Perfluoroalkane dielectric cooling liquid composition with customizable performance and selective continuous preparation method thereof

Abstract

The invention belongs to the technical field of fine fluorine chemical industry, and discloses a perfluoroalkane dielectric cooling liquid composition with customizable performance and a selective continuous preparation method thereof. The composition is composed of saturated derivatives of hexafluoropropylene oligomer and can comprise a perfluoro-branched hexane isomer mixture, a perfluoro-branched nonane isomer mixture and a perfluoro-branched alkane higher oligomer mixture with the polymerization degree not lower than 7, and key performance such as the boiling range, the viscosity and the freezing point can be customized by regulating and controlling the proportion of all the components. According to the preparation method, an integrated continuous flow system is adopted, and on-demand production of cooling liquid with different component proportions is realized through the steps of controllable initial oligomerization, selectable controllable chain growth and continuous saturation. The product provided by the invention has excellent comprehensive thermophysical properties, is suitable for immersed cooling of high-heat-flux electronic equipment such as an AI data center and a super computer, and has the advantages of high process platformization degree and good economical efficiency.

Description

Technical Field

[0001] This invention belongs to the field of fine fluorochemical technology, specifically relating to a customizable perfluoroalkane dielectric coolant composition and its selective continuous preparation method. Background Technology

[0002] With the rapid development of artificial intelligence (AI) technology, the power density of server chips in data centers is increasing dramatically, pushing traditional heat dissipation methods to their physical limits. Immersion phase change cooling technology is considered a key technology for solving future high-density heat dissipation problems.

[0003] An ideal immersion coolant needs to possess excellent dielectric insulation, chemical stability, a suitable boiling point, and low viscosity. Currently, some perfluoroalkane coolants are available on the market, such as perfluorononane, which is produced by saturating hexafluoropropylene trimer and has been applied in the coolant field.

[0004] The oligomerization of hexafluoropropylene (HFP) is key to the preparation of precursors for these coolants. However, current research focuses heavily on improving reaction selectivity to obtain high-purity single oligomers. For example, Chinese patent CN112830863A discloses a continuous and controllable preparation method, the core of which is to selectively prepare high-purity dimers (for the preparation of perfluorohexanone, etc.) or high-purity trimers (for the preparation of surfactants, etc.) by adjusting temperature, pressure, and residence time. Similarly, Chinese patent CN1944360A aims to achieve >95% trimer selectivity, while Chinese patent CN102503767A aims to achieve >95% dimer selectivity.

[0005] This process approach, aimed at "purification" and "high selectivity," treats mixtures of products with different degrees of polymerization as "impurities" that need to be separated and removed. However, the inventors have discovered that these pure, single-component products exhibit significant functional defects when used as high-performance immersion coolants: 1. High-purity dimer derivatives (perfluoro-branched hexane): Although they have low viscosity and low freezing point, their boiling point (about 58-60°C) is too low for many high-power data center applications, which means that the cooling system needs to operate at higher pressure, increasing equipment costs and escaping losses.

[0006] 2. High-purity trimer derivatives (perfluoro-branched nonane): Although the boiling point (about 101-103℃) is suitable, its freezing point is relatively high (about -30℃) and its viscosity is high, which limits its application in data centers with low-temperature start-up or high-latitude deployment and increases pumping energy consumption.

[0007] Existing technologies clearly state that the formation of oligomer mixtures should be avoided. This invention, however, proposes a completely opposite and inventive technical solution to these existing technologies. This invention is based on a surprising discovery: by intentionally and controllably preparing oligomer mixtures in specific proportions, a coolant composition with a synergistic effect can be obtained, whose overall thermophysical properties (especially low-temperature fluidity and viscosity) are superior to any single pure component, while also enabling precise control of the boiling temperature. Summary of the Invention

[0008] Therefore, the purpose of this invention is to provide a customizable perfluoroalkane dielectric coolant composition and a selective continuous preparation method thereof, which obtains a coolant composition with synergistic effects by intentionally and controllably preparing a mixture of oligomers in a specific ratio, whose comprehensive thermophysical properties are superior to any single pure component, and whose boiling temperature can be precisely controlled.

[0009] To achieve the aforementioned objectives, the technical solution adopted is as follows: A dielectric coolant composition comprising: Component A is a mixture of perfluoro-branched hexane isomers derived from various isomers of hexafluoropropylene dimer through a saturation reaction; Component B is a mixture of perfluoro-branched nonane isomers derived from various isomers of hexafluoropropylene trimer through a saturation reaction; The weight ratio of component A to component B is 20:80 to 80:20.

