Liquid-cooling working medium, and preparation method therefor and use thereof

Abstract

The present application belongs to the field of chemical engineering. Provided are a liquid-cooling working medium, and a preparation method therefor and the use thereof. The liquid-cooling working medium prepared by means of the preparation method provided by the present application is a hydrofluoroolefin mixture containing two substance components, namely CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3. The hydrofluoroolefin mixture is self-generated during the preparation process, and the two components do not need to be separated; and the hydrofluoroolefin mixture can be directly used as a two-phase immersion liquid-cooling working medium. The preparation method of the present application is of important significance to the preparation of a candidate working medium with good performance and a stable quality for an immersion cooling system, optimizes a synthesis process for a hydrofluoroolefin, and provides a whole-process preparation method for raw materials, an intermediate and a final product. The obtained final product has a stable quality and good performance; and the prepared liquid-cooling working medium has the advantages of efficient heat dissipation and temperature control, and can achieve the objectives of energy conservation and consumption reduction.

Description

Liquid cooling medium and preparation method and application thereof

[0001] The present application claims priority to the Chinese patent application No. CN 2024106513705, filed on May 23, 2024, and entitled "A liquid cooling medium and preparation method and application thereof", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0002] The present application relates to the field of chemical technology, in particular to a liquid cooling medium and preparation method and application thereof. BACKGROUND

[0003] Hydrofluoroolefins (Rf-CH=CH-R’f) have zero ODP (ozone depletion potential) and low GWP (global warming potential), and have environmental protection advantages. Compared with perfluoroolefins, hydrofluoroolefins have good structural stability, and the carbon-carbon double bond is not easy to shift and is not easy to acidify. Trans-Rf-CH=CH-Rf’ has low dielectric properties and has prospects in the application of immersion cooling in the electronic field.

[0004] The three non-terminal hydrofluoroolefins (E)-1,1,1,4,5,5,5-heptafluoro-4-trifluoromethyl-2-pentene (HFO-153-10mzzy), (E)-1,1,1,4,4,5,5,6,6,6-decafluoro-2-hexene (HFO-153-10mzz), and (E)-1,1,1,2,2,5,5,6,6,6-decafluoro-3-hexene (HFO-153-10mczz) have a molecular formula of C6H2F 10 , a boiling point (atmospheric pressure) of about 50℃, and a relative dielectric constant of about 2.0, and can be used as candidate working fluids for gas-liquid two-phase immersion cooling (2PIC) systems.

[0005] In the prior art, patents WO2018224908A1 and CN110709373A disclose an immersion cooling fluid system comprising HFO-153-10mzzy; patents US2023112841A1 and WO2023064123A1 disclose an immersion cooling system using low GWP fluids HFO-153-10mczz (E-F22E) and HFO-153-10mzzy (E-F13iE); patents WO2007059468, US2007152200A1, US2012175137A1, US8148584B2 and US9119982B2 disclose fire extinguishing and fire suppression compositions consisting of unsaturated fluorocarbons, wherein HFO-153-10mzzy is prepared by a two-step reaction: the first step is a 180°C thermally initiated free radical addition of carbon-carbon double bond of heptafluoroisopropyl iodide with 3,3,3-trifluoropropene (molar ratio: 1 / 1) to obtain a system containing 10-12% of raw material, 62% of mono-addition product and 12% of double-addition byproduct; the second step is a phase transfer catalytic condition, in which the intermediate is subjected to elimination reaction with potassium hydroxide at 75-100°C, and the product is obtained at a yield of 81%; patents US2007096051A1, US2007100010A1 and US2007098646A1 disclose fire extinguishing and fire suppression compositions consisting of unsaturated fluorocarbons, foam forming blowing agents consisting of unsaturated fluorocarbons, and aerosol propellants consisting of unsaturated fluorocarbons, including unsaturated fluorocarbons such as HFO-153-10mzzy (F13iE), HFO-153-10mczz (F13E) and HFO-153-10mzz (F22E). F13iE is prepared by a two-step reaction similar to the aforementioned thermal addition and base elimination: the first step is a 200°C thermally initiated addition of heptafluoroisopropyl iodide with 3,3,3-trifluoropropene (molar ratio: 2 / 1), and the intermediate product is obtained at a yield of 62% by reduced pressure distillation; the second step is an elimination reaction of the intermediate with potassium hydroxide at 42-62°C, and the product is obtained at a yield of 55% by atmospheric distillation; patents WO2022096995A1 and CN116472635A disclose an electronic component immersion cooling fluid system, and the synthesis of HFO-153-10mzzy is carried out according to US8148584B2, the first step is a diphenylmethanoyl peroxide initiated addition, and the intermediate product is obtained at a yield of 115°C fraction by purification, and the second step is an elimination reaction of the intermediate with potassium hydroxide, and the target product is obtained by water vapor distillation.

