A method for preparing a fluorinated liquid with high thermal conductivity

Abstract

The present invention discloses a method for preparing a fluorinated liquid with high thermal conductivity, which specifically relates to an addition esterification reaction of perfluoroolefins and organic carboxylic acids. After the reaction, a fluorine-containing ester compound is generated. The fluorinated ester compound has excellent thermal conductivity, electrical insulation, chemical stability, thermal stability, low boiling point and other characteristics. The preparation method of the fluorinated liquid is as follows: perfluoroolefins and organic carboxylic acids undergo an addition esterification reaction of carbon-carbon double bonds and carboxyl oxygen-hydrogen bonds under a strong acid catalyst and heating conditions. The mixture after the reaction is washed with a weak alkaline solution and pure water in turn, and then separated and dried to obtain the target product. The target product is tested for thermal conductivity, and the thermal conductivity coefficient is greater than 0.2W / m·k. The water content is tested, and the water content is less than 50ppm. It can be applied to chip cooling systems, large server cooling systems, supercomputing data center cooling systems, new energy vehicle thermal management systems, etc.

Description

Technical Field

[0001] The invention relates to the technical field of fluorinated liquid preparation, and in particular to a method for preparing a fluorinated liquid with high thermal conductivity. Background Art

[0002] Fluorinated liquid is a chemical solvent that is colorless, transparent, odorless, safe and non-toxic. Perfluorinated liquid has excellent dielectric constant, stable chemical inertness, good thermal conductivity, extremely low surface tension and kinematic viscosity, and system compatibility. Its insulating and non-flammable inert characteristics are used as cooling liquid in data centers and are the most widely used submerged coolant so far.

[0003] Fluorinated liquid products are used for precision temperature control and cooling in semiconductors, liquid crystals and other high value-added electronic industries. They can also be used as refrigerants in data centers and power cooling. They are also widely used in defense and military industry, aerospace, electronics, semiconductors, automobiles, machinery, chemicals, textiles, construction, medicine and other fields.

[0004] Fluorinated liquid products have the following characteristics: 1. Permeability: low viscosity, extremely low surface tension, can penetrate into tiny gaps, and small viscosity changes at low temperatures. 2. Chemical properties: excellent thermal conductivity, thermal stability, and chemical stability. 3. Drying: moderate boiling point, low heat of vaporization during evaporation, fast evaporation rate, excellent drying, short drying time, water removal, and no water marks. 4. Impact on solid materials: excellent material compatibility, will not damage the surface of plastics, resins, metals and other materials. 5. Regeneration: can be distilled and regenerated, can be used repeatedly, and reduce costs. 6. Electrical insulation: very stable and does not change with temperature changes.

[0005] Currently, the main fluorinated liquid products on the market are 3M's FC series, and their thermal conductivity is generally <0.1W / (m·k). Its application in heat dissipation in the fields of servers, semiconductor chips, etc. has its limitations. In order to solve the problem of low thermal conductivity of current commercial products, the present invention is specially proposed. It can meet the increasingly high heat dissipation requirements of chip heat dissipation systems, large server heat dissipation systems, supercomputing data center heat dissipation systems, and new energy vehicle thermal management systems. Summary of the invention

[0006] The purpose of the present invention is to solve the above-mentioned problem and to propose a method for preparing a high thermal conductivity fluorinated liquid.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A method for preparing a fluorinated liquid with high thermal conductivity comprises an addition esterification reaction of a perfluoroolefin and an organic carboxylic acid, and a fluorine-containing ester compound is generated after the reaction. The compound is a fluorinated liquid with high thermal conductivity and low dielectricity. The method is characterized in that the perfluoroolefin and the organic carboxylic acid are subjected to an addition esterification reaction under a strong acid catalyst and heating conditions, and the carbon-carbon double bond in the perfluoroolefin and the carboxyl oxygen-hydrogen bond undergo an addition esterification reaction, and the mixed liquid after the reaction is washed with a weak alkaline solution and pure water in sequence, and then separated and dried to obtain the target product.

[0009] Preferably, the perfluoroolefin is one of: hexafluoropropylene dimer, perfluoro(4-methyl-2-pentene), perfluoro(2-methyl-2-pentene), perfluorocyclopentene, perfluorohex-1-ene, hexafluoropropylene trimer, perfluorobutylethylene, perfluorodecylethylene, hexafluoro-1,3-butadiene, perfluorohexylethylene, dodecafluoro-1,9-decadiene, and 6H-perfluoro-1-hexene.

