Tetramerization ligands
AssigneeNOVA Chemicals (International) S.A.
InventorsCharles Ashton Garret Carter, Xiaoliang Gao
Life of this patent
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Abstract
An ethylene oligomerization catalyst which contains a bridged diphosphine ligand having the formula (R1)m(X1)nP1-bridge-P2(R2)X2 wherein R1 and R2 are independently selected from the group consisting of hydrocarbyl and heterohydrocarbyl; X1 is selected from the group consisting of halogen, hydrocarbyl and heterohydrocarbyl; m is 1 or 2; n is 0 or 1; m+n=2; bridge is a divalent bridging group bonded to P1 and P2; and X2 is halogen. The present ligands differ from prior diphosphine ligands used in olefin oligomerization processes in that at least one halide substituent is directly bonded to at least one P atom of the ligand.
Claims10
A process for the oligomerization of ethylene wherein ethylene is contacted under oligomerization process conditions with an oligomerization catalyst system comprising:
- a) a source of chromium;
- b) a ligand of the formula (R1)m(X1-bridge-P2(R2)X2 wherein
- R1 and R2 are independently selected from the group consisting of unsubstituted phenyl and o-fluorophenyl;
- X1 is selected from the group consisting of halogen, unsubstituted phenyl and o-fluorophenyl;
- m is 1 or 2;
- n is 0 or 1;
- m +n =2;
- bridge is a divalent bridging group bonded to P1 and P2;
- and
- X2 is halogen;
- and
- c) an activator.
Dependencies are inferred from the claim text.