Preparation method and application of modified vegetable oil coolant

Abstract

The application discloses a preparation method and application of modified vegetable oil coolant, and belongs to the technical field of liquid cooling. The preparation method comprises the following steps: carrying out glycerolysis reaction on vegetable oil and glycerol under the action of a catalyst to obtain an intermediate product containing diglyceride and monoglyceride; after removing unreacted glycerol and moisture, mixing the intermediate product with an organic solvent and a short-chain fatty acid with 2-6 carbon atoms, and carrying out esterification reaction under the action of an acidic catalyst to obtain a modified vegetable oil crude product; and after post-treatment, the modified vegetable oil coolant is obtained. By introducing a short-chain fatty acid group, the present application effectively reduces the intermolecular force, improves the kinematic viscosity and low-temperature fluidity of the coolant, and meanwhile, the high heat conductivity, high flash point and biodegradable characteristics of the vegetable oil are retained. The product is suitable for a data center immersion liquid cooling system, and is helpful to improve the heat dissipation efficiency and reduce the system energy consumption.

Description

Technical Field

[0001] This invention relates to the field of liquid cooling technology, specifically to a method for preparing and applying a modified vegetable oil coolant. Background Technology

[0002] Immersion liquid cooling technology is a method of heat dissipation that completely immerses IT equipment in coolant. The coolant can directly contact the heat-generating components, and the heat is carried away from the system through liquid convection circulation. Compared with traditional air cooling technology, immersion liquid cooling technology has the advantages of large heat capacity, high heat exchange efficiency, low noise, and low energy consumption.

[0003] The rapid development of artificial intelligence has ignited a surge in demand for computing power, leading to an explosive growth in global data center computing power. In accordance with national policies on energy efficiency, green and efficient development is the guiding principle, and the "Data Center Energy Efficiency Improvement Plan" has been issued to guide data center construction. The Ministry of Industry and Information Technology (MIIT) requires that by the end of 2026, newly built large-scale data centers achieve a PUE of <1.15. The use of immersion liquid cooling solutions can reduce the PUE to near 1, which is currently the most effective solution for reducing data center energy consumption.

[0004] Existing coolants mainly include fluorinated fluids, hydrocarbon oils (synthetic hydrocarbons and mineral oils), silicone oils, synthetic esters, and natural esters. Fluorinated fluids are expensive, have low boiling points and are highly volatile, and are severely affected by environmental policies (PFAS restrictions), leading to restrictions on their production and use in many regions. Hydrocarbon oils have poor material compatibility, low flash points and ignition points, posing a risk of flammability and combustion. Silicone oils are prone to thermal expansion and have poor heat transfer performance; although non-toxic, they are not biodegradable and recycling is not environmentally friendly. Synthetic and natural esters, on the other hand, have high thermal conductivity (around 0.17 W / mK, far exceeding fluorinated fluids and silicone oils), superior fire resistance (open flash point > 300°C, far exceeding hydrocarbon oils), better environmental performance, are 100% biodegradable, cause no continuous pollution, and are easy to recycle. Natural esters are derived from renewable plant-based raw materials and are potential candidates for green and environmentally friendly immersion liquid cooling technology. However, their high kinematic viscosity affects flowability and thus the heat transfer effect of the coolant. Therefore, solving the key problem of kinematic viscosity is crucial for applying natural plant-based cooling oils to immersion liquid-cooled data center coolants. Summary of the Invention

[0005] This invention provides a method for preparing and applying modified vegetable oil coolant, aiming to solve the problem that natural vegetable oil coolants have high kinematic viscosity and poor low-temperature fluidity, which makes them unsuitable for use in data center immersion liquid cooling systems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a modified vegetable oil coolant, comprising the following steps: Vegetable oils and glycerol are subjected to glycerolysis in the presence of a transesterification catalyst to obtain an intermediate product containing diglycerides and monoglycerides. After separating and removing unreacted glycerol and water from the intermediate product, it is mixed with an organic solvent and short-chain fatty acids with 2-6 carbon atoms, and subjected to a dehydration esterification reaction under the action of an acidic catalyst to obtain modified crude vegetable oil. The modified crude vegetable oil is post-processed to obtain the modified vegetable oil coolant.

