Method for efficiently preparing ethyl chrysanthemate by using Beta / CuCl nano molecular sieve catalyst
By using the Beta/CuCl nanomolecular sieve catalyst in the production of ethyl chrysanthemate, the problems of high production cost and limited output in the existing technology have been solved, and efficient, safe and environmentally friendly preparation of ethyl chrysanthemate has been achieved, improving the industry. competitiveness and environmental performance.
Patent Information
- Application Number
- CN202411462133.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-18
- Publication Date
- 2025-01-21
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The existing ethyl chrysanthemum production technology has problems such as high production costs, limited production, insufficient market demand and great environmental impact, which has led to the problems of instability in supply and high costs in the sanitary pesticide industry and the anti-novel coronavirus pharmaceutical industry.
Using Beta/CuCl nanomolecular sieve catalyst, through an improved chemical reaction process, including diazotization reaction in an acidic environment, and using heptane as an organic solvent to facilitate the separation process, combined with adsorption column dehydration treatment, the reaction efficiency and yield are improved , and realize the reusability of the catalyst.
It significantly improves the yield and reaction efficiency of ethyl chrysanthemate, reduces production costs, reduces environmental pollution, achieves catalyst recyclability, and improves the safety and environmental protection of the entire production process.
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Figure CN119330826A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for efficiently preparing ethyl chrysanthemate by utilizing a Beta / CuCl nano molecular sieve catalyst. Background Art
[0002] Chrysanthemic acid ethyl ester, chemical name is 2,2-dimethyl-3-(2-methylprop-1-en-1-yl) cyclopropanecarboxylic acid ethyl ester, is an important organic compound, widely used in many fields such as medicine, pesticides and spices. As the main intermediate for the production of the first chrysanthemic acid series of sanitary insecticides, it plays an important role in the sanitary insecticide market and international competition. At present, only a few countries in the world can produce chrysanthemic acid ethyl ester, and its production capacity and cost directly affect the competitiveness of the domestic sanitary insecticide market and foreign competitive products.
[0003] During the preparation process, chrysanthemic acid ethyl ester can be synthesized by cyclization reaction of ethyl diazoacetate and octene in the presence of an organic amine catalyst. This synthesis method has the advantages of relatively low toxicity, less production wastewater and smaller molecular weight, but its production cost is high and its output is limited, resulting in insufficient market demand, limited annual output, and even supply interruption, which has an unstable impact on the market. Therefore, both the sanitary insecticide industry and the anti-new coronavirus pharmaceutical industry are in urgent need of increasing the output of chrysanthemic acid ethyl ester and reducing production costs.
[0004] Therefore, although the production technology of chrysanthemic acid ethyl ester is mature, some issues still need to be paid attention to in the production process, such as the control of raw material costs, the treatment of by-products, energy consumption and waste emissions in the production process. In addition, with the intensification of market competition, enterprises need to improve product quality and production efficiency while reducing production costs to maintain competitiveness. In the context of increasingly stringent environmental regulations, it is also necessary to continuously optimize production processes and reduce the impact on the environment. Summary of the invention
[0005] In order to solve the above technical problems, the present invention provides a method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst:
[0006] Step 1: first dispersing and dissolving glycine ethyl ester hydrochloride in water, adding heptane, adding acid solution and stirring under ice water bath condition, after it is completely dissolved, adding Beta / CuCl nano molecular sieve catalyst, continuing stirring for 10 to 15 minutes, slowly dropping sodium nitrite aqueous solution at a speed of 400 to 800 r / min for uniform mixing, continuing stirring and reacting for a period of time after the dropwise addition is completed, and then stopping, filtering, passing the filtrate into an adsorption column to remove water, collecting and washing the filtrate to obtain an ethyl diazoacetate dispersion;
[0007] The Beta / CuCl nanomolecular sieve catalyst provides a suitable acidic environment and active sites, while CuCl helps to stabilize the intermediates, thereby promoting the formation of diazo compounds;
[0008] The Beta / CuCl nano-molecular sieve catalyst recovered by filtration can be dried and then used in the next step;
[0009] Step 2: octadecene is mixed with Beta / CuCl nanomolecular sieve catalyst, and the reaction system is heated to 90°C to 95°C under constant temperature stirring conditions. While maintaining this temperature, the previously prepared ethyl diazoacetate dispersion is added dropwise. After the addition is completed, the reaction is continued under insulation conditions for 30 to 120 minutes. After the reaction is completed, ethyl chrysanthemate is purified to remove impurities and unreacted raw materials in the reaction system, and the organic solvent collected during the purification process is reused in step 1;
[0010] Wherein, under the catalytic action of the Beta / CuCl nano molecular sieve catalyst, ethyl diazoacetate and octene undergo a cycloaddition reaction to generate the target product ethyl chrysanthemate, and the catalyst can be reused.
