Preparation and application of bio-based green polyion liquid polyacid desulfurization catalyst

Abstract

The invention belongs to the technical field of desulfurization catalyst preparation, and particularly relates to preparation and application of a bio-based green polyion liquid polyacid desulfurization catalyst. Comprising the following steps: acidifying a sodium alginate solution to form a gel-state product; dissolving the gel-state product, triethanolamine and a catalyst in a first solvent for esterification reaction to obtain a precursor; the precursor and a brominated alkyl compound are dissolved in a second solvent for quaternization reaction, and bio-based polyion liquid is obtained; and adding the bio-based polyion liquid into the polyoxometallate solution to obtain the bio-based green polyion liquid polyacid desulfurization catalyst. According to the invention, a sodium alginate natural biopolymer is taken as a precursor substance, and the green polyion liquid is synthesized through series reaction modification, so that the harm of the traditional chemical polyion liquid to the environment is reduced, and meanwhile, the synthesis steps are simplified; the bio-based green polyion liquid polyacid catalyst is obtained by immobilization with polyoxometallate through reactions such as ion exchange, and the desulfurization efficiency is high.

Description

Technical Field

[0001] The invention belongs to the technical field of desulfurization catalyst preparation, and specifically relates to the preparation and application of a bio-based green polyionic liquid polyacid desulfurization catalyst. Background Art

[0002] At present, petroleum fuel is still the most widely used and main energy source. An inevitable problem is that the combustion of sulfur compounds in petroleum fuel will cause serious environmental problems such as acid rain and endanger human health. Thiophene sulfides account for more than 80% of the total sulfur content in petroleum fuel, of which 70% are aromatic sulfides such as benzothiophene (BT), dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). Therefore, how to reduce or even remove sulfur compounds in petroleum fuel has become a hot research issue.

[0003] The most commonly used desulfurization method in industry is hydrodesulfurization (HDS), which can effectively remove small molecular sulfur compounds such as hydrogen sulfide, mercaptans and sulfides. However, even after many optimizations and improvements, HDS still has many defects, including the expensive price of hydrogen, the necessary conditions of high temperature and high pressure, the low efficiency of removing heteroaromatic compounds, and the selectivity of products caused by the hydrogenation of π-π bonds of olefins (more hydrogen is required). Therefore, many alternative or supplementary desulfurization technologies have been developed. Oxidative desulfurization (ODS) has become a more and more researched technology due to its mild operating conditions, high selectivity and easy separation of oxidized sulfides. Among them, the function and structure of the catalyst are one of the key factors affecting the efficiency of ODS. In recent years, oxidative desulfurization has mostly been studied using organic acids, metal oxides and ionic liquids as catalysts. However, organic acid catalysts will cause equipment corrosion after long-term use. After the reaction, the separation and regeneration of organic acid catalysts have not been properly treated, and ionic liquids also have problems of high viscosity and high cost. Therefore, the preparation of highly active, highly stable and low-cost catalysts is the future development direction of oxidative desulfurization technology.

[0004] Polyoxometalates (POMs, referred to as polyacids) are green catalysts with broad application prospects and good catalytic performance, but they have disadvantages such as small specific surface area and difficult recycling, which can be improved by combining with carriers. Polyionic liquids (PILs) are macromolecular polymers with a non-crystalline structure formed by grafting ionic liquid (IL) monomers on the polymer skeleton. They can not only supplement and amplify the functions of ionic liquids, achieve functions that ionic liquids cannot achieve, but also overcome the defects of traditional ionic liquids to a large extent. PILs have large specific surface area, rich and stable chemical properties, high thermal stability, and adjustable solubility. They are ideal materials for preparing high-performance amphiphilic new organic-inorganic catalysts POMs-PILs. POMs-PILs have both the catalytic oxidation activity of POMs and the unique liquid phase of polyionic liquids, overcoming the shortcomings of polyoxometalates and ionic liquids. The prepared powder catalyst is conducive to separation and reuse, and has broad prospects in actual production. However, the current preparation and research of PILs is designed and synthesized based on chemical substances. The complex synthesis process and the inevitable large-scale use of chemical substances bring tremendous pressure and harm to the environment and biological health. Summary of the invention

