.9 mm and a depth of 4.3 mm, which is used to place the O-ring. There is a transition flow channel groove 19 in the center of the cathode substrate 6 with a size of 38 mm x 38 mm x 1 mm, which serves as a transition flow channel between the two reaction chambers. The liquid inlet and outlet chambers on both sides of the cathode substrate 6 have the same size, with a size of 19 mm x 46 mm x 6 mm. The inlet and outlet grooves have the same size, with a size of 3 mm x 38 mm x 2 mm. The inlet and outlet have the same size, with an inner diameter of 2 mm. The first and second flow dividers have the same size, with a size of 18 mm x 45 mm x 5.5 mm. The filter paper 14 below the first flow divider 15 has a thickness of 0.1 mm and a pore size of 5 μm, which ensures uniform distribution of the fluid.

[0048] The cathode current collector 7 is an aluminum alloy plate with a size of 340 mm x 132 mm x 15 mm, which is connected to the negative pole of the power supply. The bolts pass through the holes of the cathode current collector 7 and the cathode substrate 6, and are tightened with the threaded holes on the back of the cathode electrode 5, which realizes the fastening of the cathode electrode 5 and the electrical contact between the cathode electrode 5 and the cathode current collector 7.

[0049] According to the Comsol simulation, the voltage on the copper tape of the photoanode 1 is set to 1.5 V (relative to the silver chloride reference electrode). Without considering mass transfer, the maximum current density on the surface of the photoanode 1 is 3.07 mA / cm 2 , and the difference between the highest and lowest current densities on the surface of the photoanode 1 is 0.24 mA / cm2 The surface photogenerated current density distribution of the resulting photoanode configuration can be well guaranteed.

[0050] The synthesis of 4,6-dimethoxy-2-methylsulfonyl-5-trifluoromethylpyrimidine was carried out using the above-described semiconductor heterogeneous photoelectrocatalytic flow reactor.

[0051]

[0052] A reaction bottle was charged with 1.01 g of 4,6-dimethyl-2-methylsulfonylpyrimidine, 7.63 g of potassium trifluoroacetate (CF3COOK), 7 mL of trifluoroacetic acid (TFA), and 70 mL of acetonitrile, and a stirring magnet was added to the reaction bottle.

[0053] The two photoanodes 1 prepared above were placed in the above-described semiconductor heterogeneous photoelectrocatalytic flow reactor. The reactor inlet and outlet, the reaction bottle, and the peristaltic pump were connected by FEP tubes to form a circulating flow path, and the flow rate of the peristaltic pump was set to 15 mL / min. At the same time, a light source with a wavelength of 395 nm and a power of 200 W was directed at the back of the photoanode, and the positive and negative poles of the power supply were connected to the reactor current collector by wires, and the voltage was set to 2 V, and the reaction was carried out at room temperature for 12 hours.

[0054] After the reaction was completed, the resulting solution was diluted with ethyl acetate, the pH was adjusted to neutral with sodium bicarbonate, and the organic phase was extracted with ethyl acetate, and the combined organic phase was concentrated under reduced pressure. The obtained residue was directly subjected to column chromatography separation, and the obtained white solid (0.93 g, 70%) was 4,6-dimethoxy-2-methylsulfonyl-5-trifluoromethylpyrimidine.

[0055] In addition, it should be understood that, after reading the above description of the present application, those skilled in the art can make various modifications or changes to the present application, and these equivalent forms also fall within the scope defined by the claims attached hereto.

Claims

1. A semiconductor heterogeneous photoelectrocatalytic flow reactor, characterized in that, include: A photoanode (1) loaded with a semiconductor catalyst is used to connect to the positive terminal of a power supply; An anode substrate (2) has a number of first through holes (8) that are the same as the number of photoelectric anodes (1) and can be completely covered by the photoelectric anodes (1) one by one; one side of the anode substrate (2) is sealed and connected to the photoelectric anode (1) at the position corresponding to the first through hole (8), and the opposite side is sealed and connected to the cathode substrate (6). The cathode substrate (6) has an inlet cavity (11) on its side near the anode substrate (2) and a cathode electrode (5) for connecting to the negative terminal of the power supply is embedded in the position corresponding to the first through hole (8). The space area where the first through hole (8) is located in each group of cathode electrodes (5) and photoanode (1) is a reaction chamber. The semiconductor catalyst loaded on the photoanode (1) is located in the reaction chamber. The cathode substrate (6) is provided with an outlet (10) communicating with the reaction chamber and an inlet channel groove (9) for connecting the inlet cavity (11) and the reaction chamber. The bottom of the inlet cavity (11) is provided with an inlet groove (12) with an inlet (13). The inlet cavity (11) is provided with a first distributor (15) with one end communicating with the inlet groove (12) and the other end opening towards the inlet channel groove (9). Filter paper (14) completely covering the inlet groove (12) is laid under the first distributor (15).

