An efficient synthesis process for fludioxonil intermediate

Abstract

The invention discloses an efficient synthesis process for a fludioxonil intermediate, belonging to the technical field of organic synthesis. Nano-alumina and nano-cerium oxide are filled in the pores of supported biochar powder, the metal oxide biochar powder is modified by a silane coupling agent, and Pd-MOF is grafted onto the modified biochar powder. The three-dimensional spatial structure of the MOF is utilized to provide more active sites for palladium, thereby improving the catalytic efficiency of palladium, promoting the replacement of chloride ions by fluoride ions, and facilitating the efficient progress of the reaction. The porous structure in the composite biochar powder can increase the loading rate of the nano-alumina and nano-cerium oxide, while the Lewis acid sites on the surfaces of the nano-alumina and nano-cerium oxide can adsorb hydrogen fluoride molecules. The hydrogen fluoride molecules are enriched in the composite catalyst powder by physical adsorption and chemical bonding, and then react with excess potassium fluoride to generate potassium bifluoride, thereby suppressing the thermal decomposition reaction rate of the potassium bifluoride.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a high-efficiency synthesis process of a fludioxonil intermediate. Background Art

[0002] Fludioxonil is a broad-spectrum, highly effective, non-systemic phenylpyrrole fungicide that inhibits histidine kinase activity in fungal signal transduction pathways. It is widely used in crop disease control and postharvest preservation of fruits and vegetables. Its core structure is 3-(2,2-difluoro-1,3-benzodioxolan-4-yl)-1H-pyrrole-2-carbonitrile. The synthesis efficiency of the key intermediate, 2,2-difluorobenzodioxolan-4-amine (DFBD), directly determines the cost and industrial feasibility of the final product. Traditionally, DFBD is synthesized using catechol as the starting material through a multi-step process involving epoxidation, fluorination, nitration, and reduction.

[0003] A Chinese invention patent application with publication number CN101851225B discloses a method for synthesizing 4-formyl-2,2-difluorobenzodioxole, an intermediate of fludioxonil. The method uses cheap and readily available o-cresol as a starting material, obtains 3-methyl salicylaldehyde through ortho-directed formylation, converts 3-methyl salicylaldehyde into 3-methylcatechol through the Dakin reaction, and then directly reacts with dichloromethane or dibromomethane without separation or purification to produce 4-methylbenzodioxole. The product then undergoes a three-step reaction of chlorination, fluorination, and oxidation to produce 4-formyl-2,2-difluorobenzodioxole. This method significantly reduces production costs, avoids the use of chlorine, and reduces the risk of environmental pollution.

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

[0005] The present invention aims to provide an efficient synthesis process for a fludioxonil intermediate. The process comprises the following steps: loading aluminum hydroxide and cerium hydroxide on a biochar precursor powder, dehydrating the biochar precursor powder at high temperature to form aluminum oxide and cerium oxide; grafting the biochar precursor powder with Pd-MOF; reducing the palladium ions to nano-palladium through reduction; utilizing the MOF spatial structure to uniformly load the nano-palladium on the composite biochar powder to obtain a composite catalyst powder; and then conducting a synthesis reaction. The process solves the problem that potassium bifluoride is easily decomposed at high temperature to release hydrogen fluoride, thereby achieving the effects of reducing hydrogen fluoride gas emissions and improving the utilization rate of fluorine atoms.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] An efficient synthesis process for a fludioxonil intermediate comprises the following steps:

[0008] Step 1: Aluminum hydroxide and cerium hydroxide are deposited on biochar precursor powder using aluminum chloride solution and cerium chloride solution to obtain supported biochar powder.

[0009] Step 2: Dehydrate the loaded biochar powder to obtain metal oxide biochar powder, then modify it with a silane coupling agent to obtain modified biochar powder, generate Pd-MOF through coordination bonds between palladium ions and organic ligands, and graft the modified biochar powder and Pd-MOF together to obtain composite biochar powder.

