Device and method for preparing pseudo ionone

Abstract

The invention belongs to the technical field of fine chemical engineering, and particularly relates to a pseudo ionone preparation device and method.The preparation device comprises a circulation kettle, a pervaporation device, a first condenser, a second condenser, a water receiving tank and an outer circulation pipeline, and the pervaporation device is used for separating the organic steam vaporized from the circulating kettle into water vapor and anhydrous organic steam. When the preparation device is used for preparing the pseudo ionone, the water amount of a reaction system is strictly controlled, and the phenomenon that the ionization degree of a base catalyst in the reaction system is changed due to continuous accumulation of water in the reaction process along with the reaction is avoided, so that the reaction can be carried out in the most stable state, and the selectivity and the yield of the reaction are improved.

Description

Technical Field

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

[0002] Pseudoionone is usually prepared by aldol condensation reaction using citral and acetone as raw materials. However, the existing preparation methods generally have problems such as many self-condensation side reactions of citral, many self-condensation side reactions of acetone, and low yield. The reason is that as the reaction proceeds, water formed in the reaction process accumulates continuously, causing changes in the ionization degree of the base catalyst in the reaction system, so that the whole reaction cannot proceed under the optimal working conditions.

[0003] Chinese invention patent with publication number CN 107670678 B discloses a solid base catalyst, its preparation method and its method for preparing pseudoionone. The method includes: under the catalysis of the solid base catalyst, acetone reacts with citral to prepare pseudoionone; the solid base catalyst includes the following components: based on the weight of the catalyst, LiOH 15-40 wt%, MgCl 2 5-20 wt%, ZrO 2 55-65 wt%; the preparation method of the solid base catalyst includes the following steps: according to the proportion, adding ZrO 2 powder material into the aqueous solution of LiOH, stirring to obtain a suspension, evaporating the water to dryness, adding magnesium chloride, drying, and calcining to obtain the solid base catalyst. Example 5 gives the conversion rate of citral as 100%, the selectivity of pseudoionone as 97.8%, and the self-polymerization of citral accounts for about 1.0%. This invention has problems of complex catalyst preparation process and large amount of catalyst used.

[0004] Chinese patent application with publication number CN 112638855 A discloses a continuous synthesis method for pseudoionone. The method includes: (1) continuously introducing citral and acetone and an alkaline catalyst into a tubular reactor for aldol condensation reaction. The alkaline catalyst contains an inorganic base and an acetate. The tubular reactor sequentially includes a reaction section I, a reaction section II, and a reaction section III along the material flow direction. The reaction temperatures of the reaction section I, the reaction section II, and the reaction section III gradually increase 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. The acetone recovery device is a multi-kettle series device, and the temperature for recovering acetone from the condensation reaction product in each kettle gradually increases to obtain a de-acetone product; (3) subjecting the de-acetone product to extraction and stratification, and neutralizing the obtained oil layer with dilute acid to obtain pseudoionone. This synthesis method has problems of complex post-treatment process and low production efficiency.

[0005] In summary, the following problems generally exist in the prior art: 1. The selectivity of pseudoionone is low, the yield is low, and the utilization rate of acetone is low; 2. The post-treatment process is complex. SUMMARY OF THE INVENTION

[0006] Aiming at the deficiencies of the prior art, the present invention aims to provide a preparation device for pseudoionone with high selectivity of pseudoionone, high yield of pseudoionone, high utilization rate of acetone, and convenient post-treatment process.

[0007] To solve the above technical problems, the present invention first provides a preparation device for pseudoionone, comprising: A circulation kettle for containing a reaction raw material solution, the circulation kettle having a liquid phase outlet, a circulation kettle steam outlet, a condensate inlet, and a circulating liquid inlet; A pervaporation device for separating the organic vapor vaporized from the circulation kettle into water vapor and anhydrous organic vapor, the pervaporation device having a steam inlet, a steam outlet, and a water vapor outlet; the steam inlet is connected to the circulation kettle steam outlet through a pipeline; A first condenser for condensing the anhydrous organic vapor coming out of 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 for receiving the condensed water condensed by the second condenser, the water receiving tank further provided with an air extraction port; An external circulation pipeline connecting the circulating liquid inlet and the liquid phase outlet, and a catalyst for synthesizing pseudoionone is loaded on the external circulation pipeline.

