CN220328608U - Device for preparing methyl isoamyl ketone - Google Patents

Abstract

The present utility model provides an apparatus for preparing methyl isoamyl ketone. The device comprises: reactant mixer, heat exchanger and reaction kettle; the reactant mixer includes a first reactant inlet and a dehydration catalyst inlet; an inlet of the heat exchanger is connected with an outlet of the reactant mixer; the reaction kettle comprises a Venturi ejector, a reducing gas inlet and a hydrogenation catalyst inlet; the venturi ejector is arranged at the top of the reaction kettle, the inlet of the venturi ejector is connected with the outlet of the heat exchanger, and the inlet of the second reactant is connected with the inlet of the venturi ejector. Compared with the prior art, the utility model has at least one of the following beneficial effects: the method improves the yield of the product, reduces the discharge of three wastes, reduces the production cost, has convenient continuous operation, high reaction yield, saves energy and protects environment, and is suitable for industrial production.

Description

Apparatus for the preparation of methyl isopentyl ketone

Technical field

The utility model relates to the technical field of organic synthesis, specifically to a device for preparing methyl isopentyl ketone.

Background technique

Methyl Isoamyl Ketone (MIAK for short), chemical name is 5-methyl-2-hexanone, is a colorless and transparent liquid with light aroma. Mainly used as a solvent for cellulose acetate, acrylic resin, polyvinyl formal resin, etc. It can also be used in organic synthesis and is the main raw material for preparing p-phenylenediamine rubber antioxidants 7PPD, 77PD and TMPPD. However, at present, methyl isopentyl ketone industrial units generally adopt a batch-kettle two-step method or a one-step method for synthesis. Under the action of a catalyst, the reactants undergo condensation, dehydration and hydrogenation reactions to generate methyl isoamyl ketone. However, there are many shortcomings in the methyl isoamyl ketone industrial equipment and synthesis methods used in related technologies: the catalyst used has poor catalytic activity, low reactant conversion rate, poor selectivity, low product purity, many side reactions, and synthetic steps The process is complex, the equipment is highly corrosive and a large amount of waste liquid is produced, so it is not suitable for industrial production.

Therefore, the current apparatus for preparing methyl isoamyl ketone still needs to be improved.

Utility model content

In view of the deficiencies in the prior art, the purpose of this utility model is to provide a device for preparing methyl isopentyl ketone to solve the problems raised in the above background technology.

The utility model provides a device for preparing methyl isoamyl ketone, which device includes: a reactant mixer, a heat exchanger and a reaction kettle; the reactant mixer includes a first reactant inlet and a dehydration catalyst The inlet is used to mix the first reactant and the dehydration catalyst; the inlet of the heat exchanger is connected with the outlet of the reactant mixer to heat the mixed reactants; the reaction kettle includes a Venturi ejector, a reduction Gas inlet and hydrogenation catalyst inlet; the Venturi injector is located at the top of the reaction kettle, the inlet of the Venturi injector is connected to the outlet of the heat exchanger, and the second reactant inlet is connected to the Venturi injector. The inlet of the injector is connected.

Further, the device includes a solid-liquid separation unit, which includes a mixture inlet, a clean liquid product outlet, and a slurry catalyst outlet. The mixture inlet is connected to the outlet of the heat exchanger, and the slurry catalyst The outlet is connected to the inlet of the venturi injector.

Furthermore, the bottom of the reaction kettle is provided with a material outlet, and the material outlet is connected to the inlet of the heat exchanger. The device further includes a circulation pump to circulate between the reaction kettle, the solid-liquid separation unit and A material circulation loop is formed between the heat exchangers.

The circulation pump is installed in the pipeline between the material outlet and the outlet of the heat exchanger.

Furthermore, the head of the circulation pump is configured such that the pressure difference between the inlet and outlet of the circulation pump is not less than 0.3MPa.

Furthermore, the circulation volume of the circulation pump is 20 to 50 times the volume of the reaction kettle.

Furthermore, the circulation pump is a magnetic pump or a centrifugal pump.

Further, the solid-liquid separation unit is a cross-flow filter.

Further, the device further includes a reducing gas buffer tank; the reducing gas buffer tank includes a liquid product inlet, a methyl isoamyl ketone outlet, a purge gas outlet and a gas vent; wherein, the liquid product inlet and the The clean liquid product outlet is connected, and the purge gas outlet is connected to the slurry catalyst outlet to purge the slurry catalyst into the Venturi injector.

Furthermore, the reducing gas buffer tank and the reaction kettle are connected through a balance pipe to stabilize the partial pressure of the reducing gas in the reaction kettle.

Furthermore, the reducing gas buffer tank further includes a pressurizing pipe to perform hydrogen pressure compensation in the reducing gas buffer tank.

