A preparation method of 1,1,1,4,4,4-hexafluoro-2-butanone

Abstract

The invention discloses a method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone, and belongs to the technical field of fluorine-containing fine chemicals. The method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone of the present invention uses 3-chloro-1,1,1-trifluoroacetone as a substrate, and reacts with trifluoromethane in a reaction solvent under the conditions of cuprous halide and tert-butanol alkali metal salt to generate 1,1,1,4,4,4-hexafluoro-2-butanone. Protonic acid and other corrosive and highly toxic reagents are not used, which solves the problem that the existing method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone is unfriendly to the environment. The raw material trifluoromethane is widely available, and the raw material is cheap and easy to obtain. In the presence of cuprous halide and tert-butanol alkali metal salt, 1,1,1,4,4,4-hexafluoro-2-butanone is prepared by a next step, and the reaction process is short and controllable, the reaction conditions are mild, the raw material conversion rate is high, and the product selectivity is high.

Description

Technical Field

[0001] The invention discloses a method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone, belonging to the technical field of fluorine-containing fine chemicals. Background Art

[0002] With the rapid development of high-speed rail, electric vehicles, big data algorithms, and new energy technologies, the technology and assembly of power electronic devices are showing a trend of high frequency, high power, and high integration. High-power power electronic components will generate a lot of heat when working, forming a very high heat flux density. In order to ensure the stable operation of the equipment, appropriate heat dissipation measures need to be taken to solve the problem of temperature rise inside the equipment. Due to the advantages of high cooling efficiency, low noise, compact cooling equipment structure, and long-distance heat transmission, the immersion liquid cooling system has been widely used in high-voltage power transmission and transformation, railway locomotive traction converters, electric vehicle motor controllers, and big data transmission. The development of electronic coolant is a necessary condition for realizing the high efficiency and large-scale of immersion liquid cooling technology, and is currently a hot topic in the research of liquid cooling technology.

[0003] The immersion coolant used in the prior art is perfluorinated compounds (PFCs), such as FC-72 (perfluorohexane), FC-770, FC-3283 (perfluorotripropylamine), FC-43 (perfluorotributylamine), etc. Perfluorinated compounds have the advantages of high dielectric strength, good chemical inertness and thermal stability, non-flammability, non-toxicity and harmlessness to humans, and good material compatibility, and are ideal coolants for immersion liquid cooling. However, since the GWP (global warming potential) of perfluorinated compounds is greater than 5000, it is one of the six greenhouse gases of concern in the Kyoto Protocol, so it is necessary to develop a new type of electronic coolant molecule that meets the requirements for electrical and thermal conductivity and has a low greenhouse potential.

[0004] 1,1,1,4,4,4-hexafluoro-2-butanone has a boiling point of 54°C, and its electrical conductivity and thermal conductivity are close to those of currently used electronic coolants, making it an ideal new type of electronic coolant molecule. Chambers et al. (J. Fluorine Chem. 1984, 25, 47) reported in 1984 a method for preparing hexafluorobutanone by thermal hydrolysis of hexafluorobutyne. However, since hexafluorobutyne is expensive and a toxic gas, it is not economical. Yamakawa et al. (J. Fluorine Chem. 2016, 181, 1-6) reported a method for preparing hexafluorobutanone using trifluoroiodomethane as a raw material. However, due to the use of iodine-containing reagents, the preparation cost of this method is higher and there are more wastes. Chinese patent CN114409514 discloses a method in which 1,1,1,4,4,4-hexafluoro-2-chlorobutene reacts with an alkali metal hydroxide in an alcohol solvent at 40-80°C under the action of a phase transfer catalyst; after cooling to room temperature, a protonic acid is added for acidification reaction, and after filtering the reaction solution, 1,1,1,4,4,4-hexafluoro-2-butanone is obtained by distillation. This method has the disadvantages of high reaction pressure, and although the raw material 1,1,1,4,4,4-hexafluoro-2-chlorobutene is an intermediate for preparing HFO-1336mzz, there are very few HFO-1336mzz manufacturers, and there is a problem of a single limited source of raw materials. At the same time, since reagents such as protonic acids are used in the preparation process, it has the defects of strong corrosiveness and toxicity, and is not environmentally friendly.

