US Patent 7696397 Catalytic composition and its application to olefin oligomerization

An improved catalytic composition for oligomerization, in particular dimerization, of monoolefins comprises the product resulting from bringing the following three constituents into contact in any order:a) at least one divalent nickel compound;b) at least one hydrocarbylaluminium dihalide, optionally enriched with an aluminum trihalide; andc) at least one organic Bronsted acid;