Rectification system for the preparation of divinylbenzene

Abstract

The present application belongs to the technical field of divinylbenzene preparation, and particularly relates to a rectification system for preparing divinylbenzene; comprising a rectification tower, the rectification tower is a structured packing tower, the metal structured packing in the structured packing tower body is subjected to dilute acid liquid soaking treatment and is filled in the structured packing tower to perform rectification operation. After the structured packing is soaked with dilute acid liquid, the cleaned structured packing is refilled in the structured packing tower, under the condition that the tower height, reflux ratio, tower vacuum degree and polymerization inhibitor content are unchanged, the rectification efficiency of the structured packing tower can be significantly improved by the structured packing subjected to dilute acid liquid soaking treatment, the concentration of divinylbenzene collected from the top of the tower is significantly increased, and the concentration of divinylbenzene polymer in divinylbenzene is significantly decreased, which indicates that the purity of divinylbenzene produced by the process is significantly improved compared with the purity of divinylbenzene produced by the previous process, and the economic benefit is better.

Description

Technical Field

[0001] This invention belongs to the field of divinylbenzene preparation technology, specifically relating to a distillation system for preparing divinylbenzene. Background Technology

[0002] Divinylbenzene, also known as 1,2-divinylbenzene, is a colorless liquid mainly prepared by high-temperature dehydrogenation of diethylbenzene. The products are predominantly meta-isomers with ethylvinylbenzene as a byproduct. As an important chemical raw material, it is mainly used in the synthesis of ion exchange resins, ABS resins, and optical materials. The content of the para-isomer directly affects the resin properties.

[0003] In the preparation of divinylbenzene, after pretreatment and vaporization of the raw materials, a catalytic dehydrogenation reaction is carried out. The reaction product is then purified by distillation to obtain the final product, divinylbenzene. The distillation equipment primarily used is a structured packed column. However, divinylbenzene readily self-polymerizes, forming divinylbenzene polymers. In existing processes, the polymer content in divinylbenzene exceeds 50 mg / L, which does not meet downstream application requirements. Summary of the Invention

[0004] Based on this, this application provides a distillation system for preparing divinylbenzene to solve the technical problem of excessively high polymer content in divinylbenzene in the prior art.

[0005] The technical solution to the above-mentioned technical problems in this application is as follows: A distillation system for preparing divinylbenzene includes a distillation column, the distillation column comprising a column body and structured metal packing, the structured metal packing being treated by immersion in dilute acid.

[0006] Preferably, the dilute acid soaking treatment includes the following steps: S1 involves immersing the structured metal filler in a dilute acid solution; S2 is soaked at low temperature for 0.5 to 10 hours; S3 water wash.

[0007] Preferably, the dilute acid solution is one of hydrochloric acid (0.1wt%–5wt%), sulfuric acid (0.1wt%–5wt%), or nitric acid (0.1wt%–5wt%).

[0008] Preferably, the structured metal packing is perforated corrugated packing with a mesh size of 55-60 mesh.

[0009] Compared with the prior art, this application has at least the following advantages: This application provides a distillation system for preparing divinylbenzene. After soaking the structured metal packing with dilute acid, the soaked structured metal packing is then repacked into a structured packed column (distillation column). Under the condition that the column height, reflux ratio, vacuum degree and polymerization inhibitor content remain unchanged, the structured metal packing treated with dilute acid can significantly reduce the polymer content in divinylbenzene. The polymer concentration in divinylbenzene is reduced from more than 50 mg / L to less than 20 mg / L, which greatly reduces the downstream processing cost. Attached Figure Description

[0010] Figure 1 This is a photo of the site where the structured metal packing was immersed in acid.

[0011] Figure 2 This is a schematic diagram showing the process of immersing a structured metal filler in acid, washing it with water, drying it, and allowing it to stand. Detailed Implementation

[0012] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0013] It should be noted that when an element is referred to as being "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "left," "right," "top," "bottom," "end," "top," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

[0014] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0015] In order to reduce the polymer content in divinylbenzene, this application proposes a distillation system for preparing divinylbenzene, including a distillation column, the distillation column including a column body and a structured metal packing, the structured metal packing being treated by soaking in dilute acid.

