Preparation method of (E)-1, 1, 1, 2, 2, 5, 5, 6, 6, 6-decafluorohexyl-3-ene

Abstract

The invention discloses a preparation method of (E)-1, 1, 1, 2, 2, 5, 5, 6, 6, 6-decafluorohexyl-3-ene, and the preparation method comprises the following steps: carrying out telomerization reaction on 1, 1-difluoroethane, tetrafluoroethylene and HF in the presence of a catalyst to prepare 1, 1, 1, 2, 2, 5, 5, 6, 6, 6-decafluorohexane, and then carrying out halogenation and dehydrohalogenation reaction to prepare (E)-1, 1, 1, 2, 2, 5, 5, 6, 6, 6-decafluorohexyl-3-ene. The preparation method provided by the invention has the advantages of cheap and easily available raw materials and high product selectivity.

Description

Technical Field

[0001] This application belongs to the field of organic synthesis, specifically relating to a method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene and its application. Background Technology

[0002] As a key material in liquid cooling technology, immersion coolant has attracted widespread attention since its introduction. In particular, with the successive introduction of perfluoroamines and perfluoropolyethers with low dielectric constants and good thermal conductivity as fluorinated electronic coolants by companies such as 3M in the United States and Solvay in Belgium, and their initial application in the market, research on immersion liquid cooling has become one of the focal points in the field of fluorochemistry.

[0003] Hydrofluoroolefins are an important class of fluorinated fluids. Compared to perfluoroamines and perfluoropolyethers, they possess good chemical stability and are further characterized by relative environmental friendliness and excellent heat transfer performance. (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexane-3-ene is a typical trans-hydrofluoroolefin with a low dielectric constant, allowing high-frequency electronic components and connectors to be immersed in the fluid without significant loss of signal integrity, making it suitable as a heat transfer medium for electronic devices. Currently, there are few publicly available reports on the synthesis methods of (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexane-3-ene. The main methods are as follows:

[0004] (1) First synthetic route (A): Patent WO2023164093A2 generates 3,3,3-trichloro-1,1,1,2,2-pentafluoropropane through chlorination of 1,1,1,2,2-pentafluoropropane, and then generates 3,4-dichloro-1,1,2,2,5,5,6,6,6-decafluoro-3-hexene through dechlorination in the presence of Ru / SiC catalyst. The target substance is then generated by hydrogenation and dechlorination of 3,4-dichloro-1,1,2,2,2,5,5,6,6,6-decafluoro-3-hexene. The overall yield of cis-trans isomers is 88.81%, and the selectivity of trans isomers is 86.15%.

[0005] (2) Second synthetic route (B): Patent WO2023164125A2 uses 3,3,4,4-tetrachloro-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene to undergo a hydrogenation-dechlorination reaction in the presence of Ir / C or Pd-Cu / C catalysts, generating carbon-carbon double bonds to obtain the target substance. The total yield of cis-trans isomers can reach up to 49.44%, but the selectivity of individual isomers has not been reported.

[0006] (3) Third synthetic route (C): Patent WO2023164093A2 describes the reduction and dehalogenation reaction of 3,3-dichloro-1,1,1,2,2-pentafluoropropane in dimethylformamide solution under the action of excess copper powder and catalytic amount of 2,2-bipyridine to obtain the target substance. The yield was not reported, and the selectivity of the trans isomer was 85%.

[0007] In the above synthetic routes for (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene, routes A and B suffer from high cis isomer byproduct content, while route C has a low yield. Furthermore, the raw materials used in these routes are not directly available, resulting in high acquisition costs. Summary of the Invention

[0008] The technical problem to be solved by this application is to overcome the shortcomings of the prior art and provide a method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene with high yield and high selectivity.

[0009] The objective of this invention is achieved through the following technical solution:

[0010] 1,1,1,2,2,5,5,6,6,6-decafluorohexane was prepared by telomerization of 1,1-difluoroethane, tetrafluoroethylene and HF under a catalyst, followed by halogenation and dehydrohalogenation reactions to prepare (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene.

[0011]

[0012] Figure (E) shows the synthetic route for 1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene.

[0013] The telomerization reaction in step (a) comprises reacting 1,1-difluoroethane with tetrafluoroethylene in the presence of a Lewis acid catalyst and anhydrous hydrofluoric acid to obtain 1,1,1,2,2,5,5,6,6,6-decafluorohexane.

