Continuous flow photochemical device and operation method thereof

Abstract

The invention provides a continuous flow photochemical device. The continuous flow photochemical device comprises a liquid and gas injection part, a four-way mixer, a photoreactor, a gas-liquid separator, a collecting part and a circulating part which are connected in sequence, the photoreactor comprises a mechanical shell, a light source module, a reaction hose and a temperature control module from outside to inside; all components of the photoreactor are wrapped by the mechanical shell; the light source module is fixed in the mechanical shell; the temperature control module comprises a hollow column pipe and an oil bath pipeline; the oil bath pipeline is spirally arranged in the column pipe; and the reaction hose is wound on the outer wall of the column tube. By isolating light source irradiation from oil bath temperature control, the problem of light source breakage caused by light passing through oil bath in the prior art is solved, and the utilization efficiency of light source energy is improved. The circulation part realizes a reaction path in which gas can be circulated, and the purposes of complete utilization and zero emission of the gas are achieved.

Description

Technical Field

[0001] The invention relates to the technical field of novel continuous flow chemistry, and in particular to a continuous flow photochemical device and an operating method thereof. Background Art

[0002] In recent years, photochemical reactions have been favored by universities, research institutes and industries at home and abroad. This is because compared with traditional chemical reactions, photochemical reactions use light energy to excite molecules to participate in chemical reactions, which has the advantages of high efficiency, energy saving and environmental protection. Photochemical reactions mainly involve excited molecules, which can produce a variety of active substances, and can achieve highly selective and efficient reactions through photosensitizers, catalysts and other means, often allowing the reaction to occur under mild conditions.

[0003] At present, photochemical reactions have broad application prospects in the fields of organic synthesis, drug synthesis, energy conversion, etc. On the other hand, continuous flow reactions have higher production efficiency and better heat and mass transfer performance than batch reactions. The reaction materials held in a continuous flow reactor are significantly less than those in a batch reaction, so the danger of some flammable and highly toxic reactions can be reduced, thereby reducing the potential safety hazards of the reaction. Continuous flow reactions generally have a smaller amplification effect and are easier to achieve expanded generation. At the same time, temperature control in photochemical reactions is crucial to maintaining reaction conditions and ensuring reaction efficiency. The prior art generally uses the reactor in an oil bath for temperature control, but this method will cause the light source to be damaged by the light passing through the oil bath, which reduces the efficiency of light source energy utilization. Summary of the invention

[0004] The technical problem to be solved by the present invention is how to improve the energy utilization efficiency of the light source and achieve zero emission of gas raw materials in a continuous flow photochemical reaction based on gas-liquid mixing.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] The present invention provides a continuous flow photochemical device, comprising: a liquid and gas injection part, a four-way mixer, a photoreactor, a gas-liquid separator, a collection part and a circulation part connected in sequence;

[0007] The photoreactor includes a mechanical shell, a light source module, a reaction hose and a temperature control module from the outside to the inside; the mechanical shell wraps all the components of the photoreactor; the light source module is fixed inside the mechanical shell; the temperature control module includes an internal hollow column tube and an oil bath pipeline; the oil bath pipeline is spirally built into the column tube; the reaction hose is wrapped around the outer wall of the column tube.

[0008] Furthermore, the liquid push injection unit includes a liquid storage bottle and a liquid injection pump which are connected in sequence.

[0009] The gas push injection unit comprises a gas supply bottle, a pressure reducing valve, a gas flow meter and a one-way valve which are connected in sequence.

[0010] Preferably, the reaction hose is made of 1 / 16 inch Teflon polytetrafluoroethylene tube.

[0011] Preferably, the light source module uses a 450-470nm blue light LED to irradiate the column tube.

[0012] Preferably, the column tube and the oil bath pipe are both made of 6061 aluminum alloy.

[0013] The input port of the gas-liquid separator is connected to the photoreactor, and the output port is connected to the collecting part and the circulating part; a TLC spot plate is arranged at the input port of the gas-liquid separator.

