Perfluorosulfonic acid resin catalyst and preparation method thereof

Abstract

The invention provides a perfluorinated sulfonic acid resin catalyst and a preparation method thereof. The preparation method comprises the following steps: S1, granulating acyl fluoride type perfluorinated sulfonic acid resin to obtain a first intermediate product; s2, carrying out end group stabilizing treatment on the first intermediate product to obtain a second intermediate product; s3, granulating the second intermediate product to obtain a third intermediate product; s4, carrying out transformation treatment on the third intermediate product, so that the acyl fluoride type perfluorinated sulfonic acid resin is transformed into H type perfluorinated sulfonic acid resin, and obtaining a fourth intermediate product; s5, removing impurities from the fourth intermediate product by using a solvent, and removing residual additives and oligomers in the fourth intermediate product to obtain a fifth intermediate product; and step S6, drying the fifth intermediate product to obtain the perfluorosulfonic acid resin catalyst.

Description

Technical Field

[0001] This invention relates to solid protic acid perfluorosulfonic acid resin catalysts for organic and polymerization reactions. Specifically, it relates to a particulate perfluorosulfonic acid resin catalyst and its preparation method. The particulate perfluorosulfonic acid catalyst prepared using the method of this invention exhibits higher single-pass conversion, better product appearance, and longer catalytic life. This particulate perfluorosulfonic acid resin catalyst can be used in organic reactions such as alkylation, halogenation, isomerization, and esterification, as well as oligomerization and cationic polymerization reactions. Background Technology

[0002] Perfluorosulfonic acid (PFSA) proton exchange membranes were first developed and commercially produced by DuPont in the 1970s (Nafion). ® The perfluorosulfonic acid (PFSA) proton exchange membrane (PFSA) comprises a polytetrafluoroethylene-like main chain and short side chains containing sulfonic acid groups. This structural feature gives PFSA proton exchange membranes both high stability and high proton conductivity. Currently, perfluorosulfonic acid resins are mainly used in the production of proton exchange membranes, and they are widely used as fuel cell membranes, chlor-alkali industrial electrolysis experimental membranes, and solid polymer electrolytes.

[0003] Furthermore, perfluorosulfonic acid resins, as solid protonic acid catalysts, exhibit excellent catalytic activity in organic synthesis (such as alkylation, acylation, nitration, sulfonation, phosphorylation, polymerization, condensation, etherification, esterification, hydration, and rearrangement reactions). Compared to liquid acid catalysis, perfluorosulfonic acid resins offer advantages such as non-corrosiveness, no waste acid production, easy product separation, high selectivity, and reusability. Compared to general solid acids, they offer advantages such as higher yields, milder reaction conditions, and faster reaction rates. Compared to other acidic cation exchange resins, they exhibit stronger acidity and higher operating temperatures, making them an ideal solid acid catalyst.

[0004] Currently, there are several main methods for preparing sulfonic acid resin catalysts, such as supported methods and solution methods. These methods, to varying degrees, suffer from problems such as long preparation routes, complex processes, low single-pass conversion rates, short catalyst lifetimes, and poor product appearance.

[0005] The information disclosed in this background section is only for enhancing the understanding of the background technology of the present invention, and therefore may include information that does not constitute prior art. Summary of the Invention

[0006] To overcome the numerous problems existing in the preparation methods of sulfonic acid resin catalysts, this invention provides a method for preparing particulate perfluorosulfonic acid resin catalysts. The particulate perfluorosulfonic acid resin catalyst prepared by this method has a higher single-pass conversion rate, better product appearance, and longer catalytic life.

[0007] However, the present invention is not limited to the above aspects, but can be extended in various ways without departing from the technical spirit of the present invention.

