A silicone coolant and a method for preparing the same

Abstract

The application discloses a kind of organic silicon coolant and preparation method thereof, product has low viscosity, high flash point, it is related to the application field of single-phase coolant for heat-dissipating of heat-generating equipment, specific method is: at 20-30 ℃, olefin and catalyst are mixed, temperature is raised to 35-45 ℃, hydrogen-containing siloxane is added drop by drop, control reaction liquid temperature is in the range of 60-130 ℃;After adding, continue stirring;After reaction, cooling, remove residual olefin, obtain final product, its general formula: (CH3) 3SiO-[R1R2SiO] n Si (CH3) 3;Wherein, R1=8-16 alkyl group;R2=methyl or trimethylsiloxy;N=1-2.The single-phase organic silicon coolant prepared by the application has the properties of high flash point, low viscosity, low surface tension, good flowability, more comprehensive coverage, better heat-dissipating effect, good material compatibility with data center, no swelling and other damage with related materials, safety and long-term effect.

Description

Technical Field

[0001] This invention relates to the field of single-phase coolants, and more specifically to an organosilicon coolant and its preparation method. Background Technology

[0002] With the widespread use of high-power chips, the heat generated during normal operation needs to be removed promptly to ensure proper functioning. If the heat inside chips and other electronic components cannot be quickly dissipated, it will accumulate over time, leading to temperature increases and ultimately causing component failure. Therefore, effective methods must be employed to remove the generated heat as quickly as possible to ensure the normal and stable operation of devices.

[0003] Current technologies typically use air circulation, or air cooling, to remove heat from data center equipment. However, air has a low thermal conductivity, making air cooling inefficient and insufficient for quickly and adequately cooling more powerful equipment. Compared to air, liquids have a much higher thermal conductivity, allowing for rapid heat removal through liquid conduction. The most effective heat dissipation method is to directly immerse the data center equipment in a fluid coolant.

[0004] The main direct coolants used in data center equipment on the market include fluorinated materials, mineral oil, polyalphaolefin (PAO) synthetic oil, and polydimethylsiloxane (PDMS). Fluorinated materials have relatively low boiling points, allowing for rapid vaporization and the removal of significant heat. However, their low boiling points also result in high vapor pressures during cooling, forcing the cooling system to withstand high pressures, which greatly increases manufacturing and operating costs. Furthermore, their low boiling points mean they evaporate easily, potentially exposing them to the environment, which is detrimental to ozone layer depletion. Mineral oil is inexpensive, but it often contains impurities such as sulfur and phosphorus that can corrode data center equipment. Additionally, mineral oil is flammable and degrades over time. Moreover, mineral oil tends to cause ethylene propylene diene monomer (EPDM) rubber to swell; when used as a direct coolant in contact with capacitors, this can lead to capacitor failure and ultimately server malfunction. While polyalphaolefin (PAO) synthetic oils contain fewer impurities than mineral oils, they still present issues regarding flammability and degradation over time. Like mineral oils, PAOs tend to cause EPDM rubber to swell, posing a risk of damage to data center equipment. PDMS, on the other hand, easily causes silicone rubber materials to swell and weakens the bond strength of silicone rubber adhesives, leading to easier separation of silicone-bonded components and thus increasing the likelihood of data center server malfunctions.

