Method for efficiently extracting organic chemical materials such as acetophenone from heavy aromatics

Abstract

The invention relates to the technical field of industrial chemistry and resource recovery, and discloses a method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatics, the method comprises the steps of raw material pretreatment, catalytic cracking reaction, rectification separation and condensation recovery, and the raw material pretreatment comprises the steps of mechanical filtration, dehydration treatment and preliminary fractionation; solid impurities and moisture in the heavy aromatic hydrocarbon raw material are removed, light components are separated out, pure raw materials are provided for subsequent catalytic cracking reaction, catalyst poisoning and reaction interference are avoided, and the stability and efficiency of the whole extraction process are guaranteed; a composite catalyst is adopted for catalytic cracking reaction, macromolecules in heavy aromatics are efficiently cracked to generate acetophenone, methyl styrene and other organic chemical materials under optimized pressure and temperature conditions, the catalyst has high activity and selectivity, and the yield and reaction rate of a target product are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of industrial chemistry and resource recovery technology, in particular to a method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons. BACKGROUND

[0002] In the traditional synthesis process of dicumyl peroxide, acetophenone, methylstyrene, dimethylbenzyl alcohol and the like are often mixed in the heavy aromatic hydrocarbon fraction with high boiling point and are not fully recovered and utilized, resulting in waste of resources; acetophenone and methylstyrene are important organic chemical raw materials, have a benzene ring and a substituent group structure, and have wide application in the fields of chemical industry, pharmaceuticals, organic synthesis, perfumes and high polymer materials, and have high economic value.

[0003] At present, in the production process of extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons, due to the complex composition of heavy aromatic hydrocarbon raw materials, often containing solid impurities, moisture and light components and the like, direct catalytic cracking reaction is easy to cause the activity of the catalyst to be reduced or even poisoned, affecting the reaction efficiency; at the same time, the existing catalytic cracking process has problems such as low selectivity of the catalyst and poor control of the reaction conditions, resulting in low yield of the target products acetophenone and methylstyrene.

[0004] Therefore, the present application provides a method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons to solve the above problems. SUMMARY

[0005] In view of the deficiencies of the prior art, the present application provides a method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons, which solves the problems of affected reaction efficiency and low yield of target products acetophenone and methylstyrene raised in the background art.

[0006] To achieve the above purpose, the present application provides the following technical solution: a method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons, comprising the following steps: Step 1: raw material pretreatment, selecting heavy aromatic hydrocarbon fraction from dicumyl peroxide synthesis process as raw material, removing solid impurities by mechanical filtration, then adding drying agent for dehydration treatment, and finally performing preliminary fractionation under vacuum to separate light components; Step 2: catalytic cracking reaction, heating the pretreated heavy aromatic hydrocarbon raw material to 122℃ and continuously feeding into the reaction zone of the catalytic rectification tower, the reaction zone is filled with HZSM-5 / SnO2 / SnCl4 composite catalyst, and the catalytic cracking reaction is carried out under the conditions of pressure 0.08-0.09 MPa and temperature 160-170℃, so that the macromolecules in the heavy aromatic hydrocarbons are cracked to generate acetophenone and methylstyrene and other organic chemical materials; Step 3: Distillation separation. Distillation separation is carried out simultaneously in a catalytic distillation column. By controlling the temperature gradient inside the column, low-boiling-point products such as acetophenone and methylstyrene are volatilized and separated from the top of the column, while heavy components remain at the bottom of the column. Step 4: Condensation and recovery. The gaseous product at the top of the column is condensed and cooled to below 30°C to obtain the liquid product, which is then collected and filtered to obtain high-purity acetophenone and methylstyrene products.

[0007] Preferably, the preprocessing in step one includes the following specific steps: First, a mechanical filter is used to filter the heavy aromatics feedstock to remove suspended solids and catalyst poisons, with a filtration accuracy of 5-10 microns. Then add 4A molecular sieve as a desiccant to the raw material, the amount of which is 6% of the raw material mass, and stir and dehydrate at room temperature for 2-4 hours; Finally, preliminary fractionation was carried out under a vacuum of 0.01-0.05 MPa at a temperature of 80-100℃ to separate light components such as cumene and phenol, which were then recovered and reused.