[0008] The basic principle of the pseudoionone preparation device of the present invention to solve the problems existing in the prior art is to separate the water formed in the reaction from the reaction system through a pervaporation device in the aldol condensation reaction, so as to promote the progress of the reaction. Different from the reflux dehydration technology, the pervaporation dehydration technology has lower energy consumption and can solve the problem that acetone in the reflux liquid cannot separate water from the reflux liquid by the sedimentation principle. When the aldol condensation reaction temperature is carried out under the reflux temperature condition of the reaction system, the water formed in the reaction vaporizes under the action of the water-carrying agent and enters the pervaporation device. Since the water vapor molecules have a small molecular radius, they can pass through the micropores of the pervaporation membrane. The acetone or water-carrying agent in the reaction system is retained on the surface of the pervaporation membrane due to its large molecular radius. The water vapor passing through the pervaporation membrane is condensed by the second condenser and then enters the water receiving tank. The reaction system molecules retained on the surface of the pervaporation membrane enter the first condenser and are condensed and then returned to the circulation kettle to form a cycle. The water receiving tank is provided with an air extraction port, and the air extraction port is connected to the vacuum system to provide a pressure difference as the driving force for the pervaporation device. After separating water through the pervaporation device in the aldol condensation reaction, the composition of the reaction system is more single. Most importantly, the solubility of the catalyst in the reaction system will no longer change as when there is water. The solubility of the catalyst in the reaction system is constant, and the ionized hydroxide ions will be more stable, which is crucial for improving the selectivity of the reaction. Even if the same proportions of citral and acetone, the same reaction temperature, and the same catalyst feeding ratio are used in the aldol condensation reaction described in the present invention, different selectivity data will be obtained when lithium hydroxide or sodium hydroxide is used as the catalyst, which is caused by the different ionization degrees of the catalyst in the reaction system. The present invention indirectly controls the ionization degree of the catalyst by controlling the water in the reaction system at a low level. This lays a foundation for further improving the reaction selectivity and yield by using other technical means.

[0009] In addition, different from the prior art, the present invention reduces the amount of catalyst brought into the reaction system by loading the catalyst in the catalyst filling column of the external circulation. The advantages of such an operation are: 1. Avoiding the catalyst from being brought into the reaction system and triggering side reactions in series; 2. Reducing the difficulty of treating the catalyst in the reaction system after the reaction is completed; 3. Realizing the reuse of the catalyst.

[0010] To improve the convenience of switching the external circulation reaction device of the present invention, preferably, a circulation pump for transporting the materials in the circulation kettle into the first catalyst filling column or the second catalyst filling column is provided on the first circulation pipeline and / or the second circulation pipeline; cut-off valves for controlling the on-off of the pipeline are respectively provided on the first circulation pipeline and the second circulation pipeline. By setting the circulation pump, the reaction device can be changed from a plug flow reactor to a continuous stirred tank reactor similar to batch operation, which not only solves the problem of insufficient pressure for the reaction liquid to enter the catalyst filling column only by the static pressure of the liquid column, but also increases the control means for the reaction process. Setting the cut-off valve can facilitate the switching between the aldol condensation reactions catalyzed by the two catalysts.

[0011] Preferably, the first catalyst filling column has a first cavity for accommodating the first catalyst. The first catalyst filling 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; Wherein, the first liquid inlet is connected to the liquid phase outlet of the circulation kettle through the first circulation pipeline, the first liquid outlet is connected to the first liquid discharge pipe, and the first liquid discharge pipe is connected to the circulation liquid inlet of the circulation kettle.

[0012] Preferably, the second catalyst filling column has a second cavity for accommodating the second catalyst. The second catalyst filling 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; Wherein, the second liquid inlet is connected to the first circulation pipeline through the second circulation pipeline, and the second liquid outlet is connected to the first liquid discharge pipe through the second liquid discharge pipe.

