A method for preparing ethyl trifluoroacetate

Abstract

The application relates to the technical field of organic synthesis, in particular to a preparation method of ethyl trifluoroacetate, which comprises the following steps: S1, 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether is added into a reaction kettle, concentrated sulfuric acid is added dropwise under stirring at a certain reaction temperature, after the dropwise addition is completed, the reaction is continuously kept for reaction completion, and a compound shown in formula I is obtained; S2, water is added into a reaction container, the compound shown in formula I prepared in the step S1 is added dropwise into the reaction container for hydrolysis reaction at a certain temperature, after the reaction is completed, the reaction is allowed to stand and is separated into layers, and the lower organic layer is ethyl trifluoroacetate; the reaction involved in the application is a reaction under low temperature and normal pressure, the equipment used in the reaction is a conventional general equipment, the method is simple and easy to operate, and is suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically a method for preparing ethyl trifluoroacetate. Background Technology

[0002] Ethyl trifluoroacetate, CAS No.: 383-63-1, boiling point: 61.7℃, volatile, colorless, transparent liquid with an ester-like odor.

[0003] Ethyl trifluoroacetate, as an important organic chemical raw material, has wide applications in the synthesis of organofluorine compounds, pharmaceuticals, pesticides, liquid crystals, and dyes. In pharmaceuticals, it is mainly used to produce anti-inflammatory drugs for osteoarthritis, antitumor drugs for treating colon and rectal cancer, and cardiovascular drugs such as lenopril. In pesticides, it is mainly used to manufacture cell division inhibitors, applied to control grasses and broadleaf weeds in cotton and peanut fields. In organic synthesis, due to its low removal rate under mild conditions, ethyl trifluoroacetate is often used for the protection of amino groups.

[0004] The traditional method for preparing ethyl trifluoroacetate involves using trifluoroacetic acid as a raw material and reacting it with ethanol under the catalysis of concentrated sulfuric acid or solid acid. The main drawbacks of this method are low single-pass conversion rate and equipment corrosion. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing ethyl trifluoroacetate, which overcomes at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing ethyl trifluoroacetate, the method comprising the following steps:

[0008] S1. 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether was added to a reaction vessel. Concentrated sulfuric acid was added dropwise while stirring at a certain reaction temperature. After the addition was completed, the reaction was kept at the temperature until the reaction was complete, and the compound shown in Formula I was obtained.

[0009] In step S2, water is added to the reaction vessel, and the compound of formula I obtained in step S1 is added dropwise to the reaction vessel at a certain temperature to carry out the hydrolysis reaction. After the reaction is completed, the mixture is allowed to stand and separate into layers. The lower organic layer is ethyl trifluoroacetate.

[0010] Furthermore, in step S1, the reaction temperature is controlled at 10-100°C when adding concentrated sulfuric acid, and the concentration of concentrated sulfuric acid is 90%-98%. After the addition of concentrated sulfuric acid is completed, the reaction temperature is controlled at 30°C to continue the reaction.

[0011] Furthermore, in step S1, the reaction temperature is controlled at 20–60°C and the concentration of concentrated sulfuric acid is 90%–96% when concentrated sulfuric acid is added dropwise.

[0012] Furthermore, the molar ratio of the 2,2,2-trifluoro-1,1-dichloroethyl ether to 95% concentrated sulfuric acid is 1:1 to 2.

[0013] Furthermore, the molar ratio of the 2,2,2-trifluoro-1,1-dichloroethyl ether to 95% concentrated sulfuric acid is 1:1.5.

[0014] Furthermore, the hydrolysis reaction in step S2 is carried out at a temperature of less than 30°C.

[0015] The beneficial effects of adopting the technical solution of the present invention are:

[0016] The reaction involved in this invention is carried out at a relatively low temperature and normal pressure. The equipment used in the reaction is conventional and easy to operate, making it suitable for industrial production.

