Fluorine-free trisiloxane compound, preparation method and application thereof

Abstract

The present application relates to a kind of fluorine-free trisiloxane compounds and its preparation method and application, belong to the field of organosilicon chemicals, especially it is a kind of compound that can be used in electronic thermal management field as insulating coolant.The compound of the present application is single pure fluorine-free molecule, structural formula is (CH3) 3Si-O-Si (CH3) (CH (CH3) CH2CH3) -O-Si (CH3) 3, with 3.4~3.6mm 2 / s (40 DEG C) low viscosity, ≥1×10 14 Ω·cm high insulation, closed flash point ≥180 DEG C high safety features and wide temperature range characteristics, does not contain PFAS class permanent compound, environmental protection compliance.Its preparation method with hexamethyl disiloxane, methyl hydrogen dichlorosilane is raw material and is prepared by hydrolysis condensation to obtain intermediate, then under the action of low dosage Karstedt catalyst, it occurs with mixed C4 olefin silicon hydrogen addition, by high vacuum rectification to obtain target product, cost is greatly reduced, process adaptation industrialization.The compound can be used in data center, AI server, energy storage system, power battery, industrial temperature control and general efficient heat transfer and heat dissipation system's immersion liquid cooling system as insulating coolant, material compatibility is excellent.

Description

Technical Field

[0001] This invention relates to the field of fine organosilicon chemicals and high-efficiency heat transfer and cooling technology, specifically to a fluorine-free trisiloxane compound and its preparation method and application. Background Technology

[0002] With the rapid development of artificial intelligence, supercomputing centers, and high-density data centers, the heat dissipation power of single racks continues to break through 100kW, gradually moving towards 200kW and 400kW. Some leading institutions have already conducted megawatt (MW) rack testing and verification. Traditional air-cooling methods can no longer meet the heat dissipation requirements of high-power chips, and immersion liquid cooling has become the core technology route for next-generation data center thermal management. The core component of immersion liquid cooling is an insulating coolant, which must simultaneously meet multiple requirements such as high insulation, low viscosity, high flash point, strong thermal stability, and environmental compliance. Similarly, in scenarios such as thermal runaway protection for fast-charging power batteries, high-power industrial frequency converters, and efficient heat dissipation of power semiconductors such as IGBTs, there is an increasingly urgent need for insulating cooling media with low viscosity, high flash point, high insulation, and environmental friendliness.

[0003] Currently, commercially available immersion liquid cooling media are mainly divided into three categories: The first category is fluorinated coolants. These media have excellent insulation and non-flammability, but they belong to the PFAS class of permanent compounds. They are subject to strict control under the EU REACH regulations, the US EPA and domestic environmental protection policies, posing a very high compliance risk. In addition, the raw material costs are high, making it difficult to popularize them on a large scale.

[0004] The second category consists of mineral oils and synthetic hydrocarbon oils. While these media are relatively inexpensive, they suffer from drawbacks such as high kinematic viscosity, high pump consumption, susceptibility to oxidation and acidification, short service life, and strong swelling of seals. Their insulation performance can only reach 10. 12 The Ω·cm level is insufficient to meet the heat dissipation and safety requirements of highly reliable electronic equipment.

[0005] The third category is traditional modified silicone oil media. Existing alkyl modified silicone oils often have problems such as complex molecular structure, high kinematic viscosity, high raw material cost, and large amount of precious metal catalysts used in the synthesis process. In addition, some long-chain alkyl silicone oils have high persistence in the natural environment and have potential environmental accumulation risks, making it difficult to balance performance, cost and environmental protection requirements.

[0006] Furthermore, existing synthesis processes for trisiloxane-based liquid cooling media mostly employ chloroplatinic acid catalysts. High catalyst dosages and residual chloride ions can easily reduce the dielectric insulation performance. Additionally, the use of high-purity monoolefins as raw materials further increases production costs. Currently, there is no fluorine-free, PFAS-free, single-molecule structure, low-cost, and high-performance trisiloxane-based immersion liquid cooling media that can simultaneously address the multiple pain points of existing technologies regarding environmental compliance, cost control, heat dissipation performance, and process adaptability. Summary of the Invention

[0007] To overcome the shortcomings of existing high-efficiency heat transfer immersion liquid cooling media, such as the environmental risks of PFAS, high cost, high viscosity, insufficient insulation, and poor economic efficiency of synthesis processes, the present invention aims to provide a fluorine-free, single-pure molecule, highly insulating, and low-viscosity 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane; simultaneously, it provides a preparation method that achieves a dual reduction in raw material and catalytic costs, and the process is suitable for industrial production; it also provides the application of this compound in the field of immersion liquid cooling to meet the safety requirements of various high-efficiency heat transfer and heat dissipation systems.

