A process for the production of di- and tri-isobutene based on isobutene

Abstract

A method for producing diisobutylene and triisobutylene based on isobutylene, first, a metal ion modified strong acid cation exchange resin is placed in a polymerization reactor and a catalytic distillation column; then fresh isobutylene raw material, a part of the reaction product output from the polymerization reactor and a part of the unreacted isobutylene output from the catalytic distillation column are jointly fed into the polymerization reactor for polymerization reaction, a part of the obtained reaction product enters the catalytic distillation column for polymerization reaction, and finally the obtained reaction product is transported to a diisobutylene rectification column, diisobutylene is obtained at the top of the column, and the bottom material is transported to a triisobutylene rectification column, triisobutylene is obtained at the top of the column. The method uses a metal ion modified strong acid cation exchange resin as a catalyst, reduces the activity of the catalyst, makes the polymerization reaction of isobutylene more easily controllable, does not need to add an inhibitor during the reaction process, saves the separation device of the inhibitor, is simple to operate, and produces triisobutylene as a byproduct while producing diisobutylene.

Description

Technical Field

[0001] This invention belongs to the field of isobutylene polymerization technology, specifically relating to a method for producing diisobutylene and triisobutylene based on isobutylene. Background Technology

[0002] Isobutylene is an important chemical raw material, mainly used in the synthesis of methyl tert-butyl ether. The dimer of isobutylene (diisobutylene, a mixture of 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl-2-pentene, abbreviated as DIB) can be used to synthesize isononanol, isononanoic acid, p-octylphenol, surfactants, and other chemicals, and can also be used as a gasoline fuel additive and rubber additive. The trimer of isobutylene (triisobutylene, a mixture of 2-neopentyl-4,4-dimethyl-1-pentene and 2,2,4,6,6-pentamethyl-3-heptene, abbreviated as TIB) can be used as a diesel fuel additive and has a very wide range of applications in the synthesis of specialty chemicals.

[0003] There are two main methods for preparing diisobutylene. One method involves selectively reacting isobutylene from the C4 fraction produced by FCC or ethylene production equipment with sulfuric acid to separate it from 1-butene, 2-butene, butane, etc., in the form of isobutyl sulfate. Diisobutylene is then obtained through heating and decomposition. The other method involves converting isobutylene from the C4 fraction into methyl tert-butyl ether and tert-butanol, followed by decomposition and dimerization to obtain diisobutylene. The former method, in addition to the target product diisobutylene, involves numerous side reactions, generating a large number of trimers, tetramers, and other byproducts. Furthermore, because sulfuric acid is involved in the reaction, the equipment requires corrosion-resistant materials. The latter method requires the addition of inhibitors during the isobutylene dimerization reaction. The inhibitors are typically separated by water washing or distillation. Although the yield of diisobutylene is higher in this method, the process is longer and more complex.

[0004] For example, Chinese Patent (Publication No. 111606772A) reports a method and apparatus for isobutylene superposition reaction, in which a mixture of C4, tert-butanol and water is passed through two reactors connected in series. The reactors are filled with cation exchange resin catalysts, and the reaction is a gas-liquid mixed-phase reaction, with a diisobutylene yield of about 80%.

[0005] For example, Chinese patent (publication number 1356300A) reports a method for preparing diisobutylene, which uses isobutylene as raw material and modified sulfonic acid cation exchange resin as catalyst to carry out liquid-phase selective oligomerization reaction. The catalyst is modified by acetone soaking, hydrochloric acid exchange, water washing and ethanol soaking, and vacuum treatment process, and the yield of diisobutylene obtained is 66-82%.

[0006] For example, Chinese patent (publication number 104815695A) reports a method for preparing diisobutylene by catalysis using a carbon nanotube-supported ionic liquid catalyst. The isobutylene is dried by a dryer using a 5A molecular sieve and then undergoes oligomerization reaction in a fixed-bed reactor containing a catalyst at 100°C and 0.6 MPa. The yield of the obtained diisobutylene is >85%.

[0007] It is evident that in existing technologies, the polymerization of isobutylene primarily utilizes strongly acidic cation exchange resins as catalysts. Other types of catalysts suffer from difficulties in preparation methods and low selectivity for diisobutylene. Industrial production of diisobutylene mainly employs fixed-bed reactors, which generate large amounts of polymer byproducts during the process. Furthermore, the reaction is highly exothermic, easily causing overheating in the fixed-bed reactor, making operation difficult. Additionally, methanol or tert-butanol are used as inhibitors to improve diisobutylene selectivity, further complicating subsequent separation. Summary of the Invention

[0008] In view of this, the present invention addresses the technical problems of existing methods for preparing diisobutylene by isobutylene polymerization, such as difficulties in catalyst preparation, low selectivity of diisobutylene, numerous by-products, high operational difficulty, and difficult product separation. It provides a method for producing diisobutylene and triisobutylene based on isobutylene.

