A preparation device and method for pseudoionone

Abstract

The present invention belongs to the field of fine chemical technology and specifically relates to a device and method for preparing pseudoionone. The device comprises a circulating kettle, a pervaporation device, a first condenser, a second condenser, a water receiving tank, and an external circulation pipeline. The pervaporation device is used to separate organic vapor vaporized from the circulating kettle into water vapor and anhydrous organic vapor. When using this device to prepare pseudoionone, the amount of water in the reaction system is strictly controlled, preventing the continuous accumulation of water during the reaction, which would cause changes in the ionization degree of the base catalyst in the reaction system. This allows the reaction to proceed in the most stable state, thereby improving the selectivity and yield of the reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemicals, and particularly relates to a device and method for preparing pseudoionone. Background Art

[0002] Pseudoionone is typically prepared using citral and acetone as raw materials via an aldol condensation reaction. However, existing preparation methods often suffer from numerous side reactions, including citral and acetone self-condensation, and low yields. This is due to the accumulation of water during the reaction, which changes the ionization degree of the base catalyst in the reaction system, preventing the entire reaction from proceeding under optimal conditions.

[0003] Chinese invention patent publication number CN 107670678 B discloses a solid base catalyst, a preparation method thereof, and a method for preparing pseudoionone using the solid base catalyst. The method comprises: reacting acetone with citral to produce pseudoionone under the catalysis of the solid base catalyst; the solid base catalyst comprises the following components: 15-40 wt% LiOH, 5-20 wt% MgCl2, and 55-65 wt% ZrO2, based on the weight of the catalyst; the preparation method comprises the following steps: adding ZrO2 powder to a LiOH aqueous solution in appropriate proportions, stirring to obtain a suspension, evaporating the water to dryness, adding magnesium chloride, drying, and calcining to obtain the solid base catalyst. Example 5 shows a citral conversion rate of 100%, a pseudoionone selectivity of 97.8%, and citral self-polymerization of approximately 1.0%. This invention suffers from the complex catalyst preparation process and the large amount of catalyst required.

[0004] The Chinese patent application with publication number CN 112638855 A discloses a continuous synthesis method of pseudoionone, which comprises: (1) continuously introducing citral and acetone and an alkaline catalyst into a tubular reactor for aldol condensation reaction, wherein the alkaline catalyst contains an inorganic base and acetate, and the tubular reactor comprises reaction section I, reaction section II and reaction section III in sequence along the logistics direction, wherein the reaction temperatures of reaction section I, reaction section II and reaction section III are gradually increased and are 0-10°C, 10-40°C and 75-90°C, respectively, to obtain a condensation reaction product; (2) continuously introducing the condensation reaction product into an acetone recovery device for acetone recovery, wherein the acetone recovery device is a multi-reactor series device, and the temperature of the condensation reaction product in each reactor is gradually increased to obtain a deacetonization product; (3) extracting and stratifying the deacetonization product, and neutralizing the obtained oil layer with dilute acid to obtain pseudoionone. This synthesis method has the problems of complex post-processing process and low production efficiency.

[0005] In summary, the existing technology generally has the following problems:

[0006] 1. Low selectivity of pseudoionone, low yield, and low acetone utilization;

[0007] 2. The post-processing process is complicated. Summary of the Invention

[0008] In view of the deficiencies of the prior art, the present invention aims to provide a device for preparing pseudoionone with high pseudoionone selectivity, high pseudoionone yield, high acetone utilization rate and convenient post-processing.

[0009] In order to solve the above technical problems, the present invention first provides a preparation device for pseudoionone, comprising:

[0010] A circulating kettle for containing the reaction raw material solution, wherein the circulating kettle has a liquid phase outlet, a circulating kettle steam outlet, a condensate inlet, and a circulating liquid inlet;

[0011] A pervaporation device is used to separate the organic steam vaporized from the circulating kettle into water vapor and anhydrous organic steam, the pervaporation device having a steam inlet, a steam outlet, and a water vapor outlet; the steam inlet is connected to the steam outlet of the circulating kettle via a pipeline;

[0012] a first condenser, which is used to condense the anhydrous organic vapor from the steam outlet of the pervaporation device into a condensate, and return the condensate to the circulation kettle through the condensate inlet;

[0013] a second condenser, for condensing the water vapor coming out of the water vapor outlet of the pervaporation device into condensed water;

[0014] A water receiving tank is used to receive the condensed water condensed by the second condenser, and the water receiving tank is also provided with an air extraction port;

[0015] An external circulation pipeline is connected to the circulating liquid inlet and the liquid phase outlet, and a catalyst for synthesizing pseudoionone is loaded on the external circulation pipeline.