[0010] Step 3: calcining the composite biochar powder at high temperature to obtain a composite catalyst powder, adding 4-dichloromethyl-2,2-dichlorobenzo[1,3]dioxole, potassium fluoride, potassium bifluoride, composite catalyst powder and anhydrous sulfolane into a reactor, reacting under nitrogen and 90-100°C for 8-9 hours to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole.

[0011] Furthermore, the supported biochar powder is prepared by the following steps:

[0012] The sludge powder was placed in a muffle furnace and calcined, and potassium acetate powder was added to form pores to obtain biochar precursor powder. A 0.1 mol / L aluminum chloride solution, a 0.05 mol / L cerium chloride solution and the biochar precursor powder were then added to the reactor. The pH value was adjusted to 5-6 with sodium hydroxide and stirred for 4-6 hours. The pH value was then adjusted to 7-8 with sodium hydroxide and stirred for 4-6 hours. The mixture was filtered, washed and dried to obtain loaded biochar powder.

[0013] Furthermore, the usage ratio of sludge powder to potassium acetate powder is 50-55g:70-80g.

[0014] Furthermore, the usage ratio of aluminum chloride solution, cerium chloride solution and biochar precursor powder is 200-300 mL: 200-300 mL: 10-15 g.

[0015] Furthermore, metal oxide biochar powder is prepared by the following steps:

[0016] The loaded biochar powder was placed in a tube furnace, heated to 300-320°C at a rate of 5°C / min in an air atmosphere, kept warm for 2-3 hours, heated to 500-520°C in a nitrogen atmosphere, kept warm for 0.5-1 hour, and cooled to room temperature to obtain metal oxide biochar powder.

[0017] Furthermore, the modified biochar powder is prepared by the following steps:

[0018] KH-550, deionized water and dichloromethane were added to a reactor and reacted for 2-3 hours. Metal oxide biochar powder, ethanol and ammonia water were then added and reacted at 70-80°C and 500-800 r / min for 5-6 hours. The reaction was then filtered, washed and dried to obtain modified biochar powder.

[0019] Furthermore, the usage 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.

[0020] Furthermore, the composite biochar powder is prepared by the following steps:

[0021] Add palladium chloride solution, 4,4'-bipyridine and ethylene glycol solution into a reactor, react at 100-120°C and 300-500 r / min for 24-48 hours, then add modified biochar powder and N,N-dimethylformamide, react at 80-90°C and 500-800 r / min for 8-9 hours, filter, wash and dry to obtain composite biochar powder.

[0022] Furthermore, the usage 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.

[0023] Furthermore, the composite catalyst powder is prepared by the following steps:

[0024] The composite biochar powder was placed in a tube furnace, heated to 350-400° C. at a rate of 5° C. / min in a mixed atmosphere of argon and hydrogen, kept warm for 2-3 hours, and cooled to room temperature to obtain a composite catalyst powder.

[0025] Furthermore, the usage 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.

[0026] Beneficial effects of the present invention:

[0027] The composite catalyst powder of the present invention is prepared by filling the pores of the supported biochar powder with nano-alumina and nano-cerium oxide, then modifying the metal oxide biochar powder with a silane coupling agent, and grafting Pd-MOF onto the modified biochar powder to obtain a composite biochar powder, which is then placed in a mixed atmosphere of hydrogen and argon and calcined at high temperature. During the calcination process, palladium ions are reduced to nano-palladium, and the three-dimensional spatial structure of MOF provides more active sites for palladium, which can improve the catalytic efficiency of palladium, promote the replacement of chloride ions with fluoride ions, and facilitate the reaction. The process is carried out efficiently. The porous structure in the composite biochar powder can increase the loading rate of nano-alumina and nano-cerium oxide, and the Lewis acid sites on the surface of nano-alumina and nano-cerium oxide 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 the hydrogen fluoride molecules in the composite catalyst powder through physical adsorption and chemical combination, and then generate potassium bifluoride with excess potassium fluoride, inhibiting the thermal decomposition reaction rate of potassium bifluoride, thereby improving the utilization rate of fluorine atoms in the reactants and improving the synthesis efficiency of the fludioxonil intermediate.