Further, the aspect ratio of the reaction kettle is 2-8.

Further, the Venturi injector includes a material inlet, a nozzle, a mixing chamber and a diffuser connected in sequence, and has an air chamber connected to the mixing chamber, the material inlet is located at the top of the reaction kettle, and the The material inlet is connected to the outlet of the heat exchanger, and the opening of the diffuser faces the inside of the reaction kettle.

Further, in the Venturi injector: there is an inlet section between the material inlet and the nozzle.

Further, in the Venturi injector: the inner diameter of the material inlet is not less than 10 times the inner diameter of the nozzle.

Further, in the Venturi injector: the inner diameter of the mixing chamber is not less than the inner diameter of the nozzle, and is not greater than 2 times the inner diameter of the nozzle.

Further, in the Venturi injector: the length of the diffuser is not less than 30 times the length of the mixing chamber.

Further, in the Venturi injector: the angle between the inner wall of the diffuser and the axis of the diffuser is 7-15 degrees.

Further, in the Venturi injector: the ratio of the inner diameter of the material inlet, the inner diameter of the nozzle, the inner diameter of the mixing chamber, the length of the mixing chamber and the length of the diffuser is (38- 42): (2-3.5): (4-6): (25-40): (1300-1500).

Further, there are no baffles and cooling coils in the reaction kettle.

Furthermore, there are no stirring moving parts in the reaction kettle.

The device proposed by this utility model has at least one of the following advantages:

1. Improve the traditional process and synchronize the dehydration reaction and catalytic hydrogenation reaction in a reactor, shortening the process flow, reducing the investment in equipment, reducing the production cost of the product, and greatly reducing the side effects of the dehydration product. The probability of reaction increases the selectivity of the product.

2. Using an independent heat exchanger, the heat exchange area will not be limited, and the heat transfer energy efficiency is greater.

3. A Venturi ejector is installed on the top of the reactor to fully mix the materials and improve the reaction efficiency. There is no need to install baffles, stirring paddles and other components in the reactor, so the length-to-diameter ratio of the equipment is not limited and there is no movement in the internal space of the reactor. Parts with good airtight performance.

4. The continuous operation is convenient, the reaction yield is high, energy saving and environmental protection, and it is suitable for industrial production.

The above summary is for illustration purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present application will be readily apparent by reference to the drawings and the following detailed description.

Description of the drawings

In the drawings, unless otherwise specified, the same reference numbers refer to the same or similar parts or elements throughout the several figures. The drawings are not necessarily to scale. It should be understood that these drawings depict only some embodiments disclosed in accordance with the present application and should not be considered as limiting the scope of the present application.

Figure 1 is a schematic structural diagram of a device for preparing methyl isopentyl ketone of the present invention;

Figure 2 is a schematic structural diagram of a device for preparing methyl isopentyl ketone of the present invention;

Figure 3 is a schematic diagram of the filtration principle of the filter of the related technology and the present utility model;

Figure 4 is a partial structural schematic diagram of the Venturi injector used in the device for preparing methyl isopentyl ketone of the present invention.

Description of the drawings: 100-reactant mixer, 110-first reactant inlet, 120-dehydration catalyst inlet, 200-heat exchanger, 300-reaction kettle, 310-reducing gas inlet, 320-hydrogenation catalyst inlet, 330 -Material outlet, 340-Venturi injector, 341-Material inlet, 342-Inlet section, 343-Nozzle, 344-Mixing chamber, 345-Diffuser, 346-Air chamber, 350-Second reactant inlet, 400- Second reactant storage tank, 500-solid-liquid separation unit, 510-mixture inlet, 520-clean liquid product outlet, 530-slurry catalyst outlet, 540-metal membrane, 600-reducing gas buffer tank, 610-liquid product inlet , 620-gas vent, 630-methyl isoamyl ketone outlet, 640-purge gas outlet, 650-pressurized pipe, 660-balance pipe, 700-circulation pump, 800-hydrogen storage tank, 900-carrier gas storage tank.

Detailed ways

In the following, only certain exemplary embodiments are briefly described. As those skilled in the art would realize, the described embodiments may be modified in various different ways without departing from the spirit or scope of the application. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive.

