High-performance insulating oil and preparation method thereof

Abstract

The invention discloses high-performance insulating oil and a preparation method thereof, and belongs to the technical field of preparation of electric insulating materials, and the preparation method comprises the following steps: purifying and drying oleic acid to obtain purified oleic acid; uniformly mixing the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution; the method comprises the following steps: carrying out laser induction on an oleic acid mixed solution by using nitrogen ions to vibrate oleic acid molecules to form isoheptadecanoic acid with different molecular structures, and after a reaction system is cooled, removing a reaction auxiliary agent in the isoheptadecanoic acid mixed solution to obtain pure isoheptadecanoic acid; isoheptadecanoic acid and trimethylolpropane (TMP) are subjected to an esterification reaction, and a reaction product is purified to obtain the synthetic ester insulating oil. The synthetic ester insulating oil prepared by the invention has the advantages of low viscosity, low pour point, high ignition point (greater than 300 DEG C) and high oxidation stability, and meets the application requirements of electrical equipment such as transformers and the like in extreme environments.

Description

Technical Field

[0001] The invention relates to high-performance insulating oil and a preparation method thereof, belonging to the technical field of preparation of electric insulating materials. Background Art

[0002] As the main dielectric insulating fluid for power equipment, mineral oil plays a vital role in insulation and heat dissipation. However, the source of the raw materials of the insulating fluid, the environmental impact and the safety risks have always been issues of concern to the power industry. At present, the international community generally regards mineral oil as the preferred material for insulating oil for power equipment. This practice not only aggravates the consumption of petroleum resources, but also, due to the poor natural degradation of mineral oil, once a leak occurs, it will cause long-term pollution to the environment. In addition, the flash point of mineral oil is relatively low, about 170°C, which significantly increases the risk of fire and explosion when a transformer fails. At present, natural ester insulating oil is easy to degrade compared to mineral oil, which reduces the impact on the environment and has higher fire safety. However, its disadvantages such as high viscosity, high pour point and low oxidation stability limit its continued application in industrial sites with harsh environments and high safety requirements. Summary of the invention

[0003] The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a high-performance insulating oil and a preparation method thereof. The prepared synthetic ester insulating oil has the advantages of low viscosity, low pour point, and high oxidation stability, meeting the application requirements of insulating oil in extreme environments.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0005] In a first aspect, the present invention provides a method for preparing high-performance insulating oil, comprising the following steps:

[0006] After oleic acid is purified and dried, purified oleic acid is obtained to reduce oleic acid C 18:1 Impurities in the system;

[0007] The purified oleic acid is uniformly mixed with a reaction aid to obtain an oleic acid mixed solution, thereby ensuring the stability of the reaction system;

[0008] The oleic acid mixture was laser-induced by nitrogen ions to make the oleic acid molecules vibrate. Laser parameters and reaction conditions, such as temperature, pressure and reaction time, are used to promote the formation of different isoheptadecanoic acids to obtain an isoheptadecanoic acid mixture, and after rapid cooling, the reaction aid in the isoheptadecanoic acid mixture is removed to obtain isoheptadecanoic acid;

[0009] Esterifying isoheptadecanoic acid with trimethylolpropane (TMP) to obtain a reaction product;

[0010] The product after the reaction is purified to obtain synthetic ester insulating oil.

[0011] Oleic acid drying treatment conditions: temperature is 50~60°C and pressure is 5~7 kPa.

[0012] The reaction aid is 4-6 wt% n-hexane.

[0013] The laser induction conditions are: wavelength 300-400 nm.

[0014] The laser energy density induced by the laser is 2~6 J / cm².

[0015] The laser-induced temperature was maintained at 25°C–100°C.

[0016] The laser-induced pressure was maintained between 1 and 10 atmospheres.

[0017] The conditions of the esterification reaction are as follows: reaction time 7-9 hours, reaction temperature 135-145° C., addition of 1.0-1.4 wt % p-toluenesulfonic acid catalyst, and a molar ratio of isoheptadecanoic acid to trimethylolpropane TMP of 3.08-3.12:1.

[0018] The purification conditions are as follows: the reaction product is stirred with ultrapure water at 55°C for 30 minutes and water and the final product are separated, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.15~0.4wt% of antioxidant is added and stirred for 2 hours at a temperature of 60~75°C and a vacuum degree of 2.5kpa. Finally, it is dehydrated in a vacuum dryer for 12~36 hours and then filtered.