[0005] In order to solve the above problems, the present invention provides the preparation and application of bio-based green polyionic liquid polyacid desulfurization catalyst. Sodium alginate natural biopolymer is selected as a precursor, and a green polyionic liquid is synthesized through a series of reactions to modify and synthesize, which greatly reduces the damage of traditional chemical-based polyionic liquids to the environment while simplifying the synthesis steps. The final product also has the excellent properties of polyionic liquids. At the same time, the bio-based green polyionic liquid polyacid catalyst is obtained by immobilizing with polyoxometalates through ion exchange and other reactions. The preparation reaction conditions are mild, the operation is simple, and the reaction steps are fewer. Controllable PILs can be prepared and the amount of catalyst can be significantly reduced when the same polymerization rate is obtained.

[0006] The present invention solves the above technical problems through the following technical solutions.

[0007] One of the purposes of the present invention is to provide a method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst, comprising the following steps: S1. Acidify the sodium alginate solution to form a gel product.

[0008] S2. Under a protective gas atmosphere, dissolving the gel product, triethanolamine and a catalyst in a first solvent, and performing an esterification reaction to obtain a precursor.

[0009] S3. Under a protective gas atmosphere, the precursor and the alkyl bromide compound are dissolved in a second solvent to carry out a quaternization reaction to obtain a bio-based polyionic liquid.

[0010] S4. Adding the bio-based polyionic liquid into the polyoxometalate solution at room temperature, stirring to carry out ion exchange so that the polyoxometalate is immobilized on the bio-based polyionic liquid, thereby obtaining a bio-based green polyionic liquid polyacid desulfurization catalyst.

[0011] Furthermore, the mass ratio of the bio-based polyionic liquid to the polyoxometalate in the polyoxometalate solution is 1:1-5.

[0012] Furthermore, the molar ratio of the gel-state product to triethanolamine is 1:1-3, the amount of the catalyst used is 0.2 wt.%-0.4 wt.% of the total amount of the gel-state product, and the catalyst is p-toluenesulfonic acid.

[0013] Furthermore, the esterification reaction temperature is 80° C. to 120° C., the time is 4 h to 8 h, and the protective gas is nitrogen.

[0014] Furthermore, the molar ratio of the precursor to the alkyl bromide compound is 1:1-3, and the alkyl bromide compound is hexadecane bromide.

[0015] Furthermore, the temperature of the quaternization reaction is 60° C. to 150° C., the time is 3 h to 8 h, and the protective gas is nitrogen.

[0016] Furthermore, the sodium alginate solution is an aqueous solution of sodium alginate with a concentration of 0.02 g / mL to 0.08 g / mL. The acidification method is to add hydrochloric acid to the sodium alginate solution until a gel product is generated, and the concentration of the hydrochloric acid is 1 M to 3 M. After the gel product is generated, it is freeze-dried at -40°C.

[0017] The second object of the present invention is to provide a bio-based green polyionic liquid polyacid desulfurization catalyst prepared by the above preparation method.

[0018] The third object of the present invention is to provide the use of the above-mentioned bio-based green polyionic liquid polyacid desulfurization catalyst in the desulfurization of gasoline and diesel.

[0019] Furthermore, the liquid polyacid desulfurization catalyst is used in combination with hydrogen peroxide, hydrogen peroxide is used as an oxidant, the usage ratio of the liquid polyacid desulfurization catalyst to gasoline and diesel is 0.05g-0.2g:100ml, and the oxygen-sulfur ratio of hydrogen peroxide to gasoline and diesel is 1:2-9.