[0005] The Shanghai Communications Society has released the "Technical Specifications and Test Methods for Single-Phase Coolant in Immersion Liquid Cooling Systems for Data Centers" (Group Standard T / SHSIC 0202-2023), which requires the kinematic viscosity (25℃) of the coolant to be less than 20 mm². 2 / s, open flash point greater than 150℃; electrical performance indicators: dielectric strength greater than 30KV, dielectric constant less than 2.5; material compatibility: volume change rate of silicone rubber and EPDM rubber not greater than 20%. Patent CN116438502A discloses an alkyl-modified organosilicon oil (CH3)3SiO-[(CH3)2SiO] with a molecular structure similar to polydimethylsiloxane. m -[R(CH3)SiO] n -Si(CH3)3 is used as a direct coolant. However, its viscosity is greater than 25 mm. 2 / s. High viscosity reduces fluidity, requiring additional power to drive the liquid flow. Patent CN111777996B discloses a method to improve the compatibility of fluorocarbons with polysiloxane fluids by introducing long-chain alkyl functional groups into the side-chain Si-H functional groups of the polysiloxane fluid molecule through hydrosilylation reaction. The resulting mixture of fluorocarbon and modified polysiloxane fluid possesses phase change heat transfer capabilities. However, Novec1230 (accounting for 2%-30% of the coolant by mass) in this product is a fluorocarbon, which is detrimental to atmospheric environmental protection. Furthermore, European patent EP0641849A2 discloses a product with low viscosity but also a low flash point, posing safety risks. Summary of the Invention

[0006] The purpose of this invention is to at least solve one of the technical problems existing in the prior art, and to provide an organosilicon coolant and its preparation method, the product having the characteristics of low viscosity and high flash point.

[0007] The technical solution of the present invention is as follows:

[0008] An organosilicon coolant has the following general formula: (CH3)3SiO-[R1R2SiO] n -Si(CH3)3;

[0009] The structural formula is:

[0010] Wherein, R1 = alkyl groups of 8-16;

[0011] R2 = methyl or trimethylsiloxy; n = 1-2 (including equal to).

[0012] The present invention also discloses a method for preparing an organosilicon coolant. Under nitrogen purging, olefins and catalysts are mixed at 20-30°C, the temperature is raised to 35-45°C, and methylsiloxane is added dropwise while controlling the reaction temperature within the range of 60-130°C. After the addition is complete, stirring is continued. After the reaction is completed, the mixture is cooled to remove residual olefins and obtain the final product.

[0013] As a preferred embodiment of the present invention, the alkyl group has 8-16 carbon atoms.

[0014] As a preferred embodiment of the present invention, the hydrosiloxane is at least one selected from 1,1,1,3,5,5,5-heptamethyltrisiloxane, 3H,5H-octamethyltetrasiloxane, and tris(trimethylsiloxy)silane.

[0015] As a preferred embodiment of the present invention, the catalyst is an organoplasmic, palladium, or rhodium complex catalyst. Preferably, the metal catalyst is a platinum complex, including one or more of the following: isopropanol chloroplatinate solution, platinum-divinyldisilazane Karstedt platinum catalyst, platinum-allyl polyether Karstedt catalyst, and supported solid platinum catalyst, in an amount of 1-100 ppm.

[0016] Preferably, it has a flash point >150°C and a thickness <20 mm at 25°C. 2 Viscosity per second.

[0017] The beneficial effects of this invention are: the single-phase organosilicon coolant prepared by this invention has high flash point and low viscosity, low surface tension, good fluidity, more comprehensive coverage, and better heat dissipation effect. At the same time, it has good compatibility with data center materials, will not swell or cause other damage to related materials, and has safety and long-lasting effect. Detailed Implementation

[0018] The embodiments of the present invention are described in detail below. These embodiments are exemplary and are only used to explain the present invention, and should not be construed as limiting the invention. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in the art or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all commercially available conventional products.

[0019] It should be noted that Karstedt catalysts are organoplatinum complex catalysts, including platinum-divinyldisiloxanes and platinum-allyl polyethers.

[0020] Hydrogen-containing siloxanes: 1,1,1,3,5,5,5-heptamethyltrisiloxane, a product sold externally by the company, grade H-307, with a purity of 99%;

[0021] 3H,5H-octamethyltetrasiloxane is a product sold externally by the company, brand name H-804, with a purity of 95%.