[0016] After preparing crude divinylbenzene, a distillation purification process is required. The distillation column is a crucial step in this process, and structured packed columns are primarily used. These columns are chosen because they offer advantages such as extremely low pressure drop, extremely high separation efficiency, low liquid holdup, and short residence time, making them suitable for the distillation purification of divinylbenzene. After distillation using a structured packed column, divinylbenzene of different concentrations will be collected, such as 55% by mass, 63% by mass, and 80% by mass. However, divinylbenzene undergoes self-polymerization, forming polymers. Higher purity divinylbenzene is more prone to polymerization, eventually forming divinylbenzene polymers. These polymers are colloidal and, over time, can clog the structured packing in a packed tower, causing a "blockage" phenomenon. Typically, the structured packing is metal-based, using either perforated plate corrugated packing or wire mesh corrugated packing. If perforated plate corrugated packing is used, the divinylbenzene polymer will clog the perforated plate. Therefore, it is necessary to periodically remove the metal-based structured packing from the packed tower and clean out the divinylbenzene polymer within it. Generally, cleaning the metal-based packing involves... When structured packing is treated with water rinsing, or when heavy cleaning of metal structured packing is required, it is soaked in a dilute alkaline solution (1wt%–5wt% sodium hydroxide solution) and then cleaned. Regardless of whether water rinsing or dilute alkaline soaking is used, when the cleaned metal structured packing is repacked in a structured packing column for distillation, the concentration of divinylbenzene polymer after distillation is close to the original concentration of divinylbenzene polymer. However, if workers unintentionally soak and clean the metal structured packing with dilute acid and then repack the metal structured packing with dilute acid into the structured packing column, the results will be different. During distillation operations, tests revealed a significant decrease in the polymer concentration of divinylbenzene discharged from the top of the column, regardless of the concentration of divinylbenzene collected from the top. Subsequent repeated experiments showed that soaking the structured metal packing in dilute hydrochloric acid, dilute sulfuric acid, or dilute nitric acid significantly reduced the polymer concentration of divinylbenzene collected from the top of the column compared to cleaning with water or dilute alkali. This indicates that soaking the structured metal packing in dilute acid can improve the distillation efficiency of the structured packed column.

[0017] Furthermore, the dilute acid soaking treatment includes the following steps: Prepare a dilute acid solution by adding it to a container and letting it stand to form an initial acid leaching solution. Specifically, select a corrosion-resistant storage tank (such as a polyethylene tank), add a certain amount of clean water to the tank, and add one of hydrochloric acid, sulfuric acid, or nitric acid of a preset concentration to prepare a diluted acid solution. Stir and let it stand for 1-3 hours.

[0018] Take the structured metal packing and immerse it in the initial acid leaching solution. It should be noted that the structured metal packing can be brand new, unused, or it can be metal packing that has been used in a structured packed tower. Used metal packing may contain divinylbenzene, divinylbenzene polymers, divinylbenzene derivatives or isomers, polymerization inhibitors, and unreacted divinylbenzene, etc. Generally, the entire structured metal packing is immersed in the initial acid leaching solution.

[0019] Under low-temperature conditions, the structured metal packing is acid-leached for 0.5–10 hours, followed by cleaning. The low-temperature range is 0–5°C. For unused structured metal packing, since there are no blockages inside, only soaking is used. For used structured metal packing, during the dilute acid soaking process, stirring, shaking, or ultrasonic vibration are used to clean the packing. The above-mentioned stirring, shaking, or ultrasonic vibration cleaning methods are existing technologies and will not be elaborated here.

[0020] The acid-leached structured metal packing is removed, forming a primary acid-leached structured metal packing. This primary acid-leached metal packing is then washed with water to remove residual dilute acid solution. After standing, the water inside the metal packing evaporates, and the primary acid-leached metal packing is then loaded into the structured packing tower. For unused metal packing, since there are no blockages inside, the acid leaching solution after washing is relatively clear and can be reused. For used metal packing, the cleaning process removes the blockage material that was trapped inside the packing, which either settles at the bottom of the dilute acid solution or dissolves in it.

