Chen Min, Zhang Tao, Zhang Jinyuan, Liu Chunyi, Chen Dong, Zhang Jin
College of Electrical Engineering and New Energy, China Three Gorges University, Yichang 443002, China.
College of Physics and Electronic Information Engineering, Hubei Engineering University, Xiaogan 432000, China.
Molecules. 2025 Mar 24;30(7):1431. doi: 10.3390/molecules30071431.
The functional groups in the molecular structure of natural ester insulating oil have a significant impact on its physicochemical and electrical properties. This article takes the novel synthetic ester TME-C and traditional natural ester GT molecules as research objects, and based on density functional theory (DFT) calculations, systematically explores the micro-mechanism of the effects of C=C double bonds, ester groups (-COOC), and β-H groups on the performance of insulating oils. The results show that the chemical stability and anti-aging ability of the TME-C molecule are significantly improved by eliminating the C=C double bond and β-H group. The electronic behavior of the TME-C molecule is mainly controlled by the ester group (-COOC), while the GT molecule is significantly affected by the unsaturated C=C double bond, resulting in a significant difference in the mode of electronic transition between the two molecules: the TME-C molecule shows the n→σ∗ transition, while the GT molecule is the π→π∗ transition. In addition, the HOMO orbital energy level, electron transition energy, and ionization energy of the GT molecules are lower than those of the TME-C molecules. Under the action of an external electric field, the TME-C molecules exhibit excellent dielectric properties. In summary, the TME-C molecules not only overcome the aging defects of traditional natural ester insulating oils, but also possess excellent insulation properties, making it a new type of insulating oil material with broad application prospects.
天然酯绝缘油分子结构中的官能团对其物理化学和电气性能有显著影响。本文以新型合成酯TME-C和传统天然酯GT分子为研究对象，基于密度泛函理论（DFT）计算，系统地探究了C=C双键、酯基（-COOC）和β-H基团对绝缘油性能影响的微观机制。结果表明，通过消除C=C双键和β-H基团，TME-C分子的化学稳定性和抗老化能力得到显著提高。TME-C分子的电子行为主要受酯基（-COOC）控制，而GT分子则受不饱和C=C双键的显著影响，导致两种分子的电子跃迁方式存在显著差异：TME-C分子表现为n→σ∗跃迁，而GT分子为π→π∗跃迁。此外，GT分子的最高占据分子轨道（HOMO）能级、电子跃迁能量和电离能均低于TME-C分子。在外部电场作用下，TME-C分子表现出优异的介电性能。综上所述，TME-C分子不仅克服了传统天然酯绝缘油的老化缺陷，还具备优异的绝缘性能，使其成为一种具有广阔应用前景的新型绝缘油材料。
