A microwave microchannel combined reactor and its application

Abstract

This invention provides a microwave microchannel combined reactor and its application, including a reaction chamber and a microchannel reactor system inside the reaction chamber, comprising a microchannel cavity and multiple microchannel reactors disposed within the microchannel cavity, all made of plexiglass. One microchannel reactor at one end is connected to a feed pipe, and the other microchannel reactor at the other end is connected to a discharge pipe. Adjacent microchannel reactors are connected via reactor connecting pipes. A gas circulation system includes a circulating blower, a circulating inlet blower, and a gas source. One side of the microchannel cavity is connected to the gas source via the circulating blower, and the other side is connected to the gas source via the circulating inlet blower. A temperature-controlled circulation system includes a temperature-controlled circulation pump, with one end of each microchannel reactor connected to the outlet of the temperature-controlled circulation pump and the other end connected to the inlet of the temperature-controlled circulation pump. A microwave generator system includes multiple microwave generators disposed around the microchannel cavity.

Description

Technical Field

[0001] This application relates to the field of microwave microchannel technology, specifically to a microwave microchannel combined reactor and its application. Background Technology

[0002] Microwaves are ultra-high frequency electromagnetic waves in the band between radio waves and infrared radiation, with a frequency range of 300MHz to 300GHz and a wavelength of 1m to 1mm. Compared with other bands of electromagnetic waves, microwaves have unique characteristics, such as high frequency, short wavelength, and obvious quantum properties. When microwaves interact with matter, they exhibit three different properties depending on the physical properties of the matter: absorption, transmission, and reflection. Generally speaking, microwave materials can be divided into three categories: First, microwave reflecting materials, which are mainly good conductors such as bulk metals and alloys, such as aluminum and brass; second, microwave transmitting materials, which absorb almost no microwave energy and are microwave insulating media, transparent to microwaves, such as quartz, polytetrafluoroethylene, some glasses, and ceramics; and third, microwave absorbing materials, which can effectively absorb microwave energy and be rapidly heated, such as high dielectric loss materials like silicon carbide. Therefore, this type can be synthesized using microwave heating. When microwaves interact with matter, they exhibit both thermal and non-thermal effects.

[0003] Microwave heating technology differs significantly from traditional heating in that it involves heating materials in a high-frequency electromagnetic field. This heating is caused by the absorption of microwaves, leading to dielectric and conductivity losses, resulting in volumetric heating. In short, under the influence of the electromagnetic field, the polar molecular distribution of the dielectric material changes, shifting from a random distribution to an alignment aligned with the polarity of the electric field. During this shift, the molecular orientation changes continuously with the frequency of the alternating high-frequency electromagnetic field, causing molecular motion and friction. The energy exchange between these microscopic particles manifests as energy loss on a macroscopic scale, generating heat and continuously raising the temperature of the medium, thus achieving the heating purpose. Its characteristics include:

[0004] ① Volumetric heating characteristics. When microwaves heat a medium, the ultra-high frequency electromagnetic waves of microwaves enter the medium and interact directly with it. That is, the object being heated itself becomes the heat source. The object being heated absorbs microwave energy and heats up by relying on dielectric loss. This is conducive to the solid-state reaction. Therefore, microwave heating is called internal heating.

[0005] ② Selective heating with rapid heating rate and high heating efficiency. Microwaves have different effects on substances with different medium properties. The larger the loss tangent (tanδ) of a substance, the stronger its ability to absorb microwaves, and the higher the heating temperature. Therefore, this characteristic can be used to achieve selective heating or selective chemical reactions of substances using microwaves.

[0006] ③ Unique temperature control. Microwave heating begins with the generation of microwaves, the heating process has no lag effect, and it terminates when the microwaves disappear. Therefore, this characteristic can be fully utilized to microwave heat chemical reactions that require strict control of temperature and cooling rate.

[0007] ④ Energy-saving, efficient, and environmentally friendly. Since microwave energy is directly absorbed by materials and converted into heat energy, it has high thermal efficiency. At the same time, microwave heating itself does not produce gas, so the amount of gas that needs to be treated and purified is small, chemical pollution is low, and the usage environment is significantly improved.

[0008] ⑤ It lowers the temperature of chemical reactions and has a catalytic effect. Microwave heating can simultaneously promote exothermic and endothermic reactions, improving the kinetic conditions of the reaction; at the same time, microwave electromagnetic energy can cause particles to vibrate at high speeds, which to some extent lowers the temperature of chemical reactions. Existing experiments have shown that high-temperature chemical reactions can be carried out at relatively low temperatures, which creates more favorable thermodynamic conditions for chemical reactions.