[0010] Preferably, the organic carboxylic acid is one of formic acid, acetic acid, propionic acid, trifluoroacetic acid, difluoroacetic acid, monofluoroacetic acid, pentafluoropropionic acid, 2,3,3,3-tetrafluoropropionic acid, and 3,3,3-trifluoropropionic acid.

[0011] Preferably, the strong acid catalyst is one of concentrated sulfuric acid, phosphotungstic acid, silicotungstic acid and phosphomolybdic acid.

[0012] Preferably, the heating conditions are as follows: depending on the type of raw materials selected, the starting temperature of the heating reaction is controlled at 70°C-150°C.

[0013] Preferably, the carbon-carbon double bond in the perfluoroolefin undergoes an addition esterification reaction with the carboxyl oxygen-hydrogen bond: an organic carboxylic acid containing a strong acid catalyst is used as a reaction substrate, and the perfluoroolefin is added dropwise to the reaction substrate to carry out an esterification addition reaction under heating conditions.

[0014] Preferably, the mixed liquid after the reaction is washed with a weak alkaline solution and pure water in sequence, and then the target product is obtained after separation: sodium carbonate or sodium bicarbonate solution is added to the mixed liquid after the reaction, stirred and washed, and then separated, the lower layer product is collected, and pure water is added to the lower layer product, stirred and washed, and the lower layer product is separated again to obtain a high thermal conductivity fluorinated liquid.

[0015] Preferably, after the lower layer product is dried and dehydrated with calcium oxide, the moisture content of the product is required to be less than 50ppm, so that a high thermal conductivity fluorinated liquid can be obtained.

[0016] Preferably, the high thermal conductivity fluorinated liquid satisfies the thermal conductivity coefficient>0.2W / (m·K) and the water content<50ppm after testing.

[0017] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0018] 1. At present, the thermal conductivity of the fluorinated liquid products on the market is generally <0.1W / (m·k). In order to improve the overall low thermal conductivity of the common fluorinated liquids on the market, the thermal conductivity of the target fluorinated liquid product obtained by the present invention is greatly improved, the thermal conductivity coefficient is >0.2W / (m·K), and the dielectric constant is low and the insulation performance is good. The variety of immersion coolants has been expanded.

[0019] 2. The present invention fully takes into account "atom economy", the addition esterification reaction, the reaction conditions are mild and controllable, the utilization rate of the reactants in the raw materials is high, and the product yield is high.

[0020] 3. The post-processing and purification operation of the product of the present invention is convenient and simple, green and pollution-free, and has good economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic structural diagram of a fluorinated liquid preparation process according to an embodiment of the present invention is shown; DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] like Figure 1 The illustrated embodiment is as follows:

[0024] Example 1

[0025] Perfluoro(4-methyl-2-pentene) and formic acid are used as raw materials, concentrated sulfuric acid (98.3%) is used as a catalyst, and the initial temperature of the heating reaction is controlled at 70°C. 55.2g of formic acid is weighed and put into a reactor connected to a condensation reflux device and electrically stirred. The function of the condensation reflux device is to reduce the volatilization loss of the reaction raw materials and ensure that the pressure in the reactor is normal pressure. The temperature of the reactor is increased and the electric stirring is turned on. When the temperature of formic acid reaches 70°C, 17.8g of concentrated sulfuric acid (98.3%) as a catalyst is added at one time, and then 300g of perfluoro(4-methyl-2-pentene) is added dropwise to the reactor using a constant pressure dropping funnel. The dropping time is controlled to 1hrs. After the dropping is completed, the external heating temperature is maintained at 70°C, and it is allowed to continue to stir and react for 5hrs.

[0026] The amount of reactants is measured by the molar ratio of reactive functional groups, and the molar ratio of reactive functional groups is controlled to be: carbon-carbon double bond: carboxyl oxygen-hydrogen bond = 1:1.2, and formic acid is excessive to inhibit side reactions and hydrolysis reactions of products. The reaction process includes using an organic carboxylic acid containing a strong acid catalyst as a reaction substrate, the amount of the strong acid catalyst being 5% of the total mass of the reaction raw materials, and dropping a perfluoroolefin into the reaction substrate to carry out an esterification addition reaction under heating and stirring conditions.

[0027] The mixed solution after the reaction is washed with a weak alkaline solution and pure water in sequence, and then separated and dried to obtain the target product: that is, sodium carbonate or sodium bicarbonate solution is added to the mixed solution after the reaction, stirred and washed, and then separated, and the process is repeated 3 times, and the lower layer product is collected, and then pure water is added to the lower layer product, stirred and washed, and the process is repeated 5 times, and the lower layer product is separated again and collected. After the product is dried with calcium oxide, a high thermal conductivity and low dielectric fluoride liquid can be obtained.