[0013] To further improve the selectivity and yield of the reaction, the present invention provides two parallel catalyst filling columns, which can be filled with two catalysts to catalyze the aldol condensation reaction. The prior art basically uses a single catalyst, or uses multiple catalysts 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 feeding ratio of acetone. In this way, during the whole reaction process, except for the constant ratio of the catalyst, the concentrations of citral, acetone, and pseudoionone are constantly changing. The catalytic strength of the catalyst has a great influence on the selectivity of the reaction. By setting two catalysts and controlling the switching to another catalyst to catalyze the reaction at different reaction stages, the purpose of improving the reaction selectivity is achieved.

[0014] The internal structure of the catalyst filling column is crucial, which determines the loss rate of the catalyst and also determines the relative motion state of the liquid-solid two-phase. Preferably, a first support plate is provided in the first cavity. A cylindrical main body for accommodating the first catalyst is formed between the first support plate and the first liquid inlet. A filter medium is covered on the first support plate, 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 cylindrical main body for accommodating the second catalyst is formed between the second support plate and the second liquid inlet. A filter medium is covered on the second support plate, and the second liquid outlet is located below the second support plate. The catalyst filling column of the present invention has the simplest structure. When a quick-release joint is provided, the catalyst can be conveniently filled or replaced. 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.

[0015] Two catalyst filling columns are arranged in parallel, and their working states are crucial. Preferably, 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 is kept connected with the first liquid inlet of the first catalyst filling column, and the liquid phase outlet of the circulation kettle is kept disconnected from the second liquid inlet of the second catalyst filling column; in the second working state, the liquid phase outlet of the circulation kettle is kept connected with the second liquid inlet of the second catalyst filling column, and the liquid phase outlet of the circulation kettle is kept disconnected from the first liquid inlet of the first catalyst filling column. Through the cooperation of the pipeline and the cut-off valve, the switching work of the first catalyst filling column and the second catalyst filling column is realized. It can control the reaction to be catalyzed by the catalyst in the first catalyst filling column or the catalyst in the second catalyst filling column under different conversion rate conditions, so as to achieve the purpose of improving the selectivity and yield of the aldol condensation reaction.

[0016] The present invention also provides a method for preparing pseudoionone by using the above-mentioned preparation device, including: (1) Put a hydrocarbon solvent, citral and acetone into the circulation kettle to prepare a reaction raw material solution; (2) Under the action of a circulation pump, pass the reaction raw material solution into the external circulation pipeline for aldol condensation reaction to obtain pseudoionone; During the reaction process, the organic vapor vaporized from 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.

[0017] This preparation method is realized in the above-mentioned preparation device. First, the 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, the catalyst is reduced from being brought into the reaction system by the way of external circulation liquid-solid phase reaction, causing trouble in subsequent treatment; finally, the selectivity and yield of the reaction are improved by controlling the reaction to be catalyzed by different catalysts at different stages.

[0018] On the premise of adopting the above technical solution, the reaction can already 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. The hydrocarbon solvent has three functions: 1. As a water-carrying agent to reduce the proportion of water in the liquid phase of the circulating kettle; 2. To adjust the polarity of the reaction system, which is equivalent to adjusting the ionization degree of the catalyst; 3. To reduce the concentrations of citral and acetone and improve the selectivity. The feeding 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 at 0.1-0.3:1, relatively stable selectivity and yield indexes can be obtained.

[0019] On the basis of implementing the above technical solution, to further improve the utilization rate of acetone, preferably, the molar ratio of the acetone to the citral is 1.2-1.5:1. On the premise of ensuring that the selectivity and yield of pseudoionone do not decrease, adopting the method of reducing the input ratio of acetone to improve the utilization rate of acetone is a simple and effective method. The present invention controls the molar ratio of acetone to citral at 1.2-1.5:1, which not only ensures high selectivity and yield of pseudoionone but also reduces the side reaction of self-condensation of acetone, and reduces the losses and energy consumption in the process of recovering acetone, etc.

