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

Device for preparing methyl isoamyl ketone

Technical Field

The utility model relates to the technical field of organic synthesis, in particular to a device for preparing methyl isoamyl ketone.

Background

Methyl isoamyl ketone (Methyl Isoamyl Ketone is abbreviated as MIAK), the chemical name is 5-methyl-2-hexanone, and the methyl isoamyl ketone is colorless transparent liquid with light fragrance. Mainly used as solvents for cellulose acetate, acrylic resins, polyvinyl formal resins and the like. Can also be used for organic synthesis, and is a main raw material for preparing p-phenylenediamine rubber antioxidant 7PPD, 77PD and TMPPD. However, the industrial device for methyl isoamyl ketone is generally synthesized by adopting a batch kettle type two-step method or a one-step method at present. Under the action of catalyst, the reactant is condensed, dehydrated and hydrogenated to produce methyl isoamyl ketone. However, the industrial device and the synthesis method of methyl isoamyl ketone used in the related art have a plurality of defects: the catalyst has poor catalytic activity, low reactant conversion rate, poor selectivity, low product purity, more side reactions, more synthesis steps, complex process, strong equipment corrosiveness and large amount of waste liquid production, and is not suitable for industrial production.

Thus, there is a need for an improved apparatus for preparing methyl isoamyl ketone.

Disclosure of Invention

In view of the shortcomings of the prior art, the present utility model aims to provide an apparatus for preparing methyl isoamyl ketone, which solves the problems set forth in the background art.

The present utility model provides an apparatus for preparing methyl isoamyl ketone comprising: reactant mixer, heat exchanger and reaction kettle; the reactant mixer includes a first reactant inlet and a dehydration catalyst inlet to mix the first reactant and the dehydration catalyst; an inlet of the heat exchanger is connected with an outlet of the reactant mixer so as to heat the mixed reactant; 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.

Further, the apparatus includes a solid-liquid separation unit including a mixture inlet, a clean liquid product outlet, and a slurry catalyst outlet, the mixture inlet being coupled to the outlet of the heat exchanger, the slurry catalyst outlet being coupled to the inlet of the venturi eductor.

Still further, the reactor bottom is equipped with the material export, the material export with the entry of heat exchanger links to each other, the device further includes the circulating pump, in order to form the material circulation loop between the reactor, solid-liquid separation unit and the heat exchanger.

The circulating pump is arranged in a pipeline between the material outlet and the outlet of the heat exchanger.

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

Still further, the circulation amount of the circulation pump is 20 to 50 times of the volume of the reaction kettle.

Still further, the circulating pump is a magnetic pump or a centrifugal pump.

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

Further, the device also comprises a reducing gas buffer tank; the reducing gas buffer tank comprises 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 is connected to the slurry catalyst outlet to purge the slurry catalyst into the venturi eductor.

Further, the reducing gas buffer tank is connected with the reaction kettle through a balance pipe so as to stabilize the partial pressure of the reducing gas in the reaction kettle.

Still further, the reducing gas buffer tank further includes a pressurizing pipe to compensate for hydrogen pressurization within the reducing gas buffer tank.

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

Further, the venturi ejector comprises a material inlet, a nozzle, a mixing chamber and a diffuser which are sequentially connected, and is provided with an air chamber communicated with the mixing chamber, wherein the material inlet is positioned at the top of the reaction kettle, the material inlet is connected with an outlet of the heat exchanger, and an opening of the diffuser faces the inside of the reaction kettle.

Further, in the venturi injector: an inlet section is arranged 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 of the inner diameter of the nozzle.

Further, in the venturi injector: the inner diameter of the mixing chamber is not smaller than the inner diameter of the nozzle and is not larger 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 included 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, no baffle plate and no cooling coil are arranged in the reaction kettle.

Further, the reaction kettle is internally provided with no stirring moving part.