[0006] In the above preparation processes, the synthesis process of HFO-153-10mzz is not disclosed, and only the method for preparing HFO-153-10mzzy from the raw material heptafluoroisopropyl iodide is disclosed.

[0007] SUMMARY

[0008] Therefore, the present application aims to provide a liquid cooling medium and a preparation method and application thereof. The present application provides a new preparation method of a hydrogen fluoride alkene mixture for an immersion liquid cooling medium, which can be directly used in a two-phase liquid cooling medium and optimizes the synthesis process of hydrogen fluoride alkene.

[0009] In order to achieve the above-mentioned application purposes, the present application provides the following technical solutions:

[0010] The present application provides a preparation method of a liquid cooling medium, which is a mixture of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3, comprising the following steps:

[0011] Electrofluorination of a n-butyl compound in anhydrous hydrogen fluoride to obtain a mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride, absorption of the mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride by alkali liquor to obtain a mixture of perfluorobutyrate and perfluoroisobutyrate;

[0012] Thermal decomposition reaction of the mixture of perfluorobutyrate and perfluoroisobutyrate and elemental iodine in an anhydrous aprotic solvent to obtain a mixture of perfluoropropyl iodine and perfluoroisopropyl iodine;

[0013] Radical addition reaction of the mixture of perfluoropropyl iodine and perfluoroisopropyl iodine and 3,3,3-trifluoropropene to obtain an intermediate reaction liquid, which comprises CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3;

[0014] Treatment of the intermediate reaction liquid by alkali-alcohol mixed liquid to eliminate HI to obtain the liquid cooling medium.

[0015] Preferably, the n-butyl compound comprises one or more of n-butyryl chloride, n-butyryl fluoride and n-butyric acid.

[0016] Preferably, the molar ratio of the n-butyl compound to anhydrous hydrogen fluoride is 1:8-16.

[0017] Preferably, the temperature of the electrofluorination is -10-10℃.

[0018] Preferably, the molar ratio of the mixture of perfluorobutyrate and perfluoroisobutyrate to elemental iodine is 1:1-1.5.

[0019] Preferably, the temperature of the thermal decomposition reaction is 180-240℃ and the time is 4-8h.

[0020] Preferably, the mass percentage of perfluoropropyl iodine in the mixture of perfluoropropyl iodine and perfluoroisopropyl iodine is 80-98% and the mass percentage of perfluoroisopropyl iodine is 2-20%.

[0021] The application also provides the liquid cooling medium prepared by the preparation method, including CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3.

[0022] Preferably, the mass percentage of CF3CF2CF2CH=CHCF3 in the liquid cooling medium is 83-98.5%, and the mass percentage of (CF3)2CFCH=CHCF3 is 1.5-17%.

[0023] The application also provides the application of the liquid cooling medium in the two-phase immersion liquid cooling medium.

[0024] The application provides a preparation method of a liquid cooling medium, including the following steps: electrolytic fluorination of a n-butyl compound in anhydrous hydrogen fluoride to obtain a mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride; absorption of the mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride by alkali liquor to obtain a mixture of perfluorobutyrate and perfluoroisobutyrate; thermal decomposition reaction of the mixture of perfluorobutyrate and perfluoroisobutyrate and elemental iodine in an anhydrous aprotic solvent to obtain a mixture of perfluoropropyl iodine and perfluoroisopropyl iodine; free radical addition reaction of the mixture of perfluoropropyl iodine and perfluoroisopropyl iodine and 3,3,3-trifluoropropene to obtain an intermediate reaction liquid, and the intermediate reaction liquid includes CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3; and treatment of the intermediate reaction liquid by alkali-alcohol mixed liquid to remove HI to obtain the liquid cooling medium.