[0022] Hydrogen-containing siloxanes: Preparation of tris(trimethylsiloxy)silane;

[0023] In a dry 1000mL three-necked flask, add 200g of hexamethyldisiloxane and 152g of trimethoxysilane, then add 6g of concentrated hydrochloric acid and 132g of distilled water. React at 10℃ for 5h, let stand to remove the acid layer, wash the oil layer with water 3 times until neutral, and then dry to obtain a mixture of hydrogen-containing siloxanes. Distill at 1-50KPa and 80-100℃ to obtain hydrogen-containing siloxanes with a purity of 99%.

[0024] Example 1: (CH3)3SiO-[(C 12 H 25 [)(CH3)SiO]-Si(CH3)3

[0025] Under nitrogen purging at 25°C, 201.5 g of 1-dodecene and 100 mg of Karstedt catalyst were added to a four-necked flask. While stirring, 222.1 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane was added dropwise at 40°C, maintaining the reaction temperature within 90°C ± 5°C. After the addition was complete, stirring continued for 3 hours. The product was distilled under reduced pressure to remove residual 1-dodecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate was the product of Example 1.

[0026] Example 2: (CH3)3SiO-[(C 16 H 33 [)(CH3)SiO]-Si(CH3)3

[0027] Under nitrogen purging and at 25°C, 246.7 g of 1-hexadecene and 100 mg of Karstedt catalyst were added to a four-necked flask. While stirring, 222.1 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane was added dropwise at 40°C, controlling the reaction temperature within the range of 130°C ± 5°C. After the addition was complete, stirring was continued for 3 hours. The product was distilled under reduced pressure to remove residual 1-hexadecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is from Example 2.

[0028] Example 3: (CH3)3SiO-[(C8H 17 [)(CH3)SiO]2-Si(CH3)3

[0029] Under nitrogen purging at 25°C, 123.3 g of 1-octene and 100 mg of Karstedt catalyst were added to a four-necked flask. While stirring, 141.0 g of 3H,5H-octamethyltetrasiloxane was added dropwise at 40°C, maintaining the reaction temperature within the range of 80°C ± 5°C. After the addition was complete, stirring continued for 3.5 hours. The product was distilled under reduced pressure to remove residual 1-octene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is the product of Example 3.

[0030] Example 4: (CH3)3SiO-[(C 12 H 25 [)(CH3)SiO]2-Si(CH3)3

[0031] Under nitrogen purging, 185.0 g of 1-dodecene and 100 mg of Karstedt catalyst were added to a four-necked flask at 25 °C. While stirring, 141.0 g of 3H,5H-octamethyltetrasiloxane was added dropwise at 40 °C, controlling the reaction solution temperature within the range of 90 °C ± 5 °C. After the addition was complete, stirring was continued for 3 hours. The product was distilled under reduced pressure to remove residual 1-dodecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is from Example 4.

[0032] Example 5: (CH3)3SiO-[(C 16 H 33 [)(CH3)SiO]2-Si(CH3)3

[0033] Under nitrogen purging, 246.7 g of 1-hexadecene and 100 mg of Karstedt catalyst were added to a four-necked flask at 25 °C. While stirring, 141.0 g of 3H,5H-octamethyltetrasiloxane was added dropwise at 40 °C, maintaining the reaction temperature within the range of 130 °C ± 5 °C. After the addition was complete, stirring was continued for 3 hours. The product was distilled under reduced pressure to remove residual 1-hexadecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is from Example 5.

[0034] Example 6: (CH3)3SiO-[(C 12 H 25 (CH3)SiO] 1.3 -Si(CH3)3

[0035] Under nitrogen purging at 25°C, 185.0 g of 1-dodecene and 100 mg of Karstedt catalyst were added dropwise to a four-necked flask. While stirring, 111.0 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane and 70.5 g of 3H,5H-octamethyltetrasiloxane were added dropwise at 40°C, maintaining the reaction temperature within the range of 80°C ± 5°C. After the addition was complete, stirring continued for 3 hours. The product was distilled under reduced pressure to remove residual 1-dodecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is from Example 6.

