Microtube reactor with photothermal conversion function and preparation method and application thereof

Abstract

The invention relates to a microtube reactor with a photothermal conversion function and a preparation method and application thereof, and belongs to the technical field of photochemical microreactors. The preparation method comprises the following steps: S1, designing a model of the microtube reactor by using 3ds Max software; s2, a 3D printer is used for printing, and a microtube reactor is obtained; the microtube reactor is made of photosensitive resin and a photo-thermal agent; the mass fraction of the photo-thermal agent is 0.01 wt% to 5.00 wt%; and S3, cleaning and curing the microtube reactor to obtain the microtube reactor with the photo-thermal conversion function. The microtube reactor which has a photothermal conversion function and can be applied to different heating reactions is prepared by combining the high-strength high-temperature-resistant photosensitive resin doped with the photothermal agent with a 3D printing technology, so that the microtube reactor has important significance in expanding the application range of the microreactor and saving energy.

Description

Technical Field

[0001] The present invention belongs to the technical field of photochemical microreactors, and in particular relates to a micro-tube reactor with a photothermal conversion function, a preparation method and an application thereof. Background Art

[0002] A microreactor is a microfluidic technology tool that allows microchannels, microcavities, etc. to flexibly and accurately control reactants with characteristic dimensions of microscale (≤1mm). Compared with traditional intermittent reactors (such as reaction bottles and reactors), microreactors can quickly mix, quickly exchange heat, and efficiently carry out continuous multi-step reactions. They have good reaction selectivity and reproducibility, are easy to scale up, have better safety, and allow more extreme reaction conditions. The characteristics of rapid mixing and rapid heat dissipation of microreactors can provide high selectivity for target products, which plays a great role in endothermic or exothermic reactions. As a type of microreactor, the continuous flow microtubule reactor has shown unique synthetic advantages in the fields of organic synthesis, polymer synthesis, analytical chemistry, biomedicine, etc. in recent decades. The development of microtubule reactors is of great significance for improving the reaction rate and yield of chemical reactions, and is the development trend of industrial large-scale production. However, the current photochemical microreactors are only suitable for reaction systems that act with light, and a large number of chemical reactions that are insensitive to light are not applicable, such as many heating reactions.

[0003] In chemical reactions, heating is a very common reaction condition. Common heating methods include water baths, oil baths, air baths, etc., which require continuous heating of a large amount of heat transfer medium to heat the reactants and promote the reaction. However, a large amount of energy will be consumed in this process. As a clean energy source, light energy (solar energy) has flexible spatiotemporal controllability and remote controllability. Among them, photothermal conversion is the most direct, simple and efficient way to utilize light. Therefore, it is of great significance to develop a microtube reactor with photothermal conversion function. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a microtube reactor with photothermal conversion function and its preparation method and application. A microtube reactor with photothermal conversion function that can be applied to different heating reactions is prepared by combining a high-strength, high-temperature resistant photosensitive resin doped with a photothermal agent with 3D printing technology. This is of great significance for expanding the application range of the microreactor and saving energy.

[0005] The first object of the present invention is to provide a method for preparing a micro-tube reactor having a photothermal conversion function, comprising the following steps:

[0006] S1. Using 3ds Max software to design a model of a microtubular reactor; the model includes a spiral microtubular reactor body; a microchannel is formed in the microtubular reactor body; and a liquid inlet and a liquid outlet connected to the microchannel are respectively formed at two ends of the microtubular reactor along the axial direction;

[0007] S2. Printing with a 3D printer to obtain a micro-tube reactor; the material of the micro-tube reactor includes a photosensitive resin and a photothermal agent; the mass fraction of the photothermal agent is 0.01wt%-5.00wt%;

[0008] S3, cleaning and curing the micro-tube reactor to obtain the micro-tube reactor with light-to-heat conversion function.

[0009] In one embodiment of the present invention, in S1, the inner diameter of the microchannel is 0.7 mm-1 mm, and the cross-sectional shape is selected from circular, elliptical, triangular, square or polygonal.

[0010] In one embodiment of the present invention, in S1, the spiral radius of the micro-tube reactor body is 10 mm-50 mm, the spiral density is 3.5 mm / turn-6 mm / turn, and the tube wall thickness is 0.5 mm-2 mm.

[0011] In one embodiment of the present invention, in S2, the 3D printer is selected from a digital light processing (DLP) 3D printer or a liquid crystal photomask (LCD) 3D printer.

[0012] In one embodiment of the present invention, in S2, the layer printing accuracy of the 3D printer is 0.025mm-0.05mm.