[0008] Preferably, the amount of 4A molecular sieve added is strictly controlled to 5%-8% of the raw material mass, and the dehydration time is adjusted according to the moisture content of the raw material, usually 2-4 hours, with a moisture content of less than 0.5%. The vacuum degree of the initial fractionation is controlled at 0.01-0.05 MPa, the fractionation temperature is adjusted to 80-100℃ by the reboiler, and the fractionation time is 1-2 hours to completely separate the light components.

[0009] Preferably, in step two, the composite catalyst uses HZSM-5 zeolite as a support, wherein the SiO2 / Al2O3 molar ratio is 50-60, and SnO2 and SnCl4 are used as modifying components, with SnO2 having a mass fraction of 8%-15% and SnCl4 having a mass fraction of 5%-10%. HZSM-5 zeolite has a grain size of 3-8 mm and a specific surface area of ​​300-400 m² / g, providing sufficient active centers.

[0010] Preferably, the preparation method of the composite catalyst includes: HZSM-5 zeolite carrier was impregnated in a solution containing SnO2 and SnCl4. The solution was prepared with deionized water, with 8-15g of SnO2 and 5-10g of SnCl4 added per 100g of deionized water to form a homogeneous slurry. Then, HZSM-5 zeolite was soaked in the slurry and stirred at room temperature for 1-3 hours. After being removed, it was baked at 140-150℃ for 3-6 hours to activate it, thus obtaining the supported composite catalyst.

[0011] Preferably, in step two, the operating pressure of the catalytic cracking reaction is controlled at 0.08-0.09 MPa, the reaction temperature is maintained at 160-170℃, and the reaction time is 0.5-4 hours; During the reaction, the catalyst loading accounts for 10%-30% of the volume of the reaction zone in the catalytic distillation column, and the space velocity is 0.5-5 h⁻¹. -1 .

[0012] Preferably, the distillation separation in step three is carried out in a catalytic distillation column, which has 50-70 theoretical plates, a distillation reflux ratio of 20:1-25:1, a top temperature of 110-130℃, and a top pressure of 0.02-0.05MPa.

[0013] Preferably, step four, condensation recovery, includes: The gaseous product at the top of the column is cooled to below 25°C by circulating cooling water in a condenser. The condensed liquid product enters the reflux tank. Part of the liquid is sent back to the top of the column by a reflux pump. The reflux ratio is controlled at 20:1-25:1. The remainder is continuously discharged from the bottom of the reflux tank as product. The product is then filtered through a precision filter to remove solid particles before entering the finished product tank for storage.

[0014] Preferably, after the pretreatment in step one, a polymerization inhibitor, p-tert-butylphenol, is added to the heavy aromatic hydrocarbon raw material. The amount added is 0.005%-0.02% of the raw material mass. It is mixed evenly with the raw material before feeding to prevent acetophenone and methylstyrene from undergoing polymerization reaction at high temperature.

[0015] Preferably, the packing material in the reaction zone of the catalytic distillation column is structured packing made of stainless steel, with a packing height of 1 / 3 to 2 / 3 of the column height. The catalyst is uniformly packed in granular form on the packing tray, resulting in uniform gas-liquid distribution and simultaneous reaction and separation.

[0016] Compared with existing technologies, this invention provides a method for efficiently extracting organic chemical materials such as acetophenone from heavy aromatic hydrocarbons, which has the following beneficial effects: 1. In this invention, through raw material pretreatment, including mechanical filtration, dehydration and preliminary fractionation, solid impurities and moisture in heavy aromatic raw materials are removed, and light components are separated, providing pure raw materials for subsequent catalytic cracking reactions, avoiding catalyst poisoning and reaction interference, and ensuring the stability and efficiency of the entire extraction process.

