Synthesis process of alkyl 2-fluoroacrylate
Through the fluorination reaction of alkyl epoxy propionate with fluorination reagent and subsequent alkaline compound reaction, the synthesis yield of 2-fluorinated alkyl acrylate was successfully improved, the cost and three waste amount were reduced, and the process was simplified and efficient production was achieved.
Patent Information
- Application Number
- CN202411794779.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-09
- Publication Date
- 2025-03-25
AI Technical Summary
The existing synthesis process of alkyl 2-fluorofluoroacrylate has low yield, high cost, and large waste amount.
The fluorination reaction was carried out by contacting the alkyl epoxy propionate with a fluorination reagent to form an alkyl 2,3-difluoropropionate, and then reacted with an alkaline compound to obtain an alkyl 2-fluoroacrylate.
The process flow is short, simple, high yield and small amount of waste, which solves the problems of high cost and high waste of existing processes.
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Figure CN119684120A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a synthesis process of 2-fluoroalkyl acrylate. Background Art
[0002] 2-Alkyl fluoroacrylate is an important fluorine-containing monomer, mainly used in plastic optical fiber monomers and fine chemicals such as synthetic fluoroproline derivatives. Plastic optical fiber has the advantages of fast data transmission, low cost and high strength of glass optical fiber, and has a large market for data transmission systems in automobiles and aviation. Conventional plastic optical fibers such as polymethyl methacrylate and polystyrene on the market are currently limited in their application in the field of data transmission due to their poor thermal stability and high attenuation in the infrared and near-infrared regions.
[0003] The glass transition temperature of 2-fluoromethyl acrylate polymer is as high as 128°C. If a fluorine-containing group is introduced into its side chain, its glass transition temperature can reach 140°C, which meets the requirements for use under high temperature. At the same time, the spectral band and comprehensive spectral band of the carbon-fluorine bond are outside the relevant range, reducing the attenuation of the near-infrared. Therefore, 2-fluoroalkyl acrylate polymer has important uses in optical fiber materials.
[0004] There are many synthetic routes for 2-fluoroalkyl acrylates. Among the existing technologies, the main ones with industrial prospects are the fluoroacetate method and the 2-fluoropropionate method. Among them, the fluoroacetate method uses fluoroacetate and dimethyl oxalate as raw materials, undergoes Claisen condensation in the presence of a base, and then reacts with paraformaldehyde to produce 2-fluoroacrylate; this process has problems such as high toxicity of the raw material methyl fluoroacetate, low reaction yield, and large amount of three wastes. The 2-fluoropropionate method uses methyl 2-fluoropropionate as the starting material, is brominated with a brominating agent NBS, and then dehydrobrominated in the presence of an acid-binding agent DBU to produce 2-fluoroacrylate. This process is long, and there are problems such as the high price of the brominating agent NBS and high production cost. Summary of the invention
[0005] The present application provides a synthesis process of 2-fluoroalkyl acrylate, aiming to solve the problems of low yield, high cost and large amount of three wastes in the prior art synthesis process of 2-fluoroalkyl acrylate.
[0006] The present application provides a synthesis process of 2-fluoroalkyl acrylate, comprising the following steps:
[0007] (1) contacting an alkyl epoxypropionate with a fluorinating agent to carry out a fluorination reaction to obtain an alkyl 2,3-difluoropropionate;
[0008] (2) Releasing 2,3-difluoropropionic acid alkyl ester with a basic compound to obtain 2-fluoroacrylate alkyl ester.
[0009] The synthesis process of 2-fluoroalkyl acrylate described in the present application uses a fluorination agent to fluorinate alkyl epoxypropionate to generate 2,3-difluoroalkyl propionate, and 2,3-difluoroalkyl propionate is dehydrofluorinated to generate 2-fluoroalkyl acrylate, which has the advantages of short process flow, simple process, high yield, and less three wastes.
[0010] According to some embodiments of the synthesis process of 2-fluoro alkyl acrylate described in the present application, in step (1), the structural formula of the alkyl epoxypropionate is as shown below:
[0011]
[0012] Wherein R is a C1-C8 straight chain or branched alkyl group, a C6-C8 aryl group, or a C3-C8 cycloalkyl group which is substituted or unsubstituted with a heteroatom.