[0014] The collecting part includes a gas collecting bottle and a circulating material bottle; the gas collecting bottle is connected to the gas-liquid separator and is used to collect the residual gas separated after the photoreactor; the circulating material bottle is connected to the gas-liquid separator and is used to collect the solution separated after the photoreactor.

[0015] The circulation part includes an air outlet path and a liquid outlet path, and both the air outlet path and the liquid outlet path are connected to the output port of the gas-liquid separator; the air outlet path includes a gas collecting bottle, a gas injection pump, a gas flow meter, a one-way valve and a four-way mixer connected in sequence; the liquid outlet path includes a circulating material bottle, a liquid injection pump and a four-way mixer connected in sequence.

[0016] The present invention also provides an operating method based on the above-mentioned continuous flow photochemical device, characterized in that the operating method is specifically as follows:

[0017] The solid raw materials and liquid solvent are mixed into a solution and placed in a liquid storage bottle. Stirring ensures that the solution is clear and does not cause clogging of the pipeline. The solution flows in the liquid pipe through a liquid injection pump and is transported to the liquid input port of the four-way mixer.

[0018] The gas raw material in the gas supply bottle is transported to the gas input port of the four-way mixer through the pressure reducing valve, gas pipe, gas flow meter and one-way valve;

[0019] The solution and gas are uniformly and fully mixed in the four-way mixer and then transported to the reaction hose in the photoreactor through the mixing tube for chemical reaction; the photoreactor turns on the light source module and the temperature control module, the light source module provides a light source, and irradiates the reaction hose from the outside to make the reactants enter an excited state; the temperature control module controls the temperature of the reaction hose wrapped around the outer wall of the column tube through the spiral circulating oil bath pipeline built into the column tube; the mixture of the solution and the gas flows in the reaction hose around the column tube, and a continuous flow photochemical reaction is carried out through external light source irradiation and temperature control inside the column tube;

[0020] The outlet of the photoreactor is connected to the gas-liquid separator, and an air outlet pipe is arranged at the upper end of the gas-liquid separator, and a liquid outlet pipe is arranged at the bottom; the solution raw materials are detected by observing through the TLC spot plate at the input port of the gas-liquid separator, and if the raw materials in the solution are completely converted, the reaction solution is transported to the circulating material bottle for collection, and the gas is transported to the gas collecting bottle for collection; if the raw materials in the solution are not completely converted, the reaction system is subjected to gas-liquid separation at the gas-liquid separator, and the gas passes through the air outlet pipe, the gas collecting bottle, the gas injection pump, the gas flow meter, and the one-way valve and returns to the four-way mixer; the unreacted solution mixture is returned to the circulating material bottle for storage after passing through the liquid outlet pipe; when the liquid injection pump has transported the initial material, the solution stored in the circulating material bottle is re-injected into the four-way mixer to be fully mixed with the gas, and then transported to the photoreactor for reaction; this cycle is repeated until it is detected by the TLC spot plate that the raw materials in the solution are completely converted, and the product is collected through the circulating material bottle.

[0021] The advantages of the present invention are:

[0022] (1) By setting up a built-in wall heat exchange method in the device based on the gas-liquid mixed continuous flow photoreaction, the oil bath temperature control is separated from the light source utilization, avoiding the light source loss problem caused by the light passing through the oil bath, and improving the utilization efficiency of the light source energy. At the same time, the photoreaction tube is wound on a jacketed column tube with a temperature control system, which not only increases the illumination area, but also improves the uniformity of temperature control for continuous flow reactions.

[0023] (2) By setting up a circulation section in the device based on the continuous flow photochemical reaction of gas-liquid mixing, a cyclic reaction path for the continuous flow photochemical reaction is constructed, so that the gas raw materials can be fully utilized and the goal of zero gas emission is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic structural diagram of a continuous flow photochemical device according to Example 1 of the present invention;

[0025] Figure 2 This is a schematic diagram of the exterior of a photoreactor column tube of a continuous flow photochemical device according to Example 1 of the present invention;

[0026] Figure 3 This is a schematic diagram of the internal cross-section of a photoreactor column tube of a continuous flow photochemical device according to Example 1 of the present invention;

[0027] Figure 4 The target product of a continuous flow photochemical reaction according to Example 1 of the present invention is 1 H NMR nuclear magnetic spectrum;

[0028] Figure 5 The target product of a continuous flow photochemical reaction according to Example 1 of the present invention is 13C NMR nuclear magnetic resonance spectrum.

