The structure and energy characteristics of the adducts formed in the Cp2TiMeCl/(AlMeCl2 + H2O) catalytic system

The mechanism of activation of the Cp 2 TiMeCl/AlMeCl 2 catalytic system for polymerizing ethylene in the presence of H 2 O was studied using the density functional theory. The geometries of the titanocene-aluminum chlorideadducts formed in this system were optimized and their energies calculated. The adducts can play the role of catalytic centers of polymerization. The energies of adduct heterolysis (with the formation of Cp 2 TiMe + ) and the energies of formation from neutral precursors were used as criteria of the ability of such adducts to act as catalytic particles. Of all compounds under consideration, the most promising one is the adduct of the composition Cp 2 Ti(Me)...Cl...AlCl 2 -O-Al 2 Cl 5 . The catalytic system activity should therefore become higher as the content of this compound increases. The calculation results are compared with experimental data on the kinetics of ethylene polymerization.