[0017] 2. In this invention, a composite catalyst is used for catalytic cracking reaction. Under optimized pressure and temperature conditions, macromolecules in heavy aromatic hydrocarbons are efficiently cracked to generate organic chemical materials such as acetophenone and methylstyrene. The catalyst has high activity and selectivity, which improves the yield and reaction rate of the target product.

[0018] 3. In this invention, the reaction and distillation separation are carried out simultaneously in a catalytic distillation column. By controlling the temperature gradient and reflux ratio in the column, the volatilization separation of low-boiling-point products such as acetophenone and methylstyrene is achieved. Combined with condensation recovery and filtration steps, high-purity products are obtained. At the same time, a polymerization inhibitor is added to prevent product polymerization, ensuring product quality and the reliability of continuous operation. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: A method for efficiently extracting organic chemical materials such as acetophenone from heavy aromatic hydrocarbons, comprising the following steps: Step 1: Raw material pretreatment. The heavy aromatic fraction from the dicumyl peroxide synthesis process is selected as raw material. It is mechanically filtered to remove solid impurities, then a desiccant is added for dehydration, and finally preliminary fractionation is carried out under vacuum to separate light components. Step 2: Catalytic cracking reaction. The pretreated heavy aromatics feedstock is heated to 122°C and then continuously fed into the reaction zone of the catalytic distillation column. The reaction zone is filled with HZSM-5 / SnO2 / SnCl4 composite catalyst. The catalytic cracking reaction is carried out under the conditions of 0.08MPa pressure and 160°C, so that the macromolecules in the heavy aromatics are cracked to generate organic chemical materials such as acetophenone and methylstyrene. Step 3: Distillation separation. Distillation separation is carried out simultaneously in a catalytic distillation column. By controlling the temperature gradient inside the column, low-boiling-point products such as acetophenone and methylstyrene are volatilized and separated from the top of the column, while heavy components remain at the bottom of the column. Step 4: Condensation and recovery. The gaseous product at the top of the column is condensed and cooled to below 30°C to obtain the liquid product, which is then collected and filtered to obtain high-purity acetophenone and methylstyrene products.

[0021] Step one of the preprocessing steps includes the following specific steps: First, a mechanical filter is used to filter the heavy aromatics feedstock to remove suspended solids and catalyst poisons, with a filtration accuracy of 5 microns. Then, 4A molecular sieve is added to the raw material as a desiccant, with an addition amount of 6% of the raw material mass, and the mixture is stirred and dehydrated at room temperature for 2 hours.

[0022] Finally, preliminary fractionation was carried out under a vacuum of 0.01 MPa at a fractionation temperature of 80°C to separate light components such as cumene and phenol, which were then recovered and reused.

[0023] The addition amount of 4A molecular sieve is strictly controlled at 5% of the raw material mass. The dehydration time is adjusted according to the moisture content of the raw material, usually 2 hours, with a moisture content of less than 0.5%. The vacuum degree of the initial fractionation is controlled at 0.01 MPa, the fractionation temperature is adjusted to 80°C by the reboiler, and the fractionation time is 1 hour to completely separate the light components.

[0024] In step two, the composite catalyst uses HZSM-5 zeolite as a support, with a SiO2 / Al2O3 molar ratio of 50, and SnO2 and SnCl4 as modifying components, with SnO2 having a mass fraction of 8% and SnCl4 having a mass fraction of 5%. HZSM-5 zeolite has a grain size of 3mm and a specific surface area of ​​300m² / g, providing sufficient active centers.

[0025] Methods for preparing composite catalysts include: HZSM-5 zeolite carrier was impregnated in a solution containing SnO2 and SnCl4. The solution was prepared with deionized water, with 8g of SnO2 and 5g of SnCl4 added per 100g of deionized water to form a homogeneous slurry. Then, HZSM-5 zeolite was soaked in the slurry and stirred at room temperature for 1 hour. After being removed, it was baked at 140℃ for 3 hours to activate it, thus obtaining the supported composite catalyst.

