A process for the preparation of cyclopentanol from cyclopentene

Abstract

This invention belongs to the field of cyclopentanol preparation technology. This invention provides a method for preparing cyclopentanol from cyclopentene, comprising the following steps: S1, in a high-pressure reactor, a tin oxide / zirconium-alumina solid acid catalyst is loaded into a basket, and cyclopentene, deionized water, and solvent are pumped into the reactor using a peristaltic pump. The high-pressure reactor is then sealed. The molar ratio of cyclopentene to deionized water is (5.8-6.2):1, the mass of the solvent is equal to the mass of cyclopentene, and the mass of the tin oxide / zirconium-alumina solid acid catalyst is 24-26% of the mass of deionized water. S2, after pressurizing and leak testing to ensure good reaction sealing, the temperature is lowered to 5-10℃, and the reactor is purged three times with nitrogen to ensure complete removal of air. The pressure is then increased to 0.5 MPa with nitrogen, stirred, and heated to 130±2℃. After reacting for 4 hours, the mixture is cooled to 10±2℃, discharged, and centrifuged. This invention effectively improves the catalytic activity of the catalyst, thereby increasing the selectivity of cyclopentanol, while also improving the catalyst's regeneration capacity.

Description

Technical Field

[0001] This invention belongs to the field of cyclopentanol preparation technology, and in particular relates to a method for preparing cyclopentanol from cyclopentene. Background Technology

[0002] Cyclopentanol is a colorless, viscous liquid with an aromatic odor. It is an important intermediate in pharmaceutical and pesticide fine chemical products, mainly used in the preparation of bromocyclopentane, chlorocyclopentane, antibacterial drugs, and anti-allergy drugs. Currently, cyclopentanol is mainly produced from adipic acid as a raw material, which undergoes high-temperature decarboxylation to obtain cyclopentanone, followed by hydrogenation. However, the large amount of pollutants generated by the reaction and the limitation of raw material sources restrict the further development of this process. In recent years, due to the abundant and inexpensive resources of C5 fraction, research on the production of cyclopentanol from C5 fraction has received widespread attention both domestically and internationally. C5 fraction is a byproduct of naphtha steam cracking to produce ethylene. The dicyclopentadiene fraction can be depolymerized and selectively hydrogenated to produce cyclopentene. Cyclopentanol is then prepared from cyclopentene.

[0003] The reaction of cyclopentene with water to prepare cyclopentanol is an electrophilic addition reaction. When cyclopentene is adsorbed on the catalyst surface, it forms a carbocation under the influence of the catalyst's acidic centers. The carbocation then reacts with water to form cyclopentanol. Different acidic catalysts provide different types and strengths of acidic centers, which have varying effects on the reaction. Therefore, improving and developing catalysts has always been a core research topic in this field. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a method for preparing cyclopentanol from cyclopentene, which effectively improves the catalytic activity of the catalyst, thereby enhancing the selectivity of cyclopentanol while also improving the catalyst's regeneration capacity.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing cyclopentanol from cyclopentene includes the following steps: S1. In a high-pressure reactor, the tin oxide / zirconium-alumina solid acid catalyst is loaded into a basket, and cyclopentene, deionized water and solvent are pumped into the reactor using a peristaltic pump. The high-pressure reactor is then sealed. The molar ratio of cyclopentene to deionized water is (5.8-6.2):1, the mass of the solvent is equal to the mass of cyclopentene, and the mass of the tin oxide / zirconium-alumina solid acid catalyst is 24-26% of the mass of deionized water. S2. After pressurizing and leak testing to ensure good sealing of the reaction, cool down to 5-10℃, purge with nitrogen three times to ensure complete removal of air from the reactor, pressurize with nitrogen to 0.5MPa, stir and heat to 130±2℃, react for 4 hours, cool to 10±2℃, discharge, centrifuge, and analyze the reactants.

