Preparation method and application of dual-carrier solid superacid
The preparation of dual-carrier solid superacid SO42-/TiO2-ZrO2 by the sol-gel method solves the problems of high raw material consumption and insufficient catalytic performance in the existing technology, and realizes efficient catalytic synthesis of n-amyl acetate and reduces waste liquid discharge.
Patent Information
- Application Number
- CN202511278269.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-09
- Publication Date
- 2025-12-12
AI Technical Summary
Existing methods for preparing superacids suffer from high raw material consumption, high preparation costs, high wastewater treatment costs, and small specific surface area and insufficient catalytic performance of single-support solid superacids.
A dual-support solid superacid SO42-/TiO2-ZrO2 was prepared using the sol-gel method. The sol-gel method allows for the uniform mixing of various chemical components, reducing the use of reagents such as ammonia and deionized water, improving metal utilization, and increasing the specific surface area and catalytic activity of the catalyst.
This method reduces preparation costs, extends catalyst lifespan, improves catalytic performance and specific surface area, reduces waste liquid discharge, and achieves highly efficient catalytic synthesis of n-amyl acetate.
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Figure CN121103392A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the chemical technology field, and in particular to a preparation method and application of a double-carrier solid superacid and an electronic device. BACKGROUND
[0002] SO4 2- / M x O y The formation of the acid center of the solid superacid is mainly due to the SO4 2- The coordination adsorption on the surface of the catalyst makes the electron cloud of the M-O bond shift strongly, and a strong Lewis acid center is generated. When the Lewis acid center adsorbs water molecules, it has a strong attraction to the electrons in the water molecules, so that the water molecules are dissociated and adsorbed to generate a proton acid center. FT-IR studies show that the S=O bond has strong covalent bond characteristics, and its induction effect makes the electron cloud of the M-O bond shift, so that the catalyst exhibits superacidity.
[0003] At present, the solid superacid is mainly prepared by a normal-temperature precipitation impregnation method. The corresponding metal salt is dissolved by using a proper precipitant (such as ammonia, urea, etc.), and is adjusted to a certain pH value to obtain a hydroxide precipitate, which is then washed by deionized water to remove impurity ions, dried, treated by a solution containing SO4 2- , or the amorphous oxide of the corresponding metal is directly treated by a solution containing SO4 2- , and then calcined, that is, the method of first precipitation, then impregnation and then calcination is adopted. In addition to the above method, the gas phase impregnation method, the self-propagating low-temperature combustion method, the low-temperature precipitation aging method and other methods are also used to prepare the superacid.
[0004] However, the existing superacid preparation method still has many defects, which are embodied in that the consumption of raw materials is large in the preparation process, the preparation cost and the wastewater treatment cost are high; and the prepared superacid is a single-carrier superacid, and the single-carrier solid superacid has defects such as small specific surface area and insufficient catalytic performance.
[0005] Based on the above factors, the present application provides a preparation method of a composite solid superacid. SUMMARY
[0006] An advantage of the present application is to provide a preparation method of a double-carrier solid superacid, wherein the sol-gel method is a homogeneous reaction, the reaction time is long, various chemical components are mixed uniformly, and various ions are easy to chemically combine with each other when precipitating, thereby improving the utilization rate of each metal.
[0007] Another advantage of the present application is to provide a preparation method of a double-carrier solid superacid, wherein the composite solid superacid SO4 2-The / TiO2-ZrO2 has high catalytic activity and prolongs the service life.
[0008] Another advantage of the present application is to provide a preparation method of a double-carrier solid superacid, wherein the solid superacid SO4 2- The / TiO2-ZrO2 catalyst has increased specific surface area and good catalytic effect.
[0009] Another advantage of the present application is to provide a preparation method of a double-carrier solid superacid, wherein the use of ammonia and other reagents is reduced during the preparation process by sol-gel method, the use of deionized water is reduced during the washing process, and the discharge of chlorine-containing waste liquid is reduced.
[0010] To achieve at least one of the above advantages or other advantages and objectives, the technical solutions adopted by the present application are as follows: In a first aspect, the present application provides a preparation method of a double-carrier solid superacid, wherein the double-carrier solid superacid is SO4 2- / TiO2-ZrO2; specifically comprising the following steps: S1. Weigh the butyl titanate and dissolve it in an ethanol solvent, and at room temperature, add an acetic acid solution under stirring; S2. Weigh the zirconium n-propyl alcohol in the solution of step S1, adjust the pH, and stir until the reaction mixture is gelled under constant temperature conditions; S3. Soak the gel in step S2 in anhydrous ethanol, wash the gel, dry and grind the gel to obtain gel powder; soak the gel powder, filter, dry the filter cake, and grind to obtain a solid powder; S4. Soak the solid powder in step S3 in an H2SO4 solution, then filter, dry the filter cake, and grind and calcine at high temperature to obtain a solid superacid SO4 2- / TiO2-ZrO2.
