Efficient synthesis process of fludioxonil intermediate

Abstract

The invention discloses an efficient synthesis process of a fludioxonil intermediate, and belongs to the technical field of organic synthesis.The efficient synthesis process comprises the steps that pores of supported biochar powder are filled with nanometer aluminum oxide and nanometer cerium oxide, then metal oxide biochar powder is modified through a silane coupling agent, Pd-MOF is grafted to the modified biochar powder, and the modified biochar powder is modified through a silane coupling agent to obtain the fludioxonil intermediate. The three-dimensional space structure of MOF is utilized to provide more active sites for palladium, the catalytic efficiency of palladium can be improved, fluorine ions are promoted to replace chloride ions, efficient reaction is facilitated, the porous structure in the composite charcoal powder can improve the loading rate of nano aluminum oxide and nano cerium oxide, and the catalytic activity of palladium is improved. Lewis acid sites on the surfaces of the nano aluminum oxide and the nano cerium oxide can adsorb hydrogen fluoride molecules, the hydrogen fluoride molecules are enriched in composite catalyst powder in a physical adsorption and chemical combination mode through the nano aluminum oxide and the nano cerium oxide, then the hydrogen fluoride and excessive potassium fluoride generate potassium bifluoride, and the thermal decomposition reaction rate of the potassium bifluoride is inhibited.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and specifically relates to an efficient synthesis process of a fludioxonil intermediate. Background Art

[0002] Fludioxonil is a broad-spectrum and highly efficient non-systemic benzopyrrole fungicide, which exerts its effect by inhibiting the histidine kinase activity in the fungal signal transduction pathway and is widely used in the fields of crop disease control and post-harvest preservation of fruits and vegetables. Its core structure is 3-(2,2-difluoro-1,3-benzodioxol-4-yl)-1H-pyrrole-2-carbonitrile, and the synthesis efficiency of the key intermediate 2,2-difluorobenzodioxol-4-amine (DFBD) directly determines the cost and industrial feasibility of the final product. In traditional processes, the synthesis of DFBD usually uses catechol as the starting material and is prepared through multiple steps such as epoxidation, fluorination, nitration, and reduction.

[0003] The Chinese invention patent application with the publication number CN101851225B discloses a synthesis method of a fludioxonil intermediate 4-formyl-2,2-difluorobenzodioxole. Using cheap and easily available o-cresol as the starting material, 3-methylsalicylaldehyde is obtained through ortho-directed formylation. 3-Methylsalicylaldehyde is converted into 3-methylcatechol through the Dakin reaction, and then directly reacts with dichloromethane or dibromomethane without separation and purification to form 4-methylbenzodioxole, and then undergoes three steps of chlorination, fluorination, and oxidation to form 4-formyl-2,2-difluorobenzodioxole, greatly reducing the production cost, avoiding the use of chlorine gas, and reducing the risk of environmental pollution.

[0004] In the synthesis of the intermediate 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxolene, as a key step, the fluorination reaction needs to introduce two fluorine atoms at the C-2 and C-2' positions of the benzodioxole skeleton. However, potassium bifluoride that provides fluorine atoms is prone to thermal decomposition during the reaction, releasing volatile HF, resulting in low fluorine atom utilization rate and affecting the reaction progress. Summary of the Invention

[0005] The purpose of the present invention is to provide an efficient synthesis process of a fludioxonil intermediate. By loading aluminum hydroxide and cerium hydroxide on the biochar precursor powder, then undergoing high-temperature dehydration to form aluminum oxide and cerium oxide, then grafting with Pd-MOF, and reducing the palladium ions to nano-palladium through reduction, and using the MOF spatial structure to uniformly load the nano-palladium on the composite biochar powder to obtain the composite catalyst powder, and then carrying out the synthesis reaction, the problem that potassium bifluoride is prone to decompose and release hydrogen fluoride at high temperature is solved, and the effects of reducing the emission of hydrogen fluoride gas and improving the utilization rate of fluorine atoms are achieved.