[0008] The compound provided by the present invention has the structural formula shown in formula (I): (CH3)3Si-O-Si(CH3)(CH(CH3)CH2CH3)-O-Si(CH3)3 The chemical name is 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane, and the compound is fluorine-free.

[0009] Preferably, the compound has a purity ≥99.5 wt% and a kinematic viscosity of 3.4–3.6 mm at 40°C. 2 / s, volume resistivity ≥1×10 14 Ω·cm, dielectric strength ≥23kV / 2.5mm, closed-cup flash point ≥180℃, pour point ≤-68℃, thermal conductivity ≥0.15W / (m·K).

[0010] The compound provided by this invention is used as an insulating coolant.

[0011] Preferably, the insulating coolant is used in immersion liquid cooling systems for data centers, AI computing servers, supercomputing centers, energy storage systems, power batteries, industrial temperature control, and general high-efficiency heat transfer and heat dissipation systems.

[0012] Preferably, the insulating coolant comes into direct contact with electronic components, structural parts, and equipment in various temperature control and heat dissipation systems.

[0013] The method for preparing the compound provided by the present invention includes the following steps: Step S1: Using hexamethyldisiloxane and methyldichlorosilane as raw materials, a hydrolysis-condensation reaction controlled by an ice-water bath was carried out to prepare 1,1,1,3,5,5,5-heptamethyltrisiloxane intermediate; Step S2: Under the action of Karstedt platinum catalyst, the intermediate is subjected to hydrosilylation reaction with a mixture of C4 olefins to obtain crude product; Step S3: The crude product is purified by high vacuum distillation to obtain 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane.

[0014] Preferably, in step S2, the mixed C4 olefin comprises one or more of 1-butene, cis-2-butene, and trans-2-butene, and the molar ratio of olefin to intermediate is 1.2 to 1.3:1.

[0015] Preferably, in step S2, the amount of platinum in the Karstedt catalyst is 1.5–2 ppm, the reaction temperature is 75–80 °C, the reaction pressure is 0.2–0.3 MPa, and the reaction time is 2–3 h.

[0016] Preferably, the distillation conditions in step S3 are: vacuum degree 1-5 mmHg, distillation temperature 115-125℃.

[0017] The immersion liquid cooling composition provided by the present invention includes the aforementioned 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane, and ≤0.1wt% of an antioxidant.

[0018] Preferably, the composition is free of fluorine and PFAS compounds, compatible with EPDM, FKM or PTFE seals, has a swelling rate of <3%, and is non-corrosive to copper, aluminum and stainless steel.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. Excellent environmental compliance. The compound of this invention has a single molecular structure and is completely fluorine-free. It does not contain any PFAS-type permanent organic pollutants and is not a persistent organic pollutant. It has low environmental persistence risk and complies with the environmental regulations of major economies around the world, such as the EU REACH, the US EPA, and China. This fundamentally avoids the strict regulatory risks faced by fluorinated liquids.

[0020] 2. Comprehensive and balanced thermal management performance. The compound in this invention simultaneously possesses a thermal management performance of 3.4–3.6 mm. 2 Low kinematic viscosity / s (40℃), ≥1×10 14 Its ultra-high volume resistivity of Ω·cm, high closed-cup flash point of ≥180℃, and low pour point of ≤-68℃ enable an extremely wide applicable temperature range. Its low viscosity significantly reduces the circulation pump consumption of liquid cooling systems, improving overall system energy efficiency; its ultra-high insulation performance ensures that electronic components in various temperature control and heat dissipation systems can be directly immersed for heat dissipation, greatly improving system operational safety; and its excellent thermal stability allows for a service life of over 10 years under normal operating conditions.

[0021] 3. Significantly reduced production costs. This invention uses mixed C4 olefins, a major byproduct of the petrochemical industry, instead of high-purity monoolefins as raw materials, significantly reducing raw material procurement costs. It also employs a low-dosage Karstedt platinum catalyst, precisely controlling the platinum metal content at the ppm level of 1.5–2 ppm, greatly reducing the cost of precious metal catalysis. The overall production cost is only 1 / 5 to 1 / 8 of that of existing mainstream fluorinated liquids, giving it strong market competitiveness after large-scale production.

[0022] 4. Strong adaptability to industrial production. The synthesis process in this invention uses conventional organosilicon chemical production equipment throughout, with mild reaction conditions and no need for extreme conditions such as high temperature and high pressure; the high vacuum distillation purification process is mature, the product yield is stable, and it is fully adaptable to the industrial mass production of existing chemical production lines. The project has low barriers to entry and is easy to expand production quickly.

