Method for producing trifluoroacetic acid ester

Abstract

The present invention relates to a method for producing trifluoroacetic acid, whereby trifluoroacetic acid can be purified by a simple method such as distillation without using an amine or potassium fluoride. Also provided is a method for producing a trifluoroacetic acid ester, the method comprising a reaction step for obtaining a trifluoroacetic acid ester and HF by adding equal moles or more of CF3COF to a lower alcohol having 1-4 carbon atoms.

Description

Technical Field

[0001] The present invention relates to a method for producing trifluoroacetate. Background Art

[0002] Trifluoroacetate has long been used as a raw material for pharmaceuticals and pesticides, and its importance is expected to increase in the future.

[0003] As a method for producing trifluoroacetate, there are known methods of reacting CF3COF with ethanol in the presence of potassium fluoride, as disclosed in Patent Documents 1 and 2. In addition, there is also known a method of using amines instead of the above-mentioned potassium fluoride, as disclosed in Patent Document 3.

[0004] Prior art literature Patent Literature Patent Document 1: China Invention Patent Application Publication No. CN104402714 Patent Document 2: China Invention Patent Application Publication No. CN104370730 Patent Document 3: China Invention Patent Application Publication No. CN102351694 Summary of the Invention

[0005] Problems to be solved by the invention In view of the above circumstances, an object of the present invention is to find a method for producing trifluoroacetic acid which does not use amines or potassium fluoride and can purify trifluoroacetic acid by a simple method such as distillation.

[0006] Technical solutions to problems The inventors of the present invention conducted extensive research to address the above-mentioned issues and discovered that trifluoroacetic acid esters can be obtained by adding an excess of CF3COF to a lower alcohol having 1 to 4 carbon atoms, without using additives such as amines or potassium fluoride, and by simply distilling the reaction product. Based on this knowledge, the inventors of the present invention conducted further research and completed the present invention.

[0007] That is, the present invention relates to a method for producing the following trifluoroacetate.

[0008] Item 1 A method for producing trifluoroacetate, wherein the method for producing trifluoroacetate comprises a reaction step of adding equimolar or more CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF.

[0009] Item 2 The production method according to item 1, wherein in the reaction step, CF3COF is added at a molar ratio of 1 to 3 mol per 1 mol of the lower alcohol having 1 to 4 carbon atoms.

[0010] Item 3 The production method according to item 1 or 2, wherein the lower alcohol having 1 to 4 carbon atoms is ethanol.

[0011] Item 4 A composition comprising trifluoroacetate, HF and CF3COF, wherein the content of CF3COF is 0.1 to 30% by mass.

[0012] Effects of the Invention According to the method for producing trifluoroacetic acid ester of the present invention as described above, trifluoroacetic acid can be purified by a simple operation such as distilling the reaction product without using amines or potassium fluoride. DETAILED DESCRIPTION

[0013] In this specification, the term "comprising" is a concept encompassing any of "including," "consisting essentially of," and "consisting only of." Furthermore, in this specification, when a numerical range is expressed as "A to B," it means greater than or equal to A and less than or equal to B.

[0014] The method for producing trifluoroacetate of the present invention comprises a reaction step of adding equimolar or more CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF.

[0015] The lower alcohol having 1 to 4 carbon atoms is not particularly limited, and a wide range of known compounds can be used. However, ethanol is preferably used because it is particularly effective in producing ethyl trifluoroacetate as the target compound.

[0016] CF3COF is added in an equimolar ratio or greater with respect to the lower alcohol having 1 to 4 carbon atoms, that is, at a ratio of 1 mole or greater per 1 mole of the lower alcohol having 1 to 4 carbon atoms. If CF3COF is not added in an equimolar ratio or greater with respect to the lower alcohol having 1 to 4 carbon atoms, the reaction product will contain the lower alcohol having 1 to 4 carbon atoms, and the purification process of the final target product, trifluoroacetate, cannot be simplified. If the product forms an azeotropic composition such as a lower alcohol having 1 to 4 carbon atoms / trifluoroacetate, water / trifluoroacetate / lower alcohol having 1 to 4 carbon atoms, or a lower alcohol having 1 to 4 carbon atoms / HF, separation of the trifluoroacetate becomes difficult.

[0017] As described above, CF3COF is preferably added at a ratio of 1 mol or more per mol of the lower alcohol having 1 to 4 carbon atoms, more preferably at a ratio exceeding 1 mol, further preferably at a ratio of 1.02 mol or more, and even more preferably at a ratio of 1.05 mol or more. The upper limit of the amount of CF3COF added is preferably 3 mol, more preferably 1.5 mol, and even more preferably 1.2 mol per mol of the lower alcohol having 1 to 4 carbon atoms, to avoid recovery loss of the raw material CF3COF.

[0018] In the reaction process of adding CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF, in order to suppress the dissolution of CF3COF in the crude reaction product and avoid excessive reuse in the distillation process, the temperature condition is preferably set to above -20°C, more preferably above 0°C, and even more preferably above 10°C.

[0019] Furthermore, in the reaction step of adding CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF, in order to suppress corrosion of the reaction equipment and not increase the reaction pressure, the temperature condition is preferably set to below 100°C, more preferably below 95°C, and even more preferably below 90°C.

