One potential source of the potent greenhouse gas SF5CF3: the reaction of SF6 with fluorocarbon under discharge

In this paper, we verified Sturge's speculation (Science, 2000) that SF5CF3 might originate as a breakdown product of SF6 in high-voltage equipment via the spark discharge reactions of SF6 with a few fluorocarbons, such as CHF3 and CH2F2. However, SF5CF3 was unlikely to be formed from CF3 group attacking SF5 radical based on the results that no SF5CF3 was detected in the reactions of SF6 with CF4 or CF3Br. The reactions of SF6 with CHF3 and CH2F2 under spark discharge produced SF5CF3 and the yields of SF5CF3 were determined as a function of the initial fluorocarbon to SF6 ratio, total gas pressure and discharge time. The reaction processes of SF6 with CHF3 and CH2F2 were discussed briefly.