[0013] In one embodiment of the present invention, in S2, the photosensitive resin is selected from one or more of polyurethane acrylate, epoxy resin, polyimide (PI), polyetherimide (PEI), polyetheretherketone (PEEK) and polyphenylene sulfide (PPS); the photosensitive resin has high strength and is resistant to high temperatures.

[0014] In one embodiment of the present invention, in S2, the photothermal agent is selected from one or more of cresol, phthalocyanine, graphene, carbon black, polyaniline, polypyrrole, polythiophene, polydopamine, lignin, gold nanoparticles, copper sulfide particles, carbon dots and indocyanine green.

[0015] In one embodiment of the present invention, in S3, the cleaning is performed by using ethanol; the curing is performed by using an ultraviolet lamp with a power of 25W-40W for 20min-60min, and the wavelength of the ultraviolet lamp is 355nm-405nm.

[0016] The second object of the present invention is to provide a micro-tube reactor with photothermal conversion function prepared by the method described above.

[0017] In one embodiment of the present invention, a plurality of micro-tube reactors with light-to-heat conversion function are connected in series, and then photosensitive resin is used for curing at the connection points to meet different usage requirements.

[0018] The third object of the present invention is to provide an application of the micro-tube reactor with light-to-heat conversion function in a heating reaction.

[0019] The technical solution of the present invention has the following advantages over the prior art:

[0020] (1) The preparation method described in the present invention applies a high-strength, high-temperature resistant photosensitive resin doped with a photothermal agent to a microtube reactor, giving the microtube reactor the function of photothermal conversion, which can partially or completely convert the light energy irradiated on the surface of the microtube into thermal energy. Combined with the advantage of rapid heat exchange of the microtube reactor, the temperature of the microtube reactor can be controlled by light. Compared with traditional heating methods (water bath, oil bath, air bath, etc.), it can effectively reduce the energy loss and environmental pollution caused by direct heating.

[0021] (2) The preparation method described in the present invention directly realizes the construction from digital models to physical objects through 3D printing technology, has the ability to "control shape and properties" and directly form high-precision complex parts in one step. It does not require complex tools and machines, and can produce microfluidic devices, which is cheaper, faster and easier than traditional microfluidic preparation.

[0022] (3) The micro-tube reactor with photothermal conversion function described in the present invention can convert light energy into heat energy under illumination, and is suitable for various heating reactions, such as polymer synthesis, small molecule synthesis, nanoparticle preparation, etc., which greatly broadens the types of chemical reactions occurring in the photoreactor and has stronger universality. The use of the micro-tube reactor can make fluid mixing reactions in the chemical industry more efficient, safe, and environmentally friendly, which is of great significance to the development of the chemical industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to make the content of the present invention more clearly understood, the present invention is further described in detail below according to specific embodiments of the present invention in conjunction with the accompanying drawings, wherein:

[0024] Figure 1 This is a schematic diagram of a micro-tube reactor designed by 3ds Max software in Example 1 of the present invention;

[0025] Figure 2 This is a photothermal conversion performance diagram of the microtube reactor under near-infrared light irradiation in Example 1 of the present invention. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with specific embodiments so that those skilled in the art can better understand the present invention and implement it. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. It should be understood that the specific embodiments are only used to explain the present invention, but the embodiments are not intended to limit the present invention.

[0027] In the present invention, unless otherwise explained, technical and scientific terms used in the present invention have the same meanings as commonly understood by those skilled in the art to which the present invention belongs.

[0028] In the present invention, unless otherwise stated, the term "and / or" used in the present invention includes any and all combinations of one or more of the associated listed items.

[0029] In the present invention, unless otherwise stated, the experimental methods used in the embodiments of the present invention are conventional methods unless otherwise stated, and the materials, reagents, etc. used are all commercially available unless otherwise stated.

[0030] In the present invention, unless otherwise specified, the photosensitive resin used in the embodiments of the present invention is purchased from Xiaogan Yisheng New Materials Co., Ltd., and the model is LCD high temperature resistant resin pink (the main component is polyurethane acrylate).