[0019] In a second aspect, the present invention provides a high-performance insulating oil: prepared by the high-performance insulating oil preparation method.

[0020] Beneficial effects of the present invention: The present invention provides a high-performance insulating oil and a preparation method thereof, which uses laser induction technology to treat oleic acid (C 18:1 ) was modified to obtain isoheptadecanoic acid with different molecular structures, and directly esterified with TMP to successfully synthesize a high-performance synthetic ester insulating oil. Since TMP lacks a β-H functional group, the oxidative stability of the synthetic ester insulating oil of the present invention is significantly improved. At the same time, the introduction of isoheptadecanoic acid obtained after nitrogen ion laser induction makes the synthetic ester insulating oil have excellent properties such as a higher flash point (>300℃), a lower pour point and a lower kinematic viscosity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Oleic acid C 18:1 Molecular structure diagram of

[0022] Figure 2 The molecular structure diagram of isoheptadecanoic acid containing double bonds and different branching positions after laser induction of oleic acid according to the present invention;

[0023] Figure 3 It is a structural schematic diagram of the device for esterification reaction of the present invention;

[0024] Figure 4 This is a plasma instrument diagram of the laser irradiation system of the present invention;

[0025] Figure 5 This is a comparison chart of pour points of synthetic esters prepared by using octanoic acid, isooctanoic acid, nonanoic acid, decanoic acid, oleic acid and trimethylolpropane in the present invention;

[0026] Figure 6 This is a comparison chart of the viscosity of synthetic esters prepared by using octanoic acid, isooctanoic acid, nonanoic acid, decanoic acid, oleic acid and trimethylolpropane in the present invention;

[0027] Figure 7 This is a comparison chart of the ignition points of synthetic esters prepared by using octanoic acid, isooctanoic acid, nonanoic acid, decanoic acid, oleic acid and trimethylolpropane in the present invention. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the protection scope of the present invention.

[0029] Example 1

[0030] The present invention provides a method for synthesizing high-performance insulating oil, comprising the following steps:

[0031] Step 1: purify and dry oleic acid to obtain purified oleic acid to reduce oleic acid C 18:1 Impurities in the system. Oleic acid drying treatment conditions: temperature 50°C, pressure 7 kPa.

[0032] Step 2: Evenly mix the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution to ensure the stability of the reaction system. The reaction aid is 4 wt% of n-hexane.

[0033] Step 3: Use nitrogen ions to induce laser on the oleic acid mixture to make the oleic acid molecules vibrate. The structure of the laser irradiation system plasma instrument is as follows: Figure 4 As shown, The laser parameters and reaction conditions, such as temperature 30°C, pressure 1.5-2atm, continuous pulse mode reaction time 1-2min, wavelength 300-320nm, laser energy density 2-3J / cm², promote the formation of different isoheptadecanoic acids, obtain isoheptadecanoic acid mixture, and after rapid cooling, remove the reaction aid in the isoheptadecanoic acid mixture to obtain isoheptadecanoic acid.

[0034] Among them, C 18:1 Molecular structure Figure 1 As shown, under the above reaction conditions, C 18:1 The structure of isoheptadecanoic acid after N2⁺ laser induction is 2-Methyl-8-cis-heptadecene, and its molecular structure is as follows Figure 2 As shown in (a), 2 means the branch chain is located at the 2nd carbon atom, and 8 means the C=C double bond is located at the 8th carbon atom.

[0035] Step 4: esterify isoheptadecanoic acid with trimethylolpropane to obtain a reaction product. The esterification reaction device is as follows: Figure 3 As shown. Under the condition of temperature of 140℃, 2-Methyl-8-cis-heptadecene and TMP are in a molar ratio of 3.1:1, and 1.2wt% of p-toluenesulfonic acid is added as a catalyst. The reaction is placed in a reaction device equipped with a reflux condenser, a thermometer and a stirrer for 8 hours, and the reaction pressure is 5kPa. After the reaction is completed, the conversion rate of the product can be calculated by the following formula:

[0036]

[0037] In the formula, A vt A is the acid value of the reactant at time t; v0 is the acid value of the reactants at the initial moment; K is the acid-alcohol molar ratio.

