Theoretical Analysis of the Decomposition Pathways and Species of Environmentally Friendly Insulation Gas C 6 F 12 O Based on the DFT and TST

C 6 F 12 O (1,1,1,2,2,4,5,5,5-nonafluoro-4-(trifluoromethyl)pentan-3-one) is one of the most potential alternative insulation medium to SF 6 due to its excellent electrical strength and environmental effect. Although several works on the insulation and decomposition properties of C 6 F 12 O have been carried out in recent years, the detailed decomposition pathways and mechanism of C 6 F 12 O haven’t been revealed up to now. A comprehensive analysis of the decomposition mechanism of C 6 F 12 O is performed through high-level quantum chemistry calculations with DFT and TST in this paper. The results show that more than ten decomposition products are formed. C 4 F 10(a) , C 5 F 12(b) , and CO can be used for evaluating slight failures. C 3 F 8 , C 2 F 6 , C 2 F 4 , C 3 F 6 , C 4 F 10(b) , C 5 F 12(a) , C 6 F 14(a) and C 6 F 14(b) etc. can be taken as typical products when a general failure is caused in the equipment. CF 4 can be used as a basis for determining whether a serious failure has occurred in the gas-insulated electrical equipment. According to the analysis, primary decomposition products such as C 4 F 10(a) and C 5 F 12(b) have relatively high dielectric strength. Besides, the concentration of decomposition products of C 6 F 12 O is low to have a major impact on the overall electrical performance at normal conditions. However, the insulation properties of C 6 F 12 O gas mixtures after the prolonged operation or multiple arc extinctions deserve further investigation. In the view of human safety and environmental effect, several toxic products such as C 2 F 4 , CO, and C 3 F 6 should be effectively managed and handled with care. This paper could provide a theoretical basis for related engineering applications.