[0011] In the preparation method of the double-carrier solid superacid according to the present application, the constant temperature condition in step S2 is a 70-90℃ constant temperature water bath.
[0012] In the preparation method of the double-carrier solid superacid according to the present application, the atomic ratio of Zr / Ti in step S1 and step S2 is 0.15-0.25.
[0013] In the preparation method of the double-carrier solid superacid according to the present application, the concentration of the H2SO4 soaking solution in step S4 is 0.5-1.5 mol / L.
[0014] In the preparation method of the double-carrier solid superacid according to the present application, the calcination temperature in step S4 is 450-550℃, and the calcination time is 2-6h.
[0015] In the preparation method of the double-carrier solid superacid SO4 2- The acid strength H0 of the / TiO2-ZrO2 is less than or equal to (10.00-15.00).
[0016] In the preparation method of the double-carrier solid superacid SO4
[0017] In the preparation method of the double-carrier solid superacid SO4
[0018] In the preparation method of the double-carrier solid superacid SO4
[0019] In the preparation method of the double-carrier solid superacid SO4
[0020] In the preparation method of the double-carrier solid superacid SO4
[0021] Further objects and advantages will become apparent from a consideration of the drawings and the ensuing description.
[0022] These and other objects, features and advantages of the present application will become apparent with reference to the following detailed description of the application taken in combination with the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS
[0023] These and / or other aspects and advantages of the present application will become apparent and more readily appreciated from the following detailed description, taken in conjunction with the accompanying drawings, in which: Figure 1 The composite carrier solid superacid SO4 2- Orthogonal experiment of the / TiO2-ZrO2 catalyst prepared by the sol-gel method for catalyzing synthesis of n-pentyl acetate Figure 2 The composite carrier solid superacid SO4 2- Orthogonal experiment of the / TiO2-ZrO2 catalyst prepared by the sol-gel method for catalyzing synthesis of n-pentyl acetate
[0024] Figure 3 The XRD spectrum of the SO4 2- / ZrO2-TiO2 catalyst sample.
[0025] Figure 4 The TEM image of the SO4 2- / ZrO2-TiO2 sample before reaction.
[0026] Figure 5 SO4 2- TEM image of ZrO2-TiO2 sample. DETAILED DESCRIPTION
[0027] The application will be described in further detail below with reference to the drawings and specific embodiments.
[0028] Example 1 SO4 2- / TiO2-ZrO2; S1. Butyl titanate was weighed and dissolved in ethanol solvent, and placed in a constant temperature water bath for stirring to dissolve. After stirring for 20 min, glacial acetic acid was added dropwise at room temperature and under stirring for 20 min, and then deionized water was added dropwise while continuing to stir; S2. Zirconium n-propyl alcohol was added dropwise to the solution in step 1 and stirred for 10 min, and then deionized water was added and the pH value was adjusted with glacial acetic acid. Then the reaction mixture was placed in a constant temperature water bath for gelation by refluxing, and the reaction temperature was maintained at 80°C during the refluxing process, and the solution was stirred until it became a transparent colorless gel, S3. The gel in step S2 was crushed and aged, and after aging, it was first soaked with anhydrous ethanol, and then washed with distilled water. The washed gel was placed in an oven and dried at 70°C for 12 h, then soaked with distilled water, suction filtered, washed thoroughly, and then dried at 110°C for 12 h, ground, and passed through a 120 mesh experimental sieve to obtain gel powder; S4. After impregnation with an H2SO4 solution, suction filtration was performed under reduced pressure, the filter cake was dried in an infrared rapid dryer for about 6 h, and then ground and calcined at a certain temperature in a muffle furnace for 4 h to obtain solid superacid SO4 2- / TiO2-ZrO2.
[0029] Probe reaction The esterification reaction of acetic acid and n-pentanol to synthesize n-pentyl acetate was used as a probe reaction, and the catalytic activity of the catalyst was investigated by using the esterification rate. The reaction was refluxed at 110-120°C for 1.0 h, and the esterification rate of the reaction was determined.