The utility model provides a device for preparing methyl isoamyl ketone. Referring to Figures 1-4, the device includes a reactant mixer 100, a heat exchanger 200 and a reaction kettle 300. The reactant mixer 100 includes a first reactant inlet 110 and a dehydration catalyst inlet 120. The first reactant enters the reactant mixer 100 through the first reactant inlet 110, and the dehydration catalyst enters the reactant mixer 100 through the dehydration catalyst inlet 120. , the two are thoroughly mixed in the reactant mixer 100. The inlet of the heat exchanger 200 is connected to the outlet of the reactant mixer 100, and the reactants that are fully mixed by the reactant mixer 100 flow into the heat exchanger 200 for heating. The reactor 300 includes a venturi injector 340, a reducing gas inlet 310 and a hydrogenation catalyst inlet 320. The reducing gas and the hydrogenation catalyst are supplied to the reactor 300 through the reducing gas inlet 310 and the hydrogenation catalyst inlet 320 respectively. The venturi injector 340 is disposed on the top of the reactor 300 . The inlet of the Venturi injector 340 is connected to the outlet of the heat exchanger 200. The reactant heated by the heat exchanger 200 enters the Venturi injector 340. The second reactant inlet 350 is connected to the inlet of the Venturi injector 340. Reactants are also supplied from the second reactant inlet 350 to the inlet of the venturi injector 340 . For example, the second reactant can be separately pumped into the venturi injector 340 from the second reactant inlet 350 through a metering pump.

The device has at least one of the following beneficial effects: increasing product yield, reducing three waste emissions, lowering production costs, convenient continuous operation, high reaction yield, energy saving and environmental protection, and is suitable for industrial production.

In order to facilitate understanding, the following is a brief explanation of the principle by which the device can achieve the above beneficial effects:

This device is provided with a Venturi injector 340 inside the reactor 300, and the opening at the lower end of the Venturi injector 340 is connected to the internal space of the reactor 300. The reducing gas and the hydrogenation catalyst are supplied into the reactor 300 in advance, and the liquid reactants (including the first reactant, the second reactant and the dehydration catalyst) are supplied into the reactor 300 through the nozzle 343 of the Venturi injector 340 . Therefore, the Venturi injector 340 can be used to inject a high-speed flowing liquid, and the reducing gas can form fine bubbles through the shearing action of the high-speed liquid in the reactor 300, thus expanding the gas-liquid contact specific surface area and increasing the unit power consumption. mass transfer rate below. In general, this device can cause the reactant slurry in the reactor 300 to be intimately mixed with gas/liquid/solid, and complete the reaction at the moment the mixture is ejected from the nozzle 343 of the Venturi injector 340 to generate methyl. Isoamyl ketone.

Each unit and component of the device is described in further detail below:

Specifically, the device further includes a solid-liquid separation unit 500. The solid-liquid separation unit 500 includes a mixture inlet 510 , a clean liquid product outlet 520 and a slurry catalyst outlet 530 . The mixture inlet 510 is connected to the outlet of the heat exchanger 200 , and the slurry catalyst outlet 530 is connected to the inlet of the Venturi injector 340 .

A material outlet 330 is provided at the bottom of the reactor 300, and the material outlet 330 is connected to the inlet of the heat exchanger 200. The device further includes a circulation pump 700 to increase the flow rate between the reactor 300, the solid-liquid separation unit 500 and the heat exchanger 200. Pressure to form a material circulation loop. The circulation pump 700 can provide power for the circulation loop, extract part of the material from each outlet, and circulate part of the material in the aforementioned circulation loop. The liquid reactants (including the first reactant, the second reactant and the dehydration catalyst) can be injected into the reactor 300 through the Venturi injector 340, and the gas (including reducing gas) and solid (including the hydrogenation catalyst) reactants can be directly injected into the reactor 300. Supplied to the reaction kettle 300. Therefore, the solid-liquid separation unit 500 can be used to separate the solid-liquid-gas mixture in the reactor 300 from solid to liquid. The liquid product can be separated and then discharged, and the solid-containing slurry catalyst can be separated and then continuously supplied to the reactor 300 for recycling.

That is to say, at the beginning of the reaction, each reactant enters the internal space of the reactor 300 through the venturi injector 340 or the material inlet 341 on the reactor 300 to react and form a slurry mixture. The slurry mixture includes solid catalyst, liquid products and incompletely reacted liquid reactants, as well as dissolved gases (such as reducing gases such as hydrogen). The above-mentioned slurry mixture is discharged from the material outlet 330 and supplied to the heat exchanger 200 for heat exchange, and then supplied to the solid-liquid separation unit 500 through the mixture inlet 510 connected to the heat exchanger 200 for the aforementioned solid-liquid separation, thereby separating Clean liquid product and slurry catalyst are produced. The slurry catalyst obtained by solid-liquid separation includes a solid hydrogenation catalyst and a part of the liquid. The liquid may include unreacted liquid reactants and a small part of liquid products; the slurry catalyst is supplied to Venturi again from the slurry catalyst outlet 530 Injector 340, and then enter the reactor 300 for circulation. The clean liquid product obtained by solid-liquid separation is discharged from the solid-liquid separation unit 500 from the clean liquid product outlet 520 . This allows the material to circulate in the material circulation loop. This continuous reaction device forming a loop can shorten the residence time of materials and effectively avoid side reactions caused by the condensation of the reactants themselves.