[0020] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention uses sodium alginate natural biopolymer as a precursor, acidifies the precursor, then uses triethanolamine to aminoesterify its carboxyl group, and finally quaternizes the amino group with polyion, and introduces Br -, thereby optimizing its catalytic performance to obtain brominated polyionic liquids, that is, green polyionic liquids are synthesized through a series of modified reactions, which greatly reduces the harm of traditional chemical-based polyionic liquids to the environment while simplifying the synthesis steps. The final product also has the excellent properties of polyionic liquids. The obtained bio-based polyionic liquids are immobilized with polyoxometalates through ion exchange and other reactions to obtain bio-based green polyionic liquid polyacid catalysts, and Br is introduced into the catalyst structure unit through brominated alkyl compounds. - The induction effect can increase the active sites of the catalyst, thereby optimizing its catalytic performance. The preparation reaction conditions are mild, the operation is simple, and the reaction steps are fewer. Controllable PILs can be prepared and the amount of catalyst can be significantly reduced when obtaining the same polymerization rate.

[0021] (2) The present invention uses bio-based green polyionic liquid to immobilize polyacid to obtain a shaped catalyst, which meets the requirements of green chemical clean production and has a significant desulfurization effect when used for gasoline and diesel desulfurization with high desulfurization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The X-ray diffraction diagram of the bio-based green polyionic liquid polyacid desulfurization catalyst of Examples 1 to 4 of the present invention is shown in FIG. Figure 1 (a) is the full spectrum of X-ray diffraction, and (b) is the enlarged view of the characteristic peaks of X-ray diffraction of Examples 2 to 4.

[0023] Figure 2 The bio-based green polyionic liquid polyacid desulfurization catalyst prepared in Example 1 of the present invention 1 HNMR spectrum.

[0024] Figure 3 This is a desulfurization rate curve of the bio-based green polyionic liquid polyacid desulfurization catalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0027] However, the current preparation and research of PILs are designed and synthesized based on chemical substances, such as vinyl imidazole, acrylates, and quaternary ammonium salts. The complex synthesis process and the inevitable large-scale use of chemical substances bring tremendous pressure and harm to the environment and biological health.

[0028] Based on the above problems, the present invention provides a method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst, comprising the following steps: S1. Acidify the sodium alginate solution to form a gel product.

[0029] S2. Under a protective gas atmosphere, dissolving the gel product, triethanolamine and a catalyst in a first solvent, and performing an esterification reaction to obtain a precursor.

[0030] S3. Under a protective gas atmosphere, the precursor and the alkyl bromide compound are dissolved in a second solvent to carry out a quaternization reaction to obtain a bio-based polyionic liquid.

[0031] S4. Adding the bio-based polyionic liquid into the polyoxometalate solution at room temperature, stirring to carry out ion exchange so that the polyoxometalate is immobilized on the bio-based polyionic liquid, thereby obtaining a bio-based green polyionic liquid polyacid desulfurization catalyst.

[0032] The present invention uses sodium alginate natural biopolymer as a precursor, performs an acidification treatment on the precursor, then selects triethanolamine to perform amino esterification modification on the carboxyl group, and finally performs quaternary ammonium polyion modification on the amino group to obtain a brominated polyionic liquid, that is, a green polyionic liquid is synthesized through a series of reaction modifications, which greatly reduces the damage of traditional chemical-based polyionic liquids to the environment while simplifying the synthesis steps. The final product also has the excellent properties of polyionic liquids. The unit structure formula of the obtained bio-based polyionic liquid is as follows: .

[0033] At the same time, bio-based green polyionic liquid polyacid catalysts are obtained by immobilizing polyoxometalates through ion exchange reactions. The preparation reaction conditions are mild, the operation is simple, and the reaction steps are fewer. Controllable PILs can be prepared and the amount of catalyst can be significantly reduced while obtaining the same polymerization rate.

