A novel and efficient preparation route of insulating gas-heptafluoroisobutyronitrile was developed. The synthetic route involved halogen-exchange fluorination, decomposition of bis-(perfluoroisopropyl) ketone and dehydration reaction. Overall, the desired compound was produced without the use of extremely toxic and expensive substances. Structures of the as-obtained products were determined by 19F NMR, 13C NMR, IR and GC-MS. The effects of several variables on reaction yield including nature of potassium fluoride, the catalyst dosage, temperature, solvent and molar ratio of raw materials were all investigated. The results indicated that the total yield of heptafluoroisobutyronitrile could reach 42% from original materials under optimal conditions and the mechanism of the reaction was proposed.
Keywords: bis-(perfluoroisopropyl) ketone; heptafluoroisobutyramide; heptafluoroisobutyronitrile; insulating gas; synthesis.