[0013] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the heteroatom substituent includes one or more of a halogen, an oxygen atom, a nitrogen atom and a sulfur atom.
[0014] According to some embodiments of the synthesis process of 2-fluoroacrylate alkyl ester described in the present application, R includes one or more of methyl, ethyl, propyl, butyl, cyclohexyl, phenyl, benzyl, phenethyl, difluoroethyl, trifluoroethyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 4-chlorophenyl, 3-oxabutyl, 3,6-dioxaheptyl and N,N-dimethylaminoethyl.
[0015] According to some embodiments of the synthesis process of 2-fluoroacrylate alkyl ester described in the present application, the fluorination agent includes one or more of N,N-dimethyl-1,1,2,2-tetrafluoroethylamine, N,N-dimethyl-1,1,2,3,3,3-hexafluoropropylamine and N,N-dimethyl-1,1,2-trifluoro-2-chloroethylamine, N,N-diethyl-1,1,2,2-tetrafluoroethylamine, N,N-diethyl-1,1,2,3,3,3-hexafluoropropylamine and N,N-diethyl-1,1,2-trifluoro-2-chloroethylamine.
[0016] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the fluorination reaction is carried out in the presence of a catalyst, and the catalyst includes a protonic acid and / or a Lewis acid.
[0017] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the catalyst includes one or more of boron trifluoride, hydrogen fluoride, antimony trifluoride, antimony pentafluoride, antimony pentachloride, titanium tetrafluoride, aluminum trichloride and zinc fluoride.
[0018] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the fluorination reaction is carried out in the presence of a first solvent or without a solvent; preferably, the first solvent includes an amide solvent, an ether solvent or a nitrile solvent.
[0019] According to some embodiments of the synthesis process of 2-fluoroacrylate alkyl ester described in the present application, the first solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, methyltetrahydrofuran, acetonitrile, benzonitrile and diethyl ether.
[0020] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the molar ratio of the alkyl epoxypropionate to the fluorination agent is 1:(0.9-2).
[0021] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the mass ratio of the alkyl epoxypropionate to the catalyst is 1:(0.05-0.3).
[0022] According to some embodiments of the synthesis process of alkyl 2-fluoroacrylate described in the present application, the mass ratio of the alkyl epoxypropionate to the first solvent is 1:(0-5).
[0023] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the temperature of the fluorination reaction is 20-120° C., and the time of the fluorination reaction is 2-20 h.
[0024] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, in step (2), the basic compound includes an inorganic base, an organic base or an alkoxy alkali metal salt corresponding to the alkyl group in the alkyl epoxypropionate.
[0025] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the inorganic base includes potassium carbonate and / or sodium carbonate.
[0026] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the organic base includes one or more of triethylamine, tetramethylethylenediamine, 1,8-diazabicyclo[5,4,0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, dimethylcyclohexylamine and pyridine.
[0027] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the alkali metal alkoxide salt includes one or more of sodium methoxide, potassium methoxide, sodium trifluoroethoxide, potassium ethoxide and sodium ethoxide.
[0028] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the 2,3-difluoroalkyl propionate and the basic compound are mixed in a second solvent.
[0029] According to some embodiments of the process for synthesizing 2-fluoroalkyl acrylate described herein, the second solvent includes an aprotic solvent.
[0030] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the aprotic solvent includes one or more of an amide solvent, a sulfone solvent, a sulfoxide solvent, an ether solvent and a nitrile solvent.
[0031] According to some embodiments of the synthesis process of 2-fluoroacrylate alkyl ester described in the present application, the second solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, cyclopentane, N-methylpyrrolidone, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether, acetonitrile and benzonitrile.
[0032] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the molar ratio of the 2,3-difluoroalkyl propionate to the basic compound is 1:(1-2).
[0033] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the mass ratio of the 2,3-difluoroalkyl propionate to the second solvent is 1:(2-20).
[0034] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, in step (2), the reaction temperature is 50-100° C., and the reaction time is 2-8 h.
[0035] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the absolute pressure of the reaction is 5 kPa-100 kPa.