[0007] In some embodiments, the mass ratio of the vegetable oil, the glycerol, and the transesterification catalyst is 250:(50-65):1.

[0008] In some embodiments, the vegetable oil includes at least one of grade I soybean oil, rapeseed oil, and sunflower oil.

[0009] In some embodiments, the transesterification catalyst includes at least one of sodium hydroxide, sodium bisulfate, zinc chloride, p-toluenesulfonic acid, zinc oxide, and potassium hydroxide.

[0010] In some embodiments, the glycerolysis reaction is carried out at a temperature of 200-260°C for a time of 1-4 hours.

[0011] In some embodiments, the acidic catalyst includes at least one of p-toluenesulfonic acid and concentrated sulfuric acid.

[0012] In some embodiments, the short-chain fatty acid having 2-6 carbon atoms includes at least one of acetic acid, propionic acid, butyric acid, valeric acid, and hexanoic acid.

[0013] In some embodiments, the organic solvent includes petroleum ether.

[0014] In some embodiments, the amount of acidic catalyst added is 0.5-2 wt% of the mass of the intermediate product after separation and removal of unreacted glycerol and water.

[0015] In some embodiments, the temperature of the water separation esterification reaction is 60-80°C.

[0016] Secondly, the present invention provides a modified vegetable oil coolant, which is prepared by the preparation method described above.

[0017] Thirdly, the present invention provides an application of the modified vegetable oil coolant described above in a data center immersion liquid cooling system.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention exposes hydroxyl groups through glycerol hydrolysis and then modifies the vegetable oil molecule by esterification with short-chain fatty acids having 2-6 carbon atoms, replacing some of the long-chain fatty acids with short-chain acid radicals. This molecular structure modification weakens intermolecular forces, reducing the kinematic viscosity of the modified coolant by approximately 70% compared to the raw oil (down to about 10 mm² / s at 40°C). It maintains good fluidity, especially at low temperatures, solving the problem of high pumping resistance and low heat exchange efficiency caused by the excessive viscosity of natural vegetable oils, thus meeting the circulation requirements of immersion liquid cooling systems.

[0019] In addition, the modified coolant retains the high flash point characteristics of natural plant esters (closed-cup flash point remains above 220℃), which is far higher than that of traditional hydrocarbon oils, eliminating the flammability safety hazard; at the same time, the thermal conductivity is maintained above 0.15W / (m·k), which is better than fluorinated liquids and silicone oils, ensuring efficient heat dissipation of data center IT equipment and achieving a balance between low viscosity and high safety. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments 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.

[0021] Figure 1 This is a schematic diagram of the preparation process of the modified vegetable oil coolant provided in the embodiments of this application. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] Immersion liquid cooling technology is a new type of heat dissipation technology that completely immerses IT equipment in coolant to achieve heat dissipation. The coolant can directly adhere to the heat-generating components of the equipment, and the heat generated by the equipment is carried away from the cooling system through liquid convection circulation. Compared with traditional air cooling technology, this technology has significant advantages such as large heat capacity, high heat exchange efficiency, low operating noise, and lower energy consumption.

[0024] With the rapid development of the artificial intelligence industry and the continued explosive growth in market demand for computing power, the global data center computing power scale is experiencing rapid growth. Under the guidance of national policies on efficient energy utilization, green and efficient development has become the core development theme of the data center industry. The Ministry of Industry and Information Technology's "Data Center Energy Efficiency Improvement Plan" clearly outlines industry construction standards, requiring that the PUE value of newly built large-scale data centers be controlled below 1.15 by the end of 2026. Immersion liquid cooling solutions can reduce the PUE value of data centers to near 1, making it one of the optimal solutions for reducing data center energy consumption and improving energy efficiency.

