A fluorine-containing phosphonic acid type weak acidic cation resin catalyst and a preparation method thereof, and a preparation method of tert-butyl (meth)acrylate

Abstract

The application provides a preparation method of a fluorine-containing phosphonic acid type weak acid cation resin catalyst and a preparation method of a (methyl) butyl acrylate, the fluorine-containing phosphonic acid type weak acid cation resin catalyst is a solid catalyst capable of catalyzing acid-olefin addition reaction of (methyl) acrylate and isobutene, the swelling rate in an isobutene system is low, the selectivity of by-products diisobutene and triisobutene is low when the catalyst is used in the preparation of the (methyl) butyl acrylate, and the continuous production operation of the (methyl) butyl acrylate can be realized, and the product reaction selectivity is high.

Description

Technical Field

[0001] This invention belongs to the field of organic compound preparation, specifically relating to a fluorinated phosphonic acid type weak acidic cationic resin catalyst and its preparation method, and a method for preparing tert-butyl methacrylate. Background Technology

[0002] Tert-butyl methacrylate (TMB)A is an important organic synthesis raw material widely used in coatings, inks, adhesives, plastics, resins, and other fields, with broad application prospects and market demand.

[0003] Currently, the main method for industrial production of tert-butyl methacrylate is to synthesize it by reacting (meth)acrylic acid and isobutylene under acidic catalytic conditions.

[0004] Patent CN202210076468.3 discloses a method for synthesizing tert-butyl (meth)acrylate, which involves reacting (meth)acrylate with isobutylene in the presence of a polymerization inhibitor and a catalyst to prepare tert-butyl (meth)acrylate. The catalyst used is a macroporous, strongly acidic cation exchange resin polymerized primarily from styrene and divinylbenzene. However, this method exhibits high selectivity for the byproducts diisobutylene and triisobutylene, while the selectivity for the product tert-butyl acrylate is low, at only 94.9%.

[0005] Patent CN202211477485.4 discloses a process for preparing tert-butyl methacrylate, which involves adding (meth)acrylic acid, a catalyst, a polymerization inhibitor, isobutylene, and an inert substance into a reaction vessel to synthesize tert-butyl methacrylate. The catalyst is one or more of acidic cationic resin, p-toluenesulfonic acid, and Nafion. However, this method uses a batch reaction process, and the selectivity of tert-butyl acrylate is only 98.6%, resulting in a low yield.

[0006] Patent CN201310041364.X discloses a process for the catalytic synthesis of tert-butyl acrylate using a strongly acidic cation exchange resin as a catalyst. Acrylic acid, a strongly acidic cation exchange resin, polymerization inhibitor A, and polymerization inhibitor B are added to a closed reactor. Liquefied isobutylene is added dropwise to initiate an esterification reaction. After the addition is complete, the reactor is kept at a constant temperature. After the temperature is maintained, the closed reactor is depressurized, filtered, and the liquid components are drawn into a distillation column. The byproducts tert-butanol and diisobutylene, and the target product tert-butyl acrylate, are separated sequentially. This example uses a batch reaction process.

[0007] Patent CN201911266958.4 discloses a process for synthesizing tert-butyl acrylate, using acrylic acid and isobutylene as raw materials and p-toluenesulfonic acid as a catalyst. The process involves an acid-olefin addition reaction in a microchannel reactor, and the reaction solution is separated to obtain tert-butyl acrylate. This process utilizes a microchannel reactor, which is suitable for the strongly exothermic acid-olefin addition reaction, improving the reaction conversion rate and product selectivity. However, the selectivity of tert-butyl acrylate still needs further improvement.

[0008] Due to the high selectivity of diisobutylene and triisobutylene byproducts in the traditional direct olefin addition reaction of (meth)acrylic acid and isobutylene to prepare tert-butyl methacrylate, but low product selectivity, there is an urgent need to develop new catalysts and preparation methods for tert-butyl methacrylate to achieve high product selectivity and continuous and stable operation. Summary of the Invention

[0009] To address the aforementioned problems, this invention provides a fluorinated phosphonic acid type weakly acidic cationic resin catalyst and its preparation method, as well as a method for preparing tert-butyl methacrylate. The fluorinated phosphonic acid type weakly acidic cationic resin catalyst of this invention can be used to catalyze the acid-olefin addition reaction of (meth)acrylic acid and isobutylene. It exhibits low swelling ratio in the isobutylene system. When used in the preparation of tert-butyl methacrylate, the selectivity for byproducts diisobutylene and triisobutylene is low, enabling continuous production of tert-butyl methacrylate with high product selectivity.