[0028] Example 2

[0029] Perfluoro(4-methyl-2-pentene) and acetic acid are used as raw materials, concentrated sulfuric acid (98.3%) is used as a catalyst, and the initial temperature of the heating reaction is controlled at 90°C. 72g of acetic acid is weighed and put into a reactor connected to a condensation reflux device and electrically stirred. The function of the condensation reflux device is to reduce the volatilization loss of the reaction raw materials and ensure that the pressure in the reactor is normal pressure. The temperature of the reactor is increased and the electric stirring is turned on. When the temperature of acetic acid reaches 90°C, 18.6g of concentrated sulfuric acid (98.3%) as a catalyst is added at one time, and then 300g of perfluoro(4-methyl-2-pentene) is added dropwise to the reactor using a constant pressure dropping funnel. The dropping time is controlled to 1hrs. After the dropping is completed, the external heating temperature is maintained at 90°C, and the reaction is continued to be stirred for 5hrs.

[0030] The amount of reactants is measured by the molar ratio of reactive functional groups, and the molar ratio of reactive functional groups is controlled to be: carbon-carbon double bond: carboxyl oxygen-hydrogen bond = 1:1.2, and acetic acid is excessive to inhibit side reactions and hydrolysis reactions of products. The reaction process includes using an organic carboxylic acid containing a strong acid catalyst as a reaction substrate, the amount of the strong acid catalyst being 5% of the total mass of the reaction raw materials, and dripping a perfluoroolefin into the reaction substrate to carry out an esterification addition reaction under heating conditions.

[0031] The mixed solution after the reaction is washed with a weak alkaline solution and pure water in turn, and then separated and dried to obtain the target product: that is, sodium carbonate or sodium bicarbonate solution is added to the mixed solution after the reaction, stirred and washed, and then separated, and the process is repeated 3 times, and the lower layer product is collected, and then pure water is added to the lower layer product and stirred and washed, and the process is repeated 5 times, and the lower layer product is separated again and collected, and the product is dried with calcium oxide to obtain a high thermal conductivity and low dielectric fluoride liquid

[0032] Example 3

[0033] Perfluoro(4-methyl-2-pentene) and trifluoroacetic acid are used as raw materials, concentrated sulfuric acid (98.3%) is used as a catalyst, and the initial temperature of the heating reaction is controlled at 70°C. 136.8g of trifluoroacetic acid is weighed and put into a reactor connected to a condensation reflux device and electrically stirred. The function of the condensation reflux device is to reduce the volatilization loss of the reaction raw materials and ensure that the pressure in the reactor is normal pressure. The temperature of the reactor is increased and the electric stirring is turned on. When the temperature of the trifluoroacetic acid reaches 70°C, 21.84g of concentrated sulfuric acid (98.3%) as a catalyst is added at one time, and then 300g of perfluoro(4-methyl-2-pentene) is added dropwise to the reactor using a constant pressure dropping funnel. The dropping time is controlled to 1hrs. After the dropping is completed, the external heating temperature is maintained at 90°C, and it is allowed to continue to stir and react for 5hrs.

[0034] The amount of reactants is measured by the molar ratio of reactive functional groups, and the molar ratio of reactive functional groups is controlled to be: carbon-carbon double bond: carboxyl oxygen-hydrogen bond = 1:1.2, and trifluoroacetic acid is excessive to inhibit side reactions and hydrolysis reactions of products. The reaction process includes using an organic carboxylic acid containing a strong acid catalyst as a reaction substrate, the amount of the strong acid catalyst being 5% of the total mass of the reaction raw materials, and dripping a perfluoroolefin into the reaction substrate to carry out an esterification addition reaction under heating conditions.

