Chemical Remediation and Valorization of the Electrical Insulating Gas Sulfur Hexafluoride, the Most Potent Greenhouse Gas

Sulfur hexafluoride (SF6) is a gas used in electrical switchgear. SF6 is the most potent industrial greenhouse gas (GHG), with a global warming potential over 23500 times that of CO2. As our electrical grid becomes more distributed, numbers of switchgear increases (for example, each wind turbine may have switchgear containing SF6).

The electrical industry embraced SF6, because despite high global warming potential, it rapidly quenches electrical arcs, and is non-toxic, allowing safer and smaller switchgear. Despite SF6’s favourable properties, the electrical industry is actively seeking alternatives since surplus SF6 is extremely difficult to dispose of. SF6 is very unreactive chemically. When it leaks to the atmosphere, it is highly persistent, due to lack of chemical pathways that destroy it. As it is replaced, tools to dispose of surplus SF6 are needed. Currently, the main disposal of SF6 is through incineration in highly energy-intensive electrical arc plasma furnaces.

Recently, certain chemicals have been found to react with SF6, and less energy-intensive chemical reactions are attractive ways to dispose of unwanted SF6. Unfortunately, these chemicals are expensive, so are not competitive with the electric furnaces. We have recently found that electron-rich phosphorus compounds can react with sulfur hexafluoride catalytically at room temperature, with no added energy.

In this project,

• we propose to further explore compounds reactive with sulfur hexafluoride to make a mild, cheap, and simple method to dispose of this potent GHG, which would be the first primary outcome.
• The second primary outcome would be to use catalysis to only partially react SF6, accessing pentafluorosulfanyl (SF5) compounds.

These are highly sought-after entities for medicinal chemistry, that are currently difficult to access. Combining preparation of SF5 compounds with SF6 disposal would add further value to this chemistry and establish Nova Scotia as a world-leading centre of SF6 chemistry research and SF5 functionalization.