[0031] Example 1

[0032] The micro-tube reactor with light-to-heat conversion function and the preparation method thereof of the present invention specifically include the following steps:

[0033] S1. Adding a photothermal agent, oxadiazine cyanine, into a photosensitive resin, stirring and mixing, and obtaining a target resin; wherein the mass fractions of the photothermal agent, oxadiazine cyanine, are 0.00wt%, 0.05wt%, 0.10wt%, and 0.20wt% respectively;

[0034] S2. Use 3ds Max software to design a model of a microtube reactor; the model includes a spiral microtube reactor body; a microchannel is formed in the microtube reactor body; a liquid inlet and a liquid outlet are formed at both ends of the microtube reactor along the axial direction, which are connected to the microchannel; the inner diameter of the microchannel is 1mm, and the cross-sectional shape is circular. The spiral radius of the microtube reactor body is 20mm, the spiral density is 5mm / turn, a total of 6.5 turns, and the tube wall thickness is 0.8mm ( Figure 1 );

[0035] S3, using a liquid crystal mask (LCD) 3D printer to perform 3D printing with a layer printing accuracy of 0.05 mm to obtain a microtube reactor;

[0036] S4. After printing is completed, remove the microtube reactor from the work platform, clean the surface of the microtube reactor with ethanol, connect the microtube reactor to the pump, and flush the microchannel with ethanol until the outflowing ethanol is clear and transparent, ensuring that there is no resin residue in the channel; then place it in a UV curing box with a power of 25W (wavelength of 405nm) for curing for 60 minutes, place it in a 50℃ oven for 30 minutes, and place it in a 150℃ oven for 30 minutes to obtain a microtube reactor with photothermal conversion function.

[0037] The microtube reactor with photothermal conversion function was placed in a cylindrical light-shielding cooling cylinder with a near-infrared LED light strip pasted inside. The photothermal conversion performance of the microtube reactor with photothermal conversion function prepared with different mass fractions of the photothermal agent crotonyl cyanine was measured using an infrared thermal imager. The distance between the light source and the microtube reactor with photothermal conversion function was about 2 cm. The infrared thermal imager was used to record the temperature change on the surface of the microtube reactor with photothermal conversion function. The detection distance was about 10 cm. The photothermal conversion time-temperature curve was obtained by measuring the temperature change at least three different positions of the same sample and taking the average value. The results are shown in Figure 2 From Figure 2 It can be seen that the micro-tube reactor with photothermal conversion function prepared by pure photosensitive resin (0.00wt%) finally reaches an equilibrium temperature of 30°C under a near-infrared light source; the micro-tube reactor with photothermal conversion function prepared by resin with 0.05wt% of ketocyanine dye content finally reaches an equilibrium temperature of 70°C, the micro-tube reactor with photothermal conversion function prepared by resin with 0.10wt% of ketocyanine dye content finally reaches an equilibrium temperature of 80°C, and the micro-tube reactor with photothermal conversion function prepared by resin with 0.20wt% of ketocyanine dye content finally reaches an equilibrium temperature of 100°C. This shows that the photothermal performance of the micro-tube reactor with photothermal conversion function is good, which can cover the temperature range of most heating reactions and meet most application scenarios.

[0038] Example 2

[0039] The micro-tube reactor with light-to-heat conversion function and the preparation method thereof of the present invention specifically include the following steps:

[0040] S1. Adding a photothermal agent, oxadiazine cyanine, into a photosensitive resin, and stirring and mixing to obtain a target resin; wherein the mass fraction of the photothermal agent, oxadiazine cyanine, is 0.05wt%;

[0041] S2. Use 3ds Max software to design a model of a microtube reactor; the model includes a spiral microtube reactor body; a microchannel is formed in the microtube reactor body; a liquid inlet and a liquid outlet connected to the microchannel are formed at both ends of the microtube reactor along the axial direction; the inner diameter of the microchannel is 1mm, and the cross-sectional shape is circular. The spiral radius of the microtube reactor body is 20mm, the spiral density is 5mm / turn, a total of 13.5 turns, and the tube wall thickness is 0.8mm;

[0042] S3, using a liquid crystal mask (LCD) 3D printer to perform 3D printing with a layer printing accuracy of 0.05 mm to obtain a microtube reactor;

[0043] S4. After printing is completed, remove the microtube reactor from the work platform, clean the surface of the microtube reactor with ethanol, connect the microtube reactor to the pump, and rinse the microchannel with ethanol until the ethanol flowing out is clear and transparent, ensuring that there is no resin residue in the channel; then place it in a UV curing box with a power of 25W (wavelength of 405nm) for curing for 60min, place it in a 50℃ oven for 30min, and place it in a 150℃ oven for 30min; connect 4 prepared microtube reactors in series, and use photosensitive resin to cure at the interface to obtain a microtube reactor with photothermal conversion function.