[0036] According to some embodiments of the synthesis process of 2-fluoroalkyl acrylate described in the present application, the synthesis process also includes extracting 2-fluoroalkyl acrylate from the reaction product of 2,3-difluoroalkyl propionate and a basic compound, and the extraction method includes reactive distillation coupling or distillation separation. BRIEF DESCRIPTION OF THE DRAWINGS
[0037] Figure 1 This is the mass spectrum of methyl 2-fluoroacrylate obtained by the synthesis process of alkyl 2-fluoroacrylate described in Example 1 of the present application. DETAILED DESCRIPTION
[0038] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.
[0039] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.
[0040] The present invention provides a synthesis process of 2-fluoroalkyl acrylate, comprising the following steps:
[0041] (1) contacting an alkyl epoxypropionate with a fluorinating agent to carry out a fluorination reaction to obtain an alkyl 2,3-difluoropropionate;
[0042] (2) Releasing 2,3-difluoropropionic acid alkyl ester with a basic compound to obtain 2-fluoroacrylate alkyl ester.
[0043] The alkyl epoxypropionate generates an oxonium ion under the action of a catalyst, and the oxonium ion generates an alkyl 2,3-difluoropropionate under the action of a fluorination agent described in the present application; the alkyl 2,3-difluoropropionate then undergoes a dehydrofluorination reaction in the presence of an alkaline compound to generate an alkyl 2-fluoroacrylate. The alkyl epoxypropionate can be obtained by oxidizing methyl acrylate with sodium hypochlorite. The synthesis process of the alkyl 2-fluoroacrylate described in the present application has the advantages of convenient raw material sources, short process steps, and high reaction yield.
[0044] In some embodiments of the present application, in step (1), the structural formula of the alkyl epoxypropionate is as shown below:
[0045]
[0046] Wherein R is a C1-C8 straight or branched alkyl group, a C6-C8 aryl group, or a C3-C8 cycloalkyl group which is substituted or unsubstituted with a heteroatom; preferably, the heteroatom substituent includes one or more of a halogen, an oxygen atom, a nitrogen atom, and a sulfur atom.
[0047] In some embodiments of the present application, R includes one or more of methyl, ethyl, propyl, butyl, cyclohexyl, phenyl, benzyl, phenethyl, difluoroethyl, trifluoroethyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 4-chlorophenyl, 3-oxabutyl, 3,6-dioxaheptyl and N,N-dimethylaminoethyl.
[0048] In some embodiments of the present application, the fluorination agent includes one or more of N,N-dimethyl-1,1,2,2-tetrafluoroethylamine, N,N-dimethyl-1,1,2,3,3,3-hexafluoropropylamine and N,N-dimethyl-1,1,2-trifluoro-2-chloroethylamine, N,N-diethyl-1,1,2,2-tetrafluoroethylamine, N,N-diethyl-1,1,2,3,3,3-hexafluoropropylamine and N,N-diethyl-1,1,2-trifluoro-2-chloroethylamine. The fluorination agent used in the present application can convert epoxides into ortho-difluorides with high selectivity and generate corresponding amides at the same time. The fluorination agent described in the present application can be obtained in high yield by addition reaction of dimethylamine or diethylamine with fluorinated olefins such as tetrafluoroethylene, hexafluoropropylene, and trifluorochloroethylene, which is low in price, convenient for industrial production, and low in cost; at the same time, the fluorination agent is liquid and easy to use.
[0049] In some embodiments of the present application, the fluorination reaction is carried out in the presence of a catalyst, and the catalyst includes a protonic acid and / or a Lewis acid.
[0050] In some embodiments of the present application, the catalyst includes one or more of boron trifluoride, hydrogen fluoride, antimony trifluoride, antimony pentafluoride, antimony pentachloride, titanium tetrafluoride, aluminum trichloride and zinc fluoride. The catalyst described in the present application can enhance the nucleophilic attack ability of the fluorination agent and effectively promote the cleavage of the epoxy bond.
[0051] In some embodiments of the present application, the fluorination reaction is carried out in the presence of a first solvent or without a solvent; preferably, the first solvent includes an amide solvent, an ether solvent or a nitrile solvent. The presence of the first solvent can effectively improve the reaction yield.
[0052] In some embodiments of the present application, the first solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, methyltetrahydrofuran, acetonitrile, benzonitrile and diethyl ether.