[0030] Effect of Zr / Ti atomic ratio on catalytic activity The concentration of the H2SO4 impregnation solution was fixed at 0.5 mol / L, the calcination temperature was 550°C, the ratio between the amounts of zirconium n-propyl alcohol and butyl titanate was changed, and the effect of the Zr / Ti atomic ratio on the catalytic activity was investigated by using the probe reaction:
[0031] As shown in Table 1, the atomic ratio of Zr / Ti has an effect on the catalytic activity, and the esterification rate is the highest when n(Zr) / n(Ti)=0.2, indicating that the optimal atomic ratio of Zr / Ti is 0.2.
[0032] Effect of H2SO4 solution concentration on catalytic activity When n(Zr) / n(Ti)=0.2 and the calcination temperature is 550℃, the concentration of the H2SO4 impregnation solution is changed, and the effect of the impregnation solution concentration on the catalytic activity is investigated by using the probe reaction:
[0033] As shown in Table 2, the H2SO4 solution concentration has a greater effect on the catalytic activity, and the catalytic activity will decrease when the concentration is too small or too large. When the concentration is in the range of 0.5-1.5 mol / L, the impregnated catalyst has a relatively high catalytic activity, and the catalytic activity of the catalyst is the highest when the concentration of the H2SO4 impregnation solution is 1.0 mol / L.
[0034] Effect of calcination temperature on catalytic activity When n(Zr) / n(Ti)=0.2 and the concentration of the H2SO4 impregnation solution is 1.0 mol / L, the calcination temperature of the catalyst is changed, and the effect of the calcination temperature on the catalytic activity is investigated by using the probe reaction:
[0035] As shown in Table 3, the calcination temperature has a greater effect on the catalytic activity, and the catalytic activity will decrease when the calcination temperature is too high or too low. The catalyst calcined at 500-600℃ has a relatively high catalytic activity, and the catalytic activity of the catalyst is the highest when the calcination temperature is 500℃.
[0036] Based on the above experimental analysis results, it can be determined that the optimal preparation conditions of the composite carrier solid superacid SO4 2- / TiO2-ZrO2 catalyst prepared by the sol-gel method are as follows: the atomic ratio of Zr / Ti is 0.2; the concentration of the H2SO4 impregnation solution is 1.0 mol / L; and the calcination temperature is 500℃.
[0037] Example 2 Orthogonal test of the synthesis of n-pentyl acetate catalyzed by the composite carrier solid superacid SO4 2- / TiO2-ZrO2 catalyst prepared by the sol-gel method (1) Orthogonal design In order to comprehensively consider the effects of reaction time, catalyst dosage and alcohol-acid molar ratio on the synthesis of n-pentyl acetate, according to the single-factor experiment, the orthogonal test is determined according to the factors and levels, and the L9(33) orthogonal table is used. The solid superacid SO4 2- / TiO2-ZrO2 catalyzed synthesis of n-pentyl acetate, factor level see Table 4:
[0038] Note: glacial acetic acid dosage is 0.20 mol, reaction temperature is 110-118℃.
[0039] According to the orthogonal test scheme, 9 experiments were carried out, the experimental results were evaluated, and then orthogonal experiment analysis was carried out; the experimental results are shown in Table 5: Table 5-orthogonal test results and analysis (L9(33))
[0040] (2) Experimental data processing Intuitive analysis is used for data processing: Range RA=5.6, RB=6.0, RC=4.1, then RB> RA> RC, the primary and secondary order of the factors is B>A>C, that is, the amount of catalyst> reaction time> alcohol acid molar ratio.
[0041] Compare the J values of each column, the larger the J value, the more significant the level on the experimental results.
[0042] Factor A: J2 >J1>J3, level 2 of factor A is the best, which shows that the reaction time should be moderate, too short or too long is not conducive to the improvement of esterification reaction yield.
[0043] Factor B: J3>J2>J1, level 3 of factor B is the best, which shows that a larger amount of catalyst is beneficial to the esterification reaction.
[0044] Factor C: J2>J3>J1, level 2 of factor C is the best, which shows that the alcohol acid molar ratio should be moderate, too small or too large is not conducive to the improvement of esterification reaction yield.
[0045] Through Figure 1 Intuitive analysis of orthogonal intuitive analysis can get the optimal conditions for the synthesis of n-pentyl acetate as follows: reaction time 2.5h, catalyst dosage 0.5g (4.2% of the mass of acetic acid), alcohol acid molar ratio 1.3:1.