[0025] Currently, the mainstream coolants on the market are mainly divided into five categories: fluorinated fluids, hydrocarbon oils (including synthetic hydrocarbons and mineral oils), silicone oils, synthetic esters, and natural esters. The performance and application shortcomings of each type of coolant differ significantly: fluorinated fluids have high procurement costs, low boiling points, and are highly volatile; they are also significantly affected by PFAS-related environmental control policies, and their production and use are currently restricted in many regions; hydrocarbon oils have poor compatibility with equipment materials, low flash points and ignition points, posing a safety hazard of flammability and combustion; while silicone oils are non-toxic and harmless, they have a high coefficient of thermal expansion, poor heat exchange performance, and are not biodegradable, resulting in insufficient environmental friendliness in recycling and disposal.

[0026] In comparison, synthetic and natural esters exhibit significant performance advantages. Both have a thermal conductivity of up to 0.17 W / mK, far exceeding that of fluorinated fluids and silicone oils. They also possess excellent fire resistance, with open-cup flash points exceeding 300°C, significantly surpassing hydrocarbon oils and offering a higher safety factor. From an environmental perspective, both types of ester coolants are 100% biodegradable, causing no continuous environmental pollution and facilitating recycling. Natural esters, in particular, are made from renewable plant materials, making them a superior candidate for green, low-carbon immersion liquid cooling fluids.

[0027] However, natural ester coolants have a significant drawback: their high kinematic viscosity directly affects liquid flow and thus weakens overall heat transfer performance. Therefore, overcoming the core challenge of high kinematic viscosity is a critical technical issue that the industry urgently needs to address in order to scale up the application of natural plant-based cooling oils in immersion liquid-cooled data centers.

[0028] In view of this, the present invention provides a method for preparing and applying a modified vegetable oil coolant, aiming to solve the problem that natural vegetable oil coolants have high kinematic viscosity and poor low-temperature fluidity, which is not conducive to their application in data center immersion liquid cooling systems.

[0029] Firstly, this invention provides a method for preparing a modified vegetable oil coolant. Through chemical modification, the long-chain fatty acid groups in the molecular structure of natural vegetable oil are partially replaced with carboxylic acid groups that have shorter molecular chains and smaller molecular weights. This structural modification effectively reduces intermolecular forces, thereby obtaining a modified vegetable oil coolant with good fluidity at low temperatures, solving the problem that the high viscosity of natural vegetable oil is unsuitable for immersion liquid cooling systems.

[0030] The specific modification reaction pathways and molecular structural changes are shown below:

[0031] Specifically, according to an embodiment of the present invention, see Figure 1 The preparation method includes the following steps: S100: Vegetable oil and glycerol are subjected to glycerolysis reaction under the action of transesterification catalyst to obtain an intermediate product containing diglyceride (DAG) and monoglyceride (MAG).

[0032] This step converts triglycerides (TAG) in vegetable oils into a mixture of diglycerides (DAG) and monoglycerides (MAG) containing free hydroxyl groups via glycerolysis. Since the hydroxyl groups in natural vegetable oil molecules are completely occupied by long-chain fatty acids and lack active sites for subsequent modification, this step exposes the hydroxyl groups by disrupting the original ester bond structure. This provides a reaction basis for the subsequent esterification grafting of short-chain fatty acids, making it possible to replace part of the long-chain fatty acid structure with short-chain anions. This reduces intermolecular forces at the molecular level, thereby lowering the kinematic viscosity of the coolant.

[0033] In some embodiments of the present invention, the mass ratio of the vegetable oil, the glycerol, and the transesterification catalyst is 250:(50-65):1. Under this ratio, the molar ratio of glycerol to vegetable oil is approximately 2:1 to 2.5:1, and the molar amount of catalyst is 1% to 2%.

[0034] In this application, "vegetable oil" refers to a natural mixture with triglycerides as the main component, wherein the mass content of triglycerides is usually not less than 95%, and the remainder consists of trace components such as free fatty acids, phospholipids, sterols and water.