[0010] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows:

[0011] This invention provides a fluorinated phosphonic acid type weakly acidic cationic resin catalyst having at least one of the following structural formulas:

[0012]

[0013] The values ​​of m and n are independently 5 to 50, preferably 10 to 40;

[0014] In this invention, the fluorinated phosphonic acid type weakly acidic cation exchange resin catalyst preferably has the following structure.

[0015]

[0016] In this invention, the number average molecular weight of the fluorinated phosphonic acid type weak acidic cation exchange resin catalyst is 5000-7000.

[0017] In this invention, the fluorine content in the fluorinated phosphonic acid type weak acidic cation exchange resin catalyst is 40-50 wt%.

[0018] In this invention, the phosphorus content of the fluorinated phosphonic acid type weak acidic cation exchange resin catalyst is 6-12 wt%.

[0019] The present invention also provides a method for preparing the above-mentioned fluorinated phosphonic acid type weakly acidic cation exchange resin catalyst, comprising the following steps:

[0020] (1) Polymerization reaction of p-chlorostyrene and perfluoroolefins to prepare copolymer white spheres;

[0021] (2) Add alkyl phosphite to the copolymer white spheres obtained in step (1) to carry out phosphonylation reaction to obtain phosphonylated product;

[0022] (3) The phosphonylation product obtained in step (2) is hydrolyzed in phosphoric acid to obtain a fluorinated phosphonic acid type weak acidic cationic resin catalyst.

[0023] The styrene units and perfluoroolefin units in the catalyst are random copolymers.

[0024] In step (1) of this invention, the polymerization reaction is carried out at a temperature of 60-130°C, preferably 85-105°C, for a time of 3-14 hours, preferably 8-9 hours, and at a pressure of 2-7 MPaG, preferably 3-4 MPaG. After the reaction is completed, the pressure is released to atmospheric pressure.

[0025] The molar ratio of the perfluoroolefin to p-chlorostyrene is 1 to 4:1, preferably 2 to 3:1.

[0026] The perfluoroolefin is at least one of tetrafluoroethylene and / or hexafluoropropylene, preferably tetrafluoroethylene.

[0027] In step (1), an initiator is also added, which is selected from peroxide or azo initiators.

[0028] Preferably, the polymerization reaction further includes post-processing steps such as preparing oil beads. Known techniques in the art can be used, such as adding pure water and a gelatin-methylene blue solution to a reaction vessel, heating to 60-100°C, then adding the oil phase obtained after the polymerization reaction and reacting for 4-12 hours. After cooling and filtration, beads are obtained, and after washing and drying, copolymer white beads are obtained.

[0029] In step (2) of the present invention, the phosphonylation reaction is carried out at a temperature of 130-180°C, preferably 150-170°C, for a time of 5-15 hours, preferably 8-10 hours.

[0030] In the phosphonylation reaction, the alkyl phosphite is at least one selected from trimethyl phosphite, triethyl phosphite, and tributyl phosphite, preferably triethyl phosphite.

[0031] In the phosphonylation reaction, the mass ratio of the alkyl phosphite to the copolymer white spheres is 1–8:1, preferably 4–5:1.

[0032] The solvent for the phosphonylation reaction is at least one of propylene glycol methyl ether acetate, N,N-dimethylacetamide, and ethylene glycol monotert-butyl ether, preferably N,N-dimethylacetamide.

[0033] In the phosphonylation reaction, the mass ratio of solvent to copolymer white spheres is 1 to 7:1, preferably 3 to 4:1.

[0034] Preferably, the process further includes post-treatment steps such as washing and filtration after the phosphonylation reaction is completed.

[0035] In step (3) of this invention, the hydrolysis reaction temperature is 50-110℃, preferably 70-90℃, and the time is 4-16h, preferably 8-12h.

[0036] In step (3), the phosphoric acid is preferably concentrated phosphoric acid with a concentration of 80-85 wt%.

[0037] In step (3), the mass ratio of concentrated phosphoric acid to phosphonylation product is 2 to 7:1, preferably 4 to 5:1.