[0009] The structure of the microwave device: The microwave equipment used in this experiment mainly consists of the following systems: a microwave generator, a synthetic heating cavity, a microwave system and waveguide elements, a control and detection system, and a vacuum and atmosphere control system. The microwave generator uses a magnetron for oscillation at a frequency of 2450MHz, with a heating power of 0–3kW. The power output is controlled in real time and continuously adjustable, ensuring high temperature control accuracy during heating, thus preventing thermal runaway to a certain extent. The synthetic heating cavity is the core of the entire microwave heating system; it is the site of interaction between electromagnetic waves and matter and can be considered as an extended waveguide. The design of the synthetic heating cavity has a significant impact on material heating and electromagnetic field distribution; therefore, when designing the cavity dimensions, it is essential to fully consider the shape and processing requirements of the materials being processed, as well as the distribution of the field strength.

[0010] Because microwave reactions involve large temperature variations, traditional reaction equipment cannot quickly transfer or exchange the heat generated by microwaves. Microwave reactions can only be carried out in laboratories or on a small scale. The safety of scale-up has always been one of the challenges of microwave reactions.

[0011] Microchannel reaction (MSR) technology originated in research institutions in Europe and the United States in the 1990s. In the early stages, it was mainly used for theoretical and small-scale experimental research. Due to the great difficulty in manufacturing microreactors, the experimental throughput was also very limited, which prevented it from being widely used in production. In the early 21st century, with the application of new materials such as high-strength plexiglass and silicon carbide ceramics, MSR technology made rapid progress in developed countries in Europe and the United States. Major international pharmaceutical and chemical companies such as Bayer, Bristol-Myers Squibb, DSM, and Merck have all achieved industrial production of MSR technology.

[0012] Microchannel reactors are characterized by mixing and mass transfer efficiency 1000 times that of traditional batch reactors and heat exchange rate 100 times that of traditional batch reactors, making them ideal for high-risk, exothermic reactions in industrial production. For example, nitration and diazotization reactions, which are subject to the low mass and heat transfer efficiency of traditional reactors, pose a risk of explosion due to the accumulation of energy and the inability to dissipate heat during operation.

[0013] Microchannel reactors have low liquid holding capacity, which can effectively reduce safety risks. The liquid holding volume is about one two-thousandth of that of conventional batch reactors. The safety factor beta value is reduced from 6 to 8 for batch reactors to 0.2. The explosive destructive force is reduced geometrically, and the safety of chemical reactions can be greatly guaranteed. This is a disruptive innovation that ensures the inherent safety of the synthesis process.

[0014] "Green chemistry" is widely recognized as one of the most important scientific fields of the 21st century and a fundamental scientific means of pollution prevention. Green chemistry has brought revolutionary changes to the traditional chemical industry in both principle and methodology. Microchannel reactions, with their highly efficient mass and heat transfer, can complete reactions within tens of seconds. In process optimization, they can remove or significantly reduce highly volatile and polluting organic solvents; some reactions are even solvent-free, achieving zero emissions. Continuous flow reactions, requiring no separation, embody the environmentally friendly and green chemical reaction characteristics of microchannel reactions.

[0015] Therefore, the characteristics of microchannel reactions are: inherently safe, green and environmentally friendly, no scale-up effect, energy-saving, economical and low-carbon, continuous and automated and fast.

[0016] Due to factors such as short reaction time, selective chemical reaction application, and limitations in capacity scaling due to expensive equipment, the application and promotion of microchannel reactors in the domestic pharmaceutical and chemical industries has been relatively slow.

[0017] Currently, microchannel reactors can be broadly classified into three types:

[0018] (1) Microchannel reactors with reflux and heat exchange functions (compared with conventional reactors, mass transfer can be increased by 1000 times and heat exchange by 100 times. The reactor module materials are mainly organic glass, stainless steel, titanium alloy and silicon carbide ceramics). Other connecting parts are mainly made of stainless steel and titanium alloy. Currently, the microchannel reactors with 1000 times mass transfer and 100 times heat exchange that have been industrialized are all of this type. However, since the modules or connecting parts of this type of microchannel reactor are all made of organic materials, they cannot be directly put into microwave ovens for experimental research or industrial production.

[0019] (2) Tubular microchannel reactors with recirculation function (mass transfer 10-100 times, heat exchange 0 times) are generally used for solution mixing.

[0020] (3) Microtube reaction, the material is generally organic engineering plastic, plexiglass, stainless steel and other metals (mass transfer 10-50 times, heat exchange 0 times), the inner diameter of the tube is generally 0.01-10 mm. Due to the limited mass transfer capacity and lack of heat exchange, it is generally only used for laboratory research and cannot be industrialized. The more convenient way is to use organic plastic tubes with a certain length (1-100 meters) and a small inner diameter (0.01-5 mm) in a microwave oven to carry out microtube reaction. Since microtube reaction has no liquid material return function, the mass transfer capacity is very limited. Compared with conventional reaction, the improvement of reaction effect is limited. Especially in recent years, with the rapid development of microchannel reactors (mass transfer 1000 times, heat exchange 100 times) at home and abroad and the increasing industrial application, the enthusiasm for microtube reaction research is decreasing and is generally limited to laboratory research.

