Silicon-based cooling liquid and preparation method and application thereof

Abstract

This invention relates to the fields of semiconductor processing and data center liquid cooling technology, specifically to a silicon-based coolant, its preparation method, and its applications. The coolant of this invention has the following chemical structure: R1(R2)2SiO-[(CH3)2SiO] m -Si(R3)2R4, wherein: R1 and R4 are alkyl groups with 8 or more but less than or equal to 14 carbon atoms, R2 and R3 are methyl, ethyl, or isopropyl groups, and 6 ≤ m < 14. The preparation method includes: under an inert gas atmosphere, mixing and reacting a methylcyclosiloxane, a difunctional hydrogen-containing alkylsiloxane end-capping agent, and a first catalyst; after the reaction, separating the first catalyst to obtain an intermediate product; mixing a second catalyst with a C8-C14 olefin, adding the intermediate product dropwise to react, and obtaining a crude product; and distilling the crude product under reduced pressure to obtain the final product. The silicon-based coolant of this invention possesses both a high flash point and low viscosity, with a viscosity < 35 mmHg when the flash point is > 240°C. 2 / s, exhibiting good physical and chemical stability; the coolant preparation method of the present invention ensures thorough reaction, with no hydrogen generation in post-processing, and high safety.

Description

Technical Field

[0001] This invention relates to the fields of semiconductor processing and data center liquid cooling technology, specifically to a silicon-based coolant and its preparation method and application. Background Technology

[0002] With the development of modern society, economy, and technology, the demand for computing power is rapidly increasing, and the integration of semiconductor chips is becoming increasingly sophisticated, resulting in greater heat generation. Efficient heat dissipation is crucial for ensuring stable equipment operation. Statistics show that over one-third of the energy consumed in data center operations is used for cooling IT equipment. Compared to air cooling, liquid cooling is more efficient. Commonly used coolants in liquid cooling technology fall into three main categories: fluorocarbons, hydrocarbons, and organosilicon compounds. Fluorocarbons are limited in use due to cost and environmental concerns; hydrocarbons are prone to hydrocarbon oxidization over long periods, forming corrosive substances; and organosilicon compounds can lead to excessive viscosity when a high flash point is required. Maintaining both a high flash point and low viscosity would significantly expand the application range of silicone oils.

[0003] Introducing alkyl groups into the side chains of organosilicon can yield silicone oils with high flash points and low viscosity. The alkane in the side chain protects the main chain from hydrolysis and oxidation, improves the compatibility of the silicone oil with organic matter, and reduces the dielectric constant of the silicone oil, preventing charge accumulation during operation and eliminating safety hazards. A common method for introducing alkyl groups into organosilicon segments is to first prepare hydrogen-containing siloxanes with different degrees of polymerization and hydrogen content using a strong acid catalyst, and then obtain the final product through an addition reaction between the hydrogen-containing siloxane monomer and an olefin. Patent CN11177996A describes the preparation of an organosilicon coolant containing a phase change component. It involves preparing hydrogen-containing siloxanes via trifluoromethanesulfonic acid catalysis, followed by an addition reaction with α-olefins to improve the compatibility of polysiloxanes with fluorocarbon compounds. However, the trifluoromethanesulfonic acid catalyst used requires immediate neutralization and quenching with calcium carbonate and filtration after the reaction, and the highly corrosive catalyst places higher demands on equipment and personnel. The invention patent with publication number CN 116438502A describes the preparation of an alkylmethylsiloxane coolant. Different molecular weight siloxanes are obtained through the addition of silanes to olefins via silane-hydrogen bonds. However, the invention has the following two problems: ① When the number of Si-H bonds increases, the number of alkyl groups added to the side chains also increases, leading to a rapid increase in product viscosity, reduced heat transfer efficiency, and increased power costs. Simultaneously, as the reaction proceeds, steric hindrance increases, making the addition reaction difficult. Furthermore, during the subsequent removal of low-boiling points, Si-H bonds decompose to produce H2, posing a safety hazard. ② To ensure a sufficiently low Si-H bond content in the product, an excess of olefins is usually added during the reaction. However, when the molecular weight of the olefins is too large, separation from the product is difficult, and olefins mixed into the product are easily oxidized over long periods of operation.

