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US 7,829,749 B2Granted
Tetramerization
AssigneeNOVA Chemicals (International) S.A.
InventorsXiaoliang Gao, Charles Ashton Garret Carter, Lee Douglas Henderson
Life of this patent
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Abstract
A new P-N-P ligand is useful in ethylene oligomerizations. In combination with i) a source of chromium and ii) an activator such as methylalumoxane; the ligand of this invention may be used to prepare an oligomer product that contains a mixture of hexenes and octenes. The hexenes and octenes produced with this ligand contain very low levels of internal olefins when produced under preferred reaction conditions.
Claims6
A process for the oligomerization of ethylene comprising contacting ethylene under oligomerization conditions with a catalyst system comprising:
- a) A transition metal selected from the group consisting of Cr, V, Ti, Ni, and W;
- b) A ligand defined by the formula:
- wherein each of Ph1, Ph2, Ph3 and Ph4 is a phenyl group bonded to a phosphorus atom, with the provisos that
- i) at least one of Ph1, Ph2, Ph3 and Ph4 is ortho substituted with a halogen selected from the group consisting of fluorine, bromine and chlorine;
- ii) at least one of Ph1, Ph2, Ph3 and Ph4 does not have any substituents in ortho positions;
- and
- iii) R2 is selected from the group consisting of hydrogen, C1-20 hydrocarbyl and silyl;
- and
- c) an activator.
6 more elements
Dependencies are inferred from the claim text.