[0014] Preferably, the Lewis catalyst is any one of aluminum trifluoride, aluminum fluorochloride, and zirconium fluorochloride; the reaction temperature is 0℃~100℃, and the reaction time is 1~24h; the molar ratio of 1,1-difluoroethane, tetrafluoroethylene, Lewis catalyst, and anhydrous hydrofluoric acid is preferably 1:(2~4):(0.01~0.2):(1~5).

[0015] More preferably, the molar ratio of 1,1-difluoroethane, tetrafluoroethylene, Lewis catalyst and anhydrous hydrofluoric acid is 1:(2.5-3):(0.05-0.1):(2-3).

[0016] The halogenation reaction in step (b) includes: thermal halogenation of 1,1,1,2,2,5,5,6,6,6-decafluorohexane with a halogen to generate 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane.

[0017] The halogen is either chlorine or bromine.

[0018] Preferably, the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane to halogen is 1:1 to 6, and the reaction temperature is 150℃ to 400℃.

[0019] More preferably, the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane to halogen is 1:1.5 to 2.5; and the reaction temperature is 270°C to 320°C.

[0020] The dehydrohalogenation reaction in step (c) includes the removal of one molecule of hydrogen halide from 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane in a protic solvent under the action of a strong base and a phase transfer catalyst to obtain (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene.

[0021] The strong base is any one of potassium hydroxide, sodium hydroxide, sodium carbonate, and potassium carbonate, and the protic solvent is any one or a combination of water, methanol, ethanol, or isopropanol.

[0022] The preferred molar ratio of the 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane and the strong base is 1:1 to 2.

[0023] Further preferably, the molar ratio of 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane to the strong base is 1:1.4 to 1.6.

[0024] Preferably, the reaction temperature is 0℃~50℃ and the reaction time is 0.5~2h.

[0025] More preferably, the reaction temperature is 20℃~30℃ and the reaction time is 1h.

[0026] The present invention also provides an application of the compound prepared by the above-described preparation method, wherein the compound can be used as a working fluid in phase change immersion cooling systems in fields such as data centers, semiconductors, electronics, automobiles, and home appliances.

[0027] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0028] 1. The raw materials used in this invention are cheap and readily available, and there are bulk commodity processes available. At the same time, the process is simple, the conditions are mild, and it is suitable for industrial production.

[0029] 2. The trans isomer content of 1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene obtained by the present invention can be as high as 99.5% or more. Detailed Implementation

[0030] The present invention will be further described below with reference to specific embodiments, but the invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all alternatives, improvements, and equivalents that may be included within the scope of the claims.

[0031] In this embodiment of the invention, the reaction products are tested using gas chromatography. The analytical steps include: the reaction products are collected by condensation, and the condensate is subjected to gas chromatography analysis. High-purity nitrogen is used as the carrier gas. The detection conditions are: vaporization chamber temperature 220°C, detector temperature 250°C, initial column temperature 40°C, held for 10 min, heating rate 20°C / min, final temperature 220°C, held for 10 min.

[0032] Preparation Example 1

[0033] Anhydrous aluminum chloride (20 g, 0.09 mol) was added to a 250 ml reactor, which was then sealed. The reactor was purged with nitrogen three times and pressurized with nitrogen for 30 min to confirm good airtightness. Subsequently, dichlorofluoromethane (37.11 g, 0.43 mol) was added, and the reaction was carried out at room temperature for 3 h. After standing, the reactor was opened. The reaction mixture was filtered to remove the reaction solution, yielding 18.92 g of fluoroaluminum chloride catalyst, which was then stored in a desiccator for later use.

[0034] Preparation Example 2

[0035] The procedure in this preparation example is the same as in Preparation Example 1, except that anhydrous zirconium chloride (20 g, 0.15 mol) was used instead of anhydrous aluminum chloride to obtain 17.24 g of zirconium fluoride catalyst, which was then placed in a desiccator for later use.

