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CN-121974801-A - Pentaerythritol mixed fatty acid ester, and preparation method and application thereof

CN121974801ACN 121974801 ACN121974801 ACN 121974801ACN-121974801-A

Abstract

The invention belongs to the technical field of pentaerythritol fatty acid ester synthesis, and particularly relates to pentaerythritol mixed fatty acid ester, a preparation method and application thereof. The method comprises the steps of mixing pentaerythritol, fatty acid, a catalyst and a water-carrying agent, carrying out esterification reaction to obtain an esterification reaction liquid, purifying the esterification reaction liquid to obtain pentaerythritol mixed fatty acid ester, wherein the fatty acid comprises n-heptanoic acid, n-octanoic acid and 3, 5-trimethylhexanoic acid, and the molar ratio of the n-heptanoic acid to the n-octanoic acid to the 3, 5-trimethylhexanoic acid is (1-8): 2. According to the invention, through reasonably selecting the acid raw material for esterification reaction to react with pentaerythritol and regulating and controlling the molar ratio of three fatty acids, the obtained pentaerythritol mixed fatty acid ester has the characteristics of low viscosity and high ignition point, so that the pentaerythritol mixed fatty acid ester has excellent low-temperature fluidity and high-temperature stability, and meanwhile, the pentaerythritol mixed fatty acid ester provided by the invention also has excellent electrical property.

Inventors

  • LOU WENJING
  • WANG YANAN
  • YU HONGYUAN
  • ZHAO QILONG
  • Su Huaigang

Assignees

  • 中国科学院兰州化学物理研究所

Dates

Publication Date
20260505
Application Date
20260129

Claims (10)

  1. 1. The preparation method of the pentaerythritol mixed fatty acid ester is characterized by comprising the following steps of: The method comprises the steps of mixing pentaerythritol, fatty acid, a catalyst and a water-carrying agent, carrying out esterification reaction to obtain an esterification reaction liquid, purifying the esterification reaction liquid to obtain pentaerythritol mixed fatty acid ester, wherein the fatty acid comprises n-heptanoic acid, n-octanoic acid and 3, 5-trimethylhexanoic acid, and the molar ratio of the n-heptanoic acid to the n-octanoic acid to the 3, 5-trimethylhexanoic acid is (1-8): 2.
  2. 2. The preparation method according to claim 1, wherein the molar ratio of the hydroxyl group of pentaerythritol to the carboxyl group of the fatty acid is 1:1-1.05.
  3. 3. The preparation method of the catalyst according to claim 1, wherein the catalyst is a tin-based catalyst, and the mass of the catalyst is 0.1-0.2% of the total mass of pentaerythritol and fatty acid.
  4. 4. A method of preparation according to claim 3 wherein the tin based catalyst is stannous oxalate.
  5. 5. The method of claim 1, wherein the water-carrying agent comprises one or more of toluene, xylene, and petroleum ether.
  6. 6. The method according to any one of claims 1 to 5, wherein the temperature of the esterification reaction is 180 to 200 ℃.
  7. 7. The preparation method of the catalyst according to claim 1, wherein the purification treatment comprises the steps of mixing the esterification reaction liquid with activated carbon, and then performing reduced pressure distillation, wherein the temperature of the reduced pressure distillation is 180-200 ℃, and the vacuum negative pressure is-0.05 to-0.09 MPa.
  8. 8. The pentaerythritol mixed fatty acid ester prepared by the preparation method according to any one of claims 1 to 7.
  9. 9. The pentaerythritol mixed fatty acid ester according to claim 8, wherein the kinematic viscosity of the pentaerythritol mixed fatty acid ester at 40 ℃ is less than 28.6mm 2 /s, and the ignition point is not less than 310 ℃.
  10. 10. Use of pentaerythritol mixed fatty acid esters according to claim 8 or 9 as base oil for synthetic ester insulating oils.