[0011] Furthermore, in step 1, the acid solution is a citric acid aqueous solution with a solute mass fraction of 5% to 15%.
[0012] Furthermore, in step 1, the raw materials are calculated by mass ratio as follows: glycine ethyl hydrochloride: water: heptane: acid solution: Beta / CuCl nanomolecular sieve catalyst: sodium nitrite = 1: 1.4-1.8: 1-1.3: 0.3-0.4: 0.02-0.025: 0.5-0.6.
[0013] Furthermore, in step 2, the raw materials are calculated by mass ratio of ethyl diazoacetate prepared in step 1:octadecene:Beta / CuCl nano molecular sieve catalyst=1:1.5-1.8:0.025-0.03.
[0014] Furthermore, in step 1, the adsorption column is composed of a combination of two or more of molecular sieves, silica gel, anhydrous calcium sulfate, anhydrous magnesium sulfate, anhydrous sodium sulfate and activated alumina.
[0015] Furthermore, in step 2, during the heating and heat preservation stages, the components vaporized after being heated in the reaction system are synchronously condensed and refluxed.
[0016] Furthermore, in step 2, after the reaction is completed, the obtained reaction system is cooled, filtered and the Beta / CuCl nanomolecular sieve catalyst is recovered, and then evaporated to leave the crude chrysanthemic acid ethyl ester product, which is subjected to negative pressure distillation, and the main fraction is collected as the target product chrysanthemic acid ethyl ester, wherein during the evaporation process, the organic solvent vaporized by heat is condensed and collected.
[0017] Furthermore, in step 2, the crude chrysanthemic acid ethyl ester product is subjected to negative pressure distillation, and the main fraction is collected as the target product chrysanthemic acid ethyl ester.
[0018] Furthermore, the preparation method of the Beta / CuCl nanomolecular sieve catalyst comprises the following steps:
[0019] Step 1: Mix aluminum oxide and tetraethylammonium hydroxide solution, and stir magnetically at a speed of 500 r / min for 30 minutes to completely dissolve the aluminum oxide. The mass ratio of aluminum oxide to tetraethylammonium hydroxide solution is 1:20-50.
[0020] Step 2: Add the mixed solution to white carbon black, mix well, and dry at 70° C. for 5-8 hours to obtain a mixture, wherein the mass ratio of aluminum oxide to white carbon black is 1:50-300;
[0021] Step 3: Grind the mixture and transfer it into an open glass vessel, then transfer it into a hydrothermal reactor liner, add 4-20 mL of deionized water into the hydrothermal reactor liner, and prevent water outside the glass vessel from entering the glass vessel; adjust the hydrothermal reactor to 160-180° C. under steam-assisted conditions, and crystallize the mixture for a period of time to obtain a crystalline product;
[0022] Step 4: After the crystalline product is naturally cooled to room temperature, it is washed twice and then dried, and calcined at 500-600° C. in an air atmosphere for 12 hours to obtain a Beta nano-molecular sieve with high crystallinity.