[0036] Example 1

[0037] Aluminum fluorochloride catalyst (2.00 g) was added to a 500 ml reactor, which was then sealed. The reactor was purged with nitrogen three times and pressurized for 30 min to confirm good airtightness. The reactor was placed in a -40°C cryogenic bath, and 1,1-difluoroethane (15.00 g, 0.2271 mol), anhydrous hydrogen fluoride (40.00 g, 1.999 mol), and tetrafluoroethylene (50.00 g, 0.4999 mol) were added sequentially. The reaction was stirred at 20°C for 8 hours. After settling, the reactor was opened. The catalyst was removed by filtration. The organic phase was washed with aqueous sodium hydroxide solution, aqueous sodium bicarbonate solution, and water, respectively, dried with MgSO4, and distilled to obtain a 48.02 g fraction with a boiling point of 52°C, yielding 79.43%. Gas chromatography analysis showed that the target substance, 1,1,1,2,2,5,5,6,6,6-decafluorohexane, contained 97.63%.

[0038] Example 2

[0039] The operation in this embodiment is the same as in Example 1, except that zirconium fluorochloride is used instead of aluminum fluorochloride as the catalyst, while the amount remains the same, and other conditions remain unchanged. 29.51 g of the target product was obtained, with a yield of 48.84%. Gas chromatography analysis showed that the content of the target substance 1,1,1,2,2,5,5,6,6,6-decafluorohexane was 97.72%.

[0040] Example 3

[0041] The operation in this embodiment is the same as in Example 1, except that aluminum chloride is used instead of aluminum fluorochloride as the catalyst, while the amount remains the same, and other conditions remain unchanged. 25.72 g of the target product was obtained, with a yield of 42.57%. Gas chromatography analysis showed that the content of the target substance 1,1,1,2,2,5,5,6,6,6-decafluorohexane was 97.49%.

[0042] Example 4

[0043] 20 ml of activated carbon was packed into a Monel alloy tubular reactor with an inner diameter of 1 / 2 inch and a length of 40 cm. The reactor was heated to 300 °C, and the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane and chlorine was controlled at 1:3. The liquid raw material mixture was introduced into the mixing chamber using a sample pump. The liquid raw material was vaporized in the mixing chamber and passed through the reactor containing the catalyst for 10 seconds. The reaction product was collected in a cold trap after cooling. The composition of the reaction product was analyzed by gas chromatography. The conversion rate of the raw material 1,1,1,2,2,5,5,6,6,6-decafluorohexane was 97.26%, and the selectivity of the product 3-chloro-1,1,1,2,2,5,5,6,6,6-decafluorohexane was 89.91%. The results are shown in Table 1.

[0044] Example 5

[0045] The operation in this embodiment is the same as in embodiment 4, except that the reaction temperature is reduced to 250°C. The results are shown in Table 1.

[0046] Example 6

[0047] The operation in this embodiment is the same as in embodiment 4, except that the reaction temperature is reduced to 350°C. The results are shown in Table 1.

[0048] Example 7

[0049] The operation of this embodiment is the same as that of embodiment 4, except that the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane and chlorine is controlled to be 1:1.5. The results are shown in Table 1.

[0050] Example 8

[0051] The operation in this embodiment is the same as in embodiment 4, except that the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane and chlorine is controlled to be 1:2.5. The results are shown in Table 1.

[0052] Example 9

[0053] The operation in this embodiment is the same as in embodiment 4, except that the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane and chlorine is controlled to be 1:3. The results are shown in Table 1.

[0054] Example 10

[0055] The operation of this embodiment is the same as that of embodiment 8, except that the reaction contact time is increased to 15 seconds. The results are shown in Table 1.

[0056] Example 11

[0057] The operation of this embodiment is the same as that of embodiment 8, except that the reaction contact time is reduced to 8 seconds. The results are shown in Table 1.

[0058] Example 12

[0059] The operation of this embodiment is the same as that of embodiment 8, except that bromine is used instead of chlorine, the amount remains the same, and other conditions remain unchanged.

[0060] Table 1. Reaction Results

[0061]

[0062]

[0063] Example 13

[0064] A 500 ml three-necked flask equipped with a reflux condenser was placed in an ice-water bath. 150 ml of methanol and 50 g of potassium hydroxide were added, and the mixture was stirred until homogeneous. Then, 200 g (0.40 mol) of 3-chloro-1,1,1,2,2,5,5,6,6,6-decafluorohexane was slowly added dropwise through a constant-pressure dropping funnel, and the reaction was allowed to proceed for 2 hours at room temperature. The mixture was filtered to remove insoluble matter, and then separated using a separatory funnel. The lower liquid was washed three times with water, dried over MgSO4, and distilled to obtain a fraction of 178.59 g with a boiling point of 49 °C, yielding 90.58%. Gas chromatography analysis showed that the target substance (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene comprised 99.72% of the product.