[0021] The initial acid leaching solution after soaking becomes a primary acid leaching solution and is stored. The stored primary acid leaching solution is a relatively clear acid leaching solution or an acid leaching solution containing a small amount or some blockage, and is not heavily contaminated. The acid leaching solution after soaking is sealed and stored at a temperature of 0 to 5°C.

[0022] Furthermore, the dilute acid solution (expressed as a mass fraction, wt%) is one of the following: 0.1wt%–5wt% hydrochloric acid, 0.1wt%–5wt% sulfuric acid, or 0.1wt%–5wt% nitric acid. A low-concentration dilute acid solution is chosen. If the concentration is too high, the acid will react violently with the structured metal packing, damaging its internal structure and causing harm. However, using a 0.1wt%–5wt% dilute acid solution and immersing the structured metal packing in it for 0.5–10 hours, structural strength tests show that the internal structure of the structured metal packing is not significantly damaged.

[0023] Preferably, the dilute acid solution is sulfuric acid with a concentration of 0.1 wt% to 5 wt%. Since dilute hydrochloric acid solution and dilute nitric acid solution are volatile, they are not suitable for long-term storage. However, the dilute acid solution after use is relatively clear, and the dilute sulfuric acid solution still contains acid radical ions, so the dilute sulfuric acid solution can be stored and reused.

[0024] Specifically, the dilute acid solution is one of the following: 0.5 wt% hydrochloric acid, 0.5 wt% sulfuric acid, or 0.5 wt% nitric acid. This concentration of the dilute acid solution is relatively low; therefore, the immersion time of the acid metal in the structured filler is relatively long.

[0025] Specifically, the dilute acid solution is one of the following: 1 wt% hydrochloric acid, 1 wt% sulfuric acid, or 1 wt% nitric acid. This concentration of dilute acid solution is relatively low; therefore, the acid leaching time for the structured metal filler is relatively long.

[0026] Specifically, the dilute acid solution is one of the following: 2 wt% hydrochloric acid, 2 wt% sulfuric acid, or 2 wt% nitric acid. This concentration of dilute acid solution is relatively moderate, therefore, the acid leaching time for the structured metal filler is moderate.

[0027] Specifically, the dilute acid solution is one of the following: 3 wt% hydrochloric acid, 3 wt% sulfuric acid, or 3 wt% nitric acid. This concentration of dilute acid solution is relatively moderate, therefore, the acid leaching time for the structured metal filler is moderate.

[0028] Specifically, the dilute acid solution is one of the following: 4 wt% hydrochloric acid, 4 wt% sulfuric acid, or 4 wt% nitric acid. This concentration of dilute acid solution is relatively high, therefore, the acid leaching time for the structured metal filler is relatively short.

[0029] Specifically, the dilute acid solution is one of the following: 5 wt% hydrochloric acid, 5 wt% sulfuric acid, or 5 wt% nitric acid. This concentration of dilute acid solution is relatively high, therefore, the acid leaching time for the structured metal filler is relatively short.

[0030] Furthermore, during the acid leaching process of structured metal packing, some of the blockages inside the structured metal packing are not easily removed during the cleaning process. Therefore, it is necessary to periodically turn and rotate the structured metal packing to facilitate the removal of blockages.

[0031] Preferably, it should be noted that if the primary acid leaching solution is a dilute acid solution of 1wt% to 5wt%, it would be a significant waste of acid if the primary acid leaching solution were not reused. Therefore, it can be reused to clean the metal structured filler again. The dilute acid leaching treatment also includes the following steps: Furthermore, the distillation system also includes a crude fractionation column and a light-light product removal column. The feed inlet of the crude fractionation column is used to introduce crude divinylbenzene product. The feed inlet of the light-light product removal column is connected to the bottom outlet of the crude fractionation column. The feed inlet of the distillation column is connected to the bottom outlet of the light-light product removal column.

[0032] Specifically, the coarse separation tower is a sieve plate tower. After the crude divinylbenzene product is introduced into the feed port of the coarse separation tower, all light components (benzene, toluene, ethylbenzene, etc.) and most of the divinylbenzene are mainly distilled off at the top of the tower, while heavy components, including the target product divinylbenzene, high-boiling-point tar, polymers, and some polymerization inhibitors, are discharged from the bottom of the tower.