[0035] The mixed solution after the reaction is washed with a weak alkaline solution and pure water in turn, and then separated and dried to obtain the target product: that is, sodium carbonate or sodium bicarbonate solution is added to the mixed solution after the reaction, stirred and washed, and then separated, and the process is repeated 3 times, and the lower layer product is collected, and then pure water is added to the lower layer product and stirred and washed, and the process is repeated 5 times, and the lower layer product is separated again and collected, and the product is dried with calcium oxide to obtain a high thermal conductivity and low dielectric fluoride liquid

[0036] Example 4

[0037] Perfluorobutylethylene and acetic acid are used as raw materials, phosphotungstic acid is used as a catalyst, and the starting temperature of the heating reaction is controlled at 100°C. Weigh 72g of acetic acid and put it into a reactor connected to a condensation reflux device and electrically stirred. The function of the condensation reflux device is to reduce the volatilization loss of the reaction raw materials and ensure that the pressure in the reactor is normal pressure. Raise the temperature of the reactor and turn on the electric stirring. When the temperature of acetic acid reaches 100°C, add 15.9g of phosphotungstic acid, a catalyst, at one time, and then use a constant pressure dropping funnel to drop 246g of perfluorobutylethylene into the reactor. The dropping time is controlled to 1hrs. After the dropping is completed, maintain the external heating temperature at 100°C and continue to stir and react for 5hrs.

[0038] The amount of reactants is measured by the molar ratio of reactive functional groups, and the molar ratio of reactive functional groups is controlled to be: carbon-carbon double bond: carboxyl oxygen-hydrogen bond = 1:1.2, and acetic acid is excessive to inhibit side reactions and hydrolysis reactions of products. The reaction process includes using an organic carboxylic acid containing a strong acid catalyst as a reaction substrate, the amount of the strong acid catalyst being 5% of the total mass of the reaction raw materials, and dripping a perfluoroolefin into the reaction substrate to carry out an esterification addition reaction under heating conditions.

[0039] The mixed solution after the reaction is washed with a weak alkaline solution and pure water in turn, and then separated and dried to obtain the target product: that is, sodium carbonate or sodium bicarbonate solution is added to the mixed solution after the reaction, stirred and washed, and then separated, and the process is repeated 3 times, and the lower layer product is collected, and then pure water is added to the lower layer product and stirred and washed, and the process is repeated 5 times, and the lower layer product is separated again and collected, and the product is dried with calcium oxide to obtain a high thermal conductivity and low dielectric fluoride liquid

[0040] Example 5

[0041] Perfluorohexylethylene and monofluoroacetic acid are used as raw materials, silicotungstic acid is used as a catalyst, and the starting temperature of the heating reaction is controlled at 150°C. Weigh 93.6g of monofluoroacetic acid and put it into a reactor connected to a condensation reflux device and electrically stirred. The function of the condensation reflux device is to reduce the volatilization loss of the reaction raw materials and ensure that the pressure in the reactor is normal pressure. Raise the temperature of the reactor and turn on the electric stirring. When the temperature of monofluoroacetic acid reaches 150°C, add 22.0g of silicotungstic acid as a catalyst at one time, and then use a constant pressure dropping funnel to drop 346g of perfluorohexylethylene into the reactor. The dropping time is controlled to 1hrs. After the dropping is completed, maintain the external heating temperature at 150°C and continue to stir and react for 5hrs.

[0042] The amount of reactants is measured by the molar ratio of reactive functional groups, and the molar ratio of reactive functional groups is controlled to be: carbon-carbon double bond: carboxyl oxygen-hydrogen bond = 1:1.2, and monofluoroacetic acid is excessive to inhibit side reactions and hydrolysis reactions of products. The reaction process includes using an organic carboxylic acid containing a strong acid catalyst as a reaction substrate, the amount of the strong acid catalyst being 5% of the total mass of the reaction raw materials, and dripping a perfluoroolefin into the reaction substrate to carry out an esterification addition reaction under heating conditions.

[0043] The mixed solution after the reaction is washed with a weak alkaline solution and pure water in sequence, and then separated and dried to obtain the target product: that is, sodium carbonate or sodium bicarbonate solution is added to the mixed solution after the reaction, stirred and washed, and then separated, and the process is repeated 3 times, and the lower layer product is collected, and then pure water is added to the lower layer product, stirred and washed, and the process is repeated 5 times, and the lower layer product is separated again and collected. After the product is dried with calcium oxide, a high thermal conductivity and low dielectric fluoride liquid can be obtained.

[0044] Example 6

[0045] Take dodecafluoro-1,9-decadiene and propionic acid as raw materials, concentrated sulfuric acid as catalyst, and heat the reaction starting temperature to 120°C. Weigh 88.8g of propionic acid and put it into a reactor connected to a condensation reflux device and electrically stirred. The function of the condensation reflux device is to reduce the volatilization loss of the reaction raw materials and ensure that the pressure in the reactor is normal pressure. Raise the temperature of the reactor and turn on the electric stirring. When the temperature of propionic acid reaches 120°C, add 22.2g of concentrated sulfuric acid (98.3%) as a catalyst at one time, and then use a constant pressure dropping funnel to drop 354g of dodecafluoro-1,9-decadiene into the reactor. Control the dropping time for 1hrs. After the dropping is completed, maintain the external heating temperature at 120°C and continue to stir and react for 5hrs.