[0009] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows.

[0010] This invention provides a method for producing diisobutylene and triisobutylene based on isobutylene, the steps of which are as follows:

[0011] Step 1: Place the metal ion-modified strong acid cation exchange resin into the polymerization reactor and the catalyst distillation column;

[0012] Step 2: Fresh isobutylene feedstock, a portion of the reaction product from the polymerization reactor, and a portion of unreacted isobutylene from the catalytic distillation column are fed into the polymerization reactor for polymerization. The mass of fresh isobutylene feedstock is 15-22%, the mass of the reaction product from the polymerization reactor is 75-80%, and the mass of unreacted isobutylene from the catalytic distillation column is 3-5%. The resulting reaction product is divided into two parts: one part is mixed with the fresh isobutylene feedstock and the unreacted isobutylene from the catalytic distillation column before entering the polymerization reactor, and the other part enters the catalytic distillation column.

[0013] Step 3: The reaction products entering the catalytic distillation tower continue to undergo polymerization in the catalytic distillation tower. The resulting reaction products are sent to the diisobutylene purification tower. Part of the unreacted isobutylene is returned to the catalytic distillation tower, and the other part is mixed with fresh isobutylene raw material and part of the reaction products output from the polymerization reactor before entering the polymerization reactor.

[0014] Step 4: The diisobutylene refining tower purifies the incoming reaction product, obtaining diisobutylene at the top of the tower, and the material at the bottom of the tower is conveyed to the triisobutylene refining tower.

[0015] Step 5: The triisobutylene refining column refines the bottom material entering the column, and triisobutylene is obtained at the top of the column.

[0016] Preferably, the preparation method of the metal ion-modified strong acid cation exchange resin is as follows:

[0017] 1a) Dissolve the metal salt in deionized water to obtain a metal salt solution;

[0018] 1b) Mix the strong acid cation exchange resin with the metal salt solution until uniform, let stand to obtain the ion exchange resin, drain the water, wash until there are no metal salt anions, dry to obtain the metal ion modified strong acid cation exchange resin.

[0019] More preferably, the metal salt is a nitrate, sulfate, or chloride, and the metal is nickel, copper, or zinc; zinc chloride is particularly preferred.

[0020] More preferably, the strong acid cation exchange resin has a particle size ≥1.5 mm and a water content of 50-55%.

[0021] More preferably, the molar ratio of the metal ions of the metal salt to the sulfonic acid groups of the strong acid cation exchange resin is 10-15:50.

[0022] More preferably, in step 1b), the settling time is 30 to 40 minutes.

[0023] More preferably, in step 1b), the drying temperature is 60-70°C and the drying time is 8-12 hours.

[0024] Preferably, in step two, the inlet temperature of the polymerization reactor is 55-60°C, the outlet temperature is 75-80°C, the reaction pressure is 1-1.2 MPa, and the isobutylene conversion rate is 50-55%.

[0025] Preferably, in step two, 75-80% of the reaction product is mixed with fresh isobutylene feedstock and a portion of unreacted isobutylene output from the catalytic distillation column before entering the polymerization reactor, and 20-25% of the reaction product enters the catalytic distillation column. More preferably, 75-80% of the reaction product is mixed with fresh isobutylene feedstock and a portion of unreacted isobutylene output from the catalytic distillation column by pumping, and 20-25% of the reaction product enters the catalytic distillation column by pressure difference.

[0026] Preferably, in step three, 50-60% of the unreacted isobutylene is refluxed to the catalytic distillation column, and 40-50% of the unreacted isobutylene is mixed with fresh isobutylene feedstock and a portion of the reaction products output from the polymerization reactor before entering the polymerization reactor.

[0027] Preferably, in step three, the pressure of the catalytic distillation column is 0.45-0.5 MPa, the top temperature is 42-45°C, the bottom temperature is 130-135°C, and the top reflux ratio is 1-1.5:1.