[0038] Step five, purify the reaction product to obtain synthetic ester insulating oil. The reaction product is stirred at 55°C for 30 minutes with ultrapure water (resistance greater than 18.18MΩ·cm at 25°C) to separate water and the final product, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.2wt% of antioxidant (2,6-di-tert-butyl-4-methylphenol, tocopherol, mass ratio of 1:1.8) is added and stirred for 2h at a temperature of 60°C and a vacuum degree of 2.5kpa, and finally dehydrated and dried in a vacuum dryer for 12h and then filtered to obtain a synthetic ester insulating oil.

[0039] Table 1 Performance parameters of insulating oil prepared in Example 1 of the present invention

[0040]

[0041] Example 2

[0042] The present invention provides a method for synthesizing high-performance insulating oil, comprising the following steps:

[0043] Step 1: purify and dry oleic acid to obtain purified oleic acid to reduce oleic acid C 18:1 Impurities in the system. Oleic acid drying treatment conditions: temperature 55°C, pressure 6 kPa.

[0044] Step 2: Evenly mix the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution to ensure the stability of the reaction system. The reaction aid is 6 wt% of n-hexane.

[0045] Step 3: Use nitrogen ions to induce laser on the oleic acid mixture to make the oleic acid molecules vibrate. The structure of the laser irradiation system plasma instrument is as follows: Figure 4 As shown, The laser parameters and reaction conditions, such as temperature 50°C, pressure 2.5-3atm, continuous pulse mode reaction time 2.5min, wavelength 320-340nm, laser energy density 3-4J / cm², promote the formation of different isoheptadecanoic acids, obtain isoheptadecanoic acid mixture, and after rapid cooling, remove the reaction aid in the isoheptadecanoic acid mixture to obtain isoheptadecanoic acid.

[0046] Among them, C 18:1 Molecular structure Figure 1 As shown, under the above reaction conditions, C 18:1 The structure of isoheptadecanoic acid after N2⁺ laser induction is 3-Methyl-8-cis-heptadecene, and its molecular structure is as follows Figure 2 As shown in (b), 3 means the branch chain is located at the 3rd carbon atom, and 8 means the C=C double bond is located at the 8th C atom.

[0047] Step 4: esterify isoheptadecanoic acid with trimethylolpropane to obtain a reaction product. The esterification reaction device is as follows: Figure 3 As shown. Under the condition of temperature of 145℃, 2-Methyl-8-cis-heptadecene and TMP are in a molar ratio of 3.12:1, and 1.0wt% of p-toluenesulfonic acid is added as a catalyst. The reaction is placed in a reaction device equipped with a reflux condenser, a thermometer and a stirrer for 7 hours, and the reaction pressure is 5kPa. After the reaction is completed, the conversion rate of the product can be calculated by the following formula:

[0048]

[0049] In the formula, Avt A is the acid value of the reactant at time t; v0 is the acid value of the reactants at the initial moment; K is the acid-alcohol molar ratio.

[0050] Step five, purify the reaction product to obtain synthetic ester insulating oil. The reaction product is stirred at 55°C for 30 minutes with ultrapure water (resistance greater than 18.18MΩ•cm at 25°C) to separate water and the final product, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.3wt% of antioxidant (2,6-di-tert-butyl-4-methylphenol, tocopherol, mass ratio of 1:1.6) is added and stirred for 2h at a temperature of 65°C and a vacuum degree of 2.5kpa, and finally dehydrated and dried in a vacuum dryer for 24h and then filtered to obtain a synthetic ester insulating oil.

[0051] Table 2 Performance parameters of insulating oil prepared in Example 2 of the present invention

[0052]

[0053] Example 3

[0054] The present invention provides a method for synthesizing high-performance insulating oil, comprising the following steps:

[0055] Step 1: purify and dry oleic acid to obtain purified oleic acid to reduce oleic acid C 18:1 Impurities in the system. Oleic acid drying treatment conditions: temperature 60°C, pressure 5kPa.

[0056] Step 2: Evenly mix the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution to ensure the stability of the reaction system. The reaction aid is 4 wt% of n-hexane.

[0057] Step 3: Use nitrogen ions to induce laser on the oleic acid mixture to make the oleic acid molecules vibrate. The structure of the laser irradiation system plasma instrument is as follows: Figure 4 As shown, The laser parameters and reaction conditions, such as temperature 65 °C, pressure 4.5-5 atm, continuous pulse mode reaction time 3 min, wavelength 340-360 nm, laser energy density 4-5 J / cm², promote the formation of different isoheptadecanoic acids, obtain isoheptadecanoic acid mixture, and after rapid cooling, remove the reaction aid in the isoheptadecanoic acid mixture to obtain isoheptadecanoic acid.

