Activated carbon-supported multi-metal catalysts, their preparation methods and applications; preparation method of 1-(4-chlorophenyl)-3-pyrazole alcohol.
By using activated carbon-supported multi-metal catalysts, the problems of easy catalyst precipitation and environmental pollution have been solved, and the preparation of 1-(4-chlorophenyl)-3-pyrazolol with high efficiency and low cost has been achieved, thus achieving the goal of green production.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- EAST CHINA UNIV OF SCI & TECH
- Filing Date
- 2024-02-08
- Publication Date
- 2026-05-26
AI Technical Summary
The catalyst used in the preparation of 1-(4-chlorophenyl)-3-pyrazol is prone to precipitation, resulting in reduced catalytic activity, difficulty in recovery, serious environmental pollution, and high production costs.
Multi-metal catalysts, including transition metals, alkaline earth metals, and rare earth metal ions, are supported on activated carbon to form a highly efficient gas-liquid-solid three-phase reaction system. Molecular oxygen is used as the oxidant and an alkaline aqueous solution is used as the solvent to carry out the oxidation reaction.
This improved the yield of 1-(4-chlorophenyl)-3-pyrazol, reduced wastewater generation, lowered production costs, and achieved a green, safe, and efficient oxidation reaction.
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Figure BDA0004702296670000011 
Figure BDA0004702296670000021
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of preparing N-substituted 3-hydroxypyrazole compounds, specifically to an activated carbon-supported multi-metal catalyst and its preparation method and application, and a method for preparing 1-(4-chlorophenyl)-3-pyrazole alcohol. Background Technology
[0002] Pyraclostrobin, also known as azoxystrobin, is a broad-spectrum, highly effective methoxyacrylate fungicide with a pyrazole structure. Its chemical name is N-methoxy-N-2-[(1-p-chlorophenyl)-3-pyrazoleoxymethyl]phenylcarbamate. Discovered by BASF in 1993 and successfully launched in the European market in late 2001, it is primarily used to control various diseases caused by Ascomycetes, Basidiomycetes, Deuteromycetes, and Oomycetes, including leaf blight, rust, powdery mildew, downy mildew, blight, anthracnose, scab, brown spot, and damping-off. It is currently the most bioactive methoxyacrylate fungicide and also possesses potential curative activity. Due to its low toxicity, low residue, safety to non-target organisms, and environmental friendliness, pyraclostrobin has a very broad application prospect.
[0003] 1-(4-Chlorophenyl)-3-pyrazolol is an important intermediate in the synthesis of pyraclostrobin. Currently, 1-(4-Chlorophenyl)-3-pyrazolol is produced industrially by oxidizing 1-(4-Chlorophenyl)pyrazolidine-3-one with hydrogen peroxide. The reaction of hydroxylating 1-(4-Chlorophenyl)pyrazolidine-3-one with hydrogen peroxide to produce 1-(4-Chlorophenyl)-3-pyrazolol and water is shown in equation (1):
[0004]
[0005] The method for producing 1-(4-chlorophenyl)-3-pyrazolol from 1-(4-chlorophenyl)pyrazolidine-3-one by oxidizing with hydrogen peroxide has been reported in the literature (Agrochemicals, 2015, 46(7): 14-17; CN105968048A; Zhejiang Chemical Industry, 2015, (7): 14-17; Fine Chemical Intermediates, 2018, 48(1): 28-30). However, the defects of this process are also obvious: 1. The use of hydrogen peroxide as an oxidant is dangerous. There have been explosion accidents in agrochemical companies that used hydrogen peroxide oxidation process, which poses a great safety hazard; 2. The generated product 1-(4-chlorophenyl)-3-pyrazolol is easily oxidized again, resulting in low selectivity of the target product and high cost; 3. The use of hydrogen peroxide as an oxidant generates a large amount of wastewater, which causes serious environmental pollution.