[0028] Preferably, in step three, a cylindrical catalyst loading container is fixed inside the catalytic distillation column for loading a metal ion-modified strong acid cation exchange resin. The outer diameter of the catalyst loading container is fitted with the inner diameter of the catalytic distillation column with a clearance. The height of the catalyst loading container is 1.5 to 2 times its outer diameter. The catalyst loading container has through holes with a diameter of 0.5 to 1.5 mm evenly distributed on it.

[0029] More preferably, the lower surface of the catalyst packing container is located in the middle of the catalytic distillation column, and the total height of the catalyst packing container is 20% to 25% of the height of the catalytic distillation column section.

[0030] More preferably, the catalyst filling container is made of stainless steel.

[0031] Preferably, in step four, the diisobutylene refining column is operated under normal pressure or slightly positive pressure, with a pressure of 0.1 to 0.15 MPa, a top temperature of 102 to 104°C, a bottom temperature of 175 to 180°C, and a diisobutylene content at the top of the column > 99%.

[0032] Preferably, in step five, the triisobutylene refining column is operated under negative pressure with a pressure of -1 to -1.5 kPa, a top temperature of 70 to 75°C, a bottom temperature of 110 to 120°C, and a triisobutylene content at the top of the column > 92%.

[0033] Compared with the prior art, the beneficial effects of the present invention are at least in the following aspects:

[0034] Firstly, the method for producing diisobutylene and triisobutylene based on isobutylene provided by this invention does not require the addition of inhibitors, saving the inhibitor separation device, and the product separation process is simple, producing triisobutylene as a byproduct while producing diisobutylene.

[0035] Secondly, the method for producing diisobutylene and triisobutylene based on isobutylene provided by this invention uses a metal ion-modified strong acid cation exchange resin as the catalyst, which reduces the catalyst activity, facilitates the control of the polymerization degree of isobutylene, and simplifies the operation.

[0036] Third, the method for producing diisobutylene and triisobutylene based on isobutylene provided by the present invention uses an external circulation method to reduce the isobutylene content at the inlet of the polymerization reactor, which facilitates the control of the temperature rise of the polymerization reactor and prevents overheating. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained without creative effort.

[0038] Figure 1 This is a process flow diagram of the method for producing diisobutylene and triisobutylene based on isobutylene according to the present invention;

[0039] In the diagram, 1. Polymerization reactor, 2. Catalytic distillation column, 3. Diisobutylene refining column, 4. Triisobutylene refining column, 5. First pipeline, 6. Second pipeline, 7. Third pipeline, 8. Fourth pipeline, 9. Fifth pipeline, 10. Sixth pipeline, 11. Seventh pipeline, 12. Eighth pipeline, 13. Ninth pipeline, 14. Tenth pipeline. Detailed Implementation

[0040] To further understand the present invention, preferred embodiments of the present invention are described below. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0041] like Figure 1 As shown, the method for producing diisobutylene and triisobutylene based on isobutylene according to the present invention comprises the following steps:

[0042] Step 1: First, place the metal ion-modified strong acid cation exchange resin into polymerization reactor 1 and catalytic distillation tower 2;

[0043] Step 2: Fresh isobutylene feedstock supplied via the first pipeline 5, a portion of the reaction product output from polymerization reactor 1 supplied via the second pipeline 6, and a portion of unreacted isobutylene output from catalytic distillation tower 2 supplied via the fifth pipeline 9 are fed into polymerization reactor 1 for polymerization reaction. The resulting reaction product is divided into two parts. One part (external circulation material) is fed into the first pipeline 5 via the second pipeline 6, mixed with fresh isobutylene feedstock and a portion of unreacted isobutylene output from catalytic distillation tower 2, and then enters polymerization reactor 1. The other part enters catalytic distillation tower 2.

[0044] Step 3: The reaction products entering the catalytic distillation tower 2 continue to undergo polymerization in the catalytic distillation tower 2. The resulting reaction products are transported to the diisobutylene purification tower 3 via the sixth pipeline 10. Part of the unreacted isobutylene is returned to the catalytic distillation tower 2 via the fourth pipeline 8, and the other part is transported to the first pipeline 5 via the fifth pipeline 9. It is then mixed with fresh isobutylene raw material and part of the reaction products output from the polymerization reactor 1 before entering the polymerization reactor 1.

[0045] Step 4: The diisobutylene refining tower 3 refines the reaction product and obtains diisobutylene at the top of the tower, which is output through the seventh pipeline 11. The material at the bottom of the tower is transported to the triisobutylene refining tower 4 through the eighth pipeline 12.