[0008] One aspect of the present invention provides a method for preparing a perfluorosulfonic acid resin catalyst, the method comprising the following steps: Step S1: granulating an acyl fluoride type perfluorosulfonic acid resin to obtain a first intermediate product; Step S2: performing end-group stabilization treatment on the first intermediate product to obtain a second intermediate product; Step S3: granulating the second intermediate product to obtain a third intermediate product; Step S4: performing a transformation treatment on the third intermediate product to transform the acyl fluoride type perfluorosulfonic acid resin into an H-type perfluorosulfonic acid resin to obtain a fourth intermediate product; Step S5: removing impurities from the fourth intermediate product using a solvent to remove residual additives and oligomers to obtain a fifth intermediate product; Step S6: drying the fifth intermediate product to obtain the perfluorosulfonic acid resin catalyst.

[0009] According to an embodiment of the present invention, in step S1, the ion exchange equivalent (EW) of the acyl fluoride type perfluorosulfonic acid resin is 1000 g / mol to 1300 g / mol. Step S1 includes: granulating the polymerized, condensed, and dried acyl fluoride type perfluorosulfonic acid resin using an extruder to obtain a granular first intermediate product.

[0010] According to an embodiment of the present invention, step S2 includes: placing a first intermediate product in a reactor, introducing a processing gas, and performing an end-group stabilization treatment for a first predetermined time at a first predetermined pressure and a first predetermined temperature, so that the acyl fluoride end group or carboxyl end group of the first intermediate product is converted into a trifluoromethyl end group, thereby obtaining a second intermediate product. The processing gas is a mixture of fluorine gas and nitrogen gas with a volume ratio of 1:4, the first predetermined pressure is 0.2 MPa to 1 MPa, the first predetermined temperature is 70°C to 150°C, and the first predetermined time is 10 hours to 30 hours.

[0011] According to an embodiment of the present invention, the first predetermined pressure is 0.4 MPa, the first predetermined temperature is 80°C, and the first predetermined time is 18 hours.

[0012] According to an embodiment of the present invention, step S3 includes: granulating the second intermediate product using an extruder to obtain a granular third intermediate product, wherein the particle size of the third intermediate product is smaller than that of the first intermediate product.

[0013] According to an embodiment of the present invention, step S4 includes: treating the third particles with an alkali metal hydroxide solution at a second predetermined pressure and a second predetermined temperature for a second predetermined time, so that the acyl fluoride type perfluorosulfonic acid resin is transformed into an alkali metal ionic type perfluorosulfonic acid resin; then treating the alkali metal ionic type perfluorosulfonic acid resin with a strong acid solution at a third predetermined pressure and a third predetermined temperature for a third predetermined time to obtain a product containing H... + The fourth intermediate product of perfluorosulfonic acid resin.

[0014] According to an embodiment of the present invention, the alkali metal hydroxide solution is a KOH solution or a NaOH solution, the strong acid solution is a 10wt% to 30wt% nitric acid solution, the second predetermined pressure is atmospheric pressure, the second predetermined temperature is 60°C to 100°C, the second predetermined time is 15 hours to 40 hours, the third predetermined pressure is atmospheric pressure, the third predetermined temperature is 60°C to 100°C, and the third predetermined time is 15 hours to 40 hours.

[0015] According to an embodiment of the present invention, step S5 includes: placing the fourth intermediate product in a high-pressure reactor, adding a solvent, and treating it at a second predetermined pressure and a second predetermined temperature for a second predetermined time. The solvent includes at least one of ethanol, acetone, isopropanol, and diethyl ether. The mass ratio of the fourth intermediate product to the solvent is 1:2 to 1:10. The second predetermined pressure is 0.5 MPa to 2 MPa. The second predetermined temperature is 100°C to 200°C. The second predetermined time is 1 hour to 10 hours.

[0016] According to an embodiment of the present invention, the mass ratio of the fourth intermediate product to the solvent is 1:3 to 1:6, the second predetermined pressure is 1 MPa to 1.5 MPa, the second predetermined temperature is 120°C to 160°C, and the second predetermined time is 2 hours to 5 hours.