[0006] Molecular oxygen, as a green and inexpensive oxidant, can also oxidize 1-(4-chlorophenyl)pyrazolidine-3-one to produce 1-(4-chlorophenyl)-3-pyrazolol and water, as shown in reaction (2):
[0007]
[0008] However, due to the weak oxidizing power of molecular oxygen, the key to achieving the air oxidation of 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol is to develop a highly efficient and selective catalyst. Patent US 6040458 proposes using copper chloride or cobalt chloride as a catalyst to oxidize 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol with pure oxygen. Literature (US 5922886; Guangzhou Chemical Industry, 2015, 43(19):76-78) reports the oxidation of 1-(4-chlorophenyl)pyrazolidine-3-one dissolved in N,N-dimethylformamide (DMF) to 1-(4-chlorophenyl)-3-pyrazolol under the catalysis of FeCl3, but DMF is volatile, highly toxic, and has complex post-treatment. Patent CN103588708A proposes using FeCl3 as a catalyst in an alkaline solution to oxidize 1-(4-chlorophenyl)pyrazolidine-3-one with air to produce 1-(4-chlorophenyl)-3-pyrazol. Patent CN106008350A proposes using FeCl3 as a catalyst in a carboxylic acid solution to oxidize 1-(4-chlorophenyl)pyrazolidine-3-one with air to produce 1-(4-chlorophenyl)-3-pyrazol. However, due to the low solubility of 1-(4-chlorophenyl)pyrazolidine-3-one in acidic solutions, this oxidation reaction is difficult to proceed smoothly. Literature (Pesticides, 2011, 50(5):327-328; Pesticide Science and Management, 2012, 33(1):18-21) reported that 1-(4-chlorophenyl)pyrazolidine-3-one was oxidized to 1-(4-chlorophenyl)-3-pyrazolol using K3Fe(CN)6 as a catalyst and air as an oxidant.
[0009] Currently reported catalysts for the air oxidation of 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol are mainly metal salts. However, these metal salts readily form hydroxide precipitates in strongly alkaline solutions, which reduces catalytic activity and causes the metal precipitates to mix into the product, lowering product quality and increasing purification difficulty. Furthermore, the inorganic ions in the wastewater are mixed salts, making it impossible to prepare high-content by-product salts, which are difficult to recycle and reuse, resulting in serious environmental pollution and increasing the difficulty of treatment and production costs. Therefore, no industrial-scale equipment for the air oxidation process to produce 1-(4-chlorophenyl)-3-pyrazolol has been reported. Summary of the Invention
[0010] The purpose of this invention is to solve the problems of reduced catalytic activity, difficulty in recovery, and serious environmental pollution caused by the easy precipitation of existing catalysts used in the preparation process of 1-(4-chlorophenyl)-3-pyrazolol. This invention provides an activated carbon-supported multi-metal catalyst, its preparation method and application, and a method for preparing 1-(4-chlorophenyl)-3-pyrazolol. This catalyst can achieve a significantly higher yield of 1-(4-chlorophenyl)-3-pyrazolol and a lower wastewater generation.
[0011] To achieve the above objectives, a first aspect of the present invention provides an activated carbon-supported multi-metal catalyst, the catalyst comprising an activated carbon support and an active metal component supported on the support, wherein the active metal component comprises transition metal ions, alkaline earth metal ions and rare earth metal ions.
[0012] Furthermore, the loading of metal ions in the catalyst is 3.1–35 wt%, preferably 18.7–35 wt%, more preferably 18.7–25 wt%; wherein the loading of transition metal ions is 2–30 wt%, preferably 10–30 wt%, more preferably 10–20 wt%; the loading of alkaline earth metal ions is 1–15 wt%, preferably 3–10 wt%; and the loading of rare earth metal ions is 0.1–8 wt%, preferably 0.5–5 wt%.
[0013] The transition metal ions are selected from one or two of iron, cobalt, silver, copper, manganese, vanadium, niobium, molybdenum, tungsten, zirconium, nickel, zinc, hafnium, titanium, and chromium; the alkaline earth metal ions are selected from one of beryllium, magnesium, calcium, strontium, and barium; and the rare earth metal ions are selected from one of cerium, lanthanum, europium, yttrium, praseodymium, samarium, and neodymium.