[0020] In the early stage of the Aldol condensation reaction, the concentrations of acetone and citral are high and the reaction rate is fast. A catalyst with weak alkalinity needs to be used to catalyze the reaction, so as to control the self-condensation of acetone and the self-condensation of citral at a relatively low level; in the later stage of the reaction, the concentration of citral is low and the concentration of acetone is low. A catalyst with strong alkalinity needs to be used to catalyze the reaction to ensure complete reaction without increasing the self-condensation reaction of acetone or the self-condensation reaction of citral. Preferably, the first catalyst is lithium hydroxide and the second catalyst is sodium hydroxide. Due to the implementation of the above technical solution, the reaction is transformed into a liquid-solid phase reaction. The filling amount of the catalyst does not have a particularly large influence on the reaction. Generally, good effects can be obtained when it is controlled at 2-10 wt% of the total amount of citral.

[0021] The reaction temperature is 60-100 °C. The reaction temperature is indirectly controlled by maintaining the vacuum degree of the water receiving tank at -0.09 - -0.02 MPa. This is because the resistance of the pervaporation device makes the vacuum degree of the water receiving tank inconsistent with the vacuum degree of the circulating kettle, indirectly controlling the vaporization temperature of the reaction system.

[0022] Through comparative research, preferably, on the basis of the implementation of the above technical solution, the preset conversion rate of citral is 75-85% to achieve the best reaction effect. That is, when the conversion rate of citral reaches 75-85%, replacing the catalyst from sodium hydroxide to lithium hydroxide can achieve the best effect. For convenient control, the flow rate of the circulation pump should be such that the materials in the circulation kettle can pass through the first catalyst filling column and / or the second catalyst filling column once in at most 0.5 hours, reducing the conversion rate of the reaction system at the inlet and outlet of the first catalyst filling column and / or the second catalyst filling column.

[0023] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) By means of a specific pervaporation device, the accumulation of moisture in the reaction system is avoided, the utilization rate of acetone is high, and the selectivity and yield of pseudoionone are high; (2) The post-treatment process is convenient and the amount of three wastes is small. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of the preparation device of pseudoionone of the present invention; Wherein: 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 - air extraction 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.

[0025] Wherein: AC - represents acetone; CHO - represents citral. DETAILED DESCRIPTION OF THE INVENTION

[0026] Figure 1 It is a schematic diagram of the preparation device of pseudoionone of the present invention. 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. Figure 1 The circulation kettle 1 has a liquid phase outlet 11, a circulation kettle steam outlet, a circulation liquid inlet 12 and various inlets for introducing acetone, citral and condensate.

[0027] ​

[0028] The pervaporation device 2 has a vapor inlet 21, a vapor outlet 22, and a water vapor outlet 23; the vapor inlet 21 is connected to the vapor outlet of the circulation kettle 1 through a pipeline, and is used to separate water from the organic vapor vaporized from the circulation kettle 1.

[0029] The first condenser 3 has a first condenser vapor inlet 31 and a condensate outlet 32, and the first condenser vapor inlet 31 is connected to the vapor 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 vapor coming out of the pervaporation device 2 into condensate.

[0030] The second condenser 4 has a water vapor inlet 41 and a second condenser condensed water outlet 42, and 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.

[0031] 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 condensed water outlet 42 of the second condenser through a pipeline, and is used to receive the condensed water condensed by the second condenser 4.

[0032] The external circulation pipeline includes a circulation pump 8, a first circulation pipeline 111, and a second circulation pipeline 112; A first catalyst filling column 6 is provided on the first circulation pipeline 111, and a second catalyst filling column 7 is provided on the second circulation pipeline 112; Cut-off valves for controlling the on-off of the pipeline are respectively provided on the first circulation pipeline 111 and the second circulation pipeline 112.

[0033] The first catalyst filling column 6 has a first cavity for accommodating the first catalyst. The first catalyst filling 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; Wherein, the first liquid inlet 61 is connected to the liquid phase outlet 11 of the circulation kettle 1 through the first circulation pipeline, the first liquid outlet 62 is connected to the first liquid outlet pipe 621, and the first liquid outlet pipe 621 is connected to the circulation kettle circulating liquid inlet 12.

[0034] The second catalyst filling column 7 has a second cavity for accommodating the second catalyst. The second catalyst filling column 7 includes a second liquid inlet 71 connected to the upper part of the second cavity and a second liquid outlet 72 connected to the lower part of the second cavity; the second liquid outlet 72 is connected to the second liquid outlet pipe 721; Wherein, 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.