[0046] Step 5: Triisobutylene refining tower 4 refines the bottom material and obtains triisobutylene at the top of the tower, which is output through the ninth pipeline 13. The bottom material (heavy component) is discharged through the tenth pipeline 14.

[0047] In the above technical solution, in step one, the metal ion-modified strong acid cation exchange resin is used as a catalyst and is prepared by the following method:

[0048] 1a) Dissolve the metal salt in deionized water to obtain a metal salt solution;

[0049] 1b) Mix the strong acid cation exchange resin with the metal salt solution evenly, let it stand to obtain the ion exchange resin, drain the excess water, wash until there are no metal salt anions, dry it to obtain the metal ion modified strong acid cation exchange resin.

[0050] In the above method, the amount of deionized water used in step 1a) is not particularly limited, as long as it is sufficient to dissolve the metal salt. The metal salt is preferably a nitrate, sulfate, or chloride, and the metal is nickel, copper, or zinc; zinc chloride is more preferred. The strongly acidic cation exchange resin in step 1b) is existing technology and can be commercially available. The particle size of the strongly acidic cation exchange resin is preferably ≥1.5 mm, the water content is preferably 50-55%, and the main exchange groups of the strongly acidic cation exchange resin are sulfonic acid groups. The molar ratio of the metal ions in the metal salt to the sulfonic acid groups of the strongly acidic cation exchange resin is preferably 10-15:50. There are no particular limitations on the method of uniform mixing, but stirring is preferred. The standing time is preferably 30-40 min. The drying temperature is preferably 60-70℃, and the drying time is preferably 8-12 h.

[0051] In the above technical solution, in step one, the inlet temperature of the polymerization reactor 1 is preferably 55-60℃, the outlet temperature is preferably 75-80℃, the reaction pressure is preferably 1-1.2MPa, and the isobutylene conversion rate is preferably 50-55%.

[0052] In the above technical solution, in step two, 75-80% of the reaction product is mixed with fresh isobutylene raw material and a portion of unreacted isobutylene output from catalytic distillation tower 2 before entering polymerization reactor 1, and 20-25% of the reaction product enters catalytic distillation tower 2. Preferably, 75-80% of the reaction product is mixed with fresh isobutylene raw material and a portion of unreacted isobutylene output from catalytic distillation tower by pumping, and 20-25% of the reaction product enters catalytic distillation tower 2 by pressure difference.

[0053] In the above technical solution, in step three, 50-60% of the unreacted isobutylene is refluxed into catalytic distillation column 2, and 40-50% of the unreacted isobutylene is mixed with fresh isobutylene feedstock and a portion of the reaction products output from polymerization reactor 1 before entering polymerization reactor 1. The pressure of catalytic distillation column 2 is preferably 0.45-0.5 MPa, the top temperature is preferably 42-45°C, the bottom temperature is preferably 130-135°C, and the top reflux ratio is preferably 1:1. A cylindrical catalyst loading container is preferably fixed inside the catalytic distillation column 2 for filling with metal ion-modified strong acid cation exchange resin. The catalyst loading container has evenly distributed through holes with a diameter of 0.5–1.5 mm. The outer diameter of the catalyst loading container is fitted with a clearance fit to the inner diameter of the catalytic distillation column 2. The height of the catalyst loading container is 1.5–2 times its outer diameter. The lower surface of the catalyst loading container is located in the middle of the catalytic distillation column 2. The total height of the catalyst loading container is 20%–25% of the column section height of the catalytic distillation column 2. The catalyst loading container is preferably made of stainless steel. Typically, the catalyst loading container can be a cage with snap fasteners and numerous through holes. Three snap fasteners are fixed to the outer edge of the top opening of the cage body, arranged in an equilateral triangle. The snap fasteners are used to secure the cage cover and the cage body.

[0054] In the above technical solution, in step four, the preferred diisobutylene refining tower is operated under normal pressure or slightly positive pressure, with a pressure of 0.1 to 0.15 MPa, a top temperature of 102 to 104°C, a bottom temperature of 175 to 180°C, and a diisobutylene content of >99% at the top of the tower.

[0055] In the above technical solution, in step five, the preferred method for the triisobutylene refining tower is to operate under negative pressure, with a pressure of -1 to -1.5 kPa, a top temperature of 70 to 75°C, a bottom temperature of 110 to 120°C, and a triisobutylene content at the top of the tower > 92%.

[0056] The terminology used in this invention generally has the meanings commonly understood by those skilled in the art, unless otherwise stated. In this invention, atmospheric pressure is 0.1–0.15 MPa.