[0010] As a further improvement of the present invention, it also includes component C, which is a mixture of perfluoro-branched alkane advanced oligomers derived from various isomers of hexafluoropropylene advanced oligomers with a degree of polymerization of not less than 7 through a saturated reaction; wherein, the weight percentage of component C in the dielectric coolant composition is 5% to 50%.

[0011] As a further improvement of the present invention, the dielectric coolant composition has a boiling range of less than 5°C or between 10°C and 30°C at standard atmospheric pressure.

[0012] A method for selectively preparing dielectric coolant compositions, the method being operated in an integrated continuous flow system, comprising the following steps: S1. Controllable initial oligomerization step: The raw material hexafluoropropylene and the first catalyst system are subjected to oligomerization reaction in the first continuous flow reactor. By controlling the reaction parameters in the first continuous flow reactor, an olefin intermediate mixture containing hexafluoropropylene dimer and hexafluoropropylene trimer is continuously prepared. S2, Continuous saturation step: The obtained olefin intermediate mixture and the fluorinated saturant are introduced into a second continuous flow reactor filled with a second catalyst to carry out a catalytic saturation reaction to obtain the target product composition, which is a coolant mainly composed of dimer and trimer derivatives.

[0013] As a further improvement of the present invention, between step S1 and step S2, one or more controllable chain growth steps are included for preparing the dielectric coolant composition as described in claim 2, specifically: the olefin intermediate mixture flowing out of the previous step is reacted with additionally added hexafluoropropylene monomer and chain growth catalyst in one or more subsequent continuous flow reactors to generate a hexafluoropropylene advanced oligomer with a degree of polymerization of not less than 7, thereby obtaining an advanced oligomer mixture; wherein, in the feed of step S2, the olefin intermediate mixture is replaced with the advanced oligomer mixture produced in this step.

[0014] As a further improvement of the present invention, in step S1, the first continuous flow reactor is a microchannel reactor, and the reaction temperature in the first continuous flow reactor is controlled at 0-40°C and the pressure is controlled at 0.1-0.5MPa, so as to increase the proportion of hexafluoropropylene dimer.

[0015] As a further improvement of the present invention, in step S1, the reaction temperature in the first continuous flow reactor is controlled at 50-100°C and the pressure is controlled at 0.6-1.0 MPa to increase the proportion of hexafluoropropylene trimer, thereby regulating the ratio of component A to component B in the final product.

[0016] As a further improvement of the present invention, the chain growth catalyst is a supported catalyst, the active component of which is cesium fluoride, and the support is a mesoporous molecular sieve with a pore size of 5-15 nanometers.

[0017] As a further improvement of the present invention, the second catalyst in step S2 is a supported bimetallic fluorination catalyst, the active components of which are cobalt fluoride and nickel fluoride, and the support is fluorinated alumina with a high specific surface area.

[0018] As a further improvement of the present invention, the fluorine-containing saturant in step S2 is anhydrous hydrogen fluoride or fluorine gas diluted with an inert gas, and the reaction temperature is 150-300°C.

[0019] The beneficial effects of this invention are: 1. Highly customizable product performance: By selecting different process modes (such as oligomerization-saturation only, or oligomerization-chain growth-saturation) and finely adjusting the reaction parameters of each step, a series of coolant products with different boiling points, different boiling ranges, different viscosities and freezing point characteristics can be flexibly manufactured on the same production line to meet the diverse and personalized heat dissipation needs of different application scenarios such as AI data centers, supercomputers, and power electronics.

[0020] 2. Process Platformization and Flexibility: This invention provides an open and flexible manufacturing platform, rather than a fixed process for a single product. This platform can quickly respond to changes in downstream technology development and specific customer needs, enabling "on-demand customization" and rapid production switchover, thus enhancing technological adaptability and market competitiveness.

[0021] 3. Innovative Catalytic System: Addressing the two major technical challenges of controllable preparation of advanced oligomers and efficient and non-destructive saturation of olefins, this invention proposes a dedicated supported chain growth catalyst and a supported bimetallic fluorination saturation catalyst, which respectively achieve effective control of the molecular weight distribution of the product and highly selective saturation of olefin double bonds, providing key guarantees for the feasibility and efficiency of the core process.