[0033] Specifically, the light component removal tower is a plate tower. The feed inlet of the light component removal tower is fed into the heavy component in the bottom of the coarse fractionation tower. All light components (benzene, toluene, ethylbenzene) and diethylbenzene are distilled off at the top of the tower, while the heavy component, including a large amount of the target product divinylbenzene and a small amount of high-boiling-point tar, polymer, and some polymerization inhibitors, is discharged from the bottom of the tower.

[0034] Specifically, the distillation column is a structured packed column. The feed inlet of the structured packed column is fed with the heavy components from the bottom of the light component removal column. Divinylbenzene product is collected from the top of the column, such as divinylbenzene with a mass concentration of 55%, divinylbenzene with a mass concentration of 63%, or divinylbenzene with a mass concentration of 80%. Heavy components are discharged from the bottom of the column, including divinylbenzene polymers, divinylbenzene derivatives or isomers, polymerization inhibitors, and unreacted divinylbenzene.

[0035] Furthermore, the structured metal packing is selected from perforated plate corrugated packing, with a mesh size of 55-60 mesh. This avoids the possibility of the divinylbenzene polymer clogging the pores of the perforated plate corrugated packing if the mesh size is too small.

[0036] The following embodiments are made in accordance with this application, and in conjunction with Figure 1 and Figure 2 To provide further explanation.

[0037] Comparative Example 1: Divinylbenzene with a mass concentration of 55% extracted from the top of the tower. 1. Basic information about structured packed towers The tower is 19 meters high and 1.6 meters in diameter. The structured metal packing is perforated corrugated packing with a mesh size of 60 mesh. The structured metal packing consists of 4 sections of 3 meters each with a radius of 1.4 meters. There is a space of about 1 meter between the sections for installing a redistributor. The reflux ratio (the ratio of the reflux flow rate at the top of the tower to the product output flow rate) is 8:1, and the pressure drop per meter of packing is 3 mbar.

[0038] 2. Feeding and discharging information The heavy components (containing a large amount of the target product divinylbenzene and other components) in the bottom of the light component removal tower are fed into the feed inlet of the structured packed tower. After distillation in the structured packed tower, the target product divinylbenzene is taken out from the top of the tower, and the remaining heavy components are taken out from the bottom of the tower.

[0039] 3. Rinse the structured metal packing with clean water. The structured metal packing consists of 4 sections × 3 meters per section (the structured metal packing is brand new and unused, and needs to be installed in the structured packing tower for the first time). The structured metal packing is rinsed with clean water at 5°C for 2 hours to remove impurities remaining on the surface of the structured metal packing. The cleaned structured metal packing is then completely filled into the structured packing tower.

[0040] 4. The concentration of divinylbenzene polymer in a 55% (w / w) divinylbenzene solution was detected. The polymer content in divinylbenzene products was determined using a spectrophotometer. The spectrophotometric method was as follows: 1. Determine the maximum absorption wavelength: Take a small amount of divinylbenzene solution containing polymer and scan the entire wavelength range of 200–800 nm using a UV-Vis spectrophotometer. 2. Prepare a standard solution: Accurately weigh high-purity polymer and dissolve it in divinylbenzene solvent to prepare a standard solution. 3. Prepare a blank solution: Use pure divinylbenzene without polymer as a blank control. 4. Instrument calibration and blank correction: Place the blank solution in the optical path and adjust the transmittance to T=100% (A=0.000) to complete baseline correction. 5. Measure the absorbance of the standard solutions: Measure the absorbance of each standard solution at the same wavelength sequentially. 6. Plot a standard curve: Plot a scatter plot with concentration on the x-axis and absorbance on the y-axis and perform linear regression. 7. Measure the absorbance of unknown samples and calculate their concentration: Take the divinylbenzene sample to be tested and measure its absorbance under the same conditions.

[0041] Divinylbenzene (55% mass concentration) collected from the top of the distillation column was sampled, and three sets of samples were taken (the three sets of samples were extracted at 15-minute intervals during the divinylbenzene collection process from the top of the column). The polymer concentration in the divinylbenzene of the three sets of samples was calculated by spectrophotometry. The concentrations of the three sets of samples (rounded down) were 35 mg / L, 34 mg / L and 35 mg / L, respectively, and the average polymer concentration in divinylbenzene was 34.7 mg / L.