[0025] Compared with the prior art, the application has the following beneficial effects:

[0026] The liquid cooling medium prepared by the preparation method provided by the application is a hydrogen fluoride alkene mixture, including two components of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3, and the mixture is spontaneously generated in the preparation process and does not need to be separated, and can be directly used as a two-phase immersion liquid cooling medium. The preparation process method of the application has important significance for preparing a candidate working medium with excellent performance and stable quality for an immersion cooling system, optimizes the synthesis process of hydrogen fluoride alkene, and provides a whole-process preparation process method of raw materials, intermediates and final products. The final product has stable quality and excellent performance, and the prepared liquid cooling medium has the advantages of high-efficiency heat dissipation and temperature control, and can achieve the purpose of energy saving and consumption reduction. DETAILED DESCRIPTION

[0027] The application provides a preparation method of a liquid cooling medium, and the liquid cooling medium is a mixture of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3, including the following steps:

[0028] The n-butyl compound is electrolytic fluorination in anhydrous hydrogen fluoride to obtain a mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride, and the mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride is absorbed by lye to obtain a mixture of perfluorobutyrate and perfluoroisobutyrate;

[0029] The mixture of perfluorobutyrate and perfluoroisobutyrate is subjected to thermal decomposition reaction with elemental iodine in an anhydrous aprotic solvent to obtain a mixture of perfluoropropyl iodine and perfluoroisopropyl iodine;

[0030] The mixture of perfluoropropyl iodine and perfluoroisopropyl iodine and 3,3,3-trifluoropropene are subjected to radical addition reaction to obtain an intermediate reaction liquid, and the intermediate reaction liquid includes CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3;

[0031] The intermediate reaction liquid is treated by alkali-alcohol mixed liquid to eliminate HI to obtain the liquid cooling working medium.

[0032] In the present application, if no special description, the raw materials used are commercially available in the art.

[0033] In the present application, the n-butyl compound is electrolytic fluorination in anhydrous hydrogen fluoride to obtain a mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride, and the mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride is absorbed by lye to obtain a mixture of perfluorobutyrate and perfluoroisobutyrate.

[0034] In the present application, the n-butyl compound preferably includes one or more of n-butyryl chloride, n-butyryl fluoride and n-butyric acid.

[0035] In the present application, taking the n-butyl compound as n-butyryl chloride or n-butyryl fluoride as an example, the principle of preparing the mixture of perfluorobutyrate and perfluoroisobutyrate is shown in the following formula:

[0036] In the present application, the temperature of the electrolytic fluorination is preferably -10-10℃, more preferably -10℃, 0℃ or 10℃.

[0037] In the present application, the molar ratio of the n-butyl compound to anhydrous hydrogen fluoride is preferably 1:8-16, more preferably 1:8, 1:12 or 1:16.

[0038] In the process of the electrolytic fluorination in the present application, it is preferred to observe the electrolysis condition and constantly supplement the mixed liquid with a molar ratio of the n-butyl compound to anhydrous hydrogen fluoride ≤1 / 10.

[0039] In the present application, the alkali solution is preferably KOH solution or NaOH solution, and the mass concentration of the alkali solution is preferably 30-50%, more preferably 30%, 40% or 50%. When the alkali solution is KOH solution, a mixture of potassium perfluorobutyrate and potassium perfluoroisobutyrate is obtained, and when the alkali solution is NaOH solution, a mixture of sodium perfluorobutyrate and sodium perfluoroisobutyrate is obtained.

[0040] In the present application, the temperature of the alkali solution is preferably <20°C, more preferably 5°C.

[0041] In the present application, the temperature of the absorption is preferably <20°C, more preferably 15°C.

[0042] In the present application, after the absorption is completed, the solution after absorption is preferably subjected to a spray drying process for drying treatment, and white powder crystals, i.e. the mixture of perfluorobutyric acid salt and perfluoroisobutyric acid salt, are obtained.

[0043] In the present application, the temperature of the spray drying process is preferably 120°C.

[0044] In the present application, the moisture content of the white powder crystals is preferably <100 ppm.

[0045] In the present application, the white powder crystals preferably contain potassium / sodium fluoride salt or potassium / sodium chloride salt in addition to the mixture of perfluorobutyric acid salt and perfluoroisobutyric acid salt, and the potassium / sodium fluoride salt or potassium / sodium chloride salt has no effect on the subsequent preparation process and does not need to be separated and removed.