[0021] Currently, there is considerable research on microchannel and microwave reactions both domestically and internationally, and their industrial applications are progressing to some extent. However, there are no reports on the research and industrial applications of combinations of microwaves and microchannels (1000 times mass transfer, 100 times heat exchange). Therefore, the combined equipment and applications of microwaves and microchannels (1000 times mass transfer, 100 times heat exchange) are still a blank area both domestically and internationally. Summary of the Invention

[0022] In view of the above-mentioned defects or deficiencies in the prior art, one of the objectives of this application is to provide a microwave microchannel combined reactor, including a reaction chamber, and further including the following inside the reaction chamber:

[0023] A microchannel reactor system includes a microchannel cavity and multiple microchannel reactors disposed within the microchannel cavity. The multiple microchannel reactors are all made of plexiglass. The microchannel reactor at one end is connected to a feed pipe, and the microchannel reactor at the other end is connected to a discharge pipe. Adjacent microchannel reactors are connected to each other through reactor connecting pipes.

[0024] A gas circulation system includes a circulating blower, a circulating intake blower, and a gas source. One side of the microchannel cavity is connected to the gas source through the circulating blower, and the other side is connected to the gas source through the circulating intake blower.

[0025] A temperature-controlled circulation system includes a temperature-controlled circulation pump, wherein one end of each microchannel reactor is connected to the outlet of the temperature-controlled circulation pump, and the other end is connected to the inlet of the temperature-controlled circulation pump; and

[0026] A microwave generator system comprising multiple microwave generators disposed around the microchannel cavity.

[0027] According to the technical solution provided in the embodiments of this application, the microchannel reactor system further includes a reactor mounting bracket, with each microchannel reactor having its two ends fixed to the opposite inner walls of the reactor mounting bracket, and the reactor mounting bracket being a non-metallic frame structure.

[0028] According to the technical solution provided in the embodiments of this application, the two ends of the microchannel reactor are respectively fixed to the reactor mounting bracket by the reactor positioning back plate, and then sealed and fixed to the outside of the reactor positioning back plate by a connecting sealing ring and a universal snap ring sealing joint. The reactor positioning back plate, the connecting sealing ring and the universal snap ring sealing joint are all made of non-metallic materials.

[0029] According to the technical solution provided in the embodiments of this application, a temperature measuring point for the inlet of the temperature-controlled circulating liquid and a temperature measuring point for the outlet of the temperature-controlled circulating pump are respectively set on the pipe connecting the outlet and inlet of each microchannel reactor to the outer wall of the microchannel cavity.

[0030] According to the technical solution provided in the embodiments of this application, the microchannel reactor system further includes a microwave voltage regulator, a microwave voltage indicator, and a microwave control switch connected to the plurality of microwave generators.

[0031] According to the technical solution provided in the embodiments of this application, the microwave microchannel combined reactor further includes at least one of the following solutions:

[0032] Option 1: The microwave microchannel combined reactor also includes a safety relief valve installed on the outer side wall of the reactor chamber;

[0033] Option 2: The feed pipe is equipped with a feed metering pump and a feed pipe control pressure gauge, and the discharge pipe is equipped with a discharge pressure control valve;

[0034] Option 3: The gas source is equipped with an intake pipe containing an intake valve, an outlet branch pipe containing a circulation control valve, and a relief valve connected to the atmosphere;

[0035] Option 4: The gas source is a nitrogen cylinder.

[0036] According to the technical solution provided in the embodiments of this application, the microwave microchannel combined reactor further includes at least one of the following solutions:

[0037] Option 1: The temperature control range of the temperature-controlled circulating pump is -40 to 200℃;

[0038] Option 2: The control voltage of the microwave generator is 2-12V;

[0039] Option 3: The sealing pressure requirement of the connecting sealing ring exceeds 20 kg / cm². 2 Working pressure requirement: 10-15 kg / cm2 .

[0040] The microwave microchannel combined reactor includes at least one of the following:

[0041] Option 1: The materials of the reactor mounting bracket, the connecting sealing ring, and the universal snap ring sealing joint include one or more of the following: polycarbonate, polyamide, polyacetal, modified polyphenylene ether, polyester, polyphenylene sulfide, polyaryl ester, polybutylene terephthalate, polyphenylene sulfide, polyarylsulfone, polyetheretherketone, polyvinyl alcohol, Teflon, polyethylene, polypropylene, polyvinylidene fluoride, polyphthalamide, and polyester resin (PET).