[0029] in:

[0030] 1-gas supply bottle; 2-gas pipe; 3-liquid pipe; 4-liquid storage bottle; 5-liquid injection pump; 6-pressure reducing valve; 7-gas flowmeter; 8-check valve I; 9-four-way mixer; 10-mixing tube; 11-photoreactor; 12-gas-liquid separator; 13-gas outlet pipe; 14-gas collecting bottle; 15-gas injection pump; 16-gas flowmeter; 17-check valve II; 18-liquid outlet pipe; 19-circulating material bottle; 111-column tube; 112-reaction hose; 113-oil bath pipeline. DETAILED DESCRIPTION

[0031] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example 1

[0033] Embodiment 1 of the present invention discloses a continuous flow photochemical device, such as Figure 1 As shown, it includes: liquid and gas push injection part, four-way mixer, photoreactor, gas-liquid separator, collection part and circulation part connected in sequence. The liquid push injection part includes a liquid storage bottle 4, a liquid injection pump 5 and a liquid pipe 3 connected in sequence. The gas push injection part includes a gas supply bottle 1, a gas pipe 2, a pressure reducing valve 6, a gas flow meter 7, and a one-way valve Ⅰ8 connected in sequence; the mixture output port is connected to the photoreactor 11;

[0034] Furthermore, the solid raw materials and liquid solvent are mixed into a solution and placed in a liquid storage bottle 4. The solution is stirred to ensure that the solution is clear and does not clog the pipeline. The solution flows in the liquid pipe 3 through the liquid injection pump 5 and is transported to the liquid input port of the four-way mixer 9. The solution and the gas are uniformly and fully mixed in the four-way mixer 9 and then transported to the photoreactor 11 through the mixing tube 10 for chemical reaction.

[0035] The photoreactor includes a mechanical shell, a light source module, a reaction hose and a temperature control module from the outside to the inside; the mechanical shell wraps all components of the photoreactor; the light source module is fixed inside the mechanical shell; Figure 3 As shown, the temperature control module includes a hollow column tube and an oil bath pipeline; the oil bath pipeline is spirally built into the column tube; Figure 2As shown, the reaction hose is wound around the outer wall of the column tube. The reaction hose is made of 1 / 16 inch Teflon polytetrafluoroethylene tube; the light source module adopts a 450-470nm blue light LED light source; the column tube and the oil bath pipeline are made of 6061 aluminum alloy. The photoreactor 11 performs a chemical reaction on the system in the reaction hose. The separation part adopts a gas-liquid separator; the input port of the gas-liquid separator 12 is connected to the above-mentioned reaction hose, and the output port is connected to the circulation part. The collection part includes a gas collection bottle 14 and a circulation material bottle 19; the gas collection bottle 14 collects the remaining gas; the circulation material bottle 19 collects the reaction solution. The circulation part includes: an outlet gas path 13 and a liquid outlet path 18; the outlet gas path 13 passes through the gas collection bottle 14, the gas injection pump 15, the gas flowmeter 16 and the one-way valve II 17, and is connected to the input port of the four-way mixer 9; the liquid outlet path 18 passes through the circulation material bottle 19 and the liquid injection pump 5 and is connected to the input port of the four-way mixer 9.

[0036] Furthermore, in actual operation, Figure 1 As shown, the reaction solid raw materials and liquid raw materials are prepared into a solution and placed in a liquid storage bottle 4. By stirring, the solution is ensured to be clear and will not cause the pipeline to be blocked. Preferably, a suction filter head can also be installed at the inlet of the hose. The solution is transported in the liquid pipe 3 by the liquid injection pump 5 and enters the four-way mixer 9; the liquid injection pump 5 can set the liquid flow rate, which can make the liquid flow evenly in the pipeline, which is simple, convenient and easy to operate. The gas raw material in the gas supply bottle 1 passes through the pressure reducing valve 6, the gas pipe 2 and the gas flow meter 7, and the one-way valve I8, and enters the four-way mixer 9; the gas flow meter 7 can control the gas flow rate to match the liquid flow rate; the one-way valve I8 can prevent the liquid from flowing back into the gas path.