[0046] After the mixture of perfluorobutyric acid salt and perfluoroisobutyric acid salt is obtained, the mixture of perfluorobutyric acid salt and perfluoroisobutyric acid salt is subjected to a thermal decomposition reaction with iodine in anhydrous aprotic solvent to obtain a mixture of perfluoropropyl iodide and perfluoroisopropyl iodide.

[0047] In the present application, the principle of the thermal decomposition reaction is as shown in the following formula:

[0048] In the present application, the molar ratio of the mixture of perfluorobutyric acid salt and perfluoroisobutyric acid salt to iodine is preferably 1:1-1.5, more preferably 1:1, 1:1.3 or 1:1.5.

[0049] In the present application, the anhydrous aprotic solvent preferably includes at least one of NMP, DMAc, TMS, DMF, NBP, GVL, NFM, PC, NOP and 5-(dimethylamino)-2-methyl-5-oxopentanoic acid methyl ester (Polar Clean), more preferably NMP, DMF, NFM or 5-(dimethylamino)-2-methyl-5-oxopentanoic acid methyl ester (Polar Clean), and the moisture content of the anhydrous aprotic solvent is preferably ≤100 ppm, and the boiling point of the anhydrous aprotic solvent is preferably >150℃.

[0050] In the present application, the temperature of the thermal decomposition reaction is preferably 180-240℃, more preferably 180℃, 210℃ or 240℃, and the time is preferably 4-8h.

[0051] In the present application, the mass percentage of perfluoropropyl iodide in the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide is preferably 80-98%, and the mass percentage of perfluoroisopropyl iodide is preferably 2-20%.

[0052] In the present application, the yield of the thermal decomposition reaction is up to 85%.

[0053] After obtaining the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide, the present application carries out a free radical addition reaction on the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide and 3,3,3-trifluoropropene (HFO-1243zf) to obtain an intermediate reaction liquid, which includes CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3.

[0054] In the present application, the principle of the free radical addition reaction is as shown in the following formula:

[0055] In the present application, the molar ratio of the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide to HFO1243zf is preferably 1:1-1.5, more preferably 1:1, 1:1.3 or 1:1.5.

[0056] In the present application, the free radical addition reaction is preferably carried out at high temperature and high pressure, and the reaction conditions of the high temperature and high pressure are preferably as follows: the temperature is 160-220℃, the time is 8-20h, and the pressure is 1-6MPa; more preferably 160℃ / 20h, 190℃ / 14h or 220℃ / 8h, and for example, 160℃ / 20h, the " / " here means that the free radical addition reaction is carried out at 160℃ for 20h.

[0057] In the present application, the sum of the mass percentages of CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3 in the intermediate reaction liquid is preferably 60%-75%.

[0058] After obtaining the intermediate reaction solution, the intermediate reaction solution is treated with an alkali-alcohol mixture to eliminate HI, thereby obtaining the liquid cooling medium.

[0059] In the present application, the principle of treating the intermediate reaction solution with the alkali-alcohol mixture to eliminate HI is shown in the following formula: CF3CF2CF2CHICH2CF3+·(CF3)2CFCHICH2CF3..+KOH / alcohol→CF3CF2CF2CH=CHCF3+(CF3)2CFCH=CHCF3..+·KI+H2O.

[0060] In the present application, the alkali-alcohol mixture is preferably a KOH / alcohol solution or a NaOH / alcohol solution, and more preferably a KOH / methanol solution, a KOH / ethanol solution or a KOH / isopropanol solution.

[0061] In the present application, the alkali-alcohol mixture preferably further contains water.

[0062] In the present application, the volume of alcohol in the alkali-alcohol mixture is preferably 2 / 5, and the mass percentage of KOH or NaOH in the alkali-alcohol mixture is preferably 30%.

[0063] In the present application, the molar amount of the basic substance in the alkali-alcohol mixture is preferably twice the sum of the molar amounts of CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3.

[0064] In the present application, after the alkali-alcohol mixture is used to eliminate HI, the obtained reaction product includes CF3CF2CF2CH=CHCF3, (CF3)2CFCH=CHCF3, by-products, a small amount of unreacted perfluoropropyl iodide (CF3CF2CF2I) and perfluoroisopropyl iodide (CF3CFICF3).

[0065] In the present application, the target crude product obtained after the alkali-alcohol mixture is used to eliminate HI is preferably purified by rectification and impurities are removed, thereby obtaining the liquid cooling medium.

