Vanadiumpentafluoride reacts with polyfluorinated and polychlorinated olefins, alkadienes, cycloalkenes and cyclodienes in CFCl3 or without a solvent at −25° to 100°C, forming products of addition of two fluorine atoms across the CC bond.
Fluorination of polyfluoro-derivatives of benzene and diphenyl with vanadiumpentafluoride at −25 to −10 °C afforded fluorinated cyclohexadienes and cyclohexenes. Octafluoro- naphthalene was converted under these conditions to perfluoro- 1,4-dihydronaphthalene, perfluorotetralin, perfluoro-l,4,5,8- tetrahydronaphthalene and perfluoro-l,2,3,4,5,8-hexahydro- naphthalene.