[0038] Preferably, after the hydrolysis reaction is completed, the process further includes post-treatment processes such as washing, filtering, and drying.

[0039] The present invention also provides a method for preparing tert-butyl (meth)acrylate, wherein (meth)acrylate and isobutylene undergo an acid-olefin addition reaction under the conditions of a fluorinated phosphonic acid type weak acidic cationic resin catalyst as described in the present invention.

[0040] In this invention, a segmented fixed-bed tubular reactor is used, with isobutylene fed in segments.

[0041] This invention employs a segmented fixed-bed tubular reactor, preferably a fixed-bed tubular reactor with three or more segments, and more preferably a fixed-bed tubular reactor with three segments: upper, middle, and lower. Isobutylene is fed from the upper, middle, and lower segments respectively, which can further reduce the generation of by-products diisobutylene and triisobutylene, and reduce the consumption of isobutylene.

[0042] In this invention, the concentration of isobutylene in the fixed-bed tubular reactor can be controlled by controlling the segmented feeding method, so that the concentration of isobutylene inside the fixed-bed tubular reactor is low, avoiding the selective increase of by-product diisobutylene and triisobutylene due to excessively high isobutylene concentration.

[0043] In this invention, the reactor is filled with a fluorinated phosphonic acid type weak acidic cationic resin catalyst.

[0044] In this invention, in order to better achieve a uniform distribution of the reaction heat in the segmented fixed-bed tubular reactor, warm water is used for heat exchange. The temperature of the warm water is 20-40°C, preferably 25-35°C.

[0045] In this invention, a polymerization inhibitor is also added to the reaction, wherein the polymerization inhibitor is at least one of ZJ-701, ZJ-705, ZJ-706 and ZJ-709, preferably ZJ-706;

[0046] In this invention, the mass ratio of the polymerization inhibitor to (meth)acrylic acid is 0.0001 to 0.005:1, preferably 0.001 to 0.002:1.

[0047] In this invention, the molar ratio of isobutylene to (meth)acrylic acid is 1.0 to 2:1, preferably 1.1 to 1.2:1.

[0048] In this invention, the feed volume space velocity of the mixture is 0.3 to 3 h⁻¹. -1 Preferably 0.8–1.5 h -1 The reaction hotspot temperature is 20–50°C, preferably 30–40°C; the reaction pressure is 0.4–1.0 MPaG, preferably 0.6–0.7 MPaG.

[0049] In this invention, compressed nitrogen needs to be continuously introduced during the reaction process to maintain the pressure of the reaction system; preferably, the maximum pressure of the compressed nitrogen required to replenish the system pressure is 0.4 to 1.0 MPaG, more preferably 0.6 to 0.7 MPaG.

[0050] The beneficial effects of the technical solution of this invention are as follows:

[0051] The fluorinated phosphonic acid type weak acidic cation exchange resin catalyst has moderate catalyst activity, selectively catalyzes the main reaction, and produces byproducts diisobutylene and triisobutylene with low selectivity. The reaction conditions are mild and the production is continuous. The selectivity of (methyl)tert-butyl ester is as high as 99% or more, and the conversion rate of (meth)acrylic acid is as high as 99.9%.

[0052] The fluorinated phosphonic acid type weak acidic cationic resin catalyst used contains fluorine, which has good resistance to swelling in the reaction liquid containing isobutylene, high strength, and is not easily crushed or pulverized under high pressure, thus extending the service life of the catalyst.

[0053] A segmented fixed-bed tubular reactor is adopted, with isobutylene fed in stages, ensuring uniform isobutylene concentration within the reactor and avoiding increased selectivity of by-products caused by high local isobutylene concentration.

[0054] The entire process is highly atom-economical, produces no catalyst waste liquid, generates little waste, and is environmentally friendly. It can be used for the large-scale continuous production of tert-butyl methacrylate. Detailed Implementation

[0055] The present invention will be further illustrated below by way of embodiments, but the present invention is not limited to the embodiments described below. The present invention extends to any new feature or any new combination disclosed in the specification, as well as any new method or process step or any new combination disclosed.