[0042] Option 2: The door of the reaction chamber is located at the front, and the door material includes stainless steel and / or plexiglass.

[0043] In the microwave microchannel combined reactor, both the temperature measurement points at the inlet and outlet of the temperature-controlled circulating liquid are monitored using metal temperature probes.

[0044] The second objective of this application is to provide an application of the microwave microchannel combined reactor as described in any of the above technical solutions, wherein the microwave microchannel combined reactor can be used for chemical synthesis reactions, including halogenation, nitration, sulfonation, diazotization, oxidation, reduction, elimination, alkylation, acylation, condensation, cyclization and rearrangement reactions.

[0045] In summary, this application proposes a microwave microchannel combined reactor and its application. The core innovation of this invention lies in the overall design of the microwave microchannel (1000 times mass transfer, 100 times heat transfer) combined reactor system, which combines microchannel reactors made of plexiglass (1000 times mass transfer, 100 times heat transfer) under microwave conditions. This design achieves the safety and resilience of the microchannel reactor under microwave conditions; high temperature and high pressure resistance; airtightness and leak-free operation of the microchannel reactor (plexiglass material); precise control of microwave voltage and temperature; precise control of the inlet and outlet temperatures of the circulating liquid in the microwave microchannel combined reactor; and safe circulation control of nitrogen within the reactor chamber.

[0046] In summary, the present invention has the following beneficial effects:

[0047] (1) The industrial application of microwave microchannel (1000 times mass transfer, 100 times heat transfer) combined reactor has been realized, maximizing the powerful and rapid heating capacity of microwaves and the 1000 times mass transfer and 100 times heat exchange capacity of microchannels; by utilizing the rapid absorption of microwaves by the reactants, the reactants are heated in bulk (internal heating) and the external heat exchange of the microchannels is achieved (external heating), which is easy to industrialize and achieves complementary advantages.

[0048] (2) By utilizing the strong heat exchange capacity of microwave microchannels (1000 times mass transfer and 100 times heat transfer), the shortcomings of industrial application of microwave generators are effectively solved. This is because microwave generators are prone to causing sudden temperature jumps in reactants, resulting in byproducts and potential explosions, thus achieving inherent safety in the reaction.

[0049] (3) The microwave microchannel (mass transfer 1000 times, heat transfer 100 times) combined reactor can achieve precise and stable control of the reaction materials during the reaction process by reasonably controlling the temperature of the reaction materials, reducing the production of by-products and improving product quality.

[0050] (4) The microwave microchannel (mass transfer 1000 times, heat transfer 100 times) combined reactor can achieve complete conversion of reactants under low temperature conditions. Under the same temperature and time conditions, the conversion rate of reactants can be greatly improved (compared with pure microchannel rather than conventional reaction). Chemical reactions can be completed in a small amount of solvent or pure water phase, and green and environmentally friendly industrial production can be realized.

[0051] (5) The microwave microchannel combined reactor can reduce the amount of palladium-carbon used in the palladium-carbon hydrogenation reduction reaction and reduce production costs. Attached Figure Description

[0052] Figure 1 A flowchart of a microwave microchannel combined reactor provided in an embodiment of this application.

[0053] The text labels in the image represent:

[0054] 1-Microchannel reactor No. 1, 2-Microchannel reactor No. 2, 3-Microchannel reactor No. 3, 4-Microchannel reactor No. 4, 5-Microchannel reactor No. 5, 6-Lower microwave generator, 7-Left microwave generator, 8-Emergency button, 9-Emergency indicator light, 10-Microwave voltage regulator, 11-Microwave voltage indicator, 12-Circulating fan, 13-Temperature measuring point at the outlet of the temperature-controlled circulating liquid, 14-Temperature measuring point at the inlet of the temperature-controlled circulating liquid, 15-Upper microwave generator, 16-Safety relief valve, 17-Microwave control switch 18--Reactor positioning backplate, 19--Connecting sealing ring, 20--Reactor mounting bracket, 21--Reactor connecting pipe, 22--Right microwave generator, 23--Reactor metal shell, 24--Circulating air intake fan, 25--Feed pipe control pressure gauge, 26--Feed metering pump, 27--Discharge pressure control valve, 28--Gas source, 29--Inlet valve, 30--Gas source explosion relief valve, 31--Circulation control valve, 32--Temperature-controlled circulation pump, 33--Reaction chamber, 34--Microchannel cavity, 35--Feed pipe, 36--Discharge pipe. Detailed Implementation

[0055] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, only the parts relevant to the invention are shown in the accompanying drawings.

