Patent ID: 7410927

Claim:
A catalyst composition comprising: a) a transition metal compound with the following formula: wherein: M is chromium or vanadium; R, R 1 , R 2 , R 3 , and R 4 are independently an alkyl, aryl, alkaryl or arylaryl group, anyone of which has 1-20 carbon atoms; a is 1, 2 or 3; Z is a monovalent anionic group; Z′ is a monovalent anionic group; b is 0, 1 or 2, and c is 0, 1 or 2; L is a neutral donor ligand; d is 0, 1 or 2; and b) a chemically-treated solid oxide comprising a solid oxide treated with an electron withdrawing anion; wherein: the solid oxide comprises silica, alumina, silica-alumina, or mixtures thereof; and the electron withdrawing anion comprises fluoride, chloride, bromide, sulfate, or any combination thereof.