[0014] The activated carbon carrier is selected from coconut shell charcoal, coal charcoal, wood chip charcoal, pitch charcoal, etc. The activated carbon carrier can be in powder or granular form.
[0015] The concept of this invention is as follows: activated carbon materials have a well-developed pore structure and a huge specific surface area, generally reaching 700-2000 m². 2 / g, possessing a unique porous structure and abundant surface-active functional groups, exhibits chemical stability, high mechanical strength, and resistance to acids, alkalis, and heat. Activated carbon has a strong affinity for metal ions, making it an excellent support for metal compounds. Some transition metal compounds possess strong oxidation catalytic activity. Alkaline earth metals can improve the dispersion and stability of transition metals and increase active sites, while rare earth metal ions can promote valence state transitions of transition metal ions and increase oxygen vacancies in the catalyst. Therefore, loading these metal compounds onto activated carbon can significantly increase the specific surface area, provide suitable pore structures and active centers for chemical reactions. Moreover, because activated carbon has the ability to transfer electrons, it is also an excellent oxidation catalyst. Thus, activated carbon-supported metal catalysts can exert a multi-component synergistic effect, thereby improving catalyst activity.
[0016] The second aspect of this invention provides a method for preparing the activated carbon-supported multi-metal catalyst described in the first aspect of this invention. The method includes: firstly, dissolving a compound containing transition metal ions, a compound containing alkaline earth metal ions, and a compound containing rare earth metal ions in an acidic solution to prepare a solution; then immersing a certain mass of activated carbon support in the solution; and finally heating the solution to dryness or filtering to obtain the catalyst. The concentration of the metal ion compound in the solution is preferably 5–55 wt%.
[0017] Preferably, the conditions for heating and evaporation include: refluxing at 40-80°C for 1-8 hours and then evaporating the water at 80-100°C, or stirring the solution in a water bath at 80-100°C until the water is evaporated.
[0018] Preferably, the pH of the acidic solution is between 0 and 6, with an optimal value of 2 to 5, and the acidic solution is selected from a solution containing at least one of hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, tartaric acid, acetic acid, or propionic acid.
[0019] The metal ions (including transition metal ions, alkaline earth metal ions, and rare earth metal ions) are derived from metal compounds soluble in acidic solutions, such as acetates, propions, butyrates, nitrates, chlorides, carbonates, sulfates, oxides, and hydroxides. A third aspect of this invention provides the application of the catalyst described in the first aspect of this invention in the oxidation reaction of pyrazolone compounds to prepare N-substituted 3-hydroxypyrazole compounds.
[0020] The fourth aspect of the present invention provides a method for preparing 1-(4-chlorophenyl)-3-pyrazolol, the method comprising: contacting 1-(4-chlorophenyl)pyrazolidine-3-one with a catalyst in the presence of oxygen, wherein the catalyst is the catalyst described in the first aspect of the present invention.
[0021] Preferably, the catalyst is dried before contacting it with 1-(4-chlorophenyl)pyrazolidine-3-one, and then activated by heating under nitrogen protection. The preferred activation temperature is 150°C to 400°C, with an optimal value of 180°C to 300°C, and the activation time is 1 to 20 hours, with an optimal value of 2 to 9 hours.
[0022] Preferably, the drying conditions include: a temperature of 100℃~120℃ and a time of 4~24 hours.
[0023] Preferably, the 1-(4-chlorophenyl)pyrazolidine-3-one is contacted with the catalyst in a gas-liquid-solid three-phase catalytic oxidation reactor, using an alkaline aqueous solution as the solvent and a gas containing 20–100 v / v% oxygen as the oxidant to oxidize 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol. Preferably, the oxidation reaction is carried out at atmospheric pressure. Preferably, the oxidation reaction is carried out at a temperature of 20°C–100°C, with an optimal temperature of 40°C–85°C. The inlet gas of the reactor is air, pure oxygen, or oxygen-enriched air, preferably air. The concentration of 1-(4-chlorophenyl)pyrazolidine-3-one in the reactor feed is 5–65 wt%, with an optimal concentration of 8–50 wt%.