[0056] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0057] Example 1

[0058] refer to Figure 1 This embodiment provides a microwave microchannel combined reactor, including a reaction chamber 33, and a microchannel reactor system, a gas circulation system, a temperature control circulation system and a microwave generator system inside the reaction chamber 33. The microchannel reactor system includes a microchannel cavity 34 and multiple microchannel reactors disposed within the microchannel cavity 34. The multiple microchannel reactors are all made of plexiglass. The microchannel reactor located at one end is connected to the feed pipe 35, and the microchannel reactor located at the other end is connected to the discharge pipe 36. Adjacent microchannel reactors are connected to each other through a reactor connecting pipe 21. The gas circulation system includes a circulating blower 12, a circulating inlet blower 24, and a gas source 28. One side of the microchannel cavity 34 is connected to the gas source 28 through the circulating blower 12, and the other side is connected to the gas source 28 through the circulating inlet blower 24. The temperature control circulation system includes a temperature control circulation pump 32. One end of each microchannel reactor is connected to the outlet of the temperature control circulation pump 32, and the other end is connected to the inlet of the temperature control circulation pump 32. The microwave generator system includes multiple microwave generators arranged around the microchannel cavity 34.

[0059] Specifically, in this embodiment, five microchannel reactors are installed within the microchannel cavity: microchannel reactor 1, microchannel reactor 2, microchannel reactor 3, microchannel reactor 4, and microchannel reactor 5. Microchannel reactor 5 is connected to the feed pipe 35, and microchannel reactor 1 is connected to the discharge pipe 36. The microwave generators around the microchannel cavity 34 are evenly distributed, and 1-n microwave generators can be installed on each side of the microchannel cavity 34. The microwave voltage of all microwave generators can be selected from 0.2-24V. Specifically, in this embodiment, one microwave generator is installed around the microwave reactor at the top, bottom, left, and right, namely, upper microwave generator 15, lower microwave generator 6, left microwave generator 7, and right microwave generator 22, and the microwave voltage of each microwave generator is 2-12V.

[0060] Preferably, the microchannel reactor system of this embodiment further includes a reactor mounting bracket 20. Each microchannel reactor is fixed at both ends to the opposing inner walls of the reactor mounting bracket 20. The reactor mounting bracket 20 is a non-metallic H-shaped frame structure. Because metals have high electrical conductivity, sparks can be generated on the sharp edges and corners of metals under microwave conditions, potentially causing explosions during assembly and posing a safety hazard. Since acrylic glass cannot be used for component connection using conventional welding or threading processes, all microchannel reactors in this embodiment are mounted on the reactor mounting bracket 20 using a bolt and nut installation process.

[0061] Optionally, both ends of each microchannel reactor are fixed to the reactor mounting bracket 20 via the reactor positioning back plate 18, and then sealed and fixed to the outside of the reactor positioning back plate 18 using a connecting sealing ring 19 and a universal snap ring sealing joint. The reactor positioning back plate 18, the connecting sealing ring 19, and the universal snap ring sealing joint are all made of non-metallic materials. Specifically, a threaded thrust sealing process is used to fix the U-shaped connecting sealing ring 19 to the outside of the reactor positioning back plate 18 via the universal snap ring sealing joint.

[0062] Furthermore, a temperature measuring point 14 for the inlet of the temperature-controlled circulating liquid and a temperature measuring point 13 for the outlet of the temperature-controlled circulating liquid are respectively set on the outer wall of the microchannel cavity 34 on the pipe connecting the outlet and inlet of each microchannel reactor to the temperature-controlled circulating pump 32. The temperature monitoring points are selected at locations on the outer metal pipe of the circulating liquid, adjacent to the microchannel cavity 34 and close to the junction of the inner and outer parts of the microchannel reactor, resulting in more accurate temperature monitoring. Preferably, in this embodiment, metal temperature probes are used to monitor the temperature at both the temperature measuring point 14 and the temperature measuring point 13 of the temperature-controlled circulating liquid, as metal temperature probes are more sensitive and accurate in detecting temperature.

[0063] Optionally, the microchannel reactor system also includes a microwave voltage regulator 10, a microwave voltage indicator 11, and a microwave control switch 17 connected to multiple microwave generators, and is also equipped with an emergency button 8 and an emergency indicator light 9.

[0064] Furthermore, for safety and reliability, the microwave microchannel combined reactor in this embodiment also includes a safety relief valve 16 disposed on the outer wall of the reaction chamber 33. A feed metering pump 26 and a feed pipe control pressure gauge 25 are installed on the feed pipe 35, and a discharge pressure control valve 27 is installed on the discharge pipe 36. The gas source 28 is provided with an inlet pipe containing an inlet valve 29, an outlet branch pipe containing a circulation control valve 31, and a gas source relief valve 30 connected to the atmosphere.

