Patent ID: 7525009

Claim:
A process for the trimerisation of olefins comprising contacting an olefinic feedstream with a catalyst system at a pressure above 100 kPa (1 barg), which catalyst system includes the combination of a chromium compound; and a heteroatomic ligand of the following general formula (R 1 )(R 2 )A-B-C(R 3 )(R 4 ) where A and C are phosphorus; B is a linking group between A and C and; R 1 , R 2 , R 3 and R 4 are independently a hydrocarbyl group, a substituted hydrocarbyl group, a heterohydrocarbyl group or a substituted heterohydrocarbyl group and two or more of R 1 , R 2 , R 3 and R 4 are aromatic or hetero-aromatic groups containing at least one non-polar substituent on the atom adjacent to the atom bound to A or C.