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

1. the traditional process is improved, the dehydration reaction and the catalytic hydrogenation reaction are synchronously carried out in one reactor, the process flow is shortened, the investment on equipment is reduced, the production cost of products is reduced, the probability of side reactions of the dehydrated products is greatly reduced, and the selectivity of the products is improved.

2. By adopting the independent heat exchanger, the heat exchange area is not limited, and the heat transfer energy efficiency is larger.

3. The venturi ejector is arranged at the top of the reaction kettle, so that materials can be fully mixed, the reaction efficiency is improved, the components such as a baffle plate and a stirring paddle are not required to be arranged in the reaction kettle, the length-diameter ratio of the equipment is not limited, no moving component exists in the inner space of the reaction kettle, and the air tightness performance is good.

4. The continuous operation is convenient, the reaction yield is high, the energy is saved, the environment is protected, and the method is suitable for industrial production.

The foregoing summary is for the purpose of the specification 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 become apparent by reference to the drawings and the following detailed description.

Drawings

In the drawings, the same reference numerals refer to the same or similar parts or elements throughout the several views unless otherwise specified. The figures are not necessarily drawn to scale. It is appreciated that these drawings depict only some embodiments according to the disclosure and are not therefore to be considered limiting of its scope.

FIG. 1 is a schematic structural diagram of an apparatus for preparing methyl isoamyl ketone according to the present utility model;

FIG. 2 is a schematic structural view of an apparatus for preparing methyl isoamyl ketone according to the present utility model;

FIG. 3 is a schematic diagram of the filtering principle of the related art and the filter of the present utility model;

fig. 4 is a schematic view of a portion of a venturi eductor for use in the apparatus for producing methyl isoamyl ketone of the present utility model.

Description of the drawings: 100-reactant mixer, 110-first reactant inlet, 120-dehydration catalyst inlet, 200-heat exchanger, 300-reaction vessel, 310-reducing gas inlet, 320-hydrogenation catalyst inlet, 330-feed outlet, 340-venturi eductor, 341-feed inlet, 342-inlet section, 343-nozzle, 344-mixing chamber, 345-diffuser, 346-plenum, 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-pressurization tube, 660-equalization tube, 700-circulation pump, 800-hydrogen storage tank, 900-storage tank.

Detailed Description

Hereinafter, only certain exemplary embodiments are briefly described. As will be recognized by those of skill in the pertinent art, the described embodiments may be modified in various different ways without departing from the spirit or scope of the present application. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive.

The present utility model provides an apparatus for preparing methyl isoamyl ketone. Referring to fig. 1 to 4, the apparatus 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 entering the reactant mixer 100 from the first reactant inlet 110, and the dehydration catalyst entering the reactant mixer 100 from the dehydration catalyst inlet 120, both of which 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 reactant well mixed by the reactant mixer 100 flows into the heat exchanger 200 to be heated. The reaction vessel 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 reaction vessel 300 through a reducing gas inlet 310 and a hydrogenation catalyst inlet 320, respectively. A venturi eductor 340 is provided at the top of the reaction kettle 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, and the second reactant is also supplied from the second reactant inlet 350 to the inlet of the venturi injector 340. For example, the second reactant may be separately injected into the venturi injector 340 from the second reactant inlet 350 via a metering pump.

The device has at least one of the following advantages: 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.

For easy understanding, the principle by which the device can achieve the above-described beneficial effects is first briefly described below:

the device is provided with a venturi ejector 340 in the reaction kettle 300, and an opening at the lower end of the venturi ejector 340 is communicated with the internal space of the reaction kettle 300. The reducing gas and the hydrogenation catalyst are supplied into the reaction kettle 300 in advance, and the liquid reactant (including the first reactant, the second reactant, and the dehydration catalyst) is supplied into the reaction kettle 300 through the nozzle 343 of the venturi injector 340. The venturi injector 340 can be used for injecting liquid flowing at high speed, and the reducing gas can form tiny bubbles in the reaction kettle 300 under the shearing action of the liquid at high speed, so that the gas-liquid contact specific surface area is enlarged, and the mass transfer rate under unit power consumption is improved. In general, the apparatus provides for intimate mixing of the reactant slurry in the reaction vessel 300 to produce gas/liquid/solid and complete the reaction at the instant the mixture is ejected from the nozzle 343 of the venturi ejector 340 to produce methyl isoamyl ketone.

