Synthesis method of 1, 1, 3, 3-tetrafluoro-2-acetone

Abstract

The invention provides a synthesis method of 1, 1, 3, 3-tetrafluoro-2-acetone, and belongs to the technical field of fluorine-containing compound synthesis. The method comprises the following steps: by taking ethyl 4, 4-difluoroacetoacetate as a raw material, carrying out fluorination reaction to obtain an intermediate difluoroacetyl ethyl difluoroacetate; the intermediate is subjected to a hydrolysis decarboxylation reaction to generate 1, 1, 3, 3-tetrafluoro-2-acetone, and then the product is extracted and purified through normal-pressure rectification separation to obtain the 1, 1, 3, 3-tetrafluoro-2-acetone. The method is mild in reaction condition, short in reaction time and high in treatment efficiency, the purity of the prepared 1, 1, 3, 3-tetrafluoro-2-acetone reaches 97.8% or above, and the highest purity can reach 98.5%; the yield reaches 77.4% or above; meanwhile, the method is easy to operate, low in cost, environmentally friendly, safe, reliable and low in equipment requirement.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of fluorine-containing compound synthesis, and relates to a synthesis method of 1,1,3,3-tetrafluoro-2-propanone. BACKGROUND

[0002] 1,1,3,3-tetrafluoro-2-propanone, abbreviated as tetrafluoropropanone, has a CAS number of 360-52-1, and is characterized by two difluoromethyl groups on both sides of a carbonyl group. 1,1,3,3-tetrafluoro-2-propanone is an important fluorine-containing ketone compound and an important intermediate for synthesizing organic fluorine compounds, and thus can be applied to the fields of medicine, pesticide, and new material synthesis.

[0003] For fluorine-containing ketone compounds, hexafluoropropanone is the most widely used, and many synthesis methods thereof are known. For example, patents with publication numbers of US3321515, US4238416, JP58062131, and CN1899692A disclose a method for preparing hexafluoropropanone by isomerization from hexafluoropropane oxide, and these methods mostly use Lewis acid or modified Lewis acid compounds as catalysts to improve the conversion rate of hexafluoropropane oxide and the selectivity of hexafluoropropanone.

[0004] However, no relevant patent reports have been found about the synthesis method of tetrafluoropropanone. Therefore, it is necessary to develop a safe, green, and environmentally friendly, and simple operation method for synthesizing tetrafluoropropanone. SUMMARY

[0005] In order to achieve the above-mentioned purpose, the application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone.

[0006] To achieve the above-mentioned purpose, the application adopts the following technical solutions: The application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S01: mixing 4,4-difluoroacetyl acetate, a fluorination reagent, and a solvent, and then performing fluorination reaction to obtain difluoroacetyl difluoroacetic acid ethyl ester; S02: performing hydrolysis and decarboxylation on the difluoroacetyl difluoroacetic acid ethyl ester to obtain a reaction liquid; S03: performing extraction, drying, and normal pressure rectification on the reaction liquid to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0007] In the application, the fluorination reaction temperature is 50-150 DEG C, and the reaction time is 1-6 h; after the fluorination reaction is completed, the temperature is lowered to room temperature, and the solvent is distilled to obtain the difluoroacetyl difluoroacetic acid ethyl ester.

[0008] In the present application, the hydrolysis and decarboxylation of ethyl difluoroacetyl difluoroacetate to obtain a reaction solution comprises: adding ethyl difluoroacetyl difluoroacetate dropwise to an alkaline solution, heating the solution to 40-80° C., adjusting the pH value to acidic, and keeping the temperature for reaction for 1-5 hours to obtain a reaction solution.

[0009] In the present application, the reflux ratio of atmospheric distillation is 10:1-1:1, the tower bottom temperature is 66.8-71.8°C, and the tower top temperature is 59.8-63.8°C.

[0010] The present invention has the following beneficial effects: (1) This application uses ethyl 4,4-difluoroacetoacetate as a raw material and obtains an intermediate ethyl difluoroacetate through a fluorination reaction; the intermediate is subjected to a hydrolysis decarboxylation reaction to generate 1,1,3,3-tetrafluoro-2-propanone, and the product is separated and purified by extraction and atmospheric distillation.