What needs special explanation here is that in the present invention, the term "clean liquid product" should be understood in a broad sense, which means that this part of the material is a liquid mixture obtained after the solid hydrogenation catalyst is separated, which contains only a very small amount of hydrogenation catalyst. A small amount of solids, or a hydrogenation catalyst containing no solids. This term cannot be understood as meaning that the product does not contain impurities or incompletely reacted reactants.

In order to realize the aforementioned material circulation loop, a power component needs to be provided in the device to provide power for the aforementioned material circulation. For example, the power component may be a circulation pump 700. Since there is a closed material circulation loop between the reaction kettle 300, the heat exchanger 200 and the solid-liquid separation unit 500, it is only necessary to install the circulation pump 700 in this loop. For example, the circulation pump 700 is disposed in the pipeline between the material outlet 330 and the outlet of the heat exchanger 200 . In order to enable the circulation pump 700 to provide better power for the material circulation loop, the head of the circulation pump 700 is configured such that the pressure difference between the inlet and outlet of the circulation pump 700 is not less than 0.3MPa, and the circulation volume of the circulation pump 700 The volume of the reaction kettle 300 is 20 to 50 times, preferably 40 times. More specifically, the circulation volume of the circulation pump 700 is not less than the flow rate of 15m ³ /h, and the lift is preferably 15-30m, for example, it can be 20m, and a magnetic pump or a centrifugal pump can be used.

Specifically, the solid-liquid separation unit 500 may be a cross-flow filter. Referring to Figure 3, the cross-flow filter uses a metal membrane 540 as the filter medium, which can provide an inside-out or outside-in filtration form, and has the performance of providing a continuous filtration cycle through cross-flow filtration. As shown in (b) in Figure 3, driven by power components such as a pump, the slurry mixture entering the cross-flow filter flows parallel to the membrane surface of the metal film 540 (as shown by the horizontal arrows below) ). Different from the dead-end filtration shown in (a) of Figure 3, the shear force generated when the slurry mixture flows through the membrane surface can take away the solid particles retained on the membrane surface, thereby making the surface of the metal film 540 The pollution layer is kept at a thin level. The dead-end filtration shown in (a) in Figure 3, such as traditional plate and frame filtration, diatomaceous earth filtration, filter element filtration, etc., is driven by the pressure difference to cause the particles in the slurry mixture to be filtered by the metal film 540 'Intercepted. Therefore, as the filtration time increases, the trapped particles will form a pollution layer on the membrane surface, increasing the filtration resistance. When the operating pressure remains unchanged, the filtration permeability of the membrane will decrease significantly. Therefore, dead-end filtration can only be performed intermittently, and the contaminant layer on the membrane surface must be removed periodically or the membrane must be replaced. As a result, only intermittent filtration operations can be used, and continuous operation cannot be achieved.

Specifically, the material flow of the cross-flow filter (i.e., the slurry mixture) generates two component forces on the surface of the metal membrane 540. One is a reverse force perpendicular to the membrane surface, allowing the liquid material to pass through the membrane surface, and the other is The tangential force parallel to the membrane surface can wash away the trapped materials on the membrane surface, that is, solid materials. When the cross-flow filtration transmittance decreases, as long as the reverse force on the membrane surface is reduced and the tangential force on the membrane surface is increased, the metal membrane 540 can be effectively cleaned and the metal membrane 540 can restore its original performance. Therefore, the surface of the metal membrane 540 of the cross-flow filtration is constantly updated, which is less likely to cause concentration polarization and scaling problems, and the filtration transmittance decays slowly. Moreover, the entire filtration process mentioned above is only a solid-liquid separation process, which is a physical process and does not involve chemical reactions, so it will not affect the conversion rate and selectivity of raw materials.

To sum up, using a cross-flow filter as the solid-liquid separation unit 500 can filter the slurry catalyst online, thereby realizing the continuous reaction of the device and realizing the online recovery and application of the catalyst. That is to say, the solid-liquid separation unit 500 realizes online separation of the catalyst, so that the catalyst does not leave the system and always circulates to participate in the reaction.