[0022] 4. Process integration and economy: The key polymerization, controllable chain growth and fluorination saturation steps are seamlessly integrated into a continuous and closed process, which realizes the efficient utilization of raw materials and the optimized integration of energy, significantly improves production efficiency and atom economy, reduces losses and separation costs in intermediate links, and is conducive to large-scale and low-cost production. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0024] I. Catalyst Preparation (a) Oligomerization catalyst: Under nitrogen protection, 10 g of anhydrous cesium fluoride (CsF) and 30 g of 18-crown ether-6 were added to a container containing 1000 mL of anhydrous acetonitrile and stirred until completely dissolved to obtain the first catalyst system.

[0025] (b) Chain growth catalyst: 10g of anhydrous cesium fluoride was dissolved in methanol, and 100g of SBA-15 mesoporous silica molecular sieve with a pore size of 10nm was added. After impregnation and drying, the catalyst was activated at 200℃ under vacuum for 6 hours to obtain a supported chain growth catalyst.

[0026] (c) Saturated catalyst: 100g of high specific surface area γ-Al2O3 spheres were impregnated in 50mL of an aqueous solution containing 25g of Co(NO3)2·6H2O and 25g of Ni(NO3)2·6H2O. After drying, the saturated spheres were calcined at 500℃ for 4 hours. The calcined spheres were then placed in a tube furnace and fluorinated at 350℃ with a 20% F2 / N2 mixed gas for 5 hours to obtain a supported bimetallic fluorination catalyst.

[0027] II. Comparative Preparation Comparative Example 1: Preparation of high-purity perfluorononane (based on trimer) using existing technology This example simulates existing technologies (such as CN112830863A or CN1944360A) to prepare trimers with high selectivity.

[0028] The oligomerization catalyst prepared in step (a) was pumped into the first microchannel reactor at a flow rate of 10 mL / min and HFP at a flow rate of 15 g / min. In accordance with the teachings of CN112830863A, in order to obtain a highly selective trimer, the reaction temperature was controlled at 80 °C, the pressure was maintained at 0.9 MPa, and the residence time was approximately 120 seconds.

[0029] The collected olefin products were subjected to a saturated reaction using the saturated catalyst prepared in step (c).

[0030] Olefin product distribution (GC-MS): Dimer (C6): 3.1%; Trimer (C9): 96.4%; Higher oligomers (C12+): 0.5%.

[0031] Final coolant performance: see Table 1.

[0032] Comparative Example 2: Preparation of high-purity perfluoro-branched hexane (based on dimer) using existing technology This example simulates existing technologies (such as CN112830863A or CN102503767A) to prepare dimers with high selectivity.

[0033] The oligomerization catalyst prepared in step (a) was pumped into the first microchannel reactor at a flow rate of 12 mL / min and HFP at a flow rate of 20 g / min. In accordance with the teachings of CN112830863A, in order to obtain highly selective dimers, the reaction temperature was controlled at 30 °C, the pressure was maintained at 0.3 MPa, and the residence time was approximately 45 seconds.

[0034] The collected olefin products were subjected to a saturated reaction using the saturated catalyst prepared in step (c).

[0035] Olefin product distribution (GC-MS): Dimer (C6): 95.2%; Trimer (C9): 4.5%; Higher oligomers (C12+): 0.3%.

[0036] Final coolant performance: see Table 1.

[0037] III. Preparation of Examples Example 1: Preparation of a narrow boiling range, low viscosity C6 / C9 mixture coolant The objective of this embodiment is to prepare a coolant that possesses both a suitable boiling point and excellent low-temperature fluidity. The reaction conditions are intentionally set between Comparative Example 1 and Comparative Example 2 to obtain a synergistic mixture of C6 and C9.

[0038] The oligomerization catalyst prepared in step (a) was pumped into the first microchannel reactor at a flow rate of 10 mL / min and HFP at a flow rate of 15 g / min. The reaction temperature was controlled at 60 °C, the pressure was maintained at 0.7 MPa, and the residence time was approximately 80 seconds.

[0039] The collected olefin products were subjected to a saturated reaction using the saturated catalyst prepared in step (c).

[0040] Olefin product distribution (GC-MS): Dimer (C6): 41.5%; Trimer (C9): 58.0%; Higher oligomers (C12+): 0.5%.

[0041] Final coolant properties: C6 / C9 weight ratio 42:58, boiling range 85-90℃, freezing point -55℃, kinematic viscosity at 25℃ 0.62cSt.

[0042] Example 2: Preparation of C6-dominant narrow boiling range, ultra-low viscosity coolant The objective of this embodiment is to prepare a coolant with a slightly higher boiling point (compared to Comparative Example 2) while maintaining extremely low viscosity and freezing point.