[0017] Another aspect of the present invention provides a perfluorosulfonic acid resin catalyst, which is prepared by the above preparation method, and the perfluorosulfonic acid resin catalyst is a particulate catalyst.

[0018] Compared with the prior art, the beneficial effects of the present invention can include at least the following: 1. By stabilizing the end groups of acyl fluoride type perfluorosulfonic acid resin through fluorination, the unstable end groups in the acyl fluoride type perfluorosulfonic acid resin can be fluorinated into stable fluorine-containing end groups, thereby improving the long-term stability of the perfluorosulfonic acid resin catalyst and avoiding the influence of unstable end groups on the color of the catalytic products during the oxidation process. 2. Through secondary granulation, the resin particles after end-group stabilization treatment are reshaped, which can repair the damage to the resin particles caused by the end-group stabilization treatment process and avoid excessive loss of resin particles during the catalytic reaction due to pulverization. 3. The resin particles are purified by solvent under high temperature and pressure, which removes low molecular weight components and residual additives in the preparation process of perfluorosulfonic acid resin. This can reduce the amount of low molecular weight polymer solvent in the reaction solvent during the reaction using perfluorosulfonic acid resin catalyst, thereby avoiding contamination of the product and its color. 4. A two-step granulation method can be used to prepare granular perfluorosulfonic acid resin catalysts with uniform product quality, stable performance, and good appearance through a simple process. 5. Using perfluorosulfonic acid resin with a high EW value reduces the dissolution of perfluorosulfonic acid resin with a low EW value during the reaction process using perfluorosulfonic acid resin catalyst, thereby improving the service life of perfluorosulfonic acid resin catalyst and avoiding contamination of the product. 6. The entire preparation process is easy to implement, without complex processes or harsh conditions, and is easy to industrialize.

[0019] The effects of this invention are not limited to those mentioned herein, and those skilled in the art will clearly understand other effects from the description of the claims. Detailed Implementation

[0020] Embodiments of the invention will be described in more detail below. However, the invention may be embodied in various different forms and should not be construed as being limited to the embodiments described herein. Rather, these embodiments are provided as examples so that the invention will be thorough and complete, and will fully convey aspects and features of the invention to those skilled in the art. Therefore, unnecessary processes, steps, and techniques that would allow those skilled in the art to fully understand aspects and features of the invention are not described. The terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meaning, but should be interpreted as meaning and concept consistent with the technical concept of the invention, based on the principle that the inventors can appropriately define the concepts of the terms to best describe the invention.

[0021] It is understood that the present invention can be modified in many alternative forms. It should be understood that the present invention is not limited to the specific forms disclosed, but is intended to cover all modifications, equivalents, and alternatives falling within the scope of the present invention.

[0022] Embodiments of the invention are described in more detail below. However, these embodiments are merely examples, and the invention is not limited thereto; rather, it is defined by the scope of the claims. The terminology used herein is for descriptive purposes only and is not intended to limit the invention.

[0023] As used herein, the terms “substantially,” “about,” and similar terms are used as approximate terms rather than as terms of degree, and are intended to take into account the inherent biases of measurements or calculations that would be recognized by one of ordinary skill in the art.

[0024] Furthermore, any numerical range described herein is intended to include all subranges containing the same numerical precision within the described range. For example, the range "1.0 to 10.0" is intended to include all subranges between the described minimum value of 1.0 and the described maximum value of 10.0 (and includes both the described minimum value of 1.0 and the described maximum value of 10.0), i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, while any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification and the claims to expressly describe any subranges contained within the scope expressly described herein.

[0025] The perfluorosulfonic acid resin catalyst and its preparation method of the present invention will be described in detail below.

[0026] One aspect of the present invention provides a method for preparing a perfluorosulfonic acid resin catalyst.