[0028] In the present invention, the metal oxide biochar powder is prepared by first calcining sludge powder, then mixing it with potassium acetate powder and performing secondary calcination. The activation process of potassium acetate is utilized to promote the partial ablation of silicon dioxide and calcium carbonate crystals in the sludge powder. At the same time, the potassium acetate decomposes to generate carbon dioxide gas, which can produce a pore-forming effect, thereby obtaining a biochar precursor powder with a larger specific surface area. Aluminum chloride solution and cerium chloride solution are then reacted under alkaline conditions to generate aluminum hydroxide and cerium hydroxide, which are deposited on the biochar precursor powder. The mixture is then placed in a tubular furnace under an air atmosphere and heated for dehydration, so that nano-aluminum oxide and nano-cerium oxide can be evenly distributed in the pores of the loaded biochar powder. The increased specific surface area can increase the loading rate of the nano-metal oxide and also increase the contact area with hydrogen fluoride. DETAILED DESCRIPTION

[0029] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] Example 1: This example provides an efficient synthesis process for a fludioxonil intermediate, comprising the following steps:

[0031] S1: Wrap 52.5 g of dried sludge powder with tin foil, put it into a muffle furnace and heat it to 625 ° C at a rate of 10 ° C / min, keep it warm for 1 hour, cool it to room temperature, add 75 g of potassium acetate powder, mix it evenly, put it into a muffle furnace and heat it to 625 ° C at a rate of 10 ° C / min, keep it warm for 1 hour. The potassium acetate activation process promotes the partial melting of silica and calcium carbonate crystals in the sludge powder. At the same time, potassium acetate undergoes a gasification reaction, produces a pore-forming effect, and increases the specific surface area. Wash it four times with a hydrochloric acid solution with a concentration of 0.1 mol / L, and dry it at 85 ° C for 8 hours to obtain a biochar precursor powder.

[0032] S2: Add 250 mL of 0.1 mol / L aluminum chloride solution and 250 mL of 0.05 mol / L cerium chloride solution into the reactor and mix well. Then add 12.5 g of biochar precursor powder. First, adjust the pH value to 5 with sodium hydroxide solution, stir at 22 ° C and 400 r / min for 5 hours to deposit aluminum hydroxide on the biochar precursor powder. Then adjust the pH value to 7 with sodium hydroxide solution, stir for 5 hours, and deposit cerium hydroxide on the biochar precursor powder. Centrifuge and filter, wash the filter cake with deionized water 4 times, and dry at 85 ° C for 8 hours to obtain loaded biochar powder.

[0033] S3: Place the loaded biochar powder in a tubular furnace, heat it to 310°C at a rate of 5°C / min in an air atmosphere, keep it warm for 2 hours, heat it to 510°C in a nitrogen atmosphere, keep it warm for 0.5 hours, dehydrate aluminum hydroxide and cerium hydroxide to form nano-aluminum oxide and nano-cerium oxide and fill the pores of the loaded biochar powder, reducing the contact area between biochar and oxygen, and cool it to room temperature to obtain metal oxide biochar powder.

[0034] S4: Add 4 mL of silane coupling agent KH-550, 55 mL of deionized water and 95 mL of dichloromethane into the reactor, react at 22 ° C and 400 r / min for 2 hours, then add 12.5 g of 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 hours to graft KH-550 onto the metal oxide biochar powder to form Si-OC bonds. Cool to room temperature, filter, and wash the filter cake alternately with anhydrous ethanol and deionized water 4 times, and dry at 70 ° C for 10 hours to obtain modified biochar powder.