[0020] To minimize the loss of reaction products and raw materials, the reaction step in which CF3COF is added to a lower alcohol having 1 to 4 carbon atoms to produce trifluoroacetate and HF is preferably conducted under sealed conditions. In this case, the addition of nitrogen or argon, etc., can result in a low CF3COF recovery rate and is therefore preferably omitted. The reaction pressure may be either reduced or increased depending on the reaction temperature, but is preferably -0.05 MPaG or higher, more preferably 0.0 MPaG or higher, and even more preferably 0.1 MPaG or higher, for the purpose of accelerating the reaction rate.

[0021] For the purpose of leakage prevention (safety), the reaction pressure in the reaction step of adding CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF is preferably 1.5 MPaG or less, more preferably 1.0 MPaG or less, and even more preferably 0.8 MPaG or less.

[0022] In order to maintain a stable temperature (gradual heating), the reaction time in the reaction step of adding CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF is preferably 1 hour or more, more preferably 2 hours or more, and even more preferably 3 hours or more.

[0023] In order to improve productivity, the reaction time in the reaction step of adding CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF is preferably 24 hours or less, more preferably 20 hours or less, and further preferably 16 hours or less.

[0024] The reaction product obtained by adding an equal mole or more of CF3COF to a lower alcohol having 1 to 4 carbon atoms is subjected to a purification step to obtain high-purity trifluoroacetate.

[0025] The purification method in the purification step is not particularly limited, and a wide range of known purification methods can be employed. However, purification by distillation is preferred due to its simplicity.

[0026] The invention discloses a composition containing trifluoroacetate, HF and CF3COF, wherein the CF3COF content is 0.1 to 30% by mass.

[0027] The content of CF3COF contained in the composition of the present invention is 0.1% by mass or more, preferably 0.2% by mass or more, and more preferably 0.5% by mass or more in 100% by mass of the composition of the present invention.

[0028] On the other hand, the content of CF3COF contained in the composition of the present invention is 30% by mass or less, preferably 10% by mass or less, and more preferably 5% by mass or less in 100% by mass of the composition of the present invention.

[0029] The content of trifluoroacetate in 100% by mass of the composition of the present invention is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more.

[0030] On the other hand, the content of trifluoroacetate in 100% by mass of the composition of the present invention is preferably 90% by mass or less, more preferably 89% by mass or less, and even more preferably 88% by mass or less.

[0031] The HF content in 100% by mass of the composition of the present invention is preferably 10% by mass or more, more preferably 11% by mass or more, and even more preferably 12% by mass or more.

[0032] On the other hand, the HF content in 100% by mass of the composition of the present invention is 15% by mass or less, more preferably 14% by mass or less, and even more preferably 13% by mass or less.

[0033] The composition of the present invention can be obtained by adding an equimolar amount or more of CF3COF to a lower alcohol having 1 to 4 carbon atoms.

[0034] The composition of the present invention may contain at least one selected from trifluoroacetic acid, toluene and water within a range not impairing the effects and purposes of the invention.

[0035] The above describes the embodiments of the present invention. Needless to say, the present invention is not limited by these embodiments and can be implemented in various ways without departing from the scope of the present invention.

[0036] Example Hereinafter, the embodiments of the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0037] (Example 1) A 1L stainless steel autoclave was charged with 204g / 4.43mol of ethanol (0.2% water content). While heating to 60°C and stirring, 585g / 5.04mol of CF3COF was added at a constant flow rate and allowed to react. The reaction pressure ultimately reached 0.6 MPaG. After the reaction, the reaction mixture was distilled in a distillation column at atmospheric pressure. The low-boiling-point CF3COF was recovered, and after extracting the HF fraction with a boiling point of 20°C, 580g of high-purity ethyl trifluoroacetate (92% yield) was recovered.

[0038] (Examples 2 to 6) As shown in Table 1 below, Examples 2 to 6 were carried out according to the method of Example 1.

[0039] [Table 1] (Comparative Example 1) A 1L stainless steel autoclave was charged with 204g / 4.435mol of ethanol (0.2% water content). Heated to 60°C and stirred, 250g / 2.16mol of CF3COF was added at a constant flow rate and allowed to react. The reaction pressure eventually reached atmospheric pressure. Following the reaction, the reaction mixture was distilled in a distillation column at atmospheric pressure. An azeotropic mixture of ethanol and ethyl trifluoroacetate was formed, which could not be separated by distillation, and ethyl trifluoroacetate was not obtained.

[0040] As shown in Table 2 below, according to each Example, the alcohol in the obtained composition was discharged, and according to Comparative Example 1, an azeotropic composition of ethanol and ethyl trifluoroacetate was formed as described above.

[0041] [Table 2]

Claims

1. A method for producing trifluoroacetate, characterized in that: The method for producing trifluoroacetate comprises a reaction step of adding equimolar or more CF3COF to a lower alcohol having 1 to 4 carbon atoms to obtain trifluoroacetate and HF.

2. The manufacturing method according to claim 1, wherein In the reaction step, CF3COF is added at a molar ratio of 1 to 3 mol relative to 1 mol of the lower alcohol having 1 to 4 carbon atoms.

3. The manufacturing method according to claim 1 or 2, wherein: The lower alcohol having 1 to 4 carbon atoms is ethanol.

4. A composition, characterized in that Contains trifluoroacetate, HF and CF3COF, and the content of CF3COF is 0.1 to 30% by mass.

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