Verfahren zur Herstellung von 4-Methylpenten-1

A hydrocarbon compound of an alkali metal other than lithium is obtained together with metallic lithium when an organo-lithium compound LiR in which R is aryl, cycloalkyl or C2-C18 alkyl is reacted with a dispersion of another alkali metal in an inert hydrocarbon. In an example, potassium dispersed in a diesel oil boiling in the range 180-220 DEG C. is reacted with butyl lithium and the butyl potassium separated by decantation from the resulting lighter lithium.ALSO:4-Methylpentene-1 is obtained by dimerization of propylene in an inert hydrocarbon in the presence of lithium obtained by reacting an organo-lithium compound LiR (in which R is aryl, cycloalkyl or C2-C18 alkyl) with another alkali metal. Dimerization is effected at 100-250 DEG C. preferably in a hydrocarbon which does not boil at the dimerization, e.g. a diesel oil boiling in the 180-220 DEG C. range. To form the catalyst potassium is melted in the hydrocarbon to form a dispersion which is cooled with stirring. Butyl lithium in the same hydrocarbon is added. The organo-potassium compound may be removed or the whole mixture used as catalyst.ALSO:Metallic lithium as a fine dispersion in a hydrocarbon is obtained by reacting another alkali metal, preferably potassium, in dispersion in an inert hydrocarbon with an organo-lithium compound LiR in which R is aryl, cycloalkyl or C2-C18 alkyl. The hydrocarbon may be a diesel oil boiling in the range 180-220 DEG C., and the lithium compound butyl lithium. The butyl potassium also formed is separated from the lighter lithium by decantation.ALSO:A mixture of lithium and an organo-derivative of another alkali metal, for use as catalyst in dimerising propylene, is obtained by reacting a dispersion of an alkali metal, preferably potassium, in an inert hydrocarbon with an organo-lithium compound LiR, in which R is aryl, cycloalkyl, or C2-C18 alkyl. The hydrocarbon may be a diesel oil boiling in the range 180-220 DEG C. p