[0035] S5: Add 25 mL of palladium chloride solution, 17.5 g of 4,4'-bipyridine and 650 mL of ethylene glycol solution into the reactor and react at 110 ° C and 400 r / min for 36 hours. A coordination bond is formed between the palladium ions and the ligand 4,4'-bipyridine to generate Pd-MOF. Cool to room temperature, then add 12.5 g of modified biochar powder and 350 mL of N, N-dimethylformamide, and react at 85 ° C and 650 r / min for 8 hours. The amino group on the silane coupling agent KH-550 forms a coordination bond with the metal ion of Pd-MOF. Cool to room temperature, centrifuge and filter. The filter cake is washed 4 times with ethylene glycol and deionized water respectively, and freeze-dried to obtain composite biochar powder.

[0036] S6: 12.5 g of composite biochar powder was placed in a tubular furnace, and the temperature was raised to 375 ° C at a rate of 5 ° C / min in a mixed atmosphere of argon and hydrogen. The reaction was kept at this temperature for 2 hours. The nano palladium particles were evenly distributed in the pores of the composite biochar. The mixture was cooled to room temperature to obtain a composite catalyst powder.

[0037] S7: 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 were added to a reactor. The temperature was raised to 95°C under nitrogen protection and the reaction was carried out 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, which allows hydrofluoric acid to be enriched inside the composite catalyst powder. This then promotes the reaction between hydrofluoric acid and excess potassium fluoride to form potassium bifluoride, thereby improving the utilization rate of fluorine atoms. The mixture was cooled to room temperature, filtered, and the filtrate was concentrated under reduced pressure. The mixture was then extracted with ethyl acetate four times. The ethyl acetate was evaporated at 77°C to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (a fludioxonil intermediate).

[0038] Example 2: This example provides an efficient synthesis process for a fludioxonil intermediate, comprising the following steps:

[0039] S1: Wrap 50g of dried sludge powder with tin foil, put it into a muffle furnace and heat it to 600℃ at a rate of 10℃ / min, keep it warm for 1h, cool it to room temperature, add 70g of potassium acetate powder, mix it evenly, put it into a muffle furnace and heat it to 600℃ at a rate of 10℃ / min, keep it warm for 1h. The potassium acetate activation process promotes the partial melting of silica and calcium carbonate crystals in the sludge powder. At the same time, potassium acetate undergoes a gasification reaction, produces a pore-forming effect, and increases the specific surface area. Wash it three times with a hydrochloric acid solution with a concentration of 0.1mol / L, and dry it at 80℃ for 8h to obtain biochar precursor powder.

[0040] S2: Add 200 mL of 0.1 mol / L aluminum chloride solution and 200 mL of 0.05 mol / L cerium chloride solution into the reactor and mix well. 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 hours to deposit aluminum hydroxide on the biochar precursor powder. Then adjust the pH value to 7 with sodium hydroxide solution, stir for 4 hours, and deposit cerium hydroxide on the biochar precursor powder. Centrifuge and filter. Wash the filter cake 3 times with deionized water and dry at 80°C for 8 hours to obtain loaded biochar powder.

[0041] S3: Place the loaded biochar powder in a tubular furnace, heat it to 300°C at a rate of 5°C / min in an air atmosphere, keep it warm for 2 hours, heat it to 500°C in a nitrogen atmosphere, keep it warm for 0.5 hours, aluminum hydroxide and cerium hydroxide are dehydrated to form nano-aluminum oxide and nano-cerium oxide and fill the pores of the loaded biochar powder, reducing the contact area between biochar and oxygen, and cool it to room temperature to obtain metal oxide biochar powder.

[0042] S4: Add 3 mL of silane coupling agent KH-550, 50 mL of deionized water and 90 mL of dichloromethane into the reactor, 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, and react at 70°C and 500 r / min for 5 h to graft KH-550 onto the metal oxide biochar powder to form Si-OC bonds. Cool to room temperature, filter, and wash the filter cake alternately with anhydrous ethanol and deionized water three times, and dry at 60°C for 8 h to obtain modified biochar powder.