[0026] In step two, the operating pressure of the catalytic cracking reaction is controlled at 0.08 MPa, the reaction temperature is maintained at 160℃, and the reaction time is 0.5 hours. During the reaction, the catalyst loading accounts for 10% of the reaction zone volume of the catalytic distillation column, and the space velocity is 0.5 h⁻¹. -1 To optimize reaction efficiency.

[0027] In step three, the distillation separation is carried out in a catalytic distillation column, which has 50 theoretical plates, a distillation reflux ratio of 20:1, a top temperature of 110℃, and a top pressure of 0.02MPa.

[0028] Step four, condensation recovery, includes: The gaseous product at the top of the column is cooled to below 25°C by circulating cooling water in a condenser. The condensed liquid product enters the reflux tank. Part of the liquid is sent back to the top of the column by a reflux pump. The reflux ratio is controlled at 20:1. The remainder is continuously discharged from the bottom of the reflux tank as product. The product then passes through a precision filter to remove solid particles before entering the finished product tank for storage.

[0029] After the pretreatment in step one, a polymerization inhibitor, p-tert-butylphenol, is added to the heavy aromatic hydrocarbon raw material at a rate of 0.005% of the raw material mass. It is mixed evenly with the raw material before feeding to prevent acetophenone and methylstyrene from undergoing polymerization at high temperatures.

[0030] The reaction zone packing of the catalytic distillation column is a structured packing made of stainless steel. The packing height is 1 / 3 of the column height. The catalyst is uniformly packed in granular form on the packing tray to ensure uniform gas-liquid distribution and simultaneous reaction and separation.

[0031] Example 2: A method for efficiently extracting organic chemical materials such as acetophenone from heavy aromatic hydrocarbons, comprising the following steps: Step 1: Raw material pretreatment. The heavy aromatic fraction from the dicumyl peroxide synthesis process is selected as raw material. It is mechanically filtered to remove solid impurities, then a desiccant is added for dehydration, and finally preliminary fractionation is carried out under vacuum to separate light components. Step 2: Catalytic cracking reaction. The pretreated heavy aromatics feedstock is heated to 122°C and then continuously fed into the reaction zone of the catalytic distillation column. The reaction zone is filled with HZSM-5 / SnO2 / SnCl4 composite catalyst. The catalytic cracking reaction is carried out under the conditions of 0.085MPa pressure and 165°C, so that the macromolecules in the heavy aromatics are cracked to generate organic chemical materials such as acetophenone and methylstyrene. Step 3: Distillation separation. Distillation separation is carried out simultaneously in a catalytic distillation column. By controlling the temperature gradient inside the column, low-boiling-point products such as acetophenone and methylstyrene are volatilized and separated from the top of the column, while heavy components remain at the bottom of the column. Step 4: Condensation and recovery. The gaseous product at the top of the column is condensed and cooled to below 30°C to obtain the liquid product, which is then collected and filtered to obtain high-purity acetophenone and methylstyrene products.

[0032] Step one of the preprocessing steps includes the following specific steps: First, a mechanical filter is used to filter the heavy aromatics feedstock to remove suspended solids and catalyst poisons, with a filtration accuracy of 8 microns. Then, 4A molecular sieve is added to the raw material as a desiccant, with an addition amount of 6% of the raw material mass, and the mixture is stirred and dehydrated at room temperature for 3 hours. Finally, preliminary fractionation was carried out under a vacuum of 0.03 MPa at a temperature of 90°C to separate light components such as cumene and phenol, which were then recovered and reused.

[0033] The addition amount of 4A molecular sieve is strictly controlled at 6.5% of the raw material mass. The dehydration time is adjusted according to the moisture content of the raw material, usually 3 hours, with a moisture content of less than 0.5%. The vacuum degree of the initial fractionation is controlled at 0.03 MPa, the fractionation temperature is adjusted to 90°C by the reboiler, and the fractionation time is 1.5 hours to completely separate the light components.