[0035] In a preferred embodiment, the vegetable oil may be selected from at least one of first-grade soybean oil, rapeseed oil, and sunflower oil. These raw materials are widely available, low in cost, and their main component is triglycerides, making them suitable for industrial production.

[0036] In some embodiments of the present invention, the transesterification catalyst includes at least one selected from sodium hydroxide (NaOH), sodium bisulfate (NaHSO4), zinc chloride (ZnCl2), p-toluenesulfonic acid, zinc oxide (ZnO), and potassium hydroxide (KOH). These catalysts can all effectively catalyze the glycerol hydrolysis reaction, with basic catalysts exhibiting higher reactivity and acidic catalysts showing fewer side reactions.

[0037] In some embodiments of the present invention, the glycerolysis reaction is carried out at a temperature of 200-260°C for 1-4 hours. Limiting the reaction conditions to the above range ensures reaction efficiency while avoiding increased energy consumption and darkening of the product color due to excessively high temperature or long reaction time.

[0038] S200: After separating and removing unreacted glycerol and water from the intermediate product, it is mixed with an organic solvent and short-chain fatty acids with 2-6 carbon atoms, and subjected to a dehydration esterification reaction under the action of an acidic catalyst to obtain modified crude vegetable oil.

[0039] This step separates unreacted glycerol and water to prevent impurities from interfering with the subsequent esterification reaction equilibrium and product purity. Short-chain fatty acids with 2-6 carbon atoms react with exposed free hydroxyl groups in the intermediate product to introduce short-chain acid radicals into the glycerol backbone. This structural modification effectively reduces intermolecular forces, thereby lowering the kinematic viscosity of the coolant and improving its low-temperature fluidity, meeting the pumping performance requirements of immersion liquid cooling systems, while retaining the original thermal conductivity and fire-retardant properties of vegetable oils.

[0040] In some embodiments of the present invention, the amount of acidic catalyst added is 0.5-2 wt% of the mass of the intermediate product after separation and removal of unreacted glycerol and water. Limiting the amount to this range ensures catalytic efficiency while avoiding increased costs and post-processing burdens due to excessive catalyst.

[0041] In some embodiments of the present invention, the acidic catalyst includes at least one of p-toluenesulfonic acid and concentrated sulfuric acid. Both p-toluenesulfonic acid and concentrated sulfuric acid are strong protic acids with high esterification catalytic activity, which can significantly reduce the activation energy of the reaction and promote the rapid combination of free hydroxyl groups in the intermediate product with short-chain fatty acids.

[0042] In some embodiments of the present invention, the short-chain fatty acid having 2-6 carbon atoms includes at least one of acetic acid, propionic acid, butyric acid, valeric acid, and hexanoic acid. By selecting the aforementioned short-chain fatty acid having 2-6 carbon atoms as a small molecule acid (R1COOH), the short-chain acid anion can replace part of the long-chain fatty acid, thereby weakening intermolecular forces, reducing the kinematic viscosity of the coolant, and improving low-temperature fluidity.

[0043] In some embodiments of the present invention, the organic solvent includes petroleum ether. Petroleum ether, as a reaction medium, not only effectively dissolves intermediate products and promotes homogeneous reaction, but also forms a low-boiling-point azeotrope with water. During the water separation and reflux process, it carries away the water generated in the reaction, breaking the equilibrium limitation of the esterification reaction and improving the conversion rate.

[0044] In some embodiments of the present invention, the temperature of the water separation esterification reaction is 60-80°C. By limiting the reaction temperature within the above range, petroleum ether with a boiling range of 60-90°C can be refluxed under these conditions, thereby achieving water separation.

[0045] S300: The modified crude vegetable oil is post-processed to obtain the modified vegetable oil coolant.

[0046] This post-processing step can purify the crude modified vegetable oil to meet the requirements of immersion liquid cooling in data centers.

[0047] In some embodiments of the present invention, the post-processing steps include: subjecting the modified crude vegetable oil to neutralization washing, decolorization, desolventization, adsorption purification, additive compounding and drying treatment in sequence.