[0016] The pseudoionone preparation apparatus described in the present invention addresses the problems of the prior art by separating the water formed during the aldol condensation reaction from the reaction system through a pervaporation device, thereby promoting the reaction. Unlike reflux dehydration technology, pervaporation dehydration technology consumes less energy and solves the problem of acetone in the reflux solution, which prevents water from being separated by sedimentation. When the aldol condensation reaction is carried out at the reflux temperature of the reaction system, the water formed by the reaction vaporizes under the action of a water-carrying agent and enters the pervaporation device. Due to the small molecular radius of water vapor molecules, they can pass through the micropores of the pervaporation membrane. Due to their large molecular radius, the acetone or water-carrying agent in the reaction system is trapped on the surface of the pervaporation membrane. The water vapor that permeates the pervaporation membrane is condensed in the second condenser and enters the water receiving tank. The reaction system molecules trapped on the pervaporation membrane surface enter the first condenser for condensation and return to the circulation kettle, thus completing the cycle. The water receiving tank is equipped with an air extraction port connected to a vacuum system, providing a pressure differential as power for the pervaporation device. Removing water from the aldol condensation reaction through the pervaporation device results in a more uniform composition of the reaction system. Most importantly, the solubility of the catalyst in the reaction system no longer fluctuates as it does when water is present. This constant catalyst solubility in the reaction system makes the ionized hydroxide ions more stable, which is crucial for improving the selectivity of the reaction. The aldol condensation reaction described herein yields significantly different selectivity data when using lithium hydroxide or sodium hydroxide as the catalyst, even when the same ratio of citral to acetone, reaction temperature, and catalyst charge ratio are used. This is due to the different degrees of ionization of the catalyst in the reaction system. By keeping the water content in the reaction system low, the present invention indirectly controls the catalyst's ionization. This lays the foundation for further improving the selectivity and yield of the reaction using other technical means.

[0017] Furthermore, unlike existing technologies, the present invention reduces the amount of catalyst introduced into the reaction system by loading the catalyst into an externally circulating catalyst-packed column. This approach offers the following advantages: 1. It prevents catalyst from entering the reaction system and triggering cascade side reactions; 2. It reduces the difficulty of handling the catalyst in the reaction system after the reaction is complete; and 3. It enables catalyst reuse.

[0018] To improve the convenience of switching the external circulation reaction device described in the present invention, preferably, the first circulation pipeline and / or the second circulation pipeline are provided with a circulation pump for transporting the material in the circulation kettle into the first catalyst-filled column or the second catalyst-filled column; the first circulation pipeline and the second circulation pipeline are respectively provided with a shut-off valve for controlling the on-off of the pipeline. By providing a circulation pump, the reaction device can be transformed from a plug flow reactor to a fully mixed flow reactor similar to batch operation, which not only solves the problem of insufficient pressure for the reaction liquid to enter the catalyst-filled column only through the static pressure of the liquid column, but also increases the control means of the reaction process. The provision of a shut-off valve can conveniently switch between the two catalysts catalyzing the aldol condensation reaction.

[0019] Preferably, the first catalyst-packed column has a first cavity for accommodating the first catalyst, and the first catalyst-packed column includes a first liquid inlet connected to the upper part of the first cavity and a first liquid outlet connected to the lower part of the first cavity;

[0020] The first liquid inlet is connected to the liquid phase outlet of the circulation kettle through a first circulation pipeline, the first liquid outlet is connected to a first liquid outlet pipe, and the first liquid outlet pipe is connected to the circulating liquid inlet of the circulation kettle.

[0021] Preferably, the second catalyst-packed column has a second cavity for accommodating the second catalyst, and the second catalyst-packed column includes a second liquid inlet connected to the upper part of the second cavity and a second liquid outlet connected to the lower part of the second cavity;

[0022] The second liquid inlet is connected to the first circulation pipeline through a second circulation pipeline, and the second liquid outlet is connected to the first liquid outlet pipe through a second liquid outlet pipe.