[0023] Step 5: Solid grind cuprous chloride, cysteine and Beta nanomolecular sieve for 30-60 minutes, with a mass ratio of cuprous chloride: cysteine: Beta nanomolecular sieve = 1: 0.8-2: 4-10. The ground sample is calcined at 350-450° C. for 3-5 hours in an inert gas atmosphere to obtain a Beta / CuCl nanomolecular sieve catalyst.
[0024] The beneficial effect of the present invention is to improve the chemical reaction process, which achieves significant improvement in efficiency and safety in multiple key links. In the first stage of the diazotization reaction, by selecting heptane as the organic solvent, the present scheme ensures that the organic phase and the aqueous phase can be completely separated after the reaction, and this strategy greatly facilitates the subsequent separation process. Through further dehydration treatment of the adsorption column, we ensure that the ethyl diazoacetate entering the next stage is almost free of water. This improvement not only improves the reaction efficiency and yield, but also enhances the safety of the entire process.
[0025] In step one, the introduction of the Beta / CuCl nanomolecular sieve catalyst provides an ideal acidic environment and active sites for the diazotization reaction. The CuCl component plays a key role in stabilizing the reaction intermediates, effectively promoting the formation of diazo compounds, thereby increasing the yield. The unique pore structure of the Beta molecular sieve plays a positive role in regulating the diffusion of reactants and products, further improving the reaction rate and selectivity. In step two, the acidic properties and pore structure of the catalyst once again provide a suitable environment for the reaction. CuCl, as an active component, helps stabilize the metal carbene intermediates, thereby promoting the reaction and increasing the reaction rate and selectivity. At the same time, the use of the catalyst also helps to reduce the reaction temperature, making the entire reaction process more efficient.
[0026] In addition, a significant advantage of the present invention is the recyclability of the catalyst. The Beta / CuCl nanomolecular sieve catalyst recovered by filtration can be recycled, which not only reduces production costs, but also reduces environmental pollution, reflecting the design concept of green chemistry. In summary, the present invention optimizes the chemical reaction efficiency through innovative chemical reaction design and efficient use of catalysts, provides new possibilities for technological progress in related fields, and shows significant advantages in environmental protection and economy. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 A flow chart of a method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst. DETAILED DESCRIPTION
[0028] A method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst:
[0029] Step 1: first dispersing and dissolving glycine ethyl ester hydrochloride in water, adding heptane, adding acid solution and stirring under ice water bath condition, after it is completely dissolved, adding Beta / CuCl nano molecular sieve catalyst, continuing stirring for 10 to 15 minutes, slowly dropping sodium nitrite aqueous solution at a speed of 400 to 800 r / min for uniform mixing, continuing stirring and reacting for a period of time after the dropwise addition is completed, and then stopping, filtering, passing the filtrate into an adsorption column to remove water, collecting and washing the filtrate to obtain an ethyl diazoacetate dispersion;
[0030] The Beta / CuCl nanomolecular sieve catalyst provides a suitable acidic environment and active sites, while CuCl helps to stabilize the intermediates, thereby promoting the formation of diazo compounds;
[0031] The Beta / CuCl nano-molecular sieve catalyst is filtered, recovered, dried, and then used in the next step;
[0032] Step 2: octadecene is mixed with Beta / CuCl nanomolecular sieve catalyst, and the reaction system is heated to 90°C to 95°C under constant temperature stirring conditions. While maintaining this temperature, the previously prepared ethyl diazoacetate dispersion is added dropwise. After the addition is completed, the reaction is continued under insulation conditions for 30 to 120 minutes. After the reaction is completed, ethyl chrysanthemate is purified to remove impurities and unreacted raw materials in the reaction system, and the organic solvent collected during the purification process is reused in step 1;
[0033] Wherein, under the catalytic action of the Beta / CuCl nano molecular sieve catalyst, ethyl diazoacetate and octene undergo a cycloaddition reaction to generate the target product ethyl chrysanthemate, and the catalyst can be reused.
[0034] Wherein, in step 1, the acid solution is a citric acid aqueous solution with a solute mass fraction of 5% to 15%.