[0042] Experimental Example 1: Extraction of divinylbenzene with a mass concentration of 55% 1. The basic information of the structured packed tower is the same as that of Comparative Example 1.

[0043] 2. The feeding and discharging information is the same as that of Comparative Example 1.

[0044] 3. The structured metal filler is treated by immersion in a 3wt% dilute acid solution: see [link / reference] Figure 1 and Figure 2 The structured metal packing consists of 4 sections × 3 meters per section (the structured metal packing is brand new and unused, and needs to be installed in the structured packing tower for the first time). The structured metal packing is treated by soaking in a 3wt% dilute sulfuric acid solution. The structured metal packing is immersed in the dilute sulfuric acid solution at 5°C for 2 hours. After soaking, the structured metal packing is removed, forming a first-time acid-soaked structured metal packing. The structured metal packing is then rinsed with clean water, allowed to stand and dry, and then all the first-time acid-soaked structured metal packing is loaded into the structured packing tower.

[0045] 4. The concentration of divinylbenzene polymer in a 55% (w / w) divinylbenzene solution was detected. The polymer content in the divinylbenzene product was determined by spectrophotometry, and the detection method was the same as that in Comparative Example 1.

[0046] Divinylbenzene (55% mass concentration) collected from the top of the distillation column was sampled, and three sets of samples were taken (the three sets of samples were extracted at 15-minute intervals during the divinylbenzene collection process from the top of the column). The polymer concentration in the divinylbenzene of the three sets of samples was calculated by spectrophotometry. The concentrations of the three sets of samples (rounded down) were 12 mg / L, 10 mg / L and 13 mg / L, respectively, and the average polymer concentration in divinylbenzene was 11.7 mg / L.

[0047] Comparative Example 2: Divinylbenzene with a mass concentration of 63% extracted from the top of the tower. 1. The basic information of the structured packed tower is the same as that of Comparative Example 1.

[0048] 2. The feeding and discharging information is the same as that of Comparative Example 1.

[0049] 3. The structured metal packing is treated by rinsing with clean water. The structured metal packing consists of 4 sections × 3 meters per section (the structured metal packing is brand new and unused, and needs to be installed in the structured packing tower for the first time). The structured metal packing is rinsed with clean water at 5°C for 2 hours to remove impurities remaining on the surface of the structured packing. The cleaned structured metal packing is then completely filled into the structured packing tower.

[0050] 4. The concentration of divinylbenzene polymer in divinylbenzene with a mass concentration of 63% was detected. The polymer content in the divinylbenzene product was determined by spectrophotometry, and the detection method was the same as that in Comparative Example 1.

[0051] Divinylbenzene collected from the top of the distillation column was sampled, and three sets of samples were taken (the three sets of samples were extracted at 15-minute intervals during the divinylbenzene collection process). The polymer concentration in the divinylbenzene of the three sets of samples was calculated by spectrophotometry. The concentrations of the three sets of samples (rounded down) were 42 mg / L, 43 mg / L and 42 mg / L, respectively, and the average polymer concentration in divinylbenzene was 42.3 mg / L.

[0052] Experimental Example 2: Divinylbenzene with a mass concentration of 63% was extracted from the top of the tower. 1. The basic information of the structured packed tower is the same as that of Comparative Example 1.

[0053] 2. The feeding and discharging information is the same as that of Comparative Example 1.

[0054] 3. The structured metal filler was treated by soaking in 3wt% dilute acid solution, which is the same as the dilute acid solution soaking treatment in Experiment Example 1.

[0055] 4. The concentration of divinylbenzene polymer in divinylbenzene with a mass concentration of 63% was detected. The polymer content in the divinylbenzene product was determined by spectrophotometry, and the detection method was the same as that in Comparative Example 1.

[0056] Divinylbenzene collected from the top of the distillation column was sampled, and three sets of samples were taken (the three sets of samples were extracted at 15-minute intervals during the divinylbenzene collection process). The polymer concentration in the divinylbenzene of the three sets of samples was calculated by spectrophotometry. The concentrations of the three sets of samples (rounded down) were 14 mg / L, 14 mg / L and 13 mg / L, respectively, and the average polymer concentration in divinylbenzene was 13.6 mg / L.