[0004] How to improve the defects of existing organosilicon compound coolants is a technical problem in this field. Summary of the Invention

[0005] In order to address the above-mentioned technical problems and overcome the shortcomings of existing coolants, this invention provides a silicon-based coolant, its preparation method, and its application.

[0006] This invention includes the following technical solutions:

[0007] On one hand, the present invention provides a silicon-based coolant having the following chemical structure: R1(R2)2SiO-[(CH3)2SiO] m -Si(R3)2R4, where: R1 and R4 are alkyl groups with 8 or more carbon atoms but less than or equal to 14, R2 and R3 are methyl, ethyl or isopropyl, and 6≤m<14.

[0008] The silicon-based coolant of this invention possesses both a high flash point and low viscosity, with a viscosity <35 mm. 2 / s, flash point >240℃, viscosity change before and after high-temperature storage <0.5mm 2 / s, pH change <0.2.

[0009] Furthermore, the coolant is prepared from methylcyclosiloxane, difunctional hydrogen-containing alkylsiloxane end-capping agent, and C8-C14 olefin.

[0010] Furthermore, the general formula of the methylcyclosiloxane is [(CH3)2SiO]. n Where 4 ≤ n ≤ 7. Specifically, the methylcyclosiloxane is any one or more of octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecylcyclohexasiloxane, and tetradecylcycloheptasiloxane.

[0011] Furthermore, the molar ratio of the methylcyclosiloxane to the difunctional hydrogen-containing alkylsiloxane end-capping agent is A, satisfying 6 ≤ A × n < 14.

[0012] Furthermore, the molar ratio B of the C8-C14 olefin and the difunctional hydrogen-containing alkylsiloxane end-capping agent satisfies 2 < B ≤ 2.6. The slight excess of olefin improves the stability of the coolant.

[0013] Furthermore, the difunctional hydrogen-containing alkylsiloxane end-capping agent is any one of 1,1,3,3-tetramethyldisiloxane, 1,1,3,3-tetraethyldisiloxane, and 1,1,3,3-tetraisopropyldisiloxane. Preferably, the difunctional hydrogen-containing alkylsiloxane end-capping agent is 1,1,3,3-tetramethyldisiloxane.

[0014] Specifically, the difunctionality mentioned in this invention refers to the presence of two functional groups in each of the hydrogen-containing alkylsiloxane end-capping agents that can react with silicon atoms in alkyl silicone oil. For example, 1,1,3,3-tetramethyldisiloxane, 1,1,3,3-tetraethyldisiloxane, and 1,1,3,3-tetraisopropyldisiloxane each contain two siloxane bonds that can react with silicon atoms in methylcyclosiloxanes. Similarly, the trifunctional end-capping agent mentioned in this invention contains three siloxane bonds that can react with silicon atoms in silicone oil, and the tetrafunctional end-capping agent contains four siloxane bonds that can react with silicon atoms in silicone oil.

[0015] Methylepoxysilanes undergo ring-opening polymerization under acid or base catalysis to yield chain polymers with larger molecular weights. In the polymerization of organosilicones, difunctional hydrogen-containing alkylsiloxanes act as end-capping agents, reacting with both ends of the polymer chain to prevent further chain growth. This results in organosilicon polymers with specific molecular weights and functional groups, allowing for precise control of polymer properties such as viscosity, mechanical properties, and thermal stability to meet the needs of specific applications.

[0016] This invention uses a difunctional hydrogen-containing alkylsiloxane as a capping agent. Compared to multifunctional capping agents, the reaction is easier to control, avoiding high cross-linking and gelation. The use of multifunctional capping agents easily leads to uncontrollable products. The difunctional hydrogen-containing alkylsiloxane capping agent of this invention can control the molecular weight and introduce Si-H bonds. Compared to difunctional capping agents, monofunctional capping agents can only cap one end of long-chain alkyl silicone oil, leaving the other end uncapped. The silicone oil molecules will continue to polymerize and grow. In other words, the monofunctional capping agent in this invention does not achieve the capping effect and cannot accurately control the molecular weight of the product.

[0017] On the other hand, the present invention provides a method for preparing the above-mentioned silicon-based coolant, comprising the following steps:

[0018] (1) Under an inert gas atmosphere, methylcyclosiloxane, difunctional hydrogen-containing alkylsiloxane end-capping agent and first catalyst are mixed and reacted. After the reaction is completed, the first catalyst is separated to obtain the intermediate product.