[0006] Furthermore, the preparation method of the tin oxide / zirconium-alumina solid acid catalyst is as follows: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to n(tin):n(zirconium):n(aluminum) = 8.8:(0.3-0.5):1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5%-5.3%. A2. While stirring the base solution, ammonia water is added dropwise to adjust the pH value to 8. The solution is allowed to stand at room temperature until precipitation is complete. Then, it is aged at 5-10℃ for 12-14 hours, filtered, and the filter cake is washed with ammonium acetate solution until the pH value is 7 and dried to obtain the precursor. A3. Prepare a sulfuric acid-ammonium sulfate impregnation solution, which includes 3.0 mol / L sulfuric acid and 0.2-0.3 mol / L ammonium sulfate; A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with the sulfuric acid-ammonium sulfate impregnation solution for 1-1.2 hours, filter it, dry it, and calcine it at 515-520°C for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0007] Furthermore, in A2, the stirring speed is 450-500 rpm, and the mass fraction of ammonia water is 25%-28%.

[0008] Furthermore, in A2, the mass fraction of ammonium acetate solution is 3.8%-4.2%.

[0009] Furthermore, in A3, the ratio of sulfuric acid-ammonium sulfate impregnation solution to precursor is (14.5-15.5) mL: 1 g.

[0010] Furthermore, in both A2 and A3, the drying temperature is 108-112℃ and the drying time is 11.5-12.5h.

[0011] Furthermore, in S1, the solvent is phenol.

[0012] Furthermore, in S2, the specific procedure for pressurizing and leak testing is as follows: pressurize with nitrogen to 4±0.2MPa and test for leaks for 30 minutes.

[0013] Furthermore, in S2, the stirring speed is 580-600 rpm.

[0014] Compared with the prior art, the present invention has the following beneficial effects: In the preparation of cyclopentene from cyclopentene using a tin oxide / zirconium-alumina solid acid catalyst, the ionic S=O bond can be converted into a covalent bond during high-temperature calcination. The inductive effect of this covalent bond causes the metal ion Sn to... 4+It possesses a strong electron-withdrawing ability, which makes it extremely acidic; zirconium nitrate (Zr) is added / doped into the base solution. 4+ Entering the SnO2 lattice, it distorts the lattice symmetry, generating a lattice stress field, further strengthening Sn. 4+ The electron-withdrawing ability of the catalyst enhances its catalytic activity.

[0015] In the preparation of tin oxide / zirconium-alumina solid acid catalysts, ammonium sulfate is added / introduced to obtain a sulfuric acid-ammonium sulfate impregnation solution. Ammonium sulfate, as a slow-release sulfur source, can better provide supplementary sulfur species in the early stage of higher-temperature calcination, and better compensate for decomposition losses at high temperatures. At the same time, ammonium ions can intercalate into the precursor, expand the interlayer spacing, facilitate the embedding of sulfur species, and facilitate regeneration. Thus, the catalyst's catalytic activity and regeneration capacity are synergistically enhanced at higher temperatures. Attached Figure Description

[0016] Figure 1 This is a comparative trend chart of the initial cyclopentanol selectivity and the cyclopentanol selectivity after regeneration for Examples 1-3 and Comparative Examples 1-4 in the experimental examples of this invention; Figure 2 This is a comparative trend chart of the selectivity retention rate data of Examples 1-3 and Comparative Examples 1-4 in the experimental examples of this invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1

[0019] (I) Preparation of tin oxide / zirconium-alumina solid acid catalyst, the preparation method is as follows: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.4:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5.2%.

[0020] A2. While stirring the base solution at a stirring speed of 480 rpm, add 26% ammonia water dropwise to adjust the pH value to 8. Let it stand at room temperature until precipitation is complete, then age it at a low temperature of about 8℃ for 13 hours, filter it, wash the filter cake with 4.0% ammonium acetate solution until the pH value is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0021] A3. Prepare a sulfuric acid-ammonium sulfate impregnation solution, which includes 3.0 mol / L sulfuric acid and 0.25 mol / L ammonium sulfate.

[0022] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with a sulfuric acid-ammonium sulfate impregnation solution for 1.1 hours. The ratio of sulfuric acid-ammonium sulfate impregnation solution to precursor is 15 mL: 1 g. Then filter it, dry it at 110 °C for 12 hours, and then calcine it at 517 °C for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0023] (ii) A method for preparing cyclopentanol from cyclopentene, comprising the following steps: S1. In a high-pressure reactor, the tin oxide / zirconium-alumina solid acid catalyst is loaded into a basket, and cyclopentene, deionized water and solvent phenol are pumped into the reactor using a peristaltic pump. The high-pressure reactor is then sealed.