[0048] This post-processing step purifies the modified crude vegetable oil to meet the requirements of immersion liquid cooling in data centers. Specifically, neutralization washing removes residual acidic catalysts and free acids, eliminating potential corrosion hazards to equipment and ensuring high electrical insulation; decolorization adsorption removes oxidation products and pigments, improving the product's oxidation stability; the desolventizing process removes low-boiling-point organic solvents, avoiding flash point reduction and volatilization risks; the combination of antioxidants and anticoagulants further extends service life and optimizes low-temperature flow properties; and deep drying keeps moisture within a safe range, preventing moisture from causing a decrease in insulation performance or hydrolysis of ester bonds.

[0049] As an example, the adsorbent used in the adsorption purification is selected from at least one of kaolin, alkaline alumina, and magnesium silicate.

[0050] As an example, the additive is selected from at least one of antioxidants and anticoagulants.

[0051] Secondly, the present invention provides a modified vegetable oil coolant, which, according to an embodiment of this application, is prepared by the preparation method described above.

[0052] The modified vegetable oil coolant provided in this application is obtained by the above-mentioned preparation method. Due to the introduction of short-chain fatty acid groups into its molecular structure, it exhibits significantly reduced kinematic viscosity and excellent low-temperature fluidity, meeting the pumping requirements of immersion liquid cooling systems. Simultaneously, this product retains the high thermal conductivity and high flash point characteristics of natural plant esters, possessing reliable fire safety performance and heat exchange efficiency. Furthermore, the coolant undergoes deep purification, resulting in extremely low water and impurity content, excellent electrical insulation properties, and is derived from renewable plant-based raw materials, making it biodegradable and meeting the comprehensive application requirements of data centers for efficient, safe, and environmentally friendly cooling media.

[0053] Thirdly, the present invention provides an application of the modified vegetable oil coolant described above in a data center immersion liquid cooling system.

[0054] This application utilizes the modified vegetable oil coolant in a data center immersion liquid cooling system. Its significantly reduced kinematic viscosity improves low-temperature fluidity and reduces circulation pump resistance, thereby lowering system energy consumption and optimizing power efficiency (PUE). Simultaneously, this coolant retains the high flash point and high thermal conductivity of natural plant esters, eliminating the flammability hazards of hydrocarbon oils and the environmental pollution risks of fluorinated liquids while ensuring efficient heat dissipation. Furthermore, the deeply purified coolant exhibits excellent electrical insulation and material compatibility, meeting the stringent application standards of data centers for efficient, safe, and environmentally friendly heat dissipation media.

[0055] The technical solution provided by the present invention will be described in detail below with reference to the embodiments.

[0056] Unless otherwise specified, the raw materials used in the examples and comparative examples are commercially available analytical grade materials.

[0057] Example 1 Example 1 of this application provides a modified vegetable oil coolant VSC100-02, the preparation method of which includes the following steps: (1) Glycerol hydrolysis reaction: Weigh 50g of glycerol and 250g of first-grade soybean oil (the molar ratio of glycerol to soybean oil is about 2:1) into a 500 ml three-necked flask, add 1g of alkaline catalyst NaOH, wherein the mass ratio of soybean oil, glycerol and NaOH is 250:50:1, nitrogen gas is introduced throughout the process for protection, stirring is started, the temperature is slowly raised to 235℃, and the reaction time is kept at 2h to obtain an intermediate product containing diglyceride and monoglyceride.

[0058] (2) Esterification modification: Cool the reaction solution obtained in step (1) to 150°C, remove excess glycerol and water by vacuum distillation, and after complete cooling, add 1L of petroleum ether solvent (boiling range 60-90°C) to dissolve, wash away the alkaline catalyst with water until neutral, add 1g of p-toluenesulfonic acid catalyst and 100g of excess acetic acid, heat to 70°C, reflux water separation until no new water is produced, esterification is completed, and crude modified vegetable oil is obtained.