[0058] Among them, C 18:1 Molecular structure Figure 1 As shown, under the above reaction conditions, C 18:1The structure of isoheptadecanoic acid after N2⁺ laser induction is 4-Methyl-8-cis-heptadecene. Figure 2 As shown in (c), 4 indicates that the branch chain is located at the 4th carbon atom, and 8 indicates that the C=C double bond is located at the 8th C atom.

[0059] Step 4: esterify isoheptadecanoic acid with trimethylolpropane to obtain a reaction product. The esterification reaction device is as follows: Figure 3 As shown. Under the condition of temperature of 135℃, 2-Methyl-8-cis-heptadecene and TMP are in a molar ratio of 3.08:1, and 1.4wt% of p-toluenesulfonic acid is added as a catalyst. The reaction is placed in a reaction device equipped with a reflux condenser, a thermometer and a stirrer for 9 hours, and the reaction pressure is 5kPa. After the reaction is completed, the conversion rate of the product can be calculated by the following formula:

[0060]

[0061] In the formula, A vt A is the acid value of the reactant at time t; v0 is the acid value of the reactants at the initial moment; K is the acid-alcohol molar ratio.

[0062] Step five, purify the reaction product to obtain synthetic ester insulating oil. The reaction product is stirred at 55°C for 30 minutes with ultrapure water (resistance greater than 18.18MΩ•cm at 25°C) to separate water and the final product, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.4wt% of antioxidant (2,6-di-tert-butyl-4-methylphenol, tocopherol, mass ratio of 1:1.4) is added and stirred for 2h at a temperature of 70°C and a vacuum degree of 2.5kpa, and finally dehydrated and dried in a vacuum dryer for 36h and then filtered to obtain a synthetic ester insulating oil.

[0063] Table 3 Performance parameters of insulating oil prepared in Example 3 of the present invention

[0064]

[0065] Example 4

[0066] The present invention provides a method for synthesizing high-performance insulating oil, comprising the following steps:

[0067] Step 1: purify and dry oleic acid to obtain purified oleic acid to reduce oleic acid C 18:1 Impurities in the system. Oleic acid drying treatment conditions: temperature 55°C, pressure 6 kPa.

[0068] Step 2: Evenly mix the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution to ensure the stability of the reaction system. The reaction aid is 4 wt% of n-hexane.

[0069] Step 3: Use nitrogen ions to induce laser on the oleic acid mixture to make the oleic acid molecules vibrate. The structure of the laser irradiation system plasma instrument is as follows: Figure 4 As shown, The laser parameters and reaction conditions, such as temperature 75 °C, pressure 6.5 atm, continuous pulse mode reaction time 4-5 min, wavelength 360-380 nm, laser energy density 5-6 J / cm², are used to promote the formation of different isoheptadecanoic acids, obtain an isoheptadecanoic acid mixture, and after rapid cooling, remove the reaction aid in the isoheptadecanoic acid mixture to obtain isoheptadecanoic acid.

[0070] Among them, C 18:1 Molecular structure Figure 1 As shown, under the above reaction conditions, C 18:1 The structure of isoheptadecanoic acid after N2⁺ laser induction is 5-Methyl-8-cis-heptadecene, and its molecular structure is as follows Figure 2 As shown in (d), 5 indicates that the branch chain is located at the 5th carbon atom, and 8 indicates that the C=C double bond is located at the 8th C atom.

[0071] Step 4: esterify isoheptadecanoic acid with trimethylolpropane to obtain a reaction product. The esterification reaction device is as follows: Figure 3 As shown. Under the condition of temperature of 140℃, 2-Methyl-8-cis-heptadecene and TMP are in a molar ratio of 3.1:1, and 1.2wt% of p-toluenesulfonic acid is added as a catalyst. The reaction is placed in a reaction device equipped with a reflux condenser, a thermometer and a stirrer for 8 hours, and the reaction pressure is 5kPa. After the reaction is completed, the conversion rate of the product can be calculated by the following formula:

[0072]

[0073] In the formula, A vt A is the acid value of the reactant at time t; v0 is the acid value of the reactants at the initial moment; K is the acid-alcohol molar ratio.