[0019] (2) The second catalyst and C8-C14 olefins were mixed and added dropwise to the intermediate product to react and obtain the crude product;

[0020] (3) The crude product is distilled under reduced pressure to obtain the product.

[0021] In the preparation method of this invention, a ring-opening polymerization reaction is first carried out using a methylcyclosiloxane and a difunctional hydrogen-containing alkylsiloxane end-capping agent to prepare a hydrogen-terminated siloxane. After filtering to remove the first catalyst, the siloxane undergoes an addition reaction with an olefin under the catalysis of a second catalyst. The resulting crude product is then subjected to vacuum distillation to remove low-boiling products, thus obtaining the final product. The coolant obtained by the preparation method of this invention has low impurity content, good compatibility with organic matter, and the low-boiling products can be reused as reactants during the production process, resulting in high economic benefits and greater environmental friendliness. Furthermore, the reaction is thorough, and no hydrogen is generated during post-processing, ensuring high safety.

[0022] Furthermore, in step (1), the reaction is first carried out at a temperature of 55-65℃ for 1.5-2.5h, and then at a temperature of 85-95℃ for 4-6h.

[0023] In step (2), the reaction temperature is 65-75℃ and the reaction time is 4.5-5.5h;

[0024] In step (3), the crude product is distilled at 150-180℃ for 0.5-1h.

[0025] Furthermore, the first catalyst is a sulfonic acid resin, and the second catalyst is a cassette catalyst.

[0026] In the preparation method of the present invention, the reaction in step (1) is divided into two stages. The reaction temperature in the first stage is 55-65℃ and the reaction time is 1.5-2.5h. The reaction temperature in the second stage is 85-95℃ and the reaction time is 4-6h. Since the ring-opening rate of solid acid catalysis is not as fast as that of homogeneous catalyst, it is necessary to extend the reaction time and increase the reaction temperature to improve the yield of the product.

[0027] Because some difunctional hydrogen-containing alkylsiloxane end-capping agents have low boiling points, the reaction temperature in the first stage should not be too high. The reaction temperature should be increased after the hydrogen-containing end-capping agent has partially ended the reaction to promote ring opening. However, if the temperature is too high, the product viscosity will be too high. If the reaction time is too short, the reaction will be incomplete. If the reaction time is too long, the reaction will have reached equilibrium and the product composition will not change significantly.

[0028] In step (2), the reaction temperature is 65-75℃ and the time is 4.5-5.5h. If the temperature is too low, the polymerization reaction will not be complete. If the temperature is too high, the viscosity of the condensation product will increase rapidly. If the time is too short, the reaction will not be complete. If the time is too long, the reaction will reach equilibrium and the composition of the product will not change significantly.

[0029] In step (3), the crude product is distilled at 150-180℃ for 0.5-1h. The distillation temperature and time affect the flash point of the product. If the temperature is too low and the time is too short, the low-boiling substances will not be completely removed. If the temperature is too high and the time is too long, the product performance will not be significantly affected, and energy will be wasted.

[0030] In another aspect, the present invention also provides the application of the above-mentioned silicon-based coolant or the silicon-based coolant prepared by the above-mentioned preparation method in semiconductor processing and data center server temperature control devices.

[0031] The silicon-based coolant of this invention possesses both a high flash point and low viscosity; when the flash point is >240°C, the viscosity is <35 mmHg. 2 / s, exhibiting good physical and chemical stability; the coolant preparation method of the present invention ensures thorough reaction, with no hydrogen generation in post-processing, and high safety. Attached Figure Description

[0032] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 The infrared spectrum of the coolant in Example 7;

[0034] Figure 2 The image shows the infrared spectrum of the coolant in Comparative Example 1. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention.

[0036] The raw materials used in each embodiment are shown in Table 1.