[0057] Comparative Example 3: Divinylbenzene with a mass concentration of 80% extracted from the top of the tower. 1. The basic information of the structured packed tower is the same as that of Comparative Example 1.

[0058] 2. The feeding and discharging information is the same as that of Comparative Example 1.

[0059] 3. The structured metal packing is treated by rinsing with clean water. The structured metal packing consists of 4 sections × 3 meters per section (the structured metal packing is brand new and unused, and needs to be installed in the structured packing tower for the first time). The structured packing is rinsed with clean water at 5°C for 2 hours to remove impurities remaining on the surface of the structured packing. The cleaned structured packing is then completely filled into the structured packing tower.

[0060] 4. The concentration of divinylbenzene polymer in divinylbenzene with a mass concentration of 80% was detected. The polymer content in the divinylbenzene product was determined by spectrophotometry, and the detection method was the same as that in Comparative Example 1.

[0061] Divinylbenzene collected from the top of the distillation column was sampled, and three sets of samples were taken (the three sets of samples were extracted at 15-minute intervals during the divinylbenzene collection process). The polymer concentration in the divinylbenzene of the three sets of samples was calculated by spectrophotometry. The concentrations of the three sets of samples (rounded down) were 56 mg / L, 55 mg / L and 54 mg / L, respectively, and the average polymer concentration in divinylbenzene was 55 mg / L.

[0062] Experimental Example 3: Divinylbenzene with a mass concentration of 80% was extracted from the top of the tower. 1. The basic information of the structured packed tower is the same as that of Comparative Example 1.

[0063] 2. The feeding and discharging information is the same as that of Comparative Example 1.

[0064] 3. The structured metal filler was treated by soaking in 3wt% dilute acid solution, which is the same as the dilute acid solution soaking treatment in Experiment Example 1.

[0065] 4. The concentration of divinylbenzene polymer in divinylbenzene with a mass concentration of 80% was detected. The polymer content in the divinylbenzene product was determined by spectrophotometry, and the detection method was the same as that in Comparative Example 1.

[0066] Divinylbenzene collected from the top of the distillation column was sampled, and three sets of samples were taken (the three sets of samples were extracted at 15-minute intervals during the divinylbenzene collection process). The polymer concentration in the divinylbenzene of the three sets of samples was calculated by spectrophotometry. The concentrations of the three sets of samples (rounded down) were 18 mg / L, 18 mg / L and 19 mg / L, respectively, and the average polymer concentration in divinylbenzene was 18.3 mg / L.

[0067] Based on the above comparative examples and embodiments, the following table is prepared. Table of polymer concentrations in divinylbenzene determined by spectrophotometry ; As shown in the table above and the examples, compared with the metal structured packing after rinsing with clean water, the polymer concentration in divinylbenzene after soaking with 3wt% disulfide is significantly reduced, regardless of whether the divinylbenzene has a mass concentration of 55%, 63%, or 80% as of the top of the tower. In particular, the polymer concentration in the 80% divinylbenzene is reduced from more than 50 mg / L to less than 20 mg / L, which greatly reduces the downstream processing cost.

[0068] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A distillation system for preparing divinylbenzene, comprising a distillation column, said distillation column including a column body and structured metal packing, characterized in that, The structured metal filler was treated by soaking in dilute acid.

2. The distillation system for preparing divinylbenzene as described in claim 1, characterized in that, The dilute acid soaking treatment includes the following steps: S1 involves immersing the structured metal filler in a dilute acid solution; S2 is soaked at low temperature for 0.5 to 10 hours; S3 water wash.

3. The distillation system for preparing divinylbenzene as described in claim 2, characterized in that, The dilute acid solution is one of the following: 0.1wt%–5wt% hydrochloric acid, 0.1wt%–5wt% sulfuric acid, or 0.1wt%–5wt% nitric acid.

4. The distillation system for preparing divinylbenzene as described in claim 1, characterized in that, The structured metal packing is selected from perforated plate corrugated packing, with a mesh size of 55-60 mesh.

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