[0023] To further improve the selectivity and yield of the reaction, the present invention provides two parallel catalyst-packed columns that can be loaded with two catalysts to catalyze the aldol condensation reaction. Existing technologies generally use a single catalyst, or in other words, multiple catalysts are used simultaneously during the reaction. The present invention uses different catalysts at different stages of the reaction. To improve the utilization rate of acetone, the present invention reduces the acetone feed ratio. Thus, while the catalyst ratio remains constant throughout the reaction, the concentrations of citral, acetone, and pseudoionone all vary. The catalytic strength of the catalyst has a significant impact on the selectivity of the reaction. By providing two catalysts and controlling the switching of the catalyst to the other catalyst to catalyze the reaction at different reaction stages, the purpose of improving the reaction selectivity is achieved.

[0024] The internal structure of the catalyst-filled column is critical, determining the loss rate of the catalyst and also the relative motion state of the liquid and solid phases. Preferably, a first support plate is provided in the first cavity, and a columnar main body for accommodating the first catalyst is formed between the first support plate and the first liquid inlet, the first support plate is covered with a filter medium, and the first liquid outlet is located below the first support plate; and / or, a second support plate is provided in the second cavity, and a columnar main body for accommodating the second catalyst is formed between the second support plate and the second liquid inlet, the second support plate is covered with a filter medium, and the second liquid outlet is located below the second support plate. The catalyst-filled column described in the present invention has the simplest structure, and the catalyst can be conveniently filled or replaced after a quick-release joint is provided. The filter medium can be a filter bag or a sintered plate, and the sintered plate can be a ceramic sintered plate or a metal sintered plate.

[0025] The two catalyst-packed columns are arranged in parallel, and their operating states are critical. Preferably, the preparation apparatus has a first operating state and a second operating state. In the first operating state, the liquid-phase outlet of the circulating kettle is connected to the first liquid inlet of the first catalyst-packed column, while the liquid-phase outlet of the circulating kettle and the second liquid inlet of the second catalyst-packed column remain disconnected. In the second operating state, the liquid-phase outlet of the circulating kettle and the second liquid inlet of the second catalyst-packed column are connected, while the liquid-phase outlet of the circulating kettle and the first liquid inlet of the first catalyst-packed column remain disconnected. The switching operation of the first and second catalyst-packed columns is achieved by cooperating with the pipeline and the shut-off valve. This can control the reaction to use the catalyst in the first catalyst-packed column or the catalyst in the second catalyst-packed column under different conversion conditions, thereby achieving the purpose of improving the selectivity and yield of the aldol condensation reaction.

[0026] The present invention also provides a method for preparing pseudoionone using the preparation device, comprising:

[0027] (1) Adding hydrocarbon solvent, citral and acetone into a circulating kettle to prepare a reaction raw material solution;

[0028] (2) Under the action of a circulation pump, the reaction raw material solution is passed into an external circulation pipeline to carry out an aldol condensation reaction to obtain pseudoionone;

[0029] During the reaction process, the organic steam vaporized in the circulation kettle is separated from the water vapor by the pervaporation device and then returned to the circulation kettle, so that the water in the circulation kettle does not accumulate.

[0030] The preparation method is implemented in the preparation apparatus as described above. First, water formed in the reaction system is separated by technical means to avoid the adverse effects of water on the liquid-solid phase catalytic reaction; then, an external circulation liquid-solid phase reaction is used to reduce the catalyst from being brought into the reaction system, which would cause trouble in subsequent processing; finally, the reaction is controlled to use different catalysts at different stages to improve the selectivity and yield of the reaction.

[0031] Under the premise of adopting the above technical solution, the reaction can be controlled to proceed in the best direction. As a further supplement and improvement to the above technical solution, preferably, the mass ratio of the hydrocarbon solvent to the citral is 0.1-0.3:1, and the hydrocarbon solvent is selected from one of benzene, toluene, and cyclohexane. Hydrocarbon solvents have three functions: 1. As a water-carrying agent, it reduces the proportion of water in the liquid phase of the circulating kettle; 2. Adjusts the polarity of the reaction system, which is equivalent to adjusting the degree of ionization of the catalyst; 3. Reduces the concentration of citral and acetone and improves selectivity. The feed ratio of the solvent will affect the selectivity index of the reaction. When the mass ratio of the hydrocarbon solvent to the citral is controlled to be 0.1-0.3:1, relatively stable selectivity and yield indexes can be obtained.