[0037] Further, the four-way mixer 9 connects the gas tube 2 and the liquid tube 3, where the gas and liquid are evenly and fully mixed. The gas raw material is evenly mixed with the solution through the four-way mixer 9 and then transported to the photoreactor 11 through the mixing tube 10 for chemical reaction; the photoreactor turns on the light source module and the temperature control module, and the light source module provides a 450-470nm blue light LED to irradiate the reaction hose from the outside, so that the reactant enters an excited state; the temperature control module controls the temperature of the reaction hose wrapped around the outer wall of the column tube through the spiral circulating oil bath pipeline built into the column tube; the mixture of the solution and the gas flows around the column tube in the reaction hose, and a continuous flow photochemical reaction is carried out through external light source irradiation and temperature control inside the column tube; through the above method, the light source irradiation is isolated from the temperature control, avoiding the problem of light source loss caused by light passing through the oil bath, and improving the utilization efficiency of the light source energy. At the same time, the light reaction tube is wound around the jacketed column tube with a temperature control system, which not only increases the illumination area, but also improves the uniformity of temperature control for continuous flow reactions.

[0038] The outlet of the photoreactor is connected to the gas-liquid separator 12. An outlet pipe 13 is arranged at the upper end of the gas-liquid separator 12, a liquid outlet pipe 18 is arranged at the bottom of the gas-liquid separator 12, and a TLC spot plate is arranged at the input port of the gas-liquid separator 12. Through the TLC spot plate observation, the solution raw materials are detected. If the raw materials in the solution are completely converted, the reaction solution is transported to the circulating material bottle 19 for collection, and the gas is transported to the gas collecting bottle 14 for collection; if the raw materials in the solution are not completely converted, the reaction system is separated into gas and liquid at the gas-liquid separator 12 and transported to the circulation part, that is, the gas returns to the four-way mixer 9 after passing through the outlet pipe 13, the gas collecting bottle 14, the gas injection pump 15, the gas flow meter 16, and the one-way valve II 17, and the end of the outlet pipe 13 is connected to the four-way mixer 9; the gas injection pump 15 can well control the flow rate of the unreacted gas, better participate in the subsequent reaction, and also achieve the purpose of zero gas emission. The gas flow meter 16 can more intuitively observe the cumulative flow and instantaneous flow. At the same time, the unreacted solution, raw materials and target products are returned to the circulating material bottle 19 for storage after passing through the liquid outlet pipe 18; when the liquid injection pump 5 has delivered the original material, the solution stored in the circulating material bottle 19 is re-injected into the four-way mixer 9 to be fully mixed with the gas, and then delivered to the photoreactor for reaction again. This cycle is repeated until the raw materials in the solution are completely converted through TLC spot plate observation, and the product is collected through the circulating material bottle 19.

[0039] Preferably, in this embodiment, the raw material solution is limited, while the supply of gas can be unlimited. The gas raw material always circulates in the device until the solution raw material is completely converted, the chemical reaction stops, and the solution product is collected for subsequent operations. Therefore, zero emission of reaction gas can be achieved.

[0040] Preferably, in the above-mentioned cyclic reaction, the flow rate can be set, the liquid flow rate is controlled by the liquid injection pump 5, and the gas flow rate is controlled by the gas injection pump 15, so as to achieve the material ratio designed in the experiment.

[0041] Preferably, when all the solution raw materials in this experiment have reacted completely, the gas supply is stopped, and the remaining gas in the system is transported to the gas collecting bottle 14 for collection, thereby further achieving the purpose of zero gas emission.

[0042] Preferably, the gas-liquid separator 12 described in the embodiment of the present invention can accurately control the collection amount or circulation amount of the solution when the solution product is collected or the solution is circulated again through the liquid outlet path, thereby ensuring that a certain volume of solution is always maintained in the gas-liquid separator to avoid gas leakage when the solution product is collected.