[0017] The raw materials used in this invention are all conventional and have no special requirements; no additional catalyst is added during the reaction, and the reaction status can be monitored at any time, so that the reaction can be carried out in one go and completely avoid secondary recycling and processing, thus reducing the loss of raw materials. Attached Figure Description

[0018] Figure 1 This is the mass spectrum of the ethyl trifluoroacetate compound prepared in this invention.

[0019] Figure 2 The image shows the gas chromatogram of the ethyl trifluoroacetate compound prepared in Example 1. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to specific examples. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Raw material source: 99.5% 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether (Ningbo Yinuo Chemicals Co., Ltd., Mengcheng Technology (Shanghai) Co., Ltd.)

[0022] A method for preparing ethyl trifluoroacetate, the method comprising the following steps:

[0023] S1. 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether was added to a reaction vessel. Concentrated sulfuric acid was added dropwise while stirring at a certain reaction temperature. After the addition was completed, the reaction was kept at the temperature until the reaction was complete, and the compound shown in Formula I was obtained.

[0024] In step S2, water is added to the reaction vessel, and the compound of formula I obtained in step S1 is added dropwise to the reaction vessel at a certain temperature to carry out the hydrolysis reaction. After the reaction is completed, the mixture is allowed to stand and separate into layers. The lower organic layer is ethyl trifluoroacetate.

[0025] The reaction principle of this invention is as follows:

[0026]

[0027] Reaction formula (1) reveals the reaction principle by which sulfuric acid participates in the reaction to generate sulfuric acid ester compounds.

[0028]

[0029]

[0030] Reaction formulas (2) and (3) reveal the process by which the sulfate ester compound generated in reaction formula (1) reacts with water to produce ethyl trifluoroacetate.

[0031] The three reaction equations above fully illustrate the principle that 2,2,2-trifluoro-1,1-dichloroethyl ether reacts with concentrated sulfuric acid to produce the corresponding sulfate ester compound, and the sulfate ester compound is added to water and further reacts to produce ester compounds. This provides a theoretical basis for improving the production efficiency of this reaction.

[0032] Figure 1 This is the mass spectrum of the ethyl trifluoroacetate compound prepared in this invention.

[0033] Figure 2 The image shows the gas chromatogram of the ethyl trifluoroacetate compound prepared in Example 1.

[0034] Example 1

[0035] 197 g of 2,2,2-trifluoro-1,1-dichloroethyl ether was added to a 1-liter carbon steel stirred reactor. While stirring, 155 g of 95% concentrated sulfuric acid was added dropwise, maintaining the reaction temperature below 50°C. After the addition was complete, the temperature was maintained at approximately 30°C, and the reaction was stirred for 4 hours to obtain the sulfate ester product with a yield of 99%. During the reaction, the exhaust gas was absorbed with water.

[0036] Add 350 g of water to a 1-liter four-necked glass flask equipped with a stirrer. Add the sulfated ester compound obtained from the reaction dropwise into the flask, maintaining the reaction temperature below 30°C using a water bath. After the addition is complete, allow the mixture to stand and separate into layers. The lower layer, containing 138 g of organic matter, has a trifluoroethyl acetate content of 98.3%.

[0037] Example 2

[0038] 300 g of 2,2,2-trifluoro-1,1-dichloroethyl ether was added to a 1-liter carbon steel stirred reactor. While stirring, 305 g of 98% concentrated sulfuric acid was added dropwise, maintaining the reaction temperature below 60°C. After the addition was complete, the temperature was maintained at approximately 30°C, and the reaction was stirred for 4 hours to obtain the sulfate ester product with a yield of 99%. During the reaction, the exhaust gas was absorbed with water.

[0039] 600 g of water was added to a 1-liter four-necked glass flask equipped with a stirrer. The sulfate ester compound obtained from the reaction was then added dropwise into the flask, and the reaction temperature was controlled below 30°C using a water bath. After the addition was complete, the mixture was allowed to stand and separate into layers. 208 g of the lower layer of organic matter was separated, containing 98.5% ethyl trifluoroacetate.