[0043] The oligomerization catalyst prepared in step (a) was pumped into the first microchannel reactor at a flow rate of 11 mL / min and HFP at a flow rate of 18 g / min. The reaction temperature was controlled at 45 °C, the pressure was maintained at 0.5 MPa, and the residence time was approximately 60 seconds.

[0044] The collected olefin products were subjected to a saturated reaction using the saturated catalyst prepared in step (c).

[0045] Olefin product distribution (GC-MS): Dimer (C6): 72.1%; Trimer (C9): 27.5%; Higher oligomers (C12+): 0.4%.

[0046] Final coolant properties: C6 / C9 weight ratio 72:28, boiling range 72-77℃, freezing point <-65℃, kinematic viscosity at 25℃ 0.53cSt.

[0047] Table 1 Performance comparison of Examples 1 & 2 and Comparative Examples 1 & 2 Table 1 clearly demonstrates the synergistic effect and customizability of the present invention.

[0048] Synergistic effect: The freezing point (-30°C) and viscosity (0.81 cSt) of Comparative Example 1 (high-purity C9) were both unsatisfactory. By intentionally introducing 41.5% C6 component according to the present invention (Example 1), the freezing point was significantly reduced to -55°C (a reduction of 25°C), and the viscosity was also significantly reduced to 0.62 cSt (a reduction of nearly 25%). This demonstrates that the "mixture" of the present invention is superior to the "pure substance" pursued by the prior art in key performance aspects.

[0049] Customizability: The boiling point (58-60°C) of Comparative Example 2 (high-purity C6) was too low for many applications. By intentionally introducing 27.5% C9 component according to the present invention (Example 2), the boiling point was precisely controlled to a more favorable range of 72-77°C, while still maintaining an extremely low freezing point of <-65°C. This demonstrates the ability of the present invention's platform to customize the boiling point on demand to balance volatility and performance.

[0050] Example 3: Preparation of a wide-boiling-range coolant containing advanced oligomers The objective of this embodiment is to prepare a coolant with a wide boiling range, suitable for high-power servers with large power fluctuations.

[0051] 1. Initial oligomerization: C9-rich olefin intermediates (C9 selectivity > 96%) were prepared according to the conditions of Comparative Example 1 (80℃, 0.9MPa).

[0052] 2. Controlled chain growth: The lower product phase (rich in C9) from step 1 was pumped at a flow rate of 20 g / min, along with additional HFP gas (3 g / min), into a tubular packed bed reactor (third continuous flow reactor) filled with 100 g (B) chain growth catalyst. The reaction temperature was maintained at 100 °C.

[0053] 3. Continuous saturation: The effluent from step 2 is subjected to a saturation reaction via a saturated catalyst (C).

[0054] Olefin product distribution (GC-MS, after chain growth): C6: 2.8%; C9: 74.3%; C12: 10.1%; C15: 5.5%; C21+ (heptamers and above): 7.3%.

[0055] Final coolant properties: boiling range 90-115℃ (boiling range≈25℃), freezing point -35℃, kinematic viscosity at 25℃ 0.95cSt; olefin product distribution: C6 2.8%, C97 4.3%, C121 0.1%, C15 5.5%, C21+ 7.3%.

[0056] Example 4: Preparation of a full-range coolant for C6 / C9 / higher oligomers The objective of this embodiment is to prepare a full-range coolant with an extremely wide boiling range and an extremely low freezing point.

[0057] 1. Initial oligomerization: A C6 / C9 mixture (C6: 41.5%, C9: 58.0%) was prepared according to the conditions of Example 1 (60°C, 0.7 MPa).

[0058] 2. Controlled chain growth: The lower product phase (C6 / C9 mixture) from step 1, along with additional HFP gas (3 g / min), is pumped into a third continuous flow reactor filled with chain growth catalyst at a flow rate of 20 g / min. The reaction temperature is maintained at 100 °C.

[0059] 3. Continuous saturation: The effluent from step 2 is subjected to a saturated reaction via a saturated catalyst.

[0060] Olefin product distribution (GC-MS, after chain growth): C6: 35.2%; C9: 44.1%; C12-C15: 12.5%; C21+ (heptamers and above): 8.2%.

[0061] Final coolant properties: boiling range 80-125℃ (boiling range≈45℃), freezing point -52℃, kinematic viscosity at 25℃ 0.70cSt; olefin product distribution: C6 35.2%, C9 44.1%, C12-C15 12.5%, C21+ 8.2%.

