Preparation method for preparing cyclic alcohol
By preparing vanadium-silicon molecular sieve catalysts, the problem of low selectivity of cycloalkanes during oxidation was solved, achieving high selectivity and stability in the continuous oxidation of cycloalkanes to produce cycloalkanes. This simplifies the process steps, reduces equipment investment and pollutant emissions, and is suitable for large-scale production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- DALIAN INSTITUTE OF CHEMICAL PHYSICS CHINESE ACADEMY OF SCIENCES
- Filing Date
- 2024-10-22
- Publication Date
- 2026-04-24
AI Technical Summary
Existing cycloalkanes oxidation processes suffer from low selectivity for cycloalcohols, high process costs, severe pollutant emissions, demanding equipment requirements, and long process routes.
A vanadium-silicon molecular sieve catalyst was prepared using a hierarchical porous molecular sieve as the matrix via a mineralizer-assisted method. This catalyst was used to catalyze the oxidation of cycloalkanes to cyclools, exhibiting high selectivity and stability.
It achieves high selectivity and high stability in the continuous oxidation of cycloalkanes to produce cycloalcohols, simplifies reaction steps, reduces equipment investment and pollutant emissions, and is suitable for large-scale production.
Smart Images
Figure CN121913871A_ABST
Abstract
Description
Technical Field
[0001] This application relates to a method for preparing cyclic alcohols, belonging to the field of chemical engineering technology. Background Technology
[0002] Cyclohydric alcohols are important intermediates in pesticides, pharmaceuticals, and organic synthesis, possessing significant market potential. For example, cyclopentanol is primarily used in the production of pharmaceutical raw materials, dyes, and fragrances, and also serves as a solvent for drugs and fragrances. Cyclohexanol, on the other hand, is an important chemical raw material, mainly used in the production of adipic acid, hexamethylenediamine, and caprolactam. It can also be used as a stabilizer in soaps, in the manufacture of disinfectant soaps and detergent emulsions, as a solvent for rubber, resins, nitrocellulose, metal soaps, oils, esters, and ethers, as an admixture in coatings, and as a degreasing agent, stripping agent, dry cleaning agent, and polishing agent for leather. Cyclohexanol is also a raw material for fiber finishing agents, pesticides, and plasticizers.
[0003] Currently, the main industrial method for producing cyclopentanol is through the hydrogenation of cyclopentanone. However, the production of cyclopentanone generates a large amount of pollutants and has a long process route, severely hindering the production of its downstream chemical, cyclopentanol. Therefore, the preparation of cyclopentanol via the oxidation of cyclopentane is of significant research value. Cyclohexane, with cobalt or manganese salts as catalysts, requires air oxidation under high pressure conditions of 120–140°C and 18–24 atmospheres to obtain a mixture of cyclohexaneol and cyclohexanone. This requires extremely sophisticated reaction equipment, increases process costs, and results in low product purity.
[0004] In conclusion, developing a green chemical process for the direct oxidation of cycloalkanes to cycloalcohols is of significant research value. Summary of the Invention
[0005] Hierarchical porous molecular sieves possess a wide pore size distribution, suitable pore wall thickness, and excellent hydrothermal stability, making them suitable as a matrix for catalytic oxidation reactions. Vanadium salts are metals with excellent oxidation activity in hydrocarbon compounds, exhibiting high selectivity. Therefore, using HSZ molecular sieves as a matrix, a vanadium-silicon molecular sieve catalyst can be obtained through a mineralizer-assisted method, possessing both the ability to catalyze the oxidation of cycloalkanes and the ability to selectively generate high-value-added cycloalcohols.
[0006] The purpose of this application is to provide a method for preparing and applying a cyclic alcohol catalyst, overcoming the problem of low selectivity of cyclic alcohols in existing cycloalkane oxidation processes.
[0007] According to one aspect of this application, a method for preparing cyclic alcohols is provided, the method comprising:
[0008] In a reactor, a mixture containing a catalyst, an oxidant, and cycloalkanes is reacted to yield cycloalcohols.
[0009] The catalyst is a vanadium-silicon molecular sieve catalyst.
[0010] Optionally, the preparation method of the vanadium-silicon molecular sieve catalyst includes:
[0011] In a closed reactor, a mixture containing HSZ molecular sieve, vanadium salt, and mineralizer is crystallized, acid-treated, dried, and calcined to obtain the vanadium-silicon molecular sieve catalyst.
[0012] Optionally, the vanadium-silicon molecular sieve catalyst contains 0.5% to 5% vanadium by mass.
[0013] Optionally, the mass percentage of metallic vanadium in the vanadium-silicon molecular sieve catalyst is independently selected from any value of 0.5%, 1%, 2%, 3%, 4%, 5%, or a range between any two of the above.
[0014] Optionally, the mineralizing agent is selected from at least one of magnesium oxide, potassium chloride, ferric sulfate, and lithium chloride.
[0015] Optionally, the vanadium salt is selected from at least one of vanadium pentoxide, vanadium chloride, and vanadium oxysulfate;
[0016] Optionally, the concentration of the mineralizing agent is 0.1 to 1 mol / L.
[0017] Optionally, the concentration of the mineralizing agent is independently selected from any value among 0.1 mol / L, 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L, and 1 mol / L, or a range between any two of the above.
[0018] Optionally, the crystallization temperature is 130–180°C, and the crystallization time is 24–72 h.
[0019] Optionally, the acid used in the acid treatment is selected from at least one of nitric acid, hydrochloric acid, and acetic acid.
[0020] Optionally, the concentration of the acid is 1 to 3 mol / L.
[0021] Optionally, the concentration of the acid is independently selected from any value of 1 mol / L, 1.5 mol / L, 2 mol / L, 2.5 mol / L, 3 mol / L, or a range between any two of the above.
[0022] Optionally, the drying temperature is 100–120°C, and the drying time is 6–12 hours.
[0023] Optionally, the calcination temperature is 400–600°C, and the calcination time is 4–8 hours.
[0024] Optionally, the cycloalkane is selected from cyclopentane and / or cyclohexane.
[0025] Optionally, the mass ratio of the cycloalkane to the catalyst is 1:10 to 50.
[0026] Optionally, the feed rate of the cycloalkane is 0.5 to 1 g / h.
[0027] Optionally, the feed rate of the oxidant is 5 to 20 g / h.
[0028] Optionally, the oxidant is hydrogen peroxide, and the concentration of the hydrogen peroxide is 15-30%.
[0029] Optionally, the reaction temperature is 40–100°C, and the reaction space velocity is 0.5–2 h⁻¹. -1 .
[0030] Optionally, the temperature of the reaction is independently selected from any value of 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or a range between any two of the above.
[0031] Optionally, the space velocity of the reaction is independently selected from 0.5 h⁻¹. -1 1h -1 1.5h -1 2h -1 Any value in or a range between any two of the above.
[0032] This application provides a cyclic alcohol catalyst, prepared by hydrothermal synthesis, with vanadium-silicon molecular sieve as the active component. The active component is obtained through a mineralizer-assisted hydrothermal synthesis followed by acid treatment and calcination. This catalyst is used in the continuous oxidation of cycloalkanes to produce cyclic alcohols. The catalyst, synthesized using a mineralizer-assisted method, possesses the advantage of a wide pore size range. Using the catalyst of this invention, a one-step, continuous process for preparing cyclic alcohols is achieved, characterized by its simple composition and low investment. This catalyst enables the environmentally friendly and efficient production of highly selective cyclic alcohols.
[0033] The beneficial effects that this application can produce include:
[0034] 1) The present application describes the continuous oxidation of cycloalkanes to produce cycloalcohols, which involves simple reaction steps, simple equipment routes, and low investment.
[0035] 2) The method for producing cycloalcohols by continuous oxidation of cycloalkanes provided in this application produces very little waste, only water, and has minimal pollution. It has extremely high environmental benefits and is an environmentally friendly process.
[0036] 3) The method for producing cycloalcohols by continuous oxidation of cycloalkanes provided in this application allows the catalyst to operate stably for more than 500 hours under preferred process conditions. Attached Figure Description
[0037] Figure 1 This is a catalyst lifetime evaluation spectrum from Example 2 of this application. Detailed Implementation
[0038] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.
[0039] Unless otherwise specified, all raw materials used in the embodiments of this application were purchased through commercial channels.
[0040] The qualitative and quantitative analysis of the product in this application was performed offline using an Agilent 7890A gas chromatograph, with separation using an Agilent HP-5 capillary column and detection and analysis using a flame ionization detector (FID).
[0041] Conversion rate = ((Initial moles of cycloalkanes - Remaining moles of cycloalkanes) / Initial moles of cycloalkanes) × 100%
[0042] Selectivity = (moles of cycloalcohols formed / (initial moles of cycloalkanes - remaining moles of cycloalkanes)) × 100%.
[0043] In this application, the preparation method of HSZ molecular sieve gel precursor is as follows: 8.9g piperidine (PI) and 31.5g deionized water are added to a 100mL polytetrafluoroethylene beaker and stirred at room temperature for 0.5h; then 5.8g H3BO3 is added and stirred for 0.5h until dissolved; 4.2g fumed silica is added in 3 portions and stirred for 1h to form a uniform gel precursor.
[0044] Example 1
[0045] Preparation and application of VH-HSZ catalysts
[0046] 1 g of the synthesized HSZ molecular sieve gel precursor, 0.05 g of VOSO4·5H2O, and 0.01 g of ferric sulfate mineralizing agent were stirred evenly and then placed in a 100 mL crystallization vessel. The vessel was then placed in a rotary oven and crystallized at 140 °C for 12 h at a rotation speed of 120 r / min. The temperature was then increased to 170 °C and crystallization continued for 48 h. After crystallization and synthesis, the sample was filtered, washed, and dried. The sample was then acid-washed with 2 mol / L nitric acid for 15 h, washed with deionized water until neutral, and dried overnight in a 120 °C oven. After that, it was ground evenly and calcined in a muffle furnace at 550 °C for 6 h to obtain VH-HSZ molecular sieve with a V content of 1.2%.
[0047] 1 g of VH-HSZ catalyst was loaded into a fixed-bed reactor. A mixed solution of cyclopentane and hydrogen peroxide was pumped in, with a hydrogen peroxide to cyclopentane mass ratio of 6.5 and a hydrogen peroxide solution concentration of 15%. The reaction temperature was controlled at 60 °C and the reaction space velocity was 2 h⁻¹. -1 Analysis of the obtained product showed that the cyclopentane conversion rate was 59% and the cyclopentanol selectivity was 80.2%.
[0048] Example 2
[0049] Preparation and application of VH-HSZ catalysts
[0050] 1 g of the synthesized HSZ molecular sieve gel precursor, 0.15 g of VCl4, and 0.1 g of mineralizing agent KCl were stirred evenly and then placed in a 100 mL crystallization vessel. The vessel was then placed in a rotary oven and crystallized at 130 °C for 12 h at a rotation speed of 120 r / min. The temperature was then increased to 170 °C and crystallization was continued for another 48 h. After crystallization and synthesis, the sample was filtered, washed, and dried. The sample was then acid-washed with 1 mol / L hydrochloric acid for 20 h, washed with deionized water until neutral, and dried and calcined under the same conditions to obtain VH-HSZ molecular sieve with a V content of 3.5%.
[0051] 1 g of VH-HSZ catalyst was loaded into a fixed-bed reactor, and a mixed solution of cyclopentane and hydrogen peroxide was pumped in, wherein the mass ratio of hydrogen peroxide to cyclopentane was 5, the hydrogen peroxide solution concentration was 20%, the reaction temperature was controlled at 80 °C, and the reaction space velocity was 1 h⁻¹. -1 Analysis of the obtained product showed a cyclohexane conversion rate of 40% and a cyclohexanol selectivity of 80.5%, and it could operate stably for 500 hours (see...). Figure 1 ).
[0052] Example 3
[0053] Preparation and application of VH-HSZ catalysts
[0054] 1 g of the synthesized HSZ molecular sieve gel precursor, 0.1 g of V₂O₅, and 0.1 g of magnesium oxide mineralizer were stirred evenly and then transferred to a 100 mL crystallization vessel. The vessel was placed in a rotary oven and crystallized at 130 °C for 12 h at a rotation speed of 120 r / min. The temperature was then increased to 170 °C and crystallization continued for another 24 h. After crystallization and synthesis, the sample was filtered, washed, and dried. The sample was then acid-washed with 3 mol / L acetic acid for 10 h, washed with deionized water until neutral, and dried and calcined under the same conditions to obtain VH-HSZ molecular sieve with a V content of 4.8%.
[0055] 1 g of VH-HSZ catalyst was loaded into a fixed-bed reactor. A mixed solution of cyclopentane and hydrogen peroxide was pumped in, with a hydrogen peroxide to cyclopentane mass ratio of 1.6 and a hydrogen peroxide solution concentration of 30%. The reaction temperature was controlled at 80 °C, and the reaction space velocity was 0.5 h⁻¹. -1 Analysis of the obtained product showed that the cyclopentane conversion rate was 60.8% and the cyclopentanol selectivity was 70%, and it could operate stably for more than 500 hours.
[0056] Example 4
[0057] Application of VH-HSZ catalyst
[0058] 1 g of the VH-HSZ catalyst prepared in Example 3 was loaded into a fixed-bed reactor. A mixed solution of cyclopentane and hydrogen peroxide was pumped in, wherein the mass ratio of hydrogen peroxide to cyclopentane was 3.2, the concentration of hydrogen peroxide solution was 15%, the reaction temperature was controlled at 100 °C, and the reaction space velocity was 0.5 h⁻¹. -1 Analysis of the obtained product showed that the cyclopentane conversion rate was 72% and the cyclopentanol selectivity was 60.3%.
[0059] Example 5
[0060] Application of VH-HSZ catalyst
[0061] 1 g of VH-HSZ catalyst prepared in Example 2 was loaded into a fixed-bed reactor. A mixed solution of cyclopentane and hydrogen peroxide was pumped in, wherein the mass ratio of hydrogen peroxide to cyclopentane was 6.5, the concentration of hydrogen peroxide solution was 15%, the reaction temperature was controlled at 100 °C, and the reaction space velocity was 1 h⁻¹. -1 Analysis of the obtained product showed that the cyclohexane conversion rate was 55% and the cyclohexanol selectivity was 50.7%.
[0062] Comparative Example 1
[0063] 1 g of TS-1 catalyst was loaded into a fixed-bed reactor, and a mixed solution of cyclopentane and hydrogen peroxide was pumped in, wherein the mass ratio of hydrogen peroxide to cyclopentane was 7.3, the hydrogen peroxide solution concentration was 20%, the reaction temperature was controlled at 60 °C, and the reaction space velocity was 1 h⁻¹. -1 Analysis of the obtained product showed that the cyclopentane conversion rate was 40% and the cyclopentanol selectivity was 12%.
[0064] Comparative Example 2
[0065] 1 g of HSZ catalyst was loaded into a fixed-bed reactor, and a mixed solution of cyclopentane and hydrogen peroxide was pumped in, wherein the mass ratio of hydrogen peroxide to cyclopentane was 7.3, the hydrogen peroxide solution concentration was 20%, the reaction temperature was controlled at 80 °C, and the reaction space velocity was 0.5 h⁻¹. -1Analysis of the obtained product showed that the cyclopentane conversion rate was 38% and the cyclopentanol selectivity was 60%.
[0066] Comparative Example 3
[0067] 1 g of TS-1 catalyst was loaded into a fixed-bed reactor, and a mixed solution of cyclopentane and hydrogen peroxide was pumped in, wherein the mass ratio of hydrogen peroxide to cyclopentane was 5, the hydrogen peroxide solution concentration was 20%, the reaction temperature was controlled at 80 °C, and the reaction space velocity was 1 h⁻¹. -1 Analysis of the obtained product showed that the cyclohexane conversion rate was 20% and the cyclohexanol selectivity was 40.9%.
[0068] Based on the above comparative analysis results, the vanadium-silicon molecular sieve catalyst constructed using this invention can achieve high selectivity and high stability in the continuous oxidation of cycloalkanes to cyclools. Moreover, the catalyst has a simple composition, produces no waste, and is suitable for large-scale production.
[0069] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.
Claims
1. A method for preparing cyclic alcohols, characterized in that, The preparation method includes: In a reactor, a mixture containing a catalyst, an oxidant, and cycloalkanes is reacted to yield cycloalcohols. The catalyst is a vanadium-silicon molecular sieve catalyst.
2. The preparation method according to claim 1, characterized in that, The preparation method of the vanadium-silicon molecular sieve catalyst includes: In a closed reactor, a mixture containing HSZ molecular sieve, vanadium salt, and mineralizer is crystallized, acid-treated, dried, and calcined to obtain the vanadium-silicon molecular sieve catalyst. Preferably, the vanadium-silicon molecular sieve catalyst contains 0.5% to 5% vanadium by mass.
3. The preparation method according to claim 2, characterized in that, The mineralizing agent is selected from at least one of magnesium oxide, potassium chloride, ferric sulfate, and lithium chloride.
4. The preparation method according to claim 2, characterized in that, The vanadium salt is selected from at least one of vanadium pentoxide, vanadium chloride, and vanadium oxysulfate. Preferably, the concentration of the mineralizing agent is 0.1 to 1 mol / L.
5. The preparation method according to claim 2, characterized in that, The crystallization temperature is 130–180°C, and the crystallization time is 24–72 h; Preferably, the acid used in the acid treatment is selected from at least one of nitric acid, hydrochloric acid, and acetic acid; Preferably, the concentration of the acid is 1 to 3 mol / L.
6. The preparation method according to claim 2, characterized in that, The drying temperature is 100-120℃, and the drying time is 6-12 hours; Preferably, the calcination temperature is 400–600°C, and the calcination time is 4–8 hours.
7. The preparation method according to claim 1, characterized in that, The cycloalkane is selected from cyclopentane and / or cyclohexane.
8. The preparation method according to claim 1, characterized in that, The mass ratio of the cycloalkane to the catalyst is 1:10 to 50.
9. The preparation method according to claim 1, characterized in that, The oxidant is hydrogen peroxide, and the concentration of the hydrogen peroxide is 15-30%.
10. The preparation method according to claim 1, characterized in that, The reaction temperature is 40–100°C, and the reaction space velocity is 0.5–2 h⁻¹. -1 .