[0006] The object of the present invention can be achieved by the following technical solutions: An efficient synthesis process of a fludioxonil intermediate, comprising the following steps: Step 1: Depositing aluminum hydroxide and cerium hydroxide on the biochar precursor powder by aluminum chloride solution and cerium chloride solution to obtain a supported biochar powder.

[0007] Step 2: Dehydrating the supported biochar powder to obtain a metal oxide biochar powder, then modifying it with a silane coupling agent to obtain a modified biochar powder. A Pd-MOF is formed by a coordination bond between palladium ions and organic ligands, and the modified biochar powder and Pd-MOF are grafted together to obtain a composite biochar powder.

[0008] Step 3: Calcining the composite biochar powder at a high temperature to obtain a composite catalyst powder. Adding 4-dichloromethyl-2,2-dichlorobenzo[1,3]dioxole, potassium fluoride, potassium bifluoride, the composite catalyst powder and anhydrous sulfolane into a reaction kettle, and reacting for 8-9 h under the conditions of nitrogen and 90-100 °C to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole.

[0009] Further, the supported biochar powder is prepared by the following steps: Placing the sludge powder in a muffle furnace for calcination, then adding potassium acetate powder to form pores to obtain a biochar precursor powder. Then adding a 0.1 mol / L aluminum chloride solution, a 0.05 mol / L cerium chloride solution and the biochar precursor powder into a reaction kettle, adjusting the pH value to 5-6 with sodium hydroxide, stirring for 4-6 h, then adjusting the pH value to 7-8 with sodium hydroxide, stirring for 4-6 h, filtering, washing and drying to obtain the supported biochar powder.

[0010] Further, the dosage ratio of the sludge powder to the potassium acetate powder is 50-55 g: 70-80 g.

[0011] Further, the dosage ratio of the aluminum chloride solution, the cerium chloride solution and the biochar precursor powder is 200-300 mL: 200-300 mL: 10-15 g.

[0012] Further, the metal oxide biochar powder is prepared by the following steps: Placing the supported biochar powder in a tubular furnace, heating it to 300-320 °C at a rate of 5 °C / min in an air atmosphere, holding for 2-3 h, heating it to 500-520 °C in a nitrogen atmosphere, holding for 0.5-1 h, and cooling to room temperature to obtain the metal oxide biochar powder.

[0013] Further, the modified biochar powder is prepared by the following steps: Add KH-550, deionized water and dichloromethane into a reaction kettle, react for 2 - 3 h, then add metal oxide biochar powder, ethanol and ammonia water, and react for 5 - 6 h under the conditions of 70 - 80 °C and 500 - 800 r / min. Filter, wash and dry to obtain the modified biochar powder.

[0014] Furthermore, the dosage ratio of KH-550, deionized water, dichloromethane, metal oxide biochar powder, ethanol and ammonia water is: 3 - 5 mL : 50 - 60 mL : 90 - 100 mL : 10 - 15 g : 150 - 200 mL : 25 - 30 mL.

[0015] Furthermore, the composite biochar powder is prepared by the following steps: Add palladium chloride solution, 4,4'-bipyridine and ethylene glycol solution into a reaction kettle, react for 24 - 48 h under the conditions of 100 - 120 °C and 300 - 500 r / min, then add the modified biochar powder and N,N-dimethylformamide, and react for 8 - 9 h under the conditions of 80 - 90 °C and 500 - 800 r / min. Filter, wash and dry to obtain the composite biochar powder.

[0016] Furthermore, the dosage ratio of palladium chloride solution, 4,4'-bipyridine, ethylene glycol solution, modified biochar powder and N,N-dimethylformamide is: 20 - 30 mL : 15 - 20 g : 600 - 700 mL : 10 - 15 g : 300 - 400 mL.

[0017] Furthermore, the composite catalyst powder is prepared by the following steps: Place the composite biochar powder in a tubular furnace, heat it to 350 - 400 °C at a rate of 5 °C / min under a mixed atmosphere of argon and hydrogen, keep the temperature for reaction for 2 - 3 h, and cool to room temperature to obtain the composite catalyst powder.