[0032] Based on the implementation of the above technical solution, to further improve acetone utilization, the molar ratio of acetone to citral is preferably 1.2-1.5:1. While ensuring that the selectivity and yield of pseudoionones are not reduced, reducing the acetone input ratio to improve acetone utilization is a simple and effective method. The present invention controls the molar ratio of acetone to citral to 1.2-1.5:1, which not only ensures high selectivity and yield of pseudoionones, but also reduces the side reaction of acetone self-condensation, reducing losses and energy consumption in processes such as acetone recovery.

[0033] The concentration of acetone and citral in the early stage of Aldol condensation reaction is high, and reaction speed is fast. It is necessary to use a catalyst with weak alkalinity to catalyze the reaction, so that acetone self-condensation and citral self-condensation can be controlled to be at a lower level; Citral concentration is low in the later stage of reaction, and acetone concentration is low. It is necessary to use a catalyst with strong alkalinity to catalyze the reaction, so as to ensure that the reaction is complete and will not cause acetone self-condensation reaction or citral self-condensation reaction to increase. Preferably, the first catalyst is lithium hydroxide, and the second catalyst is sodium hydroxide. Due to the implementation of the above technical solutions, the reaction is converted into a liquid-solid phase reaction. The loading amount of the catalyst is not particularly large for the impact of the reaction, and generally the 2-10wt% of the citral total amount controlled to obtain relatively good results.

[0034] The reaction temperature is 60-100°C, and the reaction temperature is indirectly controlled by controlling the vacuum degree of the water tank to maintain at -0.09- -0.02MPa. This is because the resistance of the pervaporation device makes the vacuum degree of the water tank inconsistent with the vacuum degree of the circulating kettle, which indirectly controls the vaporization temperature of the reaction system.

[0035] The inventor, through comparative study, preferably, on the basis of the implementation of above-mentioned technical proposal, the preset conversion rate of described citral is 75-85% and can reach best reaction effect.When the conversion rate of citral reaches 75-85%, catalyst is replaced by lithium hydroxide by sodium hydroxide and can reach best effect.For ease of control, the flow of recycle pump should be able to meet and make the material in circulation kettle at most 0.5 hour can pass through the first catalyst-packed column and / or the second catalyst-packed column once, reduce the conversion rate of the first catalyst-packed column and / or the second catalyst-packed column import and export reaction system.

[0036] Compared with the prior art, the beneficial effects of the present invention are embodied in:

[0037] (1) The specific pervaporation device avoids the accumulation of water in the reaction system, resulting in high acetone utilization, high pseudoionone selectivity, and high yield;

[0038] (2) The post-treatment process is convenient and the amount of three wastes is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 Schematic diagram of the preparation apparatus of pseudoionone of the present invention;

[0040] Among them: Mark 1-circulation kettle; Mark 11-liquid phase outlet; Mark 111-first circulation pipeline; Mark 112-second circulation pipeline; Mark 12-circulation liquid inlet; Mark 2-pervaporation device; Mark 21-steam inlet; Mark 22-steam outlet; Mark 23-water vapor outlet; Mark 3-first condenser; Mark 31-first condenser steam inlet; Mark 32-condensate outlet; Mark 4-second condenser; Mark 41-water vapor inlet; Mark 42-second condenser condensate outlet; Mark 5-water receiving tank; Mark 51-condensate inlet; Mark 52-vacuum port; Mark 53-condensate outlet; Mark 6-first catalyst filling column; Mark 61-first liquid inlet; Mark 62-first liquid outlet; Mark 621-first liquid outlet pipe; Mark 7-second catalyst filling column; Mark 71-second liquid inlet; Mark 72-second liquid outlet; Mark 721-second liquid outlet pipe; Mark 8-circulation pump.

[0041] Among them: AC- represents acetone; CHO- represents citral. DETAILED DESCRIPTION

[0042] Figure 1is a schematic diagram of the preparation device of the pseudoionone of the present invention, comprising Figure 1 It can be seen that the preparation device mainly includes a circulation kettle 1, a pervaporation device 2, a first condenser 3, a second condenser 4, a water receiving tank 5 and an external circulation pipeline.

[0043] The circulating kettle 1 has a liquid phase outlet 11, a circulating kettle steam outlet, a circulating liquid inlet 12 and various inlets for introducing acetone, citral and condensate.

[0044] The pervaporation device 2 has a steam inlet 21 , a steam outlet 22 and a water vapor outlet 23 ; the steam inlet 21 is connected to the steam outlet of the circulation kettle 1 through a pipeline, and is used to separate water from the organic steam vaporized in the circulation kettle 1 .

