Patent ID: 8076523

Claim:
An oligomerisation process comprising contacting at least one olefinic compound in the form of an olefin or a compound including an olefinic moiety with at least two different catalysts, including a tetramerisation catalyst and a further oligomerisation catalyst to produce an oligomeric product, which includes a mixture of at least one tetramer olefin and at least one other oligomer, wherein the tetramerisation catalyst comprises a combination of i) a source of a transition metal which transition metal is Cr; and ii) a ligating compound of the formula (R 1 ) m X 1 (Y)X 2 (R 2 ) n wherein: X 1 and X 2 are independently selected from the group consisting of N, P, As, Sb, Bi, O, S and Se; Y is a linking group between X 1 and X 2 ; provided Y excludes (CH 2 ) x Z(CH 2 ) y , where Z is —P(R 8 )—, —N(R 8 )—, —As(R 8 )—, —Sb(R 8 )— or —S—, and x and y are individually 1-15, and wherein R 8 is hydrogen or a halogen or a nitro group or a hydrocarbyl or a substituted hydrocarbyl group; m and n are independently 0, 1 or a larger integer; and R 1 and R 2 are independently hydrogen, a hydrocarbyl group, or a heterohydrocarbyl group, and R 1 is the same or different when m>1, and R 2 is the same or different when n>1, provided that: (a) if two or more of R 1 and R 2 are aromatic with a ring atom of the aromatic ring structure bound to either X 1 of X 2 , not more than two of said aromatic R 1 and R 2 have a substituent as a non-ring atom bound to a ring atom of the aromatic ring structure adjacent to the ring atom bound to X 1 or X 2 ; and (b) none of R 1 and R 2 are aromatic with a ring atom of the aromatic ring structure bound to either X 1 and X 2 and with a polar substituent as a non-ring atom bound to a ring atom of the aromatic ring structure adjacent to the ring atom bound to X 1 or X 2 ; and wherein the further oligomerisation catalyst is a catalyst comprising the combination of iii) a source of transition metal; and iv) a ligating compound of the formula (R 1 ) n′ A-B—C(R″) m′ wherein: A and C are independently selected from the group consisting of N, P, As, Sb, Bi, O, S and Se; B is a linking group between A and C; m′ and n′ are independently 0, 1 or larger integer; R′ and R″ are independently hydrogen, a hydrocarbyl group or a heterohydrocarbyl group; and R′ is the same or different when n′>1, and R″ is the same or different when m′>1and wherein the oligomeric product of the process contains from 9.5 wt % to 52.8 wt % of the tetramer olefin.