[0062] Table 2 Performance comparison of Examples 3 and 4 with Comparative Example 1 Table 2 further highlights the flexibility of the platform of this invention.

[0063] Customizable functionality: Comparative Example 1 (existing technology) can only provide a single product with a boiling range of <1.5°C. This invention (Example 3), through a "chain growth" model, can provide products with a boiling range of up to 25°C, suitable for heat dissipation under variable power loads.

[0064] Performance Synergy: Example 4 demonstrates the full capabilities of the platform of this invention. By combining "C6 / C9 mixing" with "chain growth," a unique product was prepared that possesses both an extremely wide boiling range (80-125°C) and excellent low-temperature performance (freezing point -52°C, viscosity 0.70 cSt). The performance combination of this product (low freezing point, low viscosity, wide boiling range) is completely unattainable by existing technologies (Comparative Example 1).

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, component splitting or combination, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A dielectric coolant composition, characterized in that, include: Component A is a mixture of perfluoro-branched hexane isomers derived from various isomers of hexafluoropropylene dimer through a saturation reaction; Component B is a mixture of perfluoro-branched nonane isomers derived from various isomers of hexafluoropropylene trimer through a saturation reaction; The weight ratio of component A to component B is 20:80 to 80:

20.

2. The dielectric coolant composition according to claim 1, characterized in that, It also includes component C, which is a mixture of perfluoro-branched alkane advanced oligomers derived from various isomers of hexafluoropropylene advanced oligomers with a degree of polymerization of not less than 7 through a saturated reaction; wherein, the weight percentage of component C in the dielectric coolant composition is 5% to 50%.

3. A dielectric coolant composition according to claim 1 or 2, characterized in that: The dielectric coolant composition has a boiling range of less than 5°C or between 10°C and 30°C at standard atmospheric pressure.

4. A method for selectively preparing dielectric coolant compositions, characterized in that, This method operates within an integrated continuous flow system and includes the following steps: S1. Controllable initial oligomerization step: The raw material hexafluoropropylene and the first catalyst system are subjected to oligomerization reaction in the first continuous flow reactor. By controlling the reaction parameters in the first continuous flow reactor, an olefin intermediate mixture containing hexafluoropropylene dimer and hexafluoropropylene trimer is continuously prepared. S2, Continuous saturation step: The obtained olefin intermediate mixture and the fluorinated saturant are introduced into a second continuous flow reactor filled with a second catalyst to carry out a catalytic saturation reaction and obtain the target product composition.

5. A method for selectively preparing a dielectric coolant composition according to claim 4, characterized in that, Between step S1 and step S2, one or more controllable chain growth steps are included for preparing the dielectric coolant composition as described in claim 2, specifically: the olefin intermediate mixture flowing out of the previous step is reacted with additionally added hexafluoropropylene monomer and chain growth catalyst in one or more subsequent continuous flow reactors to generate a hexafluoropropylene advanced oligomer with a degree of polymerization of not less than 7, resulting in an advanced oligomer mixture; wherein, in the feed of step S2, the olefin intermediate mixture is replaced with the advanced oligomer mixture produced in this step.

6. A method for selectively preparing a dielectric coolant composition according to claim 4, characterized in that: In step S1, the first continuous flow reactor is a microchannel reactor, and the reaction temperature in the first continuous flow reactor is controlled at 0-40℃ and the pressure is controlled at 0.1-0.5MPa to increase the proportion of hexafluoropropylene dimer.

7. A method for selectively preparing a dielectric coolant composition according to claim 4, characterized in that, In step S1, the reaction temperature in the first continuous flow reactor is controlled at 50-100℃ and the pressure is controlled at 0.6-1.0MPa to increase the proportion of hexafluoropropylene trimer.

8. A method for selectively preparing a dielectric coolant composition according to claim 5, characterized in that, The chain growth catalyst is a supported catalyst, the active component of which is cesium fluoride, and the support is a mesoporous molecular sieve with a pore size of 5-15 nanometers.

9. A method for selectively preparing a dielectric coolant composition according to claim 4, characterized in that, The second catalyst in step S2 is a supported bimetallic fluorination catalyst, whose active components are cobalt fluoride and nickel fluoride, and whose support is fluorinated alumina with a high specific surface area.

10. A method for selectively preparing a dielectric coolant composition according to claim 4 or 5, characterized in that, The fluorine-containing saturant in step S2 is anhydrous hydrogen fluoride or fluorine gas diluted with an inert gas, and the reaction temperature is 150-300℃.

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