[0045] The first condenser 3 has a first condenser steam inlet 31 and a condensate outlet 32. The first condenser steam inlet 31 is connected to the steam outlet 22 of the pervaporation device through a pipeline; the condensate outlet 32 is connected to the condensate inlet of the circulation kettle 1 through a pipeline, and is used to condense the anhydrous organic steam coming out of the pervaporation device 2 into condensate.

[0046] The second condenser 4 has a water vapor inlet 41 and a second condenser condensed water outlet 42 . The water vapor inlet 41 is connected to the water vapor outlet 23 of the pervaporation device through a pipeline, and is used to condense the water vapor coming out of the pervaporation device 2 into condensed water.

[0047] The water receiving tank 5 has a condensed water inlet 51 , a condensed water outlet 53 and an air extraction port 52 ; the condensed water inlet 51 is connected to the second condenser condensed water outlet 42 via a pipeline for receiving the condensed water condensed by the second condenser 4 .

[0048] The external circulation pipeline includes a circulation pump 8, a first circulation pipeline 111 and a second circulation pipeline 112;

[0049] The first circulation pipeline 111 is provided with a first catalyst-filled column 6, and the second circulation pipeline 112 is provided with a second catalyst-filled column 7;

[0050] The first circulation pipeline 111 and the second circulation pipeline 112 are respectively provided with a shut-off valve for controlling the on-off of the pipeline.

[0051] The first catalyst-filled column 6 has a first cavity for accommodating the first catalyst, and the first catalyst-filled column 6 includes a first liquid inlet 61 connected to the upper part of the first cavity and a first liquid outlet 62 connected to the lower part of the first cavity;

[0052] The first liquid inlet 61 is connected to the liquid phase outlet 11 of the circulation kettle 1 through a first circulation pipeline, the first liquid outlet 62 is connected to a first liquid outlet pipe 621 , and the first liquid outlet pipe 621 is connected to the circulating liquid inlet 12 of the circulation kettle.

[0053] The second catalyst-filled column 7 has a second cavity for accommodating the second catalyst. The second catalyst-filled column 7 includes a second liquid inlet 71 connected to the upper portion of the second cavity and a second liquid outlet 72 connected to the lower portion of the second cavity. The second liquid outlet 72 is connected to the second liquid outlet pipe 721.

[0054] The second liquid inlet 71 is connected to the first circulation pipeline through a second circulation pipeline, and the second liquid outlet 72 is connected to the first liquid outlet pipe 621 through a second liquid outlet pipe 721 .

[0055] A first support plate is provided in the first cavity, and a columnar main body for accommodating the first catalyst is formed between the first support plate and the first liquid inlet 61, the first support plate is covered with a filter medium, and the first liquid outlet 62 is located below the first support plate; and / or, a second support plate is provided in the second cavity, and a columnar main body for accommodating the second catalyst is formed between the second support plate and the second liquid inlet 71, the second support plate is covered with a filter medium, and the second liquid outlet 72 is located below the second support plate.

[0056] The preparation device has a first working state and a second working state. In the first working state, the liquid phase outlet 11 of the circulation kettle 1 and the first liquid inlet 61 of the first catalyst-filled column 6 remain connected, and the liquid phase outlet 11 of the circulation kettle 1 and the second liquid inlet 71 of the second catalyst-filled column 7 remain disconnected; in the second working state, the liquid phase outlet 11 of the circulation kettle 1 and the second liquid inlet 71 of the second catalyst-filled column 7 remain connected, and the liquid phase outlet 11 of the circulation kettle 1 and the first liquid inlet 61 of the first catalyst-filled column 6 remain disconnected.

[0057] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0058] Gas chromatography detection conditions: chromatographic column: SE-30 capillary column; detector: FID detector; chromatographic column temperature: 160°C; injector temperature: 220°C; detector temperature: 220°C.

[0059] Example 1

[0060] 10.0 kg of lithium hydroxide was added to the first catalyst-packed column, and 10.0 kg of sodium hydroxide was added to the second catalyst-packed column.