[0011] (2) This method has mild reaction conditions, short reaction time, and high processing efficiency. The purity of the prepared 1,1,3,3-tetrafluoro-2-propanone reaches above 97.8%, and can reach up to 98.5%; the yield reaches above 77.4%. At the same time, this method is simple to operate, low in cost, green and environmentally friendly, safe and reliable, and has low equipment requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 This is the NMR spectrum of 1,1,3,3-tetrafluoro-2-propanone prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0013] Explanation of terms: Ethyl 4,4-difluoroacetoacetate: molecular formula is C6H8F2O3, CAS number is 352-24-9, it is a colorless to light yellow liquid.

[0014] Fluorination reagent refers to a reagent containing fluorine element, such as fluorine gas diluted with nitrogen, 1-chloromethyl-4-fluoro-1,4-diazabicyclo[2.2.2]octane di(tetrafluoroborate), 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octane tetrafluoroborate, 1-fluoropyridine tetrafluoroborate, N-fluorobisbenzenesulfonimide, N-fluoropyridine trifluoromethanesulfonate, etc. In this application, any one or more of the above fluorination reagents are selected.

[0015] The solvent is used to dissolve ethyl 4,4-difluoroacetoacetate and the fluorination reagent, and can be selected from one or more of tetrahydrofuran, acetonitrile, toluene, dichloromethane, methanol, trifluorotoluene, water, and hexafluorobenzene.

[0016] The alkali solution is used to provide an alkaline environment for the reaction product of 4,4-difluoroacetylacetate and a fluorinating agent, and can be selected from an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or lithium hydroxide, preferably an aqueous solution of sodium hydroxide or potassium hydroxide.

[0017] The extractant is an organic solvent for extracting 1,1,3,3-tetrafluoro-2-propanone, and can be selected from one or more of ethyl acetate, diethyl ether, propyl ether, dichloromethane, methyl tert-butyl ether, preferably diethyl ether and / or methyl tert-butyl ether.

[0018] The drying agent is used to dry the reaction product, and can be selected from one or more of anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and 5A molecular sieve.

[0019] In the present application, 4,4-difluoroacetylacetate is used as a raw material, and an intermediate is obtained by fluorination reaction of a fluorinating agent. The intermediate is obtained by distillation, adjustment of an alkali solution, acid adjustment, extraction, and normal pressure rectification after drying.

[0020] Specifically, the synthesis method of 1,1,3,3-tetrafluoro-2-propanone provided by the present application comprises: S01: 4,4-difluoroacetylacetate and a fluorinating agent are added to a solvent in a molar ratio of 1:1.8-1:2.6, stirring is started, and the temperature is raised to 50-150°C for 1-6h of incubation. After the reaction is completed, the temperature is lowered to room temperature, and the reaction liquid obtained by the reaction is distilled to remove the solvent to obtain an intermediate, difluoroacetyl difluoroacetic acid.

[0021] More preferably, the molar ratio of 4,4-difluoroacetylacetate to the fluorinating agent is 1:2-1:2.3, and the reaction temperature is 60-120°C. The amount of solvent used in the present application is not limited, as long as it can dissolve 4,4-difluoroacetylacetate and the fluorinating agent and does not affect the reaction.

[0022] S02: An alkali solution is added to the reaction bottle, and stirring is started. Difluoroacetyl difluoroacetic acid is added dropwise to the alkali solution, and after the temperature is raised to 40-80°C, acid is added dropwise to adjust the pH value to 1-6, and incubated for 1-5h to obtain a reaction liquid.

[0023] In the present application, the molar ratio of difluoroacetyl difluoroacetic acid to the alkali solution is 1:1-1:2; the mass concentration of the alkali solution is 1-30%; and the acid is selected from one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, and hydroiodic acid. More preferably, the molar ratio of difluoroacetyl difluoroacetic acid to the alkali solution is 1:1-1:1.5; the mass concentration of the alkali solution is 4-15%; the acid is selected from hydrochloric acid, sulfuric acid, or nitric acid; and the pH value is adjusted to 2-4 using the acid.