[0057] To enable those skilled in the art to better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to embodiments.

[0058] In the following embodiments, various processes and methods not described in detail are conventional methods known in the art. Unless otherwise specified, the materials, reagents, apparatus, instruments, equipment, etc., used in the following embodiments are commercially available.

[0059] Example 1

[0060] Step 1: Prepare a metal ion-modified strong acid cation exchange resin;

[0061] 1a) Accurately weigh 6600g of zinc chloride, add it to a 50L plastic bucket, add 6000g of deionized water, stir to dissolve the zinc chloride, and obtain a zinc chloride solution;

[0062] 1b) Weigh 8 kg of strong acid cation exchange resin (diameter ≥ 1.5 mm, water content 52.54%, purchased from Dandong Keli Chemical Technology Co., Ltd. (QSE-05)), pour it into zinc chloride solution within 15-20 s, stir for 5 min, and let it stand for 30 min to obtain ion exchange resin.

[0063] 1c) Remove excess water from the ion exchange resin and wash the ion exchange resin with deionized water until the washing water is free of chloride ions.

[0064] 1d) The washed ion exchange resin was dried at 70°C for 8 hours to obtain a metal ion modified strong acid cation exchange resin.

[0065] Step 2: 2.5 kg of metal ion modified strong acid cation exchange resin is loaded into polymerization reactor 1, and 500 g of metal ion modified strong acid cation exchange resin is loaded into catalytic distillation tower 2.

[0066] Step 3: Fresh isobutylene feedstock supplied via the first pipeline 5, a portion of the reaction product output from polymerization reactor 1 supplied via the second pipeline 6, and a portion of unreacted isobutylene output from catalytic distillation tower 2 supplied via the fifth pipeline 9 are fed into polymerization reactor 1 for polymerization reaction. The resulting reaction product is divided into two parts. One part (80%) is fed into the first pipeline 5 via the second pipeline 6, mixed with fresh isobutylene feedstock and 50% of unreacted isobutylene output from catalytic distillation tower 2, and then fed into polymerization reactor 1. The other part (20%) is fed into catalytic distillation tower 2.

[0067] Step 4: The reaction products in the catalytic distillation tower 2 continue to undergo polymerization. The resulting reaction products are transported to the diisobutylene purification tower 3 via the sixth pipeline 10. A portion (50%) of the unreacted isobutylene is refluxed back to the catalytic distillation tower 2 via the fourth pipeline 8, and the other portion (50%) is transported to the first pipeline 5 via the fifth pipeline 9. It is then mixed with fresh isobutylene raw material and a portion (80%) of the reaction products output from the polymerization reactor 1 before entering the polymerization reactor 1.

[0068] Step 5: The diisobutylene refining tower 3 refines the reaction product and obtains diisobutylene at the top of the tower, which is output through the seventh pipeline 11. The material at the bottom of the tower is transported to the triisobutylene refining tower 4 through the eighth pipeline 12.

[0069] Step 6: Triisobutylene refining tower 4 refines the bottom material and obtains triisobutylene at the top of the tower, which is output through the ninth pipeline 13. The bottom material (heavy component) is discharged through the tenth pipeline 14.

[0070] The temperature, pressure, composition, etc. of each material involved in Example 1 are shown in Table 1.

[0071] Table 1 shows the temperature, pressure, composition, etc. of each material involved in Example 1.

[0072]

[0073]

[0074] In Table 1, DIB-1 represents 2,4,4-trimethyl-1-pentene, DIB-2 represents 2,4,4-trimethyl-2-pentene, TIB-1 represents 2-neopentyl-4,4-dimethyl-1-pentene, and TIB-2 represents 2,2,4,6,6-pentamethyl-3-heptene.

[0075] As shown in Table 1, without the addition of inhibitors, the total conversion rate of isobutylene was 79.42%, and the yields of diisobutylene and triisobutylene were 88.56% and 11.69%, respectively. This indicates that the method of the present invention for producing diisobutylene and triisobutylene has a short process and high separation efficiency.