[0053] In some embodiments of the present application, the molar ratio of the alkyl glycidyl ester to the fluorinating agent is 1:(0.9-2), such as 1:0.9, 1:0.98, 1:1.02, 1:1.2, 1:1.5, 1:1.8, 1:2, etc. If the amount of the fluorinating agent is small, the alkyl glycidyl ester will be incompletely fluorinated and the conversion rate will be low; if the amount of the fluorinating agent is too large, it will cause economic waste. The fluorinating agent can be added all at once or continuously in a dropwise manner.
[0054] In some embodiments of the present application, the mass ratio of the alkyl epoxypropionate to the catalyst is 1:(0.05-0.3), for example, 1:0.05, 1:0.08, 1:0.1, 1:0.15, 1:0.2, 1:0.26, 1:0.3, etc.
[0055] In some embodiments of the present application, the mass ratio of the alkyl epoxypropionate and the first solvent is 1:(0-5), for example, 1:0.01, 1:0.5, 1:1, 1:2, 1:2.6, 1:3.2, 1:4.8, 1:5, etc.
[0056] In some embodiments of the present application, the temperature of the fluorination reaction is 20-120°C, such as 20°C, 25°C, 38°C, 46°C, 59°C, 70°C, 85°C, 93°C, 100°C, 108°C, 115°C, 120°C, etc., and the time of the fluorination reaction is 2-20h, such as 2h, 8h, 12h, 16h, 20h, etc. If the reaction temperature of the fluorination reaction is too high, the reaction speed will be accelerated, but it will also promote the increase of side reactions, resulting in a decrease in the reaction selectivity; if the reaction temperature is too low, the reaction speed will be slow.
[0057] In some embodiments of the present application, after the fluorination reaction is completed, the unreacted fluorination agent can be removed by washing with water or alkali, preferably washing with saturated sodium bicarbonate solution. After washing, the layers are separated and the product 2,3-difluoropropionic acid alkyl ester is separated by distillation of the organic phase.
[0058] In some embodiments of the present application, in step (2), the basic compound includes an inorganic base, an organic base or an alkali metal alkoxide corresponding to the alkyl group in the alkyl epoxypropionate. In step (2), the raw material 2,3-difluoropropionic acid alkyl ester can be added to the reaction system at one time or by continuous dropwise addition. Continuous dropwise addition can reduce the accumulation of the raw material in the reaction system, reduce the raw material concentration, and reduce side reactions.
[0059] In some embodiments of the present application, the inorganic base includes potassium carbonate and / or sodium carbonate. Inorganic strong bases containing hydroxide such as sodium hydroxide and potassium hydroxide are prone to hydrolysis reaction with alkyl 2,3-difluoropropionate, resulting in ester bond breakage and reduced selectivity; therefore, the inorganic base is preferably an alkaline compound without hydroxide such as potassium carbonate and sodium carbonate.
[0060] In some embodiments of the present application, the organic base includes one or more of triethylamine, tetramethylethylenediamine, 1,8-diazabicyclo[5,4,0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, dimethylcyclohexylamine and pyridine. Monoalkylamine, dialkylamine and the like are easy to react with esters to form amides, so the organic base is preferably a base that is not easy to react with ester bonds.
[0061] In some embodiments of the present application, the alkoxy alkali metal salt includes one or more of sodium methoxide, potassium methoxide, sodium trifluoroethoxide, potassium ethoxide and sodium ethoxide.
[0062] In some embodiments of the present application, the 2,3-difluoropropionic acid alkyl ester and the basic compound are mixed in a second solvent; preferably, the second solvent includes an aprotic solvent.
[0063] In some embodiments of the present application, the aprotic solvent includes one or more of an amide solvent, a sulfone solvent, a sulfoxide solvent, an ether solvent and a nitrile solvent.
[0064] In some embodiments of the present application, the second solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, cyclopentane sulfone, N-methylpyrrolidone, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether, acetonitrile and benzonitrile.
[0065] In some embodiments of the present application, the molar ratio of the alkyl 2,3-difluoropropionate to the basic compound is 1:(1-2), such as 1:1, 1:1.2, 1:1.6, 1:1.8, 1:2, etc. If the amount of the basic compound is small, the reaction of the raw material alkyl 2,3-difluoropropionate is incomplete and the conversion rate is low; if the amount of the basic compound is large, the reaction of the alkyl 2,3-difluoropropionate is complete, and the large amount of base is not economical.