Specifically, referring to Figure 4, the Venturi injector 340 is a high-performance gas-liquid mixing device, which includes a material inlet 341, a nozzle 343, a mixing chamber 344 and a diffuser 345 connected in sequence. The material inlet 341 is located in the reactor 300. The top is connected to the heat exchanger 200, and the lower end opening of the diffuser 345 is connected to the internal space of the reactor 300, where the material inlet 341 is the inlet of the Venturi ejector 340. Preferably, the lower end of the diffuser 345 extends into the liquid material below the reactor 300. There may also be an inlet section 342 between the material inlet 341 and the nozzle 343 to better form a high-speed mobile phase. The gas chamber 346 is connected with the mixing chamber 344 for the supply of gas. The material enters the Venturi injector 340 through the material inlet 341, and closely mixes gas/liquid/solid with the gas and solid catalyst (hydrogenation catalyst) introduced in the reactor 300, which can cause most of the reactions to occur in the nozzle 343 Partially complete, resulting in higher reaction efficiency.

The utility model forms a high-speed mobile phase through the Venturi ejector 340, and uses the high-speed mobile phase to entrain other phases in the reaction kettle 300, so that each phase is in close contact, and then a uniformly dispersed or suspended material mixture is formed in the reaction kettle 300. and complete the reaction. The applicant found that the key to influencing the reaction rate in this process is the mass transfer effect of the reaction. In traditional stirred tank reactors and loop reactors in related technologies, the diameter of the bubbles generated after the three-phase mixing of gas, liquid and solid is 1 to 2 mm. The average diameter of the bubbles formed by the Venturi ejector 340 can be less than 0.1 mm. The gas content volume ratio of the fluid in the reaction kettle 300 can reach a level of no less than 30%, thereby increasing the contact area between the gas and liquid phases, shortening the reaction time, significantly improving the reaction efficiency, increasing the production capacity, and reducing the production cost. cost.

Moreover, the reaction kettle 300 using the above-mentioned Venturi ejector 340 does not need to be equipped with baffles and cooling coils, and there are no stirring moving parts. As a result, the airtightness of the device can be further improved.

Specifically, the inner diameter D1 of the material inlet 341 can be made not less than 10 times the inner diameter D2 of the nozzle 343 . In some examples, the inner diameter D3 of the mixing chamber 344 can also be made not smaller than the inner diameter D2 of the nozzle 343 and not larger than twice the inner diameter D2 of the nozzle 343 . For example, the inner diameter D3 of the mixing chamber 344 can be made slightly larger than the inner diameter D2 of the nozzle 343 . In some examples, the length L2 of the diffuser 345 is no less than 30 times the length L1 of the mixing chamber 344. The diffuser 345 may be in the shape of a trumpet, and the angle between the inner wall of the diffuser 345 and the axis of the diffuser 345 may be 7-15 degrees. That is, the opening of the diffuser 345 has an included angle a, and the included angle a may be 15 to 30 degrees. What needs special explanation here is that the "opening angle a of the diffuser 345" means the angle between the straight lines in the extending direction of the two side walls in the cross-sectional view of the diffuser 345, as shown in Figure 4 of a.

Specifically, the ratio of the inner diameter D1 of the material inlet 341, the inner diameter D2 of the nozzle 343, the inner diameter D3 of the mixing chamber 344, the length L1 of the mixing chamber 344 and the length L2 of the diffuser 345 can be (38-42): (2-3.5) :(4-6)(25-40)(1300-1500). More specifically, the ratio of D1:D2:D3:L1:L2 may be 40:3:5:35:1400.

Using the Venturi ejector 340 with the above structure can form two circulation systems of materials in the reactor 300: one is driven by power components such as the circulation pump 700 and passes through the reactor 300, the heat exchanger 200 and the solid-liquid separation unit. 500 liquid circulation system; the second is a self-priming gas circulation system caused by the Venturi ejector 340. The unreacted gas will be separated from the liquid phase in the reactor 300 and collected at the top of the reactor 300. Then it is sucked back into the liquid phase by the air chamber 346 of the Venturi ejector 340.

Specifically, the reaction kettle 300 may be an elongated high-pressure reaction kettle. The aspect ratio of the reactor 300 is 2 to 8, which can facilitate heat dissipation of the reactor 300 and avoid unnecessary side reactions.

Specifically, the device further includes a reducing gas buffer tank 600 . The reducing gas buffer tank 600 includes a liquid product inlet 610, a methyl isoamyl ketone outlet 630, a purge gas outlet 640 and a gas vent 620. The liquid product inlet 610 is connected to the clean liquid product outlet 520 to supply the separated liquid product. The reduced gas buffer tank 600 is used for collection and gas-liquid separation, thereby separating the reducing gas dissolved in the liquid product. The separated liquid is the reaction product, which can be discharged from the methyl isoamyl ketone outlet 630 for collection, or enter subsequent sections for processing. It should be noted here that the methyl isoamyl ketone discharged from the methyl isoamyl ketone outlet 630 can be crude methyl isoamyl ketone, and the crude methyl isoamyl ketone can be formed after being processed in subsequent sections. Methyl Isoamyl Ketone Products. Alternatively, the crude methyl isoamyl ketone can be collected and supplied to a separate purification and impurity removal device for purification.