[0034] In step two, the composite catalyst uses HZSM-5 zeolite as a support, with a SiO2 / Al2O3 molar ratio of 55, and SnO2 and SnCl4 as modifying components, with SnO2 having a mass fraction of 12% and SnCl4 having a mass fraction of 8%. HZSM-5 zeolite has a grain size of 5 mm and a specific surface area of ​​350 m² / g, providing sufficient active centers.

[0035] Methods for preparing composite catalysts include: HZSM-5 zeolite carrier was impregnated in a solution containing SnO2 and SnCl4. The solution was prepared with deionized water, with 12g of SnO2 and 8g of SnCl4 added per 100g of deionized water to form a homogeneous slurry. Then, HZSM-5 zeolite was soaked in the slurry and stirred at room temperature for 2 hours. After being removed, it was baked at 145℃ for 4.5 hours to activate it, thus obtaining the supported composite catalyst.

[0036] In step two, the operating pressure of the catalytic cracking reaction is controlled at 0.085 MPa, the reaction temperature is maintained at 165℃, and the reaction time is 2.2 hours. During the reaction, the catalyst loading occupies 20% of the reaction zone volume of the catalytic distillation column, and the space velocity is 2.7 h⁻¹. -1 To optimize reaction efficiency.

[0037] In step three, the distillation separation is carried out in a catalytic distillation column, which has 60 theoretical plates, a distillation reflux ratio of 23:1, a top temperature of 120℃, and a top pressure of 0.035MPa.

[0038] Step four, condensation recovery, includes: The gaseous product at the top of the column is cooled to below 25°C by circulating cooling water in a condenser. The condensed liquid product enters the reflux tank. Part of the liquid is sent back to the top of the column by a reflux pump. The reflux ratio is controlled at 23:1. The remainder is continuously discharged from the bottom of the reflux tank as product. The product then passes through a precision filter to remove solid particles before entering the finished product tank for storage.

[0039] After the pretreatment in step one, a polymerization inhibitor, p-tert-butylphenol, is added to the heavy aromatic hydrocarbon raw material at a rate of 0.012% of the raw material mass. The additive is mixed evenly with the raw material before feeding to prevent acetophenone and methylstyrene from undergoing polymerization at high temperatures.

[0040] The reaction zone packing of the catalytic distillation column is a structured packing made of stainless steel. The packing height is 1 / 2 of the column height. The catalyst is uniformly packed in granular form on the packing tray to ensure uniform gas-liquid distribution and simultaneous reaction and separation.

[0041] Example 3: A method for efficiently extracting organic chemical materials such as acetophenone from heavy aromatic hydrocarbons, comprising the following steps: Step 1: Raw material pretreatment. The heavy aromatic fraction from the dicumyl peroxide synthesis process is selected as raw material. It is mechanically filtered to remove solid impurities, then a desiccant is added for dehydration, and finally preliminary fractionation is carried out under vacuum to separate light components. Step 2: Catalytic cracking reaction. The pretreated heavy aromatics feedstock is heated to 122°C and then continuously fed into the reaction zone of the catalytic distillation column. The reaction zone is filled with HZSM-5 / SnO2 / SnCl4 composite catalyst. The catalytic cracking reaction is carried out under the conditions of 0.09MPa pressure and 170°C, so that the macromolecules in the heavy aromatics are cracked to generate organic chemical materials such as acetophenone and methylstyrene. Step 3: Distillation separation. Distillation separation is carried out simultaneously in a catalytic distillation column. By controlling the temperature gradient inside the column, low-boiling-point products such as acetophenone and methylstyrene are volatilized and separated from the top of the column, while heavy components remain at the bottom of the column. Step 4: Condensation and recovery. The gaseous product at the top of the column is condensed and cooled to below 30°C to obtain the liquid product, which is then collected and filtered to obtain high-purity acetophenone and methylstyrene products.

[0042] Step one of the preprocessing steps includes the following specific steps:

[0043] First, a mechanical filter is used to filter the heavy aromatics feedstock to remove suspended solids and catalyst poisons, with a filtration precision of 10 microns. Then, 4A molecular sieve is added to the raw material as a desiccant, with an addition amount of 6% of the raw material mass, and the mixture is stirred and dehydrated at room temperature for 4 hours. Finally, preliminary fractionation was carried out under a vacuum of 0.05 MPa at a fractionation temperature of 100℃ to separate light components such as cumene and phenol, which were then recovered and reused.