[0024] The molar ratio of cyclopentene to deionized water is 6.0:1, the mass of the solvent is equal to the mass of cyclopentene, and the mass of the tin oxide / zirconium-alumina solid acid catalyst is 25% of the mass of deionized water. S2. Pressurize with nitrogen to 4 MPa, test for leaks for 30 minutes to ensure good reaction sealing, then cool to about 8°C, purge with nitrogen three times to ensure complete removal of air from the reactor, pressurize with nitrogen to 0.5 MPa, stir at 590 rpm and heat to 130°C, react for 4 hours, cool to 10°C, discharge, centrifuge, and analyze the reactants.

[0025] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this embodiment is as follows: the deactivated catalyst is calcined in a muffle furnace at 517°C for 2 hours, then impregnated with the sulfuric acid-ammonium sulfate impregnation solution of this embodiment at a standard concentration of 15 mL / g, dried, and then calcined in a muffle furnace at 517°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0026] Example 2

[0027] The difference between this embodiment and Example 1 is that the tin oxide / zirconium-alumina solid acid catalyst is prepared by the following method: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.3:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5.3%.

[0028] A2. While stirring the base solution at 450 rpm, add 25% ammonia water dropwise to adjust the pH to 8. Let it stand at room temperature until precipitation is complete, then age it at about 8℃ for 13 hours. Filter the solution, wash the filter cake with 3.8% ammonium acetate solution until the pH is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0029] A3. Prepare a sulfuric acid-ammonium sulfate impregnation solution, which includes 3.0 mol / L sulfuric acid and 0.2 mol / L ammonium sulfate.

[0030] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with a sulfuric acid-ammonium sulfate impregnation solution for 1.2 hours. The ratio of sulfuric acid-ammonium sulfate impregnation solution to precursor is 15.5 mL: 1 g. Then filter it, dry it at 110 °C for 12 hours, and then calcine it at 515 °C for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0031] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this embodiment is as follows: the deactivated catalyst is calcined in a muffle furnace at 515°C for 2 hours, then impregnated with the sulfuric acid-ammonium sulfate impregnation solution of this embodiment at a standard concentration of 15.5 mL / g, dried, and then calcined in a muffle furnace at 515°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0032] Example 3

[0033] The difference between this embodiment and Example 1 is that the tin oxide / zirconium-alumina solid acid catalyst is prepared by the following method: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.5:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5%.

[0034] A2. While stirring the base solution at 500 rpm, add 28% ammonia water dropwise to adjust the pH value to 8. Let it stand at room temperature until precipitation is complete, then age it at about 8℃ for 13 hours. Filter the solution, wash the filter cake with 4.2% ammonium acetate solution until the pH value is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0035] A3. Prepare a sulfuric acid-ammonium sulfate impregnation solution, which includes 3.0 mol / L sulfuric acid and 0.3 mol / L ammonium sulfate.

[0036] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with a sulfuric acid-ammonium sulfate impregnation solution for 1 hour. The ratio of sulfuric acid-ammonium sulfate impregnation solution to precursor is 14.5 mL: 1 g. Then filter it, dry it at 110 °C for 12 hours, and then calcine it at 520 °C for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0037] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this embodiment is as follows: the deactivated catalyst is calcined in a muffle furnace at 520°C for 2 hours, then impregnated with the sulfuric acid-ammonium sulfate impregnation solution of this embodiment at a standard concentration of 14.5 mL / g, dried, and then calcined in a muffle furnace at 520°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0038] Comparative Example 1 The difference between this comparative example and Example 1 is that in the preparation of the tin oxide / zirconium-alumina solid acid catalyst, the sulfuric acid-ammonium sulfate impregnation solution is replaced with a sulfuric acid impregnation solution (i.e., no ammonium sulfate is added), and the calcination temperature is 485°C.

[0039] Specifically, the tin oxide / zirconium-alumina solid acid catalyst is prepared by the following method: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.4:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5.2%.

[0040] A2. While stirring the base solution at a stirring speed of 480 rpm, add 26% ammonia water dropwise to adjust the pH value to 8. Let it stand at room temperature until precipitation is complete, then age it at a low temperature of about 8℃ for 13 hours, filter it, wash the filter cake with 4.0% ammonium acetate solution until the pH value is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0041] A3. Prepare a sulfuric acid impregnation solution, which includes 3.0 mol / L sulfuric acid.