[0024] S03: After the reaction solution is cooled to room temperature, the reaction solution is extracted with an extractant, and the organic phase obtained by extraction is dried with a drying agent, and then subjected to normal pressure rectification at a bottom temperature of 66.8-71.8℃, a top temperature of 59.8-63.8℃, and a reflux ratio of 10:1-1:1 to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0025] In the present application, the dried organic phase can be filtered and then rectified, or can be directly rectified without filtration. In order to save synthesis time, the drying agent in the organic phase is not filtered in the present application, but is directly subjected to normal pressure rectification.

[0026] The technical solutions of the present application are further explained and described below through specific examples.

[0027] Example 1 The present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises: S101: 83.1g of ethyl 4,4-difluoroacetoacetate, 371.9g of 1-chloromethyl-4-fluoro-1,4-diazabicyclo[2.2.2]octane di(tetrafluoroborate) salt and 170mL of acetonitrile are added to a reaction bottle, stirring is started, and the temperature is raised to 80℃ for 4h. After the reaction is completed, the temperature is lowered to room temperature, and the reaction solution obtained by the reaction is distilled to evaporate acetonitrile, and 96.0g of intermediate difluoroacetyl difluoroacetic acid is obtained.

[0028] S102: 366g of 8% potassium hydroxide solution is added to the reaction bottle, and stirring is started. The ethyl difluoroacetyl difluoroacetate is added dropwise to the potassium hydroxide solution, and after the temperature is raised to 50℃, nitric acid is added dropwise to adjust the pH value to 3, and the reaction is maintained for 3h to obtain a reaction solution.

[0029] S103: After the reaction solution is cooled to room temperature, 449.3g of the reaction solution is transferred to a separatory funnel, and 400mL of diethyl ether is added for extraction. After the extraction is completed, the layers are separated, the organic phase is collected, and phosphorus pentoxide is added to the organic phase for drying. The dried organic phase is transferred to a batch rectification column, and subjected to rectification under normal pressure, a reflux ratio of 5:1, a bottom temperature of 70℃, and a top temperature of 60℃ to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0030] Example 2 The present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises: S201: 83.1 g of ethyl 4,4-difluoroacetoacetate and 100 mL of methanol were added to a reaction bottle, nitrogen-diluted fluorine gas was introduced, the amount of fluorine gas introduced was 47.5 g, stirring was started, and the mixture was warmed to 50°C and reacted for 6 h. After the reaction was completed, the reaction liquid obtained was distilled to remove the methanol, and 93.0 g of intermediate difluoroacetoacetic acid was obtained.

[0031] S202: 202 g of a 10% by mass sodium hydroxide solution was added to a reaction bottle, and stirring was started. Ethyl difluoroacetoacetate was added dropwise to the sodium hydroxide solution, and after warming to 60°C, hydrochloric acid was added dropwise to adjust the pH to 4, and the reaction was allowed to proceed for 2 h to obtain a reaction liquid.

[0032] S203: After the reaction liquid was cooled to room temperature, 281.4 g of the reaction liquid was transferred to a separatory funnel, and 249 mL of ethyl acetate was added for extraction. After the extraction was completed, the layers were allowed to separate, the organic phase was collected, and phosphorus pentoxide was added to the organic phase for drying. The dried organic phase was transferred to a batch rectification column, and rectification was performed under normal pressure, with a reflux ratio of 5:1, a column bottom temperature of 66.8°C, and a column top temperature of 59.8°C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0033] Example 3 The embodiment of the present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S301: 83.1 g of ethyl 4,4-difluoroacetoacetate, 166.4 g of 1-fluoropyridine tetrafluoroborate, and 130 mL of tetrahydrofuran were added to a reaction bottle, stirring was started, and the mixture was warmed to 70°C and reacted for 5 h. After the reaction was completed, the reaction liquid obtained was distilled to remove the tetrahydrofuran, and 88.9 g of intermediate difluoroacetoacetic acid was obtained.

[0034] S302: 334 g of a 20% by mass potassium carbonate solution was added to a reaction bottle, and stirring was started. Ethyl difluoroacetoacetate was added dropwise to the potassium carbonate solution, and after warming to 70°C, phosphoric acid was added dropwise to adjust the pH to 5, and the reaction was allowed to proceed for 1.5 h to obtain a reaction liquid.