[0076] Obviously, the above embodiments are merely examples for clear illustration and are not intended to limit the embodiments. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for producing diisobutylene and triisobutylene based on isobutylene, characterized in that, The steps are as follows: Step 1: Place the metal ion-modified strong acid cation exchange resin into the polymerization reactor (1) and the catalyst distillation column (2); Step 2: Fresh isobutylene raw material, a portion of the reaction product output from polymerization reactor (1) and a portion of unreacted isobutylene output from catalytic distillation column (2) are fed into polymerization reactor (1) for polymerization reaction. The mass of fresh isobutylene raw material accounts for 15-22%, the mass of the reaction product output from polymerization reactor (1) accounts for 75-80%, and the mass of unreacted isobutylene output from catalytic distillation column (2) accounts for 3-5%. The resulting reaction product is divided into two parts. One part is mixed with fresh isobutylene raw material and a portion of unreacted isobutylene output from catalytic distillation column (2) and then fed into polymerization reactor (1). The other part is fed into catalytic distillation column (2). Step 3: The reaction products entering the catalytic distillation tower (2) continue to undergo polymerization in the catalytic distillation tower (2). The resulting reaction products are transported to the diisobutylene purification tower (3). Part of the unreacted isobutylene is returned to the catalytic distillation tower (2), and the other part is mixed with fresh isobutylene raw material and part of the reaction products output from the polymerization reactor (1) before entering the polymerization reactor (1). Step 4: The diisobutylene refining tower (3) refines the incoming reaction product, obtaining diisobutylene at the top of the tower and the bottom material is transported to the triisobutylene refining tower (4). Step 5: Triisobutylene refining tower (4) refines the bottom material of the tower to obtain triisobutylene at the top of the tower; In step one, the preparation method of the metal ion-modified strong acid cation exchange resin is as follows: 1a) Dissolve the metal salt in deionized water to obtain a metal salt solution; 1b) Mix the strong acid cation exchange resin with the metal salt solution evenly, let stand to obtain the ion exchange resin, drain the water, wash until there are no metal salt anions, dry to obtain the metal ion modified strong acid cation exchange resin. The metal salt is a nitrate, sulfate, or chloride, and the metal is nickel, copper, or zinc; the strong acid cation exchange resin has a particle size ≥1.5 mm and a water content of 50-55%. The molar ratio of the metal ions of the metal salt to the sulfonic acid groups of the strong acid cation exchange resin is 10-15:

50.

2. The method for producing diisobutylene and triisobutylene based on isobutylene according to claim 1, characterized in that, In step 1b), The settling time is 30–40 minutes; The drying temperature is 60-70℃, and the drying time is 8-12 hours.

3. The method for producing diisobutylene and triisobutylene based on isobutylene according to claim 1, characterized in that, In step two, the inlet temperature of the polymerization reactor (1) is 55-60°C, the outlet temperature is 75-80°C, the reaction pressure is 1-1.2 MPa, and the isobutylene conversion rate is 50-55%.

4. The method for producing diisobutylene and triisobutylene based on isobutylene according to claim 1, characterized in that, In step two, 75-80% of the reaction products are mixed with fresh isobutylene raw materials and a portion of the unreacted isobutylene output from the catalytic distillation tower (2) before entering the polymerization reactor (1), and 20-25% of the reaction products enter the catalytic distillation tower (2). In step three, 50-60% of the unreacted isobutylene is refluxed to the catalytic distillation column (2), and 40-50% of the unreacted isobutylene is mixed with fresh isobutylene raw material and a portion of the reaction product output from the polymerization reactor (1) before entering the polymerization reactor (1).

5. The method for producing diisobutylene and triisobutylene based on isobutylene according to claim 1, characterized in that, In step three, the pressure of the catalytic distillation column (2) is 0.45-0.5 MPa, the temperature at the top of the column is 42-45°C, the temperature at the bottom of the column is 130-135°C, and the reflux ratio at the top of the column is 1-1.5:

1.

6. The method for producing diisobutylene and triisobutylene based on isobutylene according to claim 1, characterized in that, In step three, a cylindrical catalyst loading container is fixed inside the catalytic distillation column (2) for loading a strong acid cation exchange resin modified with metal ions. The outer diameter of the catalyst loading container is fitted with the inner diameter of the catalytic distillation column (2) with a clearance. The height of the catalyst loading container is 1.5 to 2 times its outer diameter. The catalyst loading container has through holes with a diameter of 0.5 to 1.5 mm evenly distributed on it. The lower surface of the catalyst loading container is located in the middle of the catalytic distillation column (2). The catalyst loading container is made of stainless steel.

7. The method for producing diisobutylene and triisobutylene based on isobutylene according to claim 1, characterized in that, In step four, the diisobutylene refining tower (3) is operated under normal pressure or slightly positive pressure, with a pressure of 0.1 to 0.15 MPa, a top temperature of 102 to 104°C, a bottom temperature of 175 to 180°C, and a diisobutylene content of >99% at the top of the tower.

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