Effects Of Cocatalyst And Halide In Homogeneous PNP/Cr(Ⅲ) Catalytic Systems For Ethylene Tetramerization

1-Octene is impotant chemical product and intermediate . It is widely used as a co-monomer for polyethylene, intermediats for plasticizer, fatty acid, detergent alcohols and oil dope. The ethylene copolymer with 1-octene as a co-monomer has better mechanical properties, optical properties, tear and impact resistance than those with 1-butene or 1-hexene as a co-monomer.According to the mechanisms of ethylene tetramerization, we have studied nine cocatalysts and seven donors in PNP/Cr(â…¢)/cocatalyst and/or donor catalytic systems. The studies focus on the 1-octene selectivity and catalyst activity. Some valuable results and conclusions are getted.The 1-octene formation selectivity and catalyst activity of the five alkylaluminiums are poor. So we should develop and study alkylaluminium cocatalyst systems. When MMAO is used as cocatalyst, we can get the best results. The precedence ordering about 1-octene formation selectivity and catalyst activity of the four alkylaluminoxanes is MMAO > MAO > EAO > i-BAO. We divide the seven donors to three kinds. The 1-octene formation selectivity and catalyst activity of dichloromethane are priory to trichloromethane and tetrachloromethane. The catalyst activity of 1,1,2-trichloroethane is better than 1,1,1-trichloroethane, and the 1-octene formation selectivity is also better. The 1-octene formation selectivity and catalyst activity of 1-chlorobutane are better than 1-bromobutane.