[0027] The preparation method includes the following steps: Step S1: Granulating the acyl fluoride type perfluorosulfonic acid resin to obtain a first intermediate product; Step S2: Performing end-group stabilization treatment on the first intermediate product to obtain a second intermediate product; Step S3: Granulating the second intermediate product to obtain a third intermediate product; Step S4: Performing a transformation treatment on the third intermediate product to transform the acyl fluoride type perfluorosulfonic acid resin into an H-type perfluorosulfonic acid resin to obtain a fourth intermediate product; Step S5: Removing impurities from the fourth intermediate product using a solvent to remove residual additives and oligomers to obtain a fifth intermediate product; Step S6: Drying the fifth intermediate product to obtain the perfluorosulfonic acid resin catalyst.

[0028] It is understood that the preparation method according to the present invention is not limited to this and may include other steps.

[0029] The following will describe each step in detail.

[0030] Step S1, primary granulation: The polymerized, coagulated, and dried perfluorosulfonic acid resin powder with an ion exchange equivalent (EW) of 1000 g / mol-1300 g / mol (preferably between 1050 g / mol and 1200 g / mol) is crushed to remove agglomerates and then fed into a twin-screw extruder for primary granulation. The temperature of each zone of the extruder is controlled between 240℃ and 350℃. The granulated resin strips with a diameter of 2mm-6mm obtained through extruder dies of different sizes are then cooled in a water-cooling tank and cut into resin particles with a thickness of 0.5mm-2mm using a designed and matched pelletizer to obtain the first intermediate product.

[0031] This invention aims to prepare a granular perfluorosulfonic acid resin catalyst. Compared with film-forming or solution-based perfluorosulfonic acid resin catalysts, granular perfluorosulfonic acid resin catalysts have advantages such as ease of use, simple operation, and convenient separation and recovery. Through a single granulation process, the polymerized perfluorosulfonic acid resin powder can be made into a granular form, facilitating subsequent steps.

[0032] Furthermore, the ion exchange equivalent (EW) of the acyl fluoride type perfluorosulfonic acid resin used in this invention is within the aforementioned range of 1000 g / mol to 1300 g / mol (preferably 1050 g / mol to 1200 g / mol). This is because perfluorosulfonic acid resins with an EW value below 1000 g / mol have better solubility in the partial solution of organic or polymeric reactions, and are easily dissolved in the solvent during the catalytic organic or polymeric reaction process, which shortens the catalytic lifetime of the catalyst and easily contaminates the reaction products. The EW value, also known as molar weight, is the weight of dry resin required to exchange 1 mol of the corresponding ions in the external solution. The unit is g / mol, and the relationship with the exchange capacity is: EW = 1000 / IEC.

[0033] Step S2, End-group stabilization treatment: The first intermediate product obtained in step S1 is first dried in a vacuum oven (60℃-90℃, absolute pressure controlled at 50kPa-80kPa) to remove moisture, and then placed in a fluorination reactor. Fluorine gas is introduced for end-group stabilization treatment, thereby removing unstable end groups in the acyl fluoride sulfonic acid resin. The fluorination process is as follows: The fluorination reactor is evacuated and purged three times with high-purity nitrogen gas, and then evacuated to absolute pressure. 20% fluorine-nitrogen gas (i.e., a mixture of fluorine and nitrogen gas with a volume ratio of 1:4) at 0.2MPa-1MPa is introduced, and the temperature is raised to 70℃-150℃. The pressure of the introduced fluorine-nitrogen gas is kept constant, and the mixture is stabilized for 10-30 hours. Preferably, 20% fluorine-nitrogen gas at 0.4MPa is introduced, and the temperature is raised to 80℃ for fluorination for 18 hours. Through step S2, the acyl fluoride or carboxyl end groups of the first intermediate product can be converted into trifluoromethyl end groups, thereby obtaining the second intermediate product.