The individual units and components of the device are described in further detail below:

specifically, the apparatus 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 being connected to the outlet of the heat exchanger 200, the slurry catalyst outlet 530 being connected to the inlet of the venturi injector 340.

The reaction kettle 300 is provided with a material outlet 330 at the bottom, the material outlet 330 is connected with the inlet of the heat exchanger 200, and the apparatus further comprises a circulating pump 700 to pressurize the material between the reaction kettle 300, the solid-liquid separation unit 500 and the heat exchanger 200 to form a material circulation loop. The circulation pump 700 may power the circulation loop to draw a portion of the material from each outlet and circulate a portion of the material in the circulation loop as described above. Liquid reactants (including the first reactant, the second reactant, and the dehydration catalyst) may be injected into the reaction vessel 300 through the venturi injector 340, and gas (including a reducing gas) and solid (including a hydrogenation catalyst) reactants may be directly supplied into the reaction vessel 300. Therefore, the solid-liquid separation unit 500 can be used to separate the solid, liquid and gas in the reaction kettle 300, the liquid product can be discharged after separation, and the slurry catalyst containing the solid can be continuously supplied to the reaction kettle 300 for recycling after separation.

That is, at the beginning of the reaction, each reactant enters the inner space of the reaction vessel 300 through the venturi injector 340 or the material inlet 341 of the reaction vessel 300 to react and form a slurry mixture. The slurry mixture includes solid catalyst, liquid product and unreacted liquid reactant, and dissolved gas (e.g., reducing gas such as hydrogen). The slurry mixture is discharged from the material outlet 330 and supplied to the heat exchanger 200 to exchange heat, and then supplied to the solid-liquid separation unit 500 through the mixture inlet 510 connected to the heat exchanger 200 to perform the aforementioned solid-liquid separation, thereby separating a clean liquid product and a slurry catalyst. The slurry catalyst obtained by solid-liquid separation comprises a solid hydrogenation catalyst and a part of liquid, wherein the liquid can comprise unreacted complete liquid reactant and a small part of liquid product; the slurry catalyst is supplied again from the slurry catalyst outlet 530 to the venturi eductor 340 and further enters the reaction vessel 300 for circulation. The clean liquid product obtained by the solid-liquid separation is discharged from the solid-liquid separation unit 500 through the self-cleaning liquid product outlet 520. Thereby causing the material to circulate within the material circulation loop. The continuous reaction device for forming the loop can shorten the material residence time and effectively avoid side reactions of the self-condensation of reactants.

It is specifically stated herein that in the present utility model the term "clean liquid product" is to be understood in a broad sense in the sense that the portion of material is the liquid mixture obtained after separation of the solid hydrogenation catalyst is achieved, with little or no solid hydrogenation catalyst. The term should not be construed as implying that the product contains no impurities or unreacted reactants.

In order to realize the material circulation loop, a power component is required to be arranged in the device so as to provide power for the material circulation. For example, the power component may be the circulation pump 700. Since a closed material circulation circuit is provided among the reaction vessel 300, the heat exchanger 200, and the solid-liquid separation unit 500, the circulation pump 700 may be provided in the circuit. For example, the circulation pump 700 is provided in a line between the material outlet 330 and the outlet of the heat exchanger 200. In order that the circulation pump 700 can provide better power for the material circulation loop, the lift of the circulation pump 700 is configured such that the pressure difference between the inlet and the outlet of the circulation pump 700 is not less than 0.3MPa, and the circulation amount of the circulation pump 700 is 20 to 50 times, preferably 40 times, the volume of the reaction kettle 300. More specifically, the circulation amount of the circulation pump 700 is not lower than 15m of the flow rate ³ Preferably, the lift is 15-30m, for example, 20m, and a magnetic pump or a centrifugal pump can be used.