[0034] In a specific embodiment, the mass ratio of the bio-based polyionic liquid to the polyoxometalate in the polyoxometalate solution is 1: 1 to 5. The bio-based polyionic liquid carries the polyoxometalate active component, that is, carries the effective amount of the polyacid active component, and the polyacid active component is highly dispersed on the polyionic liquid. Therefore, the amount of the bio-based polyionic liquid determines the effective amount of the polyacid active component, and the increase has an impact on the activity of the polyacid.

[0035] In a specific embodiment, the molar ratio of the gel product to triethanolamine is 1:1-3, the amount of the catalyst is 0.2wt.%-0.4wt.% of the total amount of the gel product, and the catalyst is p-toluenesulfonic acid. In the present invention, the hydroxyl group in the triethanolamine and the carboxyl group in the gel product undergo an esterification reaction under the action of the catalyst, and the gel product, i.e., diatomaceous acid, is amino-esterified and grafted with triethanolamine.

[0036] In a specific embodiment, the temperature of the esterification reaction is 80° C. to 120° C., the time is 4 h to 8 h, and the protective gas is nitrogen.

[0037] In a specific embodiment, the molar ratio of the precursor to the alkyl bromide compound is 1:1-3, and the alkyl bromide compound is hexadecane bromide. Br is introduced into the catalyst structural unit by the alkyl bromide compound. - The inductive effect can increase the active sites of the catalyst and thus optimize its catalytic performance.

[0038] In a specific embodiment, the temperature of the quaternization reaction is 60° C. to 150° C., the time is 3 h to 8 h, and the protective gas is nitrogen.

[0039] The sodium alginate solution is a sodium alginate aqueous solution with a concentration of 0.02 g / mL to 0.08 g / mL. The acidification method is to add hydrochloric acid to the sodium alginate solution until a gel product is generated. The concentration of hydrochloric acid is 1 M to 3 M. After the gel product is generated, it is freeze-dried at -40°C. The purpose of freeze-drying is to form a gel product, reduce voids, and improve efficient binding with polyacids.

[0040] The present invention provides a bio-based green polyionic liquid polyacid desulfurization catalyst prepared by the above preparation method. The present invention adopts bio-based green polyionic liquid to immobilize polyacid to obtain a formed catalyst, which meets the requirements of green chemical clean production and increases its research and use value.

[0041] The present invention also provides the use of the above-mentioned bio-based green polyionic liquid polyacid desulfurization catalyst in the desulfurization of gasoline and diesel. In a specific embodiment, the polyionic liquid polyacid desulfurization catalyst is used in combination with hydrogen peroxide, and hydrogen peroxide is used as an oxidant; wherein the polyionic liquid polyacid desulfurization catalyst and gasoline and diesel use ratio is 0.05g-0.2g:100ml, and the oxygen-sulfur ratio of hydrogen peroxide to gasoline and diesel is 1:2-9.

[0042] The invention is further described below through specific examples.

[0043] Example 1 A method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst comprises the following steps: S1. Dissolve 20 g of sodium alginate in 500 mL of deionized water. After the sodium alginate is completely dissolved, titrate it with 2 M dilute hydrochloric acid to obtain a gel-state product H-ALG, which is then freeze-dried at -40°C.

[0044] S2. Under a nitrogen atmosphere, 9.71 g of H-ALG (0.05 mol) and 7.46 g of triethanolamine (0.05 mol) were added to a three-necked flask, and then 80 mL of NN-dimethylformamide solvent (DMF) and 0.02 g of p-toluenesulfonic acid (PTSA) catalyst were added. The mixture was heated under reflux at 100 °C for esterification for 6 h. After the reaction, DMF was evaporated under reduced pressure, and PTSA was removed by washing with petroleum ether several times to obtain the precursor product N-ALG.

[0045] S3. Under a nitrogen atmosphere, 6.87 g of the precursor product N-ALG (0.02 mol) and 6.11 g of hexadecane bromide (0.02 mol) were dissolved in 60 mL of xylene and heated under reflux at 100 °C for quaternization reaction for 5 h. After the reaction, xylene was evaporated under reduced pressure to obtain a bio-based polyionic liquid.