[0037] Table 1

[0038]

[0039] Example 1

[0040] This embodiment provides a silicon-based coolant with the following chemical structure: C8H 17 (CH3)2SiO-[(CH3)2SiO)]6-Si(CH3)2C8H 17 Its preparation method is as follows:

[0041] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h. Then, the temperature was raised to 85°C and the reaction was stirred for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.25 g of the second catalyst, castor catalyst, was mixed with 123.4 g (1.1 mol) of 1-octene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0042] Example 2

[0043] This embodiment provides a silicon-based coolant having the following chemical structure: C 11 H 23 (CH3)2SiO-[(CH3)2SiO)]6-Si(CH3)2C 11 H 23 Its preparation method is as follows:

[0044] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 222.5 g (0.5 mol) of dodecylcyclohexasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h. Then, the temperature was raised to 85°C and the reaction was stirred for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.27 g of the second catalyst, cassiterite, was mixed with 169.7 g (1.1 mol) of 1-undecene and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 170°C for 0.5 h to obtain the final product.

[0045] Example 3

[0046] This embodiment provides a silicon-based coolant having the following chemical structure: C 14 H 29 (CH3)2SiO-[(CH3)2SiO)]6-Si(CH3)2C 14 H 29 Its preparation method is as follows:

[0047] At 25°C, under nitrogen purging, 8.7 g of the first catalyst sulfonic acid resin, 92.7 g (0.25 mol) of decamethylcyclopentasiloxane, 129.8 g (0.25 mol) of tetradecylcycloheptasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h. Then, the temperature was raised to 85°C and the reaction was stirred for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.29 g of the second catalyst, cassiterite, was mixed with 216 g (1.1 mol) of 1-tetradecene and the temperature was raised to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 180°C for 1 h to obtain the final product.

[0048] Example 4

[0049] This embodiment provides a silicon-based coolant with the following chemical structure: C8H 17 (CH3)2SiO-[(CH3)2SiO)] 10 -Si(CH3)2C8H 17 Its preparation method is as follows:

[0050] At 25°C, purging with nitrogen, 7.8 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 40.3 g (0.3 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h. Then, the temperature was raised to 85°C and the reaction was stirred for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.21 g of the second catalyst, castor catalyst, and 74.1 g (0.66 mol) of 1-octene were mixed and heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0051] Example 5

[0052] This embodiment provides a silicon-based coolant with the following chemical structure: C8H 17 (CH3)2SiO-[(CH3)2SiO)]8-Si(CH3)2C 12 H 25 Its preparation method is as follows:

[0053] At 25°C, purging with nitrogen, 8.2 g of the first catalyst sulfonic acid resin, 237.3 g (0.64 mol) of decamethylcyclopentasiloxane, and 53.7 g (0.4 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.25 g of the second catalyst, castor catalyst, was mixed with a mixture of 58.3 g (0.52 mol) of 1-octene and 87.5 g (0.52 mol) of 1-dodecene. The mixture was heated to 75°C, and the intermediate product was added dropwise. The reaction was stirred for 5.5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0054] Example 6

[0055] This embodiment provides a silicon-based coolant with the following chemical structure: C9H 19 (CH3)2SiO-[(CH3)2SiO)]6-Si(CH3)2C9H 19 Its preparation method is as follows:

[0056] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 223.2 g (0.43 mol) of tetradecylcycloheptasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.25 g of the second catalyst, caster catalyst, was mixed with 132.3 g (1.05 mol) of 1-nonene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 4.5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0057] Example 7

[0058] This embodiment provides a silicon-based coolant with the following chemical structure: C9H 19 (CH3)2SiO-[(CH3)2SiO)]8-Si(CH3)2C9H 19 Its preparation method is as follows:

[0059] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 296.6 g (1.0 mol) of octamethylcyclotetrasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h. Then, the temperature was raised to 85°C and the reaction was stirred for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.27 g of the second catalyst, caster catalyst, was mixed with 113.4 g (0.9 mol) of 1-nonene and the temperature was raised to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0060] Example 8

[0061] This embodiment provides a silicon-based coolant with the following chemical structure: C9H 19 (CH3)2SiO-[(CH3)2SiO)]8-Si(CH3)2C9H 19 Its preparation method is as follows:

[0062] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 296.6 g (1.0 mol) of octamethylcyclotetrasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.31 g of the second catalyst, castor catalyst, was mixed with 170.1 g (1.35 mol) of 1-nonene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0063] Example 9

[0064] This embodiment provides a silicon-based coolant with the following chemical structure: C8H 17 (C2H5)2SiO-[(CH3)2SiO)]8-Si(C2H5)2C8H 17 Its preparation method is as follows:

[0065] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 296.6 g (1 mol) of octamethylcyclotetrasiloxane, and 95.2 g (0.5 mol) of 1,1,3,3-tetraethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 65°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.26 g of the second catalyst, castor catalyst, was mixed with 123.4 g (1.1 mol) of 1-octene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0066] Example 10

[0067] This embodiment provides a silicon-based coolant with the following chemical structure: C8H 17 [CH(CH3)2]2SiO-[(CH3)2SiO)]8-Si[CH(CH3)2]2C8H 17 Its preparation method is as follows:

[0068] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 296.6 g (1 mol) of octamethylcyclotetrasiloxane, and 123.3 g (0.5 mol) of 1,1,3,3-tetraisopropyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 65°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.26 g of the second catalyst, caster catalyst, was mixed with 123.4 g (1.1 mol) of 1-octene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0069] Comparative Example 1

[0070] This comparative example provides a silicon-based coolant having the following chemical structure: C 15 H 31 (CH3)2SiO-[(CH3)2SiO)]6-Si(CH3)2C 15 H 31 Its preparation method is as follows:

[0071] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 65°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.29 g of the second catalyst, cassiterite, was mixed with 231.4 g (1.1 mol) of 1-pentadene and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 180°C for 1 h to obtain the final product.

[0072] Comparative Example 2

[0073] This comparative example provides a silicon-based coolant having the following chemical structure: C 14 H 29 (CH3)2SiO-[(CH3)2SiO)]5-Si(CH3)2C 14 H 29 Its preparation method is as follows:

[0074] At 25°C, purging with nitrogen, 9.1 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 80.6 g (0.6 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 65°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.32 g of the second catalyst, cassiterite, was mixed with 259.2 g (1.32 mol) of 1-tetradecene and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 180°C for 1 h to obtain the final product.

[0075] Comparative Example 3

[0076] This comparative example provides a silicon-based coolant with the following chemical structure: C8H 17 (CH3)2SiO-[(CH3)2SiO)] 14 -Si(CH3)2C8H 17 Its preparation method is as follows:

[0077] At 25°C, purging with nitrogen, 7.5 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 28.2 g (0.21 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.17 g of the second catalyst, caster catalyst, and 51.6 g (0.46 mol) of 1-octene were mixed and heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 160°C for 0.5 h to obtain the final product.

[0078] Comparative Example 4

[0079] This comparative example provides a silicon-based coolant with the following chemical structure: C7H 15 (CH3)2SiO-[(CH3)2SiO)]6-Si(CH3)2C7H 15 Its preparation method is as follows:

[0080] At 25°C, purging with nitrogen, 8.7 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 67.1 g (0.5 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.22 g of the second catalyst, caster catalyst, was mixed with 107.8 g (1.1 mol) of 1-heptene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 180°C for 0.5 h to obtain the final product.

[0081] Comparative Example 5

[0082] This comparative example provides a silicon-based coolant with the following chemical structure: C8H 15 (CH3)2SiO-[(CH3)2SiO)] 14 -Si(CH3)2C8H 15 Its preparation method is as follows:

[0083] At 25°C, purging with nitrogen, 7.5 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 28.2 g (0.21 mol) of 1,1,3,3-tetramethyldisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.17 g of the second catalyst, castor catalyst, was mixed with 45.2 g (0.46 mol) of 1-octene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 150°C for 0.5 h to obtain the final product.

[0084] Comparative Example 6

[0085] This comparative example uses heptamethyltrisiloxane (molecular formula (CH3)3Si-O-Si(CH3)(H)-OSi(CH3)3), with a functionality of 3, as the end-capping agent. Specifically:

[0086] This comparative example provides a silicon-based coolant having the following chemical structure: (CH3)3SiO-(C8H 17 The preparation method of (CH3)Si-[(CH3)2SiO)]6-Si(CH3)3 is as follows:

[0087] At 25°C, purging with nitrogen, 7.5 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 111.3 g (0.5 mol) of 1,1,1,3,5,5,5-heptamethyltrisiloxane were added sequentially to a three-necked flask. The temperature was raised to 60°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.23 g of the second catalyst, castor catalyst, was mixed with 61.7 g (0.55 mol) of 1-octene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 150°C for 0.5 h to obtain the final product.