[0024] The alkaline aqueous solution is an aqueous solution with an alkaline concentration of 1 to 40 wt%, with an optimal concentration of 5 to 20 wt%, and preferably sodium hydroxide or potassium hydroxide.
[0025] The gas-liquid-solid three-phase catalytic oxidation reactor has no special requirements and can be carried out in a conventional slurry bed or trickle bed. When using a fixed bed, the gas and liquid phases in the reactor can operate in upward co-current, downward co-current, or counter-current operation. When using a slurry bed, the concentration of the catalyst in the reactor is 2–25 g / L, with an optimal value of 3–15 g / L.
[0026] This invention uses molecular oxygen as an oxidant and an alkaline aqueous solution as a solvent. Under the action of a multi-metal catalyst supported on activated carbon, 1-(4-chlorophenyl)pyrazolidine-3-one is oxidized to 1-(4-chlorophenyl)-3-pyrazol. Compared with the hydrogen peroxide oxidation method, it can significantly reduce wastewater discharge, eliminate safety hazards, reduce equipment corrosion, reduce environmental pollution, increase the yield of 1-(4-chlorophenyl)-3-pyrazol, and reduce production costs. Compared with other molecular oxygen oxidation methods, it has high conversion rate and selectivity, improved product purity, and reduced wastewater generation, achieving the goals of being green, safe, efficient, low-consumption, and high-quality, and realizing the unity of economic, social, and environmental benefits. Detailed Implementation
[0027] The present invention will be further described below with reference to embodiments, but these embodiments are not intended to limit the scope of the invention.
[0028] As a specific embodiment, the present invention provides a method for preparing 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol. The method includes: in a reactor, at atmospheric pressure and 20-100°C, using 1-(4-chlorophenyl)pyrazolidine-3-one as raw material, oxygen as oxidant, alkaline aqueous solution as solvent, and activated carbon loaded with transition metal ions, alkaline earth metal ions and rare earth metal ions as active components as a solid catalyst, forming a gas-liquid-solid three-phase reaction system, oxidizing 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol;
[0029] The concentration of 1-(4-chlorophenyl)pyrazolidine-3-one in the feed to the reactor is 5-65 wt%.
[0030] The inlet gas of the reactor contains 20-100 v / v% oxygen;
[0031] The alkaline aqueous solution is an aqueous solution with an alkalinity concentration of 1 to 40 wt%.
[0032] The loading of metal ions on the catalyst is 3.1–35 wt%.
[0033] The transition metal ions are selected from one or two of iron, cobalt, silver, copper, manganese, vanadium, niobium, molybdenum, tungsten, zirconium, nickel, zinc, hafnium, titanium, and chromium; the alkaline earth metal ions are selected from one of beryllium, magnesium, calcium, strontium, and barium; and the rare earth metal ions are selected from one of cerium, lanthanum, europium, yttrium, praseodymium, samarium, and neodymium. The metal ions (including transition metal ions, alkaline earth metal ions, and rare earth metal ions) are derived from metal compounds soluble in solvents, such as acetates, propionates, butyrates, nitrates, chlorides, carbonates, sulfates, oxides, and hydroxides.
[0034] Example 1
[0035] Coconut shell activated carbon was immersed in a hydrochloric acid aqueous solution with pH 3.0 containing cobalt sulfate, calcium chloride and cerium nitrate. After heating and reflux for 6 hours, the water was evaporated at 90°C, dried at 110°C for 4 hours, and then activated at 280°C for 5 hours under nitrogen protection to obtain a catalyst with a cobalt loading of 15 wt%, a calcium loading of 5 wt%, and a cerium loading of 1 wt%.
