Preparation of perfluoralkanes

Described is a process for the stabilization or purification of perfluoroalkanes, which, due to the preparation process, still contain polyfluoroalkanes. The stabilization or purification is effected by reacting the polyfluoroalkanes with fluorine under elevated pressure at elevated temperature. The process is particularly suitable for purifying perfluoroalkanes starting from mixtures containing perfluoroalkanes and polyfluoroalkanes. This gives perfluoroalkanes which are essentially free from polyfluoroalkanes. The advantage of the process is the fact that perfluorination is rapid and yet without an appreciable formation of by-products or degradation products.