[0046] (3) Parallel experiment of the optimal group Fix the reaction time at 2.5h, the catalyst dosage at 0.5g, and the alcohol acid molar ratio at 1.3:1 (acetic acid dosage 0.20 mol, n-pentanol dosage 0.26 mol), and the reaction temperature at 110-118℃. Under the above reaction conditions, 3 parallel synthesis experiments were carried out to investigate the reliability and reproducibility of the experimental results. The experimental results are shown in Table 6:
[0047] Table 6-parallel experiment results
[0048] From Table 6, it can be seen that the yield of n-pentyl acetate synthesized under the optimal conditions is stable, the repeatability is good, and the experimental results are reliable. The average yield of three parallel experiments can reach 90.1%.
[0049] Example 3 The composite carrier solid superacid SO4 2- / TiO2-ZrO2 catalyst under microwave irradiation to catalytically synthesize n-pentyl acetate In order to comprehensively consider the effects of alcohol-acid molar ratio, reaction temperature, reaction time and catalyst dosage on the synthesis of n-pentyl acetate under microwave irradiation, on the basis of the results of the above single-factor experiments, four suitable levels in each factor were determined for orthogonal experiment. L16(44) orthogonal table was used, and the factor levels are shown in Table 7:
[0050] Table 7 - Factor and level table for microwave irradiation catalytic synthesis of n-pentyl acetate experiment
[0051] Note: The alcohol-acid ratio is the molar ratio, and the amount of glacial acetic acid is 0.20 mol.
[0052] According to the orthogonal experiment scheme, 16 experiments were carried out, and the experimental results were evaluated. Then, orthogonal experiment analysis was carried out. The experimental results are shown in Table 8:
[0053] (2) Experimental results and data processing Data processing was carried out by visual analysis: Range RA=13.8, RB=14.9, RC=16.1, RD=8.1, then RC> RB> RA> RD, the primary and secondary order of factors is C>B>A>D, i.e. reaction time > reaction temperature > alcohol-acid molar ratio > catalyst dosage.
[0054] Compare the J values of each column. The larger the J value, the more significant the level on the experimental results.
[0055] Factor A: J2 > J3 > J1 > J4, level 2 of factor A is the best, which indicates that the alcohol-acid molar ratio should be moderate, and too small or too large is not conducive to the improvement of esterification reaction yield.
[0056] Factor B: J3 > J2 > J1 > J4, level 3 of factor B is the best, which indicates that a higher reaction temperature is beneficial to the esterification reaction.
[0057] Factor C: J3 > J4 > J2 > J1, level 3 of factor C is the best, which indicates that a longer reaction time is beneficial to the improvement of esterification reaction yield.
[0058] Factor D: J3> J2> J4> J1, the level 3 of factor D is the best, which indicates that the catalyst dosage should be moderate, too small or too large is not conducive to the improvement of the yield of esterification reaction.
[0059] After Figure 2 Orthogonal direct analysis can know that under microwave irradiation, SO4 2- / TiO2-ZrO2 catalytic synthesis of n-pentyl acetate optimal synthesis conditions for alcohol acid molar ratio 1.5:1, reaction temperature 135℃, reaction time 50min, catalyst dosage 0.5g (4.2% of the mass of the raw material acetic acid).
[0060] (3) the optimal group parallel experiment Set the microwave power 500W, reaction temperature 135℃, reaction time 50min, fixed alcohol acid molar ratio 1.5:1 (acetic acid dosage 0.20mol, n-pentanol dosage 0.30mol), catalyst dosage 0.5g. Under the above reaction conditions, 3 times of the same parallel synthesis experiment, to investigate the reliability and reproducibility of experimental results. The experimental results are shown in table 9:
[0061] From table 9, under microwave irradiation, SO4 2- / TiO2-ZrO2 catalytic synthesis of n-pentyl acetate yield stability, good reproducibility, reliable experimental results. The average ester yield of three groups of parallel experiments can reach 96.6%.
[0062] SO4 2- / TiO2-ZrO2 characterization results analysis (1) acid strength Hammett indicator method determination results show that, according to the best preparation conditions of SO4 2- / TiO2-ZrO2 catalyst sample can make Hammett indicator m-nitrochlorobenzene solution to acid type color, which shows that the acid strength of the catalyst sample H0≤-13.16, which proves that the SO4 2- / TiO2-ZrO2 catalyst prepared in this experiment is a solid super acid.
[0063] (2) specific surface area BET method determination results show that, according to the best preparation conditions of SO4 2- / TiO2-ZrO2 catalyst sample specific surface area is 46.2m 2 / g, which shows that although the composite carrier solid super acid SO4 2- / TiO2-ZrO2 prepared by precipitation-impregnation method has good catalytic activity, but its surface area is not very large.