[0036] Example 7: (CH3)3SiO-[(C 16 H 33 (CH3)SiO] 1.3 -Si(CH3)3

[0037] Under nitrogen purging at 25°C, 246.7 g of 1-hexadecene and 100 mg of Karstedt catalyst were added to a four-necked flask. While stirring, 111.0 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane and 70.5 g of 3H,5H-octamethyltetrasiloxane were added dropwise at 40°C, maintaining the reaction temperature within the range of 130°C ± 5°C. After the addition was complete, stirring continued for 3 hours. The product was distilled under reduced pressure to remove residual 1-hexadecene. After adding 2% activated carbon, the mixture was stirred and filtered; the filtrate is the sample from Example 7.

[0038] Example 8: (CH3)3SiO-{(C 12 H 25 [(CH3)3SiO]SiO}-Si(CH3)3

[0039] Under nitrogen purging at 25°C, 100.0 g of 1-dodecene and 100 mg of Karstedt catalyst were added to a four-necked flask. While stirring, 148.0 g of tris(trimethylsiloxy)silane was added dropwise at 40°C, maintaining the reaction temperature within the range of 70°C ± 5°C. After the addition was complete, stirring was continued for 4 hours. The product was distilled under reduced pressure to remove residual 1-dodecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is the sample from Example 8.

[0040] Example 9: (CH3)3SiO-{(C 16 H 33 [(CH3)3SiO]SiO}-Si(CH3)3

[0041] Under nitrogen purging at 25°C, 135.0 g of 1-hexadecene and 100 mg of Karstedt catalyst were added to a four-necked flask. While stirring, 148.0 g of tris(trimethylsiloxy)silane was added dropwise at 40°C, maintaining the reaction temperature within the range of 80°C ± 5°C. After the addition was complete, stirring was continued for 4 hours. The product was distilled under reduced pressure to remove residual 1-hexadecene. After adding 2 wt% activated carbon, the mixture was stirred and filtered; the filtrate is the sample from Example 9.

[0042] Comparative Example 1: (CH3)3SiO-[(C8H 17 [)(CH3)SiO]-Si(CH3)3 is derived from the company's externally sold product H-034.

[0043] Comparative Example 2: (CH3)3SiO[(CH3)2Si)]3[(C 16 H 33 (CH3)SiO]6Si(CH3)3

[0044] Under nitrogen purging at 25°C, 224.3 g of 1-hexadecene and 97.5 mg of Karstedt catalyst were added dropwise to a four-necked flask. While stirring, 102.4 g of a hydrogen-containing polysiloxane with the molecular formula (CH3)3SiO-[(CH3)HSiO]6-[(CH3)2SiO]3-Si(CH3)3 was added dropwise at 70°C. ， The reaction solution temperature was controlled within the range of 70℃ to 80℃. After the addition was complete, stirring was continued for 4 hours. The resulting product was Comparative Example 2.

[0045] The material compatibility (silicone rubber and EPDM rubber) index requires that the volumetric mass change of the material before and after the experiment not exceed 20%. For comparative purposes, reference fluids such as dimethyl silicone oil, base oil, and PAO 3.5 were also characterized in the compatibility test and compared with Example 5. The results are shown in Table 1. The volumetric mass change of dimethyl silicone oil for silicone rubber was 108.24%, which is far greater than 20%, therefore it is unacceptable. The volumetric mass changes of base oil and PAO for EPDM rubber were -51.14% and -52.31%, respectively, which also exceeded the 20% range, therefore they were unacceptable. In contrast, the volumetric mass change of Example 5 for silicone rubber was 4.53%, and for EPDM rubber it was -1.05%, both within the range of less than 20%. This indicates that the examples have good compatibility with the relevant materials.