[0066] In the present application, the rectification purification is preferably performed in a rectification column, and a fraction between 40-52°C is collected, which contains CF3CF2CF2CH=CHCF3, (CF3)2CFCH=CHCF3 and very small amounts of CF3CF2CF2I and CF3CFICF3, and the content of CF3CFICF3 is preferably 0.

[0067] In the present application, the removing impurities preferably comprises the following steps: treating the fraction with NaHSO3 or Na2S2O4 solution, increasing the sum of mass content of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3 mixture to ≥99%, and decreasing the sum of mass content of CF3CF2CF2I and CF3CFICF3 to <0.001%.

[0068] The present application also provides a liquid cooling medium prepared by the above preparation method, comprising CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3.

[0069] In the present application, the mass percentage of CF3CF2CF2CH=CHCF3 in the liquid cooling medium is preferably 83-98.5%, and the mass percentage of (CF3)2CFCH=CHCF3 is preferably 1.5-17%.

[0070] In the present application, the boiling point of the liquid cooling medium is preferably 50±1℃, the latent heat of vaporization is preferably 112±3KJ / Kg, the kinematic viscosity is preferably 0.34cts (25℃), the thermal conductivity is preferably 0.068-0.071W / m·k, the dielectric constant is preferably 1.9-2.1 (1kHZ), the ODP value is preferably 0, and the GWP value is preferably less than 20.

[0071] The present application also provides the application of the liquid cooling medium in the two-phase immersion liquid cooling medium.

[0072] In the present application, the application preferably comprises the following steps: using the liquid cooling medium in an immersion liquid cooling heat dissipation system.

[0073] In the present application, the application preferably comprises using the liquid cooling medium in immersion liquid cooling heat dissipation in servers, data centers, energy storage, semiconductor manufacturing, charging equipment or new energy vehicle thermal management.

[0074] The technical solutions in the present application will be described clearly and completely in the present application combined with the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0075] Embodiments

[0076] The preparation method of the liquid cooling medium is carried out according to the following steps:

[0077] S1: n-Butyryl chloride is electrolytically fluorinated in anhydrous hydrogen fluoride to form a mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride. After absorption by alkaline solution (KOH solution) and drying to remove water, it becomes a mixture of potassium perfluorobutyrate and potassium perfluoroisobutyrate salt powders or a mixture of sodium salt powders.

[0078] The electrolysis process conditions are shown in Table 1. It can be seen that at lower electrolysis temperatures and higher anhydrous hydrogen fluoride content, the produced isobutyrate content is lower.

[0079] Table 1 Electrolysis process conditions

[0080] S2: A mixture of potassium perfluorobutyrate and potassium perfluoroisobutyrate (obtained in Examples 8, 3, or 19) reacts with elemental iodine in a high-boiling-point anhydrous aprotic solvent under high-temperature heating to decompose and release a mixture of perfluoropropyl iodine and perfluoroisopropyl iodine. Under different feed ratios, solvent types, and reaction temperatures, the yields and proportions of perfluoropropyl iodine and isopropyl iodine in the mixture vary. The feed reaction for preparing the mixture of perfluoropropyl iodine and isopropyl iodine is shown in Tables 2-4.

[0081] Table 2. Feeding reaction for preparing a mixture of perfluorinated n-propanediol and isopropanediol from Example 8.

[0082] Table 3. Feeding reaction for preparing a mixture of perfluorinated n-propiodine and isopropiodine in Example 3.

[0083] Table 4. Feeding reaction for preparing a mixture of perfluorinated n-propanediol and isopropanediol from Example 19

[0084] S3: The mixture of perfluoropropyl iodine and perfluoroisopropyl iodine in S2 was reacted with HFO-1243zf under high temperature and high pressure to obtain an intermediate reaction solution mainly composed of a mixture of CF3CF2CF2CHICH2CF3 and (CF3)2CFCHICHCF3; the molar ratio of the mixture of perfluoropropyl iodine and perfluoroisopropyl iodine to HFO1243zf was 1:1 to 1.5. The feed and yield data of the intermediate reaction solution are shown in Table 5.

[0085] The perfluoropropyl iodine / isopropyl iodine mixtures in Examples 64-66 were from the second group of Example 33; the perfluoropropyl iodine / isopropyl iodine mixtures in Examples 67-69 were from the second group of Example 41; and the perfluoropropyl iodine / isopropyl iodine mixtures in Examples 70-72 were from the third group of Example 45.