[0018] Furthermore, the dosage ratio of 4-dichloromethyl-2,2-dichlorobenzo[1,3]dioxole, potassium fluoride, potassium bifluoride, composite catalyst powder and anhydrous sulfolane is: 30 - 32 g : 16 - 18 g : 2 - 3 g : 0.1 - 0.5 g : 50 - 100 mL.

[0019] The beneficial effects of the present invention: The composite catalyst powder in the present invention is prepared by filling nano-alumina and nano-ceria into the pores of the supported biochar powder, then modifying the metal oxide biochar powder with a silane coupling agent, grafting Pd-MOF onto the modified biochar powder to obtain a composite biochar powder, and then calcining it in a mixed atmosphere of hydrogen and argon at high temperature. During the calcination process, palladium ions are reduced to nano-palladium. The three-dimensional spatial structure of MOF provides more active sites for palladium, which can improve the catalytic efficiency of palladium, promote the substitution of fluoride ions for chloride ions, and is beneficial to the efficient progress of the reaction. The porous structure in the composite biochar powder can increase the loading rate of nano-alumina and nano-ceria, and the Lewis acid sites on the surfaces of nano-alumina and nano-ceria can adsorb hydrogen fluoride molecules. At the same time, the porous structure of the composite biochar powder can also adsorb part of the hydrogen fluoride. The two enrich hydrogen fluoride molecules in the composite catalyst powder through physical adsorption and chemical bonding, and then react with excessive potassium fluoride to generate potassium bifluoride, inhibiting the thermal decomposition reaction rate of potassium bifluoride, thereby improving the utilization rate of fluorine atoms in the reactants and the synthesis efficiency of the fludioxonil intermediate.

[0020] In the present invention, the metal oxide biochar powder is prepared by first calcining the sludge powder, then mixing it with potassium acetate powder and performing secondary calcination. The activation process of potassium acetate promotes the partial ablation of silicon dioxide and calcium carbonate crystals in the sludge powder. At the same time, the decomposition of potassium acetate generates carbon dioxide gas, which can produce a pore-forming effect to obtain a biochar precursor powder with a larger specific surface area. Then, aluminum chloride solution and cerium chloride solution are used to generate aluminum hydroxide and cerium hydroxide under alkaline conditions and deposit them on the biochar precursor powder. Then, it is heated in a tubular furnace in an air atmosphere for dehydration, so that nano-alumina and nano-ceria can be evenly distributed in the pores of the supported biochar powder. The increased specific surface area can improve the loading rate of nano-metal oxides and also increase the contact area with hydrogen fluoride. Specific Embodiments

[0021] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] Example 1: This example provides a high-efficiency synthesis process for the fludioxonil intermediate, including the following steps: S1: Wrap 52.5 g of dried sludge powder with tin foil, place it in a muffle furnace, heat it to 625 °C at a rate of 10 °C / min, hold for 1 h, cool to room temperature, then add 75 g of potassium acetate powder, mix evenly, and then put it back into the muffle furnace and heat it to 625 °C at a rate of 10 °C / min, hold for 1 h. During the activation process of potassium acetate, partial ablation of silicon dioxide and calcium carbonate crystals in the sludge powder is promoted. At the same time, a gasification reaction of potassium acetate occurs, producing a pore-forming effect and increasing the specific surface area. Wash it 4 times with a hydrochloric acid solution with a concentration of 0.1 mol / L, and dry it at 85 °C for 8 h to obtain the biochar precursor powder.

[0023] S2: Add 250 mL of aluminum chloride solution with a concentration of 0.1 mol / L and 250 mL of cerium chloride solution with a concentration of 0.05 mol / L to the reaction kettle, mix evenly, then add 12.5 g of the biochar precursor powder. First, adjust the pH value to 5 with sodium hydroxide solution, stir at 22 °C and 400 r / min for 5 h to deposit aluminum hydroxide on the biochar precursor powder, and then adjust the pH value to 7 with sodium hydroxide solution and stir for 5 h to deposit cerium hydroxide on the biochar precursor powder. Centrifuge and filter, wash the filter cake 4 times with deionized water, and dry it at 85 °C for 8 h to obtain the supported biochar powder.