[0035] Among them, the raw materials in step 1 are calculated by mass ratio as follows: glycine ethyl hydrochloride: water: heptane: acid solution: Beta / CuCl nanomolecular sieve catalyst: sodium nitrite = 1: 1.4-1.8: 1-1.3: 0.3-0.4: 0.02-0.025: 0.5-0.6.
[0036] Among them, the raw materials in step 2 are calculated by mass ratio, and the whole batch of diazo liquid that can be recovered in step 1: octadecene: Beta / CuCl nano-molecular sieve catalyst = 1: 1.5-1.8: 0.025-0.03.
[0037] Wherein, in step 1, the adsorption column is composed of a combination of two or more of molecular sieve, silica gel, anhydrous calcium sulfate, anhydrous magnesium sulfate, anhydrous sodium sulfate and activated alumina.
[0038] Among them, in step 2, during the heating and insulation stages, the components vaporized after being heated in the reaction system are synchronously condensed and refluxed.
[0039] Among them, in step 2, after the reaction is completed, the obtained reaction system is cooled, filtered and recovered to recover the Beta / CuCl nanomolecular sieve catalyst, and then evaporated to leave the crude chrysanthemic acid ethyl ester product, which is subjected to negative pressure distillation, and the main fraction is collected as the target product chrysanthemic acid ethyl ester, wherein during the evaporation process, the organic solvent vaporized by heat is condensed and collected.
[0040] Wherein, in step 2, the crude chrysanthemic acid ethyl ester product is subjected to negative pressure distillation, and the main fraction is collected as the target product chrysanthemic acid ethyl ester.
[0041] Wherein, the preparation method of the Beta / CuCl nanomolecular sieve catalyst comprises the following steps:
[0042] Step 1: Mix aluminum oxide and tetraethylammonium hydroxide solution, and stir magnetically at a speed of 500 r / min for 30 minutes to completely dissolve the aluminum oxide. The mass ratio of aluminum oxide to tetraethylammonium hydroxide solution is 1:20-50.
[0043] Step 2: Add the mixed solution to white carbon black, mix well, and dry at 70° C. for 5-8 hours to obtain a mixture, wherein the mass ratio of aluminum oxide to white carbon black is 1:50-300;
[0044] Step 3: Grind the mixture and transfer it into an open glass vessel, then transfer it into a hydrothermal reactor liner, add 4-20 mL of deionized water into the hydrothermal reactor liner, and prevent water outside the glass vessel from entering the glass vessel; adjust the hydrothermal reactor to 160-180° C. under steam-assisted conditions, and crystallize the mixture for a period of time to obtain a crystalline product;
[0045] Step 4: After the crystalline product is naturally cooled to room temperature, it is washed twice and then dried, and calcined at 500-600° C. in an air atmosphere for 12 hours to obtain a Beta nano-molecular sieve with high crystallinity.
[0046] Step 5: Solid grind cuprous chloride, cysteine and Beta nanomolecular sieve for 30-60 minutes, with a mass ratio of cuprous chloride: cysteine: Beta nanomolecular sieve = 1: 0.8-2: 4-10. The ground sample is calcined at 350-450° C. for 3-5 hours in an inert gas atmosphere to obtain a Beta / CuCl nanomolecular sieve catalyst.
[0047] Example 1
[0048] Step 1: First, 200g of glycine ethyl ester hydrochloride is dispersed and dissolved in 160g of water, and then 200g of heptane is added, and then 60g of 5% citric acid solution is added and stirred in an ice-water bath. After it is completely dissolved, 4g of Beta / CuCl nano molecular sieve catalyst is added, and stirring is continued for 15min. Then, 251g of an aqueous solution containing 100g of sodium nitrite is slowly added dropwise at a speed of 400r / min for uniform mixing. After the dropwise addition is completed, stirring and reacting is continued for a period of time and then stopped. After filtering and recovering the Beta / CuCl nano molecular sieve catalyst, the mixture is allowed to stand for stratification at 10°C, and the organic phase after stratification is added to 100mL of deionized water, and stirred and washed at 10°C for 20 minutes, and then allowed to stand for stratification again. The separated organic phase is passed into an adsorption column (made of molecular sieve and silica gel) to remove moisture to obtain an ethyl diazoacetate dispersion. The composition of the ethyl diazoacetate dispersion is analyzed by gas chromatography, and the ethyl diazoacetate yield is 97%, which is stored at 10°C for standby use.
