Organic silicon cooling liquid and preparation method thereof

Abstract

The invention discloses an organic silicon cooling liquid and a preparation method thereof, the product has low viscosity and high flash point, and relates to the field of application of single-phase cooling liquid for heat dissipation of heating equipment, and the specific method comprises the following steps: uniformly mixing olefin and a catalyst at 20-30 DEG C, heating to 35-45 DEG C, dropwise adding hydrogen-containing siloxane, and controlling the temperature of the reaction liquid to be in a range of 60-130 DEG C; after adding, continuously stirring; cooling after the reaction is finished, and removing residual olefin to obtain a final product with a general formula of (CH3) 3SiO-[R1R2SiO] nSi (CH3) 3, wherein R1 is an alkyl group ranging from 8 to 16; r2 is a methyl group or a trimethylsiloxy group; n is equal to 1-2. The prepared single-phase organic silicon cooling liquid has the performance of high flash point and low viscosity, is low in surface tension, good in fluidity, more comprehensive in coverage, better in heat dissipation effect, good in compatibility with materials of a data center, free of swelling and other damage with related materials, and safe and long-acting.

Description

Technical Field

[0001] The invention relates to the field of single-phase coolants, and in particular to an organosilicon coolant and a preparation method thereof. Background Art

[0002] With the widespread use of high-power chips, the heat generated by the normal operation of the chip needs to be removed in time to ensure the normal operation of the device. If the heat inside the chip and other electronic devices cannot be removed quickly, the heat accumulation will cause the temperature to rise over time, which will lead to the failure of the electronic components. Therefore, effective means must be used to remove the generated heat as soon as possible to ensure the normal and stable operation of the device.

[0003] In the prior art, circulating air, or air cooling, is generally used to remove heat from data center equipment. However, the thermal conductivity of air is small, and the efficiency of air cooling is low, which is not enough to quickly and fully cool more powerful equipment. Compared with air, the thermal conductivity of liquid is much larger than that of air, so heat can be quickly removed by liquid conduction. The most effective way to dissipate heat is to directly immerse the data center equipment in fluid coolant.

[0004] The direct cooling fluids used for data center equipment on the market mainly include fluorinated materials, mineral oil, polyalphaolefin (PAO) synthetic oil and polydimethylsiloxane (PDMS), among which fluorinated materials have a relatively low boiling point and can be quickly vaporized to take away a large amount of heat. However, fluorinated materials have a relatively low boiling point, and a higher vapor pressure will be generated during the cooling and heat exchange process, which causes the cooling system to withstand high pressure, which greatly increases the manufacturing and operating costs of the cooling system. At the same time, the low boiling point means that these fluorinated materials are relatively easy to evaporate, which may cause the fluorinated materials to be exposed to the environment, and fluorinated materials are also destroyers of the atmospheric ozone layer, which is not conducive to the protection of the atmospheric environment. Mineral oil is cheap, but it usually contains impurities such as sulfur and phosphorus that may cause corrosion of data center equipment. In addition, mineral oil is flammable and easily degraded over time. In addition, mineral oil tends to swell ethylene propylene diene monomer (EPDM) rubber, which may cause capacitor failure in the server and ultimately cause server failure when used as a direct cooling fluid in contact with capacitors. Although polyalphaolefin (PAO) synthetic oils contain fewer impurities than mineral oils, there are still issues with flammability and degradation over time. And like mineral oils, PAOs also tend to swell EPDM rubbers, thus posing a risk of damaging data center equipment. PDMS tends to swell silicone rubber materials and weaken the bond strength of silicone rubber adhesive materials, making it easier for parts bonded to silicone rubber to separate, thus also causing failures in data center servers.