[0036] The experiment was carried out in a 500 ml stirred reactor. 400 ml of 7.5 wt% sodium hydroxide solution, 50 g of 1-(4-chlorophenyl)pyrazolidine-3-one, and 2 g of the previously prepared 80-100 mesh activated carbon-supported multi-metal catalyst were added. The reaction was carried out at 80 °C under normal pressure with an air flow rate of 800 mL / min. Liquid samples were taken every 0.5 h for liquid chromatography analysis. After 3 h of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one was 96.3%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol was 92.1%.
[0037] Example 2
[0038] The preparation method of activated carbon-supported multi-metal catalyst is as described in Example 1.
[0039] The experiment was conducted in a fixed-bed reactor with a height of 80 cm and an inner diameter of 2 cm, containing a multi-metal catalyst supported on 20-40 mesh activated carbon. The gas and liquid phases flowed concurrently from top to bottom through the reactor, with a liquid flow rate of 5 ml / min and an air flow rate of 900 ml / min. The liquid feed consisted of a 7.5 wt% sodium hydroxide solution and a 13 wt% concentration of 1-(4-chlorophenyl)pyrazolidine-3-one. The reaction temperature was 80 °C, and the operation was carried out at atmospheric pressure. The reactor outlet liquid was analyzed by liquid chromatography, and the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one was 86.7%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol was 84.5%.
[0040] Example 3
[0041] Coconut shell activated carbon was immersed in an aqueous acetic acid solution with pH 4.0 containing manganese acetate, beryllium chloride, and lanthanum nitrate. After heating and reflux for 6 hours, the water was evaporated at 90°C, dried at 110°C for 4 hours, and then activated at 260°C for 6 hours under nitrogen protection to obtain a catalyst with a manganese loading of 18 wt%, a beryllium loading of 4 wt%, and a lanthanum loading of 0.5 wt%.
[0042] The experiment was carried out in a 500 ml stirred reactor. 400 ml of 10.0 wt% sodium hydroxide solution, 50 g of 1-(4-chlorophenyl)pyrazolidine-3-one, and 2.5 g of the previously prepared 80-100 mesh activated carbon-supported multi-metal catalyst were added. The reaction was carried out at 90 °C under normal pressure with an air flow rate of 700 mL / min. Liquid samples were taken every 0.5 h after the reaction started for analysis by liquid chromatography. After 3 h of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one was 94.1%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol was 90.2%.
[0043] Example 4
[0044] Coal-based activated carbon was immersed in a sulfuric acid aqueous solution with pH 2.5 containing ferrous sulfate, barium chloride, and lanthanum nitrate. After heating and reflux for 6 hours, the water was evaporated at 90°C, dried at 110°C for 4 hours, and then activated at 240°C for 7 hours under nitrogen protection to obtain a catalyst with an iron loading of 13 wt%, a barium loading of 5 wt%, and a lanthanum loading of 0.7 wt%.
[0045] The experiment was carried out in a 500 ml stirred reactor. 400 ml of 5.0 wt% sodium hydroxide solution, 50 g of 1-(4-chlorophenyl)pyrazolidine-3-one, and 3.0 g of the previously prepared 80-100 mesh activated carbon-supported multi-metal catalyst were added. The reaction was carried out at 80 °C under normal pressure with an air flow rate of 600 mL / min. Liquid samples were taken every 0.5 h after the reaction started for analysis by liquid chromatography. After 3 h of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one was 96.5%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol was 92.1%.
[0046] Example 5
[0047] Wood-based activated carbon was immersed in an aqueous acetic acid solution at pH 4.0 containing cobalt acetate, manganese acetate, strontium chloride, and lanthanum nitrate. After heating under reflux for 6 hours, the water was evaporated at 90°C, dried at 110°C for 4 hours, and then activated at 270°C for 5 hours under nitrogen protection to obtain a catalyst with a cobalt loading of 8.5 wt%, a manganese loading of 5 wt%, a strontium loading of 4.5 wt%, and a lanthanum loading of 0.5 wt%.
