Patent ID: 7323524

Claim:
A process for polymerising olefins to branched polyolefins comprising contacting at least one olefin with a combination of catalysts comprising (a) a polymerisation catalyst; and (b) at least one co-catalyst in the form of an ethylene tetramerisation catalyst to produce 1-octene from ethylene which co-catalyst includes the combination of a transition metal compound; and a heteroatomic ligand described by the general formula (R) n A-B-C(R) m wherein A and C are independently an atom selected from the group consisting of phosphorus, arsenic, antimony, oxygen, bismuth, sulphur, selenium and nitrogen or said atom oxidized by S, Se, N or O where the valence of A and/or C allows for such oxidation; B is a linking group between A and C; the R groups are the same or different, and each R is independently selected from any homo or hetero hydrocarbyl group; and n and m for each R is independently determined by the respective valence and oxidation state of A and C; and provided that when the heteroatomic ligand is described by the following general formula (R 1 )(R 2 )A-B-C(R 3 )(R 4 ) wherein A and C are independently selected from the group consisting of phosphorus, arsenic, antimony, bismuth and nitrogen; B is a linking group between A and C; and R 1 , R 2 , R 3 and R 4 are independently selected from the group consisting of a hydrocarbyl group, a heterohydrocarbyl group, a substituted hydrocarbyl group and a substituted heterohydrocarbyl group; then R 1 , R 2 , R 3 and R 4 are defined by either: (i) no one or more of R 1 , R 2 , R 3 and R 4 have a substituent that is polar; and where R 1 , R 2 , R 3 and R 4 are independently aromatic, including heteroaromatic groups, not all the groups R 1 , R 2 , R 3 and R 4 have a substituent on the atom adjacent to the atom bound to A or C; or (ii) at least one of R 1 , R 2 , R 3 and R 4 has a polar substituent on a second or further atom from the atom bound to A or C and provided that none of R 1 , R 2 , R 3 and R 4 has any polar substituent on the atom adjacent to the atom bound to A or C.