[0034] During the polymerization of perfluorosulfonic acid resins, thermally unstable carboxylic acid or acyl fluoride end groups are generated. If used as a catalyst, these end groups can hydrolyze or dissolve in the reactants or solvents during catalysis, causing product contamination or affecting the product's color. Therefore, fluorination stabilization treatment can convert these unstable carboxylic acid or acyl fluoride end groups into stable trifluoromethyl end groups, preventing a reduction in the lifespan of the perfluorosulfonic acid resin catalyst and avoiding any impact on the catalytic reaction products.

[0035] Step S3, Secondary Granulation: The granular second intermediate product, after end-group fluorination stabilization treatment, is granulated a second time using a twin-screw extruder. The temperature of each section of the extruder is controlled between 250℃ and 370℃. Through secondary granulation, the perfluorosulfonic acid resin can be processed into resin strips with a diameter of 0.5mm-2mm (preferably 0.5mm-1mm), which are then cut into cylindrical particles with a thickness of 0.5mm-2mm (preferably 0.5mm-1mm) using a specialized pelletizer, thereby obtaining the third intermediate product. Compared with the first intermediate product described above, the third intermediate product can have a relatively small particle size.

[0036] The stabilization treatment using fluorinated end groups can damage the morphology of resin particles. If the second intermediate product obtained in step S2 is not subjected to secondary granulation but is directly subjected to the transformation treatment in step S4, the final perfluorosulfonic acid particle catalyst will suffer from severe pulverization and catalyst loss during the catalytic reaction.

[0037] To address this issue, this invention proposes a secondary granulation process for the end-group stabilized perfluorosulfonic acid resin particles, thereby reshaping the resin particles after end-group stabilization. This repairs the damage to the resin particles caused by the end-group stabilization process and prevents excessive loss of resin particles during the catalytic reaction due to pulverization.

[0038] Step S4, transformation treatment: The third intermediate product from secondary granulation is transformed under the following conditions: The resin particles are placed in an alkali metal hydroxide solution (preferably, a 5-30% KOH or NaOH solution) and heated to 60-100°C for 15-40 hours to transform the acyl fluoride granular resin into a potassium or sodium form resin. After cooling, the resin particles are discharged and filtered. Residual alkali is washed away with 2-5 times the weight of high-purity water relative to the resin mass. After filtering out the water, the resin particles are added to a strong acid solution (preferably a 10-30% nitric acid solution) and heated to 60-100°C for 15-40 hours to transform the potassium or sodium form resin into an acidic perfluorosulfonic acid resin. Then, the resin is washed 3-8 times with 5-10 times its weight of water to remove residual nitric acid. Finally, the surface moisture of the resin particles is dried to obtain the fourth intermediate product.

[0039] Through a two-step transformation, perfluorosulfonic acid resins can acquire the ability to release free H+. + , becomes H + This type of resin possesses the function of a solid protic acid catalyst.

[0040] According to the present invention, the perfluorosulfonic acid resin is first subjected to fluorination end-group stabilization treatment, and then subjected to hydrolysis and acidification transformation. This is because if hydrolysis and acidification transformation is performed first, followed by fluorination end-group stabilization treatment, it will already be converted to H... + The fluorinated perfluorosulfonic acid resin will revert to the acyl fluoride type and lose its catalytic function. Furthermore, the converted perfluorosulfonic acid resin contains a significant amount of moisture, making fluorination at this stage potentially dangerous. Additionally, the violent reaction between fluorine and water releases a large amount of heat, causing the resin to carbonize.

[0041] Therefore, the present invention avoids the above-mentioned problems by reasonably setting the order of each step.