[0066] In some embodiments of the present application, the mass ratio of the 2,3-difluoropropionic acid alkyl ester to the second solvent is 1:(2-20), for example, 1:2, 1:8, 1:12, 1:16, 1:20, etc.
[0067] In some embodiments of the present application, in step (2), the reaction temperature is 50-100°C, such as 50°C, 60°C, 75°C, 82°C, 93°C, 100°C, etc., and the reaction time is 2-8h, such as 2h, 4h, 6h, 8h, etc. If the reaction temperature is too high, it will lead to an increase in side reactions, and if the reaction temperature is too low, the reaction is incomplete and the reaction time is long.
[0068] In some embodiments of the present application, the absolute pressure of the reaction is 5 kPa-100 kPa, for example, 5 kPa, 20 kPa, 35 kPa, 43 kPa, 56 kPa, 68 kPa, 72 kPa, 86 kPa, 91 kPa, 100 kPa, etc.
[0069] In some embodiments of the present application, the product 2-fluoroacrylate alkyl ester can be removed from the reaction system by reaction-distillation coupling, that is, by reacting and distilling at the same time, or it can be separated by distillation after the reaction is completed; reaction-distillation coupling can shorten the residence time of the product in the reaction system, reduce side reactions such as hydrolysis and polymerization of 2-fluoroacrylate alkyl ester, and improve the reaction yield.
[0070] The technical solution of the present application is further introduced below in conjunction with specific embodiments.
[0071] Example 1
[0072] A synthesis process of 2-fluoroalkyl acrylate comprises the following steps:
[0073] In a 500mL four-necked flask with a condenser, add 51g (0.5mol) of methyl epoxypropionate, 100g of anhydrous ether, and 5.5g of a 47% boron trifluoride ether solution, stir, and drop 94.3g (0.65mol) of N,N-dimethyl-1,1,2,2-tetrafluoroethylamine at 20°C for 2h, and then react at 20°C for 18h. After the reaction is completed, add 100g of saturated sodium bicarbonate aqueous solution for washing, layering, and rectifying the organic phase to obtain 52g of methyl 2,3-difluoropropionate, with a yield of 84% and a purity of 99.5%.
[0074] In a 1000mL four-necked flask with a distillation column and a constant pressure funnel, add 500g N,N-dimethylformamide and 79g (0.52mol) 1,8-diazabicyclo[5,4,0]-7-undecene, and stir. Place 49.6g (0.4mol) methyl 2,3-difluoropropionate in the constant pressure funnel, evacuate the system to an absolute pressure of 48kPa, raise the temperature to 70°C, and add methyl 2,3-difluoropropionate dropwise to the four-necked flask within 2h. As methyl 2,3-difluoropropionate is added, material is continuously evaporated from the top of the distillation column. When methyl 2,3-difluoropropionate is added, continue to keep warm for 2h until no material evaporates. The distilled material was collected to obtain 38.8 g of methyl 2-fluoroacrylate with a content of 98.6% and a yield of 92%. The obtained methyl 2-fluoroacrylate was distilled to obtain methyl 2-fluoroacrylate with a purity of 99.9%.
[0075] Example 2
[0076] A synthesis process of 2-fluoroalkyl acrylate comprises the following steps:
[0077] In a 1000mL four-necked flask with a condenser, add 85g (0.5mol) of 2,2,2-trifluoroethyl epoxypropionate and 400g of N,N-dimethylacetamide, stir, slowly add 107g (0.55mol) of N,N-dimethyl-1,1,2,3,3,3-hexafluoropropylamine and 8.5g of hydrogen fluoride, and react at 40°C for 12h. After the reaction, add 300g of saturated sodium bicarbonate aqueous solution, stir and wash for 1h, separate the layers, and distill the organic phase to obtain 78.7g of 2,3-difluoropropionic acid-2,2,2-trifluoroethyl ester, with a yield of 82% and a purity of 99.6%.