[0044] The addition amount of 4A molecular sieve is strictly controlled at 8% of the raw material mass. The dehydration time is adjusted according to the moisture content of the raw material, usually 4 hours, with a moisture content of less than 0.5%. The vacuum degree of the initial fractionation is controlled at 0.05 MPa, the fractionation temperature is adjusted to 100℃ by the reboiler, and the fractionation time is 2 hours to completely separate the light components.

[0045] In step two, the composite catalyst uses HZSM-5 zeolite as a support, with a SiO2 / Al2O3 molar ratio of 60, and SnO2 and SnCl4 as modifying components, with SnO2 having a mass fraction of 15% and SnCl4 having a mass fraction of 10%. HZSM-5 zeolite has a grain size of 8 mm and a specific surface area of ​​400 m² / g, providing sufficient active centers.

[0046] Methods for preparing composite catalysts include: HZSM-5 zeolite carrier was impregnated in a solution containing SnO2 and SnCl4. The solution was prepared with deionized water, with 15g of SnO2 and 10g of SnCl4 added per 100g of deionized water to form a homogeneous slurry. Then, HZSM-5 zeolite was soaked in the slurry and stirred at room temperature for 3 hours. After being removed, it was baked at 150°C for 6 hours to activate it, thus obtaining the supported composite catalyst.

[0047] In step two, the operating pressure of the catalytic cracking reaction is controlled at 0.09 MPa, the reaction temperature is maintained at 170℃, and the reaction time is 4 hours. During the reaction, the catalyst loading occupies 30% of the reaction zone volume of the catalytic distillation column, and the space velocity is 5 h⁻¹. -1 To optimize reaction efficiency.

[0048] In step three, the distillation separation is carried out in a catalytic distillation column, which has 70 theoretical plates, a distillation reflux ratio of 25:1, a top temperature of 130℃, and a top pressure of 0.05MPa.

[0049] Step four, condensation recovery, includes: The gaseous product at the top of the column is cooled to below 25°C by circulating cooling water in a condenser. The condensed liquid product enters the reflux tank. Part of the liquid is sent back to the top of the column by a reflux pump. The reflux ratio is controlled at 25:1. The remainder is continuously discharged from the bottom of the reflux tank as product. The product then passes through a precision filter to remove solid particles before entering the finished product tank for storage.

[0050] After the pretreatment in step one, a polymerization inhibitor, p-tert-butylphenol, is added to the heavy aromatic raw material at a rate of 0.02% of the raw material mass. It is mixed evenly with the raw material before feeding to prevent acetophenone and methylstyrene from undergoing polymerization at high temperatures.

[0051] The reaction zone packing of the catalytic distillation column is a structured packing made of stainless steel. The packing height is 2 / 3 of the column height. The catalyst is uniformly packed in granular form on the packing tray to ensure uniform gas-liquid distribution and simultaneous reaction and separation.

[0052] Comparative Example 1: The difference between this comparative example and Example 1 is that no SnO2 modification component was added when preparing the impregnation solution of the catalyst in this comparative example.

[0053] Comparative Example 2 differs from Example 1 in that SnCl4 modification component was not added when preparing the impregnation solution for the catalyst in this comparative example.

[0054] Comparative Example 3 differs from Example 1 in that the heavy aromatic hydrocarbon feedstock in this comparative example was not dehydrated.

[0055] Comparative Example 4 differs from Example 1 in that the polymerization inhibitor p-tert-butylphenol was not added to this comparative example.