[0005] Therefore, it is urgent to develop a method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone that can overcome the problems of expensive raw materials and high toxicity in the prior art 1,1,1,4,4,4-hexafluoro-2-butanone, mild reaction conditions and high safety. Summary of the invention

[0006] The invention aims to solve the problems of expensive raw materials and high toxicity in the prior art 1,1,1,4,4,4-hexafluoro-2-butanone preparation method, and provide a method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone by using 3-chloro-1,1,1-trifluoroacetone and trifluoromethane as main raw materials. The method has low raw material input cost, mild reaction conditions, high raw material conversion rate, mild reaction conditions and high safety.

[0007] In order to achieve the purpose of the invention, the technical solution adopted by the present invention is:

[0008] A method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone, using 3-chloro-1,1,1-trifluoroacetone as a substrate, reacting with trifluoromethane (R23) in a reaction solvent under the conditions of cuprous halide and tert-butoxide alkali metal salt to generate 1,1,1,4,4,4-hexafluoro-2-butanone. The synthesis route is as follows:

[0009] .

[0010] Preferably, the molar ratio of the 3-chloro-1,1,1-trifluoroacetone to the alkali metal salt of tert-butoxide and trifluoromethane is 1:1:3-5.

[0011] Preferably, the cuprous halide is cuprous chloride.

[0012] Preferably, the alkali metal salt of tert-butoxide is potassium tert-butoxide.

[0013] Preferably, the reaction solvent is any one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

[0014] Preferably, the molar ratio of the cuprous halide, alkali metal salt of tert-butoxide and reaction solvent is 1:5:5-10.

[0015] Preferably, the reaction time of the reaction is 14 to 18 hours.

[0016] Preferably, the reaction pressure of the reaction is 0 to 2.0 MPa.

[0017] Preferably, the reaction temperature of the reaction is 140-200°C.

[0018] Preferably, the reaction uses a high-pressure reactor as a reaction vessel.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The preparation method of 1,1,1,4,4,4-hexafluoro-2-butanone of the present invention uses trifluoromethane, a byproduct produced in the industrial production of difluoromonochloromethane, as a raw material, which has a wide source and is cheap and easy to obtain.

[0021] 2. The preparation method of 1,1,1,4,4,4-hexafluoro-2-butanone of the present invention is to prepare 1,1,1,4,4,4-hexafluoro-2-butanone in the presence of cuprous halide and tert-butoxide alkali metal salt in a one-step process, the reaction process is short and controllable, the reaction conditions are mild, the raw material conversion rate is high, and the product selectivity is high.

[0022] 3. The preparation method of 1,1,1,4,4,4-hexafluoro-2-butanone of the present invention does not use corrosive and toxic reagents such as protonic acid, thereby solving the problem that the existing preparation method of 1,1,1,4,4,4-hexafluoro-2-butanone is environmentally unfriendly. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the examples, which are used to illustrate the present invention but are not intended to limit the scope of protection of the present invention. The conditions in the examples can be further adjusted according to specific conditions, and simple improvements to the method of the present invention under the premise of the concept of the present invention all belong to the scope of protection claimed in the present invention.

[0024] Example 1

[0025] Cuprous chloride (9.9 g, 0.1 mol), potassium tert-butoxide (56.1 g, 0.5 mol), N, N-dimethylformamide (36.6 g, 0.5 mol) were added to a 1L stainless steel stirred autoclave, stirred at room temperature for 0.5 h, then trifluoromethane (105.0 g, 1.5 mol) was added, 3-chloro-1,1,1-trifluoroacetone (73.3 g, 0.5 mol) was added to the above reaction solution, the temperature was slowly raised to 140°C, the reaction was continued for 14 h, the reaction was cooled to room temperature, the unreacted trifluoromethane was collected, filtered, the filtrate was rectified, and the 51-53°C fraction was collected to obtain the finished product of 1,1,1,4,4,4-hexafluoro-2-butanone. The yield was calculated using 3-chloro-1,1,1-trifluoroacetone as the substrate.

[0026] Embodiments 2 to 4

[0027] The difference between Examples 2 to 4 and Example 1 is that the solvent is changed, and the reaction parameters and reaction results are shown in Table 1.