[0059] (3) Post-processing: Cool the crude product obtained in step (2) to room temperature, add sodium carbonate solution to neutralize p-toluenesulfonic acid and excess acetic acid, wash with water until neutral, then add 1g of activated carbon for adsorption and decolorization. When the reaction solvent changes from dark brown to light yellow or colorless, remove the petroleum ether solvent by vacuum distillation. Add 3g of basic alumina, heat to 65℃, and stir for 3h for adsorption. Add 0.1% antioxidant and anticoagulant to the filtered oil, keep stirring at 60℃ for 2h, and mix evenly. Vacuum dehydrate to below 50ppm at 70℃ to obtain modified vegetable oil coolant VSC100-02.

[0060] Example 2 This embodiment provides a modified vegetable oil coolant VRC100-03, the preparation method of which includes the following steps: (1) Glycerol hydrolysis reaction: Weigh 65g of glycerol and 250g of rapeseed oil (the molar ratio of glycerol to rapeseed oil is about 2.5:1) into a 500ml three-necked flask, add 1g of acidic catalyst p-toluenesulfonic acid, wherein the mass ratio of rapeseed oil, glycerol and p-toluenesulfonic acid is 250:65:1, nitrogen gas is introduced throughout the process for protection, stirring is started, the temperature is slowly raised to 235℃, and the reaction time is kept at this temperature for 2h to obtain an intermediate product containing diglyceride and monoglyceride.

[0061] (2) Esterification modification: Cool the reaction solution obtained in step (1) to 150°C, remove excess glycerol and water by vacuum distillation, and after complete cooling, add 1L of petroleum ether solvent (boiling range 60-90°C) to dissolve it. Use the residual p-toluenesulfonic acid as the esterification catalyst directly, add 100g of mixed short-chain fatty acids (the mass ratio of acetic acid to propionic acid is 4:6), heat to 70°C to carry out water separation and reflux reaction until no new water is produced. The esterification is completed and the modified crude vegetable oil is obtained.

[0062] (3) Post-processing: Cool the crude product obtained in step (2) to room temperature, add sodium carbonate solution to neutralize p-toluenesulfonic acid and excess acid, wash with water until neutral, then add 1g of activated carbon for adsorption and decolorization. When the reaction solvent changes from dark brown to light yellow or colorless, remove the petroleum ether solvent by vacuum distillation. Add 3g of basic alumina for one adsorption and 3g of magnesium silicate adsorbent (100-200 mesh) for another adsorption at 65℃ and stir for 3h. Add 0.1% antioxidant and anticoagulant to the filtered oil, keep stirring at 60℃ for 2h, and mix evenly. Dehydrate under vacuum at 70℃ to below 50ppm to obtain modified vegetable oil coolant VRC100-03.

[0063] Example 3 This embodiment provides a modified vegetable oil coolant VSC100-04, which differs from Example 1 in that: the glycerol hydrolysis reaction temperature is 200℃, the time is 1h, the amount of acidic catalyst added is 0.5wt% of the intermediate product mass, and the esterification reaction temperature is 60℃. Other steps and parameters are the same as in Example 1, resulting in the modified vegetable oil coolant VSC100-04.

[0064] Example 4 This embodiment provides a modified vegetable oil coolant VSC100-05, which differs from Example 1 in that: the glycerol hydrolysis reaction temperature is 250℃, the time is 4h, the amount of acidic catalyst added is 2wt% of the intermediate product mass, and the esterification reaction temperature is 80℃. Other steps and parameters are the same as in Example 1, resulting in the modified vegetable oil coolant VSC100-05.

[0065] Comparative Example 1 Compared with Example 1, the difference is that no modification treatment is performed, and Grade 1 soybean oil is used directly as the coolant to obtain the coolant.

[0066] Comparative Example 2 Compared with Example 1, the difference is that: no modification treatment is performed, and rapeseed oil is used directly as the coolant to obtain the coolant.