[0042] Step S5, Impurity Removal Treatment: The transformed hydrogen-form perfluorosulfonic acid resin particles (i.e., the fourth intermediate product) are placed in a high-pressure reactor, and a solvent (such as at least one of ethanol, acetone, isopropanol, and diethyl ether) is added to treat the perfluorosulfonic acid resin particles, causing the low molecular weight resin and residual additives (e.g., emulsifying agents derived from the polymerization process) in the fourth intermediate product to dissolve in the solvent, thereby obtaining the fifth intermediate product. The mass ratio of perfluorosulfonic acid resin particles to solvent is between 1:2 and 1:10. The pressure is controlled between 0.5 MPa and 2 MPa, the temperature is controlled between 100°C and 200°C, and the dissolution time is controlled between 1 and 10 hours. Preferably, the mass ratio of perfluorosulfonic acid resin particles to solvent is between 1:3 and 1:6, the pressure is controlled between 1 MPa and 1.5 MPa, the temperature is controlled between 120°C and 160°C, and the dissolution time is controlled between 2 and 5 hours.

[0043] By treating perfluorosulfonic acid resin particles under high temperature and high pressure, it is possible to effectively remove low molecular weight resins mixed in intermediate products and residual additives from the preparation of perfluorosulfonic acid resins through polymerization reactions. This can reduce the amount of low molecular weight polymer solvents entering the reaction solvent during the reaction process using perfluorosulfonic acid resin catalysts, thereby avoiding contamination of the product and its color.

[0044] Step S6, Drying treatment: After step S5 is completed, the high-pressure reactor is cooled and depressurized, the resin particles are taken out, the solvent is filtered out, and the resin particles are placed in a vacuum oven. First, the vacuum is drawn to -50Kpa to -80KPa for half an hour, and then the oven is heated to 60℃-90℃ and the temperature is maintained for 2-8 hours to remove the residual solvent in the resin, thereby obtaining the perfluorosulfonic acid resin catalyst of the present invention.

[0045] According to the present invention, through the above steps, a perfluorosulfonic acid resin catalyst with high catalytic single-pass conversion rate, better product appearance and longer catalytic life can be prepared.

[0046] Another aspect of the present invention provides a particulate perfluorosulfonic acid resin catalyst, which is prepared by the above method.

[0047] To provide a clearer understanding of the technical content of this invention, the following embodiments are provided for detailed description. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the raw materials involved in the following embodiments are all commercially available products that can be purchased from the market or prepared using existing methods.

[0048] The above-described technical features of the present invention and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions.

[0049] Example 1 The condensed and dried powdered acyl fluoride perfluorosulfonic acid resin (with an exchange equivalent (EW) of 1100 designed in the process formulation) from the polymerization reactor is extruded through a twin-screw extruder with a ground joint diameter of 3 mm (the five heating zones before the extrusion die of the screw extruder are 260-260-270-280-300℃ respectively). The extruded resin strip with a diameter of approximately 3.5 mm is then cut into granules with a thickness of approximately 1.5 mm by a pelletizer. These granules are then placed in a fluorination reactor for end-group stabilization treatment to remove residual unstable end groups in the resin. 20% fluorine-nitrogen gas is introduced, the fluorination temperature is 100℃, the fluorine gas pressure is controlled at 0.4 MPa, and fluorination is continued for 18 hours. Next, the resin granules were removed from the fluorination reactor and subjected to secondary screw extrusion granulation using a twin-screw extruder with a ground glass inlet diameter of 0.5 mm (the five heating zones before the extrusion die of the screw extruder were 270-270-280-290-320℃). The extruded resin strips with a diameter of approximately 0.7 mm were then cut into granules with a thickness of approximately 0.5 mm by a pelletizer. The resin granules were then converted to sodium-form resin by incubating them in a 15% NaOH solution at 90℃ for 20 hours. The sodium-form resin granules were then placed in a 15% nitric acid solution at 90℃ for 20 hours to convert them to hydrogen-form perfluorosulfonic acid resin. The resin was then washed with high-purity water to remove residual nitric acid and filtered dry. Subsequently, an ethanol solution (the mass ratio of perfluorosulfonic acid resin particles to ethanol is 1:4) was added to a high-pressure reactor and the mixture was treated at 1 MPa pressure and 120°C for 5 hours to remove residual emulsifiers and low molecular weight polymers from the resin. The mixture was then baked in a vacuum oven at 80°C / -50 kPa for 5 hours. After drying to remove residual solvents, the granular perfluorosulfonic acid protonic acid catalyst of this invention was obtained.