[0064] (3) XRD analysis FromFigure 3 The XRD spectrum of the sample shows that obvious diffraction peaks appear at 2Θ of 25.28°, 48.05°, 37.80°, 53.89°, 55.06°, etc. The JCPDS card database is searched for the corresponding card, and it is found that the standard diffraction data of anatase TiO2 with JCPDS card number 21-1272 are the same as the diffraction peak position and relative intensity in the diffraction spectrum, so it can be determined that the TiO2 in the SO4 2- / TiO2-ZrO2 sample is in an anatase crystal phase.
[0065] At the same time, almost no crystal phase diffraction peak of ZrO2 is observed, and the result is analyzed as follows: the crystallization process is inhibited due to the strong interaction between TiO2 and ZrO2, and the composite oxide formed by ZrO2 and TiO2 exists in an amorphous state after calcination at 500°C.
[0066] (4) TEM analysis In order to investigate the influence of the reaction on the morphology of the solid superacid catalyst, the SO4 2- / TiO2-ZrO2 catalyst samples before and after the synthesis reaction of n-pentyl acetate under microwave irradiation were subjected to TEM analysis. The results are shown in Figure 4 and Figure 5 . By comparing Figure 4 and Figure 5 , it can be seen that the morphology of the catalyst before and after the reaction has changed greatly. The SO4 2- / TiO2-ZrO2 sample before the reaction is distributed loosely and has a relatively uniform network structure with obvious cavities; the SO4 2- / TiO2-ZrO2 sample after the reaction is distributed densely and appears to be clustered, which is due to the sintering and carbon deposition of the catalyst after the reaction.
[0067] It should be noted that in the device and method of the present application, each component or each step in different embodiments can be decomposed and / or recombined without departing from the principles of the present application. These decompositions and / or recombination should be considered to be within the inventive concept of the present application.
[0068] The basic principles of the present application are described above in combination with specific embodiments, but it should be noted that the advantages, advantages, effects, etc. mentioned in the present application are only examples and are not limiting, and these advantages, advantages, effects, etc. cannot be considered as the must-have of each embodiment of the present application. In addition, the above specific details are only for the purpose of example and for the purpose of understanding, and are not limiting, and the above details do not limit the present application to the must-use specific details.
Claims
1. A method for preparing a dual-support solid superacid, characterized in that, The double-support solid super acid is SO4 2- / TiO2-ZrO2; comprising the following steps: S1. Butyl titanate is weighed and dissolved in ethanol solvent, and acetic acid solution is added under stirring at room temperature; S2. Zirconium n-propyl alcohol is weighed and added to the solution in step S1, the pH is adjusted, and the reaction mixture is gelled under constant temperature conditions under stirring; S3. The gel in step S2 is soaked in anhydrous ethanol, the gel is washed, and the gel is dried and ground to obtain a gel powder; the gel powder is soaked, suction filtered, the filter cake is dried, and ground to obtain a solid powder; S4. The solid powder in step S3 is impregnated in H2SO4 solution, then suction filtration is performed, the filter cake is dried, ground and crushed, and then calcined at high temperature to obtain a solid superacid SO4 2- / TiO2-ZrO2.
2. The preparation method of the double-carrier solid super acid according to claim 1, characterized in that, The constant temperature condition in step S2 is a 70-90℃ constant temperature water bath.
3. The method for preparing a double-support solid super acid according to claim 1, characterized in that, The atomic ratio of Zr / Ti in step S1 and step S2 is 0.15-0.
25.
4. The method for preparing a dual-support solid super acid according to claim 1, characterized in that, The concentration of the H2SO4 impregnation solution in step S4 is 0.5-1.5 mol / L.
5. The method for preparing a double-support solid super acid according to claim 3, characterized in that, The calcination temperature in step S4 is 450-550℃, and the calcination time is 2-6h.
6. The method for preparing a double-support solid super acid according to claim 3, characterized in that, The solid super acid SO4 2- The acid strength H0 of / TiO2-ZrO2 is ≤ (10.00~15.00).
7. The method for preparing a dual-carrier solid superacid according to claim 1, characterized in that, The constant temperature heating temperature in step S2 is 70-90℃.
8. The method for preparing a dual-carrier solid superacid according to claim 1, characterized in that, The gel powder in step S3 is dried at 110℃ for 12h after washing.
9. A solid superacid catalyst prepared by the method of any one of claims 1-6.
10. Use of the solid superacid catalyst of claim 7 for catalyzing the synthesis of n-pentyl acetate.