[0035] S303: After the reaction liquid was cooled to room temperature, 410.4 g of the reaction liquid was transferred to a separatory funnel, and 363 mL of methyl tert-butyl ether was added for extraction. After the extraction was completed, the layers were allowed to separate, the organic phase was collected, and anhydrous sodium sulfate was added to the organic phase for drying. The dried organic phase was transferred to a batch rectification column, and rectification was performed under normal pressure, with a reflux ratio of 5:1, a column bottom temperature of 71.8°C, and a column top temperature of 63.8°C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0036] Example 4 The embodiment of the present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S401: 83.1g of 4,4-difluoroacetyl ethyl acetate, 315.3g of N-fluorobenzene sulfonimide and 160mL of acetonitrile are added into a reaction bottle, stirring and mixing are started, and temperature is raised to 90 DEG C and kept for 3h. After reaction, temperature is lowered to room temperature, and the reaction liquid obtained by reaction is distilled to distill acetonitrile, and 85.9g of intermediate difluoroacetyl difluoroacetic acid is obtained.

[0037] S402: 330g of a sodium carbonate solution with a mass concentration of 15% is added into the reaction bottle, and stirring is started. The difluoroacetyl difluoroacetic acid ethyl ester is added dropwise into the sodium carbonate solution, nitric acid is added dropwise after temperature is raised to 60 DEG C, pH value is adjusted to 4, and reaction is kept for 2h to obtain a reaction liquid.

[0038] S403: After the reaction liquid is lowered to room temperature, 403.1g of the reaction liquid is transferred into a separatory funnel, 355mL of ether is added for extraction. After extraction, the liquid is separated, the organic phase is collected, and 5A molecular sieve is added into the organic phase for drying. The dried organic phase is transferred into a batch rectification tower, and rectification is carried out under the conditions of normal pressure, a reflux ratio of 5:1, a tower bottom temperature of 66.8 DEG C and a tower top temperature of 63.8 DEG C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0039] Example 5 The embodiment of the present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S501: 83.1g of 4,4-difluoroacetyl ethyl acetate, 284.2g of N-fluoropyridine triflate and 150mL of hexafluorobenzene are added into a reaction bottle, stirring and mixing are started, and temperature is raised to 80 DEG C and kept for 5h. After reaction, temperature is lowered to room temperature, and the reaction liquid obtained by reaction is distilled to distill hexafluorobenzene, and 92.0g of intermediate difluoroacetyl difluoroacetic acid is obtained.

[0040] S502: 200g of a lithium hydroxide solution with a mass concentration of 6% is added into the reaction bottle, and stirring is started. The difluoroacetyl difluoroacetic acid ethyl ester is added dropwise into the lithium hydroxide solution, nitric acid is added dropwise after temperature is raised to 40 DEG C, pH value is adjusted to 2, and reaction is kept for 5h to obtain a reaction liquid.

[0041] S503: After the reaction solution is cooled to room temperature, 278.6 g of the reaction solution is transferred to a separatory funnel, 246 mL of methyl tert-butyl ether is added for extraction. After the extraction is completed, the layers are allowed to separate, the organic phase is collected, and anhydrous calcium chloride is added to the organic phase for drying. The dried organic phase is transferred to a batch rectification column, and rectification is performed under normal pressure, with a reflux ratio of 5:1, a column bottom temperature of 71.8°C, and a column top temperature of 59.8°C, to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0042] Example 6 The example of the present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S601: 83.1 g of ethyl 4,4-difluoroacetoacetate, 319.8 g of 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octane tetrafluoroborate, and 170 mL of water are added to a reaction bottle, stirring and mixing are started, and the temperature is raised to 85°C for 3.5 h of incubation. After the reaction is completed, the temperature is lowered to room temperature, and the reaction solution obtained by the reaction is distilled to remove water, to obtain 93.0 g of intermediate difluoroacetyl difluoroacetic acid.

[0043] S602: 305 g of a 11% mass concentration potassium hydroxide solution is added to the reaction bottle, and stirring is started. The ethyl difluoroacetyl difluoroacetate is added dropwise to the potassium hydroxide solution, the temperature is raised to 50°C, and then nitric acid is added dropwise to adjust the pH value to 6, and incubation is performed for 3 h to obtain a reaction solution.