[0043] S5: Add 20 mL of palladium chloride solution, 15 g of 4,4'-bipyridine and 600 mL of ethylene glycol solution into the reactor and react at 100 ° C and 300 r / min for 24 hours. A coordination bond is formed between the palladium ions and the ligand 4,4'-bipyridine to generate Pd-MOF. Cool to room temperature, add 10 g of modified biochar powder and 300 mL of N, N-dimethylformamide, and react at 80 ° C and 500 r / min for 8 hours. The amino group on the silane coupling agent KH-550 forms a coordination bond with the metal ion of Pd-MOF. Cool to room temperature, centrifuge and filter. The filter cake is washed three times with ethylene glycol and deionized water respectively, and freeze-dried to obtain composite biochar powder.

[0044] S6: Place 10 g of 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, and keep it warm for 2 hours. The nanopalladium particles are evenly distributed in the pores of the composite biochar. Cool it to room temperature to obtain a composite catalyst powder.

[0045] S7: 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 were added to a reactor. The temperature was raised to 90°C under nitrogen protection and the reaction was carried out for 8 h. The Lewis acid sites on the surfaces of alumina and cerium oxide can adsorb hydrofluoric acid molecules, and the porous structure of biochar provides more active sites, which allows hydrofluoric acid to be enriched inside the composite catalyst powder. Then, the reaction between hydrofluoric acid and excess potassium fluoride is promoted to generate potassium bifluoride, thereby improving the utilization rate of fluorine atoms. The mixture was cooled to room temperature, filtered, and the filtrate was concentrated under reduced pressure. The mixture was extracted with ethyl acetate three times, and the ethyl acetate was evaporated at 75°C to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (fludioxonil intermediate).

[0046] Example 3: This example provides an efficient synthesis process for a fludioxonil intermediate, comprising the following steps:

[0047] S1: Wrap 55g of dried sludge powder with tin foil, put it into a muffle furnace and heat it to 650℃ at a rate of 10℃ / min, keep it warm for 1.5h, cool it to room temperature, add 80g of potassium acetate powder, mix it evenly, put it into a muffle furnace and heat it to 650℃ at a rate of 10℃ / min, keep it warm for 1.5h. The potassium acetate activation process promotes the partial melting of silica and calcium carbonate crystals in the sludge powder. At the same time, potassium acetate undergoes a gasification reaction, produces a pore-forming effect, and increases the specific surface area. Wash it with a hydrochloric acid solution with a concentration of 0.1mol / L 5 times, and dry it at 90℃ for 9h to obtain biochar precursor powder.

[0048] S2: Add 300 mL of 0.1 mol / L aluminum chloride solution and 300 mL of 0.05 mol / L cerium chloride solution into the reactor and mix well. 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 hours to deposit aluminum hydroxide on the biochar precursor powder. Then adjust the pH value to 8 with sodium hydroxide solution, stir for 6 hours, and deposit cerium hydroxide on the biochar precursor powder. Centrifuge and filter. Wash the filter cake with deionized water 5 times and dry at 90°C for 9 hours to obtain loaded biochar powder.

[0049] S3: Place the loaded biochar powder in a tubular furnace, heat it to 320°C at a rate of 5°C / min in an air atmosphere, keep it warm for 3 hours, heat it to 520°C in a nitrogen atmosphere, keep it warm for 1 hour, aluminum hydroxide and cerium hydroxide are dehydrated to form nano-aluminum oxide and nano-cerium oxide and fill the pores of the loaded biochar powder, reducing the contact area between biochar and oxygen, and cool it to room temperature to obtain metal oxide biochar powder.

[0050] S4: Add 5 mL of silane coupling agent KH-550, 60 mL of deionized water and 100 mL of dichloromethane into the reactor, react at 25 ° C and 500 r / min for 3 hours, then add 15 g of metal oxide biochar powder, 200 mL of ethanol and 30 mL of ammonia water, and react at 80 ° C and 800 r / min for 6 hours to graft KH-550 onto the metal oxide biochar powder to form Si-OC bonds. Cool to room temperature, filter, and wash the filter cake alternately with anhydrous ethanol and deionized water 5 times, and dry at 80 ° C for 12 hours to obtain modified biochar powder.