[0042] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with sulfuric acid impregnation solution for 1.1 h. The ratio of sulfuric acid impregnation solution to precursor is 15 mL: 1 g. Then filter it, dry it at 110 °C for 12 h, and then calcine it at 485 °C for 2 h to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0043] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this comparative example is as follows: the deactivated catalyst is calcined in a muffle furnace at 485°C for 2 hours, then impregnated with the comparative example sulfuric acid impregnation solution at 15 mL / g, dried, and calcined in a muffle furnace at 485°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0044] Comparative Example 2 The difference between this comparative example and Example 1 is that in the preparation of the tin oxide / zirconium-alumina solid acid catalyst, the sulfuric acid-ammonium sulfate impregnation solution is replaced with a sulfuric acid impregnation solution (i.e., no ammonium sulfate is added), and the calcination temperature is 500°C.

[0045] Specifically, the tin oxide / zirconium-alumina solid acid catalyst is prepared by the following method: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.4:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5.2%.

[0046] A2. While stirring the base solution at a stirring speed of 480 rpm, add 26% ammonia water dropwise to adjust the pH value to 8. Let it stand at room temperature until precipitation is complete, then age it at a low temperature of about 8℃ for 13 hours, filter it, wash the filter cake with 4.0% ammonium acetate solution until the pH value is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0047] A3. Prepare a sulfuric acid impregnation solution, which includes 3.0 mol / L sulfuric acid.

[0048] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with sulfuric acid impregnation solution for 1.1 hours. The ratio of sulfuric acid impregnation solution to precursor is 15 mL: 1 g. Then filter it, dry it at 110℃ for 12 hours, and then calcine it at 500℃ for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0049] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this comparative example is as follows: the deactivated catalyst is calcined in a muffle furnace at 500°C for 2 hours, then impregnated with the comparative example sulfuric acid impregnation solution at 15 mL / g, dried, and then calcined in a muffle furnace at 500°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0050] Comparative Example 3 The difference between this comparative example and Example 1 is that in the preparation of the tin oxide / zirconium-alumina solid acid catalyst, the sulfuric acid-ammonium sulfate impregnation solution is replaced with a sulfuric acid impregnation solution (i.e., no ammonium sulfate is added), and the calcination temperature is 517°C.

[0051] Specifically, the tin oxide / zirconium-alumina solid acid catalyst is prepared by the following method: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.4:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5.2%.

[0052] A2. While stirring the base solution at a stirring speed of 480 rpm, add 26% ammonia water dropwise to adjust the pH value to 8. Let it stand at room temperature until precipitation is complete, then age it at a low temperature of about 8℃ for 13 hours, filter it, wash the filter cake with 4.0% ammonium acetate solution until the pH value is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0053] A3. Prepare a sulfuric acid impregnation solution, which includes 3.0 mol / L sulfuric acid.

[0054] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with sulfuric acid impregnation solution for 1.1 hours. The ratio of sulfuric acid impregnation solution to precursor is 15 mL: 1 g. Then filter it, dry it at 110 °C for 12 hours, and then calcine it at 517 °C for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0055] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this comparative example is as follows: the deactivated catalyst is calcined in a muffle furnace at 517°C for 2 hours, then impregnated with the comparative example sulfuric acid impregnation solution at 15 mL / g, dried, and then calcined in a muffle furnace at 517°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0056] Comparative Example 4 The difference between this comparative example and Example 1 is that the calcination temperature in the preparation of the tin oxide / zirconium-alumina solid acid catalyst is 500°C.

[0057] Specifically, the tin oxide / zirconium-alumina solid acid catalyst is prepared by the following method: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to the ratio of n(tin):n(zirconium):n(aluminum) = 8.8:0.4:1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5.2%.

[0058] A2. While stirring the base solution at a stirring speed of 480 rpm, add 26% ammonia water dropwise to adjust the pH value to 8. Let it stand at room temperature until precipitation is complete, then age it at a low temperature of about 8℃ for 13 hours, filter it, wash the filter cake with 4.0% ammonium acetate solution until the pH value is 7, and dry it at 110℃ for 12 hours to obtain the precursor.

[0059] A3. Prepare a sulfuric acid-ammonium sulfate impregnation solution, which includes 3.0 mol / L sulfuric acid and 0.25 mol / L ammonium sulfate.