The gas vent 620 can vent hydrogen gas.

The purge gas outlet 640 is connected to the slurry catalyst outlet 530 . The reducing gas buffer tank 600 may also include a pressurizing pipe 650 through which hydrogen pressure compensation is performed to facilitate the purge gas outlet 640 connected to the slurry catalyst outlet 530 to purge the slurry catalyst to the Venturi injector. The reaction continues within 340 seconds.

The reducing gas buffer tank 600 can also be connected to the reaction kettle 300 . For example, the balance pipe 660 can be connected to the reactor 300, and the pressure pipe 650 can be in gas communication with the reactor 300 to stabilize the partial pressure of the reducing gas in the reactor 300.

Specifically, the device further includes a second reactant storage tank 400, a hydrogen storage tank 800, and a carrier gas storage tank 900, which can be used to continuously transport the reactants and gases required for the reaction into the reactor 300. For example, the second reactant storage tank 400 can be used to supply the second reactant to the reactor 300, such as isobutyraldehyde. The hydrogen storage tank 800 can provide reducing gas hydrogen, and the carrier gas storage tank 900 can provide inert carrier gases such as nitrogen and argon to replace the oxygen in the reactor 300 and the entire system to ensure that the oxygen content of the system is less than 0.5% to ensure safety.

Specifically, the device may have a metering pump for inputting liquid reactants and catalysts into the system in a certain proportion.

Specifically, the device can be used to synthesize products including, but not limited to, methyl isoamyl ketone based on acetone and isobutyraldehyde. It can also be used in product systems that require dehydration and hydrogenation reactions, have many side reactions, and are difficult to industrialize. For example, when the reactants themselves are prone to self-condensation, the reaction can be carried out in the form of a circulation loop in this application, so that the reactants can continuously circulate in the reaction device to avoid self-condensation and continue to react. This shortens the synthesis cycle, reduces the probability of side reactions, and increases product yield.

For ease of understanding, a brief description of the method for preparing methyl isopentyl ketone using the above device is given below. The method includes: premixing the first reactant and the dehydration catalyst in the reactant mixer 100, performing heat exchange treatment in the heat exchanger 200, and then transporting them to the Venturi injector 340. The second reactant is delivered from the second reactant inlet 350 to the venturi injector 340. The reducing gas and the hydrogenation catalyst are introduced into the reaction kettle 300 to carry out the reaction.

Specifically, the first reactant and the second reactant are used as raw materials, and under the action of a dehydration catalyst and a hydrogenation catalyst, methyl isoamyl ketone is continuously synthesized through dehydration and hydrogenation reactions in one step. The first reactant includes acetone, the dehydration catalyst includes alkali liquid, the second reactant includes isobutyraldehyde, the reducing gas includes hydrogen, and the hydrogenation catalyst includes a noble metal catalyst. For example, the precious metal catalyst may include palladium carbon, platinum carbon, nickel carbon and other catalysts, and specifically may be 1-5% (mass percentage based on the total mass of the catalyst containing the precious metal component) powdered palladium carbon catalyst. Correspondingly, the slurry catalyst may be a slurry palladium carbon catalyst.

Specifically, the reaction in the reactor 300 may be a hydrogenation reduction reaction, and more specifically, it may be a gas-liquid-solid three-phase total mixed reaction. For example, a metering pump can be used to pump the first reactant and the dehydration catalyst into the reactant mixer 100 in proportion, such as a static mixer. At the same time, the materials in the reactor 300 pass through the material outlet 330 at the bottom of the reactor 300. The circulation pump 700 between the pipeline of the heat exchanger 200 circulates and pressurizes, and pumps it into the inlet of the Venturi ejector 340. The Venturi ejector 340 mixes with the circulated catalyst-containing material to perform gas-liquid-solid three-phase mixing. reaction.

The main synthesis principle of methyl isopentyl ketone can include the following three steps:

1. Acetone and isobutyraldehyde undergo a cross-aldol condensation reaction via base catalysis to generate 4-hydroxy-5-methyl-2-hexanone.

2. 4-Hydroxy-5-methyl-2-hexanone undergoes dehydration reaction under the action of acidic catalyst to generate 5-methyl-3-hexen-2-one and 5-methyl-4-hexen-2-one. species isomers.

The two isomers 3.5-methyl-3-hexen-2-one and 5-methyl-4-hexen-2-one are catalytically hydrogenated under the action of a hydrogenation catalyst, both of which produce the target product 5- Methyl-2-hexanone, methyl isopentyl ketone.