[0074] Step five, purify the reaction product to obtain synthetic ester insulating oil. The reaction product is stirred at 55°C for 30 minutes with ultrapure water (resistance greater than 18.18MΩ•cm at 25°C) to separate water and the final product, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.15wt% of antioxidant (2,6-di-tert-butyl-4-methylphenol, tocopherol, mass ratio of 1:1.3) is added and stirred for 2h at a temperature of 60°C and a vacuum degree of 2.5kpa, and finally dehydrated and dried in a vacuum dryer for 24h and then filtered to obtain a synthetic ester insulating oil.

[0075] Table 4 Performance parameters of insulating oil prepared in Example 4 of the present invention

[0076]

[0077] Example 5

[0078] The present invention provides a method for synthesizing high-performance insulating oil, comprising the following steps:

[0079] Step 1: purify and dry oleic acid to obtain purified oleic acid to reduce oleic acid C 18:1 Impurities in the system. Oleic acid drying treatment conditions: temperature 55°C, pressure 6 kPa.

[0080] Step 2: Evenly mix the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution to ensure the stability of the reaction system. The reaction aid is 4 wt% of n-hexane.

[0081] Step 3: Use nitrogen ions to induce laser on the oleic acid mixture to make the oleic acid molecules vibrate. The structure of the laser irradiation system plasma instrument is as follows: Figure 4 As shown, The laser parameters and reaction conditions, such as temperature of 80 °C, pressure of 6.5 atm, continuous pulse mode reaction time of 4-5 min, wavelength of 360-380 nm, laser energy density of 5-6 J / cm², promote the formation of different isoheptadecanoic acids, obtain an isoheptadecanoic acid mixture, and after rapid cooling, remove the reaction aid in the isoheptadecanoic acid mixture to obtain isoheptadecanoic acid.

[0082] Among them, C 18:1 Molecular structure Figure 1 As shown, under the above reaction conditions, C 18:1 The structure of isoheptadecanoic acid after N2⁺ laser induction is 6-Methyl-8-cis-heptadecene, and its molecular structure is as follows Figure 2As shown in (e), 6 indicates that the branch chain is located at the 6th carbon atom, and 8 indicates that the C=C double bond is located at the 8th C atom.

[0083] Step 4: esterify isoheptadecanoic acid with trimethylolpropane to obtain a reaction product. The esterification reaction device is as follows: Figure 3 As shown. Under the condition of temperature of 140℃, 2-Methyl-8-cis-heptadecene and TMP are in a molar ratio of 3.1:1, and 1.2wt% of p-toluenesulfonic acid is added as a catalyst. The reaction is placed in a reaction device equipped with a reflux condenser, a thermometer and a stirrer for 8 hours, and the reaction pressure is 5kPa. After the reaction is completed, the conversion rate of the product can be calculated by the following formula:

[0084]

[0085] In the formula, A vt A is the acid value of the reactant at time t; v0 is the acid value of the reactants at the initial moment; K is the acid-alcohol molar ratio.

[0086] Step five, purify the reaction product to obtain synthetic ester insulating oil. The reaction product is stirred at 55°C for 30 minutes with ultrapure water (resistance greater than 18.18MΩ•cm at 25°C) to separate water and the final product, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.15wt% of antioxidant (2,6-di-tert-butyl-4-methylphenol, tocopherol, mass ratio of 1:1.2) is added and stirred for 2h at a temperature of 60°C and a vacuum degree of 2.5kpa, and finally dehydrated and dried in a vacuum dryer for 24h and then filtered to obtain a synthetic ester insulating oil.

[0087] Table 5 Performance parameters of insulating oil prepared in Example 5 of the present invention

[0088]

[0089] In this study, fatty acids with different structures ( ) was esterified with TMP under the catalysis of p-toluenesulfonic acid. After the reaction, ester products with different structures were synthesized through a series of process optimization treatments (corresponding to . Then, The physical and chemical properties of synthetic esters were analyzed, and the effects of molecular structural factors such as double bonds (C=C), odd and even properties of fatty acid chains, branched structure and molecular weight on the pour point, flash point and viscosity of synthetic esters were studied.

