DE2208115

The method and installation are for the enrichment of one of the constituents of an initial mixture containing at least two hydrocarbons, especially with neighboring boiling points, and of which one at least possesses mobile hydrogens. Fractional distillation of this mixture is effected in contact with a phase containing an organo-metallic compound derived from a compound having itself mobile hydrogens and in which the metallic atoms are substituted in reversible manner for these mobile hydrogens. The vapor phase enriched in the hydrocarbon of the initial mixture which has the least affinity for metallic atoms is collected and an unvaporised phase enriched in the hydrocarbon of the initial mixture which has the most affinity for metallic atoms in partially metalled form is also produced. The affinity of the hydrocarbons concerned for the metallic atoms varies sometimes considerably from one hydrocarbon to the other and from one isomer to the other. By conducting operations continuously and in countercurrent in a distillation column relatively few stages suffice to obtain efficient separation of the hydrocarbons. The transmetallation reactions are facilitated by basic catalysts such as tertiary amines and chelating polyamines.