[0044] S603: After the reaction solution is cooled to room temperature, 386.0 g of the reaction solution is transferred to a separatory funnel, 340 mL of propyl ether is added for extraction. After the extraction is completed, the layers are allowed to separate, the organic phase is collected, and anhydrous magnesium sulfate is added to the organic phase for drying. The dried organic phase is transferred to a batch rectification column, and rectification is performed under normal pressure, with a reflux ratio of 5:1, a column bottom temperature of 68°C, and a column top temperature of 62°C, to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0045] Example 7 The example of the present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S701: 83.1 g of ethyl 4,4-difluoroacetoacetate, 389.7 g of 1-chloromethyl-4-fluoro-1,4-diazabicyclo[2.2.2]octane di(tetrafluoroborate), and 190 mL of toluene are added to a reaction bottle, stirring and mixing are started, and the temperature is raised to 120°C for 1 h of incubation. After the reaction is completed, the temperature is lowered to room temperature, and the reaction solution obtained by the reaction is distilled to remove toluene, to obtain 92.0 g of intermediate difluoroacetyl difluoroacetic acid.

[0046] S702: 341 g of 8% sodium hydroxide solution was added to the reaction bottle, and stirring was started. Ethyl difluoroacetyldifluoroacetate was added dropwise to the sodium hydroxide solution, and after being heated to 60°C, nitric acid was added dropwise to adjust the pH value to 4, and the reaction was kept for 2 h to obtain a reaction solution.

[0047] S703: After the reaction solution was cooled to room temperature, 431.1 g of the reaction solution was transferred to a separatory funnel, 381 mL of methyl tert-butyl ether was added for extraction. After the extraction was completed, the layers were allowed to separate, the organic phase was collected, and anhydrous calcium chloride was added to the organic phase for drying. The dried organic phase was transferred to a batch rectification column, and rectification was carried out under normal pressure, with a reflux ratio of 5:1, a column bottom temperature of 69°C, and a column top temperature of 60°C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0048] Example 8 The embodiments of the present application provide a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S801: 83.1 g of ethyl 4,4-difluoroacetoacetate, 212.6 g of 1-fluoropyridine tetrafluoroborate, and 200 mL of trifluorotoluene were added to a reaction bottle, stirring was started, the temperature was increased to 11°C, and the reaction was kept for 1.5 h. After the reaction was completed, the temperature was decreased to room temperature, and the reaction solution obtained was distilled to remove the trifluorotoluene to obtain 94.0 g of intermediate difluoroacetyldifluoroacetic acid.

[0049] S802: 558 g of 6% sodium hydroxide solution was added to the reaction bottle, and stirring was started. Ethyl difluoroacetyldifluoroacetate was added dropwise to the sodium hydroxide solution, and after being heated to 70°C, sulfuric acid was added dropwise to adjust the pH value to 5, and the reaction was kept for 1.5 h to obtain a reaction solution.

[0050] S803: After the reaction solution was cooled to room temperature, 666.1 g of the reaction solution was transferred to a separatory funnel, 590 mL of ethyl acetate was added for extraction. After the extraction was completed, the layers were allowed to separate, the organic phase was collected, and 5A molecular sieves were added to the organic phase for drying. The dried organic phase was transferred to a batch rectification column, and rectification was carried out under normal pressure, with a reflux ratio of 5:1, a column bottom temperature of 70°C, and a column top temperature of 62°C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0051] Example 9 The embodiments of the present application provide a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S901: 83.1 g of ethyl 4,4-difluoroacetoacetate, 331.1 g of N-fluorobenzene sulfonimide and 180 mL of tetrahydrofuran were added into a reaction bottle, the mixture was stirred and mixed, and then was warmed to 70 DEG C for 5 h. After the reaction was completed, the reaction liquid was distilled to remove the tetrahydrofuran, and 96.4 g of intermediate difluoroacetoacetic acid was obtained.

[0052] S902: 527 g of 5% potassium hydroxide solution was added into a reaction bottle, and then the stirring was started. The ethyl difluoroacetoacetate was added into the potassium hydroxide solution dropwise, and then nitric acid was added dropwise after the temperature was warmed to 80 DEG C, so as to adjust the pH value to 4, and then the reaction was carried out for 1 h to obtain a reaction liquid.