[0088] Comparative Example 7

[0089] This comparative example uses octamethyltetrasiloxane with a functionality of 4 as the end-capping agent. Specifically:

[0090] This comparative example provides a silicon-based coolant with the following chemical structure: C8H 15 (CH3)2SiO-[(CH3)2SiO)] 14 -Si(CH3)2C8H 15 Its preparation method is as follows:

[0091] At 25°C, purging with nitrogen, 7.5 g of the first catalyst sulfonic acid resin, 222.5 g (0.75 mol) of octamethylcyclotetrasiloxane, and 70.7 g (0.25 mol) of 1,1,3,3,5,5,7,7-octamethyltetrasiloxane were added sequentially to a three-necked flask. The temperature was raised to 65°C and the reaction was stirred for 2 h, followed by raising the temperature to 85°C and stirring for 5 h. After the reaction was completed, the first catalyst was separated by filtration to obtain the intermediate product. 0.21 g of the second catalyst, castor catalyst, was mixed with 61.7 g (0.55 mol) of 1-octene, and the mixture was heated to 75°C. The intermediate product was then added dropwise and the reaction was stirred for 5 h to obtain the crude product. The crude product was then distilled under reduced pressure at 150°C for 0.5 h to obtain the final product.

[0092] The coolants prepared in each embodiment and comparative example were subjected to kinematic viscosity, flash point, high-temperature storage viscosity test, pH value change, and olefin residue test. Specifically: kinematic viscosity was measured at 25°C using an Ubbelohde viscometer; flash point was measured using a fully automatic closed-cup flash point tester; high-temperature storage viscosity test involved sealing and storing the coolant at 180°C for 72 hours and then measuring the viscosity change at 25°C; pH value was measured using a pH meter; and the presence or absence of silane bonds and olefin residue was determined by the presence or absence of peaks in infrared spectroscopy.

[0093] Overall pass standard: Kinematic viscosity at 25℃ < 35 mm 2 / s, flash point >240℃, viscosity change at high temperature <0.5mm 2 / s, pH change <0.2.

[0094] The test results are shown in Table 2.

[0095] Table 2 Coolant Performance Test Data

[0096]

[0097]

[0098] As can be seen from the test results of Examples 1-10, the silicon-based coolant provided by the present invention, by defining the coolant structural formula R1(CH3)2SiO-[(CH3)2SiO], m -Si(CH3)2R2, where R1 and R2 are alkyl groups with 8 to 14 carbon atoms, 6 ≤ m < 14, giving it both a high flash point and low viscosity; the viscosity is < 35 mm when the flash point is > 240℃. 2 / s, and the coolant has good physical and chemical stability.

[0099] As can be seen from the test results of Examples 1 and 9-10, when different difunctional hydrogen-containing alkylsiloxanes are used as end-capping agents, the resulting coolant has good physicochemical properties under the premise of meeting other requirements of the present invention. This indicates that different difunctional hydrogen-containing alkylsiloxane end-capping agents are suitable as raw materials for the coolant of the present invention.

[0100] As can be seen from the test results of Examples 1 and 7-8, the coolant exhibits better stability when olefins are in slight excess. However, too little or too much olefin content can negatively impact the coolant's stability. Specifically, insufficient olefin addition leads to residual Si-H in the product, increasing the coolant's viscosity due to dehydrogenation crosslinking at high temperatures, and the released hydrogen may also pose safety hazards. The infrared spectrum of the coolant with insufficient olefin addition is shown below. Figure 1 As shown, 2154.9cm -1 and 906.23cm -1 The presence of unreacted Si-H bonds, which undergo dehydrogenation and crosslinking under platinum catalyst catalysis, leads to increased product viscosity. Adding excessive amounts of olefins, on the other hand, results in waste and increased costs.