[0056] I. Sources of main raw materials in the embodiments:

[0057] 1. Chlorostyrene, Hubei Xingyan New Material Technology Co., Ltd., analytical grade;

[0058] 2. Hexafluoropropylene, Dalian Date Gas Co., Ltd., analytical grade;

[0059] 3. Tetrafluoroethylene, Dalian Date Gas Co., Ltd., analytical grade;

[0060] 4. Triethyl phosphite, Handan Xinyuansheng Chemical Co., Ltd., Congtai District, Handan City, analytical grade;

[0061] 5. N,N-Dimethylacetamide, Beijing Innocare Technology Co., Ltd., analytical grade;

[0062] 6. 85% concentrated phosphoric acid, Beijing Innocare Technology Co., Ltd., analytical grade;

[0063] 7. Acrylic acid, Wanhua Chemical Group Co., Ltd., industrial grade;

[0064] 8. Methacrylic acid, Wanhua Chemical Group Co., Ltd., industrial grade;

[0065] 9. Isobutylene, Dalian Date Gas Co., Ltd., analytical grade;

[0066] 10. 706 polymerization inhibitor, Jiangsu Bost Chemical Technology Co., Ltd., industrial grade;

[0067] II. Product Analysis Methods in the Examples:

[0068] Determination of catalyst molecular weight using gel permeation chromatography (GPC); Instrument manufacturer and model: Shimadzu (Japan) LC-20AD;

[0069] Determination of BET value of catalyst using physical adsorption instrument; Instrument manufacturer and model: MICROMERITICS (USA) ASAP2020;

[0070] Gas chromatography analysis used the correction factor method. Instrument manufacturer and model: Shimadzu 1020-plus.

[0071] X-ray fluorescence spectrometry (XRF) was used to determine the fluorine content of catalysts. Instrument manufacturer and model: PANalytical (Netherlands) Axios mAX;

[0072] Example 1:

[0073] The steps for preparing a fluorinated phosphonic acid-type weakly acidic cation exchange resin catalyst are as follows:

[0074] (1) Add tetrafluoroethylene (8 kg) and p-chlorostyrene (5.54 kg) in a 2:1 (mol) ratio to a 50 L mixing vessel and mix well. Add 81.24 g of 0.6 wt% tert-butyl hydrogen peroxide (based on total amount) and heat to 85 °C. At the same time, purge with nitrogen to control the reaction pressure to 3 MPaG to prepare the oil phase. Add 16 kg of pure water, 0.8 kg of gelatin and 0.04 kg of appropriate amount of methylene blue solution to the reaction vessel. Heat to 85 °C and add oil phase dropwise for 8 h. Cool to 20 °C and filter to obtain beads. Wash with 72 kg of dichloromethane, filter and dry to obtain copolymer white spheres.

[0075] (2) Mix 6 kg of N,N-dimethylacetamide with 2 kg of the copolymer white balls obtained in step 1) at a ratio of 3:1 (mass ratio), heat to 150°C, add 8 kg of triethyl phosphite dropwise over a period of 4 h, continue aging for 4 h after the addition is complete, cool to 20°C and filter to obtain beads, wash with 10 kg of dichloromethane, filter and dry to obtain phosphonylated product.

[0076] (3) Mix 8 kg of 85 wt% concentrated phosphoric acid with the phosphonylated product obtained in step 2) at a ratio of 4:1 (mass ratio), heat to 70°C, continue the reaction for 8 h, cool to 20°C, filter, wash with 10 kg of dichloromethane, filter and dry to obtain a fluorinated phosphonic acid type weak acidic cationic resin catalyst.

[0077] The fluorinated phosphonic acid type weak acidic cation exchange resin catalyst prepared in Example 1 has a molecular weight of approximately 5610 (Mn), a fluorine content of 40.6%, a phosphorus content of 8.3%, and a swelling rate of 3.3% in isobutylene.

[0078] Example 2:

[0079] The steps for preparing a fluorinated phosphonic acid-type weakly acidic cation exchange resin catalyst are as follows:

[0080] (1) Add tetrafluoroethylene (6 kg) and p-chlorostyrene (2.77 kg) in a 2:1 (mol) ratio to a 50 L mixing vessel and mix well. Add 52.62 g of 0.6 wt% tert-butyl hydrogen peroxide (based on total amount) and heat to 105 °C. At the same time, purge with nitrogen to control the reaction pressure to 4 MPaG to prepare the oil phase. Add 12 kg of pure water, 0.6 kg of gelatin and 0.03 kg of methylene blue solution to the reaction vessel. Heat to 105 °C and add oil phase dropwise for 9 h. Cool to 20 °C and filter to obtain beads. Wash with 54 kg of dichloromethane, filter and dry to obtain copolymer white beads.