Description

Pentaerythritol mixed fatty acid ester, and preparation method and application thereof Technical Field The invention belongs to the technical field of pentaerythritol fatty acid ester synthesis, and particularly relates to pentaerythritol mixed fatty acid ester, a preparation method and application thereof. Background Insulating oils, also commonly referred to as transformer oils, are an extremely important class of liquid dielectrics. The high-voltage power supply is widely applied to large-scale power equipment such as power transformers, high-voltage bushings, circuit breakers, capacitors and the like, and is honored as 'blood' of the power equipment. Early insulating oils were directly refined from petroleum, primarily naphthenic mineral oils. The insulating oil is the most widely used insulating oil in the global scope due to low cost, stable performance and mature production process. However, mineral oils are flammable and poorly biodegradable, and once leaked, they are extremely prone to fire and cause serious environmental pollution. With the increasing demands of people for safety and environmental protection, the limitation of mineral oil is increasingly prominent. Ester insulating oils have gained wide acceptance as an excellent alternative to mineral oils. However, within the family of esters, there is a significant difference in performance between natural esters derived from vegetable oils and synthetic esters synthesized by chemistry. Although natural esters are attracting attention due to their excellent biodegradability and reproducibility, natural ester molecules are derived from vegetable oils, generally contain unsaturated double bonds, are easily oxidized, and contain long-chain fatty acids with poor low-temperature fluidity, and ester bonds of triglycerides are more easily hydrolyzed than synthetic esters. Therefore, in many application scenarios with stringent requirements on performance, the synthetic ester insulating oil exhibits its irreplaceable advantages, becoming a better choice. But the low-temperature fluidity and high-temperature stability of the current synthetic ester insulating oil are poor, further improvements are needed. Disclosure of Invention The invention aims to provide pentaerythritol mixed fatty acid ester, a preparation method and application thereof, and the pentaerythritol mixed fatty acid ester provided by the invention has the characteristics of low viscosity and high ignition point, so that the pentaerythritol mixed fatty acid ester has excellent low-temperature fluidity and high-temperature stability, and has wide application value as an ester insulating oil base oil. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a preparation method of pentaerythritol mixed fatty acid ester, which comprises the following steps: The method comprises the steps of mixing pentaerythritol, fatty acid, a catalyst and a water-carrying agent, carrying out esterification reaction to obtain an esterification reaction liquid, purifying the esterification reaction liquid to obtain pentaerythritol mixed fatty acid ester, wherein the fatty acid comprises n-heptanoic acid, n-octanoic acid and 3, 5-trimethylhexanoic acid, and the molar ratio of the n-heptanoic acid to the n-octanoic acid to the 3, 5-trimethylhexanoic acid is (1-8): 2. Preferably, the molar ratio of the hydroxyl group of the pentaerythritol to the carboxyl group of the fatty acid is 1:1-1.05. Preferably, the catalyst is a tin-based catalyst, and the mass of the catalyst accounts for 0.1-0.2% of the total mass of the pentaerythritol and the fatty acid. Preferably, the tin-based catalyst is stannous oxalate. Preferably, the water-carrying agent comprises one or more of toluene, xylene and petroleum ether. Preferably, the temperature of the esterification reaction is 180-200 ℃. Preferably, the purification treatment comprises the steps of mixing the esterification reaction liquid and the activated carbon, and then carrying out reduced pressure distillation, wherein the temperature of the reduced pressure distillation is 180-200 ℃, and the vacuum negative pressure is minus 0.05-minus 0.09MPa. The invention provides the pentaerythritol mixed fatty acid ester prepared by the preparation method. Preferably, the kinematic viscosity of the pentaerythritol mixed fatty acid ester at 40 ℃ is less than 28.6mm 2/s, and the ignition point is more than or equal to 310 ℃. The invention provides application of the pentaerythritol mixed fatty acid ester as base oil of synthetic ester insulating oil. The invention provides a preparation method of pentaerythritol mixed fatty acid ester, which comprises the steps of mixing pentaerythritol, fatty acid, a catalyst and a water-carrying agent, carrying out esterification reaction to obtain esterification reaction liquid, purifying the esterification reaction liquid to obtain the pentaerythritol mixed fatty acid ester,