[0005] The Shanghai Institute of Communications has issued the "Technical Indicators and Test Methods for Single-Phase Cooling Liquid in Data Center Immersion Liquid Cooling Systems" (Group Standard T / SHSIC 0202-2023), which requires the kinematic viscosity (25°C) of the coolant to be less than 20mm 2 / s, open flash point greater than 150°C; electrical performance indicators: dielectric strength greater than 30KV, dielectric constant less than 2.5; material compatibility: silicone rubber and EPDM rubber mass volume change rate is not greater than 20%. Patent CN116438502A discloses an alkyl-modified organic silicone oil (CH3)3SiO-[(CH3)2SiO] with a molecular structure similar to polydimethylsiloxane m -[R(CH3)SiO] n -Si(CH3)3 as direct coolant. However, its viscosity is greater than 25mm 2 / s. When the viscosity is high, the fluidity is reduced, and additional power is needed to drive the liquid to flow. Patent CN111777996B discloses a method for improving the compatibility of fluorocarbon compounds and polysiloxane fluids by introducing long-chain alkyl functional groups into polysiloxane fluid molecules containing Si-H functional groups in the side chains through a hydrosilylation reaction. The prepared mixture of fluorocarbon compounds and modified polysiloxane fluids has the ability of phase change heat transfer. However, Novec1230 in this product (accounting for 2%-30% of the mass fraction of the coolant) is a fluorocarbon compound, which will be detrimental to the protection of the atmospheric environment. In addition, the product disclosed in European Patent EP0641849A2 has a low viscosity, but a low flash point, which poses a safety hazard. Summary of the invention

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

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

[0008] An organic silicon coolant, the general formula of which is as follows: (CH3)3SiO-[R1R2SiO] n -Si(CH3)3;

[0009] The structural formula is:

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

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

[0012] The present invention also discloses a method for preparing an organosilicon coolant, comprising the steps of mixing olefins and a catalyst at 20-30°C under nitrogen purge, heating the mixture to 35-45°C, adding methylsiloxane dropwise, and controlling the temperature of the reaction liquid to be within the range of 60-130°C; continuing to stir the mixture after the addition; cooling the mixture after the reaction is completed, removing residual olefins, and obtaining a 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 hydrogen siloxane is at least one of 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 organic platinum, palladium, or rhodium complex catalyst. Preferably, the metal catalyst is a platinum complex, including one or more of chloroplatinic acid isopropanol solution, platinum-divinyldisiloxane Karstedt platinum catalyst, platinum-allyl polyether Karstedt catalyst and supported solid platinum catalyst, and the addition amount is 1-100ppm.

[0016] Preferably, it has a flash point of >150°C and a thermal conductivity of <20 mm at 25°C. 2 / s viscosity.

[0017] The beneficial effects of the present invention are as follows: the single-phase silicone coolant prepared by the present invention has the properties of high flash point and low viscosity, low surface tension, good fluidity, more comprehensive coverage, better heat dissipation effect, and good compatibility with the materials of the data center, will not swell and cause other damage to related materials, and is safe and long-lasting. DETAILED DESCRIPTION

[0018] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. If no specific techniques or conditions are specified in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used that do not specify the manufacturer are all conventional products that can be obtained commercially.

[0019] It should be noted that the Karstedt catalyst is an organic platinum complex catalyst, including platinum-divinyldisiloxane and platinum-allyl polyether.

[0020] Hydrogen-containing siloxane: 1,1,1,3,5,5,5-heptamethyltrisiloxane, a product sold by the company, brand H-307, product purity 99%;

[0021] 3H,5H-octamethyltetrasiloxane is a product sold by the company, brand H-804, product purity 95%;

[0022] Hydrogenated siloxanes: preparation of tris(trimethylsiloxy)silane;

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

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

[0025] Under nitrogen purge, at 25°C, add 201.5 g of 1-dodecene and 100 mg of Karstedt catalyst to a four-necked flask. While stirring, add 222.1 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane dropwise at 40°C, and control the temperature of the reaction liquid to be within 90°C ± 5°C. After the addition, continue stirring for 3 hours. The product is distilled under reduced pressure to remove the residual 1-dodecene. After adding 2wt% activated carbon, stir and filter, and the filtrate is Example 1.