[0043] Based on the above device and its operation mode, the embodiment of the present invention also discloses a specific gas-liquid mixed continuous flow photochemical reaction experiment to verify the operation mode and effect of the device. The chemical reaction experiment is as follows:

[0044] The raw material 3-methylbenzoic acid (0.3 g) and the photocatalyst (Ir[dF(CF3)ppy]2(dtbpy))PF6 (14 mg, 0.5 mol%) were loaded into the liquid storage bottle 4 (25.0 mL) equipped with a perforated rubber stopper and a magnetic stirring bar, and then anhydrous MeCN (5 mL), DIPEA (2 mL, 5.0 equivalents) and diethylamine (2.3 mL, 10.0 equivalents) were added to the liquid storage bottle 4 through a syringe, and the solution was stirred until clear by the magnetic stirring bar. The pipette of the injection pump 5 was placed in the hole of the rubber stopper. After preparation, the gas supply bottle 1 and the pressure reducing valve 6 were opened, and the gas flow meter 7 was used to adjust the gas flow to 1.5 SCCM, and the SF6 gas entered the mixer 9 through the one-way valve Ⅰ8. At the same time, the liquid outlet speed was adjusted to 0.02 mL / min, and the injection pump 5 was started, and it entered the four-way mixer 9 through the liquid pipe 3. The photoreactor 11 is turned on, and the gas-liquid mixture enters the photoreactor 11 through the mixing tube 10 to perform a continuous flow reaction. The gas-liquid mixture after the reaction is separated into gas and liquid in the gas-liquid separator 12.

[0045] Further, after all the reaction solution was injected, the reaction was closed by TLC spot plate observation to confirm that the raw materials in the solution had been completely converted, and the reaction solution was separated from the circulating material bottle 19. The reaction solution was quenched by adding a saturated NH4Cl solution, and extracted three times with ethyl acetate, the organic layers were combined, the solvent was removed under vacuum, and the residue was purified by silica gel flash column chromatography (petroleum ether / ethyl acetate=10 / 1) to obtain a yellow liquid product N,N-diethyl-3-methylbenzamide (266.7 mg, 63%).

[0046] Specifically, the reaction equation is:

[0047]

[0048] The target product N,N-diethyl-3-methylbenzamide (N,N-diethyl-3-methylbenzamide) NMR data are as follows: Figure 3 and Figure 4 As shown,

[0049] 1 H NMR (600MHz, CDCl3) δ7.27-7.25(m,1H),7.19-7.13(m,3H),3.54(s,2H),3.25(s,2H),2.36(s,3H),1.24(s,3H),1.09(s,3H).

[0050] 13 C NMR (150MHz, CDCl3) δ171.5,138.2,137.3,129.8,128.2,126.9,123.2,43.3,39.2,21.4,14.2,12.9.

[0051] In particular, in order to further prove the effect of the present invention on improving the utilization rate of light sources, as a comparative experiment, the photoreactor was directly placed in a 25°C oil bath for temperature control, and the above experiment used the same amount of raw materials, the same operating steps, and irradiated for the same time, the same light source and the same light source distance. After post-reaction treatment, the product N,N-diethyl-3-methylbenzamide (155.9 mg, 37%) was obtained. Compared with the temperature control method inside the column tube, the yield decreased significantly. It shows that by optimizing the structure of the temperature control module of the photoreactor, the utilization rate of the light source is improved by avoiding the loss of the light source.

[0052] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A continuous flow photochemical device, characterized in that: It includes the following parts connected in sequence: liquid and gas injection part, four-way mixer, photoreactor, gas-liquid separator, collection part and circulation part; The photoreactor comprises, from outside to inside, a mechanical housing, a light source module, a reaction hose and a temperature control module; The mechanical shell wraps all components of the photoreactor; the light source module is fixed inside the mechanical shell; the temperature control module includes an internal hollow column tube and an oil bath pipeline; the oil bath pipeline is spirally built into the column tube; and the reaction hose is wound around the outer wall of the column tube.