[0024] S3: Place the supported biochar powder in a tubular furnace, heat it to 310 °C at a rate of 5 °C / min in an air atmosphere, hold for 2 h, then heat it to 510 °C in a nitrogen atmosphere and hold for 0.5 h. Aluminum hydroxide and cerium hydroxide dehydrate to form nano-aluminum oxide and nano-cerium oxide and fill the pores of the supported biochar powder, and reduce the contact area between the biochar and oxygen. Cool to room temperature to obtain the metal oxide biochar powder.

[0025] S4: Add 4 mL of silane coupling agent KH-550, 55 mL of deionized water and 95 mL of dichloromethane to the reaction kettle, react at 22 °C and 400 r / min for 2 h, then add 12.5 g of the metal oxide biochar powder, 175 mL of ethanol and 27 mL of ammonia water, and react at 75 °C and 650 r / min for 5 h to graft KH-550 onto the metal oxide biochar powder to form Si-O-C bonds. Cool to room temperature, filter, wash the filter cake 4 times alternately with absolute ethanol and deionized water, and dry it at 70 °C for 10 h to obtain the modified biochar powder.

[0026] S5: Add 25 mL of palladium chloride solution, 17.5 g of 4,4'-bipyridine, and 650 mL of ethylene glycol solution into a reaction kettle, react at 110 °C and 400 r / min for 36 h. Coordination bonds are formed between palladium ions and 4,4'-bipyridine as a ligand to generate Pd-MOF. Cool to room temperature, then add 12.5 g of modified biochar powder and 350 mL of N,N-dimethylformamide, react at 85 °C and 650 r / min for 8 h. Amino groups on the silane coupling agent KH-550 form coordination bonds with metal ions of Pd-MOF. Cool to room temperature, centrifuge and filter, wash the filter cake 4 times with ethylene glycol and deionized water respectively, and freeze-dry to obtain composite biochar powder.

[0027] S6: Place 12.5 g of composite biochar powder in a tubular furnace, heat it to 375 °C at a rate of 5 °C / min under a mixed atmosphere of argon and hydrogen, hold the reaction for 2 h. Nano-palladium particles are evenly distributed in the pores of the composite biochar. Cool to room temperature to obtain composite catalyst powder.

[0028] S7: Add 31 g of 4-dichloromethyl-2,2-dichlorobenzo[1,3]dioxole, 17 g of potassium fluoride, 2.5 g of potassium bifluoride, 0.3 g of composite catalyst powder, and 75 mL of anhydrous sulfolane into a reaction kettle, heat it to 95 °C under nitrogen protection and react for 8 h. Lewis acidic sites on the surfaces of alumina and cerium oxide can adsorb hydrofluoric acid molecules, and the porous structure of biochar provides more active sites, enabling hydrofluoric acid to be enriched inside the composite catalyst powder, and then promoting the reaction between hydrofluoric acid and excessive potassium fluoride to generate potassium bifluoride, improving the utilization rate of fluorine atoms. Cool to room temperature, filter, concentrate the filtrate under reduced pressure, and extract it 4 times with ethyl acetate. Evaporate ethyl acetate at 77 °C to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (the intermediate of fludioxonil).

[0029] Example 2: This example provides a high-efficiency synthesis process for the intermediate of fludioxonil, including the following steps: S1: Wrap 50 g of dried sludge powder with tin foil, put it into a muffle furnace, heat it to 600 °C at a speed of 10 °C / min, hold for 1 h, cool to room temperature, then add 70 g of potassium acetate powder, mix evenly, and then put it into the muffle furnace again, heat it to 600 °C at a speed of 10 °C / min, hold for 1 h. During the activation process of potassium acetate, the partial ablation of silica and calcium carbonate crystals in the sludge powder is promoted. At the same time, potassium acetate undergoes a gasification reaction, generating a pore-forming effect and increasing the specific surface area. Wash it 3 times with a hydrochloric acid solution with a concentration of 0.1 mol / L, and dry it at 80 °C for 8 h to obtain biochar precursor powder.