[0023] 5. Excellent material compatibility. The liquid cooling composition of this invention does not corrode commonly used electronic metal materials such as copper, aluminum, and stainless steel, FR-4 type PCB substrates, or mainstream sealing components such as EPDM, FKM, and PTFE, and has a swelling rate of less than 3%. It can be directly applied to various existing immersion liquid cooling systems without the need for equipment modification or upgrades, significantly reducing system modification costs and application barriers. Detailed Implementation

[0024] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0025] In the description of this invention, the terms “first,” “second,” “third,” “fourth,” etc., (if present), are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms are interchangeable where appropriate so that embodiments of the invention described herein can be implemented in orders other than those described herein. Furthermore, the terms “comprising” and “having,” and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0026] In this embodiment of the invention, all raw materials used are commercially available industrial-grade conventional raw materials, and the testing methods used are conventional standard testing methods in the art. Unless otherwise specified, the reaction equipment is conventional stainless steel reaction equipment in the art, and the operating conditions are within the conventional range that can be adjusted by those skilled in the art according to actual conditions. Example 1

[0027] In this embodiment of the invention, the synthesis of 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane includes the following steps: Step 1: Preparation of the hydrogen-containing trisiloxane intermediate. 780 g of hexamethyldisiloxane was added to a reaction vessel, and nitrogen gas was introduced to replace the air inside the vessel. Stirring was started, and the temperature was lowered to 0–5 °C using an ice-water bath. Under controlled temperature conditions, 155 g of methyldichlorosilane was slowly added dropwise at a molar ratio of approximately 4:1. After the addition was complete, stirring was continued for 30 min. Subsequently, 54 g of deionized water was slowly added to initiate a hydrolysis-condensation reaction, and the reaction was carried out at 5–15 °C for 2 h. After the reaction was completed, the mixture was allowed to stand and separate into layers. The organic phase was washed with water until neutral, dried, and then distilled under reduced pressure to obtain the 1,1,1,3,5,5,5-heptamethyltrisiloxane intermediate.

[0028] Step 2: Hydrosilylation reaction. The above intermediate was added to a high-pressure reactor, purged with nitrogen, and Karstedt platinum catalyst (2% platinum content, 2 ppm platinum amount) was added. The temperature was raised to 75°C. A mixture of C4 olefins (containing 1-butene, cis-2-butene, and trans-2-butene) was slowly introduced, controlling the reaction pressure at 0.2–0.3 MPa. The reaction was maintained at 75–80°C for 2.5 hours, until the infrared detection reached 2150 cm⁻¹. -1 The absorption peak of the Si-H bond disappears, and the crude product is obtained.

[0029] Step 3: Distillation purification. After removing light components by vacuum distillation, the crude product is subjected to high-vacuum distillation (vacuum degree 1-5 mmHg, distillation temperature 115-125℃), and the target fraction is collected to obtain 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane.

[0030] Gas chromatography (GC) analysis showed that the product purity was ≥99.5 wt%. The kinematic viscosity of the product at 40°C was 3.5 mm. 2 / s, volume resistivity 1.2×10 14 The compound exhibits a flash point of 186℃ (closed cup), 208℃ (open cup), -69℃ (pour point), 24kV / 2.5mm dielectric strength, and 0.161W / (m·K). After repeated testing, the closed-cup flash point remained stable between 185 and 190℃, and the open-cup flash point between 205 and 215℃. Its dielectric strength (2.5mm spacing) ranged from 23 to 26kV, fully meeting the safety and insulation requirements of immersion liquid cooling systems. Example 2

[0031] The experiment was essentially the same as in Example 1, except for the amount of Karstedt catalyst used in step 2. Multiple comparative experiments were conducted with platinum dosages of 1.0 ppm, 1.5 ppm, 2.0 ppm, and 5.0 ppm.

[0032] The results showed that the conversion rate was ≥95% at 1.5–2.0 ppm, and the product was colorless and transparent; the conversion rate was about 85% at 1.0 ppm, and the reaction time needed to be extended; the conversion rate was not significantly improved at 5.0 ppm, but the cost increased. Example 3

[0033] The process was essentially the same as in Example 1, except that in step 2, the mixed C4 olefins were replaced with other olefin feedstocks. Results showed that using high-purity isobutylene resulted in a slightly higher conversion rate, but significantly increased feedstock costs; using mixed C5 olefins resulted in a slightly lower conversion rate, but required a longer reaction time. Considering both cost and conversion rate, mixed C4 olefins were the optimal choice.