[0046] S4. Ultrasonic dissolve 0.2 g of polyoxometalate in 5 mL of DMF to obtain a polyoxometalate solution. Slowly add 0.3 g of bio-based polyionic liquid into the polyoxometalate solution at room temperature and stir for 24 h to perform ion exchange so that the polyoxometalate is immobilized on the bio-based polyionic liquid. Then, centrifuge and remove the supernatant. Dry the precipitate to obtain a bio-based green polyionic liquid polyacid desulfurization catalyst, named PP-1.

[0047] Example 2 A method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst comprises the following steps: S1. Dissolve 20 g of sodium alginate in 500 mL of deionized water. After the sodium alginate is completely dissolved, titrate it with 2 M dilute hydrochloric acid to obtain a gel-state product H-ALG, which is then freeze-dried at -40°C.

[0048] S2. Under a nitrogen atmosphere, 9.71 g of H-ALG (0.05 mol) and 7.46 g of triethanolamine (0.05 mol) were added to a three-necked flask, and then 80 mL of DMF and 0.02 g of PTSA catalyst were added. The mixture was heated under reflux at 100 °C for esterification for 6 h. After the reaction, DMF was evaporated under reduced pressure, and PTSA was removed by washing with petroleum ether several times to obtain the precursor product N-ALG.

[0049] S3. Under a nitrogen atmosphere, 6.87 g of the precursor product N-ALG (0.02 mol) and 6.11 g of hexadecane bromide (0.02 mol) were dissolved in 60 mL of xylene and heated under reflux at 100 °C for quaternization reaction for 5 h. After the reaction, xylene was evaporated under reduced pressure to obtain a bio-based polyionic liquid.

[0050] S4. Ultrasonic dissolve 0.4 g of polyoxometalate in 5 mL of DMF to obtain a polyoxometalate solution. Slowly add 0.3 g of bio-based polyionic liquid into the polyoxometalate solution at room temperature, stir for 24 hours to perform ion exchange to immobilize the polyoxometalate on the bio-based polyionic liquid, then centrifuge and remove the supernatant. Dry the precipitate to obtain a bio-based green polyionic liquid polyacid desulfurization catalyst, named PP-2.

[0051] Example 3 A method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst comprises the following steps: S1. Dissolve 20 g of sodium alginate in 500 mL of deionized water. After the sodium alginate is completely dissolved, titrate it with 2 M dilute hydrochloric acid to obtain a gel-state product H-ALG, which is then freeze-dried at -40°C.

[0052] S2. Under a nitrogen atmosphere, 9.71 g of H-ALG (0.05 mol) and 7.46 g of triethanolamine (0.05 mol) were added into a three-necked flask, and then 80 mL of DMF and 0.02 g of PTSA catalyst were added. The mixture was heated under reflux at 100 °C for esterification reaction for 6 h. After the reaction, DMF was evaporated under reduced pressure, and PTSA was removed by washing with petroleum ether several times to obtain the precursor product N-ALG.

[0053] S3. Under a nitrogen atmosphere, 6.87 g of the precursor product N-ALG (0.02 mol) and 6.11 g of hexadecane bromide (0.02 mol) were dissolved in 60 mL of xylene and heated under reflux at 100 °C for quaternization reaction for 5 h. After the reaction, xylene was evaporated under reduced pressure to obtain a bio-based polyionic liquid.

[0054] S4. Ultrasonic dissolve 0.6 g of polyoxometalate in 5 mL of DMF to obtain a polyoxometalate solution. Slowly add 0.3 g of bio-based polyionic liquid into the polyoxometalate solution at room temperature, stir for 24 hours to perform ion exchange to immobilize the polyoxometalate on the bio-based polyionic liquid, then centrifuge and remove the supernatant. Dry the precipitate to obtain a bio-based green polyionic liquid polyacid desulfurization catalyst, named PP-3.