[0049] Step 2: Mix 350g of octadecene with 4g of Beta / CuCl nanomolecular sieve catalyst, heat the reaction system to 90°C under constant temperature stirring conditions, add the previously prepared ethyl diazoacetate dispersion dropwise while maintaining this temperature, and continue to react for 30 minutes under insulation conditions after the addition is completed. During the heating and insulation stages, the components that are vaporized after heating in the reaction system are synchronously condensed and refluxed. After the reaction is completed, the obtained reaction system is cooled and filtered to recover the Beta / CuCl nanomolecular sieve catalyst. The filtrate is heated to 80-90° C. under vacuum at -0.08 to -0.09 for evaporation. During the evaporation, the organic solvent from the ethyl diazoacetate dispersion is condensed and collected sufficiently. The crude chrysanthemic acid ethyl ester product left by the evaporation is heated to 130° C. under vacuum at -0.1 MPa for rectification and separation. The main fraction is collected as the target product chrysanthemic acid ethyl ester with a purity of 97.5.0% and a yield of 89.2% (the number of moles of the product ethyl diazoacetate in the dispersion / the number of moles of glycine ethyl hydrochloride in the raw material×100%, the same below).
[0050] During the evaporation process, the organic solvent vaporized by heat is condensed and collected, and the collected organic solvent is reused in step one.
[0051] Wherein, under the catalytic action of the Beta / CuCl nano molecular sieve catalyst, ethyl diazoacetate and octene undergo a cycloaddition reaction to generate the target product ethyl chrysanthemate, and the catalyst can be reused.
[0052] The preparation method of Beta / CuCl nano molecular sieve catalyst is as follows:
[0053] Step 1: Mix 0.1g of aluminum oxide with 5g of tetraethylammonium hydroxide solution, and stir magnetically at a speed of 500r / min for 30min to completely dissolve the aluminum oxide.
[0054] Step 2: Add 5g of white carbon black to the mixed solution, mix well, and dry at 70°C for 5 hours to obtain a mixture. Step 3: Grind the mixture and transfer it into an open glass vessel, then transfer it into the lining of a hydrothermal reactor. Add 8mL of deionized water to the lining of the hydrothermal reactor, and prevent water outside the glass vessel from entering the glass vessel; under steam-assisted conditions, adjust the hydrothermal reactor to 165°C and crystallize for 12 hours to obtain a crystalline product;
[0055] Step 4: The crystalline product is naturally cooled to room temperature, washed twice and dried, and finally calcined at 550° C. in an air atmosphere for 12 hours to obtain a Beta nano-molecular sieve with high crystallinity.
[0056] Step 5: Solid-grind 1 g of cuprous chloride, 1.5 g of cysteine and 4 g of Beta nanomolecular sieve for 60 min. The ground sample is calcined at 450° C. for 5 hours in a nitrogen atmosphere to obtain a Beta / CuCl nanomolecular sieve catalyst.
[0057] Example 2
[0058] Step 1: First, 200g of glycine ethyl ester hydrochloride is dispersed and dissolved in 170g of water, and then 220g of heptane is added, and then 65g of 10% citric acid solution is added and stirred under ice-water bath conditions. After it is completely dissolved, 4.5g of Beta / CuCl nano molecular sieve catalyst is added, and stirring is continued for 15min. Then, 285g of an aqueous solution containing 115g of sodium nitrite is slowly dripped, and the rotation speed is 400r / min for uniform mixing. After the dropwise addition is completed, stirring and reacting is continued for a period of time and then stopped. After filtering and recovering the Beta / CuCl nano molecular sieve catalyst, the mixture is allowed to stand at 10°C for stratification, and the organic phase after stratification is added to 100mL of deionized water, and stirred and washed at 10°C for 20 minutes, and then allowed to stand again for stratification. The separated organic phase is passed into an adsorption column (made of molecular sieve and silica gel) to remove moisture to obtain ethyl diazoacetate dispersion. The composition of the ethyl diazoacetate dispersion is analyzed by gas chromatography, and the yield of ethyl diazoacetate is 98.2%, which is stored at 10°C for standby use.