[0051] S5: Add 30 mL of palladium chloride solution, 20 g of 4,4'-bipyridine and 700 mL of ethylene glycol solution into the reactor and react at 120 ° C and 500 r / min for 48 hours. A coordination bond is formed between the palladium ions and the ligand 4,4'-bipyridine to generate Pd-MOF. Cool to room temperature, add 15 g of modified biochar powder and 400 mL of N, N-dimethylformamide, and react at 90 ° C and 800 r / min for 9 hours. The amino group on the silane coupling agent KH-550 forms a coordination bond with the metal ion of Pd-MOF. Cool to room temperature, centrifuge and filter. The filter cake is washed with ethylene glycol and deionized water 5 times respectively, and freeze-dried to obtain composite biochar powder.

[0052] S6: Place 15 g of composite biochar powder in a tubular furnace, heat it to 400 °C at a rate of 5 °C / min in a mixed atmosphere of argon and hydrogen, and keep it warm for 3 hours. The nanopalladium particles are evenly distributed in the pores of the composite biochar. Cool it to room temperature to obtain a composite catalyst powder.

[0053] S7: 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 composite catalyst powder and 100 mL of anhydrous sulfolane were added to a reactor. The temperature was raised to 100°C under nitrogen protection and the reaction was carried out for 9 hours. The Lewis acid sites on the surfaces of alumina and cerium oxide can adsorb hydrofluoric acid molecules, and the porous structure of biochar provides more active sites, which allows hydrofluoric acid to be enriched inside the composite catalyst powder. Then, the reaction between hydrofluoric acid and excess potassium fluoride is promoted to generate potassium bifluoride, thereby improving the utilization rate of fluorine atoms. The reaction was cooled to room temperature, filtered, and the filtrate was concentrated under reduced pressure. Then, the filtrate was extracted with ethyl acetate five times. The ethyl acetate was evaporated at 80°C to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (fludioxonil intermediate).

[0054] Comparative Example 1: Based on 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 (fludioxonil intermediate).

[0055] Comparative Example 2: Based on Example 1, the metal oxide biochar powder prepared in step S3 was used to replace the composite catalyst powder in step S7, and the other steps remained unchanged to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (fludioxonil intermediate).

[0056] Comparative Example 3: Based on Example 1, the metal oxide biochar powder in step S4 was replaced by the biochar precursor powder prepared in step S1, and the other steps remained unchanged to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (fludioxonil intermediate).

[0057] According to the synthesis process of Example 1-3 and Comparative Example 1-3, 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (fludioxonil intermediate) was prepared, and the content and yield of the final product were calculated.

[0058] Content (wt%): The test instrument is Agilent HPLC 1200, and the calculation method is as follows: W1=r2×m1×P / (r1×m2), where r1 is the average peak area of ​​4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole in the standard solution, r2 is the average peak area of ​​4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole in the sample solution (experimentally prepared product), m1 is the mass of 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole standard (g), m2 is the mass of the sample (g), and P is the purity of the standard. The value is expressed in %.

[0059] Yield (%): Calculation method is yield (%) = actual yield (g) × content (weight %) ÷ theoretical yield (g) × 100%; the calculation results are shown in the following table:

[0060] Table 1 Content and yield of final product

[0061]

[0062] As can be seen from Table 1, the content and yield in Examples 1-3 are greater than the content and yield in Comparative Examples 1-3. Comparative Example 1 removes the composite catalyst powder in step S7, and the content and yield of its final product are the lowest. Comparative Example 2 replaces the composite catalyst powder in step S7 with the metal oxide biochar powder prepared in step S3, and the final product, content and yield are slightly lower than those in Examples 1-3. Comparative Example 3 replaces the metal oxide biochar powder in step S4 with the biochar precursor powder prepared in step S1, and its final product and yield are between Comparative Examples 1-2, indicating that nano-alumina and nano-cerium oxide can jointly absorb hydrogen fluoride gas, and nano-palladium particles can promote the replacement of chloride ions with fluoride ions. The two can synergistically increase the yield and content of 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole (fludioxonil intermediate), thereby achieving efficient synthesis.