[0030] S2: Add 200 mL of aluminum chloride solution with a concentration of 0.1 mol / L and 200 mL of cerium chloride solution with a concentration of 0.05 mol / L into the reaction kettle, mix evenly, then add 10 g of biochar precursor powder. First, adjust the pH value to 5 with sodium hydroxide solution, stir at 20 °C and 300 r / min for 4 h to deposit aluminum hydroxide on the biochar precursor powder. Then, adjust the pH value to 7 with sodium hydroxide solution and stir for 4 h to deposit cerium hydroxide on the biochar precursor powder. Centrifuge and filter, wash the filter cake with deionized water 3 times, and dry at 80 °C for 8 h to obtain the supported biochar powder.

[0031] S3: Place the supported biochar powder in a tubular furnace, heat it to 300 °C at a rate of 5 °C / min in an air atmosphere, hold for 2 h, then heat it to 500 °C in a nitrogen atmosphere and hold for 0.5 h. Aluminum hydroxide and cerium hydroxide dehydrate to form nano-aluminum oxide and nano-cerium oxide and fill the pores of the supported biochar powder, and reduce the contact area between the biochar and oxygen. Cool to room temperature to obtain the metal oxide biochar powder.

[0032] S4: Add 3 mL of silane coupling agent KH-550, 50 mL of deionized water and 90 mL of dichloromethane into the reaction kettle, react at 20 °C and 300 r / min for 2 h, then add 10 g of metal oxide biochar powder, 150 mL of ethanol and 25 mL of ammonia water, react at 70 °C and 500 r / min for 5 h to graft KH-550 onto the metal oxide biochar powder to form Si-O-C bonds. Cool to room temperature, filter, wash the filter cake alternately with absolute ethanol and deionized water 3 times, and dry at 60 °C for 8 h to obtain the modified biochar powder.

[0033] S5: Add 20 mL of palladium chloride solution, 15 g of 4,4'-bipyridine and 600 mL of ethylene glycol solution into the reaction kettle, react at 100 °C and 300 r / min for 24 h to form a coordination bond between palladium ions and 4,4'-bipyridine as a ligand to generate Pd-MOF. Cool to room temperature, then add 10 g of modified biochar powder and 300 mL of N,N-dimethylformamide, react at 80 °C and 500 r / min for 8 h. The amino group on the silane coupling agent KH-550 forms a coordination bond with the metal ions of Pd-MOF. Cool to room temperature, centrifuge and filter, wash the filter cake with ethylene glycol and deionized water 3 times respectively, and freeze-dry to obtain the composite biochar powder.

[0034] S6: Place 10 g of the composite biochar powder in a tubular furnace, heat it to 350 °C at a rate of 5 °C / min in a mixed atmosphere of argon and hydrogen, hold for 2 h, and the nano-palladium particles are evenly distributed in the pores of the composite biochar. Cool to room temperature to obtain the composite catalyst powder.

[0035] S7: Add 30 g of 4 - dichloromethyl - 2,2 - dichlorobenzo[1,3]dioxole, 16 g of potassium fluoride, 2 g of potassium bifluoride, 0.1 g of composite catalyst powder, and 50 mL of anhydrous sulfolane into the reaction kettle. Under nitrogen protection, heat up to 90 °C and react for 8 h. The Lewis acidic sites on the surfaces of alumina and cerium oxide can adsorb hydrofluoric acid molecules, and the porous structure of biochar provides more active sites, enabling hydrofluoric acid to be enriched inside the composite catalyst powder. Then, it promotes the reaction between hydrofluoric acid and excessive potassium fluoride to generate potassium bifluoride, improving the utilization rate of fluorine atoms. Cool to room temperature, filter, concentrate the filtrate under reduced pressure, and extract with ethyl acetate 3 times. Evaporate and remove ethyl acetate at 75 °C to obtain 4 - dichloromethyl - 2,2 - difluorobenzo[1,3]dioxole (the intermediate of fludioxonil).