In particular, the solid-liquid separation unit 500 may be a cross-flow filter in particular. Referring to fig. 3, the cross-flow filter using a metal membrane 540 as a filter medium may provide an inside-out or outside-in filtration format with the ability to provide a continuous filtration cycle through cross-flow filtration. As shown in fig. 3 (b), the slurry mixture entering the cross flow filter flows parallel to the membrane surface of the metal membrane 540 (as shown by the lateral arrows in the following) under the pushing of a power component such as a pump. Unlike dead-end filtration shown in fig. 3 (a), the shear force generated by the slurry mixture flowing through the membrane surface can carry away solid particles retained on the membrane surface, thereby maintaining a thin level of fouling on the surface of the metal membrane 540. The dead-end filtration, such as conventional plate-and-frame filtration, diatomaceous earth filtration, cartridge filtration, etc., shown in fig. 3 (a) is performed by trapping particles in the slurry mixture by the metal film 540' under the pushing of the pressure difference. Thus, as the filtration time increases, the trapped particles will form a fouling layer on the membrane surface, increasing the filtration resistance. The filtration transmittance of the membrane will drop significantly with the operating pressure unchanged. Thus, dead-end filtration can only be performed intermittently, and the membrane surface must be periodically cleaned of contaminant layers or replaced. This in turn results in that only intermittent filtration operation can be employed and continuous operation cannot be achieved.

Specifically, the flow of material (i.e., slurry mixture) through the cross-flow filter creates two force components on the surface of metal membrane 540, one being a counter force perpendicular to the membrane surface, allowing liquid material to pass through the membrane surface, and the other being a tangential force parallel to the membrane surface, allowing the retentate, i.e., solid material, of the membrane surface to be flushed away. When the cross-flow filtration transmittance is reduced, the metal film 540 can be effectively cleaned only by reducing the reverse force of the film surface and improving the tangential force of the film surface, so that the original performance of the metal film 540 is recovered. Therefore, the surface of the metal film 540 for cross-flow filtration is continuously updated, so that concentration polarization phenomenon and scaling problem are not easy to occur, and the filtration transmittance is reduced slowly. The whole filtering process is only a solid-liquid separation process, belongs to a physical process, and does not involve chemical reaction, so that the conversion rate and selectivity of raw materials are not affected.

In summary, the cross-flow filter is adopted as the solid-liquid separation unit 500, so that the slurry catalyst can be filtered on line, the continuous reaction of the device is further realized, and the on-line recovery and application of the catalyst are realized. That is, the on-line separation of the catalyst is realized by the solid-liquid separation unit 500, so that the catalyst does not leave the system and always participates in the reaction in a circulating manner.

Specifically, referring to fig. 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, wherein the material inlet 341 is positioned at the top of the reaction vessel 300 and connected to the heat exchanger 200, and the lower end opening of the diffuser 345 is communicated with the inner space of the reaction vessel 300, wherein the material inlet 341 is the inlet of the venturi injector 340. Preferably, the lower end of the diffuser 345 extends into the liquid material below the reactor 300. An inlet section 342 may also be provided between the material inlet 341 and the nozzle 343 to better form a high velocity mobile phase. The gas chamber 346 communicates with the mixing chamber 344 for the supply of gas. The materials enter the venturi injector 340 through the material inlet 341 and are intimately mixed with the gas and the solid catalyst (hydrogenation catalyst) introduced into the reaction kettle 300 to generate gas/liquid/solid, so that most of the reaction can be completely performed at the nozzle 343, thereby having higher reaction efficiency.