[0081] (2) Mix 8 kg of N,N-dimethylacetamide with the copolymer white balls obtained in step 1) at a ratio of 4:1 (mass ratio), heat to 170°C, add 10 kg of triethyl phosphite dropwise over a period of 4 h, continue aging for 4 h after the addition is complete, cool to 20°C and filter to obtain beads, wash with 10 kg of dichloromethane, filter and dry to obtain phosphonylated product.

[0082] (3) Mix 10 kg of 85 wt% concentrated phosphoric acid with the phosphonylated product obtained in step 2) at a ratio of 5:1 (mass ratio), heat to 90 °C, continue to react for 12 h, cool to 20 °C, filter, wash with 10 kg of dichloromethane, filter and dry to obtain a fluorinated phosphonic acid type weak acidic cationic resin catalyst.

[0083] The fluorinated phosphonic acid type weak acidic cation exchange resin catalyst prepared in Example 2 has a molecular weight of approximately 6889 (Mn), a fluorine content of 48.1%, a phosphorus content of 6.5%, and a swelling rate of 2.9% in isobutylene.

[0084] Examples 3-7

[0085] The fluorinated phosphonic acid type weakly acidic cationic resin catalyst prepared in Example 1 was loaded into a jacketed three-stage fixed-bed tubular reactor. First, 706 polymerization inhibitor was added to acrylic acid to prepare an acrylic acid solution. Isobutylene and acrylic acid solution were added to the fixed-bed reactor in a certain ratio. The isobutylene was divided into three parts and fed into the upper, middle and lower feed ports of the reactor, respectively. The reaction pressure was controlled to 0.6 MPaG by adding oxygen-deficient gas. The reaction hot spot temperature was controlled to 30°C by adjusting the temperature of the jacket water. The ratio of isobutylene to acrylic acid in the raw material mixture was changed. The specific reaction process conditions and reaction results of Examples 3 to 7 are detailed in Table 1.

[0086] Table 1

[0087]

[0088]

[0089] Example 3: After 2000 hours of stable operation, the acrylic acid conversion rate remained stable at 99.0% or higher, the selectivity of tert-butyl acrylate remained above 99.0%, and the sum of the selectivities of the by-products diisobutylene and triisobutylene was less than 1%.

[0090] Examples 8-10

[0091] The fluorinated phosphonic acid type weakly acidic cationic resin catalyst prepared in Example 2 was loaded into a jacketed three-stage fixed-bed tubular reactor. First, 706 polymerization inhibitor was added to acrylic acid to prepare an acrylic acid solution. Isobutylene and acrylic acid solution were added to the fixed-bed reactor in a certain ratio. The isobutylene was divided into three parts and fed into the upper, middle and lower feed ports of the reactor, respectively. The reaction pressure was controlled at 0.7 MPaG by adding oxygen-deficient gas. The reaction hot spot temperature was controlled at 50°C by adjusting the temperature of the jacket water. The ratio of isobutylene to acrylic acid in the raw material mixture was changed. The specific reaction process conditions and reaction results of Examples 8 to 10 are detailed in Table 2.

[0092] Table 2

[0093]

[0094] Example 8: After 3000 hours of stable operation, the acrylic acid conversion rate remained stable at 99.0% or higher, the selectivity of tert-butyl acrylate remained above 99.0%, and the sum of the selectivities of the by-products diisobutylene and triisobutylene was less than 1%.

[0095] Example 11

[0096] The fluorinated phosphonic acid type weakly acidic cationic resin catalyst prepared in Example 2 was loaded into a jacketed three-stage fixed-bed tubular reactor. First, 706 polymerization inhibitor was added to methacrylic acid to prepare a methacrylic acid solution. Isobutylene and the methacrylic acid solution were added to the fixed-bed reactor in a certain proportion. The isobutylene was divided into three parts and fed into the upper, middle and lower feed ports of the reactor, respectively. The reaction pressure was controlled at 0.7 MPaG by adding oxygen-deficient gas. The reaction hot spot temperature was controlled at 50°C by adjusting the temperature of the jacket water. The ratio of isobutylene to acrylic acid in the raw material mixture was changed. The specific reaction process conditions and reaction results of Examples 13 to 17 are detailed in Table 3.