[0036] Example 3: This example provides a high - efficiency synthesis process for the intermediate of fludioxonil, which includes the following steps: S1: Wrap 55 g of dried sludge powder with tin foil, put it into a muffle furnace, heat up to 650 °C at a rate of 10 °C / min, keep it warm for 1.5 h, cool to room temperature, then add 80 g of potassium acetate powder, mix evenly, and then put it into the muffle furnace again, heat up to 650 °C at a rate of 10 °C / min, and keep it warm for 1.5 h. During the activation process of potassium acetate, it promotes the partial ablation of silicon dioxide and calcium carbonate crystals in the sludge powder. At the same time, potassium acetate undergoes a gasification reaction, generating a pore - forming effect and increasing the specific surface area. Wash it 5 times with a hydrochloric acid solution with a concentration of 0.1 mol / L, and dry it at 90 °C for 9 h to obtain biochar precursor powder.

[0037] S2: Add 300 mL of aluminum chloride solution with a concentration of 0.1 mol / L and 300 mL of cerium chloride solution with a concentration of 0.05 mol / L into the reaction kettle, mix evenly, then add 15 g of biochar precursor powder. First, adjust the pH value to 6 with sodium hydroxide solution, stir at 25 °C and 500 r / min for 6 h to deposit aluminum hydroxide on the biochar precursor powder. Then, adjust the pH value to 8 with sodium hydroxide solution and stir for 6 h to deposit cerium hydroxide on the biochar precursor powder. Centrifuge and filter, wash the filter cake 5 times with deionized water, and dry it at 90 °C for 9 h to obtain supported biochar powder.

[0038] S3: Place the supported biochar powder in a tube furnace, heat up to 320 °C at a rate of 5 °C / min in an air atmosphere, keep it warm and react for 3 h, then heat up to 520 °C in a nitrogen atmosphere and keep it warm for 1 h. Aluminum hydroxide and cerium hydroxide dehydrate to form nano - alumina and nano - cerium oxide and fill the pores of the supported biochar powder, and reduce the contact area between biochar and oxygen. Cool to room temperature to obtain metal - oxide biochar powder.

[0039] S4: Add 5 mL of silane coupling agent KH-550, 60 mL of deionized water, and 100 mL of dichloromethane into a reaction kettle, react for 3 h under the conditions of 25 °C and 500 r / min, then add 15 g of metal oxide biochar powder, 200 mL of ethanol, and 30 mL of ammonia water, react for 6 h under the conditions of 80 °C and 800 r / min, graft KH-550 onto the metal oxide biochar powder to form Si-O-C bonds, cool to room temperature, filter, wash the filter cake 5 times alternately with absolute ethanol and deionized water, and dry at 80 °C for 12 h to obtain the modified biochar powder.

[0040] S5: Add 30 mL of palladium chloride solution, 20 g of 4,4'-bipyridine, and 700 mL of ethylene glycol solution into a reaction kettle, react for 48 h under the conditions of 120 °C and 500 r / min, form a coordination bond between palladium ions and 4,4'-bipyridine as a ligand to generate Pd-MOF, cool to room temperature, then add 15 g of modified biochar powder and 400 mL of N,N-dimethylformamide, react for 9 h under the conditions of 90 °C and 800 r / min, form a coordination bond between the amino group on the silane coupling agent KH-550 and the metal ions of Pd-MOF, cool to room temperature, centrifuge and filter, wash the filter cake 5 times with ethylene glycol and deionized water respectively, and freeze-dry to obtain the composite biochar powder.

[0041] S6: Place 15 g of the composite biochar powder in a tubular furnace, heat it to 400 °C at a rate of 5 °C / min under a mixed atmosphere of argon and hydrogen, hold the reaction for 3 h, the nano-palladium particles are evenly distributed in the pores of the composite biochar, cool to room temperature to obtain the composite catalyst powder.