[0078] In a 2000mL four-necked flask with a distillation column and a constant pressure funnel, add 1500g of diethylene glycol dimethyl ether and 73.2g (0.6mol) of sodium trifluoroethoxide, stir, charge 76.8g (0.4mol) of 2,3-difluoropropionic acid-2,2,2-trifluoroethyl ester into the constant pressure funnel, evacuate the system to an absolute pressure of 20kPa, raise the temperature to 50°C, and add 2,3-difluoropropionic acid-2,2,2-trifluoroethyl ester dropwise to the four-necked flask within 2h. As 2,3-difluoropropionic acid-2,2,2-trifluoroethyl ester is added, material is continuously evaporated from the top of the distillation column. After the addition of 2,3-difluoropropionic acid-2,2,2-trifluoroethyl ester, continue the reaction for 4h until no material is evaporated. A total of 107 g of a mixture of 2-fluoroacrylate-2,2,2-trifluoroethyl ester and trifluoroethanol was collected. The mixture was distilled to obtain 62 g of 2-fluoroacrylate-2,2,2-trifluoroethyl ester with a purity of 99.6% and a yield of 90%.
[0079] Example 3
[0080] A synthesis process of 2-fluoroalkyl acrylate comprises the following steps:
[0081] Add 85g (0.5mol) of cyclohexyl epoxypropionate to a 500mL four-necked flask with a condenser, stir, slowly add 12.7g of aluminum chloride, dropwise add 72.7g (0.45mol) of N,N-dimethyl-1,1,2-trifluoro-2-chloroethylamine within 1h, heat to 70°C, and react for 7h. After the reaction, add 100g of saturated sodium bicarbonate aqueous solution, stir and wash for 1h, separate layers, and distill the organic phase to obtain 72g of cyclohexyl 2,3-difluoropropionate, with a yield of 75% and a purity of 99.2%.
[0082] In a 1000mL four-necked flask with a constant pressure funnel, add 154g of acetonitrile and 55.4g (0.4mol) of potassium carbonate, stir, and put 76.8g (0.4mol) of 2,3-difluoropropionic acid cyclohexyl in the constant pressure funnel, heat to 80°C, and add 2,3-difluoropropionic acid cyclohexyl to the four-necked flask dropwise within 4h. After the addition of 2,3-difluoropropionic acid cyclohexyl, continue stirring and reacting for 4h. After the reaction is completed, cool, filter, and distill the filtrate to obtain 56.4g of 2-fluoroacrylate cyclohexyl, with a purity of 99.8% and a yield of 82%.
[0083] Example 4
[0084] A synthesis process of 2-fluoroalkyl acrylate comprises the following steps:
[0085] In a 1000mL four-necked flask with a condenser, add 89g (0.5mol) benzyl 2,3-epoxypropionate and 300g methyltetrahydrofuran, stir, slowly add 17.8g antimony pentachloride and 123g (0.85mol) N,N-dimethyl-1,1,2,2-tetrafluoroethylamine, control the temperature not to exceed 25°C, after adding, heat to 90°C and react for 4h. After the reaction is completed, add 200g saturated sodium bicarbonate aqueous solution, stir and wash for 1h, separate layers, and distill the organic phase to obtain 86g benzyl 2,3-difluoropropionate, with a yield of 86% and a purity of 99.6%.
[0086] In a 1000mL four-necked flask with a constant pressure funnel, add 400g of methyltetrahydrofuran and 84g (0.72mol) of tetramethylethylenediamine, stir, slowly add 80g (0.4mol) of 2,3-difluoropropionic acid benzyl ester, heat to 90°C, and react for 2h. After the reaction is completed, cool, filter, and distill the filtrate to obtain 57.6g of 2-fluoroacrylate benzyl ester with a purity of 99.4% and a yield of 80%.
[0087] Example 5
[0088] A synthesis process of 2-fluoroalkyl acrylate comprises the following steps:
[0089] In a 1000mL four-necked flask with a condenser, add 73g (0.5mol) 2,3-epoxypropionic acid-3-oxabutyl ester, 150g acetonitrile, stir, slowly add 195g (1mol) N,N-dimethyl-1,1,2,3,3,3-hexafluoropropylamine, 21.9g antimony trifluoride, after adding, heat to 120℃, react for 2h. After the reaction, add 100g saturated sodium bicarbonate aqueous solution, stir and wash for 1h, separate layers, and distill the organic phase to obtain 68g 2,3-difluoropropionic acid-3-oxabutyl ester, with a yield of 81% and a purity of 99.4%.