[0097] Table 3

[0098]

[0099] Example 11: After 2000 hours of stable operation, the conversion rate of methacrylic acid remained stable at 98.0% or higher, the selectivity of tert-butyl methacrylate was maintained at 99.0% or higher, and the sum of the selectivities of the by-products diisobutylene and triisobutylene was less than 1%.

[0100] As can be seen from the data in Tables 1, 2 and 3 above, by filling with a fluorinated phosphonic acid type weak acidic cationic resin catalyst, under optimal reaction process conditions, the conversion rate of (meth)acrylic acid can reach over 98%, the selectivity of tert-butyl (meth)acrylic acid can reach over 99.0%, and no catalyst blockage was found in the reactor after more than 2000 hours of operation.

[0101] Example 12

[0102] The difference from Example 3 is that the fixed-bed reactor adopts a non-segmented design with a single isobutylene feed point. After stabilizing under the same conditions, the acrylic acid conversion rate is 99.09%, but the selectivity of tert-butyl acrylate is 96.8%, and the combined selectivity of by-product diisobutylene and triisobutylene is 3.2%.

[0103] Comparative Example 1

[0104] The difference from Example 3 is that a commercially available strong acid cation exchange resin (brand name A36, Dow Chemical (Shanghai) Co., Ltd.) was used. After stabilization under the same conditions, the acrylic acid conversion rate was 99.0%, but the selectivity of tert-butyl acrylate was 92.1%, and the combined selectivity of by-product diisobutylene and triisobutylene was 7.9%, which affected the product yield.

Claims

1. A fluorinated phosphonic acid type weakly acidic cationic resin catalyst, characterized in that, It has at least one of the following structural formulas: or ; The values ​​of m and n are independently 5 to 50.

2. The catalyst according to claim 1, characterized in that, The values ​​of m and n are independently 10 to 40.

3. The catalyst according to claim 1, characterized in that, The structure of the catalyst is as follows: ， The meanings of m and n are the same as in claim 1.

4. The catalyst according to claim 1 or 2, characterized in that, The number average molecular weight of the fluorinated phosphonic acid type weak acidic cation exchange resin catalyst is 5000-7000.

5. The catalyst according to claim 1 or 2, characterized in that, The fluorine content in the fluorinated phosphonic acid type weak acidic cation exchange resin catalyst is 40-50 wt%.

6. The catalyst according to claim 1 or 2, characterized in that, The phosphorus content of the fluorinated phosphonic acid type weak acidic cation exchange resin catalyst is 6-12 wt%.

7. The method for preparing the catalyst according to claim 1, characterized in that, Includes the following steps: (1) Polymerize p-chlorostyrene and perfluoroolefins to prepare copolymer white spheres; (2) Add alkyl phosphite to the copolymer white spheres obtained in step (1) to carry out phosphonylation reaction to obtain phosphonylated product; (3) The phosphonylation product obtained in step (2) is hydrolyzed in phosphoric acid to obtain a fluorinated phosphonic acid type weak acidic cationic resin catalyst.

8. The preparation method according to claim 7, characterized in that, In step (1), the polymerization reaction temperature is 60℃~130℃, the reaction time is 3~14h, the reaction pressure is 2~7MPaG, and the pressure is released to atmospheric pressure after the reaction is completed.

9. The preparation method according to claim 8, characterized in that, In step (1), the polymerization reaction temperature is 85℃~105℃, the reaction time is 8~9h, the reaction pressure is 3~4MPaG, and the pressure is released to atmospheric pressure after the reaction is completed.

10. The preparation method according to claim 7, characterized in that, In step (1), the molar ratio of the perfluoroolefin and p-chlorostyrene is 1 to 4:

1.

11. The preparation method according to claim 10, characterized in that, In step (1), the molar ratio of the perfluoroolefin to p-chlorostyrene is 2 to 3:

1.

12. The preparation method according to claim 7, characterized in that, The perfluoroolefin is at least one of tetrafluoroethylene or hexafluoropropylene.

13. The preparation method according to claim 12, characterized in that, The perfluoroolefin is tetrafluoroethylene.

14. The preparation method according to claim 7, characterized in that, In step (1), an initiator is also added. The initiator is selected from peroxide or azo initiators.

