Study On Novel PNP Ligand Synthesis And Property In Ethylene Oligomerization

α-olefins are important organic materials and chemical products. They are extensively used as co-monomers for linear lowdensity polyethylene, intermediats for base lubricating oil,α-olefin sulfonate, plasticizer alcohol, fatty acid, and so on. The ethylene copolymer with 1-octene as a co-monomer has good mechanical properties, optical properties,anti-tear and impact intensity.The Cr-catalyzed system is highly active for ethylene tetramerization among ethylene oligomerization catalysis. And it has led to considerable interest in research domain. The typical combination is C(rⅢ)/PNP ligand /MAO system, with MAO as cocatalyst. The research is focused on two sides: on the one hand, varying the eletronic and steric features of various PNP ligands to improve the coordination environment of Cr; on the other hand, exploring the effect of more well-defined counterions of MAO to reduce the production costs.In this study, three novel bis-(phenylphosphino)amine ligands were synthesized based on the mechanism of ethylene tetramerization. One is bis-(dipenylphosphino)amine ligand, the other two is bis-(dipyrrolphosphino)amine ligands. The catalytic activity and product selectivity of corresponding catalytic system were investigated. The ethylene tetramerization products were analysised qualitatively and quantitatively by gas chromatography / mass spectrometry. A series of valuble results and conclusions are obtained.Four alkylaluminium cocatalysts (riethylaluminium, tri-n-hexylaluminum, triisobutylalumniu and diethylaluminum chloride) and three alkylaluminoxane cocatalysts (methylaluminoxane, ethylaluminoxane, and isobutylaluminoxane) were examined in this study. The results showed that the two novel bis-(phosphino)amine ligands are effective oligomerization ligands, all of the cocatalysts were effective for ethylene oligomerization catalysts. The corresponding catalyst system of ligand 3 is highly effective ethylene trimerization catalysis, achieving selectivity as high as 93.2% for 1-hexene. The activity of catalyst system with ligand 2 is higher, and the selectivity for 1-octene is 80.88%.