[0065] Example 14

[0066] A 500 ml three-necked flask equipped with a reflux condenser was placed in an ice-water bath. 150 ml of methanol and 50 g of potassium hydroxide were added, and the mixture was stirred until homogeneous. Then, 200 g (0.37 mol) of 3-bromo-1,1,1,2,2,5,5,6,6,6-decafluorohexane was slowly added dropwise through a constant-pressure dropping funnel, and the reaction was allowed to proceed for 2 hours at room temperature. The mixture was filtered to remove insoluble matter, and then separated using a separatory funnel. The lower liquid was washed three times with water, dried over MgSO4, and distilled to obtain a fraction of 157.94 g with a boiling point of 49 °C, yielding 92.98%. Gas chromatography analysis showed that the target substance (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene comprised 99.78% of the product.

[0067] Comparative Example 1

[0068] Potassium fluoride (2.00 g) was added to a 500 ml reaction vessel, which was then sealed. The vessel was purged with gas three times, and pressurized with nitrogen for 30 min to confirm good airtightness. The reaction vessel was placed in a -40°C cryogenic bath, and 1,1-difluoroethane (15.00 g, 0.2271 mol), anhydrous hydrogen fluoride (40.00 g, 1.999 mol), and tetrafluoroethylene (50.00 g, 0.4999 mol) were added sequentially. The reaction was stirred at 20°C for 8 hours. After settling, the vessel was opened. The catalyst was removed by filtration. The organic phase was washed with aqueous sodium hydroxide solution, aqueous sodium bicarbonate solution, and water, respectively, dried with MgSO4, and distilled to obtain a 2.84 g fraction. Gas chromatography analysis showed no formation of the target substance.

Claims

1. A method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexene, comprising: 1,1,1,2,2,5,5,6,6,6-decafluorohexane was prepared by telomerization of 1,1-difluoroethane, tetrafluoroethylene and hydrogen fluoride under a catalyst, followed by halogenation and dehydrohalogenation reactions to prepare (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene. in: The telomerization reaction described in step (a) is as follows: 1,1-difluoroethane reacts with tetrafluoroethylene in the presence of a Lewis acid catalyst and anhydrous hydrofluoric acid to obtain 1,1,1,2,2,5,5,6,6,6-decafluorohexane. The halogenation reaction described in step (b) involves the thermal halogenation of 1,1,1,2,2,5,5,6,6,6-decafluorohexane with a halogen to produce 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane. The dehydrohalogenation reaction described in step (c) involves the removal of one molecule of hydrogen halide from 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane in a protic solvent under the action of a strong base, yielding (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene.

2. The method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexene according to claim 1, characterized in that: The Lewis catalyst mentioned in step (a) is any one of aluminum trifluoride, aluminum fluorochloride, and zirconium fluorochloride, and the molar ratio of 1,1-difluoroethane, tetrafluoroethylene, Lewis catalyst and anhydrous hydrofluoric acid is 1:2-4:0.01-0.2:1-5.

3. The method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene according to claim 1, characterized in that... The reaction temperature in step (a) is 0℃~100℃, and the reaction time is 1~24h.

4. The method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexene according to claim 1, characterized in that... The halogen mentioned in step (b) is either chlorine or bromine, and the molar ratio of 1,1,1,2,2,5,5,6,6,6-decafluorohexane to the halogen is 1:1 to 6.

5. The method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexene according to claim 1, characterized in that... The reaction temperature in step (b) is 150℃~400℃.

6. The method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohexene according to claim 1, characterized in that... The strong base mentioned in step (c) is any one of potassium hydroxide, sodium hydroxide, sodium carbonate, and potassium carbonate; the protic solvent is any one or a combination of water, methanol, ethanol, or isopropanol; and the molar ratio of 3-halo-1,1,1,2,2,5,5,6,6,6-decafluorohexane to the strong base is 1:1 to 2.

7. The method for preparing (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene according to claim 1, characterized in that... The reaction temperature in step (c) is 0℃~50℃, and the reaction time is 0.5~2h.

8. An application of a compound, characterized in that: The compound is selected from (E)-1,1,1,2,2,5,5,6,6,6-decafluorohex-3-ene prepared by any of the preparation methods described in claims 1-7. It is used as a working fluid in phase change immersion cooling systems in fields such as data centers, semiconductors, electronics, automobiles, and home appliances.

Images