[0055] Example 4 A method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst comprises the following steps: S1. Dissolve 20 g of sodium alginate in 500 mL of deionized water. After the sodium alginate is completely dissolved, titrate it with 2 M dilute hydrochloric acid to obtain a gel-state product H-ALG, which is then freeze-dried at -40°C.

[0056] S2. Under a nitrogen atmosphere, 9.71 g of H-ALG (0.05 mol) and 7.46 g of triethanolamine (0.05 mol) were added into a three-necked flask, and then 80 mL of DMF and 0.02 g of PTSA catalyst were added. The mixture was heated under reflux at 100 °C for esterification reaction for 6 h. After the reaction, DMF was evaporated under reduced pressure, and PTSA was removed by washing with petroleum ether several times to obtain the precursor product N-ALG.

[0057] S3. Under a nitrogen atmosphere, 6.87 g of the precursor product N-ALG (0.02 mol) and 6.11 g of hexadecane bromide (0.02 mol) were dissolved in 60 mL of xylene and heated under reflux at 100 °C for quaternization reaction for 5 h. After the reaction, xylene was evaporated under reduced pressure to obtain a bio-based polyionic liquid.

[0058] S4. Ultrasonic dissolve 0.8 g of polyoxometalate in 5 mL of DMF to obtain a polyoxometalate solution. Slowly add 0.3 g of bio-based polyionic liquid into the polyoxometalate solution at room temperature, stir for 24 hours to perform ion exchange to immobilize the polyoxometalate on the bio-based polyionic liquid, then centrifuge and remove the supernatant. Dry the precipitate to obtain a bio-based green polyionic liquid polyacid desulfurization catalyst, named PP-4.

[0059] The results of structure and performance tests on the bio-based green polyionic liquid polyacid desulfurization catalyst and bio-based polyionic liquid prepared in Examples 1 to 4 are as follows: Figure 1 The X-ray diffraction diagram of the bio-based green polyionic liquid polyacid desulfurization catalyst of Examples 1 to 4 of the present invention is shown in FIG. Figure 1 (a) is the full spectrum of X-ray diffraction, and (b) is the enlarged view of the characteristic peaks of X-ray diffraction of Examples 2 to 4. Figure 1 As shown, POM is in 2 θ =7°~10°, 16°~22° and 25°~38° show the typical diffraction peaks of Keggin type anion crystal structure. θ=15°~30° broad diffraction peak is the characteristic peak of polyionic liquid. The characteristic peaks of polyacid and polyionic liquid appeared at the corresponding positions of the desulfurization catalyst obtained by introducing polyionic liquid to modify polyacid, indicating that polyoxometalate was successfully loaded on polyionic liquid. At the same time, the appearance of amorphous structure further proves that polyacid anion is highly dispersed in polyionic liquid in the form of single molecule.

[0060] Figure 2 The bio-based green polyionic liquid polyacid desulfurization catalyst prepared in Example 1 of the present invention 1 HNMR diagram. The molecular structure of bio-based polyionic liquid polyacid desulfurization catalysis is shown by 1 HNMR analysis, such as Figure 2 As shown, due to the introduction of Br into the catalyst structural unit - The inductive effect caused a certain chemical shift in the nuclear magnetic resonance position of the catalyst. The vibration of the protons belonging to the long-chain alkyl in the catalyst repeating unit occurred at 0.88 ppm, 1.55 ppm, 2.01 ppm, and 3.41 ppm, and the ethylene protons belonging to TEA vibrated at 1.63 ppm, 1.85 ppm, and 3.64 ppm. The appearance of the protons of the precursor substance between 1.43 ppm, 4.05 ppm, and 5.34 ppm indicated that the esterification and quaternization reactions occurred successfully, proving the integrity of the molecular structure of the bio-based polyionic liquid polyacid catalyst.