[0056] The methods for efficiently extracting acetophenone and other organic chemical materials from heavy aromatics implemented in Examples 1-3 and Comparative Examples 1-4 were tested for performance. The test items and test methods are as follows: Acetophenone yield test: Catalytic cracking reaction was carried out under standard reaction conditions. After the reaction was completed, the top product of the column was collected, weighed, and the percentage of acetophenone mass relative to the feed mass was calculated. The yield test of methylstyrene was carried out under standard reaction conditions. After the reaction was completed, the top product of the column was collected, weighed, and the percentage of methylstyrene mass relative to the mass of the feed was calculated. Product purity testing was performed using a gas chromatograph equipped with an FID detector, a DB-5 column, and a column temperature program that increased from 60℃ to 250℃. The peak areas of acetophenone and methylstyrene were measured, and the purity percentage was calculated. The reaction efficiency was tested by using online analysis to monitor the conversion rate of raw materials during the reaction process.

[0057] Group Acetophenone yield (%) Methylstyrene yield (%) Product purity (wt%) Feedstock conversion (%) Example 1 88.5 85.2 99.2 95.8 Example 2 92.1 89.7 99.5 98.3 Example 3 90.3 87.4 99.3 97.1 Comparative Example 1 75.6 72.3 97.8 85.4 Comparative Example 2 78.9 74.8 98.1 87.6 Comparative Example 3 65.2 60.1 95.5 80.2 Comparative Example 4 82.4 79.5 92.3 93.5 ; By comparing and analyzing the data in the table, it can be seen that the methods in Examples 1-3 for extracting acetophenone and other organic chemical materials from heavy aromatics are significantly superior to those in Comparative Examples 1-4. This indicates that the present invention, through raw material pretreatment, including mechanical filtration, dehydration, and preliminary fractionation, removes solid impurities and moisture from the heavy aromatic raw materials and separates light components, providing pure raw materials for subsequent catalytic cracking reactions, avoiding catalyst poisoning and reaction interference, and ensuring the stability and efficiency of the entire extraction process. The use of a composite catalyst for catalytic cracking, under optimized pressure and temperature conditions, enables the efficient cracking of macromolecules in heavy aromatics to generate acetophenone and methylstyrene, among other organic chemical materials. The catalyst exhibits high activity and selectivity, improving the yield and reaction rate of the target product. Simultaneous reaction and distillation separation are carried out in a catalytic distillation column. By controlling the temperature gradient and reflux ratio within the column, the volatilization and separation of low-boiling-point products such as acetophenone and methylstyrene are achieved. Combined with condensation recovery and filtration steps, high-purity products are obtained. Simultaneously, a polymerization inhibitor is added to prevent product polymerization, ensuring product quality and the reliability of continuous operation.

[0058] By comparing and analyzing the relevant data in the table, it can be seen that the method of the present invention has a high yield and purity in extracting organic chemical materials such as acetophenone from heavy aromatic hydrocarbons.

[0059] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0060] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for efficiently extracting organic chemical materials such as acetophenone from heavy aromatic hydrocarbons, characterized in that: Includes the following steps: Step 1: Raw material pretreatment. The heavy aromatic fraction from the dicumyl peroxide synthesis process is selected as raw material. It is mechanically filtered to remove solid impurities, then a desiccant is added for dehydration, and finally preliminary fractionation is carried out under vacuum to separate light components. Step 2: Catalytic cracking reaction. The pretreated heavy aromatics feedstock is heated to 122°C and then continuously fed into the reaction zone of a catalytic distillation column. The reaction zone is filled with an HZSM-5 / SnO2 / SnCl4 composite catalyst. The catalytic cracking reaction is carried out under the conditions of 0.08-0.09 MPa pressure and 160-170°C, so that the macromolecules in the heavy aromatics are cracked to generate organic chemical materials such as acetophenone and methylstyrene. Step 3: Distillation separation. Distillation separation is carried out simultaneously in the catalytic distillation column. By controlling the temperature gradient inside the column, low-boiling-point products such as acetophenone and methylstyrene are volatilized and separated from the top of the column, while heavy components remain at the bottom of the column. Step 4: Condensation and recovery. The gaseous product at the top of the column is condensed and cooled to below 30°C to obtain the liquid product, which is then collected and filtered to obtain high-purity acetophenone and methylstyrene products.

2. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons according to claim 1, characterized in that: The preprocessing in step one includes the following specific steps: First, a mechanical filter is used to filter the heavy aromatics feedstock to remove suspended solids and catalyst poisons, with a filtration accuracy of 5-10 microns. Then add 4A molecular sieve as a desiccant to the raw material, the amount of which is 6% of the raw material mass, and stir and dehydrate at room temperature for 2-4 hours; Finally, preliminary fractionation was carried out under a vacuum of 0.01-0.05 MPa at a temperature of 80-100℃ to separate light components such as cumene and phenol, which were then recovered and reused.

3. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons according to claim 2, characterized in that: The amount of 4A molecular sieve added is strictly controlled to be 5%-8% of the raw material mass. The dehydration time is adjusted according to the moisture content of the raw material, usually 2-4 hours, with a moisture content of less than 0.5%. The vacuum degree of the preliminary fractionation is controlled at 0.01-0.05 MPa, the fractionation temperature is adjusted to 80-100℃ by the reboiler, and the fractionation time is 1-2 hours to completely separate the light components.

4. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatics according to claim 1, characterized in that: In step two, the composite catalyst uses HZSM-5 zeolite as a support, with a SiO2 / Al2O3 molar ratio of 50-60, and SnO2 and SnCl4 as modifying components, with SnO2 having a mass fraction of 8%-15% and SnCl4 having a mass fraction of 5%-10%. The HZSM-5 zeolite has a grain size of 3-8 mm and a specific surface area of ​​300-400 m² / g, providing sufficient active centers.

5. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatics according to claim 4, characterized in that: The preparation method of the composite catalyst includes: HZSM-5 zeolite carrier was impregnated in a solution containing SnO2 and SnCl4, the solution being prepared with deionized water, with 8-15g of SnO2 and 5-10g of SnCl4 added per 100g of deionized water to form a homogeneous slurry. Then, HZSM-5 zeolite was soaked in the slurry and stirred at room temperature for 1-3 hours. After being removed, it was baked at 140-150℃ for 3-6 hours to activate it, thus obtaining the supported composite catalyst.

6. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatics according to claim 1, characterized in that: In step two, the operating pressure of the catalytic cracking reaction is controlled at 0.08-0.09 MPa, the reaction temperature is maintained at 160-170℃, and the reaction time is 0.5-4 hours. During the reaction, the catalyst loading accounts for 10%-30% of the volume of the reaction zone in the catalytic distillation column, and the space velocity is 0.5-5 h⁻¹. -1 .

7. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons according to claim 1, characterized in that: In step three, the distillation separation is carried out in a catalytic distillation column, which has 50-70 theoretical plates, a distillation reflux ratio of 20:1-25:1, a top temperature of 110-130℃, and a top pressure of 0.02-0.05MPa.

8. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons according to claim 1, characterized in that: The condensation and recovery in step four includes: The gaseous product at the top of the column is cooled to below 25°C by circulating cooling water in a condenser. The condensed liquid product enters the reflux tank. Part of the liquid is sent back to the top of the column by a reflux pump. The reflux ratio is controlled at 20:1-25:

1. The remainder is continuously discharged from the bottom of the reflux tank as product. The product is then filtered through a precision filter to remove solid particles before entering the finished product tank for storage.

9. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons according to claim 1, characterized in that: After the pretreatment in step one, a polymerization inhibitor, p-tert-butylphenol, is added to the heavy aromatic hydrocarbon raw material. The amount added is 0.005%-0.02% of the raw material mass. It is mixed evenly with the raw material before feeding to prevent acetophenone and methylstyrene from undergoing polymerization reaction at high temperature.

10. The method for efficiently extracting acetophenone and other organic chemical materials from heavy aromatic hydrocarbons according to claim 1, characterized in that: The reaction zone packing of the catalytic distillation column is a structured packing made of stainless steel. The packing height is 1 / 3 to 2 / 3 of the column height. The catalyst is uniformly packed in granular form on the packing tray, resulting in uniform gas-liquid distribution and simultaneous reaction and separation.