[0060] A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with a sulfuric acid-ammonium sulfate impregnation solution for 1.1 hours. The ratio of sulfuric acid-ammonium sulfate impregnation solution to precursor is 15 mL: 1 g. Then filter it, dry it at 110°C for 12 hours, and then calcine it at 500°C for 2 hours to obtain the tin oxide / zirconium-alumina solid acid catalyst.

[0061] The regeneration method of the tin oxide / zirconium-alumina solid acid catalyst in this comparative example is as follows: the deactivated catalyst is calcined in a muffle furnace at 500°C for 2 hours, then impregnated with the comparative example sulfuric acid-ammonium sulfate impregnation solution at 15 mL / g, dried, and then calcined in a muffle furnace at 500°C for 2 hours; the tin oxide / zirconium-alumina solid acid catalyst regenerated by the above method is then used in the reaction of cyclopentene hydration to prepare cyclopentanol.

[0062] Test case Test subjects: reactant samples prepared in Examples 1-3 and Comparative Examples 1-4.

[0063] Test items: ① Catalytic activity: Cyclopentanol selectivity (%) = mass of cyclopentene converted to cyclopentanol / mass of cyclopentene converted × 100%; where, the mass of cyclopentene converted = (mass of cyclopentene in the feed - mass of cyclopentene in the reaction solution); the higher the cyclopentanol selectivity value, the higher the catalytic activity of the corresponding catalyst. ② Catalyst regeneration capacity: After 10 uses, regeneration is performed; selectivity retention rate (%) = cyclopentanol selectivity after regeneration / initial cyclopentanol selectivity × 100%; the higher the selectivity retention rate value, the stronger the catalyst regeneration capacity.

[0064] Experimental results: see Table 1.

[0065] Table 1. Experimental data in the experimental examples Results Analysis: Combining the data in Table 1 and... Figures 1-2Analysis of Examples 1-3 shows that the initial cyclopentanol selectivity of the present invention (Examples 1-3) is as high as 96.8% or more. After the catalyst is used 10 times and regenerated, the cyclopentanol selectivity after regeneration is as high as 93.5% or more, and the selectivity retention rate is as high as 96.6% or more.

[0066] Combining the data in Table 1 and Figures 1-2 Analysis of Example 1 and Comparative Examples 1-4, specifically comparing Comparative Examples 1, 2 and 3, shows that the initial cyclopentanol selectivity of 91.5% (Comparative Example 1) at a calcination temperature of 485℃ and 92.0% (Comparative Example 3) at a calcination temperature of 517℃ are significantly lower than the initial cyclopentanol selectivity of 93.6% (Comparative Example 2) at a calcination temperature of 500℃.

[0067] This is mainly because 500℃ is the optimal calcination temperature; calcination temperatures below 500℃ are too low, failing to form a sufficient number of superacid centers, resulting in a low number of active catalyst sites and consequently low catalytic activity; while calcination temperatures above 500℃ become too high, leading to insufficient formation of SO42- bound to the catalyst surface. 2- to SO x The decomposition and loss of sulfur in the form of catalyst leads to a decrease in sulfur content, collapse of catalyst structure, and consequently a decrease in catalyst activity.

[0068] Specifically, comparing Comparative Examples 2 and 4, it can be seen that when the calcination temperature is 500℃, compared to Comparative Example 2, the addition / introduction of ammonium sulfate in the impregnation solution during catalyst preparation in Comparative Example 4 resulted in an increase in the initial cyclopentanol selectivity from 93.6% (Comparative Example 2) to 96.1% (Comparative Example 4). After 10 uses and regeneration, the selectivity retention rate increased from 94.9% (Comparative Example 2) to 95.9% (Comparative Example 4). This indicates that adding / introducing ammonium sulfate into the impregnation solution can improve the catalytic activity and regeneration capacity of the prepared catalyst.

[0069] In a specific comparison with Comparative Example 3 and Example 1, it can be seen that when the calcination temperature is 517°C, compared with Comparative Example 3, the addition / introduction of ammonium sulfate in the impregnation solution during catalyst preparation in Example 1 resulted in an increase in the initial cyclopentanol selectivity from 92.0% (Comparative Example 3) to 97.4% (Example 1), which is significantly greater than 96.1% (Comparative Example 4). After the catalyst was regenerated after 10 uses, the selectivity retention rate increased from 94.6% (Comparative Example 3) to 96.8% (Example 1), which is significantly greater than 95.9% (Comparative Example 4). This indicates that compared with a calcination temperature of 500°C, the addition / introduction of ammonium sulfate in the impregnation solution can have a synergistic effect with a higher calcination temperature (517°C), synergistically improving the catalytic activity and regeneration capacity of the prepared catalyst.