[0035] A first support plate is provided in the first cavity. A cylindrical main body portion for accommodating the first catalyst is formed between the first support plate and the first liquid inlet 61. A filter medium is covered on the first support plate, 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. A cylindrical main body portion for accommodating the second catalyst is formed between the second support plate and the second liquid inlet 71. A filter medium is covered on the second support plate, and the second liquid outlet 72 is located below the second support plate.

[0036] 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 is kept in communication with the first liquid inlet 61 of the first catalyst filling column 6, and the liquid phase outlet 11 of the circulation kettle 1 is kept disconnected from the second liquid inlet 71 of the second catalyst filling column 7; in the second working state, the liquid phase outlet 11 of the circulation kettle 1 is kept in communication with the second liquid inlet 71 of the second catalyst filling column 7, and the liquid phase outlet 11 of the circulation kettle 1 is kept disconnected from the first liquid inlet 61 of the first catalyst filling column 6.

[0037] The present invention will be specifically described below through embodiments, but the present invention is not limited to these embodiments.

[0038] Gas chromatography detection conditions: Chromatographic column: SE-30 capillary chromatographic column; Detector: FID detector; Chromatographic column temperature: 160 °C; Injector temperature: 220 °C; Detector temperature: 220 °C.

[0039] Example 1 10.0 kg of lithium hydroxide was put into the first catalyst filling column, and 10.0 kg of sodium hydroxide was put into the second catalyst filling column.

[0040] Charge citral: 320 kg (content: 98.9 wt%), acetone: 160 kg (99.3 wt%), and cyclohexane: 80 kg into the circulation kettle. Open the valve at the air extraction port of the hot water receiving tank to evacuate the hot water receiving tank, and control the vacuum degree of the hot water receiving tank to be greater than -0.085 MPaG. Open the inlet valve of low-temperature water for the first condenser and the inlet valve of low-temperature water for the second condenser. Open the hot water valve for the jacket of the circulation kettle to heat the materials in the circulation kettle. When the temperature in the circulation kettle reaches 72 °C, set the reaction device to the first working state. Turn on the circulation pump, and after pumping out the materials in the circulation kettle through the circulation pump, boost and transport them into the first catalyst filling column. Set the flow rate of the circulation pump to 1200 kg / h and carry out the circulation reaction. The vaporized organic vapor enters the pervaporation device, and the water vapor in the organic vapor is separated by the pervaporation device, condensed by the second condenser, and then enters the hot water receiving tank. When the conversion rate of citral reaches 80% detected by gas chromatography, set the reaction device to the second working state and continue until the reaction is complete. When the citral content is less than 0.5% detected by gas chromatography, the reaction is complete, and transfer the reaction solution to the recovery kettle. Slowly add glacial acetic acid to the recovery kettle to adjust the pH value of the reaction solution to 7.5. Recover the mixed liquid of acetone and cyclohexane under normal pressure, and the residue is deweighted in a wiped film evaporator after filtration to obtain pseudoionone: 396.7 kg, content detected by gas chromatography: 98.1%, yield: 97.3%. Example 2

[0041] The process and process parameters of Example 2 are basically the same as those of Example 1, except that 150 kg of acetone is charged for the reaction. Finally, 392.9 kg of pseudoionone is obtained, with a content of 97.9% and a yield of 96.2%. Example 3

[0042] The process and process parameters of Example 3 are basically the same as those of Example 1, except that 180 kg of acetone is charged for the reaction. Finally, 401.1 kg of pseudoionone is obtained, with a content of 98.3% and a yield of 98.6%. Example 4

[0043] The process and process parameters of Example 4 are basically the same as those of Example 1, except that 32 kg of cyclohexane is charged for the reaction. Finally, 393.2 kg of pseudoionone is obtained, with a content of 98.0% and a yield of 96.4%. Example 5

[0044] The process and process parameters of Example 5 are basically the same as those of Example 1, except that 96 kg of cyclohexane is charged for the reaction. Finally, 397.6 kg of pseudoionone is obtained, with a content of 98.2% and a yield of 97.7%. Example 6