[0044] The micro-tube reactor with photothermal conversion function is placed in a cylindrical light-shielding cooling cylinder with a near-infrared LED light bar pasted inside. The synthesis of polymethyl methacrylate (PMMA) is taken as an example by using the reversible-inactivation fragmentation chain transfer (RAFT) free radical polymerization reaction. The reaction conditions are heating polymerization (70°C). It is proved that the micro-tube reactor with photothermal conversion function can be used for chemical reactions that require heating conditions, such as polymer synthesis, small molecule synthesis, nanoparticle preparation, etc. Methyl methacrylate (MMA) is used as a monomer, 2-cyano-2-propylbenzodisulfide (CPDB) is used as a RAFT agent, azobisisobutyronitrile (AIBN) is used as an initiator, and toluene is used as a solvent. Take the polymerization molar ratio of [MMA]0 / [CPDB]0 / [AIBN]0=400 / 2 / 1 as an example. MMA (2.16 g, 21.6 mmol), CPDB (0.0239 g, 0.108 mmol) and toluene (4.8 mL) were mixed in a 10 mL ampoule, a magnetic bar was added, and a uniform solution was formed by stirring. Argon gas was bubbled to remove the oxygen dissolved therein, and then the solution was sealed with a sealing film. The near-infrared light source was turned on, and the temperature of the micro-tube reactor with photothermal conversion function quickly rose to 70°C. Subsequently, the metering pump was turned on, and the reaction solution was pumped into the micro-tube reactor with photothermal conversion function at a flow rate of 0.5 mL / min. The polymerization reaction occurred when the reaction solution flowed through the tube. After reaching the preset time, the reaction solution was collected at the outlet of the microtube, the polymer stock solution was diluted with tetrahydrofuran and precipitated in an appropriate amount of petroleum ether; the filter cake was filtered and vacuum dried at 40°C overnight to obtain the target polymer PMMA. The polymerization conditions were: R = [MMA] 0 / [CPDB] 0 / [AIBN] 0, toluene as solvent, polymerization temperature (microtube temperature) = 71 ± 3°C, a Monomer conversion (Conv.) 1 H NMR calculations, b Theoretical molecular weight (M n,th ) is calculated by the formula: M n,th =M w,CPDB +[MMA]0:[CPDB]0×M w,MMA ×Conv.g / mol, c Molecular weight (M n,GPC ) and molecular weight distribution The PMMA standard sample was measured by tetrahydrofuran (THF) phase gel permeation chromatography (GPC), and the results are shown in Table 1:

[0045] Table 1

[0046]

[0047] As can be seen from Table 1, by irradiating a micro-tube reactor with photothermal conversion function with near-infrared light, a polymer with controllable molecular weight and molecular weight distribution can be obtained under continuous flow conditions.

[0048] Obviously, the above embodiments are merely examples for clear explanation and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from these are still within the protection scope of the invention.

Claims

1. A method for preparing a micro-tube reactor with light-to-heat conversion function, characterized in that: The following steps are involved: S1. Using 3ds Max software to design a model of a microtubular reactor; the model includes a spiral microtubular reactor body; a microchannel is formed in the microtubular reactor body; and a liquid inlet and a liquid outlet connected to the microchannel are respectively formed at two ends of the microtubular reactor along the axial direction; S2. Printing with a 3D printer to obtain a micro-tube reactor; the material of the micro-tube reactor includes a photosensitive resin and a photothermal agent; the mass fraction of the photothermal agent is 0.01wt%-5.00wt%; S3, cleaning and curing the micro-tube reactor to obtain the micro-tube reactor with photothermal conversion function.

2. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S1, the inner diameter of the microchannel is 0.7 mm-1 mm, and the cross-sectional shape is selected from circular, elliptical, triangular, square or polygonal.

3. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S1, the spiral radius of the micro-tube reactor body is 10 mm-50 mm, the spiral density is 3.5 mm / turn-6 mm / turn, and the tube wall thickness is 0.5 mm-2 mm.

4. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S2, the 3D printer is selected from a digital light processing 3D printer or a liquid crystal photomask 3D printer.

5. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S2, the layer printing accuracy of the 3D printer is 0.025mm-0.05mm.

6. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S2, the photosensitive resin is selected from one or more of polyurethane acrylate, epoxy resin, polyimide, polyetherimide, polyetheretherketone and polyphenylene sulfide.

7. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S2, the photothermal agent is selected from one or more of cresol, phthalocyanine, graphene, carbon black, polyaniline, polypyrrole, polythiophene, polydopamine, lignin, gold nanoparticles, copper sulfide particles, carbon dots and indocyanine green.

8. The method for preparing a micro-tube reactor with a photothermal conversion function according to claim 1, characterized in that: In S3, the cleaning is performed by using ethanol; the curing is performed by using an ultraviolet lamp with a power of 25W-40W for 20min-60min, and the wavelength of the ultraviolet lamp is 355nm-405nm.

9. A micro-tube reactor with photothermal conversion function prepared by the method according to any one of claims 1 to 8.

10. Use of the micro-tube reactor with light-to-heat conversion function as claimed in claim 9 in a heating reaction.

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