Lithium tetrafluorocobaltate

The tetrafluorocobaltates of the alkali metals show12 considerable differences in their reactions with benzene. Lithium tetrafluorocobaltate(III) at 100-130 C gives 3,3,6,6-tetra-fluorocyclohexa-1,4-diene (13) of over 90% purity. This compound has long been postulated1,549 as a major intermediate in the fluorination with cobalt(III) fluoride. The sodium, potassium, and rubidium salts give similar product mixtures (ca. 8 compounds), most being polyfluoroenes (e.g. 14, 8% 15, 12% 16, 35%). 

Preparation.— The fluorination, with transition-metal fluorides, of aromatic and heterocyclic compounds, if carried out under mild enough conditions may produce olefinic compounds (Vol, 1, pp. 5,242, and 245). Thus fluorination of benzene with lithium tetrafluorocobaltate(m) at 100—130 °C yields >90% of 3,3,6,6-tetrafluorocyclohexa-l,4-diene at 250 °C a complex... 

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