MOLECULAR-ORBITAL STUDIES IN THE MGCL2-ETHYL BENZOATE-TICL4 SYSTEM

A modified extended Huckel method (ICONC) which includes core-core rep ulsion to energy terms was used to characterize the MgCl2/ethyl benzoa te (EB)/TiCl4 system by modelling the EB and TiCl4 adsorption on the ( 100-101) and (110) planes of MgCl2. The results show how the ester mod ifies the chemical and electronic states of adsorbed TiCl4. The appear ance of complexes at the surface, previously stated by FTIR experiment s, is supported by our theoretical calculation. The geometrical and st ructural factors governing the formation of precursors of active sites for propylene polymerization are also modelled.