2. A continuous flow photochemical device according to claim 1, characterized in that: The liquid push injection unit comprises a liquid storage bottle and a liquid injection pump which are connected in sequence.

3. A continuous flow photochemical device according to claim 1, characterized in that: The gas push injection unit comprises a gas supply bottle, a pressure reducing valve, a gas flow meter and a one-way valve which are connected in sequence.

4. A continuous flow photochemical device according to claim 1, characterized in that: The reaction hose is made of 1 / 16 inch Teflon polytetrafluoroethylene tube.

5. A continuous flow photochemical device according to claim 1, characterized in that: The light source module uses a 450-470nm blue light LED to irradiate the column tube.

6. A continuous flow photochemical device according to claim 1, characterized in that: The column tube and the oil bath pipe are both made of 6061 aluminum alloy.

7. A continuous flow photochemical device according to claim 1, characterized in that: The input port of the gas-liquid separator is connected to the photoreactor, and the output port is connected to the collecting part and the circulating part; a TLC spot plate is arranged at the input port of the gas-liquid separator.

8. A continuous flow photochemical device according to claim 1, characterized in that: The collecting part includes a gas collecting bottle and a circulating material bottle; the gas collecting bottle is connected to the gas-liquid separator and is used to collect the residual gas separated after the photoreactor; the circulating material bottle is connected to the gas-liquid separator and is used to collect the solution separated after the photoreactor.

9. A continuous flow photochemical device according to claim 1, characterized in that: The circulation part includes an air outlet path and a liquid outlet path, and both the air outlet path and the liquid outlet path are connected to the output port of the gas-liquid separator; the air outlet path includes a gas collecting bottle, a gas injection pump, a gas flow meter, a one-way valve and a four-way mixer connected in sequence; the liquid outlet path includes a circulating material bottle, a liquid injection pump and a four-way mixer connected in sequence.

10. A method for operating a continuous flow photochemical device according to any one of claims 1 to 9, characterized in that: The operation method is as follows: The solid raw materials and liquid solvent are mixed into a solution and placed in a liquid storage bottle. Stirring ensures that the solution is clear and does not cause clogging of the pipeline. The solution flows in the liquid pipe through a liquid injection pump and is transported to the liquid input port of the four-way mixer. The gas raw material in the gas supply bottle is transported to the gas input port of the four-way mixer through the pressure reducing valve, gas pipe, gas flow meter and one-way valve; The solution and gas are uniformly and fully mixed in the four-way mixer and then transported to the reaction hose in the photoreactor through the mixing tube for chemical reaction; the photoreactor turns on the light source module and the temperature control module, the light source module provides a light source to irradiate the reaction hose from the outside, so that the reactants enter an excited state; the temperature control module controls the temperature of the reaction hose wrapped around the outer wall of the column tube through the spiral circulating oil bath pipeline built into the column tube; the mixture of the solution and the gas flows in the reaction hose around the column tube, and performs a continuous flow photochemical reaction under the irradiation of the external light source and the temperature control inside the column tube; The outlet of the photoreactor is connected to the gas-liquid separator, and an air outlet pipe is arranged at the upper end of the gas-liquid separator, and a liquid outlet pipe is arranged at the bottom; the solution raw materials are detected by observing through the TLC spot plate at the input port of the gas-liquid separator, and if the raw materials in the solution are completely converted, the reaction solution is transported to the circulating material bottle for collection, and the gas is transported to the gas collecting bottle for collection; if the raw materials in the solution are not completely converted, the reaction system is subjected to gas-liquid separation at the gas-liquid separator, and the gas passes through the air outlet pipe, the gas collecting bottle, the gas injection pump, the gas flow meter, and the one-way valve and returns to the four-way mixer; the unreacted solution mixture is returned to the circulating material bottle for storage after passing through the liquid outlet pipe; when the liquid injection pump has transported the initial material, the solution stored in the circulating material bottle is re-injected into the four-way mixer to be fully mixed with the gas, and then transported to the photoreactor for reaction; this cycle is repeated until it is detected by the TLC spot plate that the raw materials in the solution are completely converted, and the product is collected through the circulating material bottle.

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