Patent ID: 8329608

Claim:
A method of oligomerizing olefins, comprising: (A) preparing an oligomerization catalyst, wherein: (i) the catalyst comprises a chromium-containing compound, a pyrrole-containing compound, a non-halide metal alkyl, a metal halide-containing compound, and optionally a solvent, and (ii) the catalyst is prepared by: (a) contacting a composition comprising the chromium-containing compound with a portion of the non-halide metal alkyl such that the molar ratio of non-halide metal alkyl to chromium-containing compound is less than about 1.5:1, and (b) subsequently contacting the components from (a) with a composition comprising the metal halide-containing compound and the remaining components of the catalyst compound including an additional amount of the non-halide metal alkyl; and (B) oligomerizing olefins by contact with the catalyst in a reaction zone.