[0067] Comparative Example 3 Compared with Example 1, the difference is that the short-chain fatty acid is replaced with octanoic acid (8 carbon atoms), and the other steps and parameters are the same as in Example 1 to obtain the coolant.

[0068] Performance testing The performance of the coolant samples prepared in Examples 1-4 and Comparative Examples 1-3 was tested. The test items and corresponding standards are as follows: Kinematic viscosity: determined according to GB / T 265-1988 "Determination of kinematic viscosity and calculation of dynamic viscosity of petroleum products".

[0069] Thermal conductivity: determined according to ASTM D7896-19, "Standard Test Method for Determination of Thermal Conductivity, Thermal Diffusivity and Volumetric Heat Capacity of Engine Coolants and Related Fluids by Transient Hot-Wire Liquid Thermal Conductivity Method".

[0070] Closed-cup flash point: determined according to GB / T 261-2021 "Determination of flash point - Binsky-Martin closed-cup method".

[0071] The test results are shown in Table 1: Table 1 Performance Test Results

[0072] As shown in Table 1, compared to Comparative Examples 1-3, the kinematic viscosity of the coolant in Examples 1-4 was significantly reduced, but the closed-cup flash point also decreased accordingly, requiring a balance between the two. Meanwhile, the degree of transesterification directly affects the final oil performance, and octanoic acid with excessively long molecular chains inhibits kinematic viscosity.

[0073] In the description of this specification, the references to terms such as "one embodiment / mode," "some embodiments / modes," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment / mode or example is included in at least one embodiment / mode or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment / mode or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments / modes or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments / modes or examples described in this specification, as well as the features of different embodiments / modes or examples.

[0074] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, technology, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, technology, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, technology, article, or apparatus that includes said element. In this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise expressly specified.

[0075] The above description is merely a specific embodiment of the present invention, enabling those skilled in the art to understand or implement 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 present 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 of the invention herein.

Claims

1. A method for preparing a modified vegetable oil coolant, characterized in that, Includes the following steps: Vegetable oils and glycerol are subjected to glycerolysis in the presence of a transesterification catalyst to obtain an intermediate product containing diglycerides and monoglycerides. After separating and removing unreacted glycerol and water from the intermediate product, it is mixed with an organic solvent and short-chain fatty acids with 2-6 carbon atoms, and subjected to a dehydration esterification reaction under the action of an acidic catalyst to obtain modified crude vegetable oil. The modified crude vegetable oil is post-processed to obtain the modified vegetable oil coolant.

2. The preparation method according to claim 1, characterized in that, The mass ratio of the vegetable oil, the glycerol, and the transesterification catalyst is 250:(50-65):

1.

3. The preparation method according to claim 1, characterized in that, The vegetable oils include at least one of grade 1 soybean oil, rapeseed oil, and sunflower oil.

4. The preparation method according to claim 1, characterized in that, The transesterification catalyst includes at least one of sodium hydroxide, sodium bisulfate, zinc chloride, p-toluenesulfonic acid, zinc oxide, and potassium hydroxide.

5. The preparation method according to claim 1, characterized in that, The glycerolysis reaction is carried out at a temperature of 200-260℃ for 1-4 hours.

6. The preparation method according to claim 1, characterized in that, The acidic catalyst includes at least one of p-toluenesulfonic acid and concentrated sulfuric acid; and / or, The short-chain fatty acids having 2-6 carbon atoms include at least one of acetic acid, propionic acid, butyric acid, valeric acid, and hexanoic acid; and / or, The organic solvent includes petroleum ether.

7. The preparation method according to claim 1, characterized in that, The amount of acidic catalyst added is 0.5-2 wt% of the mass of the intermediate product after separating and removing unreacted glycerol and water.

8. The preparation method according to claim 1, characterized in that, The temperature of the dehydration esterification reaction is 60-80℃.

9. A modified vegetable oil coolant, characterized in that, It is prepared by the preparation method according to any one of claims 1-8.

10. The application of the modified vegetable oil coolant as described in claim 9 in a data center immersion liquid cooling system.

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