[0053] S903: After the reaction liquid was cooled to room temperature, 601.1 g of the reaction liquid was transferred into a separatory funnel, and then 530 mL of methyl tert-butyl ether was added for extraction. After the extraction was completed, the liquid was allowed to stand to separate into two layers, the organic phase was collected, and then anhydrous calcium chloride was added into the organic phase for drying. The dried organic phase was transferred into a batch rectification tower, and then was rectified under normal pressure, with a reflux ratio of 5:1, a tower bottom temperature of 71 DEG C and a tower top temperature of 63 DEG C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0054] Example 10 The embodiment of the present application provides a synthesis method of 1,1,3,3-tetrafluoro-2-propanone, which comprises the following steps: S1001: 83.1 g of ethyl 4,4-difluoroacetoacetate, 308.9 g of N-fluoropyridine triflate, 100 mL of acetonitrile and 70 mL of methanol were added into a reaction bottle, the mixture was stirred and mixed, and then was warmed to 90 DEG C for 3 h. After the reaction was completed, the reaction liquid was distilled to remove the acetonitrile and methanol, and then 87.9 g of intermediate difluoroacetoacetic acid was obtained.

[0055] S1002: 160 g of 12% sodium hydroxide solution was added into a reaction bottle, and then the stirring was started. The ethyl difluoroacetoacetate was added into the sodium hydroxide solution dropwise, and then nitric acid was added dropwise after the temperature was warmed to 60 DEG C, so as to adjust the pH value to 3, and then the reaction was carried out for 2 h to obtain a reaction liquid.

[0056] S1003: After the reaction liquid was cooled to room temperature, 234.3 g of the reaction liquid was transferred into a separatory funnel, and then 207 mL of ether was added for extraction. After the extraction was completed, the liquid was allowed to stand to separate into two layers, the organic phase was collected, and then anhydrous sodium sulfate was added into the organic phase for drying. The dried organic phase was transferred into a batch rectification tower, and then was rectified under normal pressure, with a reflux ratio of 10:1, a tower bottom temperature of 67 DEG C and a tower top temperature of 60 DEG C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0057] Example 11 The present invention provides a method for synthesizing 1,1,3,3-tetrafluoro-2-acetone, which comprises: S1101: Add 83.1 g of ethyl 4,4-difluoroacetoacetate, 351.8 g of Selectfluor II reagent, and 200 mL of dichloromethane to a reaction flask, initiate stirring, and heat to 60°C for 6 hours. After the reaction is complete, cool to room temperature and distill the resulting reaction solution to remove the dichloromethane, yielding 88.9 g of the intermediate difluoroacetyldifluoroacetic acid.

[0058] S1102: Add 388 g of 7% potassium hydroxide solution to the reaction flask and start stirring. Add ethyl difluoroacetyl difluoroacetate dropwise to the potassium hydroxide solution. Raise the temperature to 40°C and then add nitric acid dropwise to adjust the pH to 1. Keep the temperature for 5 hours to obtain a reaction solution.

[0059] S1103: After the reaction solution cools to room temperature, 463.6 g of the reaction solution is transferred to a separatory funnel and 410 mL of ethyl acetate is added for extraction. After the extraction is completed, the mixture is allowed to stand and the layers are separated. The organic phase is collected and dried by adding anhydrous magnesium sulfate. The dried organic phase is transferred to a batch distillation tower and distilled under normal pressure, a reflux ratio of 1:1, a bottom temperature of 70°C, and a top temperature of 61°C to obtain 1,1,3,3-tetrafluoro-2-propanone.

[0060] In the present embodiment, the 1,1,3,3-tetrafluoro-2-acetone prepared in Example 1 was subjected to nuclear magnetic resonance detection to obtain the attached Figure 1 . Figure 1 It can be seen that the product obtained in Example 1 is 1,1,3,3-tetrafluoro-2-propanone.

[0061] In addition, the purity and yield of 1,1,3,3-tetrafluoro-2-propanone prepared in Examples 1-11 were also tested in this application, and Table 1 was obtained. The purity was tested by gas chromatography area normalization method, and the yield was calculated as (actual product weight / theoretical product weight) × 100%.