[0061] Add 320 kg of citral (98.9 wt%), 160 kg of acetone (99.3 wt%), and 80 kg of cyclohexane to the circulating kettle. Open the water receiving tank's exhaust valve to evacuate the water receiving tank, maintaining a vacuum level greater than -0.085 MPaG. Open the low-temperature water inlet valves for the first and second condensers. Open the hot water valve on the circulating kettle jacket to heat the contents. When the temperature in the circulating kettle reaches 72°C, set the reactor to the first operating mode. Start the circulating pump to pump the contents out of the circulating kettle and pressurize them into the first catalyst-packed column. Set the circulating pump flow rate to 1200 kg / h for the circulating reaction. The vaporized organic vapor enters the pervaporation unit, where water vapor is separated and condensed in the second condenser before entering the water receiving unit. When the citral conversion reaches 80% as determined by gas chromatography, set the reactor to the second operating mode and continue the reaction until complete. When the citral content was less than 0.5% as determined by gas chromatography, the reaction was complete, and the reaction solution was transferred to a recovery kettle. Glacial acetic acid was slowly added to the recovery kettle to adjust the pH of the reaction solution to 7.5. The acetone and cyclohexane mixture was recovered under normal pressure, and the residue was filtered and deweighed on a wiped-film evaporator to obtain 396.7 kg of pseudoionone, with a gas chromatography content of 98.1% and a yield of 97.3%. Example 2

[0062] The process and process parameters of Example 2 were basically the same as those of Example 1, except that 150 kg of acetone was added for the reaction. Finally, 392.9 kg of pseudoionone was obtained, with a content of 97.9% and a yield of 96.2%. Example 3

[0063] The process and process parameters of Example 3 were basically the same as those of Example 1, except that 180 kg of acetone was added for the reaction. Finally, 401.1 kg of pseudoionone was obtained, with a content of 98.3% and a yield of 98.6%. Example 4

[0064] The process and process parameters of Example 4 were basically the same as those of Example 1, except that 32 kg of cyclohexane was added for the reaction. Finally, 393.2 kg of pseudoionone was obtained, with a content of 98.0% and a yield of 96.4%. Example 5

[0065] The process and process parameters of Example 5 were basically the same as those of Example 1, except that 96 kg of cyclohexane was added for the reaction. Finally, 397.6 kg of pseudoionone was obtained with a content of 98.2% and a yield of 97.7%. Example 6

[0066] The process and process parameters of Example 6 were basically the same as those of Example 1, except that when the citral conversion rate in the circulating kettle reached 75%, the reaction apparatus was adjusted from the first operating state to the second operating state for reaction. Finally, 394.3 kg of pseudoionone was obtained, with a content of 97.8% and a yield of 96.5%. Example 7

[0067] The process and process parameters of Example 7 were basically the same as those of Example 1, except that when the citral conversion rate in the circulating kettle reached 85%, the reaction apparatus was adjusted from the first operating state to the second operating state for reaction. Finally, 396.8 kg of pseudoionone was obtained, with a content of 97.9% and a yield of 97.2%. Comparative Example 1

[0068] The process and parameters of Comparative Example 1 were essentially the same as those of Example 1, except that 10.0 kg of lithium hydroxide was added directly to the circulating kettle, and the reaction was conducted without opening the vacuum valve in the water receiving tank. The final product was 382.2 kg of pseudoionone, with a content of 96.5% and a yield of 92.3%. Comparative Example 2

[0069] The process and process parameters of Comparative Example 2 were basically the same as those of Example 1, except that 10.0 kg of lithium hydroxide was directly added to the circulating kettle for reaction. Finally, 384.9 kg of pseudoionone was obtained, with a content of 96.8% and a yield of 93.2%. Comparative Example 3

[0070] The process and process parameters of Comparative Example 3 were basically the same as those of Example 1, except that the reaction was carried out in the first working state until the reaction of citral was complete. Finally, 386.6 kg of pseudoionone was obtained, with a content of 97.4% and a yield of 94.2%. Comparative Example 4

[0071] The process and process parameters of Comparative Example 4 are basically the same as those of Example 1, except that when the citral conversion rate reaches 65%, the reaction apparatus is set to the second working state and continued until the reaction is complete. Finally, 392.6 kg of pseudoionone was obtained, with a content of 96.5% and a yield of 94.8%.