[0086] Table 5: Preparation of intermediate reaction liquid feed and intermediate yield data table

[0087] Note: In Table 5, intermediate A is CF3CF2CF2CHICH2CF3, and intermediate a is (CF3)2CFCHICHCF3.

[0088] S4: The mixture of intermediates CF3CF2CF2CHICH2CF3 and (CF3)2CFCHICHCF3 in S3 is treated with a base-alcohol mixture to eliminate HI to obtain the target crude product, and the elimination reaction temperature is 60°C. The base-alcohol mixture used is a 30% mass concentration KOH ethanol solution, and the amount of KOH used is 2 times the molar amount of the mixture of intermediates. After removing impurities by rectification purification, the hydrofluoroalkene mixture with the chemical structure CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3 for two-phase immersion liquid cooling working medium is obtained.

[0089] Depending on the ratio of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3 in the used intermediates, different proportions of the target liquid cooling working medium, the mixture of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3, can be prepared, with mass percentages of 83% to 98.5%: 17% to 1.5%.

[0090] The intermediate reaction liquid in Example 64 is treated with a base-alcohol mixture, and the product is purified by rectification to obtain the hydrofluoroalkene mixture of Example 76; the intermediate reaction liquid in Example 66 is treated with a base-alcohol mixture, and the product is purified by rectification to obtain the hydrofluoroalkene mixture of Example 77; the intermediate reaction liquid in Example 67 is treated with a base-alcohol mixture, and the product is purified by rectification to obtain the hydrofluoroalkene mixture of Example 78; the intermediate reaction liquid in Example 72 is treated with a base-alcohol mixture, and the product is purified by rectification to obtain the hydrofluoroalkene mixture of Example 79; the intermediate reaction liquid in Example 73 is treated with a base-alcohol mixture, and the product is purified by rectification to obtain the hydrofluoroalkene mixture of Example 80; the intermediate reaction liquid in Example 74 is treated with a base-alcohol mixture, and the product is purified by rectification to obtain the hydrofluoroalkene mixture of Example 81.

[0091] The physical property tests of the hydrofluoroalkene mixtures with different proportions of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3 are shown in Table 6.

[0092] Table 6: Hydrofluoroalkene mixture physical property test results

[0093] The hydrogen fluoroalkene mixture prepared by the above method comprises two components of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3, and the mixture is spontaneously generated in the preparation process of the application, without the need to separate the two. The hydrogen fluoroalkene mixture in different proportions described above can be directly used as the two-phase immersion liquid cooling medium. The preparation method provided by the application is of great significance for preparing candidate working fluids with excellent performance and stable quality for use in immersion cooling systems.

[0094] The mixed hydrogen fluoroalkene working fluid obtained from Examples 76-77 and 80-81 is applied to a two-phase immersion cooling system. The system has high heat dissipation and temperature control advantages, and can keep the temperature of the liquid cooling system within the range of 35-60°C, with obvious energy saving and consumption reduction advantages.

[0095] The hydrogen fluoroalkene mixture obtained from Examples 76, 77, 80 and 81 is used as a coolant, which is added to the sealed shell of the two-phase immersion cooling system and the coolant tank. A rack-mounted server Dell R750XS is immersed in the coolant, and the temperature change of the CPU element is observed after continuous operation for 48 h. Table 8 shows the results.

[0096] The substances used as coolants in Comparative Examples 1-7 are tested for various physical properties, as shown in Table 7.

[0097] Table 7 shows the results of the physical property tests of the coolants in Comparative Examples 1-7.

[0098] The substances commercially available in Comparative Examples 1-7 are used as coolants, which are added to the sealed shell of the two-phase immersion cooling system and the coolant tank. A rack-mounted server Dell R750XS is immersed in the coolant, and the temperature change of the CPU element is observed after continuous operation for 48 h. Table 8 shows the results.

[0099] Table 8 shows the results of the refrigeration effect test data.

[0100] Note: In Table 8, ①: CF3CF2CF2CH=CHCF3 / (CF3)2CFCH=CHCF3 is 83 / 17; ②: CF3CF2CF2CH=CHCF3 / (CF3)2CFCH=CHCF3 is 85.7 / 14.3; ③: CF3CF2CF2CH=CHCF3 / (CF3)2CFCH=CHCF3 is 95.2 / 4.8; ④: CF3CF2CF2CH=CHCF3 / (CF3)2CFCH=CHCF3 is 98.5 / 1.5.