[0065] Optionally, in this embodiment, the gas source 28 is a nitrogen tank. The microwave microchannel combined reactor employs a closed-loop nitrogen circulation system, with added forced air supply and forced exhaust designs, effectively controlling the temperature within the reactor's internal cavity. A temperature alarm is also included to automatically stop the associated microwaves upon reaching a certain temperature, ensuring safety and reliability. This embodiment also incorporates additional safety protection measures, such as a spring safety valve, on the nitrogen tank.

[0066] Preferably, in this embodiment, a reactor metal shell 23 is also provided inside the reaction chamber 33, and the aforementioned emergency button 8, emergency indicator light 9, microwave voltage regulator 10, microwave voltage indicator 11 and microwave control switch 17 are all provided on the reactor metal shell 23.

[0067] Furthermore, in this embodiment, the temperature control range of the temperature-controlled circulating pump 32 is -40 to 200°C; the control voltage of each microwave generator is 2-12V; and the sealing pressure requirement of the connecting sealing ring 19 exceeds 20 kg / cm². 2 Working pressure requirement: 10-15 kg / cm 2 .

[0068] In this embodiment, the non-metallic materials can be selected from engineering plastic materials, such as polycarbonate (PC), polyamide (PA), polyacetal (POM), modified polyphenylene ether (modified PPE), polyester (PETP, PBTP), polyphenylene sulfide (PPS), polyaryl ester, polybutylene terephthalate (PBT), polyphenylene sulfide (PPS), polyarylsulfone (PAR), PEEK (polyether ether ketone), polyvinyl alcohol (PVA), Teflon (PEFT), polyethylene (PE), polypropylene (PP), polyvinylidene fluoride (PVDF), polyphthalamide (PPA), polyester resin (PET), etc.

[0069] Preferably, the non-metallic engineering plastic is one or more of PVDF, PET, PEFT, PEEK, and PPA.

[0070] Preferably, both the reactor positioning backplate 18 and the reactor mounting bracket 20 are made of PEFT or PVDF. More preferably, both the reactor positioning backplate 18 and the reactor mounting bracket 20 are made of PEFT.

[0071] Preferably, the fixing bolts and nuts used for the reactor positioning back plate 18 and the reactor mounting bracket 20 are made of PEEK.

[0072] Preferably, the connecting sealing ring 19 is made of PEEK, PVDF, or PEFT. More preferably, the connecting sealing ring 19 is made of PEEK.

[0073] Preferably, the universal retaining ring sealing joint is made of PVDF.

[0074] Preferably, the thrust bolts used for the connecting sealing ring 19 and the universal snap ring sealing joint are made of PVDF or PEEK. More preferably, the thrust bolts used for the connecting sealing ring 19 and the universal snap ring sealing joint are made of PEEK.

[0075] The microwave microchannel combined reactor features a front door design, with the door material suitable for materials such as stainless steel or acrylic glass. Preferably, the door design incorporates a stainless steel frame inlaid with acrylic glass to enhance visibility during the reaction process.

[0076] The microwave microchannel combined reactor provided by this invention is used for chemical synthesis reactions and can be used for halogenation, nitration, sulfonation, diazotization, oxidation, reduction, elimination, alkylation, acylation, condensation, cyclization and rearrangement reactions, etc.

[0077] Preferably, the microwave-microchannel combined reactor can be used for nitration, halogenation, diazotization, and reduction reactions. More preferably, the microwave-microchannel combined reactor can be used for high-pressure hydrogenation reduction reactions.

[0078] Example 2

[0079] Reaction equation:

[0080]

[0081] Experimental procedure:

[0082] Weigh 200g of raw material and add it to methanol, stirring to dissolve. Then add 6g of palladium-carbon as a catalyst and stir until homogeneous as material I. Control the flow rate of H2 as material II. Control the slurry pump and gas flow meter to maintain the molar ratio of raw material to hydrogen at 1:3. Control the reaction time of the material at 42 seconds and set the external circulation temperature of the reaction at 60℃. After the material reaches a steady state, turn on the microwave oven (both vertical and horizontal) and control the microwave voltage at 2.667V. After the material reaches a steady state again, the material can be received from the module outlet for further detection and processing of the liquid.

[0083] Test data

[0084]

[0085] Note: The amount of palladium-carbon used in the above reaction is 3.0%, and the pressure of the reaction module is 10 kg / cm². 2 .

[0086] in conclusion:

[0087] 1) When the microwave instrument is turned off, the reaction conversion rate increases with the increase of the temperature controller, but the rate of increase is slow;

[0088] 2) When the microwave instrument is turned on, the conversion rate increases significantly with the increase of power;

[0089] 3) Temperature controllers show significant differences in reaction products at the same temperature and reaction time. When the microwave-microchannel combined reactor reaches the endpoint, the product content can be increased by more than 40% compared to the reactor without microwave.