[0059] Step 2: 358g of octadecene is mixed with 5.5g of Beta / CuCl nanomolecular sieve catalyst, and the reaction system is heated to 90°C under constant temperature stirring conditions. While maintaining this temperature, the previously prepared ethyl diazoacetate dispersion is added dropwise. After the addition is completed, the reaction is continued under insulation conditions for 30 minutes. During the heating and insulation stages, the components vaporized after heating in the reaction system are synchronously condensed and refluxed. After the reaction is completed, the obtained reaction system is cooled, and the Beta / CuCl nanomolecular sieve catalyst is filtered and recovered. The filtrate is heated to 90°C under vacuum-0.08 and evaporated. During the evaporation process, the organic solvent from the ethyl diazoacetate dispersion is condensed and collected fully, and the crude chrysanthemum acid ethyl ester product left by the evaporation is heated to 135°C under vacuum-0.1MPa for rectification and separation. The main fraction is collected as the target product chrysanthemum acid ethyl ester with a purity of 98.5% and a yield of 89.8%.
[0060] During the evaporation process, the organic solvent vaporized by heat is condensed and collected, and the collected organic solvent is reused in step one.
[0061] Wherein, under the catalytic action of the Beta / CuCl nano molecular sieve catalyst, ethyl diazoacetate and octene undergo a cycloaddition reaction to generate the target product ethyl chrysanthemate, and the catalyst can be reused.
[0062] The preparation method of the Beta / CuCl nanomolecular sieve catalyst is shown in Example 1.
[0063] Example 3
[0064] Step 1: First, 200g of glycine ethyl ester hydrochloride is dispersed and dissolved in 180g of water, and then 250g of heptane is added, and then 80g of 5% citric acid solution is added and stirred under ice-water bath conditions. After it is completely dissolved, 5g of Beta / CuCl nano molecular sieve catalyst is added, and stirring is continued for 15min. Then, 295g of an aqueous solution containing 120g of sodium nitrite is slowly added dropwise at a speed of 400r / min for uniform mixing. After the dropwise addition is completed, stirring and reacting is continued for a period of time and then stopped. After filtering and recovering the Beta / CuCl nano molecular sieve catalyst, the mixture is allowed to stand at 10°C for stratification, and the organic phase after stratification is added to 100mL of deionized water, and stirred and washed at 10°C for 20 minutes, and then allowed to stand for stratification again. The separated organic phase is passed into an adsorption column (made of molecular sieve and silica gel) to remove moisture to obtain an ethyl diazoacetate dispersion. The composition of the ethyl diazoacetate dispersion is analyzed by gas chromatography to obtain an ethyl diazoacetate yield of 98.5%, which is stored at 10°C for standby use.
[0065] Step 2: 358g of octadecene is mixed with 5.8g of Beta / CuCl nanomolecular sieve catalyst, and the reaction system is heated to 90°C under constant temperature stirring conditions. While maintaining this temperature, the previously prepared ethyl diazoacetate dispersion is added dropwise. After the dropwise addition is completed, the reaction is continued under insulation conditions for 30 minutes. During the heating and insulation stages, the components vaporized after heating in the reaction system are synchronously condensed and refluxed. After the reaction is completed, the resulting reaction system is cooled, and the Beta / CuCl nanomolecular sieve catalyst is filtered and recovered. The filtrate is heated to 90°C under vacuum -0.08 and evaporated. During the evaporation process, the organic solvent from the ethyl diazoacetate dispersion is condensed and collected fully, and the crude chrysanthemum acid ethyl ester product left by the evaporation is heated to 135°C under vacuum -0.1MPa for rectification and separation. The main fraction is collected as the target product chrysanthemum acid ethyl ester with a purity of 99.1% and a yield of 90%.