[0040] Example 3

[0041] 500 g of 2,2,2-trifluoro-1,1-dichloroethyl ether was added to a 1-liter carbon steel stirred reactor. While stirring, 324 g of 92% concentrated sulfuric acid was added dropwise, maintaining the reaction temperature below 60°C. After the addition was complete, the temperature was maintained at approximately 30°C, and the reaction was stirred for 4 hours to obtain the sulfate ester product with a yield of 99%. During the reaction, the exhaust gas was absorbed with water.

[0042] 800 g of water was added to a 2-liter four-necked glass flask equipped with a stirrer. The sulfate ester compound obtained from the reaction was then added dropwise into the flask, and the reaction temperature was controlled below 30°C using a water bath. After the addition was complete, the mixture was allowed to stand and separate into layers. The lower layer of organic matter weighed 345 g and contained 98% ethyl trifluoroacetate.

[0043] Example 4

[0044] 2000 g of 2,2,2-trifluoro-1,1-dichloroethyl ether was added to a 5-liter stirred tank lined with PTFE and equipped with a stirrer. 507 g of 98% concentrated sulfuric acid was added dropwise while stirring, maintaining the reaction temperature below 60°C. After the addition was complete, the temperature was maintained at approximately 30°C and the reaction was stirred for 2 hours to obtain the sulfate ester product. The reaction apparatus was then converted to a distillation apparatus, and 183 g of water was added dropwise to the stirred tank while maintaining the temperature at 40°C. After the addition was complete, stirring was continued for 2 hours, followed by distillation. 1400 g of ethyl trifluoroacetate with a boiling point of 60–62°C and a purity of 98.8% was collected. The sulfuric acid in the stirred tank, after cooling, can be reused as a raw material for the production of sulfate ester compounds.

[0045] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent claim. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A process for the preparation of ethyl trifluoroacetate, characterized in that: The preparation method comprises the following steps: S1: 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether is added into a reaction kettle, concentrated sulfuric acid is added dropwise under stirring at a certain reaction temperature, after the dropwise addition is completed, the reaction is continued to be kept until the reaction is completed, and a compound shown in formula I is obtained; S2: water is added into a reaction container, the compound shown in formula I prepared in step S1 is added dropwise into the reaction container for hydrolysis reaction at a certain temperature, after the reaction is completed, the reaction is allowed to stand and is separated into layers, and the lower organic layer is ethyl trifluoroacetate.

2. A process for the preparation of ethyl trifluoroacetate according to claim 1, characterized in that: In the step S1, the reaction temperature is controlled to be 10-100 DEG C during the dropwise addition of the concentrated sulfuric acid, the concentration of the concentrated sulfuric acid is 90-98%, and the reaction temperature is controlled to be 30 DEG C after the dropwise addition of the concentrated sulfuric acid is completed.

3. A process for the preparation of ethyl trifluoroacetate according to claim 2, characterized in that: In the step S1, the reaction temperature is controlled to be 20-60 DEG C during the dropwise addition of the concentrated sulfuric acid, and the concentration of the concentrated sulfuric acid is 90-96%.

4. The process for the preparation of ethyl trifluoroacetate as claimed in claim 1, wherein: The molar ratio of the 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether to the 95% concentrated sulfuric acid is 1:1-2.

5. A process for the preparation of ethyl trifluoroacetate according to claim 4, characterized in that: The molar ratio of the 2,2,2-trifluoro-1,1-dichloroethyl ethyl ether to the 95% concentrated sulfuric acid is 1:1.

5.

6. The process for the preparation of ethyl trifluoroacetate as claimed in claim 1, wherein: In the step S2, the temperature of the hydrolysis reaction is less than 30 DEG C.

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