[0048] The experiment was carried out in a 500 ml stirred reactor. 400 ml of 7.0 wt% potassium hydroxide solution, 50 g of 1-(4-chlorophenyl)pyrazolidine-3-one, and 1.5 g of the previously prepared 80-100 mesh activated carbon-supported multi-metal catalyst were added. The reaction was carried out at 75 °C under normal pressure with an air flow rate of 500 mL / min. Liquid samples were taken every 0.5 h after the reaction started for analysis by liquid chromatography. After 3 h of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one was 97.2%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol was 93.1%.
[0049] Example 6
[0050] The preparation method of activated carbon supported multi-metal catalyst is the same as in Example 1, except that the catalyst prepared in this example has a cobalt loading of 30 wt%, a calcium loading of 3 wt%, and a cerium loading of 2 wt%.
[0051] The preparation method of 1-(4-chlorophenyl)-3-pyrazolol is as described in Example 1, except that the catalyst of this example is used, and after 3 hours of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one is 98.1%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol is 85.2%.
[0052] Example 7
[0053] The preparation method of activated carbon supported multi-metal catalyst is the same as in Example 1, except that the catalyst prepared in this example has a cobalt loading of 20 wt%, a calcium loading of 3 wt%, and a cerium loading of 2 wt%.
[0054] The preparation method of 1-(4-chlorophenyl)-3-pyrazolol is as described in Example 1, except that the catalyst of this example is used, and after 3 hours of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one is 97.1%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol is 90.2%.
[0055] Example 8
[0056] The preparation method of activated carbon supported multi-metal catalyst is the same as in Example 1, except that the catalyst prepared in this example has a cobalt loading of 2 wt%, a calcium loading of 15 wt%, and a cerium loading of 8 wt%.
[0057] The preparation method of 1-(4-chlorophenyl)-3-pyrazolol is as described in Example 1, except that the catalyst of this example is used, and after 3 hours of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one is 80.9%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol is 70.2%.
[0058] Example 9
[0059] The preparation method of activated carbon supported multi-metal catalyst is the same as in Example 1, except that the catalyst prepared in this example has a cobalt loading of 5 wt%, a calcium loading of 3 wt%, and a cerium loading of 0.3 wt%.
[0060] The preparation method of 1-(4-chlorophenyl)-3-pyrazolol is as described in Example 1, except that the catalyst of this example is used. After 3 hours of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one is 87.1%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol is 73.6%.
[0061] Example 10
[0062] The preparation method of activated carbon supported multi-metal catalyst is the same as in Example 1, except that the catalyst prepared in this example has a cobalt loading of 2 wt%, a calcium loading of 1 wt%, and a cerium loading of 0.1 wt%.
[0063] The preparation method of 1-(4-chlorophenyl)-3-pyrazolol is as described in Example 1, except that the catalyst of this example is used, and after 3 hours of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one is 74.2%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol is 62.6%.
[0064] Example 11
[0065] The preparation method of activated carbon supported multi-metal catalyst is the same as in Example 1, except that the catalyst prepared in this example has a cobalt loading of 10 wt%, a calcium loading of 10 wt%, and a cerium loading of 5 wt%.
[0066] The preparation method of 1-(4-chlorophenyl)-3-pyrazolol is as described in Example 1, except that the catalyst of this example is used, and after 3 hours of reaction, the conversion rate of 1-(4-chlorophenyl)pyrazolidine-3-one is 93.1%, and the yield of 1-(4-chlorophenyl)-3-pyrazolol is 87.2%.
[0067] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.
Claims
1. A method for preparing 1-(4-chlorophenyl)-3-pyrazol, characterized in that, The method includes: contacting 1-(4-chlorophenyl)pyrazolidine-3-one with a catalyst in the presence of oxygen, wherein the catalyst is an activated carbon-supported multi-metal catalyst, the catalyst comprising an activated carbon support and an active metal component supported on the support, wherein the active metal component comprises transition metal ions, alkaline earth metal ions and rare earth metal ions; the transition metal is selected from one or two of iron, cobalt, manganese and nickel, the alkaline earth metal is selected from beryllium, magnesium, calcium, strontium and barium, and the rare earth metal is selected from cerium and lanthanum.