[0090] The present invention has found that Figure 5As shown, in terms of pour point: the C=C double bond significantly reduces the pour point of the synthetic ester (from oleic acid C 18:1 The pour point of SE5 is -50℃, while stearic acid C without double bonds 18:0 The substance obtained by reaction with trimethylolpropane is solid at room temperature); compared with even-numbered carbonic acid, the presence of odd-numbered carbonic acid and branched structure increases the asymmetry of the molecule, making it more difficult to stack at low temperatures, resulting in a lower pour point (the pour point of SE2 is lower than that of SE1, proving that the branched structure can lower the pour point; the pour point of SE3 is lower than that of SE1, proving that odd-numbered carbonic acid can lower the pour point). Figure 6 As shown in Figure 2, in terms of viscosity: viscosity increases with increasing molecular weight (SE 1、 The viscosity of SE3, SE4 and SE5 increases in sequence). At the same molecular weight, the presence of the branched structure can reduce the viscosity (SE2 viscosity is less than SE1 viscosity). And from the comparison of the embodiments of the present application, it can be seen that the closer the branch is to the central carbon atom, the lower the viscosity. Figure 7 As shown in Figure 2, in terms of the ignition point, the ignition point increases with the increase of molecular weight. Based on these findings, the present invention adopts oleic acid C 18:1 As a raw material, it was cracked into isoheptadecane with a branched structure, unsaturated C=C bonds and odd carbons by laser induction, and then esterified with TMP to successfully synthesize a high-performance synthetic ester insulating oil. This method not only solves the problem of increased viscosity caused by high molecular weight, but also significantly improves the ignition point, making its fire safety level reach K level. In addition, due to the influence of factors such as C=C double bonds, odd carbons and branched structures, the pour point performance of the synthetic ester insulating oil of the present invention is significantly reduced, ensuring its safe use under various complex environmental conditions and meeting the performance requirements of transformer oil at different temperatures.

[0091] The synthetic ester insulating oil of the present invention has a flash point of up to 346°C, which is far higher than the index of K-grade (≥300°C) insulating liquid, greatly improving the fire safety of the power system; the pour point characteristic is as low as -53°C, which greatly improves the stability of operation in severe cold areas.

[0092] The above are only preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing high-performance insulating oil, characterized in that: The following steps are involved: After purifying and drying the oleic acid, purified oleic acid is obtained; uniformly mixing the purified oleic acid with a reaction aid to obtain an oleic acid mixed solution; Using nitrogen ions to induce laser vibration of oleic acid molecules in an oleic acid mixture to form isoheptadecanoic acid, thereby obtaining an isoheptadecanoic acid mixture; after cooling, removing a reaction aid from the isoheptadecanoic acid mixture to obtain isoheptadecanoic acid; Esterifying isoheptadecanoic acid with trimethylolpropane to obtain a reaction product; The product after the reaction is purified to obtain synthetic ester insulating oil.

2. The method for preparing high-performance insulating oil according to claim 1, characterized in that: Oleic acid drying treatment conditions: temperature is 50~60°C and pressure is 5~7 kPa.

3. The method for preparing high-performance insulating oil according to claim 1, characterized in that: The reaction aid is 4-6 wt% n-hexane.

4. The method for preparing high-performance insulating oil according to claim 1, characterized in that: The laser induction conditions are: wavelength 300~400 nm.

5. The method for preparing high-performance insulating oil according to claim 1, characterized in that: The laser energy density induced by the laser is 2~6 J / cm².

6. The method for preparing high performance insulating oil according to claim 1, characterized in that: The laser-induced temperature was maintained at 25°C–100°C.

7. The method for preparing high performance insulating oil according to claim 1, characterized in that: The laser-induced pressure was maintained between 1 and 10 atmospheres.

8. The method for preparing high-performance insulating oil according to claim 1, characterized in that: The conditions of the esterification reaction are as follows: reaction time 7-9 hours, reaction temperature 135-145° C., addition of 1.0-1.4 wt % p-toluenesulfonic acid catalyst, and a molar ratio of isoheptadecanoic acid to trimethylolpropane of 3.08-3.12:

1.

9. The method for preparing high performance insulating oil according to claim 1, characterized in that: The purification conditions are as follows: the reaction product is stirred with ultrapure water at 55°C for 30 minutes and water and the final product are separated, and the water washing operation is continued three times. After the water washing is completed, 4wt% of molecular sieves are added to absorb excess water. After the water is removed, 0.15~0.4wt% of antioxidant is added and stirred for 2 hours at a temperature of 60~75°C and a vacuum degree of 2.5kpa. Finally, it is dehydrated in a vacuum dryer for 12~36 hours and then filtered.

10. A high performance insulating oil, characterized in that: The high-performance insulating oil is prepared by the method for preparing the high-performance insulating oil according to any one of claims 1 to 9.

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