[0090] In a 2000mL four-necked flask with a distillation column and a constant pressure funnel, add 1000g of tetraethylene glycol dimethyl ether and 99.4g (0.8mol) of 1,5-diazabicyclo [4,3,0] -5-nonene, and stir. Place 67.2g (0.4mol) of 2,3-difluoropropionic acid-3-oxabutyl ester in the constant pressure funnel, evacuate the system to an absolute pressure of 8kPa, raise the temperature to 100°C, and add 2,3-difluoropropionic acid-3-oxabutyl ester dropwise to the four-necked flask within 4h. As 2,3-difluoropropionic acid-3-oxabutyl ester is added, material is continuously evaporated from the top of the distillation column. When 2,3-difluoropropionic acid-3-oxabutyl ester is added, continue the reaction for 4h until no material is evaporated. A total of 55 g of 3-oxabutyl 2-fluoroacrylate was collected, with a content of 98.0% and a yield of 91%.
[0091] Example 6
[0092] The synthesis process of a 2-fluoroalkyl acrylate described in Example 6 is different from that in Example 1 only in that the temperature of the fluorination reaction is different.
[0093] In the synthesis process of 2-fluoroalkyl acrylate described in Example 6, the temperature of the fluorination reaction is 40° C. 55 g of methyl 2,3-difluoropropionate, with a yield of 89% and a purity of 99.7%.
[0094] Example 7
[0095] The synthesis process of a 2-fluoroalkyl acrylate described in Example 7 is different from that in Example 1 only in that the temperature of the fluorination reaction is different.
[0096] In the synthesis process of 2-fluoroalkyl acrylate described in Example 7, the temperature of the fluorination reaction is 80° C. 56 g of methyl 2,3-difluoropropionate, with a yield of 90% and a purity of 99.6%.
[0097] Example 8
[0098] The synthesis process of a 2-fluoroalkyl acrylate described in Example 8 is different from that in Example 1 only in that the temperature of the fluorination reaction is different.
[0099] In the synthesis process of 2-fluoroalkyl acrylate described in Example 8, the temperature of the fluorination reaction is 100° C. 49 g of methyl 2,3-difluoropropionate, with a yield of 79% and a purity of 99.3%.
[0100] Comparative Example 1
[0101] The only difference between the synthesis process of a 2-fluoroalkyl acrylate described in Comparative Example 1 and Example 1 is that the catalyst used in the fluorination reaction process is different.
[0102] In the synthesis process of 2-fluoroalkyl acrylate described in Comparative Example 1, the catalyst used in the fluorination reaction process is acetic acid. The yield of methyl 2,3-difluoropropionate is 45%.
[0103] Comparative Example 2
[0104] The synthesis process of a 2-fluoroalkyl acrylate described in Comparative Example 2 is different from that in Example 1 only in that a different basic compound is used.
[0105] In the synthesis process of 2-fluoroalkyl acrylate described in Comparative Example 2, the alkaline compound used is sodium hydroxide, and the yield of methyl 2-fluoroacrylate is only 43%, and a large amount of methyl 2-fluoroacrylate is hydrolyzed to generate sodium 2-fluoroacrylate and methanol.
[0106] Comparative Example 3
[0107] The synthesis process of a 2-fluoroalkyl acrylate described in Comparative Example 3 is different from that in Example 1 only in that different fluorination agents are used in the fluorination process.
[0108] In the synthesis process of 2-fluoroalkyl acrylate described in Comparative Example 3, sulfur tetrafluoride is used as the fluorination agent, and the yield of methyl 2,3-difluoropropionate is 52%.
[0109] Although the above embodiments have been shown and described, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations on the present invention. Changes, modifications, substitutions and variations of the above embodiments by those of ordinary skill in the art are all within the scope of protection of the present invention.
Claims
1. A process for synthesizing 2-fluoroalkyl acrylate, characterized in that: The following steps are involved: (1) contacting an alkyl epoxypropionate with a fluorinating agent to carry out a fluorination reaction to obtain an alkyl 2,3-difluoropropionate; (2) Releasing 2,3-difluoropropionic acid alkyl ester with a basic compound to obtain 2-fluoroacrylate alkyl ester.
2. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: In step (1), the structural formula of the alkyl epoxypropionate is as shown below: wherein R is a C1-C8 straight or branched alkyl group, a C6-C8 aryl group, or a C3-C8 cycloalkyl group which is substituted or unsubstituted with a heteroatom; preferably, the heteroatom substituent includes one or more of a halogen, an oxygen atom, a nitrogen atom, and a sulfur atom; Preferably, R comprises one or more of methyl, ethyl, propyl, butyl, cyclohexyl, phenyl, benzyl, phenethyl, difluoroethyl, trifluoroethyl, 2,2,3,3,4,4,5,5-octafluoropentyl, 4-chlorophenyl, 3-oxabutyl, 3,6-dioxaheptyl and N,N-dimethylaminoethyl.
3. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: The fluorination agent includes one or more of N,N-dimethyl-1,1,2,2-tetrafluoroethylamine, N,N-dimethyl-1,1,2,3,3,3-hexafluoropropylamine and N,N-dimethyl-1,1,2-trifluoro-2-chloroethylamine, N,N-diethyl-1,1,2,2-tetrafluoroethylamine, N,N-diethyl-1,1,2,3,3,3-hexafluoropropylamine and N,N-diethyl-1,1,2-trifluoro-2-chloroethylamine.
4. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: The fluorination reaction is carried out in the presence of a catalyst, and the catalyst includes a protonic acid and / or a Lewis acid; Preferably, the catalyst comprises one or more of boron trifluoride, hydrogen fluoride, antimony trifluoride, antimony pentafluoride, antimony pentachloride, titanium tetrafluoride, aluminum trichloride and zinc fluoride; And / or, the fluorination reaction is carried out in the presence of a first solvent or in the absence of a solvent; preferably, the first solvent includes an amide solvent, an ether solvent or a nitrile solvent; more preferably, the first solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, methyltetrahydrofuran, acetonitrile, benzonitrile and diethyl ether.
5. The synthesis process of 2-fluoroalkyl acrylate according to claim 4, characterized in that: The molar ratio of the alkyl epoxypropionate to the fluorination agent is 1:(0.9-2); and / or, the mass ratio of the alkyl glycidyl ester to the catalyst is 1:(0.05-0.3); And / or, the mass ratio of the alkyl epoxypropionate to the first solvent is 1:(0-5).
6. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: The temperature of the fluorination reaction is 20-120° C., and the time of the fluorination reaction is 2-22 hours.
7. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: In step (2), the basic compound includes an inorganic base, an organic base or an alkali metal alkoxide corresponding to the alkyl group in the alkyl epoxypropionate; Preferably, the inorganic base comprises potassium carbonate and / or sodium carbonate; the organic base comprises one or more of triethylamine, tetramethylethylenediamine, 1,8-diazabicyclo[5,4,0]-7-undecene, 1,5-diazabicyclo[4.3.0]-5-nonene, dimethylcyclohexylamine and pyridine; the alkali metal alkali salt comprises one or more of sodium methoxide, potassium methoxide, sodium trifluoroethoxide, potassium ethoxide and sodium ethoxide.
8. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: The 2,3-difluoropropionic acid alkyl ester and the basic compound are mixed in a second solvent; Preferably, the second solvent comprises an aprotic solvent; more preferably, the aprotic solvent comprises one or more of an amide solvent, a sulfone solvent, a sulfoxide solvent, an ether solvent and a nitrile solvent; Preferably, the second solvent includes one or more of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, cyclopentane, N-methylpyrrolidone, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, tetrahydrofuran, methyltetrahydrofuran, methyl tert-butyl ether, acetonitrile and benzonitrile.
9. The synthesis process of 2-fluoroalkyl acrylate according to claim 8, characterized in that: The molar ratio of the 2,3-difluoropropionic acid alkyl ester to the basic compound is 1:(1-2); And / or, the mass ratio of the 2,3-difluoropropionic acid alkyl ester to the second solvent is 1:(2-20).
10. The synthesis process of 2-fluoroalkyl acrylate according to claim 1, characterized in that: In step (2), the reaction temperature is 50-100° C. and the reaction time is 2-8 h; And / or, the absolute pressure of the reaction is 5 kPa-100 kPa; And / or, the synthesis process further comprises extracting 2-fluoroacrylate alkyl ester from the reaction product of 2,3-difluoropropionic acid alkyl ester and the alkaline compound, and the extraction method comprises reactive distillation coupling or distillation separation.