The present utility model forms a high-velocity mobile phase through the venturi injector 340 and draws other phases in the reaction vessel 300 by using the high-velocity mobile phase to closely contact the phases, thereby forming a uniformly dispersed or suspended material mixture in the reaction vessel 300 and completing the reaction. Applicants have found that influencing the reaction rate in this process is critical to the mass transfer effect of the reaction. In the conventional stirred tank reactor and the loop reactor in the related art, the diameter of the generated bubbles after the gas, liquid and solid phases are mixed is 1-2 mm, and the average diameter of the bubbles formed by the venturi injector 340 may be less than 0.1mm. The volume ratio of the gas content of the fluid in the reaction kettle 300 can reach a level not lower than 30%, so that the contact area between the gas phase and the liquid phase is increased, the reaction time is shortened, the reaction efficiency is obviously improved, the production capacity is improved, and the production cost is reduced.

In addition, the reaction kettle 300 using the venturi injector 340 does not need to be provided with a baffle plate and a cooling coil pipe, and does not have stirring moving parts. Thereby, the air tightness of the device can be further improved.

Specifically, the inner diameter D1 of the material inlet 341 may 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 may also be made not smaller than the inner diameter D2 of the nozzle 343 and not larger than 2 times the inner diameter D2 of the nozzle 343. For example, the inner diameter D3 of the mixing chamber 344 may be made slightly larger than the inner diameter D2 of the nozzle 343. In some examples, the length L2 of the diffuser 345 is not less than 30 times the length L1 of the mixing chamber 344. The diffuser 345 may be flared and the inner wall of the diffuser 345 may be at an angle of 7-15 degrees to the axis of the diffuser 345. I.e., the opening of the diffuser 345 has an included angle a, which may be 15-30 degrees. It should be specifically noted that, the "opening angle a of the diffuser 345" means an angle between straight lines of the extending directions of the two sidewalls in a cross-sectional view of the diffuser 345, as shown as a in fig. 4.

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 may 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.

The venturi ejector 340 having the above-described structure can form two circulation systems of materials in the reaction tank 300: one is a liquid circulation system driven by power components such as a circulation pump 700 and the like and passing through the reaction kettle 300, the heat exchanger 200 and the solid-liquid separation unit 500; the second is a self-priming gas circulation system caused by the venturi eductor 340, and unreacted gas will be separated from the liquid phase in the reactor 300, collected at the top of the reactor 300, and then sucked back into the liquid phase by the plenum 346 of the venturi eductor 340.

Specifically, the reaction vessel 300 may be an elongated autoclave. The aspect ratio of the reaction kettle 300 is 2-8, which is beneficial to heat dissipation of the reaction kettle 300 and avoids unnecessary side reactions.

Specifically, the apparatus 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, and the liquid product inlet 610 is connected to a clean liquid product outlet 520 to supply the separated liquid product to the reducing gas buffer tank 600 for collection and gas-liquid separation to separate the reducing gas dissolved in the liquid product. The separated liquid is the reaction product and can be discharged from the methyl isoamyl ketone outlet 630 for collection or can be processed in a subsequent process. It is specifically contemplated herein that the methyl isoamyl ketone exiting methyl isoamyl ketone outlet 630 may be crude methyl isoamyl ketone which may be processed in a subsequent stage to form a methyl isoamyl ketone product. Alternatively, the crude methyl isoamyl ketone may be fed to a separate purification and impurity removal unit for purification after collection.

The gas vent 620 may allow for hydrogen venting.

Purge gas outlet 640 is connected to slurry catalyst outlet 530. The reducing gas surge tank 600 may also include a pressurization pipe 650, through which hydrogen pressurization compensation is performed by the pressurization pipe 650 to facilitate purging the slurry catalyst into the venturi injector 340 for further reaction by the purge gas outlet 640 connected to the slurry catalyst outlet 530.

The reducing gas buffer tank 600 may also be connected to the reaction vessel 300. For example, the reaction vessel 300 may be connected through a balance pipe 660, and in gas communication with the reaction vessel 300 by a pressurizing pipe 650, to stabilize the partial pressure of the reducing gas in the reaction vessel 300.

