Patent ID: 7273959

Claim:
A catalyst composition suitable for the trimerization of olefinic monomers, wherein the catalyst composition comprises: a) a source of chromium, molybdenum or tungsten; b) a ligand of general formula (I); (R 1 )(R 2 )P—X—P(R 3 )(R 4 ) (I) wherein: X is an ethylene bridging group which contains from 2 to 6 carbon atoms; R 1 and R 3 are independently selected from the group consisting of optionally substituted phenyl groups which do not contain a polar substituent at any of the ortho-positions; R 2 and R 4 are independently selected from aromatic groups, each R 2 and R 4 bearing a polar substituent on at least one of the ortho-positions; and c) a cocatalyst.