The Synthesis Of New Titanium Family Of Olefin Polymerization Catalysts And Their Catalytic Performance

1. Metallocene catalysts, (C₃H₅C₅H₄)RCpZrCl₂ (R= allyl, 1; H, 2; ^tBu; 3; ^tBu₂, 4), containing an allyl group, have been synthesized and characterized. In the presence of excess methylaluminoxane (MAO), the allyl group of the metallocene catalysts can be co-polymerized in the polymer chain as co-monomer in the polymerization process and so they were also called as self-immobilized catalysts for ethylene polymerization. The molecular structures of catalyst 1 and 3 have been determined by single-crystal X-ray diffraction. The polymerized metallocene catalyst 5 is prepared by the copolymerization of allyl metallocene complex with styrene in the presence of radical initiator. The result of ethylene polymerization showed that the polymerized metallocene catalyst kept high activity of 2300kgPE/molM.h for ethylene polymerization and was a potential supported catalyst for olefin polymerization.2. This thesis discussed the synthesis and characterization of SBA-15 supported metallocene catalyst. The function of SBA-15 in controlling the morphology and improving the properties of polymers was studied through ethylene polymerization. The two-dimensional ordered channel structure of SBA-15 could control the relative position of polyethylene chains. As a result, the polyethylene fibers were obtained.3. The half-sandwich Zr complexes of CpZr(acac)₂Cl(7), Cp*Zr(acac)₂Cl(8), CpZr(acac)₃(9) and CpZr(tfac)₃(10) ( acac=acetylacetonato, tfac= trisfluoroacetylacetonato) have been synthesized and characterized. The molecular structures of 7, 9 and 10 have been determined by X-ray diffraction methods. The geometrys around Zr atom in the tis(β-diketonato) Zr complexes 9 and 10 is pentagonal bipyramid. When activated by excess MAO, these catalysts were well active for ethylene polymerization, offering polyethylenes with high molecular weights. Catalyst 9 showed very high activity for ethylene polymerization of up to 7100kgPE/molZr.h at 5 atm and the resulted polymer has a high molecular weight (M_v = 89×10⁴). Catalysts 7 and 8 were also active for ethylene/1-hexene copolymerization.4. The Ti and Zr half-sandwich catalysts 11-16 with [O(S),N,O] tridentate Schiff base ligand have been synthesized. The molecular structures of catalysts 11,12, 13 and 15 have been determined by X-ray diffraction methods. The nitrogen atoms in 11,12,13 and 15 are coordinated to the metal centers. In the presence of excess MAO, the Zr catalyst 13 exhibited more active than the Ti complex for ethylene polymerization with a activity of 1.53×10⁵gPE/molZr.h at 70℃, 1atm. [S,N,O] tridentate Schiff base Ti complex 15 is more active than its analogue 11. Catalyst 11 was also active for ethylene/1-hexene copolymerization.