FLUOROCYCLOHEXANES. PART XVI. THE SIX H-TRIFLUOROMETHYLDECAFLUORO- AND TWO OF THE 2H,4H-TRIFLUOROMETHYLNONAFLUORO-CYCLOHEXANES

Article abstract of DOI:10.1016/S0022-1139(00)81515-8

Fluorination of benzotrifluoride by cobaltic fluoride at 260-280 deg gave, besides the fluorocarbon, the six possible tridecafluoromethylcyclohexane isomers, and two 2H,4H-dodecafluorides.Of the C7HF13 compounds, only the cis-2H-, and the cis- and trans-4H-isomers could be isolated pure.The two 3H-isomers were made by pyrolysis of perfluoro(1-methyl-3-isopropylcyclohexane) in the presence of toluene.The trans-2H-isomer was made by further fluorination of one of the 2H,4H-dodecafluorides.Aqueous potash and the cis-2H-tridecafluoride gave 1-trifluoromethylnonafluorocyclohex-1-ene, which with stronger alkali hydrolysed to 1-carboxynonafluorocyclohex-1-ene.The cis- and trans- 2H and 4H-tridecafluorides were dehydrofluorinated by sodium fluoride at 320-380 deg (the cis-isomer of each pair reacted faster than the trans-: axial versus equatorial hydrogen) to give, respectively, the 1-trifluoromethylnonafluoro-ene and the 4-trifluoromethyl-isomer.The latter was isomerised to the former by sodium fluoride at 500-600 deg.The 1-CF3-ene gave hexafluoroglutaric acid on oxidation with alkaline potassium permanganate.