[0034] The compound obtained in Example 1 was subjected to immersion tests with commonly used materials in electronic devices. The test conditions were: 85°C × 1000 hours. The results are as follows: Silicone rubber has a high swelling rate in this compound (approximately 15-20%), and is not recommended for use as a sealing material. Example 4

[0035] To the 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane prepared in Example 1, 0.05 wt% of a hindered phenolic antioxidant was added, stirred until homogeneous, and filtered to obtain an immersion liquid-cooled composition. Testing showed that the properties of this composition were essentially consistent with those of Example 1, and the acid value did not significantly increase after a thermal stability test (150℃ × 1000 h).

[0036] Comparative Example 1 The method of Example 1 was followed, but the Karstedt catalyst was replaced with chloroplatinic acid (platinum dosage 5 ppm), while all other conditions remained the same. Results showed that the product was pale yellow, and the volume resistivity decreased to approximately 8 × 10⁻⁶. 13 The insulation performance was slightly lower than that of Example 1, and the amount of platinum used was higher, which increased the catalytic cost.

[0037] Comparative Example 2 The method of Example 1 was followed, but the mixed C4 olefins were replaced with high-purity isobutylene (purity ≥99%), while all other conditions remained the same. The results showed that the product performance was basically the same as in Example 1, but the raw material cost increased by approximately 15-20%, resulting in poor economic efficiency.

[0038] Comparative Example 3 The compound obtained in Example 1 was compared with commercially available fluorinated coolants in terms of performance. The results showed that the compound in Example 1 had significantly better volume resistivity and dielectric strength than fluorinated coolants, a higher flash point, no risk of combustion, and a cost that was only about 1 / 5 to 1 / 8 of that of fluorinated coolants. Furthermore, it did not contain PFAS-type permanent compounds, thus posing no environmental compliance risks.

[0039] In the embodiments, the 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane and its compositions provided by the present invention can be widely used in data centers, AI computing servers, supercomputing centers, energy storage systems, power batteries, industrial temperature control and general high-efficiency heat transfer and heat dissipation systems, etc. It has excellent insulation, thermal conductivity and material compatibility, and is completely fluorine-free and free of PFAS compounds, which meets global environmental regulations. The synthesis process is mild and the cost is controllable. It can be directly applied to various existing high-efficiency heat transfer and heat dissipation systems without the need for large-scale equipment modification and upgrades, which significantly reduces the application threshold and overall cost, and has broad industrial application prospects.

[0040] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0041] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A compound, characterized in that, The structural formula is shown in equation (I): (CH3)3Si-O-Si(CH3)(CH(CH3)CH2CH3)-O-Si(CH3)3 Its chemical name is: 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane.

2. The compound according to claim 1, characterized in that, The compound has a purity ≥99.5 wt% and a kinematic viscosity of 3.4–3.6 mm at 40°C. 2 / s, volume resistivity ≥1×10 14 Ω·cm, dielectric strength ≥23kV / 2.5mm, closed-cup flash point ≥180℃, pour point ≤-68℃, thermal conductivity ≥0.15W / (m·K).

3. The use of the compound according to any one of claims 1 to 2 as an insulating coolant.

4. The application according to claim 3, characterized in that, The insulating coolant is used in immersion liquid cooling systems for data centers, AI computing servers, supercomputing centers, energy storage systems, power batteries, industrial temperature control, and general high-efficiency heat transfer and dissipation.

5. The application according to claim 3, characterized in that, The insulating coolant comes into direct contact with the server motherboard, CPU, GPU, power battery cells, power devices, or PCB components.

6. A method for preparing the compound according to claim 1, characterized in that, Includes the following steps: Step S1: Using hexamethyldisiloxane and methyldichlorosilane as raw materials, a hydrolysis-condensation reaction controlled by an ice-water bath was carried out to prepare 1,1,1,3,5,5,5-heptamethyltrisiloxane intermediate; Step S2: Under the action of Karstedt platinum catalyst, the intermediate is subjected to hydrosilylation reaction with a mixture of C4 olefins to obtain crude product; Step S3: The crude product is purified by high vacuum distillation to obtain 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane.

7. The preparation method according to claim 6, characterized in that, In step S2, the mixed C4 olefins include one or more of 1-butene, cis-2-butene, and trans-2-butene, and the molar ratio of olefins to intermediates is 1.2 to 1.3:

1.

8. The preparation method according to claim 6, characterized in that, In step S2, the amount of platinum in the Karstedt catalyst is 1.5–2 ppm, the reaction temperature is 75–80 °C, the reaction pressure is 0.2–0.3 MPa, and the reaction time is 2–3 h.

9. The preparation method according to claim 6, characterized in that, The distillation conditions in step S3 are: vacuum degree 1-5 mmHg, distillation temperature 115-125℃.

10. An immersion liquid cooling composition, characterized in that, It includes 3-sec-butyl-1,1,1,3,5,5,5-heptamethyltrisiloxane as described in claim 1, and ≤0.1wt% of an antioxidant.

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