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

[0027] Under nitrogen purge, at 25°C, add 246.7 g of 1-hexadecene and 100 mg of Karstedt catalyst into a four-necked flask. While stirring, add 222.1 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane dropwise at 40°C, and control the temperature of the reaction liquid to be within the range of 130°C ± 5°C. After the addition, continue stirring for 3 hours. The product is distilled under reduced pressure to remove the residual 1-hexadecene. After adding 2wt% activated carbon, stir and filter, and the filtrate is Example 2.

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

[0029] Under nitrogen purge, 123.3 g of 1-octene 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, and the temperature of the reaction solution was controlled within the range of 80°C ± 5°C. After the addition, stirring was continued for 3.5 hours. The product was distilled under reduced pressure to remove the residual 1-octene. After adding 2 wt% of activated carbon, the mixture was stirred and filtered, and the filtrate was Example 3.

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

[0031] Under nitrogen purge, 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, and the temperature of the reaction solution was controlled within the range of 90°C ± 5°C. After the addition, stirring was continued for 3 hours. The product was distilled under reduced pressure to remove the residual 1-dodecene. After adding 2 wt% of activated carbon, the mixture was stirred and filtered, and the filtrate was Example 4.

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

[0033] Under nitrogen purge, 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, and the temperature of the reaction solution was controlled within the range of 130°C ± 5°C. After the addition, stirring was continued for 3 hours. The product was distilled under reduced pressure to remove the residual 1-hexadecene. After adding 2 wt% of activated carbon, the mixture was stirred and filtered, and the filtrate was Example 5.

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

[0035] Under nitrogen purge, at 25°C, add 185.0 g of 1-dodecene and 100 mg of Karstedt catalyst to a four-necked flask. While stirring, add 111.0 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane and 70.5 g of 3H,5H-octamethyltetrasiloxane dropwise at 40°C, and control the temperature of the reaction solution to be within the range of 80°C ± 5°C. After the addition, continue stirring for 3 hours. The product is distilled under reduced pressure to remove the residual 1-dodecene. After adding 2wt% activated carbon, stir and filter, and the filtrate is Example 6.

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

[0037] Under nitrogen purge, at 25°C, add 246.7 g of 1-hexadecene and 100 mg of Karstedt catalyst to a four-necked flask. While stirring, add 111.0 g of 1,1,1,3,5,5,5-heptamethyltrisiloxane and 70.5 g of 3H,5H-octamethyltetrasiloxane dropwise at 40°C, and control the temperature of the reaction liquid to be within the range of 130°C ± 5°C. After the addition, continue stirring for 3 hours. The product is distilled under reduced pressure to remove the residual 1-hexadecene. After adding 2% activated carbon, stir and filter, and the filtrate is Example 7.

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

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

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

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

[0042] Comparative Example 1: (CH3)3SiO-[(C8H 17 )(CH3)SiO]-Si(CH3)3 comes from the company's external sales product H-034.

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

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

[0045] The material compatibility (organic silicone rubber and EPDM rubber) index requires that the mass volume change of the material before and after the experiment is no more than 20%. For comparison purposes, reference fluids such as dimethyl silicone oil, base oil, PAO3.5, etc. were also characterized in the compatibility test and compared with Example 5, and the results are shown in Table 1. The mass volume change of dimethyl silicone oil on silicone rubber is 108.24%, which is much greater than 20%, so it is unqualified. The mass volume changes of base oil and PAO on EPDM rubber are -51.14% and -52.31%, respectively, which also exceed the range of 20%, so it is unqualified. The mass volume change of Example 5 on silicone rubber is 4.53, and the mass volume change on EPDM rubber is -1.05, both within the range of less than 20%. This shows that the embodiment has good compatibility with related materials.