15. The preparation method according to claim 7, characterized in that, In step (2), the phosphonylation reaction temperature is 130-180℃ and the time is 5-15h.

16. The preparation method according to claim 15, characterized in that, In step (2), the phosphonylation reaction temperature is 150-170℃ and the time is 8-10h.

17. The preparation method according to claim 7, characterized in that, The alkyl phosphite is at least one of trimethyl phosphite, triethyl phosphite, and tributyl phosphite.

18. The preparation method according to claim 17, characterized in that, The alkyl phosphite is triethyl phosphite.

19. The preparation method according to claim 7, characterized in that, The mass ratio of the alkyl phosphite to the copolymer white spheres is 1 to 8:

1.

20. The preparation method according to claim 19, characterized in that, The mass ratio of the alkyl phosphite to the copolymer white spheres is 4–5:

1.

21. The preparation method according to claim 7, characterized in that, The phosphonylation reaction is carried out in a solvent, which is at least one of propylene glycol methyl ether acetate, N,N-dimethylacetamide, and ethylene glycol monotert-butyl ether.

22. The preparation method according to claim 21, characterized in that, The solvent is N,N-dimethylacetamide.

23. The preparation method according to claim 21, characterized in that, In the phosphonylation reaction, the mass ratio of solvent to copolymer white spheres is 1 to 7:

1.

24. The preparation method according to claim 23, characterized in that, In the phosphonylation reaction, the mass ratio of solvent to copolymer white spheres is 3 to 4:

1.

25. The preparation method according to claim 7, characterized in that, In step (3), the hydrolysis reaction temperature is 50-110℃ and the time is 4-16h.

26. The preparation method according to claim 25, characterized in that, In step (3), the hydrolysis reaction temperature is 70-90℃ and the time is 8-12h.

27. The preparation method according to claim 7, characterized in that, In step (3), the concentration of phosphoric acid is 80-85 wt% concentrated phosphoric acid.

28. The preparation method according to claim 7, characterized in that, In step (3), the mass ratio of phosphoric acid to phosphonylation product is 2 to 7:

1.

29. The preparation method according to claim 28, characterized in that, In step (3), the mass ratio of phosphoric acid to phosphonylation product is 4 to 5:

1.

30. A method for preparing tert-butyl methacrylate, wherein (meth)acrylic acid and isobutylene undergo an acid-olefin addition reaction in the presence of a catalyst as described in any one of claims 1-3 or a catalyst prepared by any one of claims 7-29.

31. The preparation method according to claim 30, characterized in that, The reactor is a segmented fixed-bed tubular reactor with segmented feeding of isobutylene.

32. The preparation method according to claim 31, characterized in that, The reactor is a fixed-bed tubular reactor with three or more sections.

33. The preparation method according to claim 32, characterized in that, The reactor is a three-stage fixed-bed tubular reactor, with isobutylene fed from the upper, middle, and lower stages respectively.

34. The preparation method according to claim 30, characterized in that, The reaction also includes a polymerization inhibitor, which is at least one of ZJ-701, ZJ-705, and ZJ-706.

35. The preparation method according to claim 34, characterized in that, The polymerization inhibitor is ZJ-706.

36. The preparation method according to claim 34, characterized in that, The mass ratio of the polymerization inhibitor to (meth)acrylic acid is 0.0001 to 0.005:

1.

37. The preparation method according to claim 36, characterized in that, The mass ratio of the polymerization inhibitor to (meth)acrylic acid is 0.001 to 0.002:

1.

38. The preparation method according to claim 30, characterized in that, The molar ratio of isobutylene to (meth)acrylic acid is 1.0 to 2:

1.

39. The preparation method according to claim 38, characterized in that, The molar ratio of isobutylene to (meth)acrylic acid is 1.1 to 1.2:

1.

40. The preparation method according to claim 30, characterized in that, The feed volumetric space velocity of the mixture is 0.3–3 h⁻¹. -1 .

41. The preparation method according to claim 40, characterized in that, The feed volumetric space velocity of the mixture is 0.8–1.5 h⁻¹. -1 .

42. The preparation method according to claim 40, characterized in that, The hot spot temperature of the reaction is 20–50℃; the reaction pressure is 0.4–1.0 MPaG.

43. The preparation method according to claim 42, characterized in that, The hot spot temperature of the reaction is 30-40℃; the reaction pressure is 0.6-0.7 MPaG.

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