[0070] This is mainly because by adding / introducing ammonium sulfate, a sulfuric acid-ammonium sulfate impregnation solution is obtained. Ammonium sulfate, as a slow-release sulfur source, can better provide supplementary sulfur species in the early stage of roasting at higher temperatures, and better compensate for decomposition losses at high temperatures. At the same time, ammonium ions can intercalate into the precursor, expand the interlayer spacing, facilitate the insertion of sulfur species, and facilitate regeneration. Thus, the effect of synergistically improving the catalytic activity and regeneration capacity of the catalyst at higher temperatures is achieved.

[0071] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. 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 cyclopentanol from cyclopentene, characterized in that, Includes the following steps: S1. In a high-pressure reactor, the tin oxide / zirconium-alumina solid acid catalyst is loaded into a basket, and cyclopentene, deionized water and solvent are pumped into the reactor using a peristaltic pump. The high-pressure reactor is then sealed. The molar ratio of cyclopentene to deionized water is (5.8-6.2):1, the mass of the solvent is equal to the mass of cyclopentene, and the mass of the tin oxide / zirconium-alumina solid acid catalyst is 24-26% of the mass of deionized water. S2. After pressurizing and leak testing to ensure good sealing of the reaction, cool down to 5-10℃, purge with nitrogen three times to ensure complete removal of air from the reactor, pressurize with nitrogen to 0.5MPa, stir and heat to 130±2℃, react for 4 hours, cool to 10±2℃, discharge, and centrifuge.

2. The method for preparing cyclopentanol from cyclopentene according to claim 1, characterized in that, The preparation method of the tin oxide / zirconium-alumina solid acid catalyst is as follows: A1. Weigh out tin tetrachloride pentahydrate, zirconium nitrate pentahydrate, and aluminum sulfate octadecahydrate according to n(tin):n(zirconium):n(aluminum) = 8.8:(0.3-0.5):1, dissolve them in deionized water, and prepare a basic solution with a mass fraction of 5%-5.3%. A2. While stirring the base solution, ammonia water is added dropwise to adjust the pH value to 8. The solution is allowed to stand at room temperature until precipitation is complete. Then, it is aged at 5-10℃ for 12-14 hours, filtered, and the filter cake is washed with ammonium acetate solution until the pH value is 7 and dried to obtain the precursor. A3. Prepare a sulfuric acid-ammonium sulfate impregnation solution, which includes 3.0 mol / L sulfuric acid and 0.2-0.3 mol / L ammonium sulfate; A4. After grinding the precursor and passing it through a 100-mesh sieve, impregnate it with the sulfuric acid-ammonium sulfate impregnation solution for 1-1.2 hours, filter it, dry it, and calcine it at 515-520℃ for 2 hours to obtain the product.

3. The method for preparing cyclopentanol from cyclopentene according to claim 2, characterized in that, In A2, the stirring speed is 450-500 rpm, and the mass fraction of ammonia water is 25%-28%.

4. The method for preparing cyclopentanol from cyclopentene according to claim 2, characterized in that, In A2, the mass fraction of ammonium acetate solution is 3.8%-4.2%.

5. The method for preparing cyclopentanol from cyclopentene according to claim 2, characterized in that, In A3, the ratio of sulfuric acid-ammonium sulfate impregnation solution to precursor is (14.5-15.5) mL: 1 g.

6. The method for preparing cyclopentanol from cyclopentene according to claim 2, characterized in that, For both A2 and A3, the drying temperature is 108-112℃ and the drying time is 11.5-12.5h.

7. The method for preparing cyclopentanol from cyclopentene according to claim 1, characterized in that, In S1, the solvent is phenol.

8. The method for preparing cyclopentanol from cyclopentene according to claim 1, characterized in that, In S2, the specific procedure for pressure testing is as follows: pressurize with nitrogen to 4±0.2MPa and test for leaks for 30 minutes.

9. The method for preparing cyclopentanol from cyclopentene according to claim 1, characterized in that, In S2, the stirring speed is 580-600 rpm.

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