[0063] It should be noted that, in this document, terms such as "comprises", "includes" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus that includes a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements that are inherent to such process, method, article or apparatus.

[0064] While the embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that various changes, modifications, substitutions, and alterations can be made to the embodiments without departing from the principles and spirit of the invention.

Claims

1. An efficient synthesis process for a fludioxonil intermediate, characterized in that: The steps include: Step 1: depositing aluminum hydroxide and cerium hydroxide on biochar precursor powder using aluminum chloride solution and cerium chloride solution to obtain supported biochar powder; Step 2: Dehydrating the loaded biochar powder to obtain metal oxide biochar powder, then modifying it with a silane coupling agent to obtain a modified biochar powder, generating Pd-MOF through coordination bonds between palladium ions and organic ligands, and grafting the modified biochar powder and Pd-MOF together to obtain a composite biochar powder; Step 3: calcining the composite biochar powder at 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 reactor, reacting under nitrogen at 90-100° C. for 8-9 hours to obtain 4-dichloromethyl-2,2-difluorobenzo[1,3]dioxole; The composite biochar powder is prepared by the following steps: Add palladium chloride solution, 4,4'-bipyridine and ethylene glycol solution into a reactor, react at 100-120°C and 300-500 r / min for 24-48 hours, then add modified biochar powder and N,N-dimethylformamide, react at 80-90°C and 500-800 r / min for 8-9 hours, filter, wash and dry to obtain composite biochar powder; The composite catalyst powder in step 3 is prepared by the following steps: The composite biochar powder was placed in a tube furnace, heated to 350-400° C. at a rate of 5° C. / min in a mixed atmosphere of argon and hydrogen, kept warm for 2-3 hours, and cooled to room temperature to obtain a composite catalyst powder.

2. The efficient synthesis process of a fludioxonil intermediate according to claim 1, wherein The supported biochar powder in step 1 is prepared by the following steps: The sludge powder was placed in a muffle furnace and calcined, and potassium acetate powder was added to form pores to obtain biochar precursor powder. A 0.1 mol / L aluminum chloride solution, a 0.05 mol / L cerium chloride solution and the biochar precursor powder were then added to the reactor. The pH value was adjusted to 5-6 with sodium hydroxide and stirred for 4-6 hours. The pH value was then adjusted to 7-8 with sodium hydroxide and stirred for 4-6 hours. The mixture was filtered, washed and dried to obtain loaded biochar powder.

3. A highly efficient synthesis process for a fludioxonil intermediate according to claim 2, characterized in that: The sludge powder and potassium acetate powder are used in a ratio of 50-55g:70-80g; The usage 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.

4. The efficient synthesis process of a fludioxonil intermediate according to claim 1, wherein The metal oxide biochar powder in step 2 is prepared by the following steps: The loaded biochar powder was placed in a tube furnace, heated to 300-320°C at a rate of 5°C / min in an air atmosphere, kept warm for 2-3 hours, heated to 500-520°C in a nitrogen atmosphere, kept warm for 0.5-1 hour, and cooled to room temperature to obtain metal oxide biochar powder.

5. The efficient synthesis process of a fludioxonil intermediate according to claim 1, wherein The modified biochar powder in step 2 is prepared by the following steps: KH-550, deionized water and dichloromethane were added to a reactor and reacted for 2-3 hours. Metal oxide biochar powder, ethanol and ammonia water were then added and reacted at 70-80°C and 500-800 r / min for 5-6 hours. The reaction was then filtered, washed and dried to obtain modified biochar powder.

6. The efficient synthesis process of a fludioxonil intermediate according to claim 5, characterized in that: The dosage ratio of the 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 efficient synthesis process of a fludioxonil intermediate according to claim 1, wherein: The usage 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.

8. The efficient synthesis process of a fludioxonil intermediate according to claim 1, wherein: The usage ratio of the 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.

Images