Theoretical Consideration of the External Donor of Heterogeneous Ziegler–Natta Catalysts Using Molecular Mechanics,Molecular Dynamics,and QSAR Analysis

In the previous paper we calculated the most stable structure of the catalyst and cocatalyst of metallocene catalyst systems using molecular dynamics and molecular mechanics. In this paper we postulate the active site of the heterogeneous Ziegler–Natta catalyst, and analyze it by the same methods to clarify the main factors that control the activity and molecular weight distribution of the heterogeneous catalyst systems. The roles of the external donor were also considered, and we found that the interaction energy between an external donor and the active site of the catalyst, as well as the structural factors of the external donor itself, are strongly related to both activity and molecular weight distribution. These results reveal that molecular dynamics and molecular mechanics calculations are also effective methods to screen the heterogeneous catalyst systems.