[0045] The process and process parameters of Example 6 are basically the same as those of Example 1, except that when the conversion rate of citral in the circulation kettle reaches 75%, the reaction device is adjusted from the first working state to the second working state for reaction. Finally, pseudoionone is obtained: 394.3 kg, content: 97.8%, yield: 96.5%. Example 7

[0046] The process and process parameters of Example 7 are basically the same as those of Example 1, except that when the conversion rate of citral in the circulation kettle reaches 85%, the reaction device is adjusted from the first working state to the second working state for reaction. Finally, pseudoionone is obtained: 396.8 kg, content: 97.9%, yield: 97.2%. Comparative Example 1

[0047] The process and process parameters of Comparative Example 1 are basically the same as those of Example 1, except that 10.0 kg of lithium hydroxide is directly added into the circulation kettle, and the vacuum valve of the water receiving tank is not opened for reaction. Finally, pseudoionone is obtained: 382.2 kg, content: 96.5%, yield: 92.3%. Comparative Example 2

[0048] The process and process parameters of Comparative Example 2 are basically the same as those of Example 1, except that 10.0 kg of lithium hydroxide is directly added into the circulation kettle for reaction. Finally, pseudoionone is obtained: 384.9 kg, content: 96.8%, yield: 93.2%. Comparative Example 3

[0049] The process and process parameters of Comparative Example 3 are basically the same as those of Example 1, except that the reaction is carried out in the first working state until the citral reacts completely. Finally, pseudoionone is obtained: 386.6 kg, content: 97.4%, yield: 94.2%. Comparative Example 4

[0050] The process and process parameters of Comparative Example 4 are basically the same as those of Example 1, except that when the conversion rate of citral reaches 65%, the reaction device is set to the second working state and the reaction is carried out until completion. Finally, pseudoionone is obtained: 392.6 kg, content: 96.5%, yield: 94.8%.

Claims

1. A device for preparing pseudoionone, characterized in that: include: A circulating kettle, used for containing the reaction raw material solution, the circulating kettle having 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 through a pipeline; A first condenser is used to condense the anhydrous organic steam from the steam outlet of the pervaporation device into a condensate, and return the condensate to the circulation kettle through the condensate inlet; A second condenser, used for condensing the water vapor coming out of the water vapor outlet of the pervaporation device into condensed water; A water receiving tank, used to receive condensed water condensed by the second condenser, and the water receiving tank is also provided with an air extraction port; 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.

2. The preparation device according to claim 1, characterized in that: 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 cut-off valves for controlling the on-off of the pipelines.

3. The preparation device according to claim 2, characterized in that: The first catalyst-filled column has a first cavity for accommodating a first catalyst, and the first catalyst-filled 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; The first liquid inlet is connected to the liquid phase outlet of the circulating kettle through a first circulating pipeline, the first liquid outlet is connected to a first liquid outlet pipe, and the first liquid outlet pipe is connected to a circulating liquid inlet of the circulating kettle.

4. The preparation device according to claim 3, characterized in that: The second catalyst-filled column has a second cavity for accommodating a second catalyst, and 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; Wherein, 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.

5. The preparation device according to claim 4, 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, a filter medium is covered on the first support plate, 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, a filter medium is covered on the second support plate, and the second liquid outlet is located below the second support plate.

6. A method for preparing pseudoionone using the preparation device according to any one of claims 1 to 5, 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.

7. The method according to claim 6, 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-filled column are kept in communication, and the liquid phase outlet of the circulation kettle and the second liquid inlet of the second catalyst-filled column are kept disconnected; in the second working state, the liquid phase outlet of the circulation kettle and the second liquid inlet of the second catalyst-filled column are kept in communication, and the liquid phase outlet of the circulation kettle and the first liquid inlet of the first catalyst-filled column are kept disconnected; The reaction is carried out in two stages. First, the entire device is allowed to react 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.

8. The method according to claim 6 or 7, 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.

9. The method according to claim 7, characterized in that: The first catalyst is lithium hydroxide, and the second catalyst is sodium hydroxide.

10. The method according to claim 7, characterized in that The preset conversion rate of the citral is 75-85%.

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