[0046] Table 1: Compatibility tests of different fluids on silicone rubber and EPDM rubber

[0047]

[0048]

[0049] In addition, the above embodiments and comparative examples were subjected to property and performance tests. The test methods were based on the "Technical Indicators and Test Methods for Single-Phase Coolant in Immersion Liquid Cooling Systems for Data Centers" (Group Standard T / SHSIC0202-2023) published by the Shanghai Communications Society. The requirement was that the kinematic viscosity (25℃) of the coolant should be less than 20 mm². 2 / s, the lower the viscosity, the better the flowability, and the less driving force is required, which is beneficial for reducing PUE (Power Usage Effectiveness); the open flash point should be greater than 150℃; electrical performance indicators: dielectric strength greater than 30KV, dielectric constant less than 2.5; material compatibility: the mass-volume change rate of silicone rubber and EPDM rubber should not exceed 20%. The smaller the change rate, the less corrosion to the equipment, and the more beneficial it is to the long-term stable operation of the equipment. The test results are shown in Table 2.

[0050] Table 2 shows that the flash point (130℃), thermal conductivity (0.112), and volumetric change of silicone rubber (54.74%) of Comparative Example 1 did not meet the group standard. The products obtained in the examples had higher flash points (all greater than 150℃) and met the group standard requirements in terms of electrical properties and compatibility. A higher flash point generally indicates better safety. Compared to the viscosity (45 cst) of Comparative Example 2, the products obtained in the examples all had lower viscosities (all less than 20 cst). Lower viscosity results in better flowability, more comprehensive coverage, and better heat dissipation. Regarding material compatibility with data centers, the products obtained in the examples showed a volumetric change rate of no more than 20% for both silicone rubber and EPDM rubber, demonstrating safety and long-lasting effectiveness.

[0051] The overall success of the example indicates that the number of carbon atoms in the R1 group must be between 8 and 16 (inclusive).

[0052] Examples 1, 2, 5, 6, 7, and 8 indicate that n is between 1 and 2 (inclusive).

[0053] Examples 1, 2, 9, and 10 show that R2 is methyl or trimethylsiloxy.

[0054] Among them, Examples 5 (R1 has 16 carbon atoms, R2 is methyl, n=2), 7 (R1 has 16 carbon atoms, R2 is methyl, n=1.3), and 9 (R1 has 16 carbon atoms, R2 is trimethylsiloxy, n=1) have higher flash points and smaller mass-volume changes in silicone rubber and EPDM rubber, that is, the products obtained by Examples 5, 7, and 9 have better performance.

[0055]

[0056]

[0057] The embodiments described above are merely preferred embodiments of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various other corresponding changes and modifications based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing an organosilicon coolant, characterized in that, The general formula for the organosilicon coolant is as follows: (CH3)3SiO-[R1R2SiO] n Si(CH3)3; Wherein, R1 is a straight-chain or branched alkyl group with 16 carbon atoms; R2 = methyl or trimethylsiloxy; n = 1 or 2; It has a flash point >150℃ and a temperature <20mm at 25℃. 2 Viscosity per second; The preparation method is as follows: Under nitrogen purging, the olefin and catalyst are mixed at 20-30℃, the temperature is raised to 30-45℃, and hydrogen-containing siloxane is added dropwise, while controlling the reaction solution temperature within the range of 60-130℃; after the addition is complete, stirring is continued; after the reaction is completed, the mixture is cooled to remove the residual olefin and obtain the final product. The hydrogen-containing siloxane is at least one of 1,1,1,3,5,5,5-heptamethyltrisiloxane, 3H,5H-octamethyltetrasiloxane, and tris(trimethylsiloxy)silane.

2. The method for preparing an organosilicon coolant according to claim 1, characterized in that: The catalyst is a complex containing palladium, rhodium, or platinum, and the addition amount is 1-300 ppm.

3. The method for preparing an organosilicon coolant according to claim 2, characterized in that: The catalyst is one or more of the following: isopropanol chloroplatinic acid solution, Karstedt platinum catalyst, platinum-allyl polyether catalyst and supported solid platinum catalyst, with an addition amount of 1-100 ppm.

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