[0046] Table 1: Compatibility test of different fluids with silicone rubber and EPDM rubber

[0047]

[0048]

[0049] In addition, the above-mentioned embodiments and comparative examples were tested for properties and performance, and the test method was based on the "Technical Indicators and Test Methods for Single-Phase Cooling Liquid in Data Center Immersed Liquid Cooling System" (Group Standard T / SHSIC0202-2023) issued by the Shanghai Institute of Communications. It requires that the kinematic viscosity (25°C) of the coolant be less than 20mm 2 / s, the smaller the viscosity, the better the fluidity, and the less driving force required, which is beneficial to reducing PUE (power consumption ratio); the open flash point should be greater than 150℃; electrical performance indicators: dielectric strength is greater than 30KV, dielectric constant is less than 2.5; material compatibility: the mass volume change rate of silicone rubber and EPDM rubber is not more than 20%, the smaller the change rate, the less corrosion to the equipment, and the more beneficial to the long-term stable operation of the equipment. The test results are shown in Table 2.

[0050] It can be seen from Table 2 that the flash point (130°C), thermal conductivity (0.112) and mass volume change (54.74%) of comparative example 1 do not meet the group standard. The products obtained in the examples have a higher flash point (all greater than 150°C) and meet the group standard requirements in terms of electrical properties and compatibility. The higher the flash point, the better the safety. Compared with the viscosity (45cst) of comparative example 2, the products obtained in the examples have a lower viscosity (all less than 20cst). The lower the viscosity, the better the fluidity, the more comprehensive the coverage, and the better the heat dissipation effect. In terms of material compatibility with data centers, the mass volume change rate of the products obtained in the examples for silicone rubber and EPDM rubber is no more than 20%, which is safe and long-lasting.

[0051] The examples are generally qualified, indicating that the number of carbon atoms in the R1 group must be between 8 and 16 (including equal to).

[0052] Embodiments 1, 2, 5, 6, 7 and 8 indicate that n is between 1 and 2 (including equal to).

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

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

[0055]

[0056]

[0057] The above-mentioned embodiments only express the preferred implementation modes of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, various other corresponding changes and deformations can be made according to the technical solutions and concepts described above, and all these changes and deformations should fall within the scope of protection of the claims of the present invention.

Claims

1. An organosilicon coolant, characterized in that: Its general formula is as follows: (CH3)3SiO-[R1R2SiO] n Si(CH3)3; Wherein, R1 = an alkyl group of 8-16; R2 = methyl or trimethylsilyloxy; n = 1-2 (including equal to).

2. The organic silicon coolant according to claim 1, characterized in that: It has a flash point of >150°C and a temperature of <20 mm at 25°C. 2 / s viscosity.

3. A method for preparing an organosilicon coolant, characterized in that: Under nitrogen purge, at 20-30°C, mix the olefin and the catalyst, raise the temperature to 35-45°C, add hydrogen-containing siloxane dropwise, and control the temperature of the reaction liquid to be in the range of 60-130°C; after the addition, continue stirring; after the reaction is completed, cool and remove the residual olefin to obtain the final product.

4. The method for preparing an organosilicon coolant according to claim 3, characterized in that: The alkyl group has 8 to 16 carbon atoms and is a straight chain or branched chain or phenyl-substituted alkyl group.

5. The method for preparing an organosilicon coolant according to claim 3, characterized in that: The hydrogen-containing siloxane is at least one of 1,1,1,3,5,5,5-heptamethyltrisiloxane, 3H,5H-octamethyltetrasiloxane and tris(trimethylsiloxy)silane.

6. The method for preparing an organosilicon coolant according to claim 3, characterized in that: The metal catalyst is a complex containing palladium, rhodium or platinum, and the added amount is 1-300 ppm.

7. The method for preparing an organosilicon coolant according to claim 6, characterized in that: The metal catalyst is a platinum complex, including one or more of chloroplatinic acid isopropanol solution, platinum-divinyldisiloxane Karstedt platinum catalyst, platinum-allyl polyether Karstedt catalyst and supported solid platinum catalyst, and the addition amount is 1-100 ppm.

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