Specifically, the apparatus further comprises a second reactant storage tank 400, a hydrogen storage tank 800, and a carrier gas storage tank 900, which can be used to continuously feed reactants and gases required for the reaction into the reaction vessel 300. For example, the second reactant reservoir 400 may be used to supply a second reactant, which may be isobutyraldehyde, for example, to the reaction tank 300. The hydrogen storage tank 800 can provide reducing gas hydrogen, the carrier gas storage tank 900 can provide inert carrier gases such as nitrogen, argon and the like, the oxygen of the reaction kettle 300 and the whole system is replaced, the oxygen content of the system is ensured to be lower than 0.5%, and the safety is ensured.

In particular, the device may have a metering pump for feeding liquid reactants and catalyst into the system in a certain proportion.

In particular, the apparatus may be used for products including, but not limited to, the synthesis of methyl isoamyl ketone based on acetone and isobutyraldehyde. Can also be used for a product system which needs dehydration and hydrogenation reactions, has more side reactions and is difficult to industrially produce. For example, in the case where the reactant itself is liable to self-condensation, the reaction may be carried out in the form of a circulation circuit in the present application, so that the reactant continuously circulates in the reaction apparatus, and the self-condensation is avoided, and the reaction is continuously carried out. Thereby shortening the synthesis period, reducing the occurrence probability of side reactions and improving the product yield.

For ease of understanding, a brief description of the process for preparing methyl isoamyl ketone using the apparatus described above is provided below. The method comprises the following steps: the first reactant and the dehydration catalyst are premixed in the reactant mixer 100, subjected to heat exchange treatment by the heat exchanger 200, and then transferred to the venturi injector 340. The second reactant is delivered from the second reactant inlet 350 to the venturi injector 340. A reducing gas and a hydrogenation catalyst are introduced into the reaction vessel 300 to perform a reaction.

Specifically, the methyl isoamyl ketone is continuously synthesized by taking a first reactant and a second reactant as raw materials through dehydration and hydrogenation reaction in one step under the action of a dehydration catalyst and a hydrogenation catalyst. The first reactant comprises acetone, the dehydration catalyst comprises an alkaline solution, the second reactant comprises isobutyraldehyde, the reducing gas comprises hydrogen, and the hydrogenation catalyst comprises a noble metal catalyst. For example, the noble metal catalyst may include palladium carbon, platinum carbon, nickel carbon, etc., and may specifically be 1 to 5% (mass percent of the noble metal component contained based on the total mass of the catalyst) of powdered palladium carbon catalyst. Accordingly, the slurry catalyst may be a slurry palladium on carbon catalyst.

Specifically, the reaction in the reaction kettle 300 may be a hydrogenation reduction reaction, and more specifically, may be a gas-liquid-solid three-phase total mixed reaction. For example, the first reactant and the dehydration catalyst may be pumped into the reactant mixer 100, such as a static mixer, by a metering pump, etc., while the material in the reaction vessel 300 is circularly pressurized through the material outlet 330 at the bottom of the reaction vessel via the circulating pump 700 between the reaction vessel 300 and the pipeline of the heat exchanger 200, pumped into the inlet of the venturi injector 340, and mixed with the circulated material containing the catalyst via the venturi injector 340, to perform a gas-liquid-solid three-phase mixing reaction.

The main synthetic principle of methyl isoamyl ketone may include the following three steps:

1. the acetone and the isobutyraldehyde are catalyzed by alkali to carry out cross aldol condensation reaction to generate 4-hydroxy-5-methyl-2-hexanone.

And 2.4-hydroxy-5-methyl-2-hexanone is dehydrated under the action of an acid catalyst to generate two isomers of 5-methyl-3-hexene-2-ketone and 5-methyl-4-hexene-2-ketone.

3.5-methyl-3-hexene-2-ketone and 5-methyl-4-hexene-2-ketone, both of which are subjected to catalytic hydrogenation under the action of a hydrogenation catalyst, so as to generate the target product 5-methyl-2-hexanone, namely methyl isoamyl ketone.

Specifically, the dehydration reaction and the hydrogenation reaction can be synchronously performed in the reaction kettle 300 by adopting the device, so that the reaction efficiency is high. The device has higher heat and mass transfer efficiency, and further can increase the selectivity of the reaction. In addition, the mass production period can be shortened.