[0062] Table 1: Purity and yield of 1,1,3,3-tetrafluoro-2-acetone prepared in various examples As can be seen from Table 1, the purity of 1,1,3,3-tetrafluoro-2-propanone prepared in the examples of the present application reached more than 97.8%, with a maximum of 98.5%; the yield reached more than 77.4%.

[0063] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for synthesizing 1,1,3,3-tetrafluoro-2-acetone, characterized in that: include: Ethyl 4,4-difluoroacetoacetate, a fluorination agent, and a solvent are mixed and subjected to a fluorination reaction to generate ethyl difluoroacetyl difluoroacetate; The ethyl difluoroacetyl difluoroacetate is subjected to hydrolysis and decarboxylation to obtain a reaction solution; The reaction liquid is subjected to extraction, drying and atmospheric distillation to obtain 1,1,3,3-tetrafluoro-2-acetone.

2. The method for synthesizing 1,1,3,3-tetrafluoro-2-acetone according to claim 1, characterized in that: The fluorination reaction temperature is 50-150° C., and the reaction time is 1-6 hours. After the fluorination reaction is completed, the mixture is cooled to room temperature and the solvent is distilled to obtain the ethyl difluoroacetyl difluoroacetate.

3. The method for synthesizing 1,1,3,3-tetrafluoro-2-acetone according to claim 1, characterized in that: The hydrolysis and decarboxylation of ethyl difluoroacetyl difluoroacetate to obtain a reaction solution comprises: dropping ethyl difluoroacetyl difluoroacetate into an alkaline solution, heating the solution to 40-80° C., adjusting the pH value to acidic, and maintaining the temperature for 1-5 hours to obtain a reaction solution.

4. The method for synthesizing 1,1,3,3-tetrafluoro-2-acetone according to claim 1, characterized in that: The molar ratio of the ethyl 4,4-difluoroacetoacetate to the fluorination agent is 1:1.8-1:2.

6.

5. The method for synthesizing 1,1,3,3-tetrafluoro-2-acetone according to claim 1, characterized in that: The fluorination reagent includes one or more of fluorine gas diluted with nitrogen, 1-chloromethyl-4-fluoro-1,4-diazabicyclo[2.2.2]octane di(tetrafluoroborate), 1-fluoro-4-methyl-1,4-diazabicyclo[2.2.2]octane tetrafluoroborate, 1-fluoropyridine tetrafluoroborate, N-fluorobisbenzenesulfonimide, and N-fluoropyridine trifluoromethanesulfonate; and the solvent includes one or more of tetrahydrofuran, acetonitrile, toluene, dichloromethane, methanol, trifluorotoluene, water, and hexafluorobenzene.

6. The method for synthesizing 1,1,3,3-tetrafluoro-2-propanone according to claim 3, characterized in that: The molar ratio of the ethyl difluoroacetyl difluoroacetate to the alkaline solution is 1:1-1:2; the alkaline solution includes an aqueous solution of sodium carbonate, potassium carbonate, sodium hydroxide, potassium hydroxide or lithium hydroxide.

7. The method for synthesizing 1,1,3,3-tetrafluoro-2-propanone according to claim 3, characterized in that: Acid is used to adjust the pH value to 1-6, wherein the acid includes one or more of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid, hydrobromic acid, and hydroiodic acid.

8. The method for synthesizing 1,1,3,3-tetrafluoro-2-acetone according to claim 1, characterized in that: The extraction agent used for the extraction includes one or more of ethyl acetate, ethyl ether, propyl ether, dichloromethane, and methyl tert-butyl ether.

9. The method for synthesizing 1,1,3,3-tetrafluoro-2-propanone according to claim 1, characterized in that: The desiccant used for drying includes one or more of anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride, phosphorus pentoxide, and 5A molecular sieve.

10. The method for synthesizing 1,1,3,3-tetrafluoro-2-propanone according to claim 1, characterized in that: The reflux ratio of the atmospheric distillation is 10:1-1:1, the tower bottom temperature is 66.8-71.8°C, and the tower top temperature is 59.8-63.8°C.

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