[0090] Example 3

[0091] Reaction equation:

[0092]

[0093] Experimental procedure:

[0094] Weigh 100g of raw material and add it to ethyl acetate and stir to dissolve. Then add 2.5g of palladium-carbon as a catalyst and stir evenly to obtain material I. Control the flow rate of H2 to obtain material II. Control the slurry pump and gas flow meter to maintain the molar ratio of raw material to hydrogen at 1:3. Control the reaction time of the material at 44 seconds and set the external circulation temperature of the reaction at 90℃. After the material reaches a steady state, turn on the microwave instrument (up / down and left / right) and control the microwave voltage at 3.002V. After the material reaches a steady state again, the material can be received from the module outlet for further detection and processing of the liquid.

[0095] Experimental data:

[0096]

[0097] Note: The amount of palladium-carbon used in the above reaction is 2.5%, and the pressure of the reaction module is 10 kg / cm². 2 .

[0098] in conclusion:

[0099] 1) The microwave microchannel combined reactor can reach the target endpoint at 90 degrees Celsius for 44 seconds;

[0100] 2) When the microwave instrument is turned on, the conversion rate increases significantly with the increase of power;

[0101] 3) Temperature controllers show significant differences in reaction products at the same temperature and reaction time. When the microwave-microchannel combined reactor reaches the endpoint, the product content can be increased by more than 30% compared to that without microwave.

[0102] Example 4

[0103] Reaction equation:

[0104]

[0105] Experimental procedure:

[0106] Weigh 150g of raw material and add it to anhydrous ethanol and stir to dissolve. Then add 6.0g of palladium-carbon as a catalyst and stir evenly to form material I. Control the flow rate of H2 to form material II. Control the slurry pump and gas flow meter to maintain the molar ratio of raw material to hydrogen at 1:1. Control the reaction time of the material to 35 seconds. Set the external circulation temperature of the reaction to 100℃. After the material reaches a steady state, turn on the microwave instrument (up / down and left / right) and control the microwave voltage to 3.432V. After the material reaches a steady state again, the material can be received from the module outlet for further detection and processing of the liquid.

[0107] Experimental data:

[0108]

[0109] Conclusion: The microwave-microchannel combined reactor can reach the target endpoint at 100 degrees Celsius for 35 seconds, with a conversion rate of over 92%, which is 20% higher than that of the microchannel reactor under the same process conditions.

[0110] Example 5

[0111] Reaction equation:

[0112]

[0113] Experimental procedure:

[0114] Weigh 200g of raw material and add it to anhydrous methanol and stir to dissolve. Then add 5.0g of palladium-carbon as a catalyst and stir evenly to obtain material I. Control the flow rate of H2 to obtain material II. Control the slurry pump and gas flow meter to maintain the molar ratio of raw material to hydrogen at 1:3. Control the reaction time of the material at 37 seconds and set the external circulation temperature of the reaction at 70℃. After the material reaches a steady state, turn on the microwave instrument (up / down and left / right) and control the microwave voltage at 4.515V. After the material reaches a steady state again, the material can be received from the module outlet for further detection and processing of the liquid.

[0115] Experimental data:

[0116]

[0117] in conclusion:

[0118] 1) Compared with microchannel reactors, microwave microchannel combined reactors can reduce the amount of palladium-carbon used by more than 50%, thus reducing the cost of palladium-carbon.

[0119] 2) The microwave-microchannel combined reactor can reach the target endpoint at 70 degrees Celsius and 37 seconds, with a conversion rate of over 92%, which is 35% higher than that of the microchannel reactor under the same process conditions.

[0120] Example 6

[0121] Reaction equation:

[0122]

[0123] Experimental procedure:

[0124] Weigh 100g of raw material and add it to acetonitrile, stirring to dissolve. Then add 1.5g of palladium-carbon as a catalyst and stir until homogeneous as material I. Control the flow rate of H2 as material II. Control the slurry pump and gas flow meter to maintain the molar ratio of raw material to hydrogen at 1:1. Control the reaction time of the material at 36 seconds and set the external circulation temperature of the reaction at 50℃. After the material reaches a steady state, turn on the microwave instrument (both vertical and horizontal) and control the microwave voltage at 3.923V. After the material reaches a steady state again, the material can be received from the module outlet for further detection and processing of the liquid.

[0125] Experimental data:

[0126]

[0127] in conclusion:

[0128] 1) Compared with microchannel reactors, microwave microchannel combined reactors can reduce the amount of palladium-carbon used by more than 50%, thus reducing the cost of palladium-carbon.

[0129] 2) The microwave-microchannel combined reactor can reach the target endpoint at 50 degrees Celsius and 36 seconds, with a conversion rate of over 97%, which is nearly 80% higher than that of the microchannel reactor under the same process conditions.