Specifically, by using the aforementioned device to perform the above reaction, the dehydration reaction and the hydrogenation reaction can be performed simultaneously in the reactor 300, thereby achieving higher reaction efficiency. The aforementioned device has high heat transfer and mass transfer efficiency, which can also increase the selectivity of the reaction. Moreover, the mass production cycle can be shortened.

Specifically, referring to Figure 2, acetone and isobutyraldehyde can be supplied to the Venturi injector 340 at a molar ratio of (3-5):1, and simultaneous dehydration occurs under the action of the dehydration catalyst and the hydrogenation catalyst. reaction and hydrogenation reaction. The temperature of the reaction can be lower, specifically, it can be 80-100°C.

Specifically, the method includes: discharging the material in the reactor 300 from the material outlet 330, mixing it with the premixed first reactant and the dehydration catalyst, for example, under the pressure of the circulation pump 700, and supplying it to the heat exchanger. 200. The material heat exchanged by the heat exchanger 200 is supplied to the solid-liquid separation unit 500 for solid-liquid separation processing to obtain a clean liquid product and a slurry catalyst. The clean liquid product is discharged from the solid-liquid separation unit 500 and the slurry catalyst is supplied to the Venturi The injector 340 performs a loop reaction. For example, specifically, the material discharged from the bottom of the reaction kettle 300 passes through a cross-flow filter that can retain the solid hydrogenation catalyst, and the clean liquid product obtained enters the reducing gas buffer at a flow rate of 80-150L/h, for example, a flow rate of 100L/h. After the tank 600, it is extracted outward, and after cooling and other processing, it enters the product intermediate storage tank for storage and collection.

During the reaction process, the fluid linear velocity at the nozzle 343 of the Venturi injector 340 can be controlled to be 80-120 m/s, for example, it can be 100 m/s. Materials with the above-mentioned fluid linear velocity can form the aforementioned high-speed fluid, which can further promote the mixing of solid, liquid and gas phases and improve reaction efficiency. The opening of the diffuser 345 of the Venturi ejector 340 can also be positioned below the liquid level of the liquid in the reactor 300, thereby forming turbulence and pushing the reaction endpoint further.

Specifically, the clean liquid product produced through the solid-liquid separation process is supplied to the reducing gas buffer tank 600 for gas-liquid separation to obtain the methyl isoamyl ketone product and separate the reducing gas. For example, the reducing gas may be hydrogen.

Specifically, the method further includes at least one of the following processes: the reducing gas buffer tank 600 is connected to the reaction kettle 300 through the balance pipe 660, and the gas supplied from the reducing gas buffer tank 600 to the reaction kettle 300 is controlled to stabilize the reaction kettle 300. partial pressure of reducing gas. The reducing gas buffer tank 600 further includes a purge gas outlet 640 , which is connected to the solid-liquid separation unit 500 to purge the slurry-containing catalyst into the Venturi injector 340 . The pressurizing pipe 650 is used to perform hydrogen pressure compensation in the reducing gas buffer tank 600 .

More specifically, the pressure compensation can be to close the vent valve on the reducing gas buffer tank 600 every 1 to 3 hours, and use hydrogen to increase the pressure of the reducing gas buffer tank 600 so that its pressure is higher than the pressure of the reaction kettle 300. The pressure difference between the two is not less than 0.3MPa. Then open the bottom valve of the reducing gas buffer tank 600 to backwash the cross-flow filter.

Specifically, the method may specifically include:

In the ^1m3 reaction kettle 300, the carrier gas is sent into the reaction kettle 300 and replaced repeatedly 2 to 3 times until the oxygen content is qualified, and then acetone and 10% sodium hydroxide solution are pumped into the reactant mixer 100 respectively. , simultaneously sending isobutyraldehyde and hydrogen into the reaction kettle 300. The ratio of the reactants has been described in detail before and will not be repeated here. Control the gas flow, raise the system pressure to 0.3MPa, check all valves on the circulation loop to ensure normal circulation, and then start the circulation pump 700 to circulate the reactants in the reactor 300, the heat exchanger 200, and the solid-liquid separation unit 500. .

In general, the device for preparing methyl isoamyl ketone proposed by the utility model uses isobutyraldehyde and acetone as reactants, and under the action of a dehydration catalyst and a hydrogenation catalyst, it undergoes a one-step dehydration and hydrogenation reaction. Continuous synthesis of methyl isopentyl ketone. Since the dehydration catalyst is not easily soluble in the first reactant and the second reactant, a large amount of water needs to be added for the reaction to proceed smoothly. In addition, the product obtained through the dehydration reaction is insoluble in water, causing the water and oil phases to gradually form in the system, and even reactants may precipitate, requiring strong stirring. The utility model utilizes the circulating reaction loop formed by the circulating pump 700 between the reaction kettle 300, the heat exchanger 200 and the solid-liquid separation unit 500 to effectively avoid the side reaction of the reactant's self-condensation, and can achieve this at a lower reaction temperature. Satisfactory conversion rate and selectivity. The reaction mainly occurs in the nozzle 343 of the Venturi injector 340. By controlling the residence time in the reaction zone of the nozzle 343, the conversion rate of the reaction and the selectivity of the product can be improved. Through selective hydrogenation, the yield of the product is increased, the emission of three wastes is reduced, and the production cost is reduced. The utility model has convenient continuous operation, high reaction yield, energy saving and environmental protection, and is suitable for industrialization.