Claims

1. A device for preparing pseudoionone, characterized in that: include: A circulating kettle for containing the reaction raw material solution, wherein the circulating kettle has a liquid phase outlet, a circulating kettle steam outlet, a condensate inlet, and a circulating liquid inlet; A pervaporation device is used to separate the organic steam vaporized from the circulating kettle into water vapor and anhydrous organic steam, the pervaporation device having a steam inlet, a steam outlet, and a water vapor outlet; the steam inlet is connected to the steam outlet of the circulating kettle via a pipeline; a first condenser, for condensing the anhydrous organic vapor from the steam outlet of the pervaporation device into a condensate, and returning the condensate to the circulation kettle through the condensate inlet; a second condenser, for condensing the water vapor coming out of the water vapor outlet of the pervaporation device into condensed water; A water receiving tank is used to receive the condensed water condensed by the second condenser, and the water receiving tank is also provided with an air extraction port; an external circulation pipeline connecting the circulating liquid inlet and the liquid phase outlet, wherein the external circulation pipeline is loaded with a catalyst for synthesizing pseudoionone; The external circulation pipeline includes a circulation pump, a first circulation pipeline and a second circulation pipeline; The first circulation pipeline is provided with a first catalyst-filled column, and the second circulation pipeline is provided with a second catalyst-filled column; The first circulation pipeline and the second circulation pipeline are respectively provided with a shut-off valve for controlling the on-off of the pipeline; The first catalyst-filled column has a first cavity for accommodating a first catalyst; The second catalyst-filled column has a second cavity for accommodating a second catalyst.

2. The preparation device according to claim 1, characterized in that The first catalyst-filled column includes a first liquid inlet connected to the upper portion of the first cavity and a first liquid outlet connected to the lower portion of the first cavity; The first liquid inlet is connected to the liquid phase outlet of the circulation kettle through a first circulation pipeline, the first liquid outlet is connected to a first liquid outlet pipe, and the first liquid outlet pipe is connected to the circulating liquid inlet of the circulation kettle.

3. The preparation device according to claim 2, characterized in that The second catalyst-filled column includes a second liquid inlet connected to the upper portion of the second cavity and a second liquid outlet connected to the lower portion of the second cavity; The second liquid inlet is connected to the first circulation pipeline through a second circulation pipeline, and the second liquid outlet is connected to the first liquid outlet pipe through a second liquid outlet pipe.

4. The preparation device according to claim 3, characterized in that A first support plate is provided in the first cavity, a columnar main body for accommodating a first catalyst is formed between the first support plate and the first liquid inlet, the first support plate is covered with a filter medium, and the first liquid outlet is located below the first support plate; and / or a second support plate is provided in the second cavity, a columnar main body for accommodating a second catalyst is formed between the second support plate and the second liquid inlet, the second support plate is covered with a filter medium, and the second liquid outlet is located below the second support plate.

5. A method for preparing pseudoionone using the preparation device according to any one of claims 1 to 4, characterized in that: include: (1) Adding hydrocarbon solvent, citral and acetone into a circulating kettle to prepare a reaction raw material solution; (2) Under the action of a circulation pump, the reaction raw material solution is passed into an external circulation pipeline to carry out an aldol condensation reaction to obtain pseudoionone; During the reaction process, the organic steam vaporized in the circulation kettle is separated from the water vapor by the pervaporation device and then returned to the circulation kettle, so that the water in the circulation kettle does not accumulate.

6. The method according to claim 5, characterized in that The preparation device has a first working state and a second working state. In the first working state, the liquid phase outlet of the circulation kettle and the first liquid inlet of the first catalyst-packed column remain connected, and the liquid phase outlet of the circulation kettle and the second liquid inlet of the second catalyst-packed column remain disconnected; in the second working state, the liquid phase outlet of the circulation kettle and the second liquid inlet of the second catalyst-packed column remain connected, and the liquid phase outlet of the circulation kettle and the first liquid inlet of the first catalyst-packed column remain disconnected; The reaction is carried out in two stages. First, the entire device is reacted in a first working state. When the citral in the circulation kettle reaches a preset conversion rate, it is switched to a second working state until the reaction is complete.

7. The method according to claim 5 or 6, characterized in that The mass ratio of the hydrocarbon solvent to the citral is 0.1-0.3:1, and the hydrocarbon solvent is selected from one of benzene, toluene, and cyclohexane; The molar ratio of the acetone to the citral is 1.2-1.5:

1.

8. The method according to claim 6, characterized in that The first catalyst is lithium hydroxide, and the second catalyst is sodium hydroxide.

9. The method according to claim 6, characterized in that The preset conversion rate of the citral is 75-85%.

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