[0130] 3) Turn off the circulating temperature controller (only turn on the circulating pump), and the reaction heating relies entirely on microwave heating (using the circulating pump for safe temperature control). The reaction speed is significantly accelerated, and the outlet temperature of the reaction module is below 55 degrees Celsius.

[0131] 4) The microwave microchannel combined reactor can achieve high-pressure reactions, with the reaction pressure controlled at 10-15 kg / cm³. 2 (Unloaded safety test pressure reaches 18 kg / cm²) 2 ).

[0132] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above descriptions are only preferred embodiments of this application. It should be noted that due to the limitations of written expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this invention, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.

Claims

1. A microwave microchannel combined reactor, comprising a reaction chamber (33), characterized in that, It also includes the interior of the reaction chamber: The microchannel reactor system includes a microchannel cavity (34) and five microchannel reactors disposed within the microchannel cavity (34). The five microchannel reactors are all made of plexiglass. The microchannel reactor at one end is connected to the feed pipe (35), and the microchannel reactor at the other end is connected to the discharge pipe (36). Adjacent microchannel reactors are connected to each other through a reactor link pipe (21). The gas circulation system includes a circulating blower (12), a circulating intake blower (24), and a gas source (28). One side of the microchannel cavity is connected to the gas source (28) through the circulating blower (12), and the other side is connected to the gas source (28) through the circulating intake blower (24). A temperature-controlled circulation system includes a temperature-controlled circulation pump (32), with one end of each microchannel reactor connected to the outlet of the temperature-controlled circulation pump (32) and the other end connected to the inlet of the temperature-controlled circulation pump (32); and The microwave generator system includes multiple microwave generators disposed around the microchannel cavity (34); the microwave generators around the microchannel cavity are uniformly distributed, and 1-n microwave generators are installed on each side inside the microchannel cavity, and the microwave voltage of all microwave generators is 2-12V. The microchannel reactor system also includes a reactor mounting bracket (20), with each microchannel reactor having its two ends fixed to the opposite inner walls of the reactor mounting bracket (20). The reactor mounting bracket (20) is a non-metallic frame structure. The two ends of the microchannel reactor are fixed to the reactor mounting bracket (20) by the reactor positioning back plate (18) respectively, and then sealed and fixed to the outside of the reactor positioning back plate (18) by the connecting sealing ring (19) and the universal snap ring sealing joint. The reactor positioning back plate (18), the connecting sealing ring (19) and the universal snap ring sealing joint are all made of non-metallic materials. The microwave microchannel combined reactor also includes a safety relief valve (16) installed on the outer wall of the reaction chamber (33). The feed pipe (35) is equipped with a feed metering pump (26) and a feed pipe control pressure gauge (25), and the discharge pipe (36) is equipped with a discharge pressure control valve (27). The gas source (28) is provided with an inlet pipe containing an inlet valve (29), an outlet branch pipe containing a circulation control valve (31), and a gas source explosion relief valve (30) connected to the atmosphere. The gas source (28) is a nitrogen cylinder; The temperature control range of the temperature-controlled circulating pump (32) is -40 to 200℃; The sealing pressure requirement of the connecting sealing ring (19) is required to exceed 20 kg / cm². 2 Working pressure requirement: 10-15 kg / cm 2 ; The reactor mounting bracket (20), the connecting sealing ring (19), and the universal snap ring sealing joint are made of one or more of the following materials: polycarbonate, polyamide, polyacetal, modified polyphenylene ether, polyaryl ester, polybutylene terephthalate, polyphenylene sulfide, polyarylsulfone, polyether ether ketone, polyvinyl alcohol, Teflon, polyethylene, polypropylene, polyvinylidene fluoride, polyphthalamide, and polyester resin (PET). The door of the reaction chamber (33) is located at the front, and the door material includes stainless steel and / or plexiglass.

2. The microwave microchannel combined reactor according to claim 1, characterized in that, Temperature measuring points (14) at the inlet and (13) of the temperature-controlled circulating liquid are respectively set on the pipes connecting the outlet and inlet of the temperature-controlled circulating pump (32) to the outer wall of the microchannel cavity (34).

3. The microwave microchannel combined reactor according to claim 2, characterized in that, The microchannel reactor system also includes a microwave voltage regulator (10), a microwave voltage indicator (11), and a microwave control switch (17) connected to the plurality of microwave generators.

4. The microwave microchannel combined reactor according to claim 3, characterized in that, The temperature at the inlet measuring point (14) and outlet measuring point (13) of the temperature-controlled circulating fluid are both monitored using metal temperature probes.

5. An application of the microwave microchannel combined reactor as described in any one of claims 1-4, characterized in that, The microwave microchannel combined reactor can be used for chemical synthesis reactions, including halogenation, nitration, sulfonation, diazotization, oxidation, reduction, elimination, alkylation, acylation, condensation, cyclization, and rearrangement reactions.

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