The basic principles and main features of the present utility model and the advantages of the present utility model have been shown and described above. For those skilled in the art, it is obvious that the present utility model is not limited to the details of the above exemplary embodiments, and does not deviate from the present utility model. Without the spirit or basic characteristics of the invention, the present invention can be implemented in other specific forms. Accordingly, the embodiments should be considered illustrative and not restrictive in any respect.

In addition, it should be understood that although this specification is described in terms of implementations, not each implementation only contains an independent technical solution. This description of the specification is only for the sake of clarity, and those skilled in the art should take the specification as a whole. , the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims (10)

1. A device for preparing methyl isoamyl ketone, characterized in that the device includes a reactant mixer, a heat exchanger and a reaction kettle; The reactant mixer includes a first reactant inlet and a dehydration catalyst inlet; The inlet of the heat exchanger is connected to the outlet of the reactant mixer; The reaction kettle includes a Venturi ejector, a reducing gas inlet and a hydrogenation catalyst inlet; The Venturi ejector is located at the top of the reaction kettle, the inlet of the Venturi ejector is connected to the outlet of the heat exchanger, and the second reactant inlet is connected to the inlet of the Venturi ejector. 2. The device according to claim 1, characterized in that the device includes a solid-liquid separation unit, the solid-liquid separation unit includes a mixture inlet, a clean liquid product outlet and a slurry catalyst outlet, the mixture inlet and the The outlet of the heat exchanger is connected, and the outlet of the slurry catalyst is connected with the inlet of the Venturi injector. 3. The device according to claim 2, characterized in that a material outlet is provided at the bottom of the reaction kettle, and the material outlet is connected to the inlet of the heat exchanger, and the device further includes a circulation pump to A material circulation loop is formed between the reaction kettle, the solid-liquid separation unit and the heat exchanger. 4. The device according to claim 3, characterized in that the circulation pump meets at least one of the following conditions: The circulation pump is located in the pipeline between the material outlet and the outlet of the heat exchanger; The head of the circulation pump is configured such that the pressure difference between the inlet and outlet of the circulation pump is not less than 0.3MPa; The circulation volume of the circulation pump is 20 to 50 times the volume of the reaction kettle. 5. The device according to claim 2, wherein the solid-liquid separation unit is a cross-flow filter. 6. The device according to claim 2, characterized in that the device includes a reducing gas buffer tank; The reducing gas buffer tank includes a liquid product inlet, a methyl isoamyl ketone outlet, a purge gas outlet and a gas vent; wherein the liquid product inlet is connected to the clean liquid product outlet, and the purge gas outlet Connected to the outlet of the slurry catalyst; The reducing gas buffer tank and the reaction kettle are connected through a balance pipe; The reducing gas buffer tank further includes a pressurized tube. 7. The device according to claim 1, characterized in that the aspect ratio of the reaction kettle is 2-8. 8. The device according to claim 1, wherein the Venturi injector includes a material inlet, a nozzle, a mixing chamber and a diffuser connected in sequence, and has an air chamber connected to the mixing chamber, the The material inlet is located at the top of the reaction kettle, and the material inlet is connected to the outlet of the heat exchanger, and the opening of the diffuser faces the inside of the reaction kettle. 9. The device according to claim 8, wherein the Venturi injector meets at least one of the following conditions: There is an inlet section between the material inlet and the nozzle; The inner diameter of the material inlet is not less than 10 times the inner diameter of the nozzle; The inner diameter of the mixing chamber is not less than the inner diameter of the nozzle, and not greater than 2 times the inner diameter of the nozzle; The length of the diffuser is not less than 30 times the length of the mixing chamber; The angle between the inner wall of the diffuser and the axis of the diffuser is 7-15 degrees; The ratio of the inner diameter of the material inlet, the inner diameter of the nozzle, the inner diameter of the mixing chamber, the length of the mixing chamber and the length of the diffuser is (38-42): (2-3.5): (4 -6): (25-40): (1300-1500). 10. The device according to any one of claims 1 to 9, characterized in that there are no baffles and cooling coils in the reaction kettle; And/or, there are no stirring moving parts in the reaction kettle.