[0042] S7: Add 32 g of 4-dichloromethyl-2,2-dichlorobenzo[1,3]dioxole, 18 g of potassium fluoride, 3 g of potassium bifluoride, 0.5 g of the composite catalyst powder, and 100 mL of anhydrous sulfolane into a reaction kettle, heat it to 100 °C under nitrogen protection and react for 9 h. The Lewis acidic sites on the surfaces of alumina and ceria can adsorb hydrofluoric acid molecules, and the porous structure of the biochar provides more active sites, enabling hydrofluoric acid to be enriched inside the composite catalyst powder, and then promoting the reaction between hydrofluoric acid and excessive potassium fluoride to generate potassium bifluoride, improving the utilization rate of fluorine atoms. Cool to room temperature, filter, concentrate the filtrate under reduced pressure, and extract it 5 times with ethyl acetate, evaporate and remove ethyl acetate at 80 °C to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (the intermediate of fludioxonil).

[0043] Comparative Example 1: On the basis of Example 1, the composite catalyst powder in step S7 was removed, and the remaining steps remained unchanged to obtain 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole (fenpiclonil intermediate).

[0044] Comparative Example 2: On the basis of Example 1, the metal oxide biochar powder prepared in step S3 was used to replace the composite catalyst powder in step S7, and the remaining steps remained unchanged to obtain 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole (fenpiclonil intermediate).

[0045] Comparative Example 3: On the basis of Example 1, the biochar precursor powder prepared in step S1 was used to replace the metal oxide biochar powder in step S4, and the remaining steps remained unchanged to obtain 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole (fenpiclonil intermediate).

[0046] According to the synthesis processes of Examples 1-3 and Comparative Examples 1-3, 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole (fenpiclonil intermediate) was prepared, and the content and yield of the final product were calculated.

[0047] Content (wt%): The test instrument was Agilent HPLC 1200, and the calculation method was as shown in the following formula: W1 = r2×m1×P / (r1×m2), where r1 was the average value of the peak area of 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole in the standard sample solution, r2 was the average value of the peak area of 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole in the sample solution (the product prepared in the experiment), m1 was the mass (g) of the 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole standard sample, m2 was the mass (g) of the sample, and P was the purity of the standard sample, and the value was expressed in %. Yield (%): The calculation method was Yield (%) = actual yield (g) × content (wt%) ÷ theoretical yield (g) × 100%; the calculation results are shown in the following table: Table 1 List of content and yield of the final product

[0048] As can be seen from Table 1, the contents and yields in Examples 1-3 are greater than those in Comparative Examples 1-3. In Comparative Example 1, the composite catalyst powder in Step S7 was removed, and the content and yield of the final product were the lowest. In Comparative Example 2, the metal oxide biochar powder prepared in Step S3 was used to replace the composite catalyst powder in Step S7, and the content and yield of the final product were slightly lower than those in Examples 1-3. In Comparative Example 3, the biochar precursor powder prepared in Step S1 was used to replace the metal oxide biochar powder in Step S4, and the yield of its final product was between those of Comparative Examples 1-2. This shows that nano-aluminum oxide and nano-cerium oxide can jointly absorb hydrogen fluoride gas, and at the same time, nano-palladium particles can promote the substitution of fluoride ions for chloride ions. The synergy of the two can improve the yield and content of 4-(dichloromethyl)-2,2-difluorobenzo[1,3]dioxole (the intermediate of fludioxonil), playing a role in efficient synthesis.

[0049] It should be noted that in this article, terms such as "including", "comprising" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or device.

[0050] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention.

Claims

1. An efficient synthesis process of a fludioxonil intermediate, characterized in that, It includes the following steps: Step 1: Deposit aluminum hydroxide and cerium hydroxide on the biochar precursor powder through aluminum chloride solution and cerium chloride solution to obtain the supported biochar powder; Step 2: Dehydrate the supported biochar powder to obtain the metal oxide biochar powder, then modify it with a silane coupling agent to obtain the modified biochar powder. Generate Pd-MOF through a coordination bond between palladium ions and organic ligands, and graft the modified biochar powder and Pd-MOF together to obtain the composite biochar powder; Step 3: Calcinate the composite biochar powder at high temperature to obtain the composite catalyst powder. Add 4-dichloromethyl-2,2-dichlorobenzene[1,3]dioxolene, potassium fluoride, potassium bifluoride, the composite catalyst powder and anhydrous sulfolane into the reaction kettle, and react for 8-9 h under the conditions of nitrogen and 90-100 °C to obtain 4-dichloromethyl-2,2-difluorobenzene[1,3]dioxolene.

2. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 1, characterized in that, The supported biochar powder described in Step 1 is prepared through the following steps: Place the sludge powder in a muffle furnace for calcination, then add potassium acetate powder to create pores to obtain the biochar precursor powder; then add the aluminum chloride solution with a concentration of 0.1 mol / L, the cerium chloride solution with a concentration of 0.05 mol / L and the biochar precursor powder into the reaction kettle, adjust the pH value to 5-6 with sodium hydroxide, stir for 4-6 h, then adjust the pH value to 7-8 with sodium hydroxide, stir for 4-6 h, filter, wash, and dry to obtain the supported biochar powder.

3. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 2, characterized in that, The dosage ratio of the sludge powder and potassium acetate powder is 50-55 g: 70-80 g; The dosage ratio of the aluminum chloride solution, cerium chloride solution and biochar precursor powder is 200-300 mL: 200-300 mL: 10-15 g.

4. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 1, characterized in that, The metal oxide biochar powder described in Step 2 is prepared through the following steps: Place the supported biochar powder in a tubular furnace, heat it to 300-320 °C at a rate of 5 °C / min in an air atmosphere, keep it warm and react for 2-3 h, heat it to 500-520 °C in a nitrogen atmosphere, keep it warm for 0.5-1 h, and cool it to room temperature to obtain the metal oxide biochar powder.

5. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 1, characterized in that, The modified biochar powder described in Step 2 is prepared through the following steps: Add KH-550, deionized water and dichloromethane into the reaction kettle, react for 2-3 h, then add the metal oxide biochar powder, ethanol and ammonia water, and react for 5-6 h under the conditions of 70-80 °C and 500-800 r / min, filter, wash, and dry to obtain the modified biochar powder.

6. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 5, characterized in that, The dosage ratio of KH-550, deionized water, dichloromethane, metal oxide biochar powder, ethanol and ammonia water is: 3-5 mL: 50-60 mL: 90-100 mL: 10-15 g: 150-200 mL: 25-30 mL.

7. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 1, characterized in that, The composite biochar powder described in Step 2 is prepared through the following steps: Add palladium chloride solution, 4,4'-bipyridine and ethylene glycol solution into a reaction kettle, react at 100 - 120 °C and 300 - 500 r / min for 24 - 48 h, then add modified biochar powder and N,N-dimethylformamide, react at 80 - 90 °C and 500 - 800 r / min for 8 - 9 h, filter, wash and dry to obtain composite biochar powder.

8. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 7, characterized in that, The dosage ratio of the palladium chloride solution, 4,4'-bipyridine, ethylene glycol solution, modified biochar powder and N,N-dimethylformamide is: 20 - 30 mL : 15 - 20 g : 600 - 700 mL : 10 - 15 g : 300 - 400 mL.

9. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 1, characterized in that, The composite catalyst powder in step three is prepared by the following steps: Place the composite biochar powder in a tubular furnace, heat it to 350 - 400 °C at a rate of 5 °C / min under a mixed atmosphere of argon and hydrogen, hold for reaction for 2 - 3 h, and cool to room temperature to obtain composite catalyst powder.

10. The high-efficiency synthesis process of a fludioxonil intermediate according to claim 1, characterized in that, The dosage ratio of 4-dichloromethyl-2,2-dichlorobenzo[1,3]dioxole, potassium fluoride, potassium bifluoride, composite catalyst powder and anhydrous sulfolane is: 30 - 32 g : 16 - 18 g : 2 - 3 g : 0.1 - 0.5 g : 50 - 100 mL.

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