[0061] The bio-based green polyionic liquid polyacid catalyst prepared in Example 3 is used for gasoline and diesel desulfurization. At this time, the bio-based green polyionic liquid polyacid catalyst prepared in Example 3 is named BH-ALG@POM, which includes the following steps: 0.208 g of dibenzothiophene was weighed and dissolved in 50 mL of n-octane solution to prepare a simulated fuel with a sulfur content of 1000 ppm. An oxidative desulfurization test was carried out. 25 mL of the prepared simulated fuel was added with 0.2 g of the bio-based green polyionic liquid polyacid catalyst BH-ALG@POM prepared in Example 3, and hydrogen peroxide was added. The oxygen-sulfur ratio of hydrogen peroxide to the simulated fuel was 1:4. Gas chromatography was used to detect the change in sulfur content of the system during the entire desulfurization test.

[0062] Figure 3 This is a desulfurization rate curve of the bio-based green polyionic liquid polyacid catalyst prepared in Example 3 of the present invention. Figure 3 As shown, the bio-based green polyionic liquid polyacid catalyst prepared in the present invention has an obvious desulfurization effect, and the desulfurization efficiency can reach 95% within 120 minutes.

[0063] It should be noted that when the present invention involves a numerical range, it should be understood that the two endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as those in the embodiments, in order to avoid redundancy, the present invention describes a preferred embodiment. Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they know the basic creative concept. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0064] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing a bio-based green polyionic liquid polyacid desulfurization catalyst, characterized in that: The following steps are involved: Acidifying the sodium alginate solution to form a gel-like product; Under a protective gas atmosphere, the gel product, triethanolamine and a catalyst are dissolved in a first solvent to carry out an esterification reaction to obtain a precursor; Under a protective gas atmosphere, the precursor and the bromoalkyl compound are dissolved in a second solvent to carry out a quaternization reaction to obtain a bio-based polyionic liquid; The bio-based polyionic liquid is added into the polyoxometalate solution at room temperature, and the solution is stirred for ion exchange so that the polyoxometalate is immobilized on the bio-based polyionic liquid to obtain a bio-based green polyionic liquid polyacid desulfurization catalyst.

2. The method for preparing the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 1, characterized in that: The mass ratio of the bio-based polyionic liquid to the polyoxometalate in the polyoxometalate solution is 1:1-5.

3. The method for preparing the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 1, characterized in that: The molar ratio of the gel product to triethanolamine is 1:1-3, the amount of the catalyst used is 0.2 wt.%-0.4 wt.% of the total amount of the gel product, and the catalyst is p-toluenesulfonic acid.

4. The method for preparing the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 1, characterized in that: The temperature of the esterification reaction is 80°C to 120°C, the time is 4 h to 8 h, and the protective gas is nitrogen.

5. The method for preparing the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 1, characterized in that: The molar ratio of the precursor to the alkyl bromide compound is 1:1-3, and the alkyl bromide compound is hexadecane bromide.

6. The method for preparing the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 1, characterized in that: The temperature of the quaternization reaction is 60°C to 150°C, the time is 3 h to 8 h, and the protective gas is nitrogen.

7. The method for preparing the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 1, characterized in that: The sodium alginate solution is an aqueous solution of sodium alginate with a concentration of 0.02 g / mL to 0.08 g / mL. The acidification method is to add hydrochloric acid dropwise to the sodium alginate solution until a gel-state product is generated. The concentration of the hydrochloric acid is 1 M to 3 M. After the gel-state product is generated, it is freeze-dried at -40°C.

8. A bio-based green polyionic liquid polyacid desulfurization catalyst prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the bio-based green polyionic liquid polyacid desulfurization catalyst according to claim 8 in the desulfurization of gasoline and diesel.

10. The use according to claim 9, characterized in that: The polyionic liquid polyacid desulfurization catalyst is used in combination with hydrogen peroxide, which is used as an oxidant. The usage ratio of the polyionic liquid polyacid desulfurization catalyst to gasoline and diesel is 0.05g-0.2g:100ml, and the oxygen-sulfur ratio of hydrogen peroxide to gasoline and diesel is 1:2-9.

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