S-Trifluoromethyl Trifluoromonothioperoxyacetate

Ten mmoles of trifluoromethanesulfenyl chloride, CF3SC1, is allowed to react with excess silver trifluoroacetate at 25°C. for 

10 minutes in a 1-1. Pyrex vessel to produce S-trifluoromethyl trifluoromonothioperoxyacetate, CF3SOCOCF3. The reaction is quantitative. The CF3SOCOCF3 may be freed from trace amounts of trifluoromethanesulfenyl chloride, CF3SC1, by passage through a —78°C. Dry Ice-acetone bath, which retains the pure CF3-SOCOCF3. 

Ten mmoles of S-trifluoromethyl trifluoromonothioperoxyacetate are photolyzed for hour through Pyrex glass with a Hanovia Utility ultraviolet quartz lamp (140 watts), which produces bis(trifluoromethyl) sulfide and carbon dioxide quantitatively. Pure bis(trifluoromethyl) sulfide is retained in a —120°C. slush bath (diethyl ether) while carbon dioxide slowly sublimes into a —183°C. bath during trap-to-trap distillation. 

Bis(trifluoromethyl) sulfide exists as a colorless gas at room temperature and condenses to a colorless liquid. The vapor 

---