Patent ID: 7511183

Claim:
A process for tetramerisation of olefins comprising contacting an olefinic feedstream with a catalyst system which includes the combination of a transition metal compound; a heteroatomic ligand described by the following 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 0, where the valance 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 the group consisting of a hydrocarbyl group, a hetero hydrocarbyl group, a substituted hydrocarbyl group, and a substituted hetero hydrocarbyl group; 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 each of R 1 , R 2 , R 3 and R 4 is independently selected from the group consisting of a hydrocarbyl group, a hetero hydrocarbyl group, a substituted hydrocarbyl group, and a substituted hetero hydrocarbyl group, any substituents that may be part of one or more of R 1 , R 2 , R 3 and R 4 are non electron donating and where R 1 , R 2 , R 3 and R 4 are independently aromatic, including hetero aromatic 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; and an activator selected from the group consisting of organoaluminium compounds, organoboron compounds, organic salts, inorganic acids and salts, wherein the organoaluminium compounds are selected from the group of compounds of the formula AIR 3 , where each R is independently a C 1 -C 12 alkyl or a halide, aluminoxanes and modified aluminoxanes.