Abstract: An improved catalyst composition for the metathesis of olefins comprises at least one porous mineral carrier based on alumina, at least one compound of rhenium, molybdenum, or tungsten, and further includes silicon in an oxide form.

Abstract: An improved catalyst composition for the metathesis of olefins comprises at least one porous mineral carrier based on alumina, at least one compound of rhenium, molybdenum, or tungsten, and further includes silicon in an oxide form.

Abstract: Nickel, aluminum and chlorine derivatives which remain dissolved in olefin oligomers, after oligomerization in the presence of a nickel, aluminum, and chlorine-containing catalysts, are removed by successive treatments with:(a) anhydrous ammonia,(b) an aqueous solution of alkali metal hydroxide, a treatment with an aqueous solution containing at least one hydroxy-acid or at least one alkali metal salt of said hydroxyacid being performed after treatment (a) and before or after or simultaneously with treatment (b), and preferably a treatment with oxygen or with an oxygen-containing gas being performed before or after treatments (a) and (b) or simultaneously with these treatments. Preferably, tartaric acid or an alkali metal tartrate is used.

Abstract: For polymerizing unsaturated hydrocarbons into oligomers with acid catalysts, there are employed liquid catalyst compositions containing a Bronsted acid and a sulfone of formula R--SO.sub.2 --R', wherein R and R' are each separately a monovalent radical containing from 1 to 8 carbon atoms or form together a divalent radical having from 3 to 12 carbon atoms, the acid concentration being at least 10.sup.-.sup.5 moles per liter of sulfone and at most the saturation concentration without exceeding 5 moles per liter of sulfone. The catalysts may be dispersed in an inert hydrocarbon solvent and Lewis acids may also be added.