[0101] The above merely describes the preferred embodiments of the present application, and does not constitute any form of limitation on the present application. It should be noted that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as falling within the scope of protection of the present application.

Claims

1. A method for producing a liquid cooling medium, characterized by, The liquid cooling medium is a mixture of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3, and the preparation method comprises the following steps: electrofluorination of a n-butyl compound in anhydrous hydrogen fluoride to obtain a mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride, absorption of the mixed gas of perfluorobutyryl fluoride and perfluoroisobutyryl fluoride by alkali liquor to obtain a mixture of perfluorobutyrate and perfluoroisobutyrate; thermal decomposition reaction of the mixture of perfluorobutyrate and perfluoroisobutyrate with elemental iodine in an anhydrous aprotic solvent to obtain a mixture of perfluoropropyl iodide and perfluoroisopropyl iodide; radical addition reaction of the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide with 3,3,3-trifluoropropene to obtain an intermediate reaction liquid, the intermediate reaction liquid comprising CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3; treatment of the intermediate reaction liquid by alkali-alcohol mixed liquid to eliminate HI to obtain the liquid cooling medium.

2. The production method according to claim 1, characterized by, The n-butyl compound comprises one or more of n-butyryl chloride, n-butyryl fluoride and n-butyric acid.

3. The production method according to claim 1 or 2, characterized by, The molar ratio of the n-butyl compound to anhydrous hydrogen fluoride is 1:8-16.

4. The method of claim 1, wherein, The temperature of the electrofluorination is -10-10°C.

5. The preparation method according to claim 1, characterized in that, During the electrofluorination, a mixture of the n-butyl compound and anhydrous hydrogen fluoride with a molar ratio ≤1 / 10 is supplemented.

6. The method of claim 1, wherein, The molar ratio of the mixture of perfluorobutyrate and perfluoroisobutyrate to elemental iodine is 1:1-1.

5.

7. The preparation method according to claim 1, characterized in that, The temperature of the thermal decomposition reaction is 180-240°C, and the time is 4-8h.

8. The method of claim 1, wherein, The mass percentage of perfluoropropyl iodide in the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide is 80-98%, and the mass percentage of perfluoroisopropyl iodide is 2-20%.

9. The method of claim 1, wherein, The molar ratio of the mixture of perfluoropropyl iodide and perfluoroisopropyl iodide to 3,3,3-trifluoropropene is 1:1-1.

5.

10. The production method according to claim 1 or 9, characterized by, The radical addition reaction is carried out under high temperature and high pressure, and the reaction conditions of the high temperature and high pressure include a temperature of 160-220°C, a time of 8-20h, and a pressure of 1-6MPa.

11. The method of claim 1, wherein, The sum of the mass percentages of CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3 in the intermediate reaction liquid is 60%-75%.

12. The method of claim 1, wherein, The molar amount of the basic substance in the alkali-alcohol mixed liquid is twice the sum of the molar amounts of CF3CF2CF2CHICH2CF3 and (CF3)2-CFCHICHCF3.

13. The method of claim 1, wherein, The target crude product obtained after treatment of the alkali-alcohol mixed liquid to eliminate HI is subjected to rectification purification and removal of impurities to obtain the liquid cooling medium.

14. The method of claim 13, wherein, The rectification purification is carried out in a rectification column, and a fraction with a temperature of 40-52°C is collected.

15. The production method according to claim 13 or 14, characterized by, The removing impurities comprises the following steps: treating the fraction obtained by the rectification purification with NaHSO3 or Na2S2O4 solution, increasing the sum of mass content of CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3 mixture to ≥99%, and decreasing the sum of mass content of CF3CF2CF2I and CF3CFICF3 to <0.001%.

16. The liquid cooling medium produced by the method of any one of claims 1 to 15, characterized by, CF3CF2CF2CH=CHCF3 and (CF3)2CFCH=CHCF3 are included.

17. The liquid cooling fluid of claim 16, wherein, The mass percentage of CF3CF2CF2CH=CHCF3 in the liquid cooling medium is 83-98.5%, and the mass percentage of (CF3)2CFCH=CHCF3 is 1.5-17%.

18. Use of the liquid cooling medium according to claim 16 or 17 as a two-phase immersion liquid cooling medium.

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