[0101] The test results for Comparative Examples 1-7 were all unsatisfactory. Specifically, Comparative Example 1 failed the test primarily due to poor thermal stability, excessive viscosity changes during high-temperature storage, and the presence of residual olefins in the infrared test. Figure 2 As shown, at 1643cm -1 The presence of characteristic peaks for carbon-carbon double bonds is due to the boiling point of 1-pentadene reaching 268℃, making it difficult to remove completely. Residual olefins lead to decreased stability of the coolant; therefore, the number of carbon atoms in the reacting olefin should be less than 15. Comparative Example 2 failed the test primarily because of excessively low polymerization, resulting in poor viscosity and thermal stability; therefore, the degree of polymerization (m) should be greater than 5. Comparative Example 3 failed the test primarily because of excessively high polymerization, leading to excessively high viscosity; therefore, the degree of polymerization (m) should be less than 14. Comparative Example 4 failed the test primarily because the molecular weight of the olefin was too low, causing the coolant's flash point to be below standard; therefore, the number of carbon atoms in the reacting olefin should be greater than 7. Comparative Example 5 failed the test primarily because... The failure of Comparative Example 6 to meet the requirements for flash point and stability further demonstrates the influence of the number of carbon atoms and degree of polymerization of olefins on the performance of coolant. The failure of Comparative Example 6 to meet the requirements is mainly due to excessive viscosity and residual olefins in the product. The trifunctional end-capping agent 1,1,1,3,5,5,5-heptamethyltrisiloxane has one more active siloxane bond than the difunctional hydrogen-containing alkylsiloxane end-capping agent, resulting in a larger molecular weight. The increased molecular weight and viscosity of the product lead to incomplete reaction with olefins, resulting in residual olefins. A small amount of low molecular weight silicone oil has poor thermal stability and oxidizes and turns acidic during high-temperature storage. The failure of Comparative Example 7 to meet the requirements is mainly due to excessively high polymerization, which leads to excessively high product viscosity.

[0102] The present invention has been further described above with reference to specific embodiments. However, it should be understood that the specific description herein should not be construed as limiting the nature and scope of the present invention. Various modifications made to the above embodiments by those skilled in the art after reading this specification are all within the scope of protection of the present invention.

Claims

1. A silicon-based coolant, characterized in that, The coolant has the following chemical structure: R1(R2)2SiO-[(CH3)2SiO] m -Si(R3)2R4, where: R1 and R4 are alkyl groups with 8 or more carbon atoms but less than or equal to 14, R2 and R3 are methyl, ethyl or isopropyl, and 6≤m<14.

2. The silicon-based coolant according to claim 1, characterized in that, The coolant is prepared from methylcyclosiloxane, difunctional hydrogen-containing alkylsiloxane end-capping agent, and C8-C14 olefin.

3. The silicon-based coolant according to claim 2, characterized in that, The general formula of the methylcyclosiloxane is [(CH3)2SiO]. n , where 4≤n≤7.

4. The silicon-based coolant according to claim 3, characterized in that, The molar ratio of the methylcyclosiloxane to the difunctional hydrogen-containing alkylsiloxane end-capping agent is A, satisfying 6 ≤ A × n < 14.

5. The silicon-based coolant according to claim 2, characterized in that, The molar ratio of the C8-C14 olefin to the difunctional hydrogen-containing alkylsiloxane end-capping agent is B, satisfying 2 < B ≤ 2.

6.

6. The silicon-based coolant according to claim 2, characterized in that, The difunctional hydrogen-containing alkylsiloxane end-capping agent is any one of 1,1,3,3-tetramethyldisiloxane, 1,1,3,3-tetraethyldisiloxane, and 1,1,3,3-tetraisopropyldisiloxane.

7. The method for preparing the silicon-based coolant according to any one of claims 1-6, characterized in that, Includes the following steps: (1) Under an inert gas atmosphere, methylcyclosiloxane, difunctional hydrogen-containing alkylsiloxane end-capping agent and first catalyst are mixed and reacted. After the reaction is completed, the first catalyst is separated to obtain the intermediate product. (2) The second catalyst and C8-C14 olefins were mixed, and the intermediate product was added dropwise to react and obtain the crude product; (3) The crude product is distilled under reduced pressure to obtain the product.

8. The method for preparing the silicon-based coolant according to claim 7, characterized in that, In step (1), the reaction is first carried out at a temperature of 55-65℃ for 1.5-2.5h, and then at a temperature of 85-95℃ for 4-6h. In step (2), the reaction temperature is 65-75℃ and the reaction time is 4.5-5.5h; In step (3), the crude product is distilled at 150-180℃ for 0.5-1h.

9. The method for preparing the silicon-based coolant according to claim 7, characterized in that, The first catalyst is a sulfonic acid resin, and the second catalyst is a cassiterite catalyst.

10. The silicon-based coolant according to any one of claims 1-6 or the silicon-based coolant prepared by the preparation method according to any one of claims 7-9 is used in semiconductor processing and data center server temperature control devices.

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