Thermally and oxidatively stable perfluorinated tertiary amines of the formula: ##EQU1## ARE DISCLOSED, AS WELL AS THE PROCESS FOR MAKING THESE AND OTHER COMPOUNDS. The carbonyl group of imides or amides is reduced with SF.sub.4 using HF as the reaction solvent at a reaction temperature of 25.degree.-300.degree.C. Cyclic imides can be used as starting compounds, and tertiary amines containing unsaturated moieties can be produced. The perfluorinated tertiary amines have various uses in view of their high degree of thermal and oxidative stability, including uses as hydraulic fluids or transformer dielectric fluids.