Disulfides sulfur trifluorides

The electrolysis of hydrogen fluoride containing carbon disulfide and a little sodium fluoride gives a gaseous product containing CF3SF6, CF2(SF6)2, and CF2(SF3)2, difluoromethylenebis(sulfur trifluoride (51). 

Sulfur trifluorides from disulfides RSSR 2 RSF3... 

Carbon disulfide gives an essentially quantitative yield of carbon tetralluoride and sulfur on reaction with sulfur tetrafluoride at 450 C in the presence of arsenic trifluoride as a catalyst. At lower temperature, bis(fnfiuoromethyl) polysulfides are formed [//] (equation 15). 

When treated with chlorine trifluoridc in CFC-12 at — 78 C, trifluoromethanesulfenyl chloride and bis(lrifluoromethyl) disulfide are transformed into trifluoromethylsulfur trifluoride (95%) and bis(trifluoromethyl)sulfur difluoride (90%). respectively.121... 

Sulfur tetrafluoride undergoes addition to perfluoroalkenes, e.g. 1 and 4, in the presence of cesium fluoride to give bis(perfluoroalkyl)sulfur difluorides and perfluoroalkylsulfur trifluorides.188,198 The ratio of the products is controlled by the reactant ratios. The role of cesium fluoride is ascribed to the formation of perfluorocarbanions which then subsequently attack sulfur tetrafluoride.188 Perfluoroalkyl disulfides, which are formed as side products, arise from the pyrolysis and disproportionation of bis(perfluoroalkyl)sulfur difluoridcs.189... 

Substitution of sulfur with sulfur tetrafluoride takes place in the presence of a catalyst. So carbon disulfide and sulfur tetrafluoride yield quantitatively carbon tetrafluoride with arse-nic(III) trifluoride, whereas, at lower temperatures, bis(trifluoromethyl) polysulfides are formed in the presence of boron trifluoride.21... 

Organic sulfur trihalides (RSX3, X = Cl, F) are known. The arylsulfur trifluorides can be obtained by oxidation of the disulfide with silver difluoride but this reaction fails for alkyl compounds. Fluoroalkenes provide a valuable source of compounds according to equation (52), which is catalyzed by cesium fluoride. 

The polymerization of cydic disulfides to polydisulfides has been reported in the 1940s and 1950s. In some cases the polymerizations occur spontaneously. Tobolsky et reported that l-oxa-4,5-dithiacycloheptane and l,3-dioxa-6,7-dithiacyclononane are polymerized by cationic initiators such as sulfuric acid or boron trifluoride. Davis and Fettes repotted the anionic polymerization of various cyclic disulfides. In the same period it was also described that cyclic disulfides can copolymetize with vinyl monomers such as styrene and butyl acrylate with AIBN as initiator. That the incorporation of the disulfide was due to copolymerization and not by chain transfer was established by comparing the thermal polymerization of styrene in the presence of dibutyl disulfide and in the presence of l-oxa-4,5-dithiacycloheptane. In the first case, the polymer contained 2 sulfur atoms per macromolecule as a result of transfer reactions and in the second case 4-20 sulfur atoms depending on the ratio of monomers. 

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