[0050] Comparative Example 1 Particulate perfluorosulfonic acid protic acid catalysts were prepared using a method similar to that in Example 1, except that the fluorinated end-group stabilization step and the high-temperature, high-pressure solvent purification step were not included.

[0051] Comparative Example 2 Particulate perfluorosulfonic acid protic acid catalysts were prepared using a method similar to that in Example 1, except that the fluorinated end-group stabilization step was not included.

[0052] Comparative Example 3 Particulate perfluorosulfonic acid protic acid catalysts were prepared using a method similar to that in Example 1, except that the high-temperature, high-pressure solvent purification step was not included.

[0053] Comparative Example 4 Particulate perfluorosulfonic acid protic acid catalysts were prepared using a method similar to that in Example 1, except that a second granulation step was not included.

[0054] Catalytic effect test The perfluorosulfonic acid protonic acid catalysts prepared in the above examples and comparative examples were each dried in a vacuum oven at 130°C for 3 hours, and then tested as THF polymerization catalysts. Using 10 parts of dried catalyst, 84 parts of THF, 3 parts of acetic acid, and 3 parts of acetic anhydride, THF polymerization was carried out at room temperature for 2.5 hours with stirring by a magnetic stir bar at approximately 250 rpm. The single-pass conversion rate and product appearance were checked and compared using the following method: The product was quickly separated from the catalyst by filtration. After measuring the filtrate with a turbidity meter, the separated catalyst was soaked and washed with THF solvent for 1 hour, then removed and dried in an oven at 130°C for 3 hours. The product was then weighed, and the catalyst loss was calculated. The filtrate was added to a rotary evaporator and distilled at 80°C under normal pressure for 1 hour until no more droplets were distilled out. The residue was further distilled at 150°C for 1 hour (using a simple distillation apparatus). After cooling, the mass M of the remaining PTMEA was weighed. The THF single-pass conversion rate was calculated as follows: Meanwhile, the turbidity of the distillation residue was measured using a turbidimeter. The results are shown in Table 1 below.

[0055] Table 1 As shown in Table 1, the THF polymerization conversion rate of the perfluorosulfonic acid protonic acid catalyst prepared in Example 1 is significantly higher than that of the perfluorosulfonic acid protonic acid catalysts prepared in Comparative Examples 1 to 4, indicating that the perfluorosulfonic acid catalyst prepared by the method of the present invention exhibits a higher catalytic conversion rate. The turbidity of the filtrate and distillate after catalytic reaction of the perfluorosulfonic acid protonic acid catalyst prepared in Example 1 is significantly lower than that of the perfluorosulfonic acid protonic acid catalysts prepared in Comparative Examples 1 to 4, indicating that the soluble content of the perfluorosulfonic acid catalyst prepared by the method of the present invention is lower. The catalyst loss of the perfluorosulfonic acid protonic acid catalyst prepared in Example 1 is significantly lower than that of the perfluorosulfonic acid protonic acid catalysts prepared in Comparative Examples 1 to 4, indicating that the perfluorosulfonic acid catalyst prepared by the method of the present invention has a longer service life.

[0056] Finally, it should be emphasized that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a perfluorosulfonic acid resin catalyst, characterized in that, The preparation method includes the following steps: Step S1: Granulate the acyl fluoride type perfluorosulfonic acid resin to obtain the first intermediate product; Step S2: The first intermediate product is subjected to end-group stabilization treatment to obtain the second intermediate product; Step S3: Granulate the second intermediate product to obtain the third intermediate product; Step S4: The third intermediate product is transformed into H-type perfluorosulfonic acid resin to obtain the fourth intermediate product. Step S5: Use a solvent to remove impurities from the fourth intermediate product, removing residual additives and oligomers, to obtain the fifth intermediate product; Step S6: Dry the fifth intermediate product to obtain the perfluorosulfonic acid resin catalyst.