[0066] During the evaporation process, the organic solvent vaporized by heat is condensed and collected, and the collected organic solvent is reused in step one.
[0067] Wherein, under the catalytic action of the Beta / CuCl nano molecular sieve catalyst, ethyl diazoacetate and octene undergo a cycloaddition reaction to generate the target product ethyl chrysanthemate, and the catalyst can be reused.
[0068] The preparation method of the Beta / CuCl nanomolecular sieve catalyst is shown in Example 1.
[0069] Comparative Example 1
[0070] Step 1: Add 275 grams of glycine ethyl hydrochloride, 250 mL of deionized water, 450 mL of tert-amyl methyl ether and 100 mL of n-hexane to the reaction bottle in sequence. Under continuous stirring, first adjust the temperature of the stirring system to 10°C by an ice-water bath, and add sodium nitrite aqueous solution (156 g of sodium nitrite is dissolved in 245 mL of deionized water) dropwise thereto under insulation and continuous stirring. After the addition is complete, continue to add 35 g of dilute sulfuric acid aqueous solution with a solute mass fraction of 8% dropwise thereto under insulation at 10°C and continuous stirring. After the addition of the dilute sulfuric acid aqueous solution, continue to keep warm and stir the reaction at 10°C for 45 minutes, stop stirring, let stand at 10°C to separate the layers, add the separated organic phase into 100 mL of deionized water, stir and wash at 10°C for 10 minutes, let stand again at 10°C to separate the layers, use the separated organic phase as ethyl diazoacetate dispersion, analyze the composition of ethyl diazoacetate dispersion by gas chromatography, and obtain a ethyl diazoacetate yield of 92.5%, and store at 10°C for later use.
[0071] Step 2: 650 grams of octadecene, 2.4 grams of catalyst triethylenediamine, and 0.01 grams of polymerization inhibitor are put into another reaction bottle, and heated to 103°C and kept warm under continuous stirring and condensation reflux, and then the ethyl diazoacetate dispersion obtained in step 1 is added dropwise thereto, and the reaction is continued for 30 minutes of insulation and stirring after the addition is completed. After the reaction is completed, the obtained reaction system is added to a sufficient amount of cold water, and the organic catalyst enters the water phase to achieve separation, and then the organic phase after stratification is heated to 100°C under vacuum -0.08 for steam removal. During the steam removal process, the organic solvent from the ethyl diazoacetate dispersion is condensed and collected sufficiently, and the crude chrysanthemum acid ethyl ester product left by the steam removal is heated to 130°C under vacuum -0.1MPa for rectification and separation. The main fraction is collected as the target product chrysanthemum acid ethyl ester, with a purity of 92.5% and a yield of 83.4%.
Claims
1. A method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst, characterized in that: The following steps are included: Step 1: first dispersing and dissolving glycine ethyl ester hydrochloride in water, adding heptane, adding acid solution and stirring under ice water bath condition, after it is completely dissolved, adding Beta / CuCl nano molecular sieve catalyst, continuing stirring for 10 to 15 minutes, slowly dropping sodium nitrite aqueous solution at a speed of 400 to 800 r / min for uniform mixing, continuing stirring and reacting for a period of time after the dropwise addition is completed and then stopping, filtering it, standing at 10° C. to 15° C. for stratification, adding the organic phase after stratification into deionized water, stirring and washing for 20 to 40 minutes, standing again for stratification, passing the separated organic phase into an adsorption column to remove water, and obtaining an ethyl diazoacetate dispersion; The Beta / CuCl nano-molecular sieve catalyst is filtered, recovered, dried, and then used in the next step; Step 2: octadecene is mixed with Beta / CuCl nanomolecular sieve catalyst, and the reaction system is heated to 90°C to 95°C under constant temperature stirring conditions. While maintaining this temperature, the previously prepared ethyl diazoacetate dispersion is added dropwise. After the addition is completed, the reaction is continued under insulation conditions for 30 to 120 minutes. After the reaction is completed, ethyl chrysanthemate is purified to remove impurities and unreacted raw materials in the reaction system, and the organic solvent collected during the purification process is reused in step 1.
2. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst as claimed in claim 1, characterized in that: The preparation method of the Beta / CuCl nano molecular sieve catalyst comprises the following steps: Step 1: Mix aluminum oxide and tetraethylammonium hydroxide solution, and stir magnetically at a speed of 500 r / min for 30 minutes to completely dissolve the aluminum oxide. The mass ratio of aluminum oxide to tetraethylammonium hydroxide solution is 1:20-50. Step 2: Add the mixed solution to white carbon black, mix well, and dry at 70° C. for 5-8 hours to obtain a mixture, wherein the mass ratio of aluminum oxide to white carbon black is 1:50-300; Step 3: Grind the above mixture and transfer it into an open glass vessel, then transfer it into the lining of a hydrothermal reactor, add 4 to 20 mL of deionized water into the lining of the hydrothermal reactor, and prevent water outside the glass vessel from entering the glass vessel; adjust the hydrothermal reactor to 160 to 180° C. under steam-assisted conditions, and crystallize the mixture for 8 to 20 hours to obtain a crystalline product; Step 4: After the crystalline product is naturally cooled to room temperature, it is washed twice and dried, and calcined at 500-600° C. in an air atmosphere for 12 hours to obtain a Beta nano-molecular sieve with high crystallinity. Step 5: Solid grind cuprous chloride, cysteine and Beta nanomolecular sieve for 30-60 minutes, with a mass ratio of cuprous chloride: cysteine: Beta nanomolecular sieve = 1: 0.8-2: 4-10. The ground sample is calcined at 350-450° C. for 3-5 hours in an inert gas atmosphere to obtain a Beta / CuCl nanomolecular sieve catalyst.
3. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst as claimed in claim 1, characterized in that: In step 1, the acid solution is a citric acid aqueous solution with a solute mass fraction of 5% to 15%.
4. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst as claimed in claim 1, characterized in that: The raw materials in step 1 are calculated by mass ratio as follows: glycine ethyl hydrochloride: water: heptane: acid solution: Beta / CuCl nanomolecular sieve catalyst: sodium nitrite = 1: 1.4-1.8: 1-1.3: 0.3-0.4: 0.02-0.025: 0.5-0.
6.
5. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst as claimed in claim 1, characterized in that: The raw materials in step 2 are calculated by mass ratio: ethyl diazoacetate obtained in step 1: octadecene: Beta / CuCl nanomolecular sieve catalyst = 1: 1.5 ~ 1.8: 0.025 ~ 0.
03.
6. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst as claimed in claim 1, characterized in that: In step 1, the adsorption column is composed of a combination of two or more of molecular sieve, silica gel, anhydrous calcium sulfate, anhydrous magnesium sulfate, anhydrous sodium sulfate and activated alumina.
7. The method for preparing ethyl chrysanthemate according to claim 1, wherein In step 2, during the heating and heat preservation stages, the components vaporized after being heated in the reaction system are synchronously condensed and refluxed.
8. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nanomolecular sieve catalyst as claimed in claim 1, characterized in that: In step 2, after the reaction is completed, the obtained reaction system is cooled, filtered and the Beta / CuCl nanomolecular sieve catalyst is recovered, and then evaporated to leave the crude chrysanthemic acid ethyl ester product, which is subjected to negative pressure distillation, and the main fraction is collected as the target product chrysanthemic acid ethyl ester, wherein during the evaporation process, the organic solvent vaporized by heat is condensed and collected.
9. The method for efficiently preparing ethyl chrysanthemate using Beta / CuCl nano molecular sieve catalyst as claimed in claim 8, characterized in that: In step 2, the crude chrysanthemic acid ethyl ester product is subjected to negative pressure distillation, and the main fraction is collected as the target product chrysanthemic acid ethyl ester.
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