[0046] The amount of reactants is measured by the molar ratio of reactive functional groups, and the molar ratio of reactive functional groups is controlled to be: carbon-carbon double bond: carboxyl oxygen-hydrogen bond = 1:1.2, and propionic acid is excessive to inhibit side reactions and hydrolysis reactions of products. The reaction process includes using an organic carboxylic acid containing a strong acid catalyst as a reaction substrate, the amount of the strong acid catalyst being 5% of the total mass of the reaction raw materials, and dripping perfluoroolefin into the reaction substrate to carry out an esterification addition reaction under heating conditions.

[0047] The mixed solution after the reaction is washed with a weak alkaline solution and pure water in sequence, and then separated and dried to obtain the target product: that is, sodium carbonate or sodium bicarbonate solution is added to the mixed solution after the reaction, stirred and washed, and then separated, and the process is repeated 3 times, and the lower layer product is collected, and then pure water is added to the lower layer product, stirred and washed, and the process is repeated 5 times, and the lower layer product is separated again and collected. After the product is dried with calcium oxide, a high thermal conductivity and low dielectric fluoride liquid can be obtained.

[0048] In the above embodiment, a method for preparing a high thermal conductivity and low dielectric fluorinated liquid is provided. The thermal conductivity of the post-processed product is tested using a laser thermal conductivity meter. According to the thermal conductivity data obtained after the test, the products all exhibit high thermal conductivity (the thermal conductivity of commercially available immersion fluorinated liquids is generally 0.04-0.07 W / m·k). The moisture content is tested by a moisture content tester, and the moisture content is <50 ppm.

[0049] The thermal conductivity data are as follows:

[0050] Serial number Thermal conductivity (W / (m·k)) Moisture content (ppm) Example 1 0.23 33 Example 2 0.25 29 Example 3 0.36 34 Example 4 0.31 41 Example 5 0.28 44 Example 6 0.33 21

[0051] The above description of the embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a high thermal conductivity fluorinated liquid, comprising reacting a perfluoroolefin with an organic carboxylic acid to generate a fluorinated ester compound, It is characterized in that The preparation method is as follows: perfluoroolefin and organic carboxylic acid undergo addition esterification reaction under strong acid catalyst and heating conditions, the mixed liquid after the reaction is washed with weak alkaline solution and pure water in sequence, and then separated and dried to obtain the target product; The perfluoroolefin is one of hexafluoropropylene dimer, perfluoro(4-methyl-2-pentene), perfluoro(2-methyl-2-pentene), perfluorocyclopentene, perfluorohex-1-ene, hexafluoropropylene trimer, perfluorobutylethylene, perfluorodecylethylene, hexafluoro-1,3-butadiene, perfluorohexylethylene, dodecafluoro-1,9-decadiene, and 6H-perfluoro-1-hexene; The organic carboxylic acid is one of formic acid, acetic acid, propionic acid, trifluoroacetic acid, difluoroacetic acid, monofluoroacetic acid, pentafluoropropionic acid, 2,3,3,3-tetrafluoropropionic acid, and 3,3,3-trifluoropropionic acid; The strong acid catalyst is one of concentrated sulfuric acid, phosphotungstic acid, silicotungstic acid and phosphomolybdic acid; The heating conditions are as follows: depending on the type of raw materials used, the starting temperature of the heating reaction is controlled at 70°C - 150°C; The thermal conductivity of the high thermal conductivity fluorinated liquid is greater than 0.2 W / (m·K).

2. A method for preparing a high thermal conductivity fluorinated liquid according to claim 1, It is characterized in that The mixed liquid after the reaction is washed with a weak alkaline solution and pure water in sequence, and then separated and dried to obtain the target product: sodium carbonate or sodium bicarbonate solution is added to the mixed liquid after the reaction, stirred and washed, and then separated, the lower layer product is collected, and pure water is added to the lower layer product to stir and wash, and the lower layer product is separated again to obtain a high thermal conductivity fluorinated liquid.

3. A method for preparing a high thermal conductivity fluorinated liquid according to claim 2, It is characterized in that After the lower layer product is dried and dehydrated by calcium oxide, the moisture content of the product is required to be less than 50ppm, and a high thermal conductivity fluorinated liquid can be obtained.

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