[0028] Table 1 Reaction parameters and results of Examples 1 to 4

[0029] Solvents Yield, % Example 1 N,N-Dimethylformamide 82.3 Example 2 N,N-Dimethylacetamide 84.3 Example 3 N-Methylpyrrolidone 85.1 Example 4 Dimethyl sulfoxide 84.9

[0030] Embodiment 5-6

[0031] The difference between Examples 5 and 6 and Example 1 is that the effect of the molar ratio of trifluoromethane to 3-chloro-1,1,1-trifluoroacetone on the reaction results is shown in Table 2.

[0032] Table 2 Reaction parameters and results of Examples 5 to 6

[0033] Molar ratio of trifluoromethane to 3-chloro-1,1,1-trifluoroacetone Yield, % Example 1 3:1 82.3 Example 5 4:1 85.2 Example 6 5:1 85.9

[0034] Embodiments 7 to 9

[0035] The difference between Examples 7 to 9 and Example 1 is that the effect of the amount of solvent on the reaction results is shown in Table 3.

[0036] Table 3 Reaction parameters and results of Examples 7 to 9

[0037] N,N-dimethylformamide solvent amount / mol Yield, % Example 1 0.5 82.3 Example 7 0.7 84.1 Example 8 0.9 83.7 Example 9 1.0 81.2

[0038] Embodiments 10 to 11

[0039] The difference between Examples 10 to 11 and Example 1 is that the effect of reaction time on reaction results is shown in Table 4.

[0040] Table 4 Reaction parameters and results of Examples 10 to 11

[0041] Reaction time Yield, % Example 1 14 82.3 Example 10 16 84.5 Embodiment 11 18 83.9

[0042] Embodiments 12 to 14

[0043] The difference between Examples 12 to 14 and Example 1 is that the effect of reaction temperature on the reaction results is shown in Table 5.

[0044] Table 5 Reaction parameters and results of Examples 12 to 14

[0045] Reaction temperature / ℃ Yield, % Example 1 140 82.3 Example 12 160 84.7 Embodiment 13 180 79.1 Embodiment 14 200 76.2

[0046] In summary, through the specific implementation data of the above embodiments, the preparation method of 1,1,1,4,4,4-hexafluoro-2-butanone of the present invention has mild reaction conditions, a yield higher than 76%, and high product selectivity.

[0047] The specific embodiments listed above are illustrations of the present invention. It should be pointed out that the above embodiments are only used to further illustrate the present invention and do not represent the scope of protection of the present invention. Non-essential modifications and adjustments made by others based on the suggestions of the present invention still fall within the scope of protection of the present invention.

Claims

1. A method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone, characterized in that: 3-Chloro-1,1,1-trifluoroacetone is used as a substrate, and reacts with trifluoromethane in a reaction solvent under the conditions of cuprous halide and tert-butoxide alkali metal salt to generate 1,1,1,4,4,4-hexafluoro-2-butanone; the synthesis route is as follows: ； The molar ratio of 3-chloro-1,1,1-trifluoroacetone to alkali metal salt of tert-butoxide and trifluoromethane is 1:1:3-5; The cuprous halide is cuprous chloride; The alkali metal salt of tert-butoxide is potassium tert-butoxide; The reaction pressure of the reaction is 0 to 2.0 MPa; The reaction temperature of the reaction is 140-200°C; The molar ratio of the cuprous halide, tert-butoxide alkali metal salt and reaction solvent is 1: 5: 5-10; The reaction time of the reaction is 14 to 18 hours.

2. A method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone as claimed in claim 1, characterized in that: The reaction solvent is any one of N-methylpyrrolidone, N,N-dimethylformamide, N,N-dimethylacetamide and dimethyl sulfoxide.

3. A method for preparing 1,1,1,4,4,4-hexafluoro-2-butanone as claimed in claim 1, characterized in that: To a 1L stainless steel stirred autoclave, add 9.9g of cuprous chloride, 56.1g of potassium tert-butoxide, and 36.6g of N,N-dimethylformamide, and stir at room temperature for 0.5h. Then charge 105.0g of trifluoromethane, add 73.3g of 3-chloro-1,1,1-trifluoroacetone to the above reaction solution, slowly heat to 140°C, react for 14h, cool to room temperature, collect unreacted trifluoromethane, filter, distill the filtrate, collect the 51-53°C fraction, and obtain 1,1,1,4,4,4-hexafluoro-2-butanone.

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