2. The preparation method according to claim 1, characterized in that, In step S1, the ion exchange equivalent (EW) of the acyl fluoride type perfluorosulfonic acid resin is between 1000 g / mol and 1300 g / mol. Step S1 includes: granulating the polymerized, condensed, and dried acyl fluoride perfluorosulfonic acid resin using an extruder to obtain a granular first intermediate product.

3. The preparation method according to claim 1, characterized in that, Step S2 includes: placing the first intermediate product in a reactor, introducing a processing gas, and performing an end-group stabilization treatment at a first predetermined pressure and a first predetermined temperature for a first predetermined time, so that the acyl fluoride or carboxyl end groups of the first intermediate product are converted into trifluoromethyl end groups, thereby obtaining the second intermediate product. The processing gas is a mixture of fluorine and nitrogen in a volume ratio of 1:

4. The first predetermined pressure is 0.2 MPa to 1 MPa. The first predetermined temperature is 70°C to 150°C. The first scheduled time is 10 to 30 hours.

4. The preparation method according to claim 3, characterized in that, The first predetermined pressure is 0.4 MPa. The first predetermined temperature is 80°C. The first scheduled time is 18 hours.

5. The preparation method according to claim 1, characterized in that, Step S3 includes: granulating the second intermediate product using an extruder to obtain a granular third intermediate product. The particle size of the third intermediate product is smaller than that of the first intermediate product.

6. The preparation method according to claim 1, characterized in that, Step S4 includes: treating the third particles with an alkali metal hydroxide solution at a second predetermined pressure and a second predetermined temperature for a second predetermined time, thereby converting the acyl fluoride type perfluorosulfonic acid resin into an alkali metal ionic type perfluorosulfonic acid resin; then treating the alkali metal ionic type perfluorosulfonic acid resin with a strong acid solution at a third predetermined pressure and a third predetermined temperature for a third predetermined time to obtain a product containing H... + The fourth intermediate product of perfluorosulfonic acid resin.

7. The preparation method according to claim 1, characterized in that, The alkali metal hydroxide solution is a KOH solution or a NaOH solution. The strong acid solution is a 10wt% to 30wt% nitric acid solution. The second predetermined pressure is atmospheric pressure. The second predetermined temperature is 60°C to 100°C. The second scheduled time is 15 to 40 hours. The third predetermined pressure is atmospheric pressure. The third predetermined temperature is 60°C to 100°C. The third predetermined time is 15 to 40 hours.

8. The preparation method according to claim 1, characterized in that, Step S5 includes: placing the fourth intermediate product in a high-pressure reactor, adding a solvent, and treating it at a second predetermined pressure and a second predetermined temperature for a second predetermined time. The solvent includes at least one selected from ethanol, acetone, isopropanol, and diethyl ether. The mass ratio of the fourth intermediate to the solvent is 1:2 to 1:

10. The second predetermined pressure is 0.5 MPa to 2 MPa. The second predetermined temperature is 100°C to 200°C. The second scheduled time is 1 hour to 10 hours.

9. The preparation method according to claim 8, characterized in that, The mass ratio of the fourth intermediate to the solvent is 1:3 to 1:

6. The second predetermined pressure is 1 MPa to 1.5 MPa. The second predetermined temperature is 120°C to 160°C. The second scheduled time is 2 to 5 hours.

10. A perfluorosulfonic acid resin catalyst, characterized in that, The perfluorosulfonic acid resin catalyst is prepared by the preparation method according to any one of claims 1 to 9. The perfluorosulfonic acid resin catalyst is a particulate catalyst.

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