2. The semiconductor heterogeneous photoelectrocatalytic flow reactor according to claim 1, characterized in that, The photoanode (1) is a conductive glass with one side being a conductive surface loaded with a semiconductor catalyst and the other side being a non-conductive glass surface. A conductive tape is also attached to the conductive surface, and the conductive tape extends to the non-conductive glass surface.

3. The semiconductor heterogeneous photoelectrocatalytic flow reactor according to claim 2, characterized in that, The semiconductor heterogeneous photoelectrocatalytic flow reactor also includes an anode current collector (3) connected to the positive electrode of an external power source; The anode current collector (3) has an opening that allows the hollow conductive frame (4) for light transmission to pass through; One end of the conductive frame (4) is flanged for fixed connection with the anode current collector (3), and the other end passes through the anode current collector (3) to connect the conductive tape.

4. The semiconductor heterogeneous photoelectrocatalytic flow reactor according to claim 1, characterized in that, The semiconductor heterogeneous photoelectrocatalytic flow reactor also includes a cathode current collector (7) connected to the negative electrode of an external power supply; The cathode substrate (6) is provided with cathode grooves (16) for corresponding embedded cathode electrodes (5). A second through hole (17) is opened at the bottom of the cathode groove (16) for bolt fixing connection between the cathode current collector (7) and the cathode electrode (5), so as to realize the conductive path of cathode electrode (5)-bolt-cathode current collector (7)-power negative terminal.

5. The semiconductor heterogeneous photoelectrocatalytic flow reactor according to claim 1, characterized in that, The cathode substrate (6) is also provided with a liquid outlet cavity and an outlet flow channel groove (18) for connecting the liquid outlet cavity and the reaction chamber on the side close to the anode substrate (2); The outlet (10) is located in the outlet groove at the bottom of the outlet chamber; The liquid outlet chamber is equipped with a second diverter, one end of which is connected to the liquid outlet trough and the other end of which opens toward the outlet flow channel trough (18).

6. The semiconductor heterogeneous photoelectrocatalytic flow reactor according to claim 1, characterized in that, There are multiple photoanodes (1), and the reaction chambers are the same number as the photoanodes (1). The reaction chambers are connected in series and communicate with each other through a transition channel groove (19) opened on the cathode substrate (6).

7. The semiconductor heterogeneous photoelectrocatalytic flow reactor according to claim 1, characterized in that, The cathode substrate (6) is provided with an annular groove (20) on the side close to the anode substrate (2) for placing a sealing ring. The annular groove (20) surrounds the liquid inlet chamber (11), cathode electrode (5), outlet (10) and inlet flow channel groove (9) to achieve overall sealing of the reaction system.

8. The application of the semiconductor heterogeneous photoelectrocatalytic flow reactor according to any one of claims 1 to 7 in the field of continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis.

9. A continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis method, characterized in that, The semiconductor heterogeneous photoelectrocatalytic flow reactor according to any one of claims 1 to 7 is used, and the outlet (10) and the inlet (13) are connected by a circulation pump to form a circulation flow path, in which the reaction liquid circulates and reacts.

10. The continuous flow semiconductor heterogeneous photoelectrochemical organic synthesis method according to claim 9, characterized in that, The initial reaction solution contains 4,6-dimethyl-2-methanesulfonylpyrimidine, potassium trifluoroacetate, trifluoroacetic acid, and acetonitrile. The reaction product is 4,6-dimethoxy-2-methanesulfonyl-5-trifluoromethylpyrimidine. The semiconductor catalyst is Mo-doped tungsten trioxide. The photoelectric reaction conditions are: 390-400 nm wavelength light irradiation and voltage 1-3 V.

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