Specifically, referring to fig. 2, the molar ratio may be (3-5): 1, acetone and isobutyraldehyde are supplied to the venturi eductor 340, and dehydration reaction and hydrogenation reaction are simultaneously performed by the dehydration catalyst and hydrogenation catalyst. The temperature of the reaction may be low, and in particular, may be 80-100 ℃.

Specifically, the method comprises the following steps: the materials in the reaction vessel 300 are discharged from the material outlet 330, and are mixed with the pre-mixed first reactant and the dehydration catalyst, for example, by pressurizing the circulation pump 700, and then supplied to the heat exchanger 200. The material subjected to heat exchange by the heat exchanger 200 is supplied to the solid-liquid separation unit 500 to be subjected to solid-liquid separation treatment 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 injector 340 to be subjected to cyclic reaction. For example, specifically, the materials discharged from the bottom of the reaction kettle 300 can retain the solid hydrogenation catalyst through a cross-flow filter, and the obtained clean liquid product enters the reducing gas buffer tank 600 at a flow rate of 80-150L/h, for example, specifically 100L/h, is extracted outwards, and enters a product intermediate storage tank for storage and collection through cooling and the like.

During the reaction, the linear velocity of the fluid at the nozzle 343 of the venturi injector 340 may be controlled to 80-120m/s, for example, 100m/s. The material with the fluid linear velocity can form the high-speed fluid, so that the mixing of solid, liquid and gas phases can be promoted, and the reaction efficiency is improved. The openings of the diffuser 345 of the venturi injector 340 may be positioned below the level of the liquid in the reactor 300, thereby creating turbulence and further pushing the end point of the reaction.

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

Specifically, the method further comprises at least one of the following treatments: the reducing gas buffer tank 600 is connected to the reaction vessel 300 through the balance pipe 660, and the gas supplied from the reducing gas buffer tank 600 to the reaction vessel 300 is controlled to stabilize the partial pressure of the reducing gas in the reaction vessel 300. The reducing gas surge tank 600 further includes a purge gas outlet 640, the purge gas outlet 640 being connected to the solid-liquid separation unit 500 to purge the slurry-containing catalyst into the venturi injector 340. The hydrogen pressurization compensation is performed in the reducing gas buffer tank 600 by the pressurization pipe 650.

More specifically, the pressurization compensation may be to close the purge valve on the reducing gas buffer tank 600 every 1 to 3 hours, and boost the reducing gas buffer tank 600 with hydrogen to a pressure higher than the pressure of the reaction kettle 300, and the pressure difference between the two is not lower than 0.3MPa. The cross-flow filter is then backwashed by opening the bottom valve of the reducing gas surge tank 600.

Specifically, the method may specifically include:

at 1m ³ In the reaction kettle 300 of (2), the carrier gas is sent into the reaction kettle 300 for repeated replacement for 2-3 times until the oxygen content is qualified, acetone and 10% sodium hydroxide solution are respectively pumped into the reactant mixer 100, and isobutyraldehyde and hydrogen are simultaneously sent into the reaction kettle 300. The proportions of the reactants have been described in detail above and will not be described in detail here. Controlling the gas flow, increasing the pressure of the system to 0.3MPa, checking all valves on the circulation loop to ensure normal circulation, and then starting the circulation pump 700 to enable reactants to circularly react in the reaction kettle 300, the heat exchanger 200 and the solid-liquid separation unit 500.

In general, the device for preparing methyl isoamyl ketone provided by the utility model takes isobutyraldehyde and acetone as reactants, and continuously synthesizes methyl isoamyl ketone in one step through dehydration and hydrogenation under the action of a dehydration catalyst and a hydrogenation catalyst. Since the dehydration catalyst is not easily soluble in the first reactant and the second reactant, the reaction proceeds smoothly, requiring the addition of a large amount of water. In addition, the product obtained by the dehydration reaction is insoluble in water, so that water-oil two phases are gradually formed in the system, and even reactants are separated out, and strong stirring is required. The utility model utilizes the circulating pump 700 to form a circulating reaction loop among the reaction kettle 300, the heat exchanger 200 and the solid-liquid separation unit 500, effectively avoids the side reaction of the self condensation of reactants, and can achieve satisfactory conversion rate and selectivity at lower reaction temperature. The reaction mainly occurs in the nozzle 343 of the venturi eductor 340, and the conversion of the reaction and the selectivity of the product can be improved by controlling the residence time of the reaction zone of the nozzle 343. The yield of the product is improved through selective hydrogenation, the emission of three wastes is reduced, and the production cost is reduced. The method has the advantages of convenient continuous operation, high reaction yield, energy conservation and environmental protection, and is suitable for industrialization.

While the fundamental and principal features of the utility model and advantages of the utility model have been shown and described, it will be apparent to those skilled in the art that the utility model is not limited to the details of the foregoing exemplary embodiments, but may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Thus, the embodiments are to be regarded as illustrative in all respects, and not restrictive.

Furthermore, it should be understood that although the present disclosure describes embodiments, not every embodiment is provided with a separate embodiment, and that this description is provided for clarity only, and that the skilled artisan should recognize that the embodiments may be combined as appropriate to form other embodiments that will be understood by those skilled in the art.

Claims (10)

1. An apparatus for producing methyl isoamyl ketone comprising a reactant mixer, a heat exchanger, and a reaction vessel;

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.

2. The apparatus of claim 1, comprising a solid liquid separation unit comprising a mixture inlet, a clean liquid product outlet, and a slurry catalyst outlet, the mixture inlet being connected to the outlet of the heat exchanger, the slurry catalyst outlet being connected to the inlet of the venturi eductor.

3. The apparatus of claim 2, wherein the reaction vessel bottom is provided with a material outlet connected to an inlet of the heat exchanger, the apparatus further comprising a circulation pump to form a material circulation loop among the reaction vessel, the solid-liquid separation unit, and the heat exchanger.

4. A device according to claim 3, wherein the circulation pump satisfies at least one of the following conditions:

the circulating pump is arranged in a pipeline between the material outlet and the outlet of the heat exchanger;

the pump head of the circulating pump is configured such that the pressure difference between the inlet and the outlet of the circulating pump is not lower than 0.3MPa;

the circulation volume of the circulating pump is 20-50 times of the volume of the reaction kettle.

5. The apparatus of claim 2, wherein the solid-liquid separation unit is a cross-flow filter.

6. The apparatus of claim 2, wherein the apparatus comprises a reducing gas buffer tank;

the reducing gas buffer tank comprises 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 is connected to the slurry catalyst outlet;

the reducing gas buffer tank is connected with the reaction kettle through a balance pipe;

the reducing gas buffer tank further includes a pressurized pipe.

7. The apparatus of claim 1, wherein the length to diameter ratio of the reaction vessel is 2-8.

8. The apparatus of claim 1, wherein the venturi eductor comprises a material inlet, a nozzle, a mixing chamber, and a diffuser connected in sequence and having a plenum in communication with the mixing chamber, the material inlet being located at the top of the reaction vessel and the material inlet being connected to the outlet of the heat exchanger, the diffuser opening into the reaction vessel.

9. The apparatus of claim 8, wherein the venturi injector satisfies at least one of the following conditions:

an inlet section is arranged between the material inlet and the nozzle;

the inner diameter of the material inlet is not less than 10 times of the inner diameter of the nozzle;

the inner diameter of the mixing chamber is not smaller than the inner diameter of the nozzle and is not larger than 2 times of the inner diameter of the nozzle;

the length of the diffuser is not less than 30 times the length of the mixing chamber;

the included 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 apparatus of any one of claims 1-9, wherein the reactor is free of baffles and cooling coils;

and/or the reaction kettle is internally provided with no stirring motion part.