2. The method for preparing 1-(4-chlorophenyl)-3-pyrazolol according to claim 1, characterized in that, The catalyst has a metal ion loading of 3.1–35 wt%; wherein the transition metal ion loading is 2–30 wt%; the alkaline earth metal ion loading is 1–15 wt%; and the rare earth metal ion loading is 0.1–8 wt%. The activated carbon carrier is selected from one of coconut shell carbon, coal carbon, wood chip carbon, and pitch carbon.
3. The method for preparing 1-(4-chlorophenyl)-3-pyrazolol according to claim 2, characterized in that, The catalyst has a metal ion loading of 18.7-35 wt%; of which the transition metal ion loading is 10-30 wt%; the alkaline earth metal ion loading is 3-10 wt%; and the rare earth metal ion loading is 0.5-5 wt%.
4. The method for preparing 1-(4-chlorophenyl)-3-pyrazol according to any one of claims 1 to 3, characterized in that, The method for preparing the catalyst includes: first, dissolving a compound containing transition metal ions, a compound containing alkaline earth metal ions, and a compound containing rare earth metal ions in an acidic solution to prepare a solution; then, immersing a certain mass of activated carbon support in the solution; and finally, heating the solution to dryness or filtering it to obtain the catalyst.
5. The method for preparing 1-(4-chlorophenyl)-3-pyrazolol according to claim 4, characterized in that, The conditions for heating and evaporation include: refluxing at 40~80℃ for 1-8 hours and then evaporating the water at 80~100℃, or stirring the solution in a water bath at 80~100℃ until the water evaporates; the pH of the acidic solution is between 0 and 6 and not 0, and the acidic solution is selected from a solution containing at least one of hydrochloric acid, nitric acid, sulfuric acid, oxalic acid, tartaric acid, acetic acid or propionic acid. The transition metal ions, alkaline earth metal ions, and rare earth metal ions are derived from metal compounds that are soluble in acidic solutions.
6. The method for preparing 1-(4-chlorophenyl)-3-pyrazolol according to claim 1, characterized in that, Before contacting 1-(4-chlorophenyl)pyrazolidine-3-one with the catalyst, the catalyst is dried and then activated by heating under nitrogen protection. The activation temperature is 150℃~400℃, and the activation time is 1~20 hours; The drying conditions include: a temperature of 100℃~120℃ and a time of 4~24 hours.
7. The method for preparing 1-(4-chlorophenyl)-3-pyrazol according to claim 6, characterized in that, The contact between 1-(4-chlorophenyl)pyrazolidine-3-one and the catalyst is carried out in a gas-liquid-solid three-phase catalytic oxidation reactor, with an alkaline aqueous solution as the solvent and a gas containing 20~100 v / v% oxygen as the oxidant, to oxidize 1-(4-chlorophenyl)pyrazolidine-3-one to 1-(4-chlorophenyl)-3-pyrazolol. The oxidation reaction is carried out at a temperature of 20℃ to 100℃; the concentration of 1-(4-chlorophenyl)pyrazolidine-3-one in the feed to the reactor is 5 to 65 wt%. The alkaline aqueous solution is an aqueous solution with an alkalinity concentration of 1~40wt%.
8. The method for preparing 1-(4-chlorophenyl)-3-pyrazolol according to claim 7, characterized in that, The oxidation reaction is carried out under normal pressure; the oxidation reaction is carried out at a temperature of 40℃~85℃; the inlet gas of the reactor is air; the concentration of 1-(4-chlorophenyl)pyrazolidine-3-one in the feed of the reactor is 8~50wt%; the alkaline aqueous solution is an aqueous solution with an alkali concentration of 5~20wt%, and the alkali is sodium hydroxide or potassium hydroxide. The gas-liquid-solid three-phase catalytic oxidation reactor is a slurry bed or a fixed bed. When the reaction is carried out in a fixed bed, the gas and liquid phases in the reactor are operated in an upward co-current, downward co-current